STS-3xx


Space Shuttle missions designated STS-3xx were rescue missions which would have been mounted to rescue the crew of a Space Shuttle if their vehicle was damaged and deemed unable to make a successful reentry. Such a mission would have been flown if Mission Control determined that the heat shielding tiles and reinforced carbon-carbon panels of a currently flying orbiter were damaged beyond the repair capabilities of the available on-orbit repair methods. These missions were also referred to as Launch on Demand and Contingency Shuttle Crew Support. The program was initiated following loss of Space Shuttle Columbia in 2003. No mission of this type was launched before the Space Shuttle program ended in 2011.

Procedure

The orbiter and four of the crew which were scheduled to fly the next planned mission would be retasked to the rescue mission. The planning and training processes for a rescue flight would have allowed NASA to launch the mission within a period of 40 days of its being called up. During that time, the damaged shuttle's crew would have to take refuge on the International Space Station. The ISS was able to support both crews for around 80 days, with oxygen supply being the limiting factor. Within NASA, this plan for maintaining the shuttle crew at the ISS was known as Contingency Shuttle Crew Support operations. Up to STS-121 all rescue missions were to be designated STS-300.
In the case of an abort to orbit, where the shuttle could have been unable to reach the ISS orbit and the thermal protection system inspections suggested that the shuttle could not have returned to Earth safely, the ISS may have been capable of descending to meet the shuttle. Such a procedure was known as a joint underspeed recovery.
FlightRescue flight
STS-114 STS-300
STS-121 STS-300
STS-115 STS-301
STS-116 STS-317
STS-117 STS-318
STS-118 STS-322
STS-120 STS-320
STS-122 STS-323
STS-123 STS-324
STS-124 STS-326
STS-125 STS-400
STS-134 STS-335

* – originally scheduled to be Endeavour, changed to Discovery for contamination issues.
To save weight, and to allow the combined crews of both shuttles to return to Earth safely, many shortcuts would have had to be made, and the risks of launching another orbiter without resolving the failure which caused the previous orbiter to become disabled would have to have been faced.

Flight hardware

A number of pieces of Launch on Need flight hardware were built in preparation for a rescue mission including:
  • An extra three recumbent seats to be located in the aft middeck
  • Two handholds located on the starboard wall of the ditch area
  • Individual Cooling Units mounting provisions
  • Seat 5 modification to properly secure in a recumbent position
  • Mounting provisions for four additional Sky Genie egress devices
  • Escape Pole mounting provisions for three additional lanyards

    Remote Control Orbiter

The Remote Control Orbiter, also known as the Autonomous Orbiter Rapid Prototype, was a term used by NASA to describe a shuttle that could perform entry and landing without a human crew on board via remote control. NASA developed the RCO in-flight maintenance cable to extend existing auto-land capabilities of the shuttle to allow remaining tasks to be completed from the ground. The purpose of the RCO IFM cable was to provide an electrical signal connection between the Ground Command Interface Logic and the flight deck panel switches. The cable is approximately long, weighs over, and has 16 connectors. With this system, signals could be sent from the Mission Control Center to the unmanned shuttle to control the following systems:
  • Auxiliary Power Unit start and run
  • Air Data Probe deployment
  • Main Landing Gear arming and deployment
  • Drag chute arming and deployment
  • Fuel cell reactant valve closure
The RCO IFM cable first flew aboard STS-121 and was transferred to the ISS for storage during the mission. The cable remained aboard the ISS until the end of the Shuttle program. Prior to STS-121 the plan was for the damaged shuttle to be abandoned and allowed to burn up on reentry. The prime landing site for an RCO orbiter would be Vandenberg Air Force Base in California. Edwards Air Force Base, a site already used to support shuttle landings, was the prime RCO landing site for the first missions carrying the equipment; however Vandenberg was later selected as the prime site as it is nearer the coast, and the shuttle can be ditched in the Pacific should a problem develop that would make landing dangerous. White Sands Missile Range in New Mexico is a likely alternate site. A major consideration in determining the landing site would be the desire to perform a high-risk re-entry far away from populated areas. The flight resource book, and flight rules in force during STS-121 suggest that the damaged shuttle would reenter on a trajectory such that if it should break up, it would do so with debris landing in the South Pacific Ocean.
The Soviet Buran shuttle was also remotely controlled during its entire maiden flight without a crew aboard. Landing was carried out by an onboard, automatic system.
As of March 2011 the Boeing X-37 extended duration robotic spaceplane has demonstrated autonomous orbital flight, reentry and landing. The X-37 was originally intended for launch from the Shuttle payload bay, but following the Columbia disaster, it was launched in a shrouded configuration on an Atlas V.

