Balloons Examine Distant Planets.

• Position: NASA's Jet Propulsion Laboratory - Brief Article

In the continuous quest to find cost-effective ways to explore the planets, NASA engineers have risen to the occasion by developing a variety of new methods inspired by centuries-old, solar-heated hot-air balloons, as well as by conventional helium light-gas balloons. For NASA, balloons are of considerable interest as a means of lowering spacecraft to a planet's surface, delivering instruments to various altitudes, and performing aerial photography and other forms of remote-sensing science. They can potentially conduct explorations faster and cover greater distances than conventional ground-based planetary explorers.

"Solar-heated balloons can descend more slowly than heavier parachutes to drop off a payload, and yet they can raise again after the drop-off. They offer us bonus science because they can take off repeatedly during daylight hours and land in hard-to-reach terrain," explains Jack Jones, technical monitor for balloon activities at NASA's Jet Propulsion Laboratory (JPL), Pasadena, Calif. "Our inspiration comes from the centuries-old Montgolfiere balloons named after the two French Montgolfier brothers who flew the first hot-air balloon by burning a pile of wool and old shoes in 1783."

Other balloons use ammonia, which evaporates with solar heat and causes inflation of the balloon. Helium balloons can...