Fwd: U.S. EVA-24 Begins

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From: "Gary Johnson" <gjohnson144@comcast.net>
Date: December 21, 2013 8:20:01 PM CST
To: "Gary Johnson" <gjohnson144@comcast.net>
Subject: FW: U.S. EVA-24 Begins

Realtime coverage of U.S. EVA-24

12/21/2013 07:26 AM 

By WILLIAM HARWOOD
CBS News

Astronauts Rick Mastracchio and Mike Hopkins switched their spacesuits to battery power early Saturday, kicking off the first in a series of spacewalks to replace a refrigerator-size ammonia pump assembly aboard the International Space Station in a high-stakes attempt to restore a critical coolant loop to normal operation.

Floating in the station's Quest airlock module, the astronauts began the planned six-and-a-half-hour excursion at 7:01 a.m. EST (GMT-5) as the space station sailed 260 miles above the Atlantic Ocean approaching Africa.

"Quite a view," Hopkins marveled as he floated outside the airlock to begin his first spacewalk.

"Yeah, watch that first step," joked Mastracchio, making his seventh EVA.

Engineers are trying to figure out how to fix a balky flow control valve used to regulate the temperature of ammonia coolant in an external thermal control system loop aboard the International Space Station.The valve in question is located inside a pump module, noted above, that is part of coolant loop A, one of two critical systems used to keep station components from over heating. (Credit: NASA)

For identification, Mastracchio, call sign EV-1, is wearing a suit with red stripes and using helmet camera No. 20. Hopkins, EV-2, is wearing an unmarked suit with helmet camera No. 18. This is the 175th spacewalk devoted to station assembly and maintenance since construction began in 1998 and the ninth so far this year.

Hopkins' spacesuit -- serial No. 3011 -- is the same one that suffered a water leak during a July spacewalk, flooding the helmet of European Space Agency astronaut Luca Parmitano in a frightening emergency that forced the crew to stop work and beat a hasty retreat to the safety of the station's airlock.

An exhaustive investigation blamed the leakage on contamination that clogged one or more filters in the suit's cooling water recirculation system. While the root cause of the contamination has not yet been determined, the suspect hardware in suit No. 3011 was replaced and engineers are confident the problem has been resolved.

Just in case, the astronauts positioned water-absorbing pads behind their heads, where the water entered Parmitano's helmet in July, and used velcro to secure snorkel-like plastic tubes within easy reach of their mouths. The tubes extend down into the body of the suit, giving the spacewalkers an unobstructed source of air if water somehow makes it into either helmet.

The water-absorbing pads and snorkels should provide more than enough time to reach the safety of the station's airlock if another leak does, in fact, develop.

The spacewalks were ordered after a critical valve in one of the space station's two coolant loops malfunctioned last week, resulting in lower-than-allowable temperatures.

While coolant loop A remained partially operational, flight controllers were forced to shut down a variety of systems in the station's forward modules, including experiment hardware, to keep those systems from over heating. Coolant loop B remained fully functional.

Engineers attempted to resolve the problem using a software patch to precisely control the position of another valve in the coolant system, and thus the temperature of the ammonia in loop A. But NASA managers ultimately opted for a series of spacewalks to replace the ammonia pump module where the suspect flow control valve is located.

The pump module in question was installed during three 2010 spacewalks after the pump in the original assembly broke down, taking out coolant loop A in its entirety. This time around, the loop A pump is working normally, cooling components mounted outside the station's habitable modules. But the faulty flow control valve is preventing the loop from cooling components mounted inside the habitable compartments.

The loop A pump module is mounted on the right side of the station's main solar power beam in truss segment S1.

Mastracchio and Hopkins plan to replace the 780-pound assembly with one of three spares mounted on external storage platforms. During Saturday's spacewalk, they plan to set up the tools they'll need, open insulation blankets and disconnect four ammonia lines from the balky pump unit.

The first two ammonia lines to be disconnected - M3 and M4 - will be connected to a "jumper box" that will prevent the loop A coolant system from over pressurizing during temperature swings in orbit. With the jumper box hooked up, the astronauts will disconnect the other two ammonia lines, along with five electrical connectors.

During a second spacewalk Monday, the astronauts plan to remove the faulty pump assembly and temporarily stow it on a nearby mounting fixture. The replacement pump module then will be installed in its place and the astronauts will re-connect the electrical lines.

During a third spacewalk Christmas day, Mastracchio and Hopkins will re-connect the fluid lines and close out the replacement module. They also will move the old pump assembly to the same storage pallet where the replacement pump was mounted.

If the work goes smoothly, it may be possible to complete the pump module swap out in two spacewalks. But during the 2010 replacement work, Douglas Wheelock and Tracy Caldwell-Dyson ran into problems getting the ammonia lines disconnected and a third spacewalk was required.

Given their past experience, NASA planners say there's a good chance the Christmas day spacewalk will be needed and time has been set aside just in case.

Here is a timeline of major spacewalk tasks planned for Saturday (in EST and event elapsed time; best viewed with fixed-width font):

EST........HH...MM...EVENT

07:01 AM...00...00...Suits to battery power (spacewalk begins)
07:06 AM...00...05...Egress/setup

07:46 AM...00...45...EV1: Robot arm (SSRMS) setup
.....................Install WIF adapter
.....................Install portable foot restraint
.....................Safety tether swap to SSRMS
07:46 AM...00...45...EV2: Failed pump module preps

.....................Open large ORU bag; stage crewlock bag 1
.....................Stage fish stringer
.....................Open and restrain pump module insulation shroud
.....................Release TA clamps from pump module fluid lines

.....................Assist EV1 with spool positioning device (SPD) removal
08:26 AM...01...25...EV1: Failed pump module preps
.....................Remove SPDs
08:56 AM...01...55...EV1: SSRMS ingress
08:56 AM...01...55...EV2: Ammonia line quick disconnect demate (assist EV1)

09:06 AM...02...05...EV1: QD demates (M4, M3,M1,M2)
.....................Close/demate M4,M3
.....................Install pump module jumper
.....................Attach insulation to jumper
.....................Close/demate M1,M2

.....................Install insulation cover over M1,M2
11:41 AM...04...40...EV2: Prep failed pump module for removal
.....................Demate electrical connectors (5)
12:11 PM...05...10...EV2: Spare pump module prep

.....................Open pump module insulation
.....................Remove tape/velcro from pump module handrails
12:21 PM...05...20...EV1: Egress SSRMS
12:41 PM...05...40...Clean up/ingress
.....................EV1 close and stow large ORU bag on CETA cart

01:26 PM...06...25...Pre-repress
01:31 PM...06...30...Spacewalk ends

Going into Saturday's EVA, 113 astronauts and cosmonauts representing nine nations had logged 1,094 hours and 39 minutes of spacewalk time outside the space station, or 45.6 full days. Mastracchio's time outside during his previous six spacewalks totals 38 hours and 30 minutes, putting him 23rd on the list of most experienced spacewalkers.

 

 

© 2013 William Harwood/CBS News

 

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Working weekend? NASA astronauts gear up for Saturday spacewalk on ISS

NASA astronaut Rick Mastracchio checks U.S. spacesuits inside the Quest airlock. He and Mike Hopkins will venture outside the International Space Station on Saturday to start work on replacing a faulty cooling loop pump. (NASA TV / December 20, 2013)

By Amina Khan

December 20, 2013, 4:01 p.m.

A pair of NASA astronauts are gearing up for a trio of spacewalks to fix a cooling loop aboard the International Space Station. The three-part show will take place Saturday, Monday and Wednesday – Christmas Day.

Astronauts Rick Mastracchio and Michael Hopkins are assigned to replace a faulty pump for one of the station's two ammonia cooling loops. The loop has been out of commission since the pump automatically shut down last week after it got too cold for comfort, NASA officials said.

