Fwd: Human Spaceflight (and Voyager) News - September 13, 2013

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From: "Moon, Larry J. (JSC-EA411)" <larry.j.moon@nasa.gov>
Date: September 13, 2013 6:43:21 AM GMT-06:00
To: "Moon, Larry J. (JSC-EA411)" <larry.j.moon@nasa.gov>
Subject: FW: Human Spaceflight (and Voyager) News - September 13, 2013

Happy Flex Friday everyone!  Have a great and safe weekend.

 

 

NASA TV:

• 8 am Central (9 EDT) – REPLAY of Voyager News Conference
• 9 am Central (10 EDT) – File of Exp 37/38 crew departure from Star City for Baikonur

 

IN CASE YOU MISSED IT...

 

Arsenio Hall Talks to the International Space Station

 

Hall talked with ISS Expedition 37 Flight Engineer Karen Nyberg the other day. Here's how it was presented on his show last night:

 

http://www.arseniohall.com/video/interviews/1601_Arsenio_Talks_to_the_International_Space_Station/index.html

 

Human Spaceflight News

Friday – September 13, 2013

 

The 1,588 pound Voyager 1 launched from KSC atop a Titan IIIE-Centaur rocket on Sept. 5, 1977

 

HEADLINES AND LEADS

 

Spacemen 'flew blind' from space station as sensors failed

 

Agence France Presse

 

The three crew of the International Space Station (ISS) who returned to Earth this week endured a hair-raising descent after their height sensors failed, a Russian cosmonaut revealed on Friday. Pavel Vinogradov said that he and the two other crew of the Soyuz capsule which touched down in Kazakhstan Wednesday had groped their way through the landing after they lost all data about their height from the ground. "There were problems. For some reason after the undocking all our parameters disappeared. Essentially, after the undocking, we flew blind," he said at the Star City cosmonaut training centre outside Moscow, quoted by Russian news agencies.

 

NASA officials talk challenges, and thrills, of capturing an asteroid

 

Deborah Netburn - Los Angeles Times

 

Having trouble getting excited about NASA's planned mission to redirect an asteroid? Maybe William Gerstenmaier can help. "Turn off your logical side and turn on your touchy-feely side, the one you almost never use," Gerstenmaier, associate administrator for NASA's Human Exploration and Operations Directorate, told attendees of an aeronautics and astronautics conference Wednesday in San Diego. "Then jump up and down and do some break-dancing. We're going to grab a space rock and we're going to move it!" Gerstenmaier's comments came at the end of an hour-long panel discussion that included five NASA officials charged with coordinating the agency's plan to capture an asteroid, drag it into lunar orbit and then send a pair of astronauts to meet up with it and collect a sample.

 

6 Creative Proposals For Deflecting Earth-Threatening Asteroids

 

Elise Ackerman - Forbes

 

During a Congressional hearing last March, Rep. Bill Posey asked NASA Administrator Charles Bolden what the space agency would do if it learned that a large asteroid was three weeks away from striking Earth. "The answer to you is if it's coming in three weeks, pray," Bolden responded. "The reason I can't do anything in the next three weeks is because for decades we have put it off." It wasn't the answer lawmakers wanted to hear. Just one month earlier, an asteroid the size of a large school bus had exploded outside the Russian city of Chelyabinsk, injuring around 1,500 people. The same day another asteroid, this one more than twice as big, buzzed the planet from a height of 17,200 miles, coming closer than communications satellites in geostationary orbits. Within weeks, the White House released a proposed budget for NASA that included $78 million for a manned mission in which astronauts would lasso a small asteroid and tow it into stable orbit around the moon.

 

NASA has plan to harvest lettuce in space

 

Robert Stanton - Houston Chronicle

 

Dining aboard the International Space Station can be a bit boring, considering that most of the food is prepared by adding water to the package. But change is on the horizon. This year, NASA plans to harvest a plot of romaine lettuce in zero-gravity under pink LED lights. While the produce should be dining-ready in 28 days, it'll be awhile before the astronauts will be able to eat it. The Vegetable Production System (VEGGIE) Program is NASA's first attempt to grow produce in space that could sustain astronauts.

 

Astronaut gave 'Gravity' advice to Sandra Bullock from space

 

Robert Pearlman - collectSPACE.com

 

Cady Coleman had just finished watching Sandra Bullock in the "The Blind Side" when the actress reached out to her for advice. Coleman, a self-described fan, had never met or spoken to Bullock before and so the contact in the spring of 2011 came out of the blue, or more appropriately, the blackness of outer space. A veteran NASA astronaut, Coleman was about two-thirds of her way through a 5-month stay aboard the International Space Station at the time. Bullock, meanwhile, was set to portray an astronaut in director Alfonso Cuarón's movie, "Gravity" (opening in theaters on Oct. 4).

 

Astronaut Does A 'Moon' Walk In The Sea

Better Yet, It's Just One Of Many Recent Underwater Missions

 

Elizabeth Howell - Universe Today

 

The black-and-white tones of this photo evoke a famous Moon walk of 1969, but in reality it was taken in Mediterranean waters just a few days ago. For the "Apollo 11 Under The Sea" project, European Space Agency astronaut Jean-François Clervoy and ESA astronaut instructor Hervé Stevenin took on the roles of Neil Armstrong and Buzz Aldrin, the first two men to walk on the moon during Apollo 11. A major goal was to test the Comex-designed Gandolfi spacewalk training suit (based on the Russian Orlan spacesuits) during the sojourn. The mission was considered the first step (literally and figuratively) to figuring out how Europeans can train their astronauts for possible Moon, asteroid and Mars missions in the decades to come.

 

HEADING OFF INTO INTERSTELLAR SPACE

 

Voyager 1 finally crosses into interstellar space

 

William Harwood - CBS News

 

Covering nearly a million miles a day, NASA's nuclear-powered Voyager 1 spacecraft, 36 years and 12 billion miles from Earth, has crossed the boundary between the sun's influence and interstellar space, sailing into the vast gulf between the stars to become humanity's first true starship, scientists announced Thursday. "In leaving the (solar system) and setting sail on the cosmic seas between the stars, Voyager has joined the other historic journeys of exploration such as the first circumnavigation of the Earth and the first footprint on the moon," said Voyager project scientist Ed Stone. "This historic step is even more exciting because it marks the beginning of a new era of exploration for Voyager, the exploration of the space between the stars."

 

NASA: Voyager 1 Probe Has Left the Solar System

 

Alicia Chang - Associated Press

 

NASA's Voyager 1 probe has left the solar system, boldly going where no machine has gone before. Thirty-six years after it rocketed away from Earth, the plutonium-powered spacecraft has escaped the sun's influence and is now cruising 11 1/2 billion miles away in interstellar space, or the vast, cold emptiness between the stars, NASA said Thursday. And just in case it encounters intelligent life out there, it is carrying a gold-plated, 1970s-era phonograph record with multicultural greetings from Earth, photos and songs, including Chuck Berry's "Johnny B. Goode," along with Beethoven, Bach, Mozart and Louis Armstrong. Never before has a man-made object left the solar system as it is commonly understood.

 

Scientists confirm Voyager 1 probe is in interstellar space

 

Irene Klotz - Reuters

 

Scientists have been debating for more than a year whether NASA's 36-year-old Voyager 1 spacecraft has left the solar system and become the first human-made object to reach interstellar space. By a fluke measurement, they now know definitively it has. "We made it," lead Voyager scientist Edward Stone, from the California Institute of Technology, told reporters on Thursday. The key piece of evidence came by chance when a pair of solar flares blasted charged particles in Voyager's direction in 2011 and 2012. It took a year for the particles to reach the spacecraft, providing information that could be used to determine how dense the plasma was in Voyager's location.

 

See Ya, Voyager: Probe Has Finally Entered Interstellar Space

 

Richard Harris - National Public Radio

 

NASA's two Voyager spacecraft, launched in 1977, have made history in a dramatic fashion by exploring the outer planets: Jupiter, Saturn, Uranus and Neptune. Now one of the vehicles, Voyager I, has made another pioneering leap. It is the first spacecraft to leave the vast bubble of hot gas that surrounds our solar system. At long last, Voyager 1 is now in interstellar space. There was no question that the Voyager spacecraft would someday become the first objects made by human beings to get there. Unknown, though, was whether the probes would still be able to send back the news when they did.

 

NASA confirms Voyager 1 has left the solar system

 

Monte Morin - Los Angeles Times

 

NASA confirmed Thursday that after 36 years of space travel and months of heated debate among scientists, Voyager 1 has indeed left our solar system and had entered interstellar space more than a year ago. "Voyager has boldly gone where no probe has gone before, marking one of the most significant technological achievements in the annals of the history of science," said John Grunsfeld, NASA's associate administrator for the Science Mission Directorate. At a Thursday news conference in Washington, D.C., officials said the belated confirmation was based on new "key" evidence involving space plasma density. The evidence was outlined in a paper published online Thursday in the journal Science.

 

After 36 years, Voyager 1 goes interstellar

 

Joel Achenbach - Washington Post

 

The tireless Voyager I spacecraft, launched in the disco era and now more than 11 billion miles from Earth, has become the first man-made object to enter interstellar space, scientists said Thursday. Interstellar space, scientists now know with certainty, is dense with particles, and the place is literally hissing. Or maybe you could say it's whistling in the dark. "It's almost a pure tone. Like middle C. But slightly varying, like your piano is not quite tuned right," said Donald Gurnett, a University of Iowa physicist who has been working on the Voyager mission most of his adult life. Gurnett is the lead author of a paper published Thursday in the journal Science that provides what seems to be the final, incontrovertible evidence that NASA's Voyager I has crossed into a realm where no spacecraft has gone before.

