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Proton (Прото́н) (formal designation: UR-500) is an expendable launch system used for both commercial and Russian government space launches. The first Proton rocket was launched in 1965 and the launch system is still in use as of 2012, which makes it one of the most successful heavy boosters in the history of spaceflight. All Protons are built at the Khrunichev plant in Moscow, and then transported for launch to the Baikonur Cosmodrome, where they are brought to the launch pad horizontally and then raised into vertical position for launch.
Like many Soviet boosters, the names of recurring payloads became associated with their launchers. Thus the moniker "Proton" originates from a series of large scientific Proton satellites, which were among the rocket's first payloads. It is also known as the D-1/D-1e or SL-12/SL-13.
Launch capacity to low Earth orbit is about Template:Convert/t. Geostationary transfer capacity is about Template:Convert/-. Commercial launches are marketed by International Launch Services (ILS). In a typical launch of a commercial communications satellite destined for geostationary orbit, a Proton M/Briz-M can place a spacecraft with mass at separation of includeonly>၄၁၄၀ kilograms (includeonly>၉၁၀၀ lb) into an orbit with an apogee of Template:Convert/km, a perigee of Template:Convert/km and an inclination of 19.7°.
Proton initially started life as a "super ICBM." It was designed to launch a 100-megaton (or larger) nuclear warhead over a distance of 13,000 km. It was hugely oversized for an ICBM, and was never deployed in such a capacity. It was eventually utilized as a space launch vehicle. It was the brainchild of Vladimir Chelomei's design bureau as a foil to Sergei Korolev's N1 booster with the specific intent of sending a two-man Zond craft around the Moon. With the termination of the Saturn V program, Proton became the largest expendable launch system in service until the Energia rocket first flew in 1987 and the U.S. Titan IV in 1989.
Between the 1965 first flight and 1970, the Proton experienced dozens of failures. However, once perfected it became one of the most reliable heavy launch vehicles. With a total of about 335 launches, it has an 88% success rate.
Proton launched the unmanned Soviet circumlunar flights, and was intended to have launched the first Soviet circumlunar spaceflights, before the United States flew the Apollo 8 mission. Proton launched the Salyut space stations, the Mir core segment and expansion modules, and both the Zarya and Zvezda modules of the ISS. It also launched many probes to the Moon, Mars, Venus, and even Halley's Comet (using the 4-stage D-1e version).
Proton also launches commercial satellites, most of them being managed by International Launch Services. The first ILS Proton launch was on 9 April 1996 with the launch of the SES Astra 1F communications satellite.
Since 1994, Proton has earned $4.3 billion for the Russian space industry, and by 2011 this figure is expected to rise to $6 billion.
The (GRAU index) 8K82K version is now usually called "Proton K". It is fuelled by unsymmetrical dimethyl hydrazine and nitrogen tetroxide. These are hypergolic fuels which burn on contact, avoiding the need for an ignition system, and can be stored at ambient temperatures. This avoids the need for components that are tolerant of low temperatures, and allows the rocket to sit on the pad indefinitely (other launchers with such capability include the U.S. Titan II, Titan III, and Titan IV, the Chinese Long March 2 rocket family and Long March 4 rocket family, the Soviet/Ukrainian Tsyklon launchers, the Soviet/Russian Kosmos-3 and Kosmos-3M launchers and the European Ariane 1 to Ariane 4 launchers). In contrast, cryogenic fuels need periodic topping-up of propellants as they boil off.
The fourth stage has come in multiple variants, depending on the mission. The simplest, Blok D, was used for interplanetary missions. Blok D had no guidance module, depending on the probe to control flight. Three different Blok DM versions (DM, DM2, and DM-2M) were for high Earth orbits. (Low-Earth orbits often skipped a fourth stage entirely, hence the third stage's self-contained guidance capability.) The Blok D/DM were unusual in that the fuel was stored in a toroidal tank, around the engine and behind the oxidizer tank.
The latest version is the Proton M, which can launch Template:Convert/- into geostationary orbit or Template:Convert/t into a geostationary transfer orbit. It can place up to Template:Convert/t in low Earth orbit with a 51.6-degree inclination, the orbit of the International Space Station (ISS).
