Keldysh Institute of Applied Mathematics, Moscow, Russia
The problem of sample return from ''relic bodies'' (asteroids and comets) is of great scientific value. Fine analysis of isotope soil composition, definition of isotopic scarcity relative to the Sun substance is of fundamental significance in the exploration of the Solar system. Similar analysis is possible only in the Earth conditions. It could present a standard to make a calibration of rough analysis, obtained by other space vehicles. The combination of both types of investigations is necessary to obtain reliable information on the structure and properties of primitive bodies. At present, it is not feasible to carry out the sample return from asteroids of the Main Belt with the help of conventional chemical launch vehicles of ''Proton'' type. The combination of Electric Propulsion with nuclear reactor of ''Topaz'' type and chemical engines makes possible to solve this problem. Escape velocity (V =2.5-3.5 km/s) can be achieved, when a high thrust engine is used,i.e. a final rocket stage. A low thrust engine is applied to fly to asteroid. High thrust is necessary for the landing of an independent lander on the asteroid. Then it can independently return to the Earth. A return vehicle separates an entry module near the Earth. In the Earth rendezvous it is not necessary to equalize the velocity as the excess velocity can be reduced by the deceleration in the Earth atmosphere. It was supposed that Fortuna-19 (''C''-type asteroid of the nearest part of the Main Belt) sample return mission is the most interesting problem. Mission to Fortuna-19 asteroid was considered according to the flight scheme: descending of a lander to take a soil sample and independent return of a lander to the Earth. There were considered launch epochs within time interval from 1999 to 2001 year. Total mission time is less than 4 years.Launch window in 1999 is preferable for the flight from the Earth to Fortuna, and 2003 is preferred date for the return flight. The 2001 launch window turns out to be the best if we exclude prolonged asteroid tracking. In case of remote intake of asteroid sample it is feasible to take it from two asteroids during one mission. When nuclear power reactor is used, the mission with two asteroids tracking can continue about 4 years. It is necessary to have 1-2 years more to return the samples from asteroids to the Earth. So, the mission is possible with rendezvous and sample intake from two asteroids. There were considered also the interplanetary missions with the use of EP to the planets, which are difficult for achievement and exploration - such as Mercury and Pluto - with rendezvous and landing of scientific equipment onto their surface. Investigation is worked out in collaboration with Russian-German Joint Study Group to prove a concept on the use of EP for the program of Solar System Exploration post-2000.