Atlantis Unveiled for Historic Final Flight amidst Stormy Weather

Atlantis awaits blastoff on STS-135 Mission. Credit: Ken Kremer

The last Space Shuttle in history that will blast off for space was unveiled today at the Kennedy Space Center (KSC) in Florida amidst terrible weather. Heavy rain showers and thunderstorms are inundating the space center during prelaunch preparations for the blast off of Space Shuttle Atlantis.

Two lightning strikes occurred within about a third of a mile of Launch Pad 39 at 12:31 p.m. and 12:40 p.m. EDT. After engineering teams evaluated data from the strikes, NASA shuttle managers decided it was safe to proceed with launch preparations.

Following about a 40 minute delay, Atlantis was unveiled for liftoff after retraction of the massive rotating service structure which protects the orbiter from inclement weather and impacts from foreign object debris.

IMG_9164a_STS 135_Ken Kremer

The chances of favorable weather for launch of the STS-135 mission on Friday July 8 are just 30%, meaning 70% NO GO said Shuttle Weather officer Kathy Winters at a briefing for reporters today at KSC. Liftoff is targeted for 11:26 a.m. EDT.

NASA has a narrow window of three opportunities on July 8, 9 and 10 and must then stand down for nearly a week because the US Air Force has scheduled a Delta rocket launch on July 14. If the Air Force would agree to delay the Delta by few days, NASA could launch Atlantis on Monday or Tuesday in case for further launch delays.

Upwards of 750,000 spectators are expected.

Atlantis goal is deliver the Raffaello logistics module and the Robotic Refueling Mission to the ISS on a 12 day mission that will end the shuttle era.

Atlantis poised on for the final time on Launch Pad 39A at the Kennedy Space Center. Credit: Ken Kremer
Closeup of the White Room leading to the crew cabin. Credit: Ken Kremer

Video of Lightning Strike near Shuttle Launch Pad

Counting down to the Last Shuttle; Stormy weather projected

Space Shuttle Atlantis awaits Blastoff on July 8, 2011 from Launch Pad 39A at the Kennedy Space Center in Florida. Credit: Ken Kremer


The countdown to NASA’s 135th and final shuttle launch began today (July 5) with no technical issues blocking liftoff at this time. But upwards of 750,000 spectators may be disappointed because the weather on launch day, July 8, is looking decidedly dicey. Storm weather and stormy seas lie ahead for NASA.

At today’s press briefing, Shuttle Weather Officer Kathy Winters projected that the chance of favorable weather is only 40% for Friday’s 11.26 a.m. liftoff of Atlantis because of the likely threat of rain at the Kennedy Space Center.

The 12 day STS-135 mission will loft about 9500 pounds of supplies and equipment that NASA shuttle managers state are absolutely “mandatory” in order to keep the International Space Station operating at full capacity for the next year.

“I wish I had a better weather briefing for you, but it does look like we are going to have some weather, at least potential for weather, in the area at launch time,” said Winters. “Right now, we’re going with a 60 percent chance of KSC weather prohibiting launch due to the potential for showers and isolated thunderstorms in the area.”

In the event of a one day delay to Saturday, the chances for favorable weather increases considerably to 60%. For a two day delay to July 10, the chances of acceptable weather climbs to 70%.

After July 10, the liftoff of the STS-135 mission would have to be delayed to July 16 because NASA would be forced to stand down shuttle launch operations in order to allow the Air Force to launch a military navigation satellite on July 14 from Cape Canaveral. That is unless the Air Force relents – out of consideration for the three quarters of a million folks expected to jam the Florida space coast beaches, highways and hotels – and offers NASA the opportunity to launch Atlantis for several days starting on July 11 – in case of a launch delay.

STS-135 crew at base of Launch Pad 39A, Kennedy Space Center. From left; Mission Specialists Rex Walheim and Sandy Magnus; Pilot Doug Hurley and Commander Chris Ferguson. Credit: Ken Kremer

Space fans need to be patient and plan for undesired contingencies just like NASA by packing extra provisions like food, water and clothing and also should consider extended accommodations.

Clocks began ticking backwards today at 1p.m.EDT at the T Minus 43 hour mark towards the final blastoff of Space Shuttle Atlantis.

NASA Test Director Jeremy Graeber said at today’s briefing that Atlantis is ready to fly.

“Our teams here at the Kennedy Space Center and all the NASA centers across the country have been working for over a year to prepare Atlantis, the external tank our solid rocket boosters, the payload and all of our ground systems for the STS-135 mission,” Graeber stated. “All of our vehicle and ground systems are ready, the STS-135 crew, Atlantis and the launch team are all ready to proceed and we’re looking forward to a spectacular launch on Friday morning.”

STS-135 payload manager Joe Delai said the payloads and the Raffaello cargo carrier module are ready to go as well. “The primary objective of Atlantis is to resupply the ISS for one year. About 9500 pounds are going up. This is the largest payload in terms of volume.”

Delai said that Raffaello was specially modified to increase its cargo carrying capacity by several hundred pounds.

The STS-135 mission will bring NASA’s 30 year long shuttle program to a definite close and simultaneously mark the termination of the US capability to launch humans to space for at least several years.

Space Shuttle Atlantis perched on top of Pad 39A for the Grand Finale of the shuttle program.
Credit: Ken Kremer
NASA KSC shuttle managers brief media about the payload and launch status of the STS-135 mission to the International Space Station. From left: NASA Test Director Jeremy Graeber, Payload Mission Manager Joe Delai and Shuttle Weather Officer Kathy Winters

Atlantis Crew Jets to Florida on Independence Day for Final Shuttle Blastoff

The final Shuttle Crew jets into the Kennedy Space Center on Independence Day, 2011. From Left: Shuttle Commander Chris Ferguson, Pilot Doug Hurley and Mission Specialists Sandy Magnus and Rex Walheim. Credit: Ken Kremer


The four astronauts who will fly the Grand Finale of NASA’s space shuttle program arrived at the Florida launch site on Independence Day on a wave of T-38 training jets. The veteran crew flew into the Kennedy Space Center (KSC) from Ellington Field in Houston, Texas and touched down at the shuttle landing strip at about 2:30 p.m. EDT.

Blast off of Space Shuttle Atlantis on the STS-135 mission is slated for July 8 at 11.26 a.m. with Shuttle Commander Chris Ferguson at the helm. He is joined by Pilot Doug Hurley and Mission Specialists Sandy Magnus and Rex Walheim.

Upon landing in the sweltering Florida heat, the astronauts were welcomed by Space Shuttle Launch Director Mike Leinbach as well as other NASA/KSC officials and a large crowd of media. Many waved US flags in honor of the July 4th Independence Day holiday.

Shuttle Commander Chris Ferguson addresses the media about the STS-135 mission. Credit: Ken Kremer

“I think I speak for the whole crew in that we are delighted to be here after a very arduous nine month training flow and we’re thrilled to finally be here in Florida for launch week,” said Ferguson. “This is a day that’s decidedly American, a day where we kind of reflect on our independence and all the wonderful things that we really have as part of being the United States of America. I think it’s wonderful you’ve all come out to join us.”

“We have a very event-filled mission ahead of us, we have 12 days, we’ll be very, very busy,” Ferguson added. “When it’s all over, we’ll be very proud to put the right-hand bookend on the space shuttle program.”

The quartet will spend the next few days completing final prelaunch training to prepare for their planned 12 day flight bound for the International Space Station.

The primary cargo is the Raffaello Multipurpose Logistics module built in Italy and jam packed with some five tons of spare parts, science gear, food, water, clothing and more that will be transferred to the station by the station and shuttle crews and are absolutely essential to keep the orbiting outpost operating over the next year.

About 2000 journalists and photographers are expected to cover Atlantis’s launch, the largest media gathering for a shuttle launch since the Return to Flight in 2005 – that’s about twice the media here for the last launch of Endeavour in April.

