 Comparison of Block D variants | |
| Country of origin | Soviet Union |
|---|---|
| Used on | |
| General characteristics | |
| Height | 6.28 m (20 ft 7 in) |
| Diameter | 3.70 m (12 ft 2 in) |
| Gross mass | 17,360 kg (38,270 lb) |
| Propellant mass | 15,220 kg (33,550 lb) |
| Empty mass | 2,140 kg (4,720 lb) |
| Associated stages | |
| Derivatives | Blok DM-03 |
| Comparable | Briz-M |
| Launch history | |
| Status | Retired |
| Total launches | 66 |
| First flight | 26 March 1974 |
| Last flight | 6 May 1988 |
| Blok DM | |
| Powered by | 1 ×RD-58M |
| Maximum thrust | 83.61 kN (18,800 lbf) |
| Specific impulse | 363.5 s (3.565 km/s) |
| Burn time | 630 seconds |
| Propellant | RP-1/LOX |
Blok D (Russian:Блок Д,lit. 'Block D') is anupper stage used onSoviet and laterRussianexpendable launch systems, including theN1,Proton-K andZenit.[2]
The stage (and its derivatives) has been included in more than 320 launched rockets as of 2015[update].[3] By 2002 its modification Blok DM had a 97% success rate in 218 flights since 1974, and 43 successful missions in 1997–2002.[4][5]
The stage was developed in the 1960s as the fifth stage ('Д' is the fifth letter in the Cyrillic alphabet) for the powerfulN1 rocket used in theSoviet crewed lunar programs. The stage first flew in March 1967 while testing theZond spacecraft as a part of those programs. During crewed lunar flight Blok D would be used for mid-course corrections on the flight to the Moon, then to place the lunar orbiter and lander into a lunar orbit, and deceleratemoon-lander out onto its landing trajectory.[6]
Blok D was also included as fourth stage ofProton-K and as such flew on uncrewed Soviet missions to Moon,Mars (Mars 3) andVenus. It was used in theProton-K configuration of the rocket and is still in use in the newerProton-M variant (along with theBriz-M).
Blok DM also flies as the third stage for the Zenit-3SL rocket, which is used by theSea Launch project to launch geostationary satellites. In 2002 a Blok DM3 failed in the attempted launch ofAstra 1K.
The stage usesliquid oxygen (LOX) andkerosene as propellants, and has one single-chamberRD-58 main engine. The LOX tank has a spherical shape; the kerosene tank is toroidal, inclined to 15 degrees for better fuel extraction, with the engine mounted in the center of torus. Tanks include the first pump stage for the engine; the main pump is mounted on the engine.
Blok D weighs 3.5 tons during liftoff, but some parts are jettisoned and the dry mass in space is 2.5 tons. It has 5.70 meters length and generates 83.300 kN thrust for 600 seconds burn time. Blok D was modified asBlok DM in 1974, with 11D-58S engine. The unit cost is $4 million.[7]
As of the early 1990s, theullage rockets discarded just before the final burns by Block DM fourth stages on Proton launches constituted the largest single group of soviet propulsion systems to have suffered disintegrations contributing tospace debris.[8]
Since 1990, all variations of this stage have been built in theKrasnoyarsk Machine-Building Plant.[9]
RKK Energia, the company that created Blok D, used it as a platform for many modifications over many years for different purposes; for example, the main propulsion unit onBuran started as a modification of the Blok D.[10]
| Variant | First flight | Last flight | Launches | Rockets | Remarks |
|---|---|---|---|---|---|
| Blok D | 1967 | 1976 | 44 | Proton-K N1 | |
| Blok D-1 | 1978 | 1989 | 10 | Proton-K | Mostly used for launches toVenus |
| Blok D-2 | 1988 | 1996 | 3 | Proton-K | LaunchedFobos 1,Fobos 2 andMars 96 |
| Blok DM | 1974 | 1990 | 66 | Proton-K Energia (unflown) | Blok D modification for Earth-based orbits |
| Blok DM-2 | 1982 | 2012 | 115 | Proton-K Proton-M | Used with Proton-M forGLONASS launches[11] |
| Blok DM-2M | 1994 | 2005 | 15 | Proton-K | Enhanced payload thanks to the use of higher performanceSyntin fuel instead ofRG-1. Powered by theRD-58S engine. |
| Blok DM-5 | 1997 | 2002 | 2 | Proton-K | Used forlow Earth orbit launches withAraks satellites |
| Blok DM1 | 1996 | 1996 | 1 | Proton-K | Commercial Blok DM-2, only used for one launch, withInmarsat-3 F2 |
| Blok DM2 | 1997 | 2002 | 4 | Proton-K | Commercial Blok DM-5, used forIridium andINTEGRAL launches |
| Blok DM3 | 1996 | 2006 | 25 | Proton-K | Commercial Blok DM-2M |
| Blok DM4 | 1997 | 1997 | 1 | Proton-K | Commercial Blok DM-2M, only used to launchTelstar 5 |
| Blok DM-SL | 1999 | 2014 | 36 | Zenit-3SL | Used inSea Launch missions, some flights use a version with stretched fuel tanks |
| Blok DM-SLB | 2008 | 2013 | 5 | Zenit-3SLB | Used inLand Launch missions and other commercialZenit-3SLB flights from Baikonur |
| Blok DM-03 | 2010 | active | 4 | Proton-M | Intended as a replacement for Blok DM-2 and DM-SL/SLB, first flew in 2010, only used on Proton |
| 14S48 Persei / Orion | 2021 | active | 1 | Angara A5 | Modification of 11S861-03 (DM-03) forAngara A5 |
| References | [3][12][13] | ||||
| Launch vehicles and ascent/upper stages |  | |
|---|---|---|
| Spacecraft | ||
| Other hardware | ||
| Soyuzdocking tests | ||
| Zond (7K-L1/L1S) lunar flyby missions | ||
| LOK (7K-LOK/L1E) test missions | ||
| LK Lander (T2K) test missions | ||
The † sign designates failed missions.Italics designates cancelled missions. | ||