The Proton M's improvements include modifications to the lower stages to reduce structural mass, increase thrust, and fully utilize propellants. Generally a Briz-M (ရုရှား: Бриз meaning Breeze) storable propellant upper stage is used instead of the Block D or Block DM stage, eliminating the need for multiple fuel supplies and oxygen top-off due to boiling; however, the Proton-M has also flown with a Block-DM upper stage. Efforts were also made to reduce dependency on foreign (usually Ukrainian) component suppliers.
Proton launch vehicles and Briz-M Upper Stages are designed and built by Khrunichev State Research and Production Space Center (Khrunichev) in Moscow, the majority owner of International Launch Services (ILS). The Center is home to all engineering, assembly and test functions of the Proton production. And now, with the recent consolidation of the Russian space enterprises, Khrunichev has direct oversight and control of up to 70% of all Proton manufacturing from suppliers to manufacturers. The consolidation directly supports Khrunichev’s ongoing efforts for vertical integration of Proton production.
The most recent enhanced Proton, the Phase III Proton-M/Briz-M launch vehicle, was flight proven on the Russian Federal dual mission of Express AM-44 and Express MD-1 in February 2009 and performed its first commercial launch in March 2010 with the Echostar XIV satellite. The Proton-M/Briz-M phase III configuration is the current standard configuration for ILS Proton. This configuration provides 6150 kg of GTO performance, which is an increase of 1150 kg over the original Proton-M Briz-M, while maintaining the fundamental design configuration.
Khrunichev has initiated development of a set of phase IV enhancements in order to keep pace with market demands and the mass growth trends of commercial satellites. The implementation of Phase IV Proton Briz-M enhancements will be completed in 2013. The Payloads Systems Mass performance for phase IV has been increased to 6300 kg to a reference GTO orbit with 1500 m/s of residual delta V to GSO.
In August 2012, the Russian Federal Space Agency lost both a Russian and Indonesian communications satellite in an attempt to bring them in orbit using a Proton-M rocket. The satellites didn't make it into orbit due to technical difficulties with the last stage of the Proton-M.
Significant upgrades were temporarily put on hold following announcement of the new Angara launch vehicle. The single largest upgrade was the KVRB stage. This cryogenic stage would have greatly increased capacity. The engine was developed successfully, and the stage as a whole had progressed to hardware. However, as KVRB is noticeably larger than Blok D, the vehicle's aerodynamics, flight control, software, and possibly electronics would have to be reevaluated. In addition, the launch pad can supply existing Protons with common hypergol fuels from single sources. The upper stages, in particular, are fed by common loading pipes running along the rocket. Switching to a stage with different fuels requires the addition of extra support articles; switching to cryogens requires that such support articles top off the stage periodically.
Heavy variants of Angara will be simpler and cheaper than Proton (and like the new Atlas V rocket, will not use hypergolics; instead, it will use the same RP-1 fuel as that used on the Soyuz rocket). They will also be designed from the start to accept a KVRB stage, and will already have a LOX supply at the pad; only a hydrogen supply will be called upon. However, delays in Angara development mean that Protons will continue to fly for some time.
Similar launch systems[ပြင်ဆင်ရန်]
- Proton Mission Planner's Guide. International Launch Services.
- Proton Verticalization, Pad 39, Baikonur. flickr (September 5, 2005).
- Template:Cite press
- Proton Heritage. International Launch Services.
- Statement by Vladimir Ye.Nesterov, Khrunichev Director-General, at Press Conference on 15 July 2010 Khruhichev 2010-07-29.
- Murphy, Ronan (December 2009). ILS Reaps Reward of Khrunichev Takeover (PDF) 28–31. Satellite Finance.
- Proton launches page on LyngSat
- Proton rocket specifications sheet
- Proton M Debuts With Successful Ekran Launch on April 7, 2001
- Proton 8K82K / Briz-M. Astronautix.
- FAS - Proton Launch Vehicle
- ILS Proton
- Proton launch schedules on Satlaunch
- Слабое звено - "Бриз-М"