November 18, 2009
Shuttle Delivers Spares
The Space Shuttle Atlantis arrived at the International Space Station (ISS) today (Wednesday, Nov. 18), delivering two huge carriers packed with spares for critical station systems.
The first Express Logistics Carrier (ELC-1), about the size of a small car, will be pulled from the shuttle's payload bay by the shuttle's robotic arm this afternoon. Astronauts Randolph Bresnik and Leland Melvin will "hand over" the ELC-1 from the shuttle arm to the station arm, controlled by shuttle crewmember Barry Wilmore and station crewmember Jeffrey Williams. The ELC-1 will then be "parked" on the Earth-facing side of the port (left) side of the truss.
The spares on this carrier are big heavy items such as a 600-pound control moment gyroscope, a 550-pound nitrogen tank, a 780-pound external cooling system pump, and a 1700-pound tank of ammonia. Though all these spares are weightless in freefall, they retain their mass, which means they have to be moved very slowly to keep the force (mass times acceleration) to a minimum.
The second carrier, ELC-2, will be shifted from the shuttle to the station on Saturday. The total mass of these two carriers is about 27,000 pounds, requiring the heavy-lift capability that only the space shuttle currently provides. A typical Russian Progress delivers about 5500 pounds to the station. Space X's Falcon cargo rocket, currently under development, is planned to lift about 23,000 pounds to ISS initially and up to 65,000 pounds eventually.
Spacewalkers Michael Foreman and Robert Satcher, Jr. will be camping out in the station airlock tonight in preparation for the first spacewalk of the mission Thursday. Foreman and Bresnik will be teamed up for the spacewalk on Saturday, and Satcher and Bresnik on Monday.
Atlantis is scheduled to undock next Wednesday and land at Kennedy Space Center on Friday, the day after Thanksgiving.
To the stars!
Posted by m_dyson at November 18, 2009 12:00 PM