Keep the shuttle flying: Fwd: Philae comet lander bounced into shadows, raising battery fears

Sent from my iPad

Begin forwarded message:

From: "Gary Johnson" <gjohnson144@comcast.net>
Date: November 13, 2014 7:19:49 PM CST
To: "Gary Johnson" <gjohnson144@comcast.net>
Subject: FW: Philae comet lander bounced into shadows, raising battery fears

Philae comet lander bounced into shadows, raising battery fears
11/13/2014 04:30 PM
By WILLIAM HARWOOD
CBS News

When the Philae spacecraft landed on Comet 67P/Churyumov-Gerasimenko Wednesday, the anchors needed to hold it down in the feeble gravity failed to fire and the lander bounced back into space, soaring more than a half mile above the nucleus before hitting the ground a second time more than a half mile away, engineers said Thursday.

And then it bounced again, telemetry indicates, finally coming to rest near the base of what appears to be a jagged cliff, with Philae tilted to one side in a jumbled pile of dusty rocks. Two of its three landing legs are in contact with the surface and one extends unsupported, up into space.

Apparently none the worse for its wild ride, Philae is still communicating with its parent spacecraft -- Rosetta -- and it appears to be generally healthy with most of its science instruments operating normally.
An image of the surface of Comet 67P/Churyumov-Gerasimenko just beyond the Philae lander, taken after the spacecraft came to a rest two bounces away from its original touchdown point. (Credit: ESA)

But the spacecraft ended up in heavily shadowed terrain -- engineers do not yet know exactly where -- and its solar cells are only receiving an hour and a half of sunlight each day instead of the six or seven hours needed to recharge its batteries for extended operation. If nothing is done to improve its orientation, Philae likely will exhaust its battery and shut down sometime during the next few days.

"The lander from a systems point of view is operating nominally," said Koen Geurts, Philae operations manager with DLR, the German space agency. "What we need to understand now is what does this position mean for us? We're not standing parallel to the surface. We're seeing how we can modify the planned nominal operations to cope with this non-nominal position that we're in."

The spacecraft is equipped with two batteries and solar cells for recharging. The batteries were fully charged when Philae was released from Rosetta Wednesday, with enough power for about 60 hours of normal operation.

In its current location and orientation, "we see that we get less solar power than we planned for at the nominal landing site," Geurts said. "We're receiving about one-and-a-half hours of sunlight with respect to the six or seven that we were aiming (for). This, of course, has an impact on our energy budget and our capabilities to conduct science for an extended period of time."

He did not provide an estimate for how long the Philae might operate in its current orientation, saying only that "we are calculating what this means for the near future. At the moment, I cannot say much. Unfortunately, this is not a situation we were hoping for."

Engineers are assessing a variety of options that might be possible to move Philae or improve its orientation with respect to the sun. Redeploying its landing legs in the comet's feeble gravity, for example, likely would cause the lander to move, but Ulemac said nothing like that would be attempted until engineers get a much better understanding of the possible consequences.

New images downlinked from Philae overnight were assembled into a panorama providing a 360-degree view of the terrain around the lander. Much of it is shadowed with few visible details, but several frames provide sharply focused views of the surface, revealing fractured rocks and dust.

Another instrument aboard the lander that was designed to probe the comet's hidden interior was used to get a sense of where Philae ended up after its bouncing descent. It appears the spacecraft may be near the wall of a huge crater on one end of the comet. Engineers expect to pinpoint the location soon and high-resolution views from Rosetta's OSIRIS camera might have captured a view of Philae in flight, during its initial two-hour bounce.

New OSIRIS images were release Thursday showing Philae's departure from Rosetta and one dramatic shot showing the lander about an hour before touchdown, appearing as a faint speck of light in the black of space with the rugged comet looming to one side.
The OSIRIS camera aboard ESA's Rosetta spacecraft captured this image of the Philae lander (circled) about an hour before touchdown on 67P/Churyumov-Gerasimenko. (Credit: ESA)

Philae's improbable landing was a surprise to just about everyone involved in the project.

Because 67P/Churyumov-Gerasimenko's gravity is roughly 100,000 times weaker than Earth's, Philae was equipped with three systems to make sure it didn't bounce off at touchdown.

Each of its three landing legs featured ice screws designed to bore into the crust of the nucleus for extra grip. In addition, two harpoons were designed to fire into the surface while a cold-gas thruster on top of the spacecraft pushed down to counteract the recoil from the harpoons.

