Cosmos 1809 (Ionosonde ) satellite was launched on December 18, 1986 
and had been operating till May 23, 1993, i.e. in the course of 
substantial portion of the 22-th cycle of solar activity.  It was a 
three-axes stabilized spacecraft and was placed into a 960 km circular 
orbit at inclination of 82.5 deg.
   The satellite had the following scientific equipment on board
1. Ionosonde;
2. Impedance probe;
3. High-frequency probe;
4. Mass-spectrometer;
5. Photoelectron Spectrometer;
6. Electric Fields Detector;
7. Low-Frequency Waves Analyser;
8. High-Frequency Waves Analyser.
The ionosonde, the mass-spectrometer and the photoelectron spectrometer 
ceased operations in 1987; the remaining instruments listed above were 
active till the satellite demise. The satellite equipment  worked in 
four memory regimes 1, 2, 3 and 4 with sampling frequencies of 100 Hz, 
12 Hz, 3 Hz, and 0.04 Hz, correspondingly. More details concerning the 
satellite instrument package are presented in file equipm.txt.

   The data of the experiments on board of Cosmos-1809 satellite can 
be used for the fundamental researches of the following near Earth 
physics issues:
- the ionosphere-magnetosphere coupling in different geophysical 
  conditions;
- global structure of the ionosphere and its modification caused by 
  solar and geomagnetic activity;
- strong earthquakes influence on the ionosphere and seismic precursors 
  in the ionosphere;
- nonlinear processes in the ionosphere plasma under impact of the 
  intensive radio waves;
- propagation of VLF and HF-emissions in the ionosphere and the 
  magnetosphere;
- diagnostic of the man-made impacts on the ionosphere.

   Raw satellite data are stored on magnetic tapes in the form of 
telemetry data. There is about 500 periods of measurements in the 
course of more than 6 years of the satellite operation (see file
catall.txt), the total data volume is about 7.5 Gbytes. The quality 
of tapes is far from perfect and data will be lost in near future.
   In the framework of data rescue project it is planned to process 
data for about 50 intervals during different anomaly events 
(earthquakes, active experiments including release of substance in the
ionosphere, heating of the ionosphere by HF waves at the Soura  
facility in Russia and so on). The list of selected orbits is presented 
in cat1.txt file. It is open for amendments.
   For these orbits the following physical parameters along the 
satellite path will be obtained:
1. Electron density and its irregularities;
2. Electron temperature;
3. DC electric field;
4. AC electromagnetic field of various frequencies.
   Approximate size of data set will be about 500 Mbytes and it is
planned to produce a CD. The software package attached to the CD will 
allow data selection and browse in MS-DOS operation system. Data output 
in the form of graphics will be included. 
   Samples of the satellite processed data are presented in files
fig1.exe - fig4.exe.

   Those interested in more details concerning Cosmos 1809 data should
address Dr. Yu. Romanovsky:
Institute of Applied Geophysics, Rostokonskaya str. 9,
129226 Moscow, Russia
fax: 7-095- 187-7513 or 181-0591
E-mail: geophys@sovamsu.sovusa.com or cengeo@glas.apc.org

                         Literature

1. Y. Romanovsky, D. Pulinets. The Availability of Data in the Former
   Soviet Union-Part3. Ionosonde. STEP International, 1993, v3, N3, p.4.
2. V. M. Kostin, Yu. A. Romanovsky, V. M. Chmyrev et al. Satellite
   Investigations of the Disturbances of the Outer Ionosphere Due to
   Modification of the Ionospheric F-region by High-Power HF Radio Waves.
   Cosmic Research, 1993, v31, N1, p.67 (A translation of Kosmischeskie
   issledovania).
3. S. I. Avdjushin, S. I. Kozlov, Yu. A. Romanovsky et al. "Active
   experiments and Antropogenic Effects in the Ionosphere." Cosmic
   Research, 1993, v31, N3, p.1.
4. S. A. Pulinets, Prospects of Topside Sounding, WITS handbook N2,
   Chapter 3, SCOSTEP Publishing, Urbana, Illions, p.99-127.
5. S. A. Pulinets, Russian satellite data base for use in ionospheric
   mapping, Procceedings of PRIME/URSI joint Workshop: Data validation of
   ionospheric models and maps, Roquetes, 1992, Publ. Abs. del Ebro, Mem.
   N16, p.105-110.
6. A. T. Karpachev and S. A. Pulinets, IRI model with topside sounding
   data in the light of Global longitudinal effect, Proceeding of
   PRIME/URSI joint Workshop: Data validation of ionospheric models and
   maps, Roquetes, 1992, Publ. Obs. del Ebro Mem. N16, p. 93-99.