 

Voyager 1: Humanity's time capsule to the cosmos clears the solar system

 

Pete Spotts - Christian Science Monitor

 

The Federation Starship Voyager it's not. But NASA's Voyager 1 is the next closest spacecraft humanity has, now that the robotic explorer appears to be hurtling through interstellar space. Over the past year, answering the "are we there yet" question has been filled with nos, yeses, and maybes – in no small part because Voyager 1 is exploring, for the first time, a region 11 billion miles away. But after a year of sorting through evidence Voyager has been gathering on its environment, mission scientists announced Thursday that the craft crossed a poorly understood boundary between sun's sphere of influence, or heliosphere, and interstellar space sometime in August 2012.

 

Epic Voyager leaves sun in its rear-view

Launched in 1977 from Brevard, probe heads out into the stars

 

Traci Watson - USA Today

 

For the first time, a human-made object has left the sun's realm behind and ventured into the vast space between the stars, scientists announced Thursday. The record-setting spacecraft is NASA's scrappy Voyager 1, which launched in 1977 from Cape Canaveral and edged into interstellar space on Aug. 25, 2012, according to recent data. The space agency said its now about 12 billion miles from the sun. "We are in a new region of space where nothing has been before," says Voyager project scientist Ed Stone of Caltech.

 

Voyager 1 becomes first human-made object to leave solar system

 

Elizabeth Landau - CNN

 

At the edge of the heliosphere, you wouldn't know by looking whether you left the cradle of humanity behind and floated out into interstellar space. You would just see unfathomably empty space, no matter which side of the invisible line you were on. But scientists now have strong evidence that NASA's Voyager 1 probe has crossed this important border, making history as the first human-made object to leave the heliosphere, the magnetic boundary separating the solar system's sun, planets and solar wind from the rest of the galaxy. "In leaving the heliosphere and setting sail on the cosmic seas between the stars, Voyager has joined other historic journeys of exploration: The first circumnavigation of the Earth, the first steps on the Moon," said Ed Stone, chief scientist on the Voyager mission. "That's the kind of event this is, as we leave behind our solar bubble."

 

Voyager 1 has reached interstellar space

High electron densities show the craft left the Sun's bubble of influence in 2012.

 

Ron Cowen - Nature

 

The debate is over. The venerable Voyager 1 spacecraft has entered the uncharted territory of interstellar space. A team led by Don Gurnett, a space physicist at the University of Iowa in Iowa City, reports compelling evidence that Voyager has exited the heliosphere, the Solar System's protective bubble of charged particles. The findings, published online today in Science1, settle an argument that has raged among members of the Voyager team for more than a year. "This is a milestone," says Ed Stone, a physicist at the California Institute of Technology in Pasadena, who has been the project scientist for the Voyager 1 and 2 spacecraft since 1972, five years before their launch. Voyager 1's entry into interstellar space "ranks with circumnavigating the globe and the first steps on the Moon," says Stone, who was not involved in the latest study.

 

It's Official! Voyager 1 Spacecraft Has Left Solar System

 

Mike Wall - Space.com

 

A spacecraft from Earth has left its cosmic backyard and taken its first steps in interstellar space. After streaking through space for nearly 35 years, NASA's robotic Voyager 1 probe finally left the solar system in August 2012, a study published Thursday in the journal Science reports. "Voyager has boldly gone where no probe has gone before, marking one of the most significant technological achievements in the annals of the history of science, and as it enters interstellar space, it adds a new chapter in human scientific dreams and endeavors," NASA science chief John Grunsfeld said in a statement. "Perhaps some future deep-space explorers will catch up with Voyager, our first interstellar envoy, and reflect on how this intrepid spacecraft helped enable their future."

__________

 

COMPLETE STORIES

 

Spacemen 'flew blind' from space station as sensors failed

 

Agence France Presse

 

The three crew of the International Space Station (ISS) who returned to Earth this week endured a hair-raising descent after their height sensors failed, a Russian cosmonaut revealed on Friday.

 

Pavel Vinogradov said that he and the two other crew of the Soyuz capsule which touched down in Kazakhstan Wednesday had groped their way through the landing after they lost all data about their height from the ground.

 

"There were problems. For some reason after the undocking all our parameters disappeared. Essentially, after the undocking, we flew blind," he said at the Star City cosmonaut training centre outside Moscow, quoted by Russian news agencies.

 

He said that the only data the crew could receive about their approach to the earth -- crucial for knowing when to fire the engines to soften the landing -- came from the salvage team on the ground.

 

He said the rescue teams were able to radio to the crew that they were 300 metres (1,000 feet) and then 100 metres (330 feet) from the ground in the Soyuz capsule, which lands vertically with the help of a parachute after reentering the atmosphere.

 

"I managed to count eight seconds and we touched down very softly," he said, adding that aside from the usual G-forces and jolting "everyone felt normal".

 

Vinogradov, fellow Russian cosmonaut Alexander Misurkin and NASA astronaut Chris Cassidy touched down on the Kazakh steppe on Wednesday morning, in a landing that at the time seemed hitch-free.

 

Russia is currently the only nation capable of transporting humans to the ISS in its Soyuz rocket and capsule system after the withdrawal of the US shuttle.

 

NASA officials talk challenges, and thrills, of capturing an asteroid

 

Deborah Netburn - Los Angeles Times

 

Having trouble getting excited about NASA's planned mission to redirect an asteroid? Maybe William Gerstenmaier can help.

 

"Turn off your logical side and turn on your touchy-feely side, the one you almost never use," Gerstenmaier, associate administrator for NASA's Human Exploration and Operations Directorate, told attendees of an aeronautics and astronautics conference Wednesday in San Diego. "Then jump up and down and do some break-dancing. We're going to grab a space rock and we're going to move it!"

 

Gerstenmaier's comments came at the end of an hour-long panel discussion that included five NASA officials charged with coordinating the agency's plan to capture an asteroid, drag it into lunar orbit and then send a pair of astronauts to meet up with it and collect a sample.

 

The mission, as planned, will unfold over four or five years, said Brian Muirhead, chief engineer at NASA's Jet Propulsion Laboratory in La Cañada Flintridge. It will probably take a year and a half to get a spacecraft to the asteroid, and after its spin has been slowed and it has been bagged, three more years to redirect the space rock into a stable orbit around the moon.

 

Once the asteroid is in lunar orbit, NASA officials said it would take astronauts nine days to get to it, where they would perform two four-hour spacewalks to sample it. Then it's an 11-day trip to get home.

 

"This is a bold mission," said Steve Stich, deputy director of engineering at NASA's Johnson Space Center. "We are talking about sending two crew further than we've ever been in space."

 

The agency's still-developing plan will include a lot of firsts for manned spaceflight, including the first lunar gravity assist during a manned mission, and the first time that a crew will not have the luxury of coming home in a matter of hours or days if something goes wrong, Stich said.

 

"The worst-case scenario we've looked at would take the crew 27 days to come back," he said. "But when I look at Mars, those transit times are nine months, and the way we look at it, this mission is kind of a steppingstone to Mars."

 

The NASA officials emphasized that the asteroid redirect mission is still in the planning phases. Muirhead said the agency hadn't decided whether it would go after a small asteroid about 20 to 30 feet in diameter (like the one in the video above) or instead try to rip a boulder off a larger asteroid and bring the piece back to Earth.

 

When asked what NASA would do after the mission was over and the asteroid was still orbiting the moon, the panel members said they weren't sure.

 

"We could go back to it with a government-led mission, or even down the way open it up to commercial companies," said Stich. "We're still talking about what we want to do."

 

The panelists said they hoped to have made some of the major decisions by the end of the year.

 

"The important thing is we laid out the concept, but we are still open to other ideas and suggestions," said Gerstenmaier.

 

6 Creative Proposals For Deflecting Earth-Threatening Asteroids

 

Elise Ackerman - Forbes

 

During a Congressional hearing last March, Rep. Bill Posey asked NASA Administrator Charles Bolden what the space agency would do if it learned that a large asteroid was three weeks away from striking Earth.

 

"The answer to you is if it's coming in three weeks, pray," Bolden responded. "The reason I can't do anything in the next three weeks is because for decades we have put it off."

 

It wasn't the answer lawmakers wanted to hear. Just one month earlier, an asteroid the size of a large school bus had exploded outside the Russian city of Chelyabinsk, injuring around 1,500 people. The same day another asteroid, this one more than twice as big, buzzed the planet from a height of 17,200 miles, coming closer than communications satellites in geostationary orbits.

 

Within weeks, the White House released a proposed budget for NASA that included $78 million for a manned mission in which astronauts would lasso a small asteroid and tow it into stable orbit around the moon. While autonomous vehicles have rendezvoused with asteroids before, the scope of the asteroid initiative would be unprecedented. NASA is hoping the ambitious project will lead to new scientific discoveries and the development of capabilities to defend the planet against the threat of catastrophic collisions.

 

More than 400 scientists and engineers from around the world sent in proposals for carrying out the asteroid initiative. Over the summer, a team of NASA scientists, engineers and mission planners reviewed the ideas and whittled them down to 96 based on relevance, degree of innovation, the maturity of the development approach and the potential to make the mission more affordable. The proposals, which were released today in abstract form, will be discussed during a public workshop that is scheduled to be held at Houston's Lunar and Planetary Institute from September 30 through October 2.

 

Among the dozens of proposals focusing on improving asteroid observation and classification, constructing asteroid capture systems, affordable flight systems and integrated sensing systems, were six asteroid deflection schemes that stood out.

 

Push-Me/Pull-You. John Brophy, a principal engineer at NASA's Jet Propulsion Laboratory, advocated using a robotic vehicle with an solar electric propulsion technology could deflect asteroids with a diameter of around 50 meters. One possible option, proposed by Tim McElrath, also from JPL, would be to use a similar vehicle as a gravity tractor coupled with mass augmentation. The basic idea is that over time the vehicle's gravitational field would gradually deflect change the orbit of the target asteroid.

 

Impactor collision. Several scientists proposed variants of asteroid pool. Steven Chelsey of JPL called for a type of spacecraft known as an impactor to guide itself into a hyper-velocity impact with an asteroid, thus transferring momentum and changing the asteroid's orbit.