The space station uses ammonia in its external cooling loops, but it's far too toxic to use in the loops inside the station; the internal ones use water instead. But if the ammonia gets too cold, it can freeze the water from the internal system in its pipes. As the water turns into ice, it expands and could crack the pipe, allowing ammonia to enter and poison the system.

Engineers at NASA's Johnson Space Center in Houston identified a problematic valve inside the pump and tried fiddling with the mechanism to see if they could figure out what was wrong and find a way to fix it. Failing that, the NASA team decided to send out Mastracchio, a six-time spacewalk veteran, and Hopkins, a rookie spacewalker who is "very excited to go out the door," said Allison Bolinger, lead U.S. spacewalk officer.

Mastracchio will take the lead for the first two spacewalks, hooking up to the space station's giant robotic arm. The arm will be operated from inside the station by Japanese astronaut Koichi Wakata.

2013: The Year in Science

Even though spacewalks are long – often exceeding six hours – the work will require three of them. It involves a complex set of steps to remove the broken giant pump module – which appears to be roughly the size of a refrigerator — and put in the new one.

For the first spacewalk, the astronauts will focus on pulling out the failed pump module and safely severing the ties between the pump and the larger system, removing four connections called "quick disconnects." They'll also spend a little time working on the spare pump module that will replace the faulty one, removing layers of insulation.

During the second spacewalk, the astronauts will fully remove the failed pump module and temporarily stow it out of the way. Then they'll return to the spare pump, pull it out and fly it back over to the hole where the faulty pump was. On this spacewalk, they plan to hook up only the bolts and the electrical connectors on the spare pump, Bolinger said.

On the Christmas Day spacewalk, Hopkins is expected to take the lead and step into the robotic arm. They'll finish installing the spare pump module, stow the failed pump module in the spot it originally came from, and pack up their tool bag.

It's possible the astronauts may get Christmas off, said Michael Suffredini, International Space Station program manager.

"It could take a little less if we get lucky with the QDs," Suffredini said, referring to the quick disconnects. "And it could take a little more if we're not lucky with the QDs — or we have any other challenges that come up."

The spacewalks would be the first for the United States since Italian astronaut Luca Parmitano nearly drowned in space during the summer. The European Space Agency astronaut's helmet started to fill with water as he floated outside the space station.

Copyright © 2013, Los Angeles Times

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With Makeshift Snorkels, NASA Astronauts Start Spacewalk

By KENNETH CHANG

December 20, 2013

Two NASA astronauts have begun the first of at least two spacewalks aimed at replacing a malfunctioning pump module that is part of the cooling system for the International Space Station.

The astronauts, Col. Michael S. Hopkins of the Air Force and Richard A. Mastracchio, stepped out of an airlock at 7:01 a.m. Eastern time on Saturday for what is scheduled to be six and a half hours of work before they return to the station.

At 8:15 a.m., NASA reported that the astronauts were about 25 minutes ahead of their timeline.

Koichi Wakata, a Japanese astronaut, was operating a robotic arm from inside the station to help with the repairs.

In preparation for the spacewalk, NASA devised makeshift snorkels that would allow an astronaut in a spacesuit to continue breathing even if a sudden water leak should fill the helmet, as happened to an Italian astronaut who almost drowned in July.

Mr. Mastracchio is wearing the same spacesuit — No. 3011 — that leaked in July. During that spacewalk, water partly filled the helmet. The astronaut in the suit then, Luca Parmitano, was able to hurry back to safety, but not before water covered his eyes and blocked his nostrils.

Engineers found that contamination had clogged one of the suit's filters, causing water from the suit's cooling system to back up. Those parts have been replaced, and tests have indicated no lingering problems.

Officials admit to some uneasiness, however, because the source and cause of the contamination remain unknown.

NASA had planned to send a replacement spacesuit to the station. But on Dec. 11, a valve controlling one of two loops of circulating ammonia that cool equipment on the space station malfunctioned. When attempts to control the ammonia flow using a different valve proved inadequate, space station managers decided to send the astronauts out on the spacewalks.

Engineers have devised low-tech countermeasures in case water again floods into a helmet.

An absorbent pad installed in the back of the helmet can hold 20 to 27 ounces, or about 600 to 800 grams, of water. The astronauts will periodically tilt their heads back to check if the pads have become "squishy."

In the first check about half an hour into the spacewalk, Colonel Hopkins and Mr. Mastracchio reported no signs of moisture.

Crew members made the improvised snorkels out of available materials: plastic tubing and Velcro. The tubes extend from the helmet down into the chest area of the spacesuit. If water is encroaching on the astronaut's face, "this is your last resort," said Allison Bolinger, the lead spacewalk officer. "The crew member can lean down and use this to breathe, to receive fresh oxygen down near his midsection."

Colonel Hopkins and Mr. Mastracchio will disconnect cables to the pump module and open up the insulation that covers it.

The ammonia pump itself is operating normally, but the ammonia has been too cold because of the problem with the valve, which controls the temperature. That led to the shutdown of an internal cooling loop of circulating water, to stop the cold ammonia from freezing the water. There is no immediate danger to the station's six crew members, but the station would be in more serious trouble if the other ammonia loop malfunctioned.

On the second spacewalk, planned for Monday, the astronauts are to replace the 780-pound pump module with a spare one. If necessary, a third spacewalk would take place on Wednesday.

&lt;img src="http://meter-svc.nytimes.com/meter.gif"&gt;

A version of this article appears in print on December 21, 2013, on page A12 of the New York edition with the headline: With Makeshift Snorkels, NASA Astronauts Start Spacewalk.

© 2013 The New York Times Company 

 

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Snorkel-clad spacewalkers leave station to begin crucial repair

By Irene Klotz

CAPE CANAVERAL, Florida (Reuters) - Two NASA astronauts, their spacesuits newly modified with snorkels in case of another water leak, floated outside the International Space Station on Saturday to begin a marathon three-day task to fix the outpost's cooling system.

The spacewalk, which is being broadcast live on NASA Television, is the first for NASA since July when the spacesuit helmet worn by Italian astronaut Luca Parmitano began filling with water, a situation that could have caused him to drown.

Saturday's spacewalk was prompted by the December 11 shutdown of one of the station's two ammonia cooling systems, which forced the crew to turn off non-essential equipment and shut down dozens of science experiments.

While the six-member crew is not in danger, the remaining cooling system cannot support the three laboratories and other modules on the U.S. side of the $100 billion station, a project of 15 nations. The Russian side of the station has a separate cooling system.

Engineers at the Johnson Space Center in Houston tried devising ways to bypass a suspected faulty pump valve, but with time running short, managers decided to have astronauts replace the pump, located outside the station, with a spare.

The work is expected to take station flight engineers Rick Mastracchio and Mike Hopkins three spacewalks to complete, the first of which began at 7:01 a.m. EST/1201 GMT on Saturday as the station sailed 260 miles over the southern Atlantic Ocean.

"Beautiful day. Awesome view," Mastracchio, a veteran of six spacewalks, said as opened the airlock's hatch to begin the planned 6.5-hour outing.

He and Hopkins wore spacesuits that were modified to protect them from another possible water leak. The problem in July was traced to contamination in piece of equipment called a fan pump separator, which circulates water and air in the spacesuit and removes moisture from air.

How the water-separator portion of the device became clogged remains under investigation, but NASA managers say they are confident the problem will not reoccur during Saturday's spacewalk.

Hopkins, who is making his first spacewalk, is wearing Parmitano's spacesuit, but it has been outfitted with a new fan pump separator.

In addition, both Hopkins and Mastracchio rigged their helmets with homemade snorkels, fabricated out of pieces of plastic tubing and Velcro, which they can use for breathing in case of another water leak.

The helmets also now include water-absorbent pads that can hold up to 27 ounces (800 milliliters) of water, said NASA's lead spacewalk officer Allison Bolinger.

The pads are attached to the back of the astronauts' helmets. During the spacewalk, Mastracchio and Hopkins periodically will test if the pads are squishy by leaning their heads back.

"This is our first line of defense," Bolinger told reporters during a press conference on Wednesday.

