STS-134 Mission Preview

CBS News

KENNEDY SPACE CENTER, FL--With just two flights remaining and thousands of layoffs looming, NASA is readying the shuttle Endeavour for launch Friday on its 25th and final mission, a four-spacewalk voyage to deliver supplies, spare parts and a $2 billion particle physics detector to the International Space Station.

Playing out against a backdrop of uncertainty about the future of American manned space flight, Endeavour's launch on NASA's next-to-last shuttle flight has generated intense public interest in the wake of a Jan. 8 assassination attempt that left Rep. Gabrielle Giffords, wife of shuttle commander Mark Kelly, gravely injured with a gunshot wound to the head.

The shuttle Endeavour atop pad 39A. Launch on the shuttle's 25th and final mission is targeted for April 29. (Credit: William Harwood/CBS News)

Recovering in Houston, Giffords faces a long, difficult rehabilitation and an uncertain prognosis. But Kelly says his wife is making steady progress and will attend the launching in Florida. When told her medical team had approved the trip, Kelly told the CBS Evening News, she pumped her fist and said "awesome."

Joining the national surge of interest in Giffords' story and Kelly's decision to remain in place as Endeavour's commander, President Barack Obama and his family also plan to attend the launching, making him only the third sitting president to witness a manned space launch.

Giffords, her entourage and the First Family will watch from a secure location near the launch control center 3.4 miles from launch pad while several hundred thousand area residents and tourists jam nearby roads and beaches for a chance to see one of NASA's final two shuttle launchings as the 30-year-old program draws to a close.

"It's been an incredible success over a long period of time and it brings a capability that certainly we're not going to replace with the next vehicle," Kelly said. "So it's sad to see it go. (But) I think it's probably the right time to retire the shuttle and move on to something else so we can get out of low-Earth orbit and start to explore the solar system again."

Using a repaired external tank that was damaged during Hurricane Katrina, Endeavour's launch on the 134th shuttle mission is targeted for 3:47:52 p.m. EDT on Friday, April 29, roughly the moment Earth's rotation carries pad 39A into the plane of the space station's orbit. To catch up with the lab complex, the shuttle must take off within five minutes of that "in-plane" moment.

Joining Kelly on Endeavour's upper flight deck will be pilot Gregory "Box" Johnson, European Space Agency flight engineer Roberto Vittori and Michael Fincke, a space station veteran who has logged nearly a full year in space during two earlier expeditions aboard the space station.

Strapped in on the shuttle's lower deck will be station veteran Gregory Chamitoff and Andrew Feustel, who helped repair the Hubble Space Telescope during a 2009 shuttle mission. All six shuttle fliers are space veterans, but it's the first shuttle flight for Fincke, who rode Russian Soyuz spacecraft for his first two missions.

Lost in the glare of the Giffords story, Endeavour's mission is among the most ambitious of the final half-dozen or so flights to complete the assembly of the International Space Station. Carrying 15 tons of cargo, shuttle mission STS-134 will complete the U.S. segment of the lab complex after 12 years of construction. A final flight by the shuttle Atlantis in late June is devoted primarily to stocking the lab with supplies.

"It is an extremely complex mission," said shuttle Program Manager John Shannon. "It's a long period of time docked to the station, four EVAs, a tremendous amount of activity internal to the ISS, we're going to put a world-class experiment on the ISS and get it all hooked up.

"I think the missions we are executing now in complexity are the most difficult missions that not just NASA, but any nation has ever flown in space. And I would include Apollo in that discussion. I think the missions we do right now are more complicated than what we were doing even during the moon landings."

The Endeavour astronauts. Left to right: Pilot Gregory Johnson, Michael Fincke, Gregory Chamitoff, commander Mark Kelly, Andrew Feustel and Roberto Vittori. (Credit: NASA)

Assuming an on-time liftoff, Kelly plans to guide Endeavour to a docking at the space station's forward port around 1:25 p.m. on May 1. A pallet of spare components will be robotically bolted to left side of the station's power truss a few hours later. The next day, the 7.5-ton Alpha Magnetic Spectrometer will be attached to the right side of the power truss.

Using a massive magnet to bend the trajectories of high-energy cosmic rays -- charged particles from supernovas, neutron stars, black holes and other cosmic enigmas -- scientists will look for evidence of antimatter and as-yet-undetected dark matter, believed to make up a quarter of the mass of the universe.

AMS may even find evidence of strange particles made up of quarks in different arrangements than those found on Earth. Or something completely unexpected.

The AMS "really probes the foundations of modern physics," said Sam Ting, a Nobel Laureate who manages the multinational experiment. "But to my collaborators and I, the most exciting objective of AMS is to probe the unknown, to search for phenomena which exist in nature but yet we have not the tools or the imagination to find."

AMS will operate autonomously after it is connected to station power, beaming down a continuous stream of data for at least 10 years and possibly longer if the lab is funded past 2020.

With AMS in place, Fincke, Feustel and Chamitoff, working in alternating two-man teams, plan to carry out four spacewalks May 3, 5, 7 and 9 to retrieve one materials science exposure experiment and to install another; to refill the ammonia coolant reservoir in the station's far left-side solar array; to re-lubricate a solar array rotary joint; to install a robot arm attachment fitting on the Russian Zarya module; and to perform needed maintenance.

They also plan to test an innovative new technique for removing nitrogen from their bloodstreams prior to one spacewalk, a protocol to prevent the bends that is less time consuming and potentially disruptive than the established technique.

If all goes well, Endeavour will undock from the station around 6:18 p.m. on May 11. Then, testing new sensors and software under development for NASA's Orion deep space exploration capsule, the shuttle crew will re-rendezvous with the station, pulling within about 1,000 feet before breaking off and departing the area.

Landing back at the Kennedy Space Center is targeted for 9:22 a.m. on Friday, May 13. But if Endeavour is in good shape after docking, NASA managers plan to extend the flight one or two days to give the crew more time to help their station colleagues with needed maintenance. If two days are added, the landing would be expected around 8:40 a.m. on May 15.