But none of the anchors worked, and Philae bounced off the comet after touching down almost dead center in the intended landing zone. Stephan Ulemac, the Philae landing team director, said Wednesday that Philae apparently bounced once and landed twice.

"We landed three times," he said Thursday. "Now we know the first jump (lasted) about two hours, one hour and 50 (minutes). We assume we came in with about 1 meter per second (2.2 mph velocity) then we rebounced with about 38 centimeters per second (0.85 mph velocity)."

Philae reached an altitude of about six tenths of a mile -- more than 3,000 feet if the estimates are correct -- landing again about six-tenths of a mile away. The second bounce, at a rebound velocity of about .07 mph, lasted just seven minutes or so with Philae coming to rest near the base of a cliff of some sort.

"After our first touchdown signal yesterday, we saw immediately that something was not nominal because our system data was indicating the lander was still moving," Geurts said. "And this could only indicate we were not standing on the comet's surface. Fortunately, the comm link between Rosetta and Philae remained intact. We continuously saw the lander kept rotating.

"We observed this for about two hours, and we saw a change in this and we saw the rotation stopped. This was a very good signal because the rotation could only stop by touching the comet again. So for us, this was a clear indication we were at the comet."

But the distance and duration of the first bounce "makes it difficult to find out where we are now," Ulemac said. "We know very well where we touched down the first time. It was a huge leap, then we had another very small jump of about 3 centimeters per second for seven minutes. Now we are in a configuration as you've seen in the images here."

Only instruments that operate passively, without imparting any motion due to mechanical movements or deployments, are currently operating. Philae's drill, for example, designed to penetrate the surface of the nucleus and extract soil samples, remains stowed pending additional analysis.

"This evening, we should re-establish (communications) and then we will upload the newest science sequence we want to operate on the comet," Ulemac said. "Since we do not really know how we are landed, since we are not anchored, somehow just with the weight of the lander, we need to be very careful about activating mechanisms."
In this composite, an image of the Philae lander is superimposed on a panorama shot by the spacecraft showing its immediate surroundings. Toward the top of the image is black sky, indicating that side of the lander is tilted up. (Credit: ESA)

The Rosetta spacecraft, meanwhile, continues operating in near flawless fashion, collecting science data and helping with the search for Philae. Unlike the lander, which was never expected to operate more than a few months, Rosetta will fly in tandem with 67P/Churyumov-Gerasimenko for the next year and a half, recording how the comet changes as it nears the sun and then recedes.

About 80 percent of the science expected during the mission will come from Rosetta's instruments with the rest coming from Philae.

Jean-Pierre Bibring, a lead scientist with the Philae project, urged reporters not to over-emphasize the lander's current difficulties.

"What's really impressive is not really the degree of failure that we encountered but the degree of success we had here," he said. "At this point, I think the message is certainly not to say 'well, they are here now, but they should have been elsewhere.' It's amazing where we are, we landed! We analyzed a lot of things already, in 20 hours, it's amazing what we've been doing or what we'll be doing by the end of this day. It's really tremendous.

"We are really at the limit of what humankind could do 20 years ago, and are still capable of doing now. But please do not put the emphasis on the failure of the system. It's gorgeous where we are."

