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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Space Shuttle retirement | 4/6 | https://en.wikipedia.org/wiki/Space_Shuttle_retirement | reference | science, encyclopedia | 2026-05-05T13:22:34.746709+00:00 | kb-cron |
== Former planned Space Shuttle successors == There were a number of proposals for space access systems in the 1970s also, such as the Rockwell Star-raker. Star-raker was a large single-stage to orbit (SSTO) design that used both rockets and ramjet for propulsion. It was a contemporary to the Boeing Reusable Aerodynamic Space Vehicle, which was an all-rocket propulsion SSTO design. Some programs from the early 1980s were the Future Space Transportation System program and the later NASA Advanced Manned Launch System program. In the late 1980s, a planned successor to STS was called "Shuttle II", which encompassed a number of different ideas including smaller tanks over the wings and a detachable crew cabin for emergencies, and was influenced by the Challenger disaster. At one point before retirement, extension of the Space Shuttle program for an additional five years, while a replacement could be developed, was considered by the U.S. government. Some programs proposed to provide access to space after the shuttle were the Lockheed Martin X-33, VentureStar, the Orbital Space Plane Program, and Ares I launcher. For comparison to an earlier retirement, when the Saturn IB was last flown in 1975 for the Apollo-Soyuz Test Project, the Shuttle development program was already well underway. However, the Shuttle did not fly until 1981, which left a six-year gap in U.S. human spaceflight. Because of this and other reasons, in particular, higher than expected Solar activity that caused Skylab's orbit to decay faster than hoped, the U.S. space station Skylab burned up in the atmosphere. The Ares I was going to be NASA's crewed spacecraft after STS, with Congress attempting to accelerate its development so it would be ready as early as 2016 for the ISS, in addition they attempted to delay retirement of the shuttle to reduce the time gap. However, Ares I was cancelled along with the rest of Constellation in 2010. The successor to the Space Shuttle after the cancellation would be commercial crew spacecraft, such as the Dragon 2 from SpaceX which first launched crew on May 30, 2020, as the SpaceX Demo-2 mission, and the Starliner from Boeing which first launched crew on June 5, 2024, as the Boeing CFT mission, while NASA's flagship in-house crewed missions will be aboard Orion on the SLS.
=== Constellation Program ===
Following the Space Shuttle Columbia disaster, in early 2003 President George W. Bush, announced his Vision for Space Exploration which called for the completion of the American portion of the International Space Station by 2010 (due to delays this would not happen until 2011), the retirement of the Space Shuttle fleet following its completion, to return to the Moon by 2020 and one day to Mars. A new vehicle would need to be developed, it eventually was named the Orion spacecraft, a six-person variant would have serviced the ISS and a four-person variant would have traveled to the Moon. The Ares I would have launched Orion, and the Ares V heavy-lift vehicle (HLV) would have launched all other hardware. The Altair lunar lander would have landed crew and cargo onto the Moon. The Constellation program experienced many cost overruns and schedule delays, and was openly criticized by the subsequent U.S. president, Barack Obama. In February 2010, the Obama administration proposed eliminating public funds for the Constellation program and shifting greater responsibility of servicing the ISS to private companies. During a speech at the Kennedy Space Center on April 15, 2010, President Obama proposed the design selection of the new HLV that would replace the Ares-V but would not occur until 2015. The U.S. Congress drafted the NASA Authorization Act of 2010 and President Obama signed it into law on October 11 of that year. The authorization act officially cancelled the Constellation program. The development of the combination of Ares I and Orion was predicted to cost about US$50 billion. One of the issues with Ares I was the criticism of the second stage, which the post-cancellation Liberty proposal attempted to address by using a second stage from an Ariane 5. The Liberty proposal applied for but was not chosen for commercial crew. The other ongoing complaint was that it made more sense to make a man-rated version of the Atlas or Delta. The first crewed flight for Ares I was scheduled for March 2015, and one of its priorities was crew safety. One reason for the emphasis on safety was that it was envisioned in the aftermath of the Columbia disaster.
== Current and future Space Shuttle successors ==
=== Soyuz === U.S. astronauts have continued to access the ISS aboard the Russian Soyuz spacecraft. The Soyuz was chosen as the ISS lifeboat during the development of the International Space Station. The first NASA astronaut to launch on a Soyuz rocket was Norman Thagard, as part of the Shuttle-Mir program. Launching on March 14, 1995, on Soyuz TM-21, he visited the Mir however he returned to Earth on the Space Shuttle mission STS-71. The start of regular use of the Soyuz began as part of the International Space Station program, with William Shepherd launching on Soyuz TM-31 in October 2000. NASA has continued to take regular flights in the following two decades. NASA was contracted to use Soyuz seats until at least 2018. The consideration of Soyuz as a lifeboat began in the aftermath of the dissolution of the Soviet Union. Russia proposed using the Soyuz as a lifeboat for what was still Space Station Freedom in late 1991, leading to further analysis of this concept in the early 1990s. One of the milestones was in 1992, when after three months of negotiations the heads of the two Space Agencies agreed to study applications of the Soyuz spacecraft.