NASA has ordered long-lead items for a system to extend Space Shuttle Atlantis' time docked with the International Space Station, but has yet to decide whether to use the orbiter after this year and incur the additional cost of installing the equipment.
The station-to-shuttle power transfer system (SSPTS) allows the ISS to provide the orbiter with power, reducing the Shuttle's consumption of liquid hydrogen and oxygen for the fuel cell used to generate electricity. It would allow the orbiter to stay docked for up to 12 days, depending on the mission plan.
With only 13 flights left before the Shuttle fleet is retired, Atlantis' final mission is planned to be the Hu
bble Space Telescope servicing mission, STS-125, which is scheduled for installation later this year.
Space Shuttle Atlantis in orbit
"[Installing SSPTS] would give us flexibility to schedule missions on any of the three orbiters," says NASA. "If we had a flight with five spacewalks scheduled for Discovery or Endeavour that we needed to move to Atlantis for some reason, having SSPTS on Atlantis would allow us to retain all five spacewalks, and not redesign the flight to have fewer spacewalks. At this point we would only pay for the installation cost and we're still determining that figure."
NASA managers are meeting in the coming weeks to address the remaining Shuttle mission schedule beyond Endeavour's March STS-123 flight. As part of that process the agency will examine the option that adds two flights to Atlantis' schedule after STS-125.