© 2014 William Harwood/CBS News

Researchers race to collect comet data from Philae
November 13, 2014 by Stephen Clark
Artist's concept of the Philae lander. Credit: ESA
DARMSTADT, Germany — Comet scientists planned to send up new orders to Europe's Philae lander Thursday to kick off a second day of research after the probe endured a jumpy touchdown on comet 67P/Churyumov-Gerasimenko.
Time is of the essence because the oven-sized landing craft is facing a power crunch.
The lander bounced across the comet's tortured landscape before coming to rest near a cliff that blocks sunlight from reaching Philae's solar panels, meaning the craft's power generation system may be unable to recharge its batteries.
Officials said Thursday the Philae might be on its side, with two of its landing legs contacting the comet's surface and another off the ground.
The first images from Philae's CIVA camera system — made up of seven micro-cameras in a ring around the lander — appeared to show fragments of rock illuminated by the sun on one side of the probe and the sky on the other side.
Philae's landing legs also appear in the images.
"We saw both something that man built — the lander — you see the foot there, and something that nature built 4.6 billion years ago, which is a comet essentially preserved as it was at that time, containing all the history that we're trying to look at," said Jean-Pierre Bibring, Philae's chief scientist and head of the CIVA camera team from Institut d'Astrophysique Spatiale in Paris. "We have no idea what is around, or whether or not what is black is just shadow or open sky."
Rosetta's lander Philae has returned the first panoramic image from the surface of a comet. The view, unprocessed, as it has been captured by the CIVA-P imaging system, shows a 360º view around the point of final touchdown. The three feet of Philae's landing gear can be seen in some of the frames. Superimposed on top of the image is a sketch of the Philae lander in its current configuration. Credit: ESA/Rosetta/Philae/CIVA.
Bibring said many scientists expected the comet's surface to be powdery, allowing the lander to settle instead of rebounding back into space.
"It's not a powder, it's a rock, so it's like a trampoline," Bibring said. "You go there and it ejects you immediately afterwards."
Officials have not pinpointed the lander's location on the comet.
Stephan Ulamec, leader of the Philae team at DLR — the German Aerospace Center — said the landing craft could have bounced up to a kilometer (0.6 miles) off the comet before coming back down a kilometer away from the mission's intended touchdown site.
"We have a better understanding now of how we got there, but we still do not really know where (the lander is located)," Ulamec said.
According to Ulamec, the next opportunity to contact Philae will be after 1900 GMT (2 p.m. EST) Thursday.
Ground teams based at the European Space Operations Center here, the lander control center in Cologne, Germany and the Philae science team headquarters in Toulouse, France, will uplink commands to the probe Thursday night through the Rosetta orbiter, which released Philae for its seven-hour descent Wednesday.
This image from Rosetta's camera, taken in September, shows the place Philae first landed before bouncing twice and finally coming to rest about a kilometer away. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA.
Ulamec and Bibring said the command upload Thursday night will likely include orders to deploy a boom designed to measure the temperature of the comet's surface and an X-ray spectroscopy instrument to study the chemical composition of material around Philae's landing site.
Controllers will also tell Philae to take pictures for another panorama after adjusting the camera's exposure settings in hopes of improving on the imagery released Thursday.
"We need to be very careful about activating mechanisms," Ulamec said.
The extension of Philae's temperature boom could nudge the lander out of its current position. The comet's feeble gravity field — one hundred thousand times less than Earth — means the lander, which weighed about 220 pounds on Earth, weighs as much as a paperclip after landing.
Officials want to see how the deployment of instrument arms Thursday night changes the lander's orientation.
"We will be able to see whether this has modified our position," Bibring said.
Plans to use Philae's drill, which is supposed to bore nearly a foot into the comet nucleus, pose more problems.
"We are hesitant in the next hours or day to activate the drill because drilling without being anchored and without knowing how we are on the surface is dangerous," Ulamec said. "We may just tip over our lander."
The drill is designed to extract a core sample and deliver the soil to a miniaturized laboratory on the lander for analysis. Scientists are trying to find out if the comet contains ice made of water similar to that on Earth, and they are looking for signs of organic molecules like amino acids, the building blocks of life.
Comets may have seeded Earth with water and organics, allowing life to spring up billions of years ago.
Bibring said such measurements are "fundamental" to the Philae mission, but some of the lander's sensors could gather data in "sniffing mode" not requiring direct contact with the material.
Philae's instrument package. Credit: ESA
"Of course, we want to drill, but we have to secure the drill," Bibring said.
Ulamec dismissed discussion — at least for now — of trying to fire the lander's harpoons, which failed to engage during Philae's descent Wednesday to anchor the spacecraft to the comet.
Momentum from firing the harpoons — assuming they still work — could propel the lander out of its current location into a more favorable place for exposure to sunlight, which could generate power to keep Philae from freezing.
Philae's power crisis could drain the lander's primary and secondary batteries by this weekend.
"Whether this will be able to make it to tomorrow evening, Saturday or Sunday, we don't know," Bibring said. "It's only when it fails do you know how much time you had."
In a press briefing from Philae's science operations center in Toulouse earlier Thursday, officials estimated the lander had between 50 and 55 hours of power left in its batteries.
The lander was designed to operate for more than two days on battery power, then recharge its batteries with solar energy for an extended mission that could last until March, when the probe is expected to overheat as the comet nears the sun.
"We see that we get less solar power than we planned for at the nominal landing site," said Koen Geurts, Philae's technical manager at the lander control center in Cologne. "We receive about 1.5 hours of sunlight with regard to the 6 or 7 (hours) that we were aiming for. Of course, (this) has an impact on our energy budget and our capabilities to conduct science for extended period of time afterwards."
Bibring said Philae carries 40 kilograms (88 pounds) of equipment that must be heated to at least minus 50 degrees Celsius (minus 58 degrees Fahrenheit) to keep it from freezing. If the hardware gets too cold, the lander will not be able to wake back up again.
"We need energy to survive," Bibring said. "There is a minimum energy to do that — a few watts."
In the long-term mission, Philae was expected to wake up for intermittent research observations and hibernate to recharge its batteries.
"We are calculating now what this means for the near future … but unfortunately this is not the situation that we were hoping for," Geurts said.
With the future of Philae uncertain beyond the weekend, scientists are focused on the short-term.
"We want to pack in as much as we can now," Bibring said.
© 2014 Spaceflight Now Inc.

