The Mars Aerial Platform mission - A global reconnaissance of the Red Planet using super-pressure balloons

The Mars Aerial Platform (MAP) mission is a conceptual design for a low-cost, Discovery class mission whose purpose would be to generate tens of thousands of very high resolution (20 cm/pixel) pictures of the Martian surface, map the global circulation of the Martian atmosphere, and examine the surface and sub-surface with ground penetrating radar, infrared spectroscopy, neutron spectroscopy, and other remote sensing techniques. The data would be acquired by instruments which are carried by balloons flying at a nominal altitude of about 7 km over the Martian surface. Because new balloon and micro-spacecraft technology is now available, the balloon probes could be quite long-lived, lasting hundreds or even thousands of days, producing an immense science harvest in the process. Together with the Mars Environmental Survey (MESUR) surface network science mission, MAP would revolutionize our knowledge of the Red Planet. Mission Descri ption The MAP mission will be carried out as follows: A lowcost launch vehicle such as a Delta 7925 (1000 kg TMI) is used to propel a small spacecraft carrying 8 entry capsules onto trans-Mars injection. Approaching Mars, a spinner is used 10 days prior to arrival to release the capsules outward so that they enter Mars' atmosphere at widely dispersed locations. Each capsule then enters the atmosphere, and deploys a parachute which slows it down to the point where a balloon can be inflated. The inflation is accomplished during descent, so that no landing system is required (the practicality of accomplishing this has been demonstrated on Earth at altitudes of up to 150,000 feet, where atmospheric density is similar to Mars). After the balloon is inflated, the parachute, capsule, and inflation equipment is jettisoned, and used to land a meteorology package consisting of pressure and temperature sensors, battery and transmitter on the surface. Each of the balloon probes will then commence their float around Mars at a altitude of about 7 km (23,000 ft) above the mean surface level. The probes, which will never land in the course of their long duration aerial cruise, will carry a gondola payload of 8 kg, which includes 2 cameras, 1 kg of atmospheric science and additional instruments, data recording and transmitting equipment, a rechargeable battery and solar array. When it is daylight two pictures are taken simultaneously every 15 minutes. One is taken with a high resolution CCD black and white camera with a nominal resolution of 20 cm per pixel; with a 1024 x 1024 pixel field, this gives a field of view 204 m on a side. The other is taken with a color camera at a moderate resolution of 10 m per pixel; this gives a field of view 10.2 km on a side. The two cameras are aligned so that the high resolution image is located at the center of the medium resolution picture, whose features in turn can be used to locate the region studied on a map of the planet. The data is stored and then is periodically uplinked to an orbiting satellite, which could either be Mars Observer or the MESUR comsat, and is then transmitted back to Earth. It is anticipated that the science return of this mission will be large, with 32,000 high resolution pictures returned to Earth for each 100 days of operation of an eight balloon fleet, plus an equal number of pictures at resolutions superior to the best Viking images. The high resolution pictures will have a factor of 7 greater resolution than the best pictures returned from Mars Observer. Additional science return will result from use of other instruments, such as a ground penetrating electromagnetic sounder. Tracking the balloons will yield knowledge of Mars' global atmospheric circulation. The cost of the mission is anticipated to be low, falling below the $150 million (without launch) ceiling of the Discovery-class guidelines. A mass breakdown for the mission is given in the tables below. As can be seen in fig. 1, each probe can be packaged in a 1.1 meter diameter aeroshell, and 8 such probes together with their carrier spacecraft can be fitted into the launch fairing of a single Delta.