Phobos 1, and its companion spacecraft Phobos 2, were the next-generation in
the Venera-type planetary missions, succeeding those last used during the Vega 1 and 2
missions to comet P/Halley. The objectives of the Phobos missions were to:
- conduct studies of the interplanetary environment;
- perform observations of the Sun;
- characterize the plasma environment in the Martian vicinity;
- conduct surface and atmospheric studies of Mars; and,
- study the surface composition of the Martian satellite Phobos.
The main section of the spacecraft consisted of a pressurized toroidal electronics section surrounding a modular cylindrical experiment section. Below these were mounted four spherical tanks containing hydrazine for attitude control and, after the main propulsion module was to be jettisoned, orbit adjustment. A total of 28 thrusters (twenty-four 50 N thrusters and four 10 N thrusters) were mounted on the spherical tanks with additional thrusters mounted on the spacecraft body and solar panels. Attitude was maintained through the use of a three-axis control system with pointing maintained with sun and star sensors.
Phobos 1 operated nominally until an expected communications session on 2 September 1988 failed to occur. The failure of controllers to regain contact with the spacecraft was traced to an error in the software uploaded on 29/30 August which had deactivated the attitude thrusters. This resulted in a loss of lock on the Sun, resulting in the spacecraft orienting the solar arrays away from the Sun, thus depleting the batteries.
Phobos 2 operated nominally throughout its cruise and Mars orbital insertion phases, gathering data on the Sun, interplanetary medium, Mars, and Phobos. Shortly before the final phase of the mission, during which the spacecraft was to approach within 50 m of Phobos' surface and release two landers, one a mobile 'hopper', the other a stationary platform, contact with Phobos 2 was lost. The mission ended when the spacecraft signal failed to be successfully reacquired on 27 March 1989. The cause of the failure was determined to be a malfunction of the on-board computer.
Facts
Launch Date:
07 July 1988 (Phobos 1) and 21 July 1988 (Phobos 2)Launch Vehicle: Proton-K
Mass: 2600 Kg (6220 Kg with orbital insertion hardware attached)
Power System: Solar panels
Phobos 1 Experiments
Flux Gate Magnetometer Mars (FGMM) (Principal Investigator: Sauer)
Magnetic Fields near Mars (MAGMA) (Principal Investigator: Schwingenschuh)
Automatic Space Plasma Experiment with Rotating Analyzer (ASPERA) (Principal Investigator: Lundin)Proton and Alpha Particle Spectrometer (TAUS) (Principal Investigator: Rosenbauer)
Plasma Wave System (PWS) (Principal Investigator: Grard)
Ion and Electron Spectrometer (HARP) (Principal Investigator: Shutte)
Energy, Mass, and Charge Spectrometer (SOVIKOMS)
Energetic Charged-Particle Spectrometer (SLED)Solar Photometer (IPHIR)
X-Ray Photometer (RF-15)
Ultrasound Spectrometer (SUFR)
Gamma-Ray Burst Spectrometer (LILAS)
Gamma-Ray Burst Spectrometer (VGS)
Videospectrometric System (VSK)
Infrared Spectrometer (ISM)
Gamma Ray Emission Spectrometer (APEX)
Radar System (RLK)
Laser Mass Spectrometer Analyzer (LIMA-D)
Secondary Ion Mass Analyzer (DION)
Optical Radiation Spectrometer (AUGUST) (Principal Investigator: Blamont)
Neutron Detector (IPNM)
Solar Telescope/Coronograph (TEREK)
Phobos 2 Experiments
Flux Gate Magnetometer Mars (FGMM)
Magnetic Fields near Mars (MAGMA)
Automatic Space Plasma Experiment with Rotating Analyzer (ASPERA)
Proton and Alpha Particle Spectrometer (TAUS)
Plasma Wave System (PWS)
Ion and Electron Spectrometer (HARP)
Energy, Mass, and Charge Spectrometer (SOVIKOMS)
Energetic Charged-Particle Spectrometer (SLED)
Solar Photometer (IPHIR)
X-Ray Photometer (RF-15)
Ultrasound Spectrometer (SUFR)
Gamma-Ray Burst Spectrometer (LILAS)
Gamma-Ray Burst Spectrometer (VGS)
Videospectrometric System (VSK)
Infrared Spectrometer (ISM)
Gamma Ray Emission Spectrometer (APEX)
Radar System (RLK)
Laser Mass Spectrometer Analyzer (LIMA-D)
Secondary Ion Mass Analyzer (DION)Optical Radiation Spectrometer (AUGUST)
Infrared Radiometer/Spectrometer (KRFM)
Scanning Infrared Radiometer (Thermoscan)