 

Asteroid vs asteroid. Geoffrey Landis, from NASA's Glenn Research Center in Ohio, suggested using "an asteroid to defend against an asteroid." He envisioned bringing a small seven- to ten-meter asteroid into an orbit between the earth and the moon. "From this position, if a threatening asteroid is detected, the trajectory is analyzed, and the defense asteroid can be ejected into a trajectory that intersects the path of the threatening object, thereby deflecting the trajectory into one that does not impact earth," the abstract noted.

 

Ion beam shepherding. David B. Smith of Boeing argued that using a slowly applied force would be superior to a kinetic force used in asteroid pool. He described using an asteroid redirect vehicle equipped with ion thrusters. The concept is that the thrusters would be produce a beam that would be pointed toward the asteroid, gentling prodding it to move in a new direction.

 

The vehicle swarm. Scott Sevick, founder of Prospect Dynamics, a company developing technologies for space mining, envisions a swarm of small satellite vehicles attaching themselves to an asteroid and exerting a "slow push." Alternately, the swam could carry explosive payloads to provide "a high impulse divert."

 

The solar collector option. Robert Adams, a technologist at NASA's George C. Marshall Flight Center, described a process whereby reflective material would be used to collect light and direct it onto an asteroid. "Directing this light onto an asteroid can produce significant vaporization and resulting momentum exchange," the abstract stated. Among the advantages of this method are that it doesn't "radioactively activate or blow holes in the asteroid, like nuclear and kinetic systems" and that it is faster than a gravity tractor which can take tens of years to have an effect.

 

NASA has plan to harvest lettuce in space

 

Robert Stanton - Houston Chronicle

 

Dining aboard the International Space Station can be a bit boring, considering that most of the food is prepared by adding water to the package.

 

But change is on the horizon.

 

This year, NASA plans to harvest a plot of romaine lettuce in zero-gravity under pink LED lights. While the produce should be dining-ready in 28 days, it'll be awhile before the astronauts will be able to eat it.

 

The Vegetable Production System (VEGGIE) Program is NASA's first attempt to grow produce in space that could sustain astronauts.

 

According to the NASA website, "The Vegetable Production System (Veggie) is a deployable plant growth unit capable of producing salad-type crops to provide the crew with a palatable, nutritious, and safe source of fresh food and a tool to support relaxation and recreation. The Veggie provides lighting and nutrient delivery, but utilizes the cabin environment for temperature control and as a source of carbon dioxide to promote growth."

 

In recent years, NASA researchers grew a "crop" of Japanese lettuce called Mizuna, which returned to Earth in space shuttle Discovery.

 

Astronaut gave 'Gravity' advice to Sandra Bullock from space

 

Robert Pearlman - collectSPACE.com

 

Cady Coleman had just finished watching Sandra Bullock in the "The Blind Side" when the actress reached out to her for advice.

 

Coleman, a self-described fan, had never met or spoken to Bullock before and so the contact in the spring of 2011 came out of the blue, or more appropriately, the blackness of outer space.

 

A veteran NASA astronaut, Coleman was about two-thirds of her way through a 5-month stay aboard the International Space Station at the time. Bullock, meanwhile, was set to portray an astronaut in director Alfonso Cuarón's movie, "Gravity" (opening in theaters on Oct. 4).

 

In the highly-anticipated film, Bullock and co-star George Clooney are astronauts on a routine spacewalk when they are violently separated from their space shuttle. Bullock's performance as "Dr. Ryan Stone" needed to be believable if "Gravity" was to convey to audiences the experience of being stranded in space.

 

But it wasn't Cuarón or Warner Brothers Pictures, or even NASA, that brought the real and on-screen space travelers in touch. Instead, it was a chance meeting between their family members.

 

"It was through my younger brother who's in the innovative wine packaging business," Coleman told collectSPACE in her first interview about advising Bullock for the film. "He met Sandra Bullock's sister, who is a chef."

 

The astronaut's and actress' siblings spoke and Bullock's sister asked if Coleman would be amenable to answering some questions from space.

 

As it just so happened, Coleman was watching Bullock's Academy Award-winning performance in "The Blind Side" when the two first connected.

 

"It was really ironic that I'd be watching this movie while running on the [space station's] treadmill and the next day receive an email with her contact information," Coleman said.

 

Aligning the star with space

 

Coleman and Bullock exchanged emails but they agreed it would be nicer if they could talk by phone. That required a bit of space-to-ground coordination.

 

"The big problem is you can't really call us on the station, unless it is an emergency or official," Coleman explained. "But we can call you because we have an internet protocol phone."

 

"So the only way we could really talk was for her to share her phone number and a list of times when we could talk," Coleman said.

 

It was Bullock's first lesson about living in space.

 

"She wanted to know about what it is like to physically live up there and physically move around. 'What would you do with your hands? With your feet? What would be a natural position to work?" How often do you see your crewmates? Where do you meet each other?' It was those kinds of things," Coleman recalled.

 

Bullock, who didn't share much about the movie she was making ("I didn't want to push her to share that," Coleman said), expressed a general interest about life in space.

 

"We did not share any secrets, personal or professional. I don't know if I have any," Coleman remarked. "It was just a genuine exchange of information. She asked really good questions. I came out of it thinking 'I am really glad that this woman is making a movie about what it is like to live in space.'"

 

But it wasn't just helping to make a movie that Coleman relished from her conversation with Bullock.

 

"We talked on the phone for that one long time, which was certainly a nice morale thing for me," the astronaut told collectSPACE. "I'm up there on the station with five guys and to get to talk to somebody who, even instantly on the phone, is so personable, it was like talking to a girlfriend."

 

Coleman and Bullock were only able to arrange one call but Coleman then followed up with e-mailed audio clips, as she and her crewmates thought of more things to tell the actress.

 

"I took the questions that Sandra asked me and I brought them to the dinner table," Coleman said. "My crew and I would talk about what we thought about them or what else we would tell her."

 

"We're working hard up there and the days are really long, so it was pretty neat to have somebody that you've looked up to on the screen from afar to [get in touch]," she said.

 

The 'Gravity' of the situation

 

Coleman doesn't know yet how Bullock applied her advice to the performance.

 

"I haven't actually seen the movie, so I don't know how it turned out," she said.

 

But the astronaut was able to see one of the early movie trailers released by Warner Bros. Pictures. Back on Earth since May 2011, Coleman now directs the "comings and goings" of the robotic spacecraft that resupply the space station.

 

"I have actually only seen one trailer, and that is because it's just such a busy time in the space program right now," she explained.

 

"So I have only seen the one trailer and it is the one where they're on a spacewalk and devastating things happen," Coleman said. "I actually first saw that trailer when I was helping to escort one of the families of our spacewalkers earlier this year, and I just thought, 'Oh my goodness! I just hope his family is not watching this trailer before he goes out on a spacewalk. It sensationalizes a lot of things we do actually very carefully."

 

Coleman said that with her own family she acknowledges the real risks of spaceflight but tries to avoid dwelling on the "what if all four of these things were to happen at the same time" questions.

 

"For something that is dangerous and that we do take very seriously, to see your worst fears realized in 30 seconds is scary," Coleman admitted.

 

But there is a value in such "scares-my-mom" scenes, the astronaut said.

 

"I think the work we do in space is so important and it just can't be done in other places. And I think exploring space and going out further in the universe are things mankind will do no matter what, you just cannot stop it," Coleman said. "Yet, it's very imperative to have the support for that, to have us as a nation or as a world supporting this kind of exploration."

 

"In some ways I will take any type of publicity that shows people out in the world that people can live in space," she said. "So even though it might portray the scarier aspects of exploring, those aspects exist. There is risk in what we do."

 

"Yet the fact that it highlights the real people, including women — smart, strong women that go to space and live up there and work up there — the fact that it would bring attention to that, I think is a valuable thing."

 

Astronaut Does A 'Moon' Walk In The Sea

Better Yet, It's Just One Of Many Recent Underwater Missions

 

Elizabeth Howell - Universe Today

 

The black-and-white tones of this photo evoke a famous Moon walk of 1969, but in reality it was taken in Mediterranean waters just a few days ago.

 

For the "Apollo 11 Under The Sea" project, European Space Agency astronaut Jean-François Clervoy and ESA astronaut instructor Hervé Stevenin took on the roles of Neil Armstrong and Buzz Aldrin, the first two men to walk on the moon during Apollo 11.

 

A major goal was to test the Comex-designed Gandolfi spacewalk training suit (based on the Russian Orlan spacesuits) during the sojourn. The mission was considered the first step (literally and figuratively) to figuring out how Europeans can train their astronauts for possible Moon, asteroid and Mars missions in the decades to come.

 

"The Gandolfi suit is bulky, has limited motion freedom, and requires some physical effort – just like actual space suits. I really felt like I was working and walking on the Moon," Clervoy stated.

 

Water is considered a useful training tool for spacewalk simulations. NASA in fact has a ginormous pool called the Neutral Buoyancy Laboratory. Inside are duplicate International Space Station modules. Astronauts are fitted with weights and flotation devices to make them "float" similarly to how they would during spacewalks.

 

With trained divers hovering nearby, the astronauts practice the procedures they'll need so that it's second nature by the time they get into orbit. (NASA astronaut Mike Massimino once told Universe Today that one thing he wasn't prepared for was how spectacular the view was during his spacewalk. Guess it beats the walls of a pool.)

 

The first tests for the Apollo 11 underwater simulations began at a pool run by Comex, a deep diving specialist in France, before the big show took place in the Mediterranean Sea off Marseille on Sept. 4. The crew members used tools similar to the Apollo 11 astronauts to pick up soil samples from the ground.

 

"Comex will make me relive the underwater operations of [Neil] Armstrong on the moon, but with an ESA-Comex scuba suit and European flag," Clervoy wrote in French on Twitter on June 4, several weeks ahead of the mission.

 

And ESA promises there is more to come: "Further development for planetary surface simulations in Europe will be co-financed by the EU [European Union] as part of the Moonwalk project," the agency wrote.

