The core module, launched on 19 Feb 1986 has a mass of approximately 21000 kg, a length of about 13.1m, and a maximum diameter of 4.2 m. It consists primarily of a passage area with five docking ports, a working area housing the command station, living/eating and hygiene facilities, and a propulsion section through which a tunnel allows access to the Kvant module.
Kvant, an astrophysics module that accomodates instruments from several countries, was launched on 31 Mar 1987 and docked to the core module in April 1987. It is about 5.8 m long, has a maximum diameter of 4.15 m, and a mass of about 11 tons.
Kvant-2, housing scientific and technological experiment equipments, a shower facility, and an airlock supporting extravehicular activities (EVA) by the crew, docked to the station in December 1989. It has a mass of 19.5 tons, a length of 11.9 m, and a maximum diameter of 4.35 m.
The Kristall module joined the station in June 1990. It is mainly dedicated to technological research, such as semiconductor and biological experiments. It also houses Earth-observation instruments. Its mass and dimensions are similar to those of Kvant-2.
In August 1992, a thruster package, known as "SOFORA", was installed on a 14 m mast mounted on top of the Kvant module. These thrusters allow efficient and propellant-saving attitude control of the station.
Spektr, a 23.5 ton Russian module, joined Mir in May 1995, and will remain with it for at least 3 years. It carries a Belgian grating spectrometer MIRAS that will monitor atmospheric gases such as ozone, carbon dioxide, freon and sulfur. It also carried some American equipment to implement the Mir-Shuttle rendezvous scheduled for late 1995.
The Priroda module joined Mir in April 1996. It is mainly dedicated to Earth-observation tasks such as ocean surface-temperature measurement and studies of ocean/atmosphere interactions. It was the aim of the project to provide the full variety of existing remote sensing technology using instruments in almost all usable wavelength ranges as well as active and passive sounding methods. So the Priroda module carries optical and infrared scanners, an imaging spectrometer, a LIDAR, scanning and pointing microwave radiometers, synthetic aperture radar and high resolution digital (stereo) cameras.
Logistical resupply of Mir is provided by the unmanned Progress system, with a payload capacity in the order of 2.5 tons. The crew is transported to and from the station with the Soyuz-TM vehicle, which can accomodate three astronauts/cosmonauts per trip. Both the Soyuz-TM and Progress are expendable systems and are launched by the Soyuz launch vehicle. Later the NASA STS (Shuttle) missions also docked with Mir, and have transported crew and materials back and forth.
The results of the experiments, including samples, film, etc., are usually returned to Earth by the astronaut/cosmonaut on board the Soyuz-TM or the Shuttle. A special unmannned re-entry capsule enhances these return capacities.
The REM detector includes two independent sensors able to measure and accumulate the linear energy transfer (LET) of charged particles passing through. Each sensor consists of two thin (ca. 300 mm thick), totally depleted silicon surface barrier diodes covered with a spherical dome. The main aperture of both sensors is defined by an aluminium cone with an opening angle of approximately 45 °, mounted on top of the silicon diodes. A cut view of the REM detector is shown in figure 1. Data is accumulated over a period of 32 seconds and then stored as a 16-bin histogram. The two detectors differ in size (150 mm2 and 50 mm2) and shielding. The smallest detector is covered with a spherical dome of 0.71 mm Al, and the larger detector with a spherical dome of 3 mm Al and an additional 0.75 mm Ta. The backside of both sensors is shielded by the detector housing and the spacecraft, i.e. the MIR station.
The charge pulses produced by particle passing through a silicon diode are measured by a charge sensitive pre-amplifier linked to a 12-bit analog-to-digital convertor (ADC). A programmable compression function reduces the ADC output into a 16-bin histogram. Each histogram bin, i.e. channel, corresponds to a given range of deposited energy.
A built-in pulser connected at the input of the pre-amplifiers allows to check in-flight for proper functioning of the electronics and for dead-time determination. Data is successively accumulated during 31.9 seconds.
One should note that the count rates met by the REM detector aboard the MIR station are sufficiently weak, so that the dead-time correction can be neglected. But, too weak to allow the transformation of single measurements into proton or electron fluxes. Such a transformation can only be performed on multiple measurements.
Remarks:
Bühler, P., A. Mchedlishvili, A. Zehnder, The radiation environment monitor, MIR data preprocessing, Technical report, Paul Scherrer Institut, June 1995.
Bühler, P., STRV-1B and MIR orbit determination, Technical report, Paul Scherrer Institut, March 1996.
Bühler, P., Determination of the MIR-REM observation times, Technical report, Paul Scherrer Institut, November 1996.
Bühler, P., The Radiation Environment Monitor, Scientific Data Extraction, Part I, Technical report, Paul Scherrer Institut, December 1996.
Bühler, P., The Radiation Environment Monitor, Scientific Data Extraction, Part II: REM-CDF database, Technical report, Paul Scherrer Institut, December 1996.
Bühler, P., S. Ljungfelt, A. Mchedlisshvili, N. Schlumpf, A. Zehnder, L. Adams, E. Daly, and R. Nickson, Radiation environment monitor, Nucl. Instr. and Meth. in Phys. Res. A 368, pp. 825-831, 1996.
Bühler, P., L. Desorgher, A. Zehnder, E. Daly, and L. Adams, Observations of the low Earth orbit radiation environment from MIR, Radiat. Meas., 26, No. 6, 917-921, 1996.
Bühler, P., L. Desorgher, A. Zehnder, E. Daly, and L. Adams, REM Measurements aboard Mir during 1995, PSI-PR-97-02, Paul Scherrer Institute, January 1997.
Desorgher L., P. Bühler, A. Zehnder, E. Daly, L. Adams, Outer radiation belt variations during 1995, PSI-PR-97-02, 1997.
Kruglanski, M., Dynamical low-altitude proton model, Appendix A: MIR/REM Proton maps, technical note 2, Trend 4, ESTEC Contract No. 11711/95/NL/JG - CCN 1, 1998.
Lebedev, O., V. Antonov, N. Shvetz, L. Adams, A. Zehnder, Final report on results of REM experiment preparation and realisation on MIR station. Technical report, Rocket and Space Corporation ENERGIA, 1995.