The Low-Density Supersonic Decelerator or LDSD is a

reentry vehicle Atmospheric entry is the movement of an object from outer space into and through the gases of an atmosphere of a planet, dwarf planet, or natural satellite. There are two main types of atmospheric entry: ''uncontrolled entry'', such as the entr ...

designed to test techniques for

atmospheric entry Atmospheric entry is the movement of an object from outer space into and through the gases of an atmosphere of a planet, dwarf planet, or natural satellite. There are two main types of atmospheric entry: ''uncontrolled entry'', such as the ent ...

Mars Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury (planet), Mercury. In the English language, Mars is named for the Mars (mythology), Roman god of war. Mars is a terr ...

. The disc-shaped LDSD uses an inflatable structure called the Supersonic Inflatable Aerodynamic Decelerator (SIAD), which is essentially a donut-shaped balloon, to create

atmospheric drag In fluid dynamics, drag (sometimes called air resistance, a type of friction, or fluid resistance, another type of friction or fluid friction) is a force acting opposite to the relative motion of any object moving with respect to a surrounding flu ...

in order to decelerate the vehicle before deploying a large supersonic parachute. The goal of the $230 m project is to develop a reentry system capable of landing 2- to 3-ton payloads on Mars, as opposed to the 1-ton limit of the currently used systems. The vehicle is being developed and tested by NASA's

Jet Propulsion Laboratory The Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center in the City of La Cañada Flintridge, California, United States. Founded in the 1930s by Caltech researchers, JPL is owned by NASA an ...

Mark Adler Mark Adler (born 1959) is an American software engineer. He is best known for his work in the field of data compression as the author of the Adler-32 checksum function, and a co-author together with Jean-loup Gailly of the zlib compression librar ...

is the project manager. The vehicle was tested in 2014 and 2015.

June 2014 test flight

The test flight took place on June 28, 2014, with the test vehicle launching from the United States Navy's

Pacific Missile Range Facility The Pacific Missile Range Facility, Barking Sands is a U.S. naval facility and airport located five nautical miles (9 km) northwest of the central business district of Kekaha, in Kauai County, Hawaii, United States. PMRF is the world's larg ...

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, Hawaiʻi, at 18:45 UTC (08:45 local). A high-altitude helium balloon, which when fully inflated has a volume of , lifted the vehicle to . The vehicle detached at 21:05 UTC (11:05 local), and four small, solid-fuel rocket motors spun up the vehicle to provide stability. A half second after spin-up, the vehicle's

Star 48B The Star 48 is the largest of a family of solid rocket motors used by many space propulsion and launch vehicle stages. It is used almost exclusively as an upper stage. It was developed primarily by Thiokol Propulsion and is now, after several me ...

solid-fuel motor ignited, powering the vehicle to Mach 4.32 and a peak altitude of . Immediately after rocket burn-out, four more rocket motors despun the vehicle. Upon slowing to Mach 4.08, the tube-shaped Supersonic Inflatable Aerodynamic Decelerator (SIAD-R configuration) deployed. SIAD is intended to increase atmospheric drag on the vehicle by increasing the surface area of its leading side, thus increasing the rate of deceleration. Upon slowing to Mach 2.54 (around 86 seconds after SIAD deployment), the Supersonic Disksail (SSDS) parachute was deployed to slow the vehicle further. This parachute measures in diameter, twice the area of the one used for the

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mission. However, it began tearing apart after deployment, and the vehicle impacted the Pacific Ocean at 21:35 UTC (11:35 local) travelling . All hardware and

data recorder A data logger (also datalogger or data recorder) is an electronic device that records data over time or about location either with a built-in instrument or sensor or via external instruments and sensors. Increasingly, but not entirely, they a ...

s were recovered. Despite the parachute incident, the mission was declared a success; the primary goal was proving the flight worthiness of the test vehicle, while SIAD and SSDS were secondary experiments.

2015 test flights

A second test flight of LDSD took place in June 2015, at the Pacific Missile Range Facility. This test focused on the SIAD-R and Supersonic Ringsail (SSRS) technologies, incorporating lessons learned during the 2014 test. Changes planned for the parachute included a rounder shape and structural reinforcement. After several weather-related scrubs, the flight occurred on June 8. As in the first test, the SIAD structure inflated successfully but the parachute was damaged during deployment, this time after 600 ms and at drag.

After 2015

A 3rd test was expected in 2016, after some smaller scale tests with

sounding rocket A sounding rocket or rocketsonde, sometimes called a research rocket or a suborbital rocket, is an instrument-carrying rocket designed to take measurements and perform scientific experiments during its sub-orbital flight. The rockets are used to ...

s.''How to Land a House on Mars'' Feb 2016
/ref> The parachute team are hoping

Mars 2020 Mars 2020 is a Mars rover mission forming part of NASA's Mars Exploration Program that includes the rover ''Perseverance'', the small robotic, coaxial helicopter '' Ingenuity'', and associated delivery vehicles. Mars 2020 was launched from Ear ...

will have a camera on the parachute deployment and opening in 2021.

Gallery

File:Low Density Supersonic Decelerator (LDSD ) - 33.5-meter Supersonic Ring Sail Parachute.jpg, 33.5-meter Supersonic Ring Sail Parachute File:Low Density Supersonic Decelerator (LDSD ) - 6-meter SIAD-R.jpg, 6-meter SIAD-R File:Low Density Supersonic Decelerator (LDSD ) - 8-meter SIAD-E.jpg, 8-meter SIAD-E

References

External links

{{Commons category, Low-Density Supersonic Decelerator
LDSD project websiteLDSD fact sheet
NASA programs Spaceflight technology Exploration of Mars Articles containing video clips Inflatable aircraft