The Mars Society Germany (Mars Society Deutschland e. V.) has made a sensational mission proposal to the German space agency DLR (Deutsches Zentrum für Luft- und Raumfahrt e. V.): the Mars Society Balloon Mission. The proposal was presented on February 14 and 15, 2001, at the Mars/BepiColombo Workshop at the DLR Center in Bonn. During this mission, a so-called super-pressure balloon would float for up to 100 days over the Martian surface and collect a vast quantity of scientific data, as well as unprecedented landscape photographs. Since Germany has never previously sent a probe to another planet, this would be the first German interplanetary mission.
The complete study is available at http://www.marssociety.de/projekte/balloon.html.
In contrast to proposals from industry in the past, this mission is very small, simple, and economical. This is achieved by the use of existing technology, as well as by a particularly simple mission design. During the design phase, several professors, Ph.D. recipients, engineers, and students of the Technical University of Munich collaborated with colleagues from ESA and NASA, who all belong to the Mars Society Germany. The design group included highly experienced members, such as Professor Ruppe, who has already collaborated with NASA on the Apollo Program. One motivation for this proposal was the dissatisfaction with the overall structure of Germany's space research. At the moment, too much money is spent for paper studies and too little is allocated for practical hands-on space projects. German space research and science suffer greatly from this spending distribution.
The balloon probe would be launched as a secondary payload on an Ariane 5 rocket; the primary payload could be a commercial satellite or another Mars probe. Accordingly, it is possible to launch without its own acceleration stage, which reduces the cost and weight. The mass at launch is then approximately 140 kg. The probe enters the Martian atmosphere directly (so-called "direct entry") and gets decelerated in the Martian atmosphere. Therefore, a braking stage is not required. Today's heat shield technologies can handle such a re-entry without problems. As an example, during the successful Mars Pathfinder mission, the probe entered the Martian atmosphere in the same way as it is planned for the balloon mission.
After the heat shield has slowed the probe, a parachute is deployed, which further slows the still-folded balloon to about 35 m/s. While hanging from the parachute, the balloon is slowly inflated. This is similar to the VEGA probes which were deployed in the atmosphere of Venus in 1985. As soon as the balloon is almost completely inflated, the parachute is released and the balloon levels out at the proper altitude.
The balloon then circles over the Northern hemisphere ten times during approximately 100 SOL (SOL means Martian day, which is approximately as long as one Earth day) before it runs out of hydrogen and slowly sinks to the ground.
In contrast to similar mission proposals by the French space agency CNES, no landing is planned for the Mars Society Balloon Mission. Additionally, we use an super-pressure balloon, which means that the balloon floats always at the same altitude - even at night - because it always holds its volume and therefore its density. The weather affects its flight altitude only slightly.
This mission offers not only the potential for fascinating pictures of unprecedented quality for the public, but also a fantastic opportunity for the planetary scientist to study the planet. After the publication of the mission proposal, we received several offers for scientific experiments on the balloon, such as a magnetometer, a high-resolution camera, and atmospheric measuring instruments. These suggestions can be implemented, since together they do not exceed the maximal payload of 2 kg. Some important questions could be clarified by these experiments, such as the geological past of Mars and whether there is water on Mars.
The costs of space missions can be estimated only from empirical values. We have therefore estimated the costs with the appropriate software and the experience of Professor Michael Bosch. The cost is an estimated maximum of 55 million Euro. This is the most reasonable Mars mission of all time without being inferior. During the mission length of 100 days so much data will be collected like never before.
Member of the Board
Mars Society Germany e. V.