Please make a donation to support Gunter's Space Page.
Thank you very much for visiting Gunter's Space Page. I hope that this site is useful and informative for you.
If you appreciate the information provided on this site, please consider supporting my work by making a simple and secure donation via PayPal. Please help to run the website and keep everything free of charge. Thank you very much.



The Plasma-A satellites were technological test spacecraft to test out new systems for the US-AM RORSATs. It was based on the US-A RORSAT bus, but was fitted with the new Topaz nuclear rector, which used thermo-emission conversion method to convert heat to electricity. Topaz provided over 10 kW of power and had long endurance and storage in a radiation-safe orbit.

Plazma-A did not have the radar of the US-A spacecraft, but tested a number of other systems:

  • electrostatic manoeuvring engines (6 × SPT-70 Stationary Plasma Thrusters)
  • ion orientation and stabilisation engines
  • solar sensors
  • magnetic momentum compensators
  • multi-channel wave devices

The Plasma-A satellites carried instruments to map the magnetic field of the earth for the development of a magnetic navigation system.

Two Plasma-A space craft were successfully launched on Tsiklon-2 rockets. Due to the higher orbit than the US-A spacecraft, the reactors were not separated and boosted into a storage orbit.

Nation: USSR
Type / Application: Technology, nuclear reactor
Configuration: US Bus
Propulsion: 6 × SPT-70 Stationary Plasma Thrusters
Power: Topaz-1 nuclear reactor
Mass: 3550 kg
Orbit: 774 km × 803 km, 65.0
Satellite COSPAR Date LS Launch Vehicle Remarks
Kosmos 1818 (Plasma-A #1) 1987-011A 01.02.1987 Ba LC-90 Tsiklon-2
Kosmos 1867 (Plasma-A #2) 1987-060A 10.07.1987 Ba LC-90 Tsiklon-2

Cite this page: