LDSD

LDSD (LDSD-1) [NASA]

LDSD in flight (artist impression) [NASA]

The LDSD (Low-Density Supersonic Decelerator) is a test vehicle led by NASA's Jet Propulsion Laboratory in Pasadena, Calif., to try out new techniques for entering the Martian atmosphere and decelerating the landing craft. LDSD consists of a balloon launched rocket vehicle, which is powered by a Star-48B rocket motor to propell the demonstrator through the stratosphere at supersonic speed.

After liftoff, the balloon carrying the LDSD test vehicle will slowly float upward, taking several hours to reach an altitude of 36,600 meters. At that point, the balloon will release the vehicle and its rocket will kick in, boosting the craft to an altitude of 54,900 meters.

When the test vehicle reaches 54,900 meters and is traveling at about Mach 3.8, it will deploy the first of the new technologies, a doughnut-shaped tube called the Supersonic Inflatable Aerodynamic Decelerator (SIAD). The SIAD decelerates the test vehicle to approximately Mach 2.5. The test vehicle will then deploy a mammoth parachute (the Supersonic Disk Sail Parachute), which will carry it safely to a controlled water impact about 40 minutes after being dropped from the balloon.

Three flights are planned with the first one testing mainly the performance of the vehicle. On the maiden flight, the parachute failed. The second flight used a redesigned parachute, which also failed.