Third STS-131 Spacewalk Completed

Image comment: STS-131 astronauts are seen here as they were trying to affix an old ammonia tank to the payload bay of space shuttle Discovery

Image credits: NASA TV

Earlier today, two STS-131 mission specialists stepped out of the International Space Station's (ISS) Quest airlock, to conduct the third and final spacewalk in their schedule. NASA astronauts Rick Mastracchio and Clayton Anderson each performed the sixth extra-vehicular activity (EVA) of their careers, and they managed to successfully complete all the major chores allotted to them. They successfully replaced a large, old ammonia tank on the outer hull of the ISS with a new one and then deposited the old one back into the payload bay of space shuttle Discovery.

Their sortie began at 2:14 am (0614 GMT) and was originally programmed to last for about six and a half hours. However, the two hit an obstacle in their efforts when Mission Control announced them that one of the valves on the four hoses they had just installed appeared to be stuck. The hoses transport liquid ammonia coolant to the tank and are essential for maintaining proper temperature levels on the ISS. As experts on the ground struggled to fix the glitch on their end, Mastracchio and Anderson had their own problems with installing the old ammonia tank in the orbiter's payload.

A stubborn bolt gave them some trouble, which was nothing new. In the previous two STS-131 EVA, the astronauts encountered other instances in which bolts would not budge. They needed to use prybars and even brute force at times to get them loose. This instance was different in the sense that the small metal piece was misaligned. Therefore, the two astronauts needed to unscrew another bolt, align the entire plate properly, and then affix them all back into place. After they completed this chore, they removed some unneeded aluminum coverings from the outer hull of the orbital facility. This task was originally planned for their second EVA, but delays made them leave this job for today.

“We have two roll-over tasks that were originally planned as part of [the second spacewalk] that are going to be added to the front end. After they do that, they'll go on and essentially proceed with the remainder of [the third spacewalk], in large part what was planned pre-flight,” explained Mike Sarafin, the Lead Shuttle Flight Director at NASA. As the astronauts were working outside, their colleagues inside the ISS continued the task of unloading some of the 17,000 pounds (7,711 kilograms) of supplies from the newly-arrived MPLM (Multi-Purpose Logistics Module) Leonardo. Completely unloading the container will take a few more days, NASA officials announce, quoted by Space.

Discovery astronauts complete second spacewalk

In this image provided by NASA-TV astronauts Rick Mastracchio, left, and Clay Anderson work on the International Space Station early Sunday morning April 11, 2010. Mastracchio and Anderson earlier had trouble bolting down the new ammonia tank assebly on the sprawling framework that serves as the backbone of the space station. The 215-mile-high action unfolded on the 40th anniversary of the launch of Apollo 13. (AP Photo/NASA)

Expedition 23 crew members share a meal at the galley in the Zvezda Service Module of the International Space Station. Pictured from the left are Russian cosmonauts Oleg Kotov, commander; Mikhail Kornienko, flight engineer, and Alexander Skvortsov, Soyuz commander and flight engineer. Image Credit: NASA

Two astronauts from the US shuttle Discovery completed Sunday a second spacewalk as part of efforts to replace a depleted ammonia coolant tank outside the International Space Station.

Mission specialists Rick Mastracchio and Clay Anderson finished their seven-hour, 26-minute walk in open space at 8:56 am EDT (1256 GMT), after installing a new ammonia tank on a space station truss, NASA officials said.

Due to a "troublesome bolt," NASA said the walkers ran out of time and were unable to complete all their scheduled work, including retrieving two micrometeoroid debris shields that were to return to Earth.

The spacewalk -- on the 40th anniversary of the launch of Apollo 13, the famously aborted 1970 mission to the moon -- was the second of the three scheduled walks for this mission, and was the 142nd in service of the orbiting outpost's construction.

During the first spacewalk on Friday, Anderson and Mastracchio retrieved an experiment from the Japanese Kibo Laboratory on the station's porch and replaced a Rate Gyro Assembly, part of the station's navigation system.

