PLASMA-WAVES AND SOUNDER (PWS) EXPERIMENT ONBOARD THE PLANET-B MARS ORBITER

For the purpose of observing the Martian ionosphere under the conditio n of direct interaction with the solar wind by using a RF sounder toge ther with a plasma density probe and high frequency plasma wave detect ors, the Plasma Waves and Sounder (PWS) system onboard the Planet-B Ma rs orbiter has been developed through a proto-model (PM) which are fol lowed by achievement of a flight-model (FM) for the Planet-B mission. The operation of the achieved system has been tested for function and stability in a simulated space environment. The PWS system is equipped with two sets of long deployable dipole antennas with a tip-to-tip le ngth of 52 m. The high power (600 Watts) transmitter of the sounder ex periment makes it possible to measure the electron density profiles of the Martian topside ionosphere in an altitude range from 300 to 3000 km in a density range from 10(2) to 10(6)/cc with a time resolution of 25 mu sec corresponding to a range resolution of 3.75 km. Observation s of natural plasma waves and planetary radio waves in the frequency r ange from 20 kHz to 5 MHz are planned in the passive mode operation of the PWS system, identifying all the polarization characteristics toge ther; observations of natural plasma waves caused by the direct intera ction of the Martian ionosphere with the solar wind plasma are also a major purpose of the PWS experiment. For these purposes, a wide dynami c range and high sensitivity characteristics of the PWS receiver have been achieved. As the extended function of the PWS plasma sounder inst rument, altitude measurement also will be carried out.