The Japanese Mars explorer NOZOMI was launched in July 1998. It was planed to arrive at Mars in October 1999. But a problem occurred when it left from the earth to Mars and it will reach Mars at the beginning of 2004. NOZOMI has several issues in its orbit determination, such as the spin modulation, the solar radiation pressure, the small force related to the attitude change, and the solar conjunction. We tried to solve these issues by using range and Doppler data. Recently, however, much more difficult problem has occurred. That is that the range and/or Doppler data cannot be obtained for some periods because we cannot turn the high gain antenna toward the earth due to the attitude constraint. Therefore we considered the orbit determination by using the Delta-VLBI method. In this paper, we summarize the issues of the orbit of NOZOMI up to now and show our recent activities on Delta-VLBI observations for NOZOMI.
|Number of pages||18|
|Journal||Advances in the Astronautical Sciences|
|Publication status||Published - 2003|
ASJC Scopus subject areas
- Aerospace Engineering
- Space and Planetary Science