 

Clervoy isn't the only European astronaut working in water these days. Starting Tuesday (Sept. 9), Andreas Mogensen and Thomas Pesquet joined an underwater lab as part of a five-person crew. Called Space Environment Analog for Testing EVA Systems and Training (SEATEST), it also includes NASA astronauts Joe Acaba and Kate Rubins, as well as Japanese Aerospace Exploration Agency (JAXA) astronaut Soichi Noguchi

 

"The crew will spend five days in Florida International University's Aquarius Reef Base undersea research habitat, conducting proof-of-concept engineering demonstrations and refining techniques in team communication. Additional test objectives will look at just-in-time training applications and spacewalking tool designs," NASA stated on Sept. 6.

 

"We made it to Aquarius n [sic] did our first "spacewalk" today. From the ocean floor to space: Aquanaut to Astronaut. It is quite the adventure," Acaba wrote on Twitter on Sept. 10. He walked twice in space on shuttle mission STS-119 in March 2009.

 

And a few days ago, ESA astronauts Alexander Gerst and Reid Wiseman, both bound for the station in 2014, were doing underwater training in the Neutral Buoyancy Laboratory.

 

HEADING OFF INTO INTERSTELLAR SPACE

 

Voyager 1 finally crosses into interstellar space

 

William Harwood - CBS News

 

Covering nearly a million miles a day, NASA's nuclear-powered Voyager 1 spacecraft, 36 years and 12 billion miles from Earth, has crossed the boundary between the sun's influence and interstellar space, sailing into the vast gulf between the stars to become humanity's first true starship, scientists announced Thursday.

 

"In leaving the (solar system) and setting sail on the cosmic seas between the stars, Voyager has joined the other historic journeys of exploration such as the first circumnavigation of the Earth and the first footprint on the moon," said Voyager project scientist Ed Stone.

 

"This historic step is even more exciting because it marks the beginning of a new era of exploration for Voyager, the exploration of the space between the stars."

 

The sun, its planets, moons, asteroids and comets are embedded in a vast, somewhat teardrop-shaped region, or bubble, in space known as the heliosphere. The heliosphere is defined by the sun's magnetic field and is filled with electrically charged particles blasted away from the sun in all directions -- the solar wind.

 

Voyager 1 reached the boundary of the heliosphere in 2004, a milestone marked by readings showing the speed of the solar wind had dropped below that of sound. But it took another nine years to complete the crossing and move out into interstellar space.

 

The transition actually occurred in August 2012, but an instrument that would have confirmed that failed in 1980, forcing scientists to rely on less direct methods of observation.

 

As it turned out, the sun cooperated, blasting huge clouds of charged particles and magnetic energy in Voyager 1's direction in March 2012. When the particles finally got there 13 months later, they created detectable vibrations in the electrically charged plasma surrounding the spacecraft.

 

After studying those waves, scientists concluded the density of the material was 40 times higher than it would be if Voyager 1 was still in the heliosphere. Reviewing archived data, the science team saw similar, though fainter, vibrations in October and November of 2012. Comparing the events, the team concluded Voyager 1 moved into interstellar space in August 2012.

 

"The atmosphere of the sun expands supersonically, a million miles per hour, creating a huge bubble around all the planets that's called the heliosphere," Stone said. "And inside that bubble, it's filled with the wind from the sun, which is (an electrically charged) plasma, and that plasma carries out from the sun the sun's magnetic field. And that fills this bubble.

 

"Outside this bubble, the plasma comes from the explosions of other giant stars millions of years ago and that plasma carries with it the magnetic field of the galaxy. So that's what's inside. We are now outside."

 

Don Gurnett, leader of Voyager 1's plasma wave experiment at the University of Iowa, announced the milestone in a paper published in Thursday's issue of the journal Science.

 

"We literally jumped out of our seats when we saw these oscillations in our data -- they showed us the spacecraft was in an entirely new region, comparable to what was expected in interstellar space, and totally different than in the solar bubble," Gurnett said in a NASA statement.

 

"Clearly we had passed through the heliopause, which is the long-hypothesized boundary between the solar plasma and the interstellar plasma."

 

Gary Zank, director of the Center for Space Plasma and Aeronomic Research at the University of Alabama-Huntsville, said there was no other explanation for the denser, cooler plasma that Voyager 1 is flying through and "I think we're obliged to conclude we are, in fact, in the interstellar medium."

 

"This is truly a remarkable achievement," he said. "It's very hard for us to comprehend the space age started 55 years ago and in that period we've actually exited the solar system, we've exited the material that's created by the sun and we're in a truly alien environment.

 

"The material in which Voyager finds itself was not created by the sun, it's created, in fact, by our neighboring stars, supernova remnants and so forth. So Voyager in some very real sense is material that's not from the medium in which it finds itself. So we've truly crossed over."

 

Voyager 2 was launched on Aug. 20, 1977, followed 16 days later by Voyager 1 on Sept. 5, 1977.

 

Voyager 1 passed Voyager 2 on the way to Jupiter and flew past the giant planet on March 5, 1979, using its gravity to change course for a Nov. 12, 1980, flyby of Saturn. After beaming back spectacular views of the ringed planet and its enigmatic moon, Titan, the spacecraft headed out of the solar system on a trajectory carrying it above the plane of the planets.

 

Voyager 2 flew past Jupiter on July 9, 1979, and then past Saturn on Aug. 25, 1981. Using the gravity of the ringed planet to properly shape its trajectory, the spacecraft then continued on to Uranus for a Jan. 24, 1986, flyby and then Neptune and one of its moons, Triton, on Aug. 25, 1989.

 

Neptune's gravity bent Voyager 2's trajectory steeply downward, out of the plane of the solar system's planets.

 

Two other spacecraft -- NASA's Pioneer 10 and 11, launched in 1972 and 1973 respectively -- also are departing the solar system. But Pioneer 11 went off the air in 1995 and Pioneer 10 fell silent in 2003 when their nuclear generators could no longer provide enough power.

 

The Voyagers have been beaming back a steady stream of data ever since their planetary flybys, measuring the fields and particles present in the far reaches of the solar system. Now, Voyager 1 and, eventually, Voyager 2 will study interstellar space to learn more about the structure and evolution of the Milky Way.

 

"In a sense, this is only the beginning," Zank said. "Voyager has a rather remarkable capacity to surprise at every turn. We're now going into a completely new environment, it's truly alien, it's not part of the solar system. We've stepped into the galaxy, we're out of our solar environment and what Voyager is going to discover truly beggars the imagination."

 

Voyager 1 is about 11.6 billion miles from Earth and Voyager 2 is roughly 9.5 billion miles out. At those distances, it takes more than 17 hours for 22-watt radio signals, moving at 186,000 miles per second, to cross the vast distance between the spacecraft and the giant antennas on Earth that are needed to collect the data.

 

The radioisotope thermoelectric generators that provide electricity for Voyager 1 and 2 are slowly losing power -- about 4 watts per year -- but they are expected to keep both spacecraft alive through 2020. After that, engineers will begin shutting down science instruments one at a time until the spacecraft eventually falls silent.

 

But their journeys will not end.

 

On its current trajectory, Voyager 1 will pass within about 1.6 lightyears of a star in the constellation Camelopardalis in about 40,000 years. It will take Voyager 2 some 296,000 years to reach a point 4.3 light years from Sirius, the brightest star in Earth's sky.

 

"What does it mean to reach interstellar space?" Stone asked. "Well, first of all, we got there! This is something we all hoped, when we started this 40 years ago, that this would happen. But none of us knew how big this bubble was, and none of us knew anything could last as long as the two Voyager spacecraft.

 

"Certainly luck is an important part of this but wow, when we first saw that data a year ago it was really quite stunning after having been on the way for so many years."

 

NASA: Voyager 1 Probe Has Left the Solar System

 

Alicia Chang - Associated Press

 

NASA's Voyager 1 probe has left the solar system, boldly going where no machine has gone before.

 

Thirty-six years after it rocketed away from Earth, the plutonium-powered spacecraft has escaped the sun's influence and is now cruising 11 1/2 billion miles away in interstellar space, or the vast, cold emptiness between the stars, NASA said Thursday.

 

And just in case it encounters intelligent life out there, it is carrying a gold-plated, 1970s-era phonograph record with multicultural greetings from Earth, photos and songs, including Chuck Berry's "Johnny B. Goode," along with Beethoven, Bach, Mozart and Louis Armstrong.

 

Never before has a man-made object left the solar system as it is commonly understood.

 

"We made it," said an ecstatic Ed Stone, the mission's chief scientist, who waited decades for this moment.

 

NASA celebrated by playing the "Star Trek" theme at a news conference in Washington.

 

Voyager 1 actually made its exit more than a year ago, scientists said. But since there's no "Welcome to Interstellar Space" sign out there, NASA waited for more evidence before concluding that the probe had in fact broken out of the hot plasma bubble surrounding the planets.

 

Voyager 1, which is about the size of a small car, is drifting in a part of the universe littered with the remnants of ancient star explosions.

 

It will study exotic particles and other phenomena and will radio the data back to Earth, where the Voyager team awaits the starship's discoveries. It takes about 17 hours for its signal to reach Earth.

 

While Voyager 1 may have left the solar system as most people understand it, it still has hundreds, perhaps thousands, of years to go before bidding adieu to the last icy bodies that make up our neighborhood.

 

At the rate it is going, it would take 40,000 years to reach the nearest star, Alpha Centauri.

 

Voyager 1's odyssey began in 1977 when the spacecraft and its twin, Voyager 2, were launched on a tour of the gas giant planets of the solar system.

 

After beaming back dazzling postcard views of Jupiter's giant red spot and Saturn's shimmering rings, Voyager 2 hopscotched to Uranus and Neptune. Meanwhile, Voyager 1 used Saturn as a gravitational slingshot to power itself past Pluto.

 

Last year, scientists monitoring Voyager 1 noticed strange happenings that suggested the spacecraft had broken through: Charged particles streaming from the sun suddenly vanished. Also, there was a spike in galactic cosmic rays bursting in from the outside.

