From the beginning of the program a Zenit-3 version was proposed for geosynchronous launches using the N1/Proton Block D third stage. This had the potential of replacing the Proton in the role of geosynchronous launcher. It was considered for launch from Australia / Cape York in the 1980's. Finally a joint US-Norwegian-Ukraininan-Russian consortium was formed to launch the three stage commercial Zenit from a floating launch platform in the Pacific Ocean,

Launches: 4. Failures: 1. Success Rate: 75.00% pct. First Launch Date: 28 March 1999. Last Launch Date: 28 July 2000. Payload: 5,250 kg. to a: Geosynchronous transfer trajectory. Liftoff Thrust: 740,000 kgf. Total Mass: 471,000 kg. Core Diameter: 3.9 m. Total Length: 59.6 m. Launch Price $: 90.00 million. in 1999 price dollars.

• Stage Number: 1. 1 x Zenit-1 Gross Mass: 354,300 kg. Empty Mass: 28,600 kg. Thrust (vac): 834,243 kgf. Isp: 337 sec. Burn time: 150 sec. Isp(sl): 311 sec. Diameter: 3.9 m. Span: 3.9 m. Length: 32.9 m. Propellants: Lox/Kerosene No Engines: 1. RD-171

• Stage Number: 2. 1 x Zenit-2 Gross Mass: 90,600 kg. Empty Mass: 9,000 kg. Thrust (vac): 93,000 kgf. Isp: 349 sec. Burn time: 315 sec. Isp(sl): 0 sec. Diameter: 3.9 m. Span: 3.9 m. Length: 11.5 m. Propellants: Lox/Kerosene No Engines: 1. RD-120

• Stage Number: 3. 1 x Zenit-3 Gross Mass: 17,300 kg. Empty Mass: 2,720 kg. Thrust (vac): 8,660 kgf. Isp: 352 sec. Burn time: 650 sec. Diameter: 3.7 m. Span: 3.7 m. Length: 5.6 m. Propellants: Lox/Kerosene No Engines: 1. RD-58M

• DemoSat Payload: HS 702. Mass: 4,500 kg.

  The first Boeing Sea Launch mission. The Zenit-3SL lifted off from the Odyssey floating platform on the equator at 154 degrees West longitude. The DemoSat payload was an instrumented dynamic model of an HS-702 satellite built by Boeing Commercial Space/Kent. 13 minutes after launch, the Block DM-SL upper stage completed its first burn and entered a 180 km x 735 km x 1.2 degree parking orbit. A second burn 47 minutes after launch placed DemoSat in a 638 km x 36,064 km x 1.2 degree geostationary transfer orbit. Three hours later, a third DM-SL burn lowered the stage's perigee so that it would re-enter quickly.

• DirecTV 1R Spacecraft: HS 601 .

  Second successful Zenit-3SL flight from the Odyssey launch platform in the Pacific Ocean at 154 deg W, 0 deg N. First flight to carry a commercial payload. The satellite used its R-4D apogee engine to enter geostationary orbit at 81.6 deg W. Finally stationed at 101 deg W.

• ICO F-1 Spacecraft: HS 601. Payload: ICO-F1. Mass: 2,750 kg.

  First ICO Global Communications satellite. Lost due to launch vehicle failure; was to have entered a 10,300 km x 45 deg circular orbit. ICO's satellites would carry multiple spot beams for mobile communications.

• PAS 9 Spacecraft: HS 601.

  Panamsat geosynchronous communications satellite to replace PAS 5 at 58 deg W. Stationed at 58 deg W.

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  Bibliography:
  • 42 - Isakowitz, Steven J,, International Reference to Space Launch Systems Second Edition, AIAA, Washington DC, 1991.
  • 61 - Wilson, Andrew, editor,, Jane's/Interavia Space Directory, Jane's Information Group, Coulsdon, Surrey, 1992 et al.
  • 455 - Isakowitz, Steven J,, International Reference to Space Launch Systems Third Edition, AIAA, Washington DC, 2000.

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