PROTON ROCKET

The 'Proton rocket' (Прото́н) (formal designation: 'UR-500') is a rocket used in an expendable launch system for both commercial and Russian government launches. The first Proton was launched in 1965 and the launch system is still in use as of 2007, 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.
Proton Fact Sheet They are transported for launch to the Baikonur Cosmodrome, where they are brought to the launch pad horizontally and then raised into vertical position for launch.^[1]
The name "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'. 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). Commercial launches are marketed by International Launch Services (ILS).
'Comparable rockets:'
Delta IV -
Atlas V -
Ariane 5 -
Chang Zheng 5 -
Angara -
Falcon 9

Contents

History

Proton 8K82K

Proton M

Proton M stages

Proton-M Enhanced

Launches

Future Developments

References

External links

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 13,000 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.
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]
On 5 September 2007, another Proton-M rocket, this time carrying the JCSAT-11 spacecraft, failed. On this occasion, the second stage switched off earlier than the LV reached needed altitude.

Proton 8K82K

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 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 corrosive and toxic fuels, requiring special handling by highly trained labor. When the spent first and second stages impact downrange, Russia must pay for cleanup of the residual fuel.
Note that the six structures around the base of the Proton are not strap on booster rockets, and do not detach from the core structure. There is a central oxidizer tank, and the six units are outrigger fuel tanks. This entire assembly forms the first 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 do however raise the specter of uneven fuel consumption and resulting flight instability. (The Titan rockets avoided this by having the fuel and oxidizer tanks located in the body itself. Thus, unlike the Proton, the Titan II and III rockets can be flown with or without solid boosters.)
The first stage uses six RD-253 engines, designed by Valentin Glushko. RD-253 is a single chamber engine and uses the highly efficient staged combustion cycle. 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 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 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.

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.

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

Proton-M Enhanced

On 7 July 2007, ILS launched the first ''Proton Breeze M Enhanced'' vehicle, which carried the DirecTV-10 satellite into orbit. This was the 326th Proton mission, the 16th Proton Breeze M mission and the 41st ILS Proton mission.^[2] The 'Proton-M Enhanced' features more efficient engines on the first stage, updated avionics, improved tankage and more powerful vernier engines on the Briz-M upper stage, and weight reduction throughout the rocket, including thinner fuel tank walls on the first stage, and use of composite materials on all other stages.

Launches

Main articles: List of Proton launches

Date	Flight	Version	Payload	Notes
April 8 1996		Proton D1-e	Astra 1F	first commercial flight[3][4]
May 20 1999		Proton (Block DM)	Nimiq-1
February 12, 2000		Proton (Block 1 DM)	Garuda 1
30 December 2002		Proton Breeze M	Nimiq-2
07 June 2003		Proton Breeze M	SES Americom AMC-9	300th flight of a Proton[5]
15 March 2004		Proton Breeze M	Eutelsat W3A
16 June 2004		Proton Breeze M	Intelsat-10
05 August 2004		Proton Breeze M	Hispasat Amazonas
28 February 2006		Proton Breeze M	Arabsat-4A	Launch failure[6]
05 August 2006		Proton Breeze M	Eutelsat HotBird-8
09 November 2006		Proton Breeze M	Arabsat-4B
07 July 2007		Proton Breeze M Enhanced	DirecTV-10	First flight of an enhanced Proton M
5 September 2007		Proton Breeze M	JCSAT-11	Failure - Failed to reach orbit due to malfunction of 2nd stage.

; Planned

Date	Flight	Payload
December 2008	ISS assembly flight 3R	Multipurpose Laboratory Module and European Robotic Arm
Late 2008		Ciel-2[7]

Future Developments

Significant upgrades were temporarily 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.

References

1. Proton Verticalization, Pad 39, Baikonur
2.
DIRECTV 10
3. Proton Heritage
4. ASTRA 1F
5. 300th Mission Flown by Proton Vehicle
6. Proton rocket fails in Arab satellite launch
7. ILS PROTON TO LAUNCH CIEL-2 SATELLITE TO SERVE NORTH AMERICA

External links

★ Proton rocket specifications sheet

★ Proton M Debuts With Successful Ekran Launch on April 7, 2001

★ Proton 8K82K / Briz-M (www.astronautix.com)