It is not yet known where President Obama, his family or Giffords will view the launching. NASA normally reserves the top floor of a United Space Alliance office building near the huge Vehicle Assembly Building for guests of the agency administrator, providing an unobstructed view of the launch pad a few miles away.

President Bill Clinton and wife Hillary watched the launch of former Sen. John Glenn aboard the shuttle Discovery in 1998 from the roof of the nearby launch control center where the families of shuttle crews typically gather.

In any case, NASA and Brevard County officials are bracing for large crowds as tourists and area residents turn out to witness the shuttle program's next-to-last launching. During Discovery's final launch in February, tourism officials estimated more than 300,000 shuttle watchers jammed area roads an beaches, generating major traffic jams across the county.

Even larger crowds are expected for Endeavour's launching. If bad weather or technical problems delay launch inside of four hours, NASA managers may be forced to order a 48-hour slip because of expected traffic snarls that would make it difficult for engineers to "safe" the shuttle, get home for needed rest and then get back to the space center in time for a 24-hour recycle.

Obama's presence for Endeavour's launching is fitting, not just to show support for Kelly and Giffords as she continues her difficult recovery, but also because of his administration's drive to reshape America's manned space program.

Engineers connect a gaseous hydrogen vent line to Endeavour's external tank after rollout to pad 39A. (Credit: William Harwood/CBS News)

While expressing support for the Bush administration's post-shuttle moon program during the 2008 presidential campaign, Obama has since ordered NASA to scrap the Constellation program and to focus instead on helping private industry develop commercial space taxis to ferry U.S. astronauts to and from low-Earth orbit after the shuttle fleet is retired.

At the same time, the administration gave into congressional demands for immediate work on a new-heavy lift rocket to propel new crew capsules like Lockheed Martin's Orion spacecraft, originally designed for moon missions, on deep space voyages to nearby asteroids and, eventually, Mars.

But exploration is a long-term goal and the targets and mission architectures are not yet defined. In the near term, the focus is on operating the space station, retiring the shuttle and developing commercial manned spacecraft to take it's place.

It will take private industry at least three to four years to develop new orbital spacecraft and until then, NASA will be forced to rely on Russian Soyuz vehicles, at an average cost of about $55 million a seat, to get astronauts to and from the station.

While many NASA insiders agree with the need to replace the space shuttle with a less expensive more up-to-date spacecraft, virtually everyone laments the political decisions and compromises that resulted in a multi-year gap between the shuttle's retirement and the debut of whatever vehicle will replace it.

As it is, the shuttle's highly trained work force is being phased out as NASA winds down the program.

Through earlier layoffs and attrition, United Space Alliance, the shuttle prime contractor, has reduced its workforce in Florida, Texas and Alabama from around 10,500 in October 2009 to a current level of around 5,600. In late July or early August, the company will implement another major reduction, eliminating between 2,600 and 2,800 jobs across the company. Of that total, 1,850 to 1,950 job losses are expected in Florida, 750 to 800 in Texas and 30 to 40 in Alabama.

"We have been stepping down our workforce over the last, really, three years," Shannon told reporters last month. "Back in late 2006, the shuttle program had 14,000 contractors. We're currently down to just over 6,000 contractors. We had 1,800 civil servants at that time, we're just over 1,000 at this time.

"So it's been this gradual phase down. We're at a point now where it's primarily operations and sustaining engineering for the different elements that are left, and we require those out to the end of the program."

And the end is clearly at hand.

Only two more shuttle flights are on the books -- Endeavour's mission and a final flight by the shuttle Atlantis in late June. A small transition team, made up of only a few hundred managers and engineers, will be responsible for decommissioning the orbiters after their final flights, removing components that might be used in follow-on programs and preparing the ships for eventual museum duty.

Discovery will be sent to the Smithsonian Air and Space Museum's Steven F. Udvar-Hazy Center near Washington. Atlantis will remain at the Kennedy Space Center and Endeavour will be displayed at the California Science Center in Los Angeles.


In January 2004, responding to a recommendation from the Columbia Accident Investigation Board, President Bush ordered NASA to complete the International Space Station and retire the shuttle fleet by the end of fiscal 2010. The president said the money saved would help finance development of new rockets and spacecraft designed to carry astronauts back to the moon by around 2020. The goal was the establishment of Antarctica-style lunar bases.

NASA managers then prioritized the remaining shuttle payloads to ensure completion of the space station with a reduced number of flights. One payload -- the Alpha Magnetic Spectrometer -- was dropped from the manifest to make room for more critical space station components.

Ting and the project's supporters never gave up hope and even while developing plans for the possible use of an unmanned rocket, they continued lobbying for an additional shuttle flight to ferry the particle detector to the space station. Their arguments swayed several key lawmakers, including Sen. Bill Nelson, a Florida Democrat who flew aboard the shuttle in 1986.

During a swing through Florida in the midst of the 2008 presidential campaign, Obama said he would support an additional shuttle flight as well as the Constellation moon program NASA was developing to carry out the Bush administration's 2004 directives.

After the election, Obama came through on his promise to add an additional shuttle flight to ferry AMS into space. But the administration chartered a blue-ribbon panel in 2009 to re-assess NASA's manned space program in light of lower long-range budget projections.

When all was said and done, Obama ordered NASA to stop work on Constellation and to focus instead on development of private-sector rockets and a new heavy-lift system for deep space exploration. He also approved a five-year extension to keep the space station operational through 2020.

When AMS was designed, the instrument featured a powerful cryogenically cooled superconducting magnet. Designed to operate for three years, NASA originally planned to bring the detector back to Earth when it ran out of coolant, making space for a follow-on experiment.

When AMS was put back on the post-Columbia manifest, it was penciled in as the last mission. But planners revised the schedule to maximize space station resupply and AMS ended up scheduled for launch in July 2010. A final flight by the shuttle Discovery was planned for the following September.

In late 2009 and early 2010, when it was becoming clear the administration was going to support a five-year extension to the life of the space station, Ting began re-thinking the AMS mission. The cryogenically cooled magnet, while more powerful than an uncooled magnet used during an AMS test flight, would run out of coolant in three years.

By switching back to the uncooled magnet and adding additional detectors and computer processors, the team could achieve the same resolution as the super-cooled magnet. And the uncooled magnet could operate through the life of the space station.

"We had built a superconducting magnet based on the assumption ... that we would be on space station for three years and space station would be deorbited in 2015," Ting said. "So we test the magnet. The magnet would last 28 plus or minus six months, close to three years. But now at the end of last year (2009) we learned space station would go to 2020 and maybe even go to 2028. So after three years, AMS would become a museum piece. And so we quickly decided to change to a permanent magnet."

The permanent magnet, which flew a test mission aboard the shuttle in 1998, is five times less powerful than the superconducting magnet originally envisioned. But it requires no maintenance and testing shows its magnetic field has not changed in 12 years.

Because of the weaker field, "we put in more detectors ... to increase the measurement accuracy," Ting said. "And so the detector resolution with the permanent magnet is not compromised."

Physicist Sam Ting discusses the Alpha Magnetic Spectrometer with reporters in the Space Station Processing Facility. (Credit: Wiliam Harwood/CBS News)
Replacing the magnet and adding the additional detectors forced NASA to delay Endeavour's launch until after Discovery's flight, first to November, then December and eventually February. Then, problems with suspect ribs, or stringers, in Discovery's external tank ultimately delayed that flight to February 2011 and Endeavour's launch to mid April.

While all of that was going on, NASA managers were lobbying for permission to convert a stand-by launch-on-need rescue flight for Endeavour's crew into a full-blown space station mission to deliver a final load of supplies. That flight, by the shuttle Atlantis, is scheduled for launch June 28. While a dedicated rescue flight will not be available for Atlantis' crew, NASA developed plans for the three-man one-woman crew to fly back aboard Russian Soyuz spacecraft if anything goes wrong with Atlantis.

Funding for the Atlantis mission was included in the compromise continuing resolution that is keeping the government in operation through the end of fiscal 2011.

Atlantis will use an external tank that is similar in design and history to the one used by Discovery. The aluminum alloy used in that tank's stringers was from a batch that did not meet strength requirements. Built-in stress, coupled with exposure to cryogenic temperatures during fueling, caused cracks to develop, requiring extensive repairs.

Similar repairs have been carried out on the tanks used by Endeavour and Atlantis. But Endeavour's tank is of a different vintage.

"ET-122 was in one of our production cells down at Michoud (Louisiana) when Hurricane Katrina hit and several small chunks of concrete were dislodged from the room and fell on the tank, damaging the foam," Shannon said. "We kind of put that tank to the side while we were doing normal processing.

"I asked the team several years ago to go back and look at ET-122 and see if it was a viable flight tank. All the foam in that area was dissected. The LOX tank, they did eddy current (testing), they did all kinds of non-destructive analysis on it. It was a very good tank, so they replaced that foam, they went to the intertank area, there was one stringer that had been nicked, they took that stringer off, put a new one on, re-foamed that area."

The foam insulation on the tank is nearly 10 years old. To make sure it was still up to the rigors of launch, "they did pull tests all over the tank, they did assessments to make sure it's a good tank and safe to fly," Shannon said. "Then they did all of the return-to-flight modifications that we had done on tanks after Columbia."

"We have a lot of confidence in ET-122," he said. "It doesn't look real pretty because we did some foam patches, it looks a little more like the hail-damaged tank that we flew, which I think was ET-120. But from all out testing and experience, we have high confidence in that tank."


At the start of 2011, as NASA was closing in on the root cause of the cracks in Discovery's tank, the agency was rocked by news that Giffords, a Democrat representing Arizona's 8th Congressional District, had been shot in the head Jan. 8 at point blank range during a public meeting in front of a Tucson supermarket.

Giffords was one of 20 people hit when Jared Loughner, a 22-year-old college dropout, allegedly opened fire with a semi-automatic pistol. Six were killed, including a federal judge and a 9-year-old girl.

"It was extremely terrible," said Johnson, Endeavour's pilot. "The news reports, for a period of time believed that (Giffords) had been killed. We had socialized as a crew just a few short weeks prior, and my daughter had spent some time with Gabby on a one-on-one level. She was devastated."

President Obama flew to Arizona for a memorial service, telling friends and family members "there is nothing I can say that will fill the sudden hole torn in your hearts."

A file photo of Rep. Gabrielle Giffords and shuttle commander Mark Kelly. (Credit: NASA)
"But know this: The hopes of a nation are here tonight. We mourn with you for the fallen. We join you in your grief. And we add our faith to yours that Representative Gabrielle Giffords and the other living victims of this tragedy will pull through."

One week after the assassination attempt, NASA announced that Kelly, who had flown to Tucson the day of the shooting, would be taking a leave of absence. Rick Sturckow, a veteran shuttle commander, took his place in crew training exercises and simulations.

But one month later, Kelly announced he would resume training to command Endeavour, saying his wife "would be very comfortable with the decision I made."

"Her days are filled, from the time she gets up at eight o'clock until after 6 p.m., with six hours of speech, occupational and physical therapy," Kelly told reporters in March. "So she's got very busy days, and meals in between.

"And I started to think about STS-134, about the mission, my crew, the fact that I've been training for it for nearly a year and a half. And considering a bunch of other factors, including what Gabrielle would want me to do and what her parents and her family and my family would like, I ultimately made the decision that I would like to return and command STS-134."

Chief astronaut Peggy Whitson supported Kelly's decision.

"Mark had to make the first part of this decision," she said. "We weren't going to ask him to command 134 unless he felt comfortable and ready to do that. In addition to feeling comfortable, he has an incredible support group, which made us more comfortable with the fact that he had folks to help him through this process and that it would make it a doable thing for him to perform the mission."

Asked about critics who might question his decision to spend time away from his wife at a critical point in her recovery, Kelly said "they don't understand a few things."

"They don't know her very well, so they don't know what she would want," he said. "She is a big supporter of my career, a big supporter of NASA. She really values the mission of NASA. What we do and what the nation gets from that are very high on her list of things she really treasures about this country. So I think they don't understand that, and they also don't understand her condition or the support system that I have in place.

"I think if they had more details about those things, you'd probably have less people being critical. But I think in any decision there's a lot of interest in, you're going to have people on both sides."

