A few hours ago a prototype of a new NASA system called Low-Density Supersonic Decelerator (LDSD) which will be used to land vehicles that might be very heavy on Mars completed its first real test. A big balloon brought the prototype in the stratosphere, at an altitude of about 36,600 meters high (120,000 feet), over the Pacific Ocean. There, it was released for the test, which had only partial success due to a problem with the parachute.