"The future comes slowly."
Low-Density Supersonic Decelerator (LDSD)
-- Johann Friedrich von Schiller, 18th century German historian and poet
As NASA plans ambitious new robotic missions to Mars, laying the groundwork for even more complex human science expeditions to come, the spacecraft needed to land safely on the red planet's surface necessarily becomes increasingly massive, hauling larger payloads to accommodate extended stays on the Martian surface. NASA has used its current, parachute-based deceleration system since the Viking Program
, which put two landers on Mars in 1977. New technology is needed to slow larger, heavier landers from the supersonic speeds of atmospheric entry to subsonic ground-approach speeds.
NASA seeks to use atmospheric drag as a solution, saving rocket engines and fuel for final maneuvers and landing procedures. The heavier planetary landers of tomorrow, however, will require much larger drag devices than any now in use to slow them down -- and those next-generation drag devices will need to be deployed at higher supersonic speeds to safely land vehicle, crew and cargo. NASA's Low Density Supersonic Decelerator (LDSD) Technology Demonstration Mission, led by NASA's NASA's Jet Propulsion Laboratory
in Pasadena, Calif., will conduct full-scale, stratospheric tests of these breakthrough technologies high above Earth to prove their value for future missions to Mars.
Three devices will be developed. The first two are supersonic inflatable aerodynamic decelerators -- very large, durable, balloon-like pressure vessels that inflate around the entry vehicle and slow it from Mach 3.5 or greater to Mach 2. These decelerators are being developed in 6-meter-diameter and 9-meter-diameter configurations. Also in development is a 30-meter-diameter parachute that will further slow the entry vehicle from Mach 2 to subsonic speeds. All three devices will be the largest of their kind ever flown at speeds several times greater than the speed of sound.
Together, these new drag devices can increase payload delivery to the surface of Mars from our current capability of 1.5 metric tons to 2 to 3 metric tons, depending on which inflatable decelerator is used in combination with the parachute. They will increase available landing altitudes by 2-3 kilometers, increasing the accessible surface area we can explore. They also will improve landing accuracy from a margin of 10 kilometers to just 3 kilometers. All these factors will increase the capabilities and robustness of robotic and human explorers on Mars.
To thoroughly test the system, the LDSD team will fly the drag devices several times -- at full scale and at supersonic speeds -- high in Earth’s stratosphere, simulating entry into the atmosphere of Mars. The investigators will conduct design verification tests of parachutes and supersonic inflatable aerodynamic decelerators in 2012 and 2013. The first supersonic flight tests are set for 2013 and 2014. Once tested, the devices will enable missions that maximize the capability of current launch vehicles, and could be used in Mars missions launching as early as 2018.
LDSD: Key Mission Facts
- To safely land heavier spacecraft on Mars, we need to open up bigger parachutes and other kinds of drag devices at supersonic speeds.
- High in Earth's stratosphere, NASA's Low Density Supersonic Decelerator mission will test new, full-scale parachutes and drag devices at supersonic speeds to refine them for future use at Mars. Testing will be conducted from 2012 through 2014, with potential launch to Mars as early as 2018.
- Current Mars landing techniques date back to NASA's Viking mission, which put two landers on Mars in 1977. That mission's parachute design has been in use ever since -- and will be used again in 2012 to deliver the Curiosity rover to Mars. To conduct advanced exploration missions in the future, however, NASA must advance the technology to a new level of sophistication.
- These new drag devices are one of the first steps on the technology path to landing humans, habitats and return rockets safely on Mars.