Round-trip mission requirements for Asteroids 1976 AA and 1973 EC

The feasibility of manned or unmanned missions to two recently discovered asteroids is assessed. Characteristics of a likely target for a round-trip exploratory excursion include: a period close to one year; and an orbit that is nearly circular and nearly coplanar with the ecliptic. Mass requirements and optimal times of launch are investigated for unmanned and manned missions to Asteroids 1976 AA and 1973 EC (recently numbered 1943); 365-day round-trip trajectories in the first half of the 1990s are proposed. However, since neither of the two targets considered entirely fulfills all the necessary orbital characteristics, neither can offer the opportunity for a fast low-energy round-trip mission; nevertheless, other minor planets crossing earth's orbit may be found to meet the requirements.