Encyclopedia Astronautica

Credit: © Mark Wade
MAKS mockup - aft
MAKS mock-up - aft view of RD-701 engines
Credit: Dr.Vadim P.Lukashevich
Glushko lox/lh2/kerosene tripropellant rocket engine for air-launched MAKS spaceplane. 4003 kN. Development ended 1988. Isp=415 / 460s. First flight 2001.

The RD-701 was developed for the 22 tonne MAKS spaceplane, which was to have been launched at an altitude of 8 kilometres from the back of a behemoth An-225 Mriya transport. It was planned for 15 re-uses and featured both first and second stage engine characteristics in one reusable package. The tripropellant engine used dense kerosene and liquid oxygen for initial operations, then switched modes to a more modest thrust and higher specific impulse using low density liquid hydrogen and liquid oxygen. This reduced the huge hydrogen tank otherwise required. The state pulled out of the venture in cutbacks following perestroika but it was an extremely effective engine. A 9,000 kgf experimental engine with 19 injectors was tested. There were 50 test burns proving the separate modes and a smooth switch between them. Energomash states that if additional investment could be found use of the engine would lead to a 10 x cut in payload launch costs and make the development of a SSTO vehicle possible (VTOVL). Mass: 3990 kg assembly, 1840 kg each dry. Length: 5.4 m extension down, 3.8 m extension up. Diameter: 2.4 m. Engine Cycle: closed staged combustion. Oxidizer: LOX. Fuel: mode 1: hydrogen and kerosene. mode 2: hydrogen. Mixture Ratio: (O/F. mass) mode 1: 5.27:1 kerosene and 13.2:1 hydrogen. mode 2: 6.1:1. Flow Rate (each chamber, kg/s) mode 1: 388.4 LOX, 29.5 LH2, and 73.7 kerosene. mode 2: 148.5 LOX and 24.7 LH2. Thrust (each chamber, vac): 1960 kN mode 1 and 785 kN mode 2 (throttle 40-100%). Isp: mode 1: 415 sec and 330 sea level. mode 2: 460 sec. Chamber Pressure: mode 1: 290 atm. mode 2: 122 atm. Expansion Ratio: 170 extension down and 70 extension up. Developed 1986-on. Two identical engines with common booster pump set. Chamber pressure 294 / 124 bar. Specific impulse 415 / 460 sec.

Application: MAKS spaceplane.


Chambers: 2. Throttled thrust(vac): 1,588.000 kN (356,996 lbf). Thrust (sl): 1,406.100 kN (316,104 lbf). Thrust (sl): 143,384 kgf. Engine: 3,670 kg (8,090 lb). Chamber Pressure: 294.00 bar. Area Ratio: 133.8. Thrust to Weight Ratio: 111.22. Oxidizer to Fuel Ratio: 6.

Status: Development ended 1988.
Unfuelled mass: 3,670 kg (8,090 lb).
Height: 5.70 m (18.70 ft).
Diameter: 2.30 m (7.50 ft).
Thrust: 4,003.00 kN (899,910 lbf).
Specific impulse: 415 s.
Specific impulse sea level: 330 s.
Burn time: 440 s.
First Launch: 1988-.

More... - Chronology...

Associated Countries
See also
Associated Launch Vehicles
  • MAKS Russian air-launched winged orbital launch vehicle. The MAKS spaceplane was the ultimate development of the air-launched spaceplane studies conducted by NPO Molniya. The draft project for MAKS was completed in 1988 and consisted of 220 volumes, generated by NPO Molniya and 70 sub-contractors and government institutes. Development of MAKS was authorised but cancelled in 1991. At the time of the cancellation, mock-ups of both the MAKS orbiter and the external tank had been finished. A 9,000 kgf experimental engine with 19 injectors was tested. There were 50 test burns proving the separate modes and a smooth switch between them. Since it was expected that MAKS could reduce the cost of transport to earth orbit by a factor of ten, it was hoped in the 1990's that development funding could be found. However this did not materialise. MAKS was to have flown by 1998. More...

Associated Manufacturers and Agencies
  • Glushko Russian manufacturer of rocket engines and rockets. Glushko Design Bureau, Russia. More...

Associated Propellants
  • Lox/Kerosene/LH2 Tripropellant motors use high-density kerosene for the boost phase, then low-density, high-performance liquid hydrogen for the later stages of ascent. However the propellants are stored in separate tanks. The fuel density indicated is the average for the MAKS design, which burned 17,850 kg LH2 and 18,698 Kerosene to reach orbit using 175,758 kg of liquid oxygen oxidiser. More...

  • Salmon, Andrew, The Story Of Russian Rocket Engines - Energomash Museum, Commentary by the guide at the Energomash rocket engine museum in Khimki, April 1998 at YSC98..
  • Haeseler, Dietrich, Information from NPO Energomash museum exhibit, Nov. 1992 via Dietrich Haeseler.
  • Haeseler, Dietrich, Catalogue and datasheets at Moscow Aerospace Exhibition, Moscow-Shukovski, 1995 via Dietrich Haesele.

Associated Stages
  • MAKS Orbiter Lox/Kerosene/LH2 propellant rocket stage. Loaded/empty mass 18,600/18,600 kg. Thrust 3,618.77 kN. Vacuum specific impulse 437 seconds. Empty mass without 9300 kg payload. More...

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