 

Since there was no detectable change in the direction of the magnetic field lines, the team assumed the far-flung craft was still in the heliosphere, or the vast bubble of charged particles around the sun.

 

The Voyager team patiently waited for a change in magnetic field direction — thought to be the telltale sign of a cosmic border crossing.

 

But in the meantime, a chance solar eruption that shook Voyager I last spring provided the scientists with the data they needed, convincing them the boundary had been crossed in August of last year.

 

With the new data, "it took us 10 seconds to realize we were in interstellar space," said Don Gurnett, a Voyager scientist at the University of Iowa who led the new research, published online in the journal Science.

 

Not everyone is on board.

 

The new observations are fascinating, but "it's premature to judge," said Lennard Fisk, a space science professor at the University of Michigan and former NASA associate administrator who was not part of the team. "Can we wait a little while longer? Maybe this picture will clear up the farther we go."

 

Fisk was bothered by the absence of a change in magnetic field direction.

 

Voyager 2 trails behind at 9 1/2 billion miles from the sun. It may take another three years before Voyager 2 joins its twin on the other side. Eventually, the Voyagers will run out of nuclear fuel and will have to power down their instruments, perhaps by 2025.

 

Until then, Voyager 1 is "the little spacecraft that could," said mission project manager Suzanne Dodd of the NASA Jet Propulsion Laboratory. "We keep on going."

 

Scientists confirm Voyager 1 probe is in interstellar space

 

Irene Klotz - Reuters

 

Scientists have been debating for more than a year whether NASA's 36-year-old Voyager 1 spacecraft has left the solar system and become the first human-made object to reach interstellar space.

 

By a fluke measurement, they now know definitively it has.

 

"We made it," lead Voyager scientist Edward Stone, from the California Institute of Technology, told reporters on Thursday.

 

The key piece of evidence came by chance when a pair of solar flares blasted charged particles in Voyager's direction in 2011 and 2012. It took a year for the particles to reach the spacecraft, providing information that could be used to determine how dense the plasma was in Voyager's location.

 

Plasma consists of charged particles and is more prevalent in the extreme cold of interstellar space than in the hot bubble of solar wind that permeates the solar system.

 

Voyager 1, now 13 billion miles (21 billion km) from Earth, could not make the measurement directly because its plasma detector stopped working more than 30 years ago.

 

"This was basically a lucky gift from the sun," Stone said.

 

Extrapolating from the measurements, scientists believe Voyager actually left the solar system in August 2012. That summer, the spacecraft radioed back another tantalizing piece of information, showing a huge spike in the number of galactic cosmic rays from outside the solar system and a corresponding decrease in particles emanating from the sun.

 

Scientists had been reluctant to conclude last year that Voyager had reached interstellar space because it was still picking up magnetic field measurements that were very similar to the sun's magnetic field.

 

Computer models had predicted a significant shift in the interstellar magnetic field's alignment.

 

"The magnetic field is still something that puzzles us considerably," said physicist Gary Zank, with the University of Alabama in Huntsville.

 

Scientists now believe the interstellar magnetic field is somehow draped around and twisted by the heliosphere, the bubble of space under the sun's influence.

 

Understanding how that happens is just one of the questions the Voyager team will attempt to figure out while the probe still has power. Voyager 1, and a sister spacecraft Voyager 2, use heat released by the natural decay of radioactive plutonium to generate electrical power for their instruments.

 

'TRULY ALIEN ENVIRONMENT'

 

After 2020, scientists expect they will have to start turning off instruments, until around 2025 when the probes will be completely out of power and fall silent.

 

Voyager 2, which is heading out of the solar system in another direction, has five to seven more years before it reaches interstellar space, said Donald Gurnett, a longtime Voyager scientist at the University of Iowa.

 

"We're in a truly alien environment," Zank said. "What Voyager is going to discover truly beggars the imagination."

 

The two Voyager probes, which were both launched in 1977 to study the outer planets of the solar system, contain gold phonographic records etched with music, greetings, sounds and images from Earth. The project was spearheaded by astronomer Carl Sagan, who died in 1996.

 

With Voyager 1 having left the solar system, the next time it will encounter a star is in 40,000 years, when it flies about 1.7 light years away from a star in the constellation Camelopardalis called AC +79 3888. The spacecraft is traveling nearly 1 million miles (1.6 million km) a day.

 

"Voyager has once again joined the ranks of the great human journeys of exploration," Gurnett said. "This is the first journey into interstellar space."

 

NASA's twin Pioneer spacecraft, launched in the 1970s, also are leaving the solar system, but they have run out of power to relay information back to Earth.

 

The research is published in this week's journal Science.

 

See Ya, Voyager: Probe Has Finally Entered Interstellar Space

 

Richard Harris - National Public Radio

 

NASA's two Voyager spacecraft, launched in 1977, have made history in a dramatic fashion by exploring the outer planets: Jupiter, Saturn, Uranus and Neptune. Now one of the vehicles, Voyager I, has made another pioneering leap. It is the first spacecraft to leave the vast bubble of hot gas that surrounds our solar system.

 

At long last, Voyager 1 is now in interstellar space.

 

There was no question that the Voyager spacecraft would someday become the first objects made by human beings to get there. Unknown, though, was whether the probes would still be able to send back the news when they did.

 

"Most of us felt that we could at least get to Neptune, but we had no idea how much farther it would be," says Edward Stone, who has been the Voyager chief scientist for more than 40 years, is also a physicist at the California Institute of Technology.

 

He and the other scientists have been waiting patiently for the moment when they could say that Voyager has finally entered interstellar space. That's defined as the region outside a huge bubble of hot gas that flows from the sun — the solar wind. That wind dies when it eventually runs into the cooler gas that permeates the galaxy. That's where interstellar space begins.

 

"This is the real deal," Stone says. "Voyager 1 has finally reached interstellar space; the first time a spacecraft has been in the space between the stars."

 

Scientists have been anticipating the event for decades and now believe it occurred a year ago. The instrument on board Voyager 1 that could have notified the team immediately died in 1980.

 

Happily, there is a second instrument on board that measures the environment around the spacecraft. Donald Gurnett, a physics and astronomy professor at the University of Iowa, helped build that instrument back in the 1970s, and he is in charge of it today.

 

But his instrument can only measure the spacecraft's environment when the thin gas surrounding Voyager gets a jolt of energy — say, from the sun.

 

"When you have big explosions on the sun, it sends out a huge shock wave," Gurnett says, and that shock wave perturbs the gas.

 

Last fall, there was a storm on the sun, and Gurnett's instrument picked up the signal. And in May of this year, another solar storm came crashing through. The difference between the two signals was dramatic evidence that Voyager I is now immersed in gases that are colder and denser, outside of the sun's influence. As he reports in the journal Science, Gurnett says that's strong evidence that the probe is in interstellar space.

 

When the Voyagers launched in 1977, nobody knew exactly how far away from Earth this boundary would be.

 

"It's really incredible how far we are. We're three times as far as Pluto — more than that, actually," Gurnett says.

 

Another way to look at the distance: It takes 17 hours for the radio signal to get back to the Earth, traveling at the speed of light. In comparison, it takes about 8 minutes for light to reach Earth from the sun. He says the original Voyager team didn't want to believe it was that far away.

 

"Maybe 30 years ago, people thought it was just beyond the orbit of Jupiter. And I don't think at the time anybody wanted to believe we'd have to go another 20 years before we got there. But that's in fact how it turned out," Gurnett says.

 

Like Gurnett, Edward Stone at Caltech has been waiting for this, as yet another auspicious moment in Voyager's already spectacular career.

 

"It's not only having achieved a major exploration goal, sort of like the circumnavigation of the Earth for the first time, or landing footprints on the moon for the first time, this is the spacecraft to interstellar space," Stone says "That means this is the beginning of a new journey of exploration for Voyager. So rather than ending, we're just starting the next new phase."

 

Stone says there is still a lot to learn, and Voyager 1 probably has another decade of power from its nuclear generator to keep going.

 

NASA confirms Voyager 1 has left the solar system

 

Monte Morin - Los Angeles Times

 

NASA confirmed Thursday that after 36 years of space travel and months of heated debate among scientists, Voyager 1 has indeed left our solar system and had entered interstellar space more than a year ago.

 

"Voyager has boldly gone where no probe has gone before, marking one of the most significant technological achievements in the annals of the history of science," said John Grunsfeld, NASA's associate administrator for the Science Mission Directorate.

 

At a Thursday news conference in Washington, D.C., officials said the belated confirmation was based on new "key" evidence involving space plasma density. The evidence was outlined in a paper published online Thursday in the journal Science.

 

Lead author Don Gurnett, a University of Iowa plasma physicist and a Voyager project scientist, said the data showed conclusively that Voyager 1 had exited the heliopause — the bubble of hot, energetic particles that surrounds our sun and planets — and entered into a region of cold, dark space called the interstellar medium.

 

"When we got that data, I and my colleagues just looked at each other and said, 'We're in the interstellar medium.' It was just that clear to us," Gurnett said.

 

Gurnett calculated that Voyager crossed the edge of the heliosphere, or heliopause, at or around Aug. 25, 2012.

 

"Even though it took 36 years, it's just an amazing thing to me," said study coauthor Bill Kurth, a radio and plasma researcher at the University of Iowa.

 

Scientists had begun to vigorously debate Voyager's whereabouts earlier this year, when it was clear that the probe was being bombarded by an increasing number of galactic cosmic rays and that the number of high-energy particles from inside the heliosphere had plummeted.

 

However, NASA scientists said they could not be certain Voyager had left the solar system until surrounding magnetic fields changed direction. After waiting for that change for more than a year, however, officials conceded that the magnetic field change was not a necessary indicator.

 

"It's a big surprise, and it's another mystery," said Ed Stone, a Voyager project scientist at Caltech and former chief of the Jet Propulsion Laboratory in La Canada Flintridge. "This is not what our models were telling us. We have to address this issue, but right now ... we don't understand."

 

Confusion over Voyager's whereabouts has a lot to do with the failure of one specific piece of equipment, the spacecraft's plasma science experiment, or PLS. The device, which was developed at MIT, measures the electron density of space plasma: ionized gas that is ejected from our sun as well as other stars.

 

Cool plasma, the product of stars that exploded millions of years ago, populates interstellar space and has a high density: about 100,000 electrons per cubic yard of space. Super-heated plasma, like the solar wind that flows from our sun, fills the heliosphere and is much less dense, only about 1,000 electrons per cubic meter, Gurnett said.

 

A functioning PLS would have been able to sense the rising density change as Voyager exited the heliosphere.

 

"The instrument failed in 1980, so the spacecraft is sort of instrument-challenged," Gurnett said. "That's really one of the major failures we've had. There really aren't that many."

 

Voyager does, however, have two plasma wave antennas that stretch from its base in a wide V shape. The antennas, which are connected to a radio transmitter, detect the oscillation, or vibration, of excited plasma particles. The device will convert the oscillations into an audible noise that is recorded on Voyager's vintage eight-track tape recorder.

 

The frequency of the noise is associated with a specific density of plasma. The higher the frequency, the denser the plasma.

 

The only trouble is that something has to excite the plasma for it to "ring," something like a large solar flare. Waiting for a solar flare can take years during a solar minimum (a period of low solar activity).

 

Also, when a flare does occur, it can take as long as a year for the shock wave to reach Voyager 11.6 billion miles away.

 

Fortunately for Voyager scientists, the antennas picked up two long-lasting oscillations. The first was in October and November of 2012 and the second was in April and May of 2013. In both cases, the frequency suggested that the plasma was cold and dense. Voyager was in interstellar space.

 

"It was key evidence," Stone said. "We really needed to measure plasma to know if we were inside or outside the heliosphere. Everything else is more of a proxy."

 

Gurnett and his colleagues arrived at the crossing date of Aug. 25 by extrapolation.

 

Plasma density was increasing in a linear fashion as Voyager moved further from the heliosphere and into the interstellar medium. The frequency measured in the fall of 2012 was 2.2 kilohertz, and by the spring of 2013 it had risen to 2.6 kilohertz. Previous research told Gurnett that the frequency of the radio signal at the crossing point should be 2 kilohertz, and so by plotting each point on a line, he was able to arrive at a date.

 

Scientists are hoping that many gaps in our understanding will be filled in by Voyager 2. The sister spacecraft, which was also launched in 1977, is nearing the edge of the heliosphere via a different path and is expected to encounter interstellar space sometime within the next several years.

 

Unlike Voyager 1, however, Voyager 2 has a fully functioning plasma science instrument and has been sending back density readings throughout its journey.

 

"I think it's going to teach us even more about this region," Stone said.

 

After 36 years, Voyager 1 goes interstellar

 

Joel Achenbach - Washington Post

 

The tireless Voyager I spacecraft, launched in the disco era and now more than 11 billion miles from Earth, has become the first man-made object to enter interstellar space, scientists said Thursday. Interstellar space, scientists now know with certainty, is dense with particles, and the place is literally hissing. Or maybe you could say it's whistling in the dark.

 

"It's almost a pure tone. Like middle C. But slightly varying, like your piano is not quite tuned right," said Donald Gurnett, a University of Iowa physicist who has been working on the Voyager mission most of his adult life.

 

Gurnett is the lead author of a paper published Thursday in the journal Science that provides what seems to be the final, incontrovertible evidence that NASA's Voyager I has crossed into a realm where no spacecraft has gone before.

 

Scientists have long thought that there would be a boundary out there, somewhere, where the million-mile-per-hour "solar wind" of particles would give way abruptly to cooler, denser interstellar space, permeated by charged particles from around the galaxy.

 

That boundary, called the heliopause, turns out to be 11.3 billion miles from the sun, according to Voyager's instruments and Gurnett's calculations.

 

Beyond the boundary, space is — perhaps counterintuitively — much denser with particles. There are 80,000 particles per cubic meter in the region where Voyager I is now, Gurnett said.

 

The sun's hot ejecta — a plasma of charged particles — forms a vast bubble, known as the heliosphere. In the outer regions of the heliosphere, the particles are relatively few and far between, with just 1,000 particles per square meter in some regions, Gurnett said. But the heliosphere has an edge. Voyager I's epochal crossing of the boundary, into the cooler, denser plasma, took place on Aug. 25, 2012, according to the new report.

 

This confirms earlier findings, published in three papers in Science in June, that Voyager I on that date in August 2012 had experienced a sudden drop in solar radiation and a spike in cosmic particles coming from all around the galaxy.

 

But the earlier data from the spacecraft had been somewhat ambiguous. The spacecraft continued to pick up magnetic signals that suggested it was still within the sun's magnetic field. Ed Stone, the chief scientist for Voyager, suggested that Voyager I was flying through a transitional zone.

 

Now, however, scientists have a new set of measurements thanks in large part to a solar flare. On March 17, 2012, the sun ejected a huge mass of particles, and when those solar particles arrived at Voyager more than a year later, on April 9, they triggered oscillations in the charged particles of matter — the plasma — surrounding the spacecraft.

 

From the frequency of those oscillations — essentially the sound of space itself — the scientists could interpret the density of the plasma. That density, much higher than anything registered before in the outer solar system, offered compelling evidence that Voyager I had, in fact, entered the interstellar zone.

 

"For the first time we've actually measured the density of the plasma," Stone said. He said he's convinced by the new data that his spacecraft has fully penetrated interstellar space.

 

"It's great. This is exploration. This is wonderful," said Stone, who has overseen the Voyager project since the early 1970s.

 

The two Voyager spacecraft were launched in 1977. Voyager I flew by Jupiter and Saturn, the gravity of which helped slingshot the spacecraft toward the outer reaches of the solar system. Voyager I is now traveling at 38,000 miles per hour relative to the sun.

 

Voyager II flew near Jupiter and Saturn and then went on to pass by Uranus and Neptune. It is not quite as far from the sun as its sister spacecraft.

 

Although Voyager I is now in interstellar space, it hasn't technically left the solar system. That's because of the Oort cloud — a region of comets in orbit around the sun.

 

"We'll get to the inner edge of the Oort cloud in about 300 years," Stone said. "Of course the spacecraft will not still be transmitting then."

 

The spacecraft draws power from the radioactive decay of Plutonium 238, and Stone thinks the dwindling power supply will force engineers to start turning off instruments in 2020. Voyager I probably will go dark by 2025.

 

Stone said the spacecraft will pass through the far side of the Oort cloud in about 30,000 years.

 

Voyager 1: Humanity's time capsule to the cosmos clears the solar system

 

Pete Spotts - Christian Science Monitor

 

The Federation Starship Voyager it's not. But NASA's Voyager 1 is the next closest spacecraft humanity has, now that the robotic explorer appears to be hurtling through interstellar space.

 

Over the past year, answering the "are we there yet" question has been filled with nos, yeses, and maybes – in no small part because Voyager 1 is exploring, for the first time, a region 11 billion miles away.

 

But after a year of sorting through evidence Voyager has been gathering on its environment, mission scientists announced Thursday that the craft crossed a poorly understood boundary between sun's sphere of influence, or heliosphere, and interstellar space sometime in August 2012.

 

"We made it," enthused the mission's project scientist, Ed Stone, during a NASA briefing. "We're out in front of our own bubble."

 

"It's a remarkable achievement. It's very hard for us to comprehend that the space age started 55 years ago, and in that period we've actually exited the solar system. We're in a truly alien environment," added Gary Zank, director of the Center for Space Plasma and Aeronomic Research at the University of Alabama in Huntsville and a member of the Voyager science team.

 

NASA launched Voyagers 1 and 2 in 1977 to take a grand tour of the solar system's outer planets, which ended in 1989. The two craft were then tasked with traveling to the edge of the heliosphere and beyond to give scientists a better understanding of the sun's interstellar environment and of the structure and processes within the heliosphere at its outermost reaches.

 

Voyager 1 is about 11.6 billion miles from Earth, hurtling toward a star known as AC+799 3888. It's 17.6 light-years away in the constellation Camelopardalis, noted Suzanne Dodd, the project's program manager. Voyager 1 is expected to flit past the star at a distance of about 1 light-year in roughly 40,000 years and then begin its own orbit the Milky Way.

 

Determining Voyager 1's status has required some creative uses of the few instruments that remain active, plus a little help from the sun. The one instrument that would have quickly determined whether this cosmic Elvis had left the building failed in 1980.

 

One piece of evidence came in the form of cosmic rays the spacecraft measured.

 

In May, a team led by Bill Webber, a Voyager veteran and professor emeritus at New Mexico State University in Las Cruces, published a study noting a "sudden and decisive change" in the relative abundance of two types of cosmic rays.

 

One type, formed throughout the galaxy largely by exploding stars, jumped markedly. A second type, formed within the heliosphere from neutral atoms that leak in from interstellar space, fell markedly. This dramatic shift occurred Aug. 25, 2012.

 

But the clincher has come from indirect measurements of the hot ionized gas, or plasma, that Voyager has encountered since April 2012.

 

A research group led by Donald Gurnett, a space-plasma physicist at the University of Iowa in Iowa City and member of the Voyager 1 and 2 science teams, reports that Voyager has entered a region of space where the density of plasma is significantly higher than the plasma it encountered as it traveled through the solar system and into the sun's boundary region.

 

The measured density is remarkably close to the density models have predicted for the cooler plasma in the interstellar medium – the dust and gas found between stars.

 

To make the measurement, the team used an instrument that picks up radio waves plasmas emit when they are disturbed. The disturbance came in the form of a blast from the sun known as a coronal-mass ejection. These typically send billions of tons of plasma hurtling into space at speeds of a million miles an hour or more. Even at Voyager's distance, solar storms delivered enough material to trigger waves in the plasma surrounding the spacecraft as the material approached. The team used the radio signals from the waves – one set from last fall and from this spring – to calculate the changes in plasma density.

 

The results are set to appear in Friday's issue of the journal Science.

