Curiosity’s parachute passing flight-qualification testing in 2009 March and April. It’s inside the world’s largest wind tunnel at NASA Ames Research Center, Moffett Field, CA Photo credit: NASA/JPL-Caltech
In early September, the Sky Crane will gently place the Mars Science Laboratory (MSL) rover “Curiosity” In the red planet’s Gale Crater. But before the MSL can land, a Disk-Band-Gap (DGB) parachute must slow the precious cargo down to subsonic speeds.
The state-of-art Sky Crane is probably the most intricate, sophisticated and precise landing system ever sent to Mars, but its DGB parachute has a history of nearly 50 years of success.
Most recently, the Viking landers, Mars Pathfinder rover, both MER rovers and the Mars Phoenix lander relied on this type of parachute for a successful landing on the planet.
The MSL relies on the DGB parachute for atmospheric drag. The main disk–the D in DGB–is a dome-shaped canopy with a hole in the top that relieves air pressure. A gap (G) below the canopy releases air to prevent the canopy from tearing. A fabric band (B) under the gap increases lateral stability by controlling the direction of incoming air.
The first DGB was tested in 1967. It was launched from Walker Air Force Base in Roswell, New Mexico in a 26,000,000 foot cubed balloon and took three hours to reach an altitude of 130,000 feet above the White Sands Missile Range. The environment provided an adequate simulation of the atmosphere in Mars’s upper atmosphere.
The chute performed successfully, despite a tear in 2 of the 72 sections comprising the canopy.
To enable the use of a lighter-weight fabric and to reduce fabric stress, NASA reconfigured the original 72-sectioned canopy tested in 1967 to consist of 80 sections.
Red Planet, here we come!
Discovery News June 19, 2012