Kelly told the CBS Evening News the week before launch that Giffords was "very excited" about the pending trip to Florida.

"It's going to be a little bit more complicated than your average person," he said. "But I've got folks in my office that have been focused on that. And, you know, she has some security and certainly there are some medical needs that need to be met, but we've been planning it for a couple weeks now. It's not anything too significant."

Kelly said earlier he still feels angry from time to time about what happened to his wife and the other victims of the Tucson shootings.

"When a traumatic event happens, there are those different steps that you go through," he said. "I think I very quickly got to 'angry' on the first day this happened. I can't remember what step two was, but I think I skipped right over that one. At times, I'm angry about what happened to her. ... It's really an unfortunate, tragic situation."

But he said that anger played no role in his decision to resume training.

"Absolutely not," he said. "What I use to evaluate whether I want to come back to be commander of this mission has nothing to do with being angry and everything to do with what is right for NASA first, and then for me and my family."


Endeavour's initial launch window opens April 29 and extends through May 4. If the shuttle is not off the ground by then, the team will stand down for three days to reload liquid oxygen and hydrogen fuel cell reactants and to give the Air Force time to launch an Atlas 5 rocket carrying a missile early warning satellite. The shuttle launch window would re-open around May 8 and extend through May 29.

NASA had planned to launch Endeavour on April 19, but earlier this month the fight was delayed 10 days because of a conflict with the launch and docking of a Russian Progress supply ship. The delay put the shuttle launch on the same day as the British royal wedding of Prince William and Kate Middleton.

Asked if NASA considered an additional delay to avoid a conflict with the royal wedding, Bill Gerstenmaier, chief of space operations for NASA, said "we work beta (angle) constraints and we work launch range constraints. I haven't yet put on our manifest charts 'wedding constraints.' So we didn't factor that into our thinking."

As with all post-Columbia flights, Endeavour's ascent will be monitored by batteries of launch pad cameras, radar and long-range trackers, on the lookout for any signs of foam insulation falling from the external tank that could damage the shuttle's fragile heat shield.

Debris poses the biggest threat during the first two minutes and 15 seconds of flight when the dense lower atmosphere can cause lightweight insulation to come to a near standstill in a fraction of a second. The accelerating space shuttle can then slam into it at a high relative velocity.

A phenomenon known as "cryo pumping" can cause foam to pop off later in ascent when liquefied air trapped under the foam near the top of the liquid hydrogen tank warms and expands as the fuel level drops during the climb to space. But testing and flight experience show cryopumping typically happens well after the aerodynamically sensitive period.

The shuttle Endeavour's external tank heads for the Vehicle Assembly Building. Light colored foam insulation indicates an insulation repair site. (Credit: William Harwood/CBS News)

Given the history of Endeavour's "hurricane tank," mission managers expect to see more foam insulation falling away during the climb to space than usual because not all of the post-Columbia tank improvements were carried out for the repaired tank.

"This tank doesn't have some of the modifications to it that other tanks have had, so we expect to see some foam loss," Gerstenmaier said. "If you remember, we used to lose foam around the LH2 ice frost ramps on the hydrogen tank because there was a little alignment pin that would allow some cryo pumping and ingestion around the ice frost ramps which could cause some foam to come off in those areas.

"We fully expect this to occur on this tank," he said. "It'll again be late losses of foam, but we expect to see some foam losses in that area."

Kelly and company plan to close out their first day in space setting up a computer network, downlinking photos of the external tank, breaking out equipment and testing the ship's robot arm.

The next day, Johnson, Fincke and Vittori will use the robot arm and an instrumented extension boom to carry out a detailed inspection of Endeavour's reinforced carbon carbon nose cap and wing leading edge panels to make sure the most critical elements of the shuttle's heat shield came through the climb to space in good shape. Laser scans and high-resolution photographs will be beamed down to NASA's Damage Assessment Team for detailed analysis.

While the heat shield inspection is underway, Fincke, Feustel and Chamitoff will check out their spacesuits and the tools they'll use during the mission's four spacewalks. The crew also will break out and test the rendezvous tools they will use during final approach to the space station.

The terminal phase of the rendezvous will begin about three hours before docking on fight day three when Kelly and Johnson will fire the ship's maneuvering jets to begin closing the final nine miles between the two spacecraft. Approaching from behind, Kelly will pause at a point 600 feet directly below the space station. He then will oversee a slow computer-assisted back flip maneuver that will expose the orbiter's belly to the station.

As black heat shield tiles on the shuttle's underside come into view, station flight engineer Paolo Nespoli and Catherine "Cady" Coleman, working in the Russian Zvezda command module, will snap hundreds of photographs using cameras equipped with 400-mm and 800-mm telephoto lenses capable of spotting even minor damage and defects.

With the rendezvous pitch maneuver complete, Kelly will manually guide Endeavour up to a point about 400 feet directly in front of the station with the shuttle's nose pointed toward deep space and it's open payload bay facing the lab's forward port. With the two spacecraft flying in formation at more than 5 miles per second, Kelly will carefully move in for a docking.

Joining Nespoli and Coleman to welcome the shuttle crew aboard will be Expedition 27 commander Dmitri Kondratyev, Ronald Garan and Russian cosmonauts Andrey Borisenko and Alexander Samokutyaev.

After a brief "meet and greet" in the forward Harmony module, the shuttle crew will get a routine safety briefing before splitting up and getting to work.

The major item on the post-docking agenda is installation of External Logistics Carrier No. 3 on the upper left side of the station's power truss.

Mounted in Endeavour's cargo bay just in front of the Alpha Magnetic Spectrometer, ELC-3 tips the scales at just over 14,000 pounds, loaded with large components that will become part of the station's extensive spare parts inventory for use down the road, after the shuttle fleet is retired. Three other ELCs were attached to the station during two earlier shuttle missions, two on the right side of the power truss and one on the lower left.

ELC-3 is carrying 10 spare remote power control module circuit breakers, two spare S-band antenna assemblies, an ammonia tank loaded with 600 pounds of coolant, a high-pressure oxygen tank for the station's airlock and a spare arm for a Canadian cargo manipulator that can be attached to the station's main robot arm. It is also carrying a suite of small military experiments.

