Earth Planets Space, Vol. 50 (No. 3), pp. 213-221, 1998
Takayuki Ono1, Hiroshi Oya1, Akira Morioka1, Atsushi Kumamoto1, Kaori Kobayashi2, Takahiro Obara3, and Tomoko Nakagawa4
1Department of Astronomy and Geophysics, Tohoku University, Sendai 980-8578, Japan
2Toyama Prefectural University, Kosugi, Toyama 939-03, Japan
3Communications Research Laboratory, Hitachinaka-shi, Ibaraki 311-12, Japan
4Tohoku Institute of Technology, Sendai 982, Japan
(Received September 24, 1997; Revised December 5, 1997; Accepted December 10, 1997)
Abstract: For the purpose of observing the Martian ionosphere under the condition of direct interaction with the solar wind by using a RF sounder together with a plasma density probe and high frequency plasma wave detectors, the Plasma Waves and Sounder (PWS) system onboard the Planet-B Mars orbiter has been developed through a proto-model (PM) which are followed 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 length of 52 m. The high power (600 Watts) transmitter of the sounder experiment 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 102 to 106/cc with a time resolution of 25 msec corresponding to a range resolution of 3.75 km. Observations of natural plasma waves and planetary radio waves in the frequency range from 20 kHz to 5 MHz are planned in the passive mode operation of the PWS system, identifying all the polarization characteristics together; observations of natural plasma waves caused by the direct interaction of the Martian ionosphere with the solar wind plasma are also a major purpose of the PWS experiment. For these purposes, a wide dynamic range and high sensitivity characteristics of the PWS receiver have been achieved. As the extended function of the PWS plasma sounder instrument, altitude measurement also will be carried out.