During space shuttle Discovery's final spaceflight, the STS-133 crew members will take important spare parts to the International Space Station along with the Express Logistics Carrier-4.Steve Bowen replaced Tim Kopra as Mission Specialist 2 following a bicycle injury on Jan. 15 that prohibited Kopra from supporting the launch window. Bowen last flew on Atlantis in May 2010 as part of the STS-132 crew. Flying on the STS-133 mission will make Bowen the first astronaut ever to fly on consecutive missions.
STS-134 Update:Astronaut Rick Sturckow will serve as a backup commander for the STS-134 space shuttle mission to facilitate continued training for the crew and support teams during STS-134 Commander Mark Kelly's absence. Kelly's wife, Congresswoman Gabrielle Giffords, was critically wounded in a shooting on Jan. 8 in Tucson, Ariz. Kelly remains commander of the mission, which is targeted for launch on April 19 from NASA's Kennedy Space Center in Florida.STS-135 Update:The Space Shuttle Program baselined the STS-135 mission for a target launch date of June 28 at 3:48 p.m. EDT. It is NASA’s intent to fly the mission with orbiter Atlantis carrying the Raffaello multipurpose logistics module to deliver supplies, logistics and spare parts to the International Space Station. The mission also will fly a system to investigate the potential for robotically refueling existing spacecraft and return a failed ammonia pump module to help NASA better understand the failure mechanism and improve pump designs for future systems.In late December, the agency’s Space Operations Mission Directorate requested the shuttle and International Space Station programs take the necessary steps to maintain the capability to fly Atlantis on the STS-135 mission. The Authorization Act of 2010 directs NASA to conduct the mission, and baselining the flight enables the program to begin preparations for the mission with a target launch date of June 28. The mission would be the 135th and final space shuttle flight.
Space shuttle Discovery's external fuel tank has taken on a bit of a starring role for the STS-133 mission because of the extra work needed to handle the unexpected challenges presented by the tank's stringers.
Technicians have been working on the stringers as the shuttle stands inside the Vehicle Assembly Building. Some of the 108 stringers, which are support beams that make up the corrugated intertank portion of the external tank, developed small cracks during fueling for a Nov. 5, 2010, launch attempt. Examinations performed following a fueling test revealed cracks on other stringers.
In considering the challenges posed by the stringers after a few cracks were discovered, NASA fans and the general public found an appetite for more information about the largest single component of a space shuttle "stack."
As part of NASA's continuing social media interaction, Facebook users were given the chance to ask Kennedy's external tank expert about the modifications and the one-of-a-kind role the tank plays. Kennedy's Facebook page has drawn about 60,000 friends, with some 130,000 following the center on Twitter.
Alicia Mendoza is NASA's External Tank and Solid Rocket Booster vehicle manager at Kennedy and in between preparing the tank for Discovery's targeted launch on Feb. 24, she discussed some of the things that went into designing the tank, why it looks the way it does and why it is not recovered for re-use the way the rest of the stack is.
To save time, the two dozen questions posted to Kennedy's Facebook page were trimmed to six that covered the broadest areas. First, a few basics about the tank:
At 15 stories tall and sporting an outer shell of dark orange insulation but with no engines of its own, the tank serves the shuttle's three main engines. It is actually two tanks on top of each other, with a support ring -- including the stringers -- holding them together. The tank holds about 535,000 gallons of liquid hydrogen and liquid oxygen. Both propellants are cryogenic, which means they are super-cold. The oxygen is chilled and pressurized to minus 297 degrees F in its liquid form and the liquid hydrogen buries the temperature needle to minus 423 degrees F.
A gallon of liquid oxygen weighs about 8.5 pounds while the hydrogen is much lighter, even in liquid form, at about half a pound per gallon. But even though the chemicals may not sound heavy by the gallon, the three main engines use so much propellant that carrying it all into orbit would make an impractically large and heavy orbiter.
Therefore, NASA designed the tank to be jettisoned just as the shuttle makes it into orbit. The tank descends through the atmosphere where some of it burns up and the rest crumples and falls harmlessly into the Indian Ocean.
View This Site: Chicago Movers
