Expendable launch system

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A Delta II ELV launching the Dawn spacecraft from CCAFS SLC-17

An expendable launch system is a launch system that uses an expendable launch vehicle (ELV) to carry a payload into space. The vehicles used in expendable launch systems are designed to be used only once (i.e. they are "expended" during a single flight), and their components are not recovered for re-use after launch. The vehicle typically consists of several rocket stages, discarded one by one as the vehicle gains altitude and speed.

Design rationale[edit]

The ELV design differs from that of reusable launch systems, where the vehicle is launched and recovered more than once. Reuse might seem to make systems like the Space Shuttle more cost effective than ELVs, but in practice launches using ELVs have been less expensive than Shuttle launches. (See Space Shuttle Program and Criticism of the Space Shuttle program for discussion of Space Shuttle economics). Most satellites are currently launched using expendable launchers; they are perceived as having a low risk of mission failure, a short time to launch and a relatively low cost.[according to whom?]

History[edit]

Many orbital expendable launchers are derivatives of 1950s-era ballistic missiles. Many[who?] see this as unfortunate because cost was not a major consideration in their design. A prime example of this is the Titan IV, the costliest per-unit launch vehicle in history (following the Space Shuttle).

On the other hand, a reusable launcher such as the Shuttle requires a heavier structure and a recovery system (wings, thermal protection system, wheels, etc.) that reduce payload capacity. The Shuttle additionally carried a crew (though not inherent to a reusable system) whose weight, supplies and life support systems further decrease payload capacity.

The Space Shuttle was a major national asset, and its high cost (far more than a single expendable launch vehicle) and presence of a crew require stringent "man rated" flight safety precautions that increased launch and payload costs. Only five orbiters were built, and the loss of two (Challenger and Columbia) significantly impacted the capacity and viability of the Shuttle program. Each loss also resulted in an extended hiatus in Shuttle flights compared to that following most expendable launch failures, each of which impacted only that model of launcher.

For these reasons it is generally[according to whom?] agreed that the Space Shuttle did not deliver on its original promise to reduce the costs of constructing and launching payloads into orbit. The Shuttle was originally intended to replace expendable launchers in the launching of satellites, but after the loss of Challenger the Shuttle was reserved for previously planned missions and those requiring a crew.

Spacecraft launched by the Shuttle included several TDRSS communications relays heavily used by the Shuttle program itself, a series of commercial communication satellites, and the interplanetary probes Magellan, Galileo and Ulysses. Several classified military payloads were also carried.

Development[edit]

European sponsorship[edit]

Main article: Arianespace

On March 26, 1980, the European Space Agency and the Centre National d'Etudes Spatiales (CNES) created Arianespace, the world's first commercial space transportation company. Arianespace produces, operates and markets the Ariane launcher family. By 1995 Arianespace lofted its 100th satellite and by 1997 the Ariane rocket had its 100th launch.[1] Arianespace's 23 shareholders represent scientific, technical, financial and political entities from 10 different European countries. The major shareholder is the CNES, with 34.68% of capital.[2]

American deregulation[edit]

Main article: Private spaceflight

From the beginning of the Shuttle program until the Challenger disaster in 1986, it was the policy of the United States that NASA be the public-sector provider of U.S. launch capacity to the world market.[3] Initially NASA subsidized satellite launches with the intention of eventually pricing Shuttle service for the commercial market at long-run marginal cost.[citation needed]

On October 30, 1984, United States President Ronald Reagan signed into law the Commercial Space Launch Act.[4] This enabled an American industry of private operators of expendable launch systems. Prior to the signing of this law, all commercial satellite launches in the United States were limited to NASA's Space Shuttle.[citation needed]

On November 5, 1990, United States President George H. W. Bush signed into law the Launch Services Purchase Act.[5] The Act, in a complete reversal of the earlier Space Shuttle monopoly, ordered NASA to purchase launch services for its primary payloads from commercial providers whenever such services are required in the course of its activities.

Russian privatization[edit]

The Russian government sold part of its stake in RSC Energia to private investors in 1994. Energia together with Khrunichev constituted most of the Russian manned space program. In 1997, the Russian government sold off enough of its share to lose the majority position.

American subsidization[edit]

In 1996 the United States government selected Lockheed Martin and Boeing to each develop Evolved Expendable Launch Vehicles (EELV) to compete for launch contracts and provide assured access to space. The government's acquisition strategy relied on the strong commercial viability of both vehicles to lower unit costs. This anticipated market demand did not materialize, but both the Delta IV and Atlas V EELVs remain in active service.

Launch alliances[edit]

Since 1995 Khrunichev's Proton rocket is marketed through International Launch Services while the Soyuz rocket is marketed via Starsem. Energia builds the Soyuz rocket and owns part of the Sea Launch project which flies the Ukrainian Zenit rocket.

In 2003 Arianespace joined with Boeing Launch Services and Mitsubishi Heavy Industries to create the Launch Services Alliance. In 2005, continued weak commercial demand for EELV launches drove Lockheed Martin and Boeing to propose a joint venture called the United Launch Alliance to monopolize the United States government launch market.[6]

Today many commercial space transportation companies offer launch services to satellite companies and government space organizations around the world. In 2005 there were 18 total commercial launches and 37 non-commercial launches.[7] Russia flew 44% of commercial orbital launches, while Europe had 28% and the United States had 6%.

See also[edit]

References[edit]

  1. ^ Arianespace
  2. ^ Arianespace
  3. ^ http://www.cbo.gov/ftpdocs/59xx/doc5935/doc24c-Entire.pdf
  4. ^ Statement on signing the Commercial Space Launch Act
  5. ^ Space Frontier Foundation — Advancing Newspace, championing ideas for opening the space frontier to human settlement as rapidly as possible
  6. ^ Boeing, Lockheed Martin to Form Launch Services Joint Venture | SpaceRef - Your Space Reference
  7. ^ Office of Commercial Space Transportation

External links[edit]