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2008
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L'Orbiter et 4 astronautes de l'équipage suivant sont réassignés à la mission de secours. La planification et l'entraînement pour ce type de mission s'étale sur 40 jours à partir du moment ou elle est décidé. Pendant ce temps, les astronautes en orbite trouvent refuge dans la station ISS. La station est capable d'abriter son équipage principal plus celui d'un Shuttle pendant 80 jours. Les missions LON font parties d'un plan de la NASA appelé Contingency Shuttle Crew Support (CSCS) et qui a demaré à partie de STS 121 en 2006 avec STS 300.
Prior to STS-121 the plan was for the damaged shuttle to be abandoned and allowed to burn up upon reentry. STS-121 was the first shuttle mission to carry an 8.5-meter cable designed to connect the flight deck manual controls used during landing to an avionics bay in the middeck in order to allow mission controllers to attempt to land the shuttle unmanned if required. Such an unmanned landing may be considered if the vehicle suffers damage that is too severe to risk a manned reentry, but where there remains a reasonable probability of the shuttle landing intact. The preferred site for an unmanned landing would probably be Edwards Air Force Base, in California,[8] where the expanse of dry lake bed gives a large margin for error, unlike KSC where canals border the landing facility. White Sands Missile Range in New Mexico would be the likely alternate site. [1] 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 Orbiter would reenter on a trajectory such that if it should break up, it would do so with debris landing in the South Pacific Ocean.[2] To save weight, and to allow the combined crews of both shuttles to return to Earth safely, many shortcuts would have 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 be faced. If it is ever implemented, it has been predicted that such a mission would be the last flight of a Space Shuttle and thus mark the end of the Shuttle program and the halt of further ISS construction, especially if NASA fails to to recover both vehicles in spaceworthy condition. It has been stated that the Shuttle program could not be sustainably run with fewer than three Orbiters.[9] MATERIELS De nombreux équipements necessaire au missions LON ont été construit en prévision, comme trois siéges supplémentaires à installer dans le middeck Flight hardware A number of pieces of Launch on Need flight hardware have been built in preparation for a rescue mission including: * An extra three recumbent seats to be located in the aft middeck (ditch area) * 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 genies * Escape Pole mounting provisions for three additional lanyards [10]
[edit] Remote Control Orbiter The Remote Control Orbiter (RCO), also known as the Autonomous Orbiter Rapid Prototype (AORP), is a term used by NASA to describe a Shuttle that could perform entry and landing without a human crew onboard. To this end, NASA developed the RCO in-flight maintenance (IFM) cable. The cable is approximately 28 feet (8.5 m) long, weighs over 5 lb (2.3 kg), and has 16 connectors.[11] The purpose of the RCO IFM cable is to provide an electrical signal connection between the Ground Command Interface Logic (GCIL) and the flight deck panel switches. With this system, signals could be sent from the Mission Control Center to the unmanned Shuttle to control the following systems: * Auxiliary Power Unit (APU) start and run * Air Data Probe (ADP) deployment * Main Landing Gear (MLG) 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 stowage during the mission. The cable will remain aboard the ISS until the end of the Shuttle program at which time it will be brought back to Earth on the final Shuttle flight. The prime landing site for an RCO orbiter would be Vandenberg Air Force Base in California[12]. 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. [edit] Shuttle backup plan STS-300 lower deck seat layout to accommodate additional crew STS-300 lower deck seat layout to accommodate additional crew Barring retirement of Atlantis (OV-104), which as of 2008 is scheduled in September 2008; NASA's remaining two operational vehicles, Discovery (OV-103) and Endeavour (OV-105), will still have to back each other up should the need for an STS-3xx mission arise. After Atlantis completes STS-125 and begins its "near operational condition" status in fall of 2008, it too will carry its share of Launch-on-Need duty. Presently it is a planned backup rescue orbiter for missions STS-120 and STS-124. Additionally, Atlantis will also be used as a parts vehicle for the other two operational shuttles when its flight ready status is terminated in the fall of 2008.