The countdown clock begins ticking at 1 p.m. EDT on Tuesday, July 5

Shuttle Launch Director Mike Leinbach greets Commander Ferguson. Credit: Ken Kremer
Doug Hurley and Sandy Magnus speak to reporters at the shuttle landing strip. Credit: Ken Kremer
STS-135 crew jets to Florida on T-38 training jets for planned July 8 blastoff. Shuttle Commander Chris Ferguson flew this jet accompanied by Sandy Magnus. Credit: Ken Kremer
STS 135 crew arrives in Florida at the Shuttle Landing Facility. Credit: Ken Kremer

Read my prior features about the Final Shuttle mission, STS-135, here:
NASA Sets July 8 for Mandatory Space Shuttle Grand Finale
Final Shuttle Voyagers Conduct Countdown Practice at Florida Launch Pad
Final Payload for Final Shuttle Flight Delivered to the Launch Pad
Last Ever Shuttle Journeys out to the Launch Pad; Photo Gallery
Atlantis Goes Vertical for the Last Time
Atlantis Rolls to Vehicle Assembly Building with Final Space Shuttle Crew for July 8 Blastoff

Why Can We See Multiple ISS Passes Right Now?

Four ISS passes over the UK last night. Credit: Mark Humpage

Last night in the UK, US and Europe, we were spoiled with multiple and bright ISS passes. Not just one or two, but up to six passes were able to be viewed throughout the evening in some locations.

This is quite rare as normally we get only one or maybe two visible passes in the evening or morning.

So why are we getting as many as four to six passes per night?

The ISS did receive an orbital boost and its altitude increased by around 20 kilometers. The orbital height of the ISS has an effect on how many visible passes there are at present in the Northern hemisphere. Another reason is because of the time of year.

We are only a week or so away from the Summer Solstice, the time of year when the Northern hemisphere receives the most hours of sunlight. Naturally this means we only have a few hours of darkness and the further North you go, the shorter the nights are and in some locations this time of year, it doesn’t ever get truly dark.

So why does this affect the ISS?

Basically the ISS visible passes have increased due to the station being illuminated much more by the Sun as there are more hours of sunlight right now, but the effect will wear off when we pass through Summer solstice and the nights get longer again.

Take advantage of this rare time and go outside and enjoy the ISS as much as you can in this series of visible passes.

Need to know how and when you can see the ISS? NASA has a Skywatch page where you can find your specific city to look for satellite sighting info., has a Satellite Tracker Tool. Just put in your zip code (good for the US and Canada) to find out what satellites will be flying over your house.

Heaven’s Above also has a city search, but also you can input your exact latitude and longitude for exact sighting information, helpful if you live out in the country.

Credit: Mark Humpage

Ron Garan’s Videoblog from Space

What is it really like to live in space? ISS astronaut Ron Garan has been steadily communicating his experiences on board the space station since he arrived in April, with his Fragile Oasis blog, his Twitter feed and Twitpic account. Now he’s started a videoblog, to visually and verbally share even more of what it is like to live on the ISS for a long duration mission. His accompanying blog post also includes a transcript and some of the images he talks about.

STS-122: A Mission in Pictures

Welcome home to the crew of STS-122! Space shuttle Atlantis landed at 9:08 am EST on February 20, following the STS-122 mission to install the European Space Agency’s Columbus science module on the International Space Station. After such a successful mission, its now time to sit back and enjoy some of our favorite images from Atlantis’ journey to the ISS.

Atlantis launches. Image credit: NASA

Atlantis launches on February 7, 2008. Weather forecasts predicted unfavorable launch conditions, but it turned out to be a beautiful day for liftoff.

External Tank. Image: NASA

A unique picture of the external fuel tank after separation from the shuttle. Residual crygenics vent from the tank, highlighted by sunlight against the backdrop of space.

Shuttle nose.  Image:  NASA

Here’s a view you don’t see everyday: a closeup of the shuttle’s nose at station approach as the shuttle performs a flip maneuver that allows the station crew to take hi-resolution photos of the shuttle’s thermal protection system.

