The Space Shuttle, which has been used since 1982, is ready to be replaced. The fleet of Space Shuttles has completed over 130 missions and made numerous discoveries; however, the shuttles are nearing the end of their lifespan. They are scheduled to be decommissioned in 2010 or soon after. There are a number of replacements that have been proposed for the Space Shuttle in both the public and private sectors.
Although NASA had plans to retire the Space Shuttle, for many years they proposed no definite alternative. In 2004 though, the government announced its proposal for the Space Shuttle’s replacement. The major design that NASA is working on is the Orion, which is being built by Lockheed Martin for the government. The creation of the Orion was partly influenced by the Space Shuttle Columbia disaster. Originally, NASA hoped to have Orion ready by 2013, but that date has already been pushed back a year. Congress has set 2015 as the time when the spacecraft should be ready for its first flight.
The Orion is designed to hold between four and six crew members; the Space Shuttles held as many as seven. The Orion consists of the launch abort system, the crew module, the service module, and the spacecraft adapter. The Orion would be launched using the Ares rocket, which was named the 2009 invention of the year by Time magazine. NASA is also developing a larger version of the Ares to carry supplies.
The Orion and Ares are both being developed under NASA’s Constellation program. The plan was that these spacecraft would be used to take astronauts back to the Moon and eventually to Mars. The first missions were going to be trips to resupply the International Space Station. Recently however, there have been proposals to cut the Constellation program due to its enormous cost. If the government does end up scrapping the Constellation program though, it will be left with no replacement for the Space Shuttle in the near future. This is a serious matter because the Space Shuttles are already considered beyond their lifespan by many.
Advances are also being made in the private sector. In 2004, the first non-government spacecraft, SpaceShipOne, reached space and won the Ansari X Prize. The company, Scaled Compositions, also produced a SpaceShipTwo, which was unveiled to the public recently. The development of these spacecraft has fueled the belief that space tourism is in the near future.
Universe Today has articles on first look at the Orion and Ares Orion.
Astronomy Cast has an episode on the US Space Shuttle.