Fincke and Vittori, operating the shuttle's robot arm, will pull ELC-3 from Endeavour's cargo bay three hours after docking and hand it off to Johnson and Chamitoff, operating the space station's robot arm. From there, the station arm will move ELC-3 to the upper attachment point on the port side of the power truss.

Once in position, a motorized clamp will lock ELC-3 in place and an umbilical will deliver power to component heaters and electronics.

Getting ELC-3 attached is "absolutely critical because there's no other way to get the big spares on board without the orbiter," said space station Flight Director Derek Hassmann. "It's amazing the amount of inventory we have on orbit in terms of critical pump modules, in terms of communications equipment, in terms of high pressure gas tanks for the airlock. I would say we're in an excellent position for shutle retirement. We've made tremendous progress over the past five or six years, first in identifying the plan and getting all the tons of hardware on orbit."

ELC-3 must be unloaded from the shuttle first because of center-of-gravity re-entry and landing constraints. If ELC-3 cannot be unberthed for some reason, the spare parts pallet and the AMS will be returned to Earth.

But no such problems are expected and if all goes well, the astronauts will turn to their primary payload on flight day four.

Feustel and Vittori will pull the Alpha Magnetic Spectrometer out of the shuttle's cargo bay using Endeavour's robot arm. As with ELC-3, the AMS will be handed off to the station arm, operated by Johnson and Chamitoff. They will move the particle detector to the upper right side of the power truss and robotically lock it in place.

Power and data cables will be remotely connected. No other crew interaction is required and data collection will begin almost immediately.

"Not too long ago, Steve Hawking, a very well known physicist, came to spend an afternoon with me at Geneva (where we were) assembling the detector," Ting said. "He asked me a question. He said, why do you do AMS on the station, not with a satellite? I told him it's really not possible to do a very, very precise, very sophisticated state-of-the-art detector to study the origin of the cosmos without the space station. Because space station can provide support of large weight and enormous amount of power. So without a space station, AMS would not have been possible."

Using the same magnet that flew on a shuttle test mission in 1998, the AMS will record subtle shifts in the trajectories of incoming charged particles to look for evidence of antimatter left over from the big bang birth of the cosmos and to search for clues about the nature of mysterious dark matter and evidence for new forms of matter that have been predicted but never seen.

The Alpha Magnetic Spectrometer, circled in red in this computer graphic, on the International Space Station's right-side power truss. (Credit: NASA)

Built at CERN, the European Organization for Nuclear Research, and managed by the U.S. Department of Energy, the $2 billion AMS is an international collaboration between 16 nations, 60 institutes and some 600 physicists. Ting, a soft-spoken Chinese-American physicist who shared the 1976 Nobel Prize in physics, is a tireless advocate.

"The largest accelerator on Earth is 16 miles in circumference, the large Hadron Collider, LHC," he said. "In LHC there are four big experiments. Thousands and thousands of physicists work there trying to understand the beginning of the universe, what is the origin of mass, why different particles have different masses.

"The cost of ISS is about 10 times more than the LHC. The LHC has four experiments. On the space station, to study particle physics, the origin of the universe, (we only have) AMS. And that's why we're very grateful to the United States House of Representatives and the Senate, which passed the resolution to support NASA to have an additional flight to put us in space."

The Large Hadron Collider is capable of generating energies as high as 7 trillion electron volts. To put that in perspective, 1 trillion electron volts is roughly equivalent to the energy of a single flying mosquito. But in particle physics, that energy is concentrated in a single sub-atomic particle and particles from deep space can have energies as high as 100 million trillion electron volts.

"This means that no matter how accelerators are here on Earth, you cannot compete with the cosmos," Ting said.

One of the many mysteries AMS was designed to explore is what happened to the anti-matter that must have been created in the big bang. Scientists believe equal amounts of matter and anti-matter were produced, but a slight imbalance -- or some other factor -- resulted in a universe dominated by normal matter. Or at least a nearby universe made up of normal matter.

"If the universe comes from a big bang, before the big bang it is vacuum," Ting told reporters recently. "Nothing exists in vacuum. So in the beginning, you have (negatively charged) electron, you must have a (positively charged) positron so the charge is balanced. So you have matter, you must have antimatter, otherwise we would not have come from the vacuum.

"So now the universe is 14 billion years old, you have all of us, made out of matter. The question is, where is the universe made out of antimatter? With this experiment, the reason we designed it to such a large size with so many layers of repetitive position detectors is to search for the existence of antimatter to the age of the observable universe, anti-helium, anti-carbon.

"We can distinguish this particle from billions of ordinary particles," he said. "If you think about it, this is not a trivial job. In the city of Houston during the rainy season, you have about 10 billion raindrops per second. If you want to find one that's a different color, it's somewhat difficult. This illustrates the precision this detector is going to achieve."

Dark matter, the mysterious, as-yet-undetected material believed to provide the glue -- gravity -- needed to hold galaxies and clusters of galaxies together, is believed to make up a quarter of the universe compared to the 4 percent made up of the normal matter familiar to human senses. The rest is believed to be in the form of dark energy, a repulsive force that appears to be speeding up the expansion of the universe.

While AMS cannot directly detect dark matter, it can detect the particles that would be produced in dark matter collisions.

AMS also will be on the lookout for so-called "strangelets," sub-atomic particles made up of quarks in different combinations than particles found on Earth. There are six types of quarks -- known as up, down, top, bottom, charm and strange -- but protons and neutrons making up normal matter seen on Earth are made up of just two -- different combinations of up quarks and down quarks.

"The smallest particle are called quarks," Ting said. "We know six quarks exist. But it's very, very strange. All the material on Earth is made up of just two, up and down. We know in the accelerator, six types exist, but on Earth you only see the first two. So the simple question you want to ask is, where's the material made out of three types of quarks? Up, down and strange? It's a very simple question, but a very, very important question."

Whatever AMS discovers, scientists will have plenty of data to work with. Some 25,000 particle detections per second are expected when the instrument is up and running.

"We're gathering data at seven gigabits per second," said Trent Martin, the AMS project manager at the Johnson Space Center in Houston. "We can't send that huge amount of data down through the space station data system, it's just too much.

"So the onboard computers actually go through a process of condensing that data down to just the data that we're truly interested in, compressing it as much as possible. We send down data on average at about six megabits per second, constantly for the entire time that AMS is on. The computers can store up data and we can burst it down at a much higher rate."

Asked to speculate on what AMS might discovery, Ting declined, saying "Most physicists who predict the future normally end up regretting it."

"My responsibility and the responsibility of my senior collaborators is to make sure the instrument is correct," he said. "Because the detector is so sensitive, everything we measure is something new. We want to make sure it's done correctly."


A few hours after the AMS installation, Feustel and Chamitoff will seal themselves in the space station's Quest airlock and spend the night at a reduced pressure of 10.2 pounds per square inch. The "camp out" procedure is a standard protocol to help remove nitrogen from the spacewalkers' bloodstreams and prevent the bends when working in NASA's low-pressure spacesuits.

The primary goals of the first spacewalk are to retrieve a materials science space exposure experiment mounted on ELC-2; to install a replacement; and to hook up ammonia line jumpers to set up a pipeline from an ammonia coolant tank near the center of the power truss to the outboard left-side solar array.

The Materials International Space Station Experiments -- MISSE -- are the size of suitcases.

"It's a space exposure experiment," Chamitoff said in a NASA interview. "Basically they're like large suitcases with lots of samples inside, and those samples can be everything from materials to paints to coatings to electronic equipment to biological samples, and they can come from different organizations.

Astronauts Andrew Feustel and Gregory Chamitoff replace space exposure experiment packages during the mission's first spacewalk. (Credit: NASA animation)

"The idea is to expose these things to the harsh environment of space for a long period and see what happens -- if the seeds will still germinate, if a paint material will protect what's below it, see if a circuit can still work and to help us design better systems for the future.

"There are two experiments out there that are a part of MISSE 7," Chamitoff said. "We're going to retrieve those, close (them) up, take them back, put them in the shuttle cargo bay, and then we take new ones out of the cargo bay, MISSE 8, and we install them up on the truss. They'll be out there for six months to a year before they come in."

The spacewalkers then will turn their attention to preparations for topping off the ammonia coolant supply in the port six, or P6, solar array segment.

Each of the station's four sets of solar arrays are equipped with radiators that use circulating ammonia to carry away heat generated by batteries and electronics subsystems. Engineers have been monitoring a small leak in the P6 coolant system and during the crew's second spacewalk, the astronauts will top off the coolant in the P6 radiator panels. But first, Feustel and Chamitoff must hook up the jumpers to complete what amounts to a long hose running from an ammonia storage tank on the P1 truss segment all the way out to P6.

"We have to sort of connect a lot of ammonia hoses between a lot of segments including one that jumps across the rotating solar alpha rotary joint, which normally can't have a hose running across (it). It has to spin freely.

"We're going to go out and we're going to connect all these hoses and then vent them basically so that they're filled with N2, the nitrogen. We're going to vent them so that they're ready to be used for the ammonia fill on the next EVA."

After the line is vented, the segment crossing the solar alpha rotary joint -- the P3/P4 jumper -- will be disconnected so the outboard arrays can rotate as required to track the sun. Those jumpers will be reconnected during the second spacewalk when the ammonia fill will take place.

After the jumper work, Chamitoff and Feustel will install a new wireless antenna that can be used by external experiments and other payloads.

"There are experiments and payloads outside the space station (that) need to communicate to the data system and they're installing a couple of antennas and all the wiring for that to enable those pieces of equipment or experiments to communicate to internal systems," Chamitoff said.

"It's a lot of wiring. It's a little messy with long wires and it takes a while but that's going to be in the front of the space station near the shuttle. The thing that's maybe a little interesting about that is just that in order for us to do that, they have to disable some things internally. We may lose communication. We may have to wave through the window and say everything's OK, and then go down and finish the work and come back and say everything's OK. We'll see how that goes but it should be interesting."

The next day -- flight day six -- Johnson and Coleman, operating the space station's robot arm, will pull the shuttle heat shield inspection boom out of Endeavour's cargo bay and hand it off to the shuttle's arm, operated by Feustel and Vittori. The boom will be used later in the misson to inspect the shuttle's heat shield again. After the handoff, the astronauts will take a half day off to relax and catch their collective breath.

Fincke will join Feustel for the second spacewalk on flight day seven. There are two primary objectives: to fill the P6 ammonia radiator with coolant and to lubricate the port solar alpha rotary joint drive gear and bearing race.

"Building on the success of EVA 1, we hope, we're going to go out, and we have two main jobs for EVA No. 2. Both of them are for the long-duration maintenance of the International Space Station," Fincke said in a NASA interview. "Since we're the last shuttle-based EVA, we're doing things in advance for routine preventative maintenance just like with our automobiles."

Feustel will focus on making the final connections to permit six to eight pounds of ammonia to flow outboard from the P1 ammonia tank assembly to the P6 radiator, including reconnecting the P3/P4 jumper across the solar alpha rotary joint, or SARJ. It will take about 10 minutes to top off the radiator. After that, Fuestel will vent the line with nitrogen to remove any residual ammonia. Two ventings are required, one lasting 17 minutes and one about four minutes.

NASA has a history of problems with ammonia quick-disconnect fittings, and there are more than a half-dozen connections required for the P6 radiator fill. If either spacewalker gets ammonia on his suit, NASA will implement a "bake out" protocol to make sure any ammonia ice crystals sublimate away in direct sunlight, before the astronauts re-enter the space station.

"This isn't your household cleaner ammonia," Fincke said, "this is high-grade industrial ammonia so we have to be super careful not to get it on us or to spill it because it's quite dangerous if we brought it back inside. But we're going to recharge the ammonia lines. ... There's a series of jumpers that we have to go across, including the rotating solar alpha rotary joint, so we have some jumpers, a series of hoses that will fully charge our ammonia system.