 

But as the researchers lacked what they felt would be crucial confirmation of Voyager's break-out: Theory suggested that the craft should detect a roughly 30-degree shift in the orientation of magnetic fields as the magnetic field carried by the sun's plasma yielded to the galaxy's magnetic field.

 

This led the mission's lead researchers to publish three papers in Science in July that collectively put Voyager in a previously unknown region they dubbed the depletion region, but still within the heliosphere. In effect, they said, we're not there yet.

 

But that change in magnetic-field orientation hasn't been detected yet because, in all likelihood, there isn't one, at least one large enough to notice, according to a team led by Marc Swisdak, a researcher at the University of Maryland at College Park.

 

Modeling work Dr. Swisdak and colleagues performed suggested that any change in the orientation magnetic fields will be small, not the easy-to-spot east-west to north-south change researchers had envisioned up to now.

 

And the model indicated that the fields at the absolute boundary, known as the heliopause, are layered and porous, features that were consistent with the data Voyager 1 was beaming back to Earth. Based on its modeling work the team concluded that Voyager 1 cleared the heliosphere July 28, 2012.

 

A formal report of the team's effort appeared in Astrophysical Journal Letters on Sept. 1 and was posted online Aug. 15.

 

While that leaves wiggle room in a precise departure date, the measurements and the modeling study point to a mid-2012 departure for humanity's time capsule to the cosmos.

 

Voyagers 1 and 2 carry recordings that literally have gone gold. Recorded on gold-plated copper disks are photos and sounds from Earth, in addition to music, outlines of male and female humans, and a schematic of where our solar system is located with respect to the rest of the galaxy.

 

Mission officials say the craft can still gather science data for another 13 or 14 years before its power sources run too low to keep even a single instrument running. NASA can track the craft for an additional 10 years if they have it continue to feed engineering data back to Earth.

 

After that, Voyager is on its own.

 

Epic Voyager leaves sun in its rear-view

Launched in 1977 from Brevard, probe heads out into the stars

 

Traci Watson - USA Today

 

For the first time, a human-made object has left the sun's realm behind and ventured into the vast space between the stars, scientists announced Thursday.

 

The record-setting spacecraft is NASA's scrappy Voyager 1, which launched in 1977 from Cape Canaveral and edged into interstellar space on Aug. 25, 2012, according to recent data. The space agency said its now about 12 billion miles from the sun.

 

"We are in a new region of space where nothing has been before," says Voyager project scientist Ed Stone of Caltech.

 

Voyager's feat is a first, but the claim that it has finally tiptoed past the border to interstellar space is not. For a decade, researchers have trumpeted the spacecraft's arrival at one new cosmic boundary after another, and in March scientists presented data arguing that the ship had reached interstellar space in August 2012.

 

NASA promptly poured cold water on the claim. Stone declared it was "critical" to detect certain changes in the magnetic field before concluding that Voyager had departed the heliosphere.

 

That's the enormous blob of solar particles that envelops the planets and shields them from galactic radiation; outside the heliosphere lies the darkspace between the stars.

 

There have been no published reports of the magnetic-field changes that Stone sought as confirmation. Even so, he says he and most of his colleagues think the spacecraft has made it.

 

The clinching evidence is the result of extraordinary good luck: In March, a huge storm on the sun caused vibrations in the soup of charged particles through which Voyager was traveling. An instrument on the spacecraft measured the vibration, and researchers report in this week's Science that the vibration is not at all what they'd expect from the charged particles in the heliosphere. Instead, the vibration is characteristic of a different type of charged particle — those found in interstellar space.

 

The paper's authors dug up records from other such vibration episodes, then put all the data together to infer when Voyager must have hit the edge of the heliosphere. The answer was Aug. 25, 2012 — the same date that Voyager's sensors recorded the near-disappearance of a type of cosmic ray found inside the heliosphere and a dramatic spike in a type of cosmic rays from outside the solar system.

 

"All the facts, the actual data, are consistent with having crossed (into interstellar space) on or around Aug. 25," says the University of Iowa's Donald Gurnett, an author of the Science paper.

 

Aug. 25, 2012, is also the date that NASA downplayed earlier this year. This time, though, the agency is on board. Thanks to the new vibration data, "most of us believe we're in interstellar space," Stone says.

 

The findings provide strong evidence that Voyager has left the solar bubble, but it would be better if the spacecraft had seen the telltale magnetic-field change, says space physicist David McComas of the Southwest Research Institute in San Antonio.

 

"Then it would have been definitive, no questions at all," he says.

 

Other scientists are pretty much convinced already. The vibrations seen by the spacecraft could have been made only in the interstellar medium, says Boston University space physicist Merav Opher.

 

The historic crossing is "extremely dramatic and very romantic," she says, but also "bittersweet. … I wish Voyager 1 could've stayed longer" at the brink of interstellar space. "Such a pity it left. I wanted more data."

 

Voyager 1 becomes first human-made object to leave solar system

 

Elizabeth Landau - CNN

 

At the edge of the heliosphere, you wouldn't know by looking whether you left the cradle of humanity behind and floated out into interstellar space. You would just see unfathomably empty space, no matter which side of the invisible line you were on.

 

But scientists now have strong evidence that NASA's Voyager 1 probe has crossed this important border, making history as the first human-made object to leave the heliosphere, the magnetic boundary separating the solar system's sun, planets and solar wind from the rest of the galaxy.

 

"In leaving the heliosphere and setting sail on the cosmic seas between the stars, Voyager has joined other historic journeys of exploration: The first circumnavigation of the Earth, the first steps on the Moon," said Ed Stone, chief scientist on the Voyager mission. "That's the kind of event this is, as we leave behind our solar bubble."

 

A new study in the journal Science suggests that the probe entered the interstellar medium around August 25, 2012. You may have heard other reports that Voyager 1 has made the historic crossing before, but Thursday was the first time NASA announced it.

 

The twin spacecraft Voyager 1 and 2 were launched in 1977, 16 days apart. As of Thursday, according to NASA's real-time odometer, Voyager 1 is 18.8 billion kilometers (11.7 billion miles) from Earth. Its sibling, Voyager 2, is 15.3 billion (9.5 billion) kilometers from our planet.

 

Voyager 1 is being hailed as the first probe to leave the solar system. But under a stricter definition of "solar system," which includes the distant comets that orbit the sun, we'd have to wait another 30,000 years for it to get that far, Stone said.

 

Another milestone for long after we're gone: The probe will fly near a star in about 40,000 years, Stone said.

 

How do we know?

 

Voyager, currently traveling at more than 38,000 miles per hour, never sent a postcard saying "Greetings from interstellar space!" So whether it has made the historic crossing or not is a matter of controversy.

 

"The spacecraft itself really doesn't know," Stone said. "It's only instruments that can tell us whether we're inside or outside."

 

Further complicating matters, the device aboard Voyager 1 that measures plasma -- a state of matter with charged particles -- broke in 1980.

 

To get around that, scientists detected waves in the plasma around the spacecraft and used that information to calculate density. Vibrations in the plasma came from a large coronal mass ejection from the sun in 2012, resulting in what Stone called a "solar wind tsunami." These vibrations reached the area around Voyager this spring.

 

Measurements taken between April 9 and May 22 of this year show that Voyager 1 was, at that time, located in an area with an electron density of about 0.08 per cubic centimeter.

 

In the interstellar medium, the density of electrons is thought to be between 0.05 and 0.22 per cubic centimeter. The particles of interstellar plasma were created by the explosions of giant stars, and carry the magnetic field of the galaxy, scientists said.

 

Last year, between October 23 and November 27, researchers calculate that Voyager 1 was in an area with an electron density of 0.06 per cubic centimeter. That's still within the interstellar space range, and it means that over time the spacecraft passed through plasma with increasing electron density.

 

The study suggests that the plasma density is about 30 times higher in the interstellar medium than in the heliosphere, which is close to what scientists thought based on other kinds of measurements. The boundary is called the heliopause.

 

When did it happen?

 

Scientists have been using several kinds of measurements to figure out if and when Voyager 1 had reached the interstellar medium.

 

Evidence from particle data had already pointed toward the conclusion that the probe succeeded. In late July and early August of 2012, scientists saw dips in the concentration of particles made in the solar system, and peaks in particles made outside.

 

"If you just looked at that data, you'd think it's pretty clear that we've actually crossed a boundary. We're no longer in the place where the solar system particles are being made, and we're actually out in the interstellar medium," said Marc Swisdak, associate research scientist in the Institute for Research in Electronics and Applied Physics at the University of Maryland. Swisdak was not involved in the new study, but has worked with Voyager data.

 

Magnetic field measurements suggested otherwise. Researchers had expected to see stark changes in magnetic field direction when the probe crossed out of the heliosphere, but that wasn't supported by measurements from the probe.

 

Swisdak and colleagues published a modeling study suggesting that the particle data is more relevant, and that the magnetic field might not change as much as people thought. They proposed a crossing-over date of July 27 -- about a month sooner than the new study.

 

The specific date will likely be debated for some time, Swisdak said. One possible explanation is that if the heliosphere is analogous to an air-conditioned room, Voyager stepped through the doorway into a hot room on July 27. For a month it was in a metaphorical room with a mixture of hot and cold air, and finally entered the truly hot part on August 25.

 

Puzzles still surround the magnetic field at the edge of the heliosphere, Stone said, and "We're going to be prepared to have more surprises."

 

What else is out there?

 

Voyager 1 has only 68 KB of memory on board -- far less than a smartphone, said Suzanne Dodd, Voyager project manager. Scientists communicate with the spacecraft every day.

 

"It's the little spacecraft that could," she said in a NASA press conference.

 

The probe now has a totally new mission, Stone said.

 

"We're now on the first mission to explore interstellar space," he said. "We will now look and learn in detail how the wind which is outside, that came from these other stars, is deflected around the heliosphere."

 

Wind -- made of particles -- from these other stars has to go around the heliosphere the way a water in a stream flows around a rock, Stone said. Scientists are interested in learning more about the interaction between our solar wind and wind from other stars.