The final spacewalk of the mission is scheduled for Tuesday.

The Discovery, which blasted off from Kennedy Space Center at Cape Canaveral, Florida on Monday, docked on Thursday with the International Space Station.

Eight tonnes of supplies, gear and racks of science experiments were transferred from the shuttle to the space station in an Italian-made module known as Leonardo.

Besides the replacement ammonia tank, the gear included a freezer to preserve samples of blood, urine, saliva, plants or microbes used in micro-gravity experiments for later analysis back on Earth.

Meanwhile, the US National Aeronautics and Space Administration announced Saturday that Discovery's mission had been extended by an extra 24 hours for routine heat shield inspections.

Landing was now scheduled for Monday, April 19, at 1254 GMT (8:54 am local time) to cap what will be a 14-day mission.

"Since Discovery's Ku-Band communications system is not functioning correctly, the space station's Ku system will transmit the heat shield video and laser scan to Mission Control for imagery experts to analyze," NASA said in a statement.

Discovery's Ku-Band system has been down since the shuttle reached orbit April 5.

Normally the shield inspection is done before reentry but after undocking from the ISS. It is aimed at making sure heat shields have not been damaged by space debris or small meteorites.

The shuttle's heat shield is subjected to temperatures as high as 1,500 degrees Celsius (2,732 Fahrenheit) due to friction on reentry.

First Discovery Spacewalk Ends in Success

Image comment: Spacewalker Rick Mastracchi, an STS-131 mission specialist, is seen exiting the Quest airlock on the ISS, before beginning the first EVA of the mission

Image credits: NASA TV

After more than 6 and a half hours of working outside of the International Space Station (ISS), two NASA astronauts managed to successfully complete the chores they were entrusted with. Now, back inside the orbital facility, shuttle mission specialists Rick Mastracchio and Clayton Anderson boast having moved a new, massive ammonia tank from Discovery's payload bay to a new location on the international lab. The tank will remain there provisionally, as the old one is removed, Space reports.

The extra-vehicular activity (EVA) was not without issues, NASA Mission Control experts say. At one point, the bulky tank got stuck inside the payload bay, and the two astronauts had to use a pry bar to get it to move. After this obstacle was cleared, everything went on smoothly, and that cargo was secured to its provisional docking site. During the next two EVA planned as part of the STS-131 mission, the same two spacewalkers will remove one of the old ammonia tanks from the station, and will place it in the orbiter's bay. Afterwards, the new piece of equipment will be secured at its permanent location.

These tanks are of vital importance for the ISS' thermal control system. They are very large containers, weighing about 1,700 pounds, or 771 kilograms, and are filled with the toxic chemical. In the particular conditions on the orbital facility, the substance acts as a coolant, helping maintain a constant temperature aboard. Once the old, depleted tank is returned to NASA, engineers at the agency will start refurbishing the component, and will then fill it back again, in case it is needed back on the station. Also during the first EVA, the two astronauts removed a Japanese science experiment from the outer hull of the ISS, and replaced a damaged sensor.

“Outside the station, the first spacewalk is going on. Inside the station, we moved four racks from MPLM [the Multi Purpose Logistics Module Leonardo] to ISS. Big moving day!” twittered JAXA astronaut Soichi Noguchi, who is a member of the Expedition 23 crew aboard the outpost. After today's work, the 13 astronauts currently in orbit will rest for a bit, ahead of Sunday's second planned EVA, also featuring Mastracchio and Anderson. The two have just performed their fourth spacewalk. Once the current mission is over, they will have performed six each.

Astronauts take 1st spacewalk of shuttle mission

In this image made from video and released by NASA, astronauts Rick Mastracchio, center, is seen preparing the external stowage platform on the International Space Station for the new ammonia tank during the first spacewalk on the International Space Station, Friday April 9, 2010. It will take three spacewalks to complete the job. (AP Photo/NASA)

Two astronauts from the shuttle Discovery began a six-and-a-half-hour spacewalk Friday, working on an ammonia tank on the outside of the International Space Station, NASA said.