"As soon as the crewmember senses squishiness ... that's the sign that there is a problem in the (spacesuit) and it's time to come inside," she said.

RISKY WORK

During Saturday's spacewalk, Mastracchio and Hopkins are expected to prepare the 780-pound (354 kg), 5-foot (1.5 meter) wide cooling system pump for removal. A spare will be installed during two more spacewalks, scheduled for Monday and Wednesday.

The failed pump, which is located on a pallet on the right side of the station's external truss, will be stored outside the station for possible future repair and reuse.

It was installed in 2010 during an unexpectedly difficult series of spacewalks by astronauts Doug Wheelock and Tracy Caldwell Dyson.

"What makes this pump very difficult (to work on) are (the) fluid disconnects because they are so large and they are pressurized and they contain liquid ammonia, so that's a hazard for us if it were to come in contact with us or our suits," Caldwell Tyson said in an interview with a NASA TV mission commentator.

Maintaining focus also can be a challenge, she added. "When you're on one of those pallets, you really have that sensation that you are sticking out on the edge of a skyscraper. Especially when you look down, you see your feet and then you see the Earth going 17,500 mph beneath you, it really does get your attention," Caldwell Dyson said.

"You tend to slow down and be a lot more careful when you have a backdrop like that," she said.

(Reporting by Irene Klotz; Editing by Vicki Allen)

 

Copyright © 2013 Reuters Limited. All rights reserved. 

 

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NASA astronauts begin urgent spacewalking repairs

By MARCIA DUNN 

 

CAPE CANAVERAL, Fla. (AP) — Astronauts ventured out Saturday on the first of a series of urgent repair spacewalks to revive a crippled cooling line at the International Space Station.

The two Americans on the crew, Rick Mastracchio and Michael Hopkins, will need to perform two and, quite possibly, three spacewalks to replace an ammonia pump containing a bad valve.

Next will be one Monday, followed by a third on Christmas Day if it's needed.

The breakdown 10 days ago left one of two identical cooling loops too cold and forced the astronauts to turn off all nonessential equipment inside the orbiting lab, bringing scientific research to a near-halt and leaving the station in a vulnerable state.

Mastracchio got off to a quick start on the repairs as he worked to disconnect the flawed pump.

"Looking good so far," he told Mission Control as he unhooked four ammonia fluid lines. He encountered a loose bolt and informed Mission Control he was afraid it might come off, but was assured everything was fine. A few minutes later, he reported that some flakes of frozen ammonia — a toxic substance — brushed against his suit. "More flakes coming out," he radioed. "A steady stream of them."

Mastracchio, a seven-time spacewalker, and Hopkins, making his first, wore extra safety gear as they floated outside. NASA wanted to prevent a recurrence of the helmet flooding that nearly drowned an astronaut last summer, so Saturday's spacewalkers had snorkels in their suits and water-absorbant pads in their helmets.

Two hours into the spacewalk, the spacewalkers were still dry.

The pump replacement is a huge undertaking attempted only once before, back in 2010 on this very unit. The two astronauts who tackled the job three years ago were in Mission Control, offering guidance, as Saturday's drama unfolded 260 miles up. Mastracchio promised to bring back a wire tie installed on the pump by the previous spacewalkers. "Oh, awesome, thanks Rick," replied the astronaut in Mission Control who put it on.

The 780-pound pump is about the size of a double-door refrigerator and extremely cumbersome to handle, with plumbing full of dangerous ammonia. Any traces of ammonia on the spacesuits must be dissipated by the time the astronauts go back inside, to avoid further contamination.

NASA's plan — fine-tuned over the past several days — called for the pump to be disconnected Saturday, pulled out Monday and a fresh spare put in, and then all the hookups of the new pump completed Wednesday. If the work is finished on the first two spacewalks, the third wouldn't be needed.

It would be the first Christmas spacewalk ever for NASA.