Philae Spacecraft Landed 3 Times on Speeding Comet: See Its First Photos
by Miriam Kramer, Space.com Staff Writer | November 13, 2014 11:41am ET

The European Space Agency's Philae probe landed on the Comet 67P/Churyumov-Gerasimenko not once or twice, but three times, when its anchor system failed to fire. But despite that, the probe is healthy and beaming back stunning photos of its new home.
European Space Agency (ESA) officials still aren't exactly sure where the Rosetta spacecraft's lander, called Philae, ended up after bouncing on the surface of Comet 67P/C-G twice before finally settling down. At the moment, officials think the lander — which was released down to the comet from the Rosetta orbiter Wednesday (Nov. 12) — is in a potentially precarious position away from its initial touchdown site. The new comet surface photos from Philae, released by ESA today, show the lander shadowed by what appears to be some kind of cliff.
"It's amazing where we are," Jean-Pierre Bibring, Rosetta mission scientist, said during an ESA news conference today (Nov. 13). "We landed … Please do not put the emphasis on the failure of the system. It's gorgeous where we are." [Rosetta Comet Landing: Complete Coverage]
This photo from the European Space Agency is the Philae lander's view of its landing site on Comet 67P/C-G's surface. Image release Nov. 13, 2014.
Credit: ESA/Rosetta/Philae/CIVA
View full size image
The European Rosetta spacecraft's Philae lander aims to be the first probe ever to safely land on a comet. Here's how to land on a spinning ice mountain in space.
Credit: By Karl Tate, Infographics Artist
View full size image
The new photos represent the first-ever pictures taken by a probe from the surface of a comet. Philae landed on the comet as the icy object, the lander and Rosetta were speeding across deep space at more than 11,000 mph (17,702 k/h).
Philae's harpoon system, meant to fire just after landing, did not deploy when Philae got to the comet's surface, and officials with the mission are not sure if they want to try re-firing them now. Officials are worried that, if the harpoons don't fire properly, they might cause the spacecraft to jump again.
Mission controllers now think that Philae could have bounced as far as 1 kilometer (0.6 miles) into space before making its second landing. The spacecraft then bounced away from the surface again on a shorter jump before coming to a rest in its current position, officials said today.
Officials are planning on trying to find Philae's spot on the comet's surface in images its mothership Rosetta took from the comet's orbit.
One of Philae's three landing legs could be off the surface of the comet, so mission operators are still trying to understand exactly how the lander is positioned on the comet's surface. ESA officials still aren't sure whether Philae's drill instrument (designed to investigate the composition of the comet's surface) will work properly in the lander's current position.
"We are also hesitant to, in the next hour or days, to activate the drill because drilling without being anchored, and without knowing how you are [positioned] on the surface, is dangerous," Stephan Ulamec, Philae lander manager at the DLR German Aerospace Center, said during the news conference. "We might just tip over our lander."
This first panorama from the surface of Comet 67P/Churyumov–Gerasimenko was captured by the Philae lander on Nov. 12, 2014 after its historic landing during the European Space Agency's Rosetta mission. ESA released the image Nov. 13 to show its first glimpses ever from the surface of a comet.
Credit: ESA/Rosetta/Philae/CIVA
View full size image
Scientists also think that the lander is not getting enough sunlight from its currently shadowed position, and that could reduce the life of the lander on Comet 67P/C-G's surface. Instead of the 6 to 7 hours of sunlight expected at the first landing site, Philae is only receiving about 1.5 hours of sunlight on its solar panels in the new spot, ESA officials said.
But scientists working with the mission are still hopeful.
"Even if we think the mission ends because the first science sequence may end, and the batteries are low, the lander is not necessarily dead," Ulamec said. It's possible that the lander could go into hibernation mode and wake up again when it gets more sunlight, but it's also possible that might not happen, he added.
The Rosetta spacecraft and Philae lander arrived at Comet 67P/C-G in August 2014 after launching to space in 2004. Rosetta is expected to stay with the comet, studying it until December 2015.
Copyright © 2014 TechMediaNetwork.com All rights reserved.