"While Drew's doing that, I get to do a lubrication job, add some grease, some Braycote, to our solar alpha rotary joint," Fincke said. "We found the original design had some extra friction that we weren't expecting and it started to grind our joint. So since then, every couple years, (we've) started to add some grease on it and it rotates great. However, we won't have that ability so much in the future, so while Drew's working with the ammonia system I'll be lubricating the outside of the solar alpha rotary joint so it can last another five to ten years, no problem."

A computer animation showing Mike Fincke working with the space station's port-side solar alpha rotary joint. (Credit: NASA animation)

When the SARJ work is complete and the astronauts have verified that all tools, tethers and jumpers are inboard of the port SARJ, commands will be sent to rotate the solar arrays through 200 degrees. The 45-minute procedure will spread the grease already applied and bring the other side of the gear and race into position for lubrication.

While the array is slowly rotating, Feustel will install a lens cover on a camera used by the Canadian Special Purpose Dexterous Manipulator, or Dextre, a robot arm attachment fitting that in some cases can take the place of a spacewalking astronaut. With the lens cover in place, Feustel plans to lubricate the snares used by Dextre to hold components in place.

While Feustel is working with Dextre, Fincke will install two grapple bar stowage beams that will provide a temporary mounting point for radiator panels if replacement operations are ever required.

Finally, Fincke and Feustel will apply a final bead of grease to the SARJ race ring before re-installing six covers and heading back to the airlock.

The day after the second spacewalk, the astronauts will take another half-day off before Fincke and Feustel prepare for the mission's third spacewalk.

But this time around, the astronauts will not camp out in the Quest airlock to help remove nitrogen from their bloodstreams. Instead, they will test a new protocol known as the "in-suite light exercise" pre-breathe protocol, or ISLE for short.

Extensive testing on the ground indicates spacewalkers can remove nitrogen by simply performing light exercise the morning of the excursion while breathing pure oxygen. By avoiding the overnight campout, astronauts will not be isolated before a spacewalk and a fire alarm or other problem will not force them to open the airlock and delay a long-planned spacewalk.

"It doesn't require the overnight campout that was used for most of the previous EVAs on the last several flights," said Hassmann. "In terms of complexity, in terms of the quality of life for the crew, this ISLE protocol is a pretty significant upgrade because we don't have that point the night before where the two EVA crew has to go in the airlock, and we shut the hatch, and they're forced to spend the night in the airlock.

"With this in-suit light exercise, or ISLE, protocol, the night before an EVA looks exactly like any other night during the mission. They wake up, they don't have to stay on the portable breathing apparatus, they don't have to stay on the oxygen masks. So up until the point where they actually begin the EVA prep the morning of, it looks just like any other day.

"We think this is an improvement over the campout protocol," he said. "And of course, the main thing we're after here is crew safety. All of these crew protocols are designed to prevent the bends. Leading up to this, we put the ISLE protocol through all the standard medical reviews and tests that both the campout and exercise pre-breathe protocols have been subjected to, and everybody's comfortable it's completely safe. We think it offers some significant advantages."

The third spacewalk, on flight day nine, is devoted primarily to attaching a power and data grapple fixture -- a robot arm anchor fitting -- to the side of the Russian Zarya module, along with a video signal conditioner and associated cabling. The equipment will allow the station's robot arm to base itself on the Russian segment of the space station for maintenance work down the road.

"We've just added this EVA, and this involves installing a power and data grapple fixture, or a base, for Canadarm 2," Feustel said. "So the Canadarm space station arm has a capability of walking around the space station from end to end to do different tasks. The Russian segment doesn't really have any of those bases for the arm to walk on to.

"This is an opportunity for us to actually attach one of these base station mechanisms onto what we call the FGB or Functional Cargo Block portion of the space station to allow the arm to walk onto that position and do some tasks in areas that it wouldn't have been able to reach previous to this."

In addition to mounting the PDGF and the video signal conditioner, Fincke and Feustel also will route power and data cables from the U.S. segment of the station to the new equipment.

The day after the third spacewalk -- flight day 10 -- the astronauts will carry out an inspection of the shuttle's nose cap and wing leading edge panels to look for any signs of damage that might have occurred since launch due to impacts with space debris or micrometeoroids.

This so-called late inspection, using the shuttle's robot arm and heat shield inspection boom, normally is carried out after the shuttle undocks from the station. But Endeavour's orbiter boom sensor system, or OBSS, will be left behind aboard the station to give the lab's robot arm an extension, providing the capability to reach areas that would otherwise be inaccessible.

After the late inspection, the crew will review procedures for a fourth and final spacewalk by Fincke and Chamitoff the next day to mount the OBSS on the station's power truss. If the ISLE protocol works and no problems develop, Fincke and Chamitoff may use it again for EVA No. 4. Otherwise, they will use the normal camp out procedure.

After exiting the Quest airlock, the astronauts will set up foot restraints on the power truss and take the OBSS boom from the shuttle's robot arm, operated by Johnson, known by his nickname Box. After mounting the boom on attachment fixtures, Fincke will demate electrical connectors leading to a no-longer-needed laser scanner and heat shield inspection camera.

Then they will remove the grapple fixture on the other end of the boom that was used by the shuttle's robot arm and replace it with a fixture designed for the station arm.

"That boom will be left behind on the space station with the idea that at some point if the space station has to do some work, it would give the robotic arm more reach if it could use this boom as well," Chamitoff said. "We have left it up there before, we have the mechanisms in place to leave it up there.

"We'll be attaching that boom to the truss, locking it in place. Normally the shuttle arm grabs that boom at the end, and the station arm has a grapple fixture in the middle, but if we're going to use it on the station at some future point, you want to be able to grab it from the end. The grapple fixture at the end is not the right kind and we have to change it so it'll be kind of fun for Mike.

"Because we're kind of tearing this thing apart in a way, we're taking off that end, replacing it with a station grapple fixture, and we have to cut some wires and pull this thing off completely and while we're doing that I'll be on the station robotic arm and Box will be flying me around. That'll be an exciting task to do."

After wrapping up work to stow the OBSS, the astronauts will perform minor maintenance on the Dextre manipulator, unlatch a spare arm mounted on ELC-3 and install a protective handling fixture to the spare high-pressure oxygen tank.

