Potential future Mars missions

Abstract

NASA has been intensively re-planning the future content of its Mars Program. The process has been inclusive with ideas being solicited and received from a broad spectrum of the community. Two synthesis workshops were held with inputs from numerous g'roups, including the leads of a wide variety of mission concepts that were studied in the last few months. The concepts are divided into five categories: Orbiters (with a specific example of a Reconnaissance Orbiter); Large Landers and Sample Return (discussing the features of second generation landers and how they could support a sample return mission); In Situ Concepts (with two examples: Multi-Scout and a Mars Stratigraphy Mission); Small Missions (Scouts and Micromissions); and Telecommunications. NASA's replanning process is not complete. Hence, this paper contains just a sampling of the many potential future Mars missions. INTRODUCTION During the summer and fall of 2000, NASA has intensively been re-planning the future content of its Mars Program. This activity was brought about by the loss of both Mars Climate Orbiter and Mars Polar Lander in the last quarter of 1999. Part of the process has been to solicit ideas and study a wide variety of missions for consideration in the future program. The new plan is not complete. Hence what we present here is a sampling of some of the many potential mission options that have been studied in recent months. The inclusion of a particular mission concept in this paper does not imply that it is more likely to be included in NASA's new plan than other concepts not described here. Throughout this paper, reference will be made to opportunities to launch to Mars. This term derives from the trajectories from Earth to Mars that are the most efficient in terms of required energy for ballistic Copyright © 2000 by the American Institute of Aeronautics and Astronautics, Inc. The U.S. Government has a royaltyfree license to exercise all rights under the copyright claimed herein for Governmental Purposes. All other rights are reserved by the copyright owner. transfers. These trajectories are classified as Type I, II, III, IV, etc., according to whether the flight angle of the transit is less than 180°, between 180° and 360°, between 360° and 540°, etc. A given trajectory type (e.g., Type I) occurs on average about every 26 months, according to the relative geometry between Earth and Mars. This periodicity defines the opportunities to launch to Mars, e.g., 2001, 2003, 2005, etc. Trajectory Types I and II have the desirable feature of the shortest flight times, typically in the range of six months to one year. Unless there is an overriding reason, these trajectory types will be used for spacecraft with chemical propulsion. All of the mission concepts described in this paper assume that the spacecraft are chemically propelled. However some missions studied employ solar electric propulsion, in particular for spacecraft returning samples from Mars back to Earth. BACKGROUND A year ago, the architecture of the Mars Program, at least through the 2005 opportunity, was wellestablished. Mars Global Surveyor was making discoveries that altered our most fundamental understanding of Mars and its history. After the two 1998/1999 missions, another orbiter and lander, already being assembled and tested, would be launched in 2001. Japan's orbiter Nozomi would arrive at Mars in 2003, the same year as the launch of Mars Express, an orbiter being developed by the European Space Agency. In addition, 2003 and 2005 would see launches of missions at the heart of the Mars Program, missions that would return samples of Martian rocks and soil to Earth for analysis. These missions would be carried out by a partnership between NASA and the French Space Agency, CNES. NASA would send a lander/rover in each of 2003 and 2005 to collect promising samples and loft them, in a sealed sample canister, into low Mars orbit. A French orbiter would capture one or both canisters, store them inside Earth entry probes, and return the probes to Earth. NASA would provide the capture equipment and the Earth entry probes. The French would also provide an Ariane 5 launch in 2005 for both their orbiter and NASA's lander. Their orbiter 1 American Institute of Aeronautics and Astronautics