Mars

The second pending interplanetary ISAS mission is Planet-B, a Mars orbital mission due for launch in 1998 with arrival at the Red Planet in 1999. The primary goal of the 35-kg payload will be to study the interaction of the solar wind with Mars' atmosphere. Mars has a very weak magnetic field as compared with Earth and all other planets except Venus, thus it is suspected that the un obstructed solar wind strips away much of the Martian atmosphere. The spacecraft will weigh approximately 540 kg at launch with a bus diameter of 2.0 m. The spin-stabilized (7.5 rpm) Planet-B will also feature two solar arrays capable of producing up to 200 W in Mars orbit, a 5-m long mast, a 1.7-m long boom, and four wire antennas about 25 min length. Twelve principal instruments have been selected to measure the local particles and fields in addition to mapping the Martian surface from altitudes ranging from 150 km to 30,000 km (References 143-148).