The day after the final spacewalk -- flight day 12 -- the combined crews will wrap up equipment transfers, finish moving science samples from the station to the shuttle and hold a joint crew news conference. Then the two crews will bid each other farewell and close the hatches between Endeavour and the space station.

The next morning, Endeavour will undock to wrap up its final station visit.


With Johnson at the controls, the shuttle is scheduled to undock four hours after crew wakeup on flight day 13. After pulling straight away in front of the station, Johnson will kick off a one-lap fly-around, loop up over, behind, below and back in front of the lab complex.

At that point, the shuttle normally departs the area for good. But Endeavour's crew plans to test software and new sensors designed for use on the Orion capsule Lockheed Martin is designing for possible deep space exploration.

The Sensor Test for Orion Relative Navigation Risk Mitigation experiment -- STORRM -- will operate in the background during Endeavour's approach to the station on flight day three, collecting data that will allow engineers to calibrate the system.

After Endeavour's one-lap fly around after undocking, Johnson and Kelly will guide the shuttle through another looping rendezvous sequence to put the new equipment to the test.

The shuttle Endeavour, landing at the Kennedy Space Center in 2009. (Credit: NASA)
"The orbiter will undock and back away and do a full one lap fly-around like we normally do," said shuttle flight director Gary Horlacher. "We'll do the nominal sep 1 burn and the sep 2 burn will put us on the STORRM re-rendezvous trajectory. So we're going to phase out above station and behind it and STORRM will be taking data all the way out until the sensors drop lock outside 20,000 feet.

"Then we'll go ahead and do an orbit lowering burn, which is going to bring us down below the space station and get us set up for the trajectory to mimic the Orion approach to the space station. This approach is called a co-elliptic approach, so this burn down here is going to put us in a co-elliptic trajectory under the space station and then we'll be catching back up to it and do the terminal phase initiation burn, which will bring us back up towards station.

"It's designed to have us stall out about 1,000 feet below and 300 feet behind the space station," he said. "And then orbital mechanics will pull us down and away. STORRM sensors will continue to take data until the sensors drop lock. And when we get outside that range, we'll go ahead and call the docked mission complete and then we'll get our nominal water dumps accomplished and get the ship prepared to come back home."

The astronauts will pack up and test the shuttle's re-entry systems the next day, stowing gear and breaking down their computer network. Kelly and Johnson will take turns flying a shuttle flight simulator to practice landing procedures, and the crew will handle a final round of media interviews.

Landing currently is planned for flight day 15 -- Friday, May 13, assuming an April 29 liftoff. But NASA managers likely will extend the flight at least one and possibly two days to give the shuttle crew more time to help their station colleagues carry out maintenance on the station's life support system.

"We're going to lift off with a 14-day planned mission," said Mike Moses, the shuttle integration manager at the Kennedy Space Center. "We have two extension days in addition to the two weather and systems wave-off days that we keep for deorbit and landing contingencies. So we have two mission extension days this time.

"After we get docked to station, probably around flight day five or so, the mission management team ... will take a look at where we're at. The mission ops team has a really good plan where those two extra days will go in. We'll probably add those two days, taking it to a 16-day mission. But we won't do that until we get in orbit and see what we've got.

If two extension days are added, landing would slip to flight day 17, or May 15 for an April 29 launch.

And that will be the end of the line for Endeavour.

"Three out of six of us have flown on Endeavour," Kelly told reporters. "It's pretty close to my heart because it's the first space shuttle I flew on in 2001. I'm glad it's the one I'm going to fly on last, it's the baby of the fleet, it's coming up on 19 years in service, the 25th flight. Twenty five's a good round number to end on."

On April 12 -- the 30th anniversary of the first shuttle flight -- NASA Administrator Charles Bolden ended months of speculation by announcing the museums that had been chosen to display the shuttles after the final mission.

"We want to display the vehicles as realistically as possible, but the thought that it's going to be a flyable orbiter is just not true," Shannon said. "There's a lot of safety issues where you have toxic chemicals and things, and we've got to take that plumbing off and we're not going to replace it. We'll either safe it in place, if we can't safe it in place, you just remove it.

"The main engines are an extremely valuable asset, and I want to save all of our block 2 SSMEs. We have a plan to store them in a purged, safe environment along with all of the ground systems required to maintain them until we decide what to do with the next program. So what we did is, we went and really searched the facilities for excess hardware that we could build up into some main engines. So we'll have nine engines we'll put into each of the vehicles that are older technology engines, but they're real nozzles that flew, they're real combustion chambers, real pumps. And so we'll take out the really good engines we'd like to save for the next program, we'll put in rebuilt engines that we kind of scrapped together, and that is what will be displayed."

Shannon said NASA also hopes to cobble together enough spare parts to build a few stand-alone engines that can be put on display by the orbiters "so people can see how big and how complex they really are. I'm also trying to save the OMS engines, the smaller orbital maneuvering system engines on the back. Same reason, if we can use them in a future program, I think they are very valuable assets. We don't have a lot of spares on those, so those are probably going to be mocked up."

During the decommissioning phase, engineers are going to take the opportunity to inspect or remove components that are buried in the shuttle and have not been inspected since construction began decades ago. The hydraulic actuators that move the shuttle's elevons, for example, are prime candidates for removal.

"I had some pretty good debates with the ground operations team about the difficulty in going to get some of these things," Shannon said. "But from an engineering standpoint, this is a once-in-a-lifetime opportunity to go see how a reusable vehicle actually weathered this many cycles, this many times on orbit, this much time in ground processing. So we'll go get representative actuators, we're going to get main engine flow liners, things that basically you started with it, then you built the orbiter around it.

"It's very invasive to go in and get them, but I've asked the team to go in there and do that. We'll send those out to our labs. That's kind of the next legacy of the shuttle program is to give you a lot of material knowledge, a lot of design knowledge in how things work over a long period of time."

The shuttle will look the same to the public, but "we're going to put on some hardware so we can save some of the higher value hardware, we're going to safe it so that the public's not exposed to anything dangerous, and we'll remove some things the public would never see."

"To me, it's more important to get that engineering knowledge out of these vehicles than it is to have total accuracy in a museum."