Sample timeline

Had a LON mission been required, a timeline would have been developed similar to the following:
  • FD-10 A decision on the requirement for Contingency Shuttle Crew Support is expected by flight day 10 of a nominal mission.
  • FD-10 Shortly after the need for CSCS operations a group C powerdown of the shuttle will take place.
  • FD-11→21 During flight days 11–21 of the mission the shuttle will remain docked to the international space station with the hatch open. Various items will be transferred between the shuttle and ISS.
  • FD-21 Hatch closure will be conducted from the ISS side. The shuttle crew remains on the ISS, leaving the shuttle unmanned
  • FD-21 Deorbit burn – burn occurs four hours after separation. Orbiter lands at Vandenberg Air Force Base under remote control from Houston.
  • FD-45 Launch of rescue flight. 35 days from call-up to launch for the rescue flight is a best estimate of the minimum time it will take before a rescue flight is launched.
  • FD-45→47 The rescue flight catches up with the ISS, conducting heat shield inspections en route.
  • FD-47 The rescue flight docks with the station, on day three of its mission.
  • FD-48 Shuttle crew enters the rescue orbiter. Vehicle with a crew complement of 11 undocks from ISS.
  • FD-49 Rescue orbiter re-enters atmosphere over Indian or Pacific Ocean for landing at either Kennedy Space Center or Edwards Air Force Base. A Russian Progress resupply spacecraft is launched at later date to resupply ISS crew. ISS precautionary de-crew preparations begin.
  • FD-58 De-crew ISS due to ECLSS O2 exhaustion in event Progress unable to perform resupply function.

    STS-125 rescue plan

STS-400 was the Space Shuttle contingency support flight that would have been launched using if a major problem occurred on during STS-125, the final Hubble Space Telescope servicing mission.
Due to the much lower orbital inclination of the HST compared to the ISS, the shuttle crew would have been unable to use the International Space Station as a "safe haven", and NASA would not have been able to follow the usual plan of recovering the crew with another shuttle at a later date. Instead, NASA developed a plan to conduct a shuttle-to-shuttle rescue mission, similar to proposed rescue missions for pre-ISS flights. The rescue mission would have been launched only three days after call-up and as early as seven days after the launch of STS-125, since the crew of Atlantis would only have about three weeks of consumables after launch.
The mission was first rolled out in September 2008 to Launch Complex 39B two weeks after the STS-125 shuttle was rolled out to Launch Complex 39A, creating a rare scenario in which two shuttles were on launch pads at the same time. In October 2008, however, STS-125 was delayed and rolled back to the VAB.
Initially, STS-125 was retargeted for no earlier than February 2009. This changed the STS-400 vehicle from Endeavour to Discovery. The mission was redesignated STS-401 due to the swap from Endeavour to Discovery. STS-125 was then delayed further, allowing Discovery mission STS-119 to fly beforehand. This resulted in the rescue mission reverting to Endeavour, and the STS-400 designation being reinstated. In January, 2009, it was announced that NASA was evaluating conducting both launches from Complex 39A in order to avoid further delays to Ares I-X, which, at the time, was scheduled for launch from LC-39B in the September 2009 timeframe. It was planned that after the STS-125 mission in October 2008, Launch Complex 39B would undergo the conversion for use in Project Constellation for the Ares I-X rocket. Several of the members on the NASA mission management team said at the time that single-pad operations were possible, but the decision was made to use both pads.

Crew

The crew assigned to this mission was a subset of the STS-126 crew: