Expendable launch system

An expendable launch system or expendable launch vehicle, ELV, is a single-use launch vehicle usually used to launch a payload into space. This is in opposition to a reusable launch system where a single launch vehicle is launched more than once.

Expendable launch systems typically consist of stages which are discarded one by one, in order not to have to carry and accelerate parts that are no longer needed, see staging and multistage rocket, as opposed to the as-yet theoretical single stage to orbit system. However, there is no reason in principle why an expendable single stage to orbit system would be impossible; it is just generally more efficient to use staging when the system is not meant to be recovered intact.

Most orbital expendable launchers are derivatives of 1950s-era ballistic missiles. Since the entire vehicle is discarded after launch, this may seem like an expensive launch method, but in practice they are cheaper than the one currently-existing partly reusable launch vehicle (the space shuttle -- see the shuttle article for a discussion of its economics). Most satellites are 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. The Magellan probe was the first planetary spacecraft launched by a space shuttle.

Many see it as unfortunate that most "modern" orbital expendables are derived from ballistic missiles, as these missiles were built to Cold War specs and with Cold War budgets, and argue that this makes for horrendously expensive launch vehicles. A prime example of this is the Titan IV, probably the costliest per-unit launch vehicle in history (perhaps following the Space Shuttle).

On the other hand, reusable launchers have to be built more robustly and thus carry extra dry weight to orbit, and require recovery systems, and thus everything else being equal (to a similarly constructed expendable), would have a very much smaller payload. Reusable launchers would thus not necessarily be enormously cheaper.

Expendable orbital launchers

Currently in use

* Ariane V
* Atlas V
* Cosmos-3M
* Delta 2
* Delta 4
* Dnipro
* H-2A rocket
* Long March rocket
* Pegasus rocket
* Polar Satellite Launch Vehicle
* Geosynchronous Satellite Launch Vehicle
* Proton rocket
* Rockot
* Sea Launch
* Soyuz launch vehicle
* Tsyklon
* Zenit

Planned

*Geosynchronous Satellite Launch Vehicle MK-III
*Angara rocket
*Shuttle Derived Launch Vehicle
*Soyuz/ST
*Vega
*Falcon 1
*Falcon 5
*Falcon 9

Historical

*Ariane 1
*Ariane 2 and Ariane 3
*Ariane 4
*Atlas (rocket)
*Atlas II
*Delta III
*Diamant
*Energiya
*Europa rocket
*N1 rocket
*R-7 rocket
*Saturn I
*Saturn IB
*Saturn V
*Thor
*Titan I (see Titan rocket)
*Titan II
*Titan III
*Titan IV
*Voskhod rocket
*Vostok rocket

Development

European Sponsorship

On March 26, 1980, the European Space Agency 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.[2]

American Deregulation

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 povider of US Commercial Orbital Transportation Serviceslaunch 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.

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.

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 Privitization

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 their share to lose the majority position.

American Subsidization

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. Since this anticipated market demand did not materialize for the, Boeing pulled the Delta IV EELV from commercial service in 2003. The Lockheed Martin Atlas V EELV has had five commercial launches through the end of 2005.

Launch Alliances

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].

See also

list of rockets, space transport, spacecraft propulsion and history of commercial space transportation