Proton rocket

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Proton 8K82K
Launch of a Proton rocket. (NASA)
Launch Vehicle	1st Launch March 10, 1967
Payload LEO 51-deg	22,000 kg
Payload GTO	6,000 kg
Payload Escape Velocity	5,800 kg

The Proton (Прото́н) rocket (formal designation: UR-500, also known as D-1/ D-1e or SL-12/SL-13) is a Russian unmanned space vehicle design, first launched in 1965. It is still in use as of 2006, for both commercial and government launches. This makes it one of the most successful heavy boosters in the history of spaceflight. All Protons launch from the Baikonur facility.

The name "Proton" originates from a series of large scientific satellites, which were among the rocket's first payloads. The enormous capacity of the new rocket allowed the heavy materials used in particle detectors. Thus the Proton satellites were pioneers of high-energy astronomy. Like many Soviet boosters, the name of the recurring payloads became associated with their launchers.

Launch capacity to low Earth orbit is about 22 tonnes (44,000 lbm). Interplanetary transfer capacity is about 5–6 tonnes (11,000–13,000 lbm).

Comparable rockets: Delta IV - Atlas V - Ariane 5 - Chang Zheng 5 - Angara - Falcon 9

Contents 1 History 2 Proton 8K82K 3 Proton M 3.1 Proton M stages 4 Future Developments 5 External links

[edit] History

Proton initially started life as a "super ICBM." It was designed to throw a 10-Megaton (or larger) nuclear warhead over a distance of 12,000 km. It was hugely oversized for an ICBM, and was never used 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 programme, 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 300 launches, it has a 96% success rate.

Proton launched the unmanned Soviet circumlunar flights, and would very likely have launched the first humans to circle the Moon had the flight of Apollo 8 been conducted as originally planned (i.e. without going to lunar orbit). 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, until divestment in 2006-2007.

On March 1, 2006, a Proton-M rocket failed to launch Arabsat 4A. Following successful first, second, and third stage burns, its upper stage shut down early and failed to place Arabsat 4A into its proper geostationary orbit. An investigation concluded that a foreign particle in the upper stage oxidizer system blocked a pump nozzle, causing the shutdown. After changes were made to resolve the problems, the Proton-M successfully launched the European Hot Bird 8 satellite on 5 August 2006. [1]. On February 19, 2007, the upper stage which failed to bring Arabsat 4A to its correct orbit exploded over Australia after almost a year in space, creating a cloud of space debris. [2]

[edit] Proton 8K82K

Proton's version, designated with GRAU index 8K82K 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 low-temperature-tolerant components, and allows the rocket to sit on the pad indefinitely (the only other rockets with such capability were the U.S. Titan II, Titan III, and Titan IV rockets). In contrast, cryogenic fuels need periodic topping-up of propellants as they boil off. Hypergols are, however, very toxic fuels, requiring special handling by highly trained labor. When first and second stages impact downrange, Russia must pay for cleanup of residual fuel, similar in essence to the clean up of debris after the break-up of the Space Shuttle Columbia in 2003.

Note that the six structures around the base of the vehicle are not booster rockets, and do not detach from the core structure, even though each one appears to have its own engine. Rather, the core is the oxidizer tank, and the six units are outrigger fuel tanks. This entire assembly forms a stage, which separates as one piece from the second stage at the lattice structure. Outrigger tanks reduce sloshing, compared to the short, wide fuel and oxidizer tanks that would have been used in a standard, tandem configuration. They may also be cheaper to fabricate. They raise the specter of uneven fuel consumption and flight instability, however (the Titan rockets avoided this by having its fuel and oxidizer tanks located in the body itself, thus the Titan II and III rockets can be flown with or without solid boosters).

First-stage guidance was open-loop. Though this method is quite simple, it required significant amounts of propellant to be held in reserve. This reduces payload.

The second stage ignites while still attached to the first stage (a "fire in the hole" event, not done by the Titans, as they required in-flight staging, then ignition). Exhaust gases escape through the lattice. The forward dome of the first-stage oxidizer tank is insulated to retain integrity until stage separation.

The RD-0210 engine of the third stage consists of a main engine, and four vernier nozzles with common systems. The main engine does not gimbal; the verniers provide steering, and also act as separation aids and ullage rockets. Ducts are built into the structure to channel vernier exhaust before stage separation. The stage's guidance electronics are also in charge of first- and second-stage flight.

The fourth stage came in multiple variants, depending on 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 conventional oxidizer tank.

Stage Number	1. Proton K-1	2. Proton K-2	3. Proton K-3	4. Proton 11S824
Gross Mass	450,510 kg	167,828 kg	50,747 kg	13,360 kg
Empty Mass	31,100 kg	11,715 kg	4,185 kg	1,800 kg
Thrust (vac)	10,470 kN	2,399 kN	630 kN	83 kN
Isp	316 s (3.10 kN·s/kg)	327 s (3.21 kN·s/kg)	325 s (3.19 kN·s/kg)	346 s (3.39 kN·s/kg)
Burn time	124 s	206 s	238 s	470 s
Isp(sl)	267 s (2.62 kN·s/kg)	230 s (2.26 kN·s/kg)
Diameter	4.15 m	4.15 m	4.15 m	3.70 m
Span	7.40 m
Length	21.20 m	14.00 m	6.50 m	5.50 m
Propellants	N2O4/UDMH	N2O4/UDMH	N2O4/UDMH	Lox/Kerosene
Engines	6 x RD-253-11D48	4 x RD-0210	1 xRD-0212	1 x RD-58
Other designations	8S810K (GRAU index)	8S811K. (GRAU index)		11S824 (GRAU index); Block D; D-1-e.

[edit] Proton M

The latest version is the Proton M. A Proton M can launch 3 to 3.2 tonnes (6600 to 7050 lbm) into geostationary orbit or 5.5 tonnes (12,100 lbm) into a geostationary transfer orbit. It can place up to 22 tonnes (48,500 lbm) 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. By using modern, closed-loop control for the first stage, its propellants could be consumed more completely, increasing performance slightly and reducing release of toxic chemicals in stage impact areas. A Breeze-M storable propellant upper stage replaces the Block D stage. Efforts were also made to reduce dependency on foreign (usually Ukrainian) component suppliers.

• LEO Payload: 21,000 kg to 185 km orbit at 51.6 degrees
• Payload: 2,920 kg to a geosynchronous orbital trajectory.
• Apogee: 40,000 km
• Associated Spacecraft: Gorizont, Raduga, Spacebus 3000
• Liftoff Thrust: 965,580 kgf 9,469.1 kN
• Total Mass: 712,800 kg
• Core Diameter: 7.40 m. Total Length: 53.00 m.

[edit] Proton M stages

Stage	Proton KM-1	Proton K-2 8S811K	Proton K-3	Proton KM-4 Briz-M
Gross Mass	450,400 kg	167,828 kg	50,747 kg	22,170 kg
Empty Mass	31,000 kg	11,715 kg	4,185 kg	2,370 kg
Thrust (vac)	1,074,000 kgf	244,652 kgf	64,260 kgf	2,000 kgf
Isp	317 s	327 s	325 s	326 s
Burn time	108 s	206 s	238 s	3,000 s
Isp(sl)	285 s	230 s	230 s
Diameter	7.40 m	4.15 m	4.15 m	2.50 m
Span	7.40 m	4.15 m	4.15 m	4.10 m
Length	21.00 m	14.00 m	6.50 m	2.61 m
Propellants	N2O4/UDMH	N2O4/UDMH	N2O4/UDMH	N2O4/UDMH
Engines	6 x RD-253-14D14	4 x RD-0210	1 x RD-0212	1 x S5.98M
Status	In production	In production	In production	In production

[edit] Future Developments

Significant upgrades were put on hold following announcement of the new Angara launch vehicle. 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). However, delays in Angara development mean that Protons will continue to fly for some time.

[edit] External links

• Proton rocket specifications sheet
• Proton M Debuts With Successful Ekran Launch on April 7, 2001
• Proton 8K82K / Briz-M (www.astronautix.com)

v • d • e  Soviet (to 1991) and Russian expendable launch vehicles

Active: Cosmos-3M | Dnepr | Molniya | Proton | Rockot | Shtil' | Soyuz (U, 2) | START-1 | Strela | Tsyklon | Volna | Zenit

In Development: Angara | Onega

Past: Energia | N1 | Polyot | R-7 Semyorka | Voskhod | Vostok