Columbus module.. Image: NASA

The ISS’s Canadarm 2 moves the new Columbus science module out of Atlantis’ payload bay to its home on the station, on the starboard side of the Harmony module. This picture was taken through a window of the ISS.

Stanley Love spacewalk.  Image:  NASA

Astronaut Stanley Love frames a scene with his hands during the first EVA of the mission. It was a bonus spacewalk for Love. Love filled in for Hans Schlegel, who was ill and unable to participate in the EVA. The spacewalk went off without a hitch, and was “picture perfect.”

Rex Waldheim EVA.  Image:  NASA

Rex Walheim, attached to a foot restraint on the station’s robotic arm, carries a large nitrogen tank assembly — used for pressurizing the station’s ammonia cooling system — during the second EVA of the mission.

Hans Schlegel & Columbus

Hans Schlegel, from Germany, works on the the new Columbus science module during STS-122’s second EVA.

Tani haircut.  Image:  NASA

Dan Tani gives himself a haircut with the ISS’s specialized hair clippers that includes a suction hose to collect the hair. Tani is getting ready to return home after a four month stay on board the ISS.

Columbus Inside.  Image:  NASA

Leopold Eyharts, Expedition 16 flight engineer, holds a panel inside the newly attached Columbus laboratory of the ISS. The panel bears the names of European engineers who built Columbus.

ISS & STS-122 crew

A group photo of the Expedition 16 and STS-122 crews. From the left (bottom) are NASA astronaut Steve Frick, STS-122 commander; and Peggy Whitson, Expedition 16 commander. From the left (middle row) are NASA astronaut Daniel Tani, STS-122 mission specialist; European Space Agency (ESA) astronaut Leopold Eyharts, Expedition 16 flight engineer; and cosmonaut Yuri Malenchenko, Expedition 16 flight engineer representing Russia’s Federal Space Agency. From the left (top row) are NASA astronaut Stanley Love, ESA astronaut Hans Schlegel, NASA astronauts Leland Melvin, Rex Walheim, all STS-122 mission specialists; and Alan Poindexter, STS-122 pilot.

Mission Control.  Image:  NASA

And let’s not forget all the people back on the ground who make the space missions possible. This is a photo in Mission Control, Houston, of the Orbit 1 team for the STS-122 flight.

Rex Walheim 3rd EVA.  Image:  NASA

Rex Walheim squints in the sunlight during the third and final EVA of the STS-122 mission.

ISS View. Image:  NASA

A view of the new configuration of the ISS, as the shuttle backs away from the station after undocking. The newest addition to the station, the Columbus science module, is visible, all shiny and new, on the upper part of the station, just under the Canadarm 2 robotic arm.

Shuttle Crew Says Goodbye, Undocks from ISS


After a successful visit to the International Space Station, the crew of space shuttle Atlantis said farewell and undocked from the station at 4:24 am EST Monday morning. Their busy nine-day stay included three spacewalks and the installation of the European Columbus science module, as well as a switch-out in crew. European astronaut Leopold Eyharts stays on the ISS while US astronaut Dan Tani returns home after a four-month expedition on the station.

“We just wanted to thank you again for being a great host and letting us enjoy your station for about a week,” shuttle commander Steve Frick radioed to the ISS before undocking. “We had a great time over there, we learned a lot and we really, really enjoyed working with your crew, one quarter of which we have here and we’re happy to take Dan home. But just again, to you and to Yuri and to Leo, thanks very much.”

“Well thank you guys,” station commander Peggy Whitson replied. “It’s a great new room you’ve added on and we really appreciate it. Get Dan home safe, and thanks!”

In an emotional farewell ceremony on Sunday, Tani reflected on his extended mission. The delay of Atlantis’ mission due to fuel sensor problems made his stay in space almost two months longer than originally planned. During his time on the station, Tani’s mother, who he called his “inspiration” was killed in a car accident. He said he can’t wait to get back home to be with his family.

But his recent experiences have given him great hope for the future.

“Today I feel very optimistic about our space program and our society because I’m here, I’ve spent time with a man from France, from Italy and from Germany and from Russia,” he said. “Nations that have not always been friendly are now cooperating and we’re doing great things.”

With shuttle pilot Alan Poindexter at the controls, the shuttle did a one-loop fly around of the station before departing. Atlantis’ crew is inspecting the shuttle’s heat shield to get the final OK for landing, which is scheduled for shortly after 9:00 am Wednesday morning, if the weather holds in Florida. Both the Kennedy Space Center and the backup landing site in California will be ready as NASA wants the shuttle to land that day to give the military enough time to destroy a damaged spy satellite.

The next shuttle flight is coming right up. Endeavour began its crawl to the launch pad early Monday in to prepare for a March 11 liftoff.

North American residents with clear skies Monday evening should be able to see both Atlantis and the ISS flying in tandem. See NASA’s orbital tracking site or Heaven’s Above for sighting times for your area.

I Heart the ISS: Ten Reasons to Love the International Space Station

The International Space Station. Image Credit: NASA

It’s been called a white elephant, an orbital turkey, a money pit, and an expensive erector set. Seemingly, there’s even people at NASA who think building it was a mistake. The International Space Station has been plagued with repeated delays, cost overruns, and bad press. Additionally, the ISS has never really caught the fancy of the general public and most likely there’s a fair percentage of the world’s population who have absolutely no idea there’s a construction project the size of two football fields going on in orbit over their heads.

But I’m going to be honest. I’ll come right out and say it: I really like the ISS. In fact, I’m crazy about it, and have been ever since Unity docked with Zarya back in 1998. Yes, my heart belongs to the space station, and since its Valentine’s Day, I’m going to profess my feelings here and now with ten reasons why I love the International Space Station:
(In no particular order:)

1. International Cooperation. Didn’t your heart swell with pride for the Europeans when the Columbus science module finally became part of the station this week? And you gotta love the Canadians for their reliable, heavy-duty Canadarm 2. The Russians have been steady partners in station construction and re-supply for years now. Japan’s science lab will be added on the next shuttle mission.

The ISS is the largest, most complex, international engineering project in history. In a world where violence and political animosity floods the daily news, it’s incredible that this structure is quietly being built by 16 different countries working together in relative harmony. If not for the international partners, the ISS probably wouldn’t have gotten off the ground. NASA Administrator Mike Griffin has said that the station’s most enduring legacy is the international partnership that created it.

2. Actually Building an Outpost in Space. The dream of almost every post-Apollo space enthusiast is to have a settlement or colony in space. As humble as it is, the ISS is exactly that. Humans have been living on board the station for over 7 years now. The experience of constructing and living aboard this complex structure in space is invaluable, and any future outpost will benefit from what’s been learned with the ISS.

ISS Crew & STS-120 Crew.  Image Credit:  NASA

3. The Personalities. Peggy Whitson, the first female station commander. Clay Anderson’s unique sense of humor. Suni Williams’ marathon and haircut for cancer patients. Mike Lopez-Alegria’s music. Mikhail Tyurin’s golf shot. Yuri Malenchenko’s wedding. Frank Culbertson’s September 11 perspective. Yury Usachev’s spinning antics. It goes all the way back to the three-way fist pump on Expedition One between Bill Shepherd, Sergei Krikalev, and Yuri Gidzenko. With the Expeditions lasting 4-8 months, we have the opportunity to get to know the astronauts and cosmonauts that live and work on board the ISS. If you watch the daily feeds from the ISS or listen to the periodic press conferences, you can become familiar with the different personalities of the station crews. The number one personality has to be Don Petit and his Saturday Morning Science.

4. You can see it almost every night. I’ve witnessed jaws dropping and eyes widening in wonder when people see the ISS for the first time gliding silently and swiftly across the night or early morning sky. I never tire of observing it. Find out when the station will fly over your backyard at NASA’s website or at the Heaven’s Above website.

5. No major problems so far. One of the real impressive things about the ISS is that all the components, built by different countries and contractors have fit together perfectly. Yes, there have been intermittent computer issues, a faulty smoke alarm and the torn solar arrays. But these problems have all been resolved in short order. The damaged SARJ (Solar Alpha Rotary Joint) is a looming issue that could be problematic. But there are some first-rate engineering minds working on this matter, and it appears they have time to come up with a solution. The station has never had a major calamity or had to be evacuated in over 7 years of continuous human occupation. Knock on a Whipple Shield.

6. The general public can participate. Schools and informal education centers can conduct live question and answer sessions with space station crews. Middle school students can choose locations on Earth for the ISS crew to take pictures as part of the EarthKAM project. Ham radio operators can talk regularly with astronauts and cosmonauts with the ARISS (Amateur Radio on the ISS.) College students can design projects to be researched on board the station. And of course if you have $40 million in spare change you can ride to the ISS on a Soyuz as a spaceflight participant.

7. Finally, we have science officers. The other dream of every post-Apollo space enthusiast (and Star Trek fans) is to have science officers to conduct real scientific research. The ISS has had science officers since 2002, but science hasn’t been in the forefront of the work on board the ISS. Yet.

8. Long term research. The ability of the ISS to serve as a platform for science has come under fire. But what other lab has been expected to produce scientific results while still under construction? With the addition of the European and Japanese science labs, and the expected increase in crew size from three to six in 2009, scientific research, the original purpose of the station, will finally be able to be conducted with consistency. The microgravity environment of the ISS allows the study of long-term effects of weightlessness on the human body, crucial for any future human exploration on the moon and Mars. Research will help fight diseases such as diabetes, cancer, osteoporosis, and AIDS. The station provides a unique place to test technologies such as life support systems and new manufacturing processes, and gives us a long-term platform to observe and understand Earth’s environment and the universe.

9. Post docking fly-arounds. After each construction mission to the ISS, the shuttle’s post docking fly-around gives us a chance to see the new additions and latest configuration of the station. The astronauts say it’s a thrill to see how their handiwork on a specific mission fits into the big picture of the entire ISS, and it’s a thrill for us back on Earth to see the station’s new look, too. Plus the fly-around usually gives the shuttle pilot some actual stick time to fly the shuttle and a little time in the limelight.

10. What else would we be doing? Some people feel that the ISS’s tremendous budget has taken funds away from robotic exploration and other science. I can’t argue with that. But when it comes to human spaceflight, what else would we have been doing for the past 10-20 years? A space station was the logical next step after the shuttle. The main problem is that it took so long to decide on a plan, get it approved by Congress and get it in the works with international cooperation. But now, with construction and maintenance ongoing, we’re constantly and continually learning how to live and work in space. The ISS is a resource that will guide us on our future human endeavors in space. It’s more than just an obligation to finish and then be disregarded. The planning and funding for its future should encompass the maximum utilization of its fullest potential.

In my eyes, the International Space Station is a thing of beauty, a work of art, an engineering marvel, and a constant companion that I watch for every night as it orbits our planet. The ISS should be given all the respect — and love — it deserves.

STS-122 Space Shuttle Mission Rockets to Space


Defying a bleak weather forecast, space shuttle Atlantis rocketed into space on Thursday, February 7, on its way to the International Space Station with a new science laboratory. The STS-122 mission had been delayed by a faulty fuel sensor, and was originally scheduled to launch last December. But today there were no problems with the sensor during fueling and the shuttle lifted off flawlessly at 2:45 p.m. EST. On board is a seven member crew and the European Space Agency’s $1.9 billion Columbus science module, Europe’s main contribution to the ISS. Atlantis will rendezvous with the station on Saturday, Feb. 9. The launch came seven years to the day after Atlantis carried NASA’ science laboratory named Destiny to the space station.

“It was a pretty clean launch,” astronaut Jim Dutton radioed the shuttle crew from mission control following the launch. “We did see, at about MET 2:13 (two minutes and 13 seconds after launch) a few piece of debris, they think at least three, that came off inboard of the LO2 (liquid oxygen) feedline just aft of the starboard bipod leg. The debris assessment team indicated they didn’t identify an impact at the time and it’s obviously under evaluation.”

