After being unloaded and checked out in space, the solid rocket is used to boost the satellite into the higher orbit. For missions requiring higher orbits than the orbiter's maximum altitude of about 500 miles (805 kilometers), a small solid rocket stage is attached to the satellites carried aboard. Specialists can repair damaged satellites already in orbit, or, if necessary, return the satellites to Earth for a major overhaul. Fully equipped laboratories, where experimenters work in a shirt-sleeve environment, can also be accommodated. Multiple payloads (up to five satellites) may be carried in the cargo bay. The orbiter's cargo bay measures 60 feet (18 meters) by 15 feet (5 meters) and carries up to about 55,000 pounds (24,948 kilograms) of payload, but because of constraints imposed should a mission have to be aborted and the orbiter return to Earth still carrying its cargo, the maximum payload capability is capped at about 50,000 pounds (22,680 kilograms). For rescue missions, the orbiter's cabin holds as many as 10 persons this means that an orbiter with a basic three-man crew can rescue all occupants of a disabled orbiter. The others can be payload specialists, usually technicians, engineers or scientists, who make observations and conduct experiments. On a standard mission, it carries up to seven crew members, only three of whom need be NASA astronauts. The Shuttle concept represents a whole new way of space flight. Orbiters are designed to fly up to 100 missions, solid rocket casings for 20 or more missions. Then the orbiter is refurbished, assembled with refurbished boosters and a new external tank and checked out for a new mission. It then re-enters the atmosphere, and like an enormous glider, makes an unpowered landing on a runway. The 122-foot (37-meter) long orbiter, about the size of a DC-9 jetliner, continues on its Earth-orbital mission for a period of three to 10 days. The tank is jettisoned over a remote part of the ocean just before the orbiter enters orbit. Instead, the design incorporates a large external tank, divided to hold both the liquid hydrogen and the liquid oxygen-a total of more than 1,577,000 pounds (715,300 kilograms) of propellants. To save space and weight on the orbiter, the tanks for the propellants which power its engines are not part of its fuselage. The casings are then towed back to the launch area for refurbishment and reuse. Specially equipped ships in the recovery area retrieve the floating casings and parachutes. At that time, the booster casings separate from the orbiter and fall into the sea, their descent being slowed by parachutes. The propellant in the two boosters burns out about 29 miles (47 kilometers) above Earth. The boosters burn in unison with the orbiter's three main engines, providing the primary thrust to get the Shuttle off the ground. The design for the new Space Shuttle vehicle called for three attached main elements: an obiter, which carries astronauts and payloads into orbit an external propellant tank two unmanned solid rocket boosters. Shuttle missions, agreed with this judgment. Air Force, which had been actively involved with Shuttle planning and which would also participate in In addition, studies indicated a reusable Space Shuttle would require the least capital risk per flight, offer the lowest technical risk in development and provide the highest rate of return on the government's investment. Moreover, spacecraft built to fly aboard a Shuttle vehicle could be designed with more emphasis an their mission capabilities, and less emphasis on their ability to withstand the rigors of conventional rocket launches. It would be reusable for up to 100 or more missions. Among the options was the concept of a reusable Space Shuttle, which offered major advantages over conventional rocket systems. 15, 1969, a Space Task Group appointed by President Nixon recommended broad outlines for the next 10 years of space exploration. As Apollo moved into high gear, NASA began to look at the directions space programs of the future might take.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |