Blok D () is an

upper stage A multistage rocket or step rocket is a launch vehicle that uses two or more rocket ''stages'', each of which contains its own Rocket engine, engines and Rocket propellant, propellant. A ''tandem'' or ''serial'' stage is mounted on top of anoth ...

used on

Soviet The Union of Soviet Socialist Republics. (USSR), commonly known as the Soviet Union, was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 until Dissolution of the Soviet ...

and later

Russia Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...

expendable launch system An expendable launch system (or expendable launch vehicle/ELV) is a launch vehicle that can be launched only once, after which its components are destroyed during reentry or impact with Earth, or discarded in space. ELVs typically consist of s ...

s, including the N1,

Proton-K The Proton-K, also designated Proton 8K82K after its GRAU index or SL-12 after its model number, was a Russian, previously Soviet, carrier rocket derived from the earlier Proton. It was built by Khrunichev, and launched from sites 81/23, 8 ...

and Zenit. The stage (and its derivatives) has been included in more than 320 launched rockets . By 2002 its modification Blok DM had a 97% success rate in 218 flights since 1974, and 43 successful missions in 1997–2002. The stage was developed in the 1960s as the fifth stage (' Д' is the fifth letter in the Cyrillic alphabet) for the powerful

N1 rocket The N1 (from , "Carrier Rocket"; Cyrillic: Н1) was a super heavy-lift launch vehicle intended to deliver payloads beyond low Earth orbit. The N1 was the Soviet counterpart to the US Saturn V and was intended to enable crewed travel to the Mo ...

used in the

Soviet crewed lunar programs The Soviet crewed lunar programs were a series of programs pursued by the Soviet Union to Moon landing, land humans on the Moon, Space Race, in competition with the United States Apollo program. The Soviet government publicly denied participat ...

. The stage first flew in March 1967 while testing the Zond 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 decelerate moon-lander out onto its landing trajectory. Blok D was also included as fourth stage of

and as such flew on uncrewed Soviet missions to Moon,

Mars Mars is the fourth planet from the Sun. It is also known as the "Red Planet", because of its orange-red appearance. Mars is a desert-like rocky planet with a tenuous carbon dioxide () atmosphere. At the average surface level the atmosph ...

(

Mars 3 Mars 3 was a robotic space probe of the Soviet Mars program, launched May 28, 1971, nine days after its twin spacecraft Mars 2. The probes were identical robotic spacecraft launched by Proton-K rockets with a Blok D upper stage, each consisti ...

) and

Venus Venus is the second planet from the Sun. It is often called Earth's "twin" or "sister" planet for having almost the same size and mass, and the closest orbit to Earth's. While both are rocky planets, Venus has an atmosphere much thicker ...

. It was used in the

configuration of the rocket and is still in use in the newer

Proton-M The Proton-M, (Протон-М) GRAU index 8K82M or , is an Expendable launch system, expendable Russian heavy-lift launch vehicle derived from the Soviet Union, Soviet-developed Proton (rocket family), Proton. It is built by Khrunichev State R ...

variant (along with the

Briz-M The Briz-K, Briz-KM and Briz-M ( meaning ''Breeze-K, KM and M'') are Russian liquid-propellant rocket orbit insertion upper stages manufactured by Khrunichev State Research and Production Space Center and used on the Proton-M and Angara A5. T ...

). Blok DM also flies as the third stage for the Zenit-3SL rocket, which is used by the

Sea Launch Sea Launch was a multinational—Norway, Russia, Ukraine, United States—spacecraft launch company founded in 1995 that provided orbital launch services from 1999 to 2014. The company used a mobile maritime launch platform for equatorial l ...

project to launch geostationary satellites. In 2002 a Blok DM3 failed in the attempted launch of

Astra 1K Astra 1K was a communications satellite manufactured by Alcatel Space for SES (company), SES. When it was launched on 25 November 2002, it was the largest civilian communications satellite ever launched, with a mass of . Intended to replace the ...

. The stage uses

liquid oxygen Liquid oxygen, sometimes abbreviated as LOX or LOXygen, is a clear cyan liquid form of dioxygen . It was used as the oxidizer in the first liquid-fueled rocket invented in 1926 by Robert H. Goddard, an application which is ongoing. Physical ...

(LOX) and

kerosene Kerosene, or paraffin, is a combustibility, combustible hydrocarbon liquid which is derived from petroleum. It is widely used as a fuel in Aviation fuel, aviation as well as households. Its name derives from the Greek (''kērós'') meaning " ...

as propellants, and has one single-chamber

RD-58 The RD-58 (, GRAU index: 11D58) is a rocket engine, developed in the 1960s by OKB-1, now RKK Energia. The project was managed by Mikhail Melnikov, and it was based on the previous S1.5400 which was the first staged combustion engine in the wo ...

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 as Blok DM in 1974, with 11D-58S engine. The unit cost is $4 million. As of the early 1990s, the ullage 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 to

space debris Space debris (also known as space junk, space pollution, space waste, space trash, space garbage, or cosmic debris) are defunct human-made objects in spaceprincipally in Earth orbitwhich no longer serve a useful function. These include dere ...

. Since 1990, all variations of this stage have been built in the

Krasnoyarsk Machine-Building Plant Krasnoyarsk Machine-Building Plant (stylized KrasMash) () is a Russian arms manufacturer and home appliance manufacturer based in Krasnoyarsk. It was established in 1932 and became a subsidiary of Roscosmos. The Krasnoyarsk Machine-Building Pla ...

Modifications

RKK Energia S.P. Korolev Rocket and Space Corporation "Energia" () is a Russian manufacturer of spacecraft and space station components. Its name is derived from the Russian word for energy and is also named for Sergei Pavlovich Korolev, the first chief o ...

, 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 on Buran started as a modification of the Blok D.

Variants

References

External links

Russian Space Web
* https://web.archive.org/web/20120716190506/http://www.friends-partners.org/oldfriends/jgreen/blockd.html

{{N1-L3 Soviet inventions Rocket stages Rocket engines using kerosene propellant

Modifications

Variants

See also

References

External links