Pre-ISS eraThe STS-3xx missions were developed in the aftermath of the Space Shuttle Columbia disaster. However, NASA spent some effort researching rescue options even before the disaster. Before the ISS was launched, or in the event of the shuttle being unable to reach the station, shuttle crews would have had to transfer directly between shuttles. The orbiters would have been unable to dock, so while they used their RMS arms to grapple each other, the crew would have made an EVA between the shuttles. This would have been carried out using the two EVA-designated mission specialists wearing the Shuttle/ISS Extravehicular Mobility Unit (EMU) spacesuits, while the remaining crew would have been sealed up in pressurized Personal Rescue Enclosure and carried over either by hand, or using a pulley system (akin to that of a clothesline pulley) like that employed in the Apollo program for lifting samples from the Moon's surface into the Lunar Module. [edit] Timeline * FD-10 A decision on the requirement for Contingency Shuttle Crew Support (CSCS) 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 (ISS) 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 Edwards Air Force Base under remote control from Houston. (Prior to STS-121, the payload bay doors would have been left open to promote vehicle breakup.) * 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.[2] * FD-45->47 The rescue flight catches up with the ISS, conducting heat shield inspections en-route. * FD-47 The rescue flight will dock 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 CELSS O2 exhaustion in event Progress unable to perform resupply function. The above timeline is presented with respect to the flight day (FD) of the mission to be rescued. [edit] STS-125 rescue Main article: STS-400 STS-125 is a Hubble Space Telescope servicing mission. Since the Hubble telescope is in a different orbit to the International Space Station, there is no option for a shuttle crew to use the ISS as a safe haven, so NASA developed a plan to conduct a shuttle-to-shuttle rescue mission, similar to proposed rescue missions for pre-ISS flights.[13][14] This rescue mission, designated STS-400, would be launched only ten days after call up, if necessary, as the maximum time the crew can remain on the damaged shuttle is 23 days. For this mission, the rescue shuttle (currently planned to be Endeavour) will be rolled to its launch pad about two weeks before the STS-125 shuttle, creating a rare scenario of two shuttles being on the launch pads at the same time. The mission would probably follow a similar procedure to the pre-ISS era plan, as outlined above. Three different concept mission plans have been evaluated. The first would be to use a shuttle-to-shuttle docking, where the rescue shuttle docks with the damaged shuttle, by flying upside down and backwards, relative to the damaged shuttle.[14] It is unclear whether this would be practical, as the forward structure of either orbiter could collide with the payload bay of the other, resulting in damage to both orbiters. The second option that was evaluated, would be for the rescue orbiter to rendezvous with the damaged orbiter, and perform station-keeping while using its Remote Manipulator System (RMS) to transfer crew from the damaged orbiter. This mission plan would result in heavy fuel consumption. The third concept would be for the damaged orbiter to grapple the rescue orbiter using its RMS, eliminating the need for station-keeping. The rescue orbiter would then transfer crew using its RMS, as in the second option, and would be more fuel efficient than the station-keeping option.[14] The concept that was eventually decided upon was a modified version of ideas. The rescue orbiter would use its RMS to grapple the end of the damaged orbiter's RMS.[15] During the first EVA, a tether would be set up between the two shuttles' airlocks. Both crew and Launch and Entry Suit (LES) spacesuits would be transferred from the damaged orbiter to the rescue orbiter along the tether, while EMU spacesuits will be transferred back to the damaged orbiter. Over the course of three spacewalks, all crew and LES will be transferred to the rescue orbiter. Three EMUs will be transferred to the rescue orbiter, and three will remain aboard the damaged orbiter, due to lack of space aboard the rescue orbiter.[15] The tether will be retracted during the third spacewalk. The rescue orbiter would release the RMS attachment while the spacewalkers are still in vacuum conditions, so they could manually release the attachment if the RMS system should malfunction.[15] The rescue orbiter would then land normally, and the damaged orbiter would either be disposed of through a destructive re-entry over the Pacific, or if the damage allows, landed at Vandenberg or White Sands using the RCO (AORP) system.
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