Mission specialists Clayton Anderson and Rick Mastracchio left the shuttle's airlock at 0531 GMT for the first of three space walks during the 13-day mission to resupply the space station.

Mastracchio, the lead spacewalker, was seen in images beamed to Earth working on an ammonia tank on the outside of the space station, which will be replaced with a new tank. The ammonia is used in the space station's cooling system.

They will also retrieve a science experiment from a Japanese laboratory facility on the station's porch.

The Discovery, which blasted off from Kennedy Space Center at Cape Canaveral, Florida on Monday, docked on Thursday with the International Space Station.

Eight tons of supplies, gear and racks of science experiments were transferred from the shuttle to the space station in an Italian-made module known as Leonardo.

Besides the replacement ammonia tank, the gear included a freezer to preserve samples of blood, urine, saliva, plants or microbes used in micro-gravity experiments for later analysis back on Earth.

earlier related report
Discovery unloads supplies for space station
Washington (AFP) April 7, 2010 - The Discovery crew began to deliver supplies to the International Space Station on Thursday and prepared for the mission's first spacewalk a day after the US space shuttle docked with the orbiting station.

Discovery astronauts opened the hatch to unload the Italian-made Leonardo Multi Purpose Logistics Module to start the transfer some eight tonnes of science racks and other supplies into the space station, a job that will take several days, NASA said.

Discovery's Clayton Anderson and Soichi Noguchi opened the hatch to the "moving van" at around 1200 GMT.

American Stephanie Wilson and Japanese Naoko Yamazaki operated the ISS robot arm to extract the Leonardo and attach it to the Harmony node around 0430 GMT.

Discovery had carried the scientific equipment along with extra sleeping quarters to the ISS.

Other gear hauled into space included a freezer to preserve samples of blood, urine, saliva, plants or microbes used in micro-gravity experiments for later analysis back on Earth.

Discovery is also carrying an exercise machine designed to study the effects of weightlessness on the body's musculoskeletal system. Muscles can atrophy during long sojourns in space so astronauts have to exercise regularly.

The astronauts bunked down later and prepared for the mission's first spacewalk at 0541 GMT Friday.

The Discovery crew was welcomed with hugs and handshakes Wednesday aboard the International Space Station after a successful docking high over the Caribbean.

It marked the first time ever that four women were in orbit together, as well as the first time two Japanese astronauts were in space at the same time.

Discovery blasted off Monday from Kennedy Space Center at Cape Canaveral, Florida in a launch marred only by the failure of an antenna used to transmit television pictures back to Earth that also is part of its radar docking system.

The 13-day mission is one of the last before the US shuttle fleet is retired at the end of this year after 30 years of service.

The International Space Station, a 100-billion-dollar project begun in 1998 with the participation of 16 countries, is financed mainly by the United States.

Once the shuttle program ends, the United States will depend on Russian Soyuz spacecraft to ferry their astronauts to the station until a new US launch vehicle is ready to take over around 2015.

Shuttle Crew Completes First STS-130 Spacewalk

STS-130 crew members installed a 2,600-cubic-foot addition to the International Space Station early Friday, combining the talents of robotic arm operators and spacewalkers to connect the Italian-built Tranquility module.

Tranquility was installed at 1:20 a.m. EST Friday over the Indian Ocean west of Singapore. Mission Specialist Kay Hire and Pilot Terry Virts used the station's Canadarm2 to pull Tranquility out of space shuttle Endeavour's payload bay and position it on the port side of the station's 10-year-old Unity module. Tranquility was locked in place with 16 remotely controlled bolts.

Spacewalkers Bob Behnken and Nick Patrick stepped outside the Quest airlock module at 9:17 p.m. Thursday and immediately began preparing the new module for its trip from the cargo bay to the station. Mission Specialist Steve Robinson helped coordinate the 6-hour, 32-minute spacewalk, which ended at 3:49 a.m. Friday. As Behnken and Patrick waited for the robotic arm operators to carefully maneuver Tranquility into position, they relocated a temporary platform from the Special Purpose Dexterous Manipulator, or Dextre, to the station's truss structure and installed two handles on the robot.

Once Tranquility was structurally mated to Unity, the spacewalkers connected heater and data cables that will integrate the new module with the rest of the station's systems. They also pre-positioned insulation blankets and ammonia hoses that will be used to connect Tranquility to the station's cooling radiators during the mission's second spacewalk that begins Saturday night. The station's new room with a view, the cupola, will be moved from Tranquility's end to its Earth-facing port on Sunday.

As the spacewalk ended, Mission Control reported that all data and heater connections were working well, and that the vestibule separating Tranquility and Unity had passed its initial leak check.

Two Spacewalks Complete, Station Crew Prepares for Visitors

Expedition 20 Commander Gennady Padalka and Flight Engineer Michael Barratt have completed two Russian spacewalks. The first spacewalk took place on June 5 outside the Zvezda service module. The second took place on June 10 inside Zvezda. Both excursions were dedicated to readying the space station for the arrival of the Russian Mini-Research Module 2 in November.

The crew is recharging the Russian Orlan spacesuits and debriefed spacewalk specialists in Russia. In addition, the crew will dry the suits, take radiation measurements and prepare them for stowage.

Image above: The six-member Expedition 20 crew shares a meal inside the Unity node. Credit: NASA

The six station residents will welcome the STS-127 crew when it arrives Monday, June 15, aboard space shuttle Endeavour. Mission Specialist Tim Kopra will trade places with Expedition 20 Flight Engineer Koichi Wakata. Kopra will remain with Expedition 20 while Wakata will return to Earth with STS-127 on Sunday, June 28.

Station Crew Completes Spacewalk, Ready for STS-127

The six members of the Expedition 20 crew aboard the International Space Station focused their attention Wednesday on post-spacewalk activities and preparations for the arrival of space shuttle Endeavour and the STS-127 crew.

Commander Gennady Padalka and Flight Engineer Michael Barratt completed an internal spacewalk Wednesday at 3:07 a.m. EDT.

Image above: Expedition 20 Flight Engineer Robert Thirsk works in the Columbus laboratory of the International Space Station. Credit: NASA

Padalka and Barratt replaced a cover on Zvezda’s zenith docking port with a docking cone. The excursion took place internally with the spacewalkers attached to umbilicals in Zvezda for life support. It lasted about 12 minutes.

The excursion was the shortest of the 125 spacewalks in support of station assembly and maintenance. It was conducted eight years and two days after Jim Voss and Yury Usachev of Expedition Two conducted a similar internal spacewalk in 2001 to position the same docking cone to the nadir port of the Zvezda transfer compartment in advance of the arrival of the Pirs Docking Compartment.

Docking antennas, a docking target and electrical connectors were installed on the exterior of the Zvezda service module when Padalka and Barratt completed their first Expedition 20 spacewalk Friday.

The station is now ready for the docking of the Mini-Research Module 2, or MRM2, later this year. The MRM2 will dock automatically to the zenith port of Zvezda and will serve as an additional docking port for Russian vehicles.

After reconfiguring the station for normal operations, the crew began an extended sleep period around 8:20 a.m. A wake up time of 2 a.m. Thursday will set in motion preparations for the arrival of the STS-127 crew early next week for 11 days of joint docked operations.

Endeavour and the STS-127 crew are scheduled to launch to the station Saturday, June 13, bringing with them the Kibo Japanese Experiment Module Exposed Facility and Experiment Logistics Module Exposed Section. They will also bring astronaut Timothy Kopra, who will take Flight Engineer Koichi Wakata’s place aboard the orbital outpost.