Low-Density Supersonic Decelerator
Reentry vehicle testing Mars landing techniques with inflatable decelerators.
The Low-Density Supersonic Decelerator (LDSD) is a reentry vehicle developed and tested by NASA's Jet Propulsion Laboratory to test techniques for atmospheric entry on Mars. The disc-shaped vehicle uses an inflatable structure called the Supersonic Inflatable Aerodynamic Decelerator (SIAD), a donut-shaped balloon, to create drag and decelerate before deploying a large supersonic parachute. The project aims to develop a reentry system capable of landing 2- to 3-ton payloads on Mars, exceeding the current 1-ton limit.
Quick Facts
- Manufacturer
- Jet Propulsion Laboratory
- Country
- United States
- Operator
- NASA
- Applications
- Technology demonstrator
- Spacecraft Type
- Hypercone
- Launch Mass
- 3120 kg
- Dimensions
- Diameter: 15 ft
- Orbits
- Suborbital
- Built
- 3
- Orders
- 0
- Launched
- 2
- First
- 2014-06-28
Facts from the source article.
Lore & Background
A second test flight occurred on June 8, 2015, after weather-related scrubs. This test focused on the 6-meter SIAD-R and Supersonic Ringsail (SSRS) technologies, incorporating lessons from 2014, including a rounder parachute shape and structural reinforcement. The SIAD inflated successfully, but the parachute was damaged during deployment after 600 ms at 80,000 pounds drag. No third full-scale LDSD flight test was conducted after 2015. The parachute team wanted Mars 2020 to have a camera on parachute deployment and opening in 2021.
Reader's Guide
The Low-Density Supersonic Decelerator represents a critical step in advancing Mars entry, descent, and landing capabilities. By testing inflatable decelerators and large supersonic parachutes, the project addresses the challenge of landing heavier payloads—up to 2 to 3 tons—compared to the current 1-ton limit. Although both test flights experienced parachute failures, the SIAD performed successfully, demonstrating the viability of inflatable drag devices. The project's iterative approach, incorporating lessons from each test, underscores NASA's methodical development of technologies for future Mars missions. The LDSD's legacy includes informing parachute design for Mars 2020 and paving the way for larger payloads needed for human exploration.
Did You Know?
- The LDSD's SIAD is a donut-shaped balloon that inflates to 6 meters in diameter to increase atmospheric drag.
- The 2014 test flight used a high-altitude helium balloon with a volume of 975,000 cubic meters to lift the vehicle.
- The Supersonic Disksail parachute deployed in 2014 measured 30.5 meters in diameter, twice the area of the Mars Science Laboratory parachute.
- The 2015 test flight's parachute was damaged after 600 milliseconds at 80,000 pounds of drag.
Frequently Asked Questions
What is the Low-Density Supersonic Decelerator?
The LDSD is a disc-shaped reentry vehicle built by NASA's Jet Propulsion Laboratory to demonstrate new atmospheric entry techniques for Mars. It pairs an inflatable aerodynamic decelerator with a supersonic parachute to slow a craft during descent through the thin Martian atmosphere.
How does the LDSD actually slow a vehicle down on Mars?
It first inflates a donut-shaped balloon called the Supersonic Inflatable Aerodynamic Decelerator to generate drag, then deploys a large parachute engineered to function at supersonic speeds. This two-stage approach lets it shed velocity in the low-density Martian air where a conventional parachute would struggle.
Why do we need the LDSD if we already have Mars landers?
Current Mars landing systems cap out around a one-ton payload, which limits what can be delivered to the surface. The LDSD project targets a 2- to 3-ton capability, opening the door for heavier rovers, habitats, and cargo missions.
Where and when was the LDSD tested?
The vehicle was dropped from high-altitude aircraft over the U.S. Navy's Pacific Missile Range Facility on Kauaʻi, Hawaiʻi, during test campaigns in 2014 and 2015. Those flights simulated the high-speed, low-density conditions a Mars entry would face.
Who leads the LDSD project and how much did it cost?
NASA's Jet Propulsion Laboratory developed the system under project manager Mark Adler, with a total budget of roughly $230 million. It sits within the broader aerospace engineering and planetary entry systems field.
More in Exploration of Mars 1-24
Spotted an error? Know more?
Reader corrections go straight into our review queue. Suggest an edit · How this site is sourced