 

Natural radioactive decay provides heat that generates enough electricity to help Voyager 1 communicate with Earth. The first science instrument will be turned off in 2020, and the last one will be shut down in 2025, Stone said.

 

Both Voyager probes carry time capsules known as "the golden record," a 12-inch, gold-plated copper disc with images and sounds so that extraterrestrials could learn about us. Let's hope they can build appropriate record players.

 

Voyager 2 will likely leave the heliosphere in about three to four years, Stone said.

 

Its plasma instrument is still working, Stone said, so scientists can directly measure the stellar wind's density, speed and temperature. That also means that when it crosses out of the heliosphere, Voyager 2 will send a clearer signal.

 

At that time, it will join its twin in the vast nothingness between stars that used to be beyond our reach.

 

Voyager 1 has reached interstellar space

High electron densities show the craft left the Sun's bubble of influence in 2012.

 

Ron Cowen - Nature

 

The debate is over. The venerable Voyager 1 spacecraft has entered the uncharted territory of interstellar space.

 

A team led by Don Gurnett, a space physicist at the University of Iowa in Iowa City, reports compelling evidence that Voyager has exited the heliosphere, the Solar System's protective bubble of charged particles. The findings, published online today in Science1, settle an argument that has raged among members of the Voyager team for more than a year.

 

"This is a milestone," says Ed Stone, a physicist at the California Institute of Technology in Pasadena, who has been the project scientist for the Voyager 1 and 2 spacecraft since 1972, five years before their launch. Voyager 1's entry into interstellar space "ranks with circumnavigating the globe and the first steps on the Moon," says Stone, who was not involved in the latest study.

 

The research is based on measurements of the ionized gas, or plasma, through which the spacecraft travels. The frequency at which the plasma vibrates is a sensitive indicator of its electron density, which is predicted to be about 100 times higher in the cold interstellar medium than it is within the warmer bubble of the heliosphere.

 

Gurnett and his collaborators calculate that recent increases in electron density found by Voyager 1 match the predicted density of the interstellar medium. The findings, combined with other spacecraft data, indicate that Voyager 1 left the heliosphere on or about 25 August 2012, when the craft was 121 astronomical units (18 billion kilometres) from the Sun.

 

Gary Zank, a theoretical physicist at the University of Alabama in Huntsville, calls the results definitive. "There is no doubt that we're in interstellar space," he says.

 

Uncharted territory

 

Previous data had suggested that the craft had already left the solar bubble. Evidence included a drop in the number of relatively low-energy cosmic rays that are thought to reside within the Solar System, along with a simultaneous upswing in higher-energy cosmic rays coming from outside the Solar System. However, that shift was not accompanied by a predicted change in the direction of the magnetic field in Voyager's vicinity.

 

Gurnett says that the calculated electron densities should settle the controversy. Those oscillations were serendipitous, the team notes, because some energy source has to disturb the material to generate the vibrations. It takes a solar tsunami — shocks carried into space from eruptions on the Sun — to set the plasma in motion, ringing it like a bell, Stone says.

 

Questions remain about Voyager's journey. The unchanging direction of the magnetic field is still a puzzle, says Stone. It may be a product of a chance alignment between the Solar System's magnetic field and that of the interstellar space, he suggests. It is also possible that the boundary between the heliosphere and what lies beyond is fuzzy, or that the magnetic field carried by the solar wind is linked in some unknown way to that of interstellar space.

 

Stone is careful to say that, although Voyager 1 has exited the heliosphere, it has not left the Solar System. The Oort cloud, a distant reservoir of comets, lies far beyond the solar bubble in interstellar space, but it is part of the Solar System and gravitationally bound to the Sun.

 

But with Voyager 1 firmly outside the heliosphere, "it's a whole new mission", Stone says. Until about 2025, when the craft is expected to run out of its plutonium power source, Voyager 1 can explore the magnetic field, cosmic rays and density of interstellar space. Voyager 2, now 102 astronomical units (15 billion kilometres) from the Sun, is only a few years behind in joining its sister craft in the vastness of space beyond the solar bubble.

 

It's Official! Voyager 1 Spacecraft Has Left Solar System

 

Mike Wall - Space.com

 

A spacecraft from Earth has left its cosmic backyard and taken its first steps in interstellar space.

 

After streaking through space for nearly 35 years, NASA's robotic Voyager 1 probe finally left the solar system in August 2012, a study published Thursday in the journal Science reports.

 

"Voyager has boldly gone where no probe has gone before, marking one of the most significant technological achievements in the annals of the history of science, and as it enters interstellar space, it adds a new chapter in human scientific dreams and endeavors," NASA science chief John Grunsfeld said in a statement. "Perhaps some future deep-space explorers will catch up with Voyager, our first interstellar envoy, and reflect on how this intrepid spacecraft helped enable their future."

 

A long and historic journey

 

Voyager 1 launched on Sept. 5, 1977, about two weeks after its twin, Voyager 2. Together, the two probes conducted a historic "grand tour" of the outer planets, giving scientists some of their first up-close looks at Jupiter, Saturn, Uranus, Neptune and the moons of these faraway worlds.

 

The duo completed its primary mission in 1989, and then kept on flying toward the edge of the heliosphere, the huge bubble of charged particles and magnetic fields that the sun puffs out around itself. Voyager 1 has now popped free of this bubble into the exotic and unexplored realm of interstellar space, scientists say.

 

They reached this historic conclusion with a little help from the sun. A powerful solar eruption caused electrons in Voyager 1's location to vibrate signficantly between April 9 and May 22 of this year. The probe's plasma wave instrument detected these oscillations, and researchers used the measurements to figure out that Voyager 1's surroundings contained about 0.005 electrons per cubic inch (0.08 electrons per cubic centimeter).

 

That's far higher than the density observed in the outer regions of the heliosphere (roughly 0.0001 electrons per cubic inch, or 0.002 electrons per cubic cm) and very much in line with the 0.006 electrons per cubic inch (0.10 electrons per cubic cm) or so expected in interstellar space.

 

"We literally jumped out of our seats when we saw these oscillations in our data — they showed us that the spacecraft was in an entirely new region, comparable to what was expected in interstellar space, and totally different than in the solar bubble," study lead author Don Gurnett of the University of Iowa, the principal investigator of Voyager 1's plasma wave instrument, said in a statement.

 

It may seem surprising that electron density is higher beyond the solar system than in its extreme outer reaches. Interstellar space is, indeed, emptier than the regions in Earth's neighborhood, but the density inside the solar bubble drops off dramatically at great distances from the sun, researchers said.

 

Calculating a departure date

 

The study team wanted to know if Voyager 1 left the solar system sometime before April 2013, so they combed through some of the probe's older data. They found a monthlong period of electron oscillations in October-November 2012 that translated to a density of 0.004 electrons per cubic inch (0.006 electrons per cubic cm).

 

Using these numbers and the amount of ground that Voyager 1 covers — about 325 million miles (520 million kilometers) per year — the researchers calculated that the spacecraft likely left the solar system in August 2012.

 

That time frame matches up well with several other important changes Voyager 1 observed. On Aug. 25, 2012, the probe recorded a 1,000-fold drop in the number of charged solar particles while also measuring a 9 percent increase in fast-moving galactic cosmic rays, which originate beyond the solar system.

 

"These results, and comparison with previous heliospheric radio measurements, strongly support the view that Voyager 1 crossed the heliopause into the interstellar plasma on or about Aug. 25, 2012," Gurnett and his colleagues write in the new study.

 

At that point, Voyager 1 was about 11.25 billion miles (18.11 billion km) from the sun, or roughly 121 times the distance between Earth and the sun. The probe is now 11.66 billion miles (18.76 billion km) from the sun. (Voyager 2, which took a different route through the solar system, is currently 9.54 billion miles, or 15.35 billion km, from the sun.)

 

Magnetic-field mystery

 

Mission scientists have long pegged Voyager 1's departure from the solar system on the observation of three phenomena: a big drop in solar particles, a dramatic jump in galactic cosmic rays and a shift in the orientation of the surrounding magnetic field.

 

Voyager 1 has measured the first two changes, as noted above, but not the third; the magnetic field is stronger than it used to be in the probe's location, but it hasn't changed direction.

 

This key point has led NASA and the mission team to proceed with caution. For example, they have held off on making any big announcements, despite several recent studies by outside researchers — including one published last month— suggesting that Voyager 1 entered interstellar space in July or August 2012.

 

But the new electron-density measurements have convinced Voyager mission scientists that the probe is, indeed, beyond the solar bubble.

 

After all, magnetic-field measurements were always regarded as a proxy for observations of electron density, said Voyager chief scientist Ed Stone, a physicist at the California Institute of Technology in Pasadena.

 

"The solar wind carries the solar magnetic field with it, and the interstellar wind carries the galactic magnetic field with it," Stone, who is not an author of the new Science paper, told SPACE.com. "Once we got the plasma data itself in interstellar space, we knew we must have left the bubble."

 

(Voyager 1 launched with an instrument designed to measure plasma density directly, but it failed in 1980, forcing the team to get more creative.)

 

Scientists need a better understanding of the complex interface between the solar and galactic magnetic fields to figure out why Voyager 1 hasn't measured the predicted change in field direction, Stone said.

 

"What we need to do now is go back and look more carefully at the models of that interaction," he said.

 

Voyage of exploration

 

The Voyager mission has racked up a series of discoveries over the last 36 years, revealing key insights about the giant planets and their moons, as well as conditions at the edge of the solar system.

 

The spacecraft's arrival in interstellar space could bring many more exciting finds, the researchers said.

 

"Every day we look at data, we know we're looking at data that no one has seen before and is in a region where nothing has ever been before," Stone said. "I think we're all looking forward to learning a lot in the years ahead."

 

Voyager 1 could keep beaming data home for a while, provided nothing too important breaks down. The spacecraft's declining power supply won't force engineers to shut off the first instrument until 2020, mission scientists have said. All of Voyager 1's science gear will probably stop working by 2025.

 

END