NASA plans to crash land on Mars. Here's why

NASA's latest plans for a Mars lander, called SHIELD, will smash into the planet's surface rather than glide gracefully down to the ground.
Christopher McFadden
Artist's impression of the new NASA lander.
Artist's impression of the new NASA lander.

NASA 

NASA has announced its intentions to develop a new kind of Mars lander that can survive a crash landing rather than using the more sophisticated approaches used to date. They believe this should offer considerable savings for making future probes and landers to alien worlds.

So far, NASA has landed on Mars nine times without any problems using various methods, including cutting-edge parachutes, giant airbags, and jetpacks to land safely.

Now, engineers are trying to find out if crashing is the best way to land on Mars. This new crashable lander, Simplified High Impact Energy Landing Device, or SHIELD for short, would use an accordion-like, collapsible base that acts like a car's crumple zone absorbs the energy of a hard impact instead of slowing down a spacecraft's fast descent.

The new design could make it much cheaper to land on Mars by making the scary entry, descent, and landing process more accessible and giving people more options for where to land.

“We think we could go to more treacherous areas, where we wouldn’t want to risk trying to place a billion-dollar rover with our current landing systems,” explained SHIELD’s project manager, Lou Giersch of NASA’s Jet Propulsion Laboratory in Southern California in a press release.

“Maybe we could even land several of these at different difficult-to-access locations to build a network,” he added.

The new lander should probably more accurately be called a "crasher"

A lot of the design of SHIELD comes from NASA's Mars Sample Return project. The first step of that campaign is for the Perseverance rover to collect rock samples in airtight metal tubes. A future spacecraft will bring those samples back to Earth in a small capsule and safely crash land in a deserted area.

Velibor Ćormarkovic, a SHIELD team member at JPL, said that when engineers looked at different ways to do that process, they wondered if the general idea could be turned around.

“If you want to land something hard on Earth, why can’t you do it the other way around for Mars?” he said. “And if we can do a hard landing on Mars, we know SHIELD could work on planets or moons with denser atmospheres.”

Engineers had to show that SHIELD can protect sensitive electronics during landing in order to test the theory. The team at JPL used a drop tower to test how well the sample tubes on Perseverance would hold up in a hard landing on Earth.

This is almost 90 feet (27 meters) tall and has a giant sling called a "bow launch system" that can throw something into the ground at the same speed as a Mars landing.

NASA plans to crash land on Mars. Here's why
Image of the prototype lander's crashable base.

Ćormarković used to work in the auto industry, where he tested cars with crash dummies inside. In some of these tests, the cars are put on sleds that are sped up to a high speed and then crashed into a wall or something that bends. There are many ways to get the sleds moving faster, such as using a sling like the bow launch system.

“The tests we’ve done for SHIELD are kind of like a vertical version of the sled tests,” said Ćormarković. “But instead of a wall, the sudden stop is due to an impact into the ground.”

The new design has thus far proven very promising

On August 12, the team met at the drop tower with a full-size prototype of SHIELD's collapsible attenuator, which is an inverted pyramid of metal rings that absorb impact. They hung the attenuator from a grapple and put a smartphone, a radio, and an accelerometer inside to simulate the electronics a spacecraft would carry.

“Hearing the countdown gave me goosebumps,” said Nathan Barba, another SHIELD project member at JPL. “The whole team was excited to see if the objects inside the prototype would survive the impact,” he added,

In about 110 miles per hour, the bow launcher slammed SHIELD into the ground in just two seconds (177 kilometres per hour). This closely replicates the speed a Mars lander reaches close to the surface after being slowed by atmospheric drag from its initial speed of 14,500 miles per hour (23,335 kilometres per hour) when it enters the Mars atmosphere.

In previous SHIELD tests, the "landing zone" was just a patch of dirt. For this test, the team put a 2-inch-thick (5-centimeter-thick) steel plate on the ground to make a landing harder than one on Mars. The onboard accelerometer later showed that SHIELD was hit with about 1 million newtons of force, which is the same as 112 tonnes crashing into it.

NASA plans to crash land on Mars. Here's why
The drop tower used to test the base.

High-speed camera footage of the test shows that SHIELD hit at a slight angle, then bounced about 3.5 feet (1 metre) into the air before flipping over. The team thinks that the steel plate is to blame for the bounce, since there was no bounce in the previous tests.

When the team opened the prototype and took out the simulated electronic payload, they found that all of the devices on board, including the smartphone, were still working.

“The only hardware that was damaged were some plastic components we weren’t worried about,” Giersch said. “Overall, this test was a success!”

From here on out, the team will now work on designing the rest of the lander next year.

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