This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
When I was a kid, I spent an awful lot of time and money on model rockets. I loved the whole process—picking out which Estes rocket kit to buy, carefully assembling the thing, and, most important of all, igniting a solid-fuel engine to shoot a high-velocity projectile into the sky. The problem was, I would often get to enjoy only one or two launches before the rocket crash-landed or, more often, drifted so far during its parachuted return that my friends and I couldn't find it. I always lamented that there was no way to control where the rocket went—you just glued the fins on as straight as you could, launched when the wind was mellow, and hoped for the best.
Hoping for the best isn't quite good enough when you move from the world of model rockets to real interplanetary missions, though. So engineers are constantly working to devise better descent and landing systems. (The Mars-bound Curiosity rover may have the most elaborate landing scheme ever.) Some landers use airbags, some use parachutes, and some use retrorockets to lower the craft to the surface. The video below shows an example of the latter approach—a rocket-powered descent, controlled by a computerized guidance system that flies the craft after liftoff.
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The video, filmed February 2 at the Mojave Air and Space Port in California, documents a test of the Xombie, a rocket built by Masten Space Systems that runs on isopropyl alcohol and liquid oxygen. The test was the first successful free flight of the Xombie under the control of Draper Laboratory's autonomous GENIE flight system (short for Guidance Embedded Navigator Integration Environment). In the test, the Xombie lifts off from one launch pad, rises to an altitude of 50 meters, hovers there before flying sideways 50 meters, and then lowers itself to a controlled landing on another pad. Needless to say, the 10-year old rocketeer in me is very impressed.