In the days following the Dec. 11 breakdown, flight controllers attempted in vain to fix the bad valve through remote commanding. Then they tried using a different valve to regulate the temperature of the overly cold loop, with some success. But last Tuesday, NASA decided the situation was severe enough to press ahead with the spacewalks. Although the astronauts were safe and comfortable, NASA did not want to risk another failure and a potential loss of the entire cooling system, needed to radiate the heat generated by on-board equipment.

NASA delayed a delivery mission from Wallops Island, Va., to accommodate the spacewalks. That flight by Orbital Sciences Corp., which should have occurred this past week, is now targeted for Jan. 7.

Until Saturday, U.S. spacewalks had been on hold since July, when an Italian astronaut's helmet was flooded with water from the cooling system of his suit. Luca Parmitano barely got back inside alive.

Engineers traced the problem to a device in the suit that turned out to be contaminated — how and why, no one yet knows.

For Saturday's spacewalk, Hopkins wore Parmitano's suit, albeit with newly installed and thoroughly tested components.

Just in case, NASA had Mastracchio and Hopkins build snorkels out of plastic tubing from their suits, before going out. The snorkels will be used in case water starts building up in their helmets. They also put absorbent pads in their helmets; the pads were launched from Earth following the July scare.

 

Copyright © 2013 The Associated Press. All rights reserved. 

 

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NASA Astronauts Step Outside Space Station for 1st of 3 Holiday Spacewalks

by Miriam Kramer, Staff Writer   |   December 21, 2013 07:14am ET

Astronauts Mike Hopkins and Rick Mastracchio ventured outside of the International Space Station to begin repairs on the station's vital cooling system on Dec. 21. Credit: NASA TV View full size image

Two NASA astronauts have begun the first of three quickly planned spacewalks to fix a problem with the International Space Station's vital cooling system.

NASA astronauts Mike Hopkins and Rick Mastracchio ventured outside of the space station's Quest airlock today (Dec. 21) to begin the repairs. The spacewalk officially began at 7:01 a.m. EST (1200 GMT) when the two astronauts took their spacesuits to internal power. NASA TV will broadcast the entire 6.5-hour EVA (extra-vehicular activity or spacewalk), and you can watch the spacewalk live on SPACE.com.

"It's a beautiful day," one of the astronauts said as he stepped outside of the orbiting outpost.

Mastracchio and Hopkins are leaving the confines of the station to remove and replace a failed pump module that helps keep equipment inside and outside of the space laboratory cool. The six space station residents are not in any immediate danger, but in order to get the station up to its fully functional status, the two astronauts will need to perform the spacewalks scheduled for today, Dec. 23 and, if necessary, Christmas Day (Dec. 25), NASA officials said. [Photos: Astronauts Spacewalk Outside to Fix Vital Cooling System]

 

For this first spacewalk, Hopkins and Mastracchio will focus on preparing the failed pump module for removal and getting the replacement module — stored outside of the station — ready for installation. Mastracchio will be connected to the space station's robotic arm during much of the spacewalk, and he is wearing the suit with red stripes. Hopkins' spacesuit has no stripes.

"We refer to it as a contingency spacewalk, and the skills really are fundamental," NASA astronaut Doug Wheelock said of the spacewalks during a NASA TV event Thursday. "We practice all of these skills, just rehearse them over and over again in the pool. The crew has done these particular skills. The skills are the same, but space always has surprises for us, especially when we go outside."

Veteran spacewalker Mastracchio has performed six EVAs totaling 38 hours and 30 minutes of spacewalk time. Today's spacewalk is Hopkins' first EVA. Japanese astronaut Kiochi Wakata will assist them from inside the station, driving the robotic arm.

Three Russian cosmonauts also live and work aboard the space station with Mastracchio, Hopkins and Wakata. Oleg Kotov, Sergey Ryazanskiy and Mikhail Tyurin round out the orbiting outpost's Expedition 38 crew.

Spaceflight firm Orbital Sciences was scheduled to launch an unmanned Cygnus spacecraft on a resupply mission to the space station on Dec. 19, however, that launch was pushed to no earlier than Jan. 7 to accommodate the urgent spacewalks.

 

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