The crew of Atlantis will now check out its systems and inspect the heat shield while chasing down the space station. There will be three spacewalks during the flight so astronauts can attach the Columbus lab and connect its power and fluid lines.

Atlantis’ liftoff came despite concerns that a weather front would interfere with the launch. But the weather cooperated for an on-time launch.

Installing Columbus, named after the 15th-century Italian explorer, is the main task for the 121st space shuttle mission.

“Columbus has discovered a new world, and I think that with Columbus we are discovering a totally new world,” Jean Jacques Dordain, ESA’s director general, said after the launch.

Atlantis’ seven-member crew includes two Europeans, Germany’s Hans Schlegel and France’s Leopold Eyharts. US astronauts are Commander Steven Frick, pilot Alan Poindexter, and mission specialists Leland Melvin, Rex Walheim, and Stanley Love.

“It’s great to have two laboratories in space,” said Bill Gerstenmaier, NASA’s associate administrator for space operations.

The mission is scheduled to last 11 days.

Original News Source: NASA Press Release

Tricky January 30 Spacewalk to Repair ISS Solar Array


Space station astronauts will conduct a spacewalk on January 30 to replace a faulty positioning motor at base of the station’s two starboard solar arrays. ISS Expedition 16 commander Peggy Whitson and flight engineer Dan Tani will change out the motor in hopes of regaining more power-generating ability of the orbiting laboratory’s expansive solar wings. But the astronauts will have to work fast, since they can only work on the electricity-producing arrays when the sun isn’t shining on them. That only allows 33 minute increments of time to conduct the repairs.

Because of the faulty motor, the solar arrays have been unable to track the sun continuously since early December, when the joint motor suffered a series of electrical shorts. In an earlier spacewalk, Tani and Whitson surveyed the damage and ruled out meteorite damage to the motor. Without the repair, the space station would have enough power to make it through at least the next shuttle mission, currently scheduled for a Feb. 7 launch, but not much further said Kirk Shireman, NASA’s ISS deputy program manager.

If the Wednesday spacewalk is successful, the ISS will have power to last through the planned arrival of a massive Japanese laboratory in April and into the summer, Shireman added.

The broken motor controls a beta gimbal joint that pivots one of the station’s two starboard solar wings to face the sun. NASA hopes replacing the whole motor, a garbage-can sized device that weighs about 250 pounds (113 kilograms), with a backup will fix the problem. The replacement motor was already on board the station, brought up on an earlier flight.

For safety reasons, the astronauts can only work while orbiting on the night side of Earth. If the sun was shining on the solar panels while Whitson and Tani were working on the joint, they would be at risk of shocks due to the high power levels surging through the arrays. They will only have about 33 minutes of total “shadeâ€? at a time to conduct their work. If they can’t replace the motor during one night side pass, they’ll have to wait and finish their task on the next pass. The station continuously orbits the Earth every 90 minutes.

NASA officials said the repair is possible to do in one 33 minute segment, but only if everything goes as planned. Since the damage only occurred recently, Whitson and Tani have not rehearsed the spacewalk in the Neutral Buoyancy Lab in Houston, a giant swimming pool where astronauts train for spacewalks. However, other astronauts on the ground have rehearsed the repair and shared their insights with the astronauts on board the ISS.

Wednesday’s EVA will be the sixth career spacewalk for both Whitson and Tani, and the fifth for the station’s Expedition 16 crew.

This spacewalk is unrelated to on-going analysis of problems with a massive Solar Alpha Rotary joint on the right side of the station’s main power truss that is needed to turn outboard arrays to track the sun. Astronauts discovered metal shavings in the gear’s attached metal ring during past spacewalks, and engineers do not yet understand the cause of the unusual erosion. Whitson and Tani will take another look at the 10-foot (3-meter) wide gear if they have extra time during Wednesday’s excursion, mission managers said.

NASA will broadcast the Expedition 16 crew’s fifth spacewalk live on NASA TV beginning at 4:00 a.m. EST (0900 GMT) on Jan. 30.

Original News Source: NASA TV,