InSight Lander Prepares for Harrowing Descent to the Surface of Mars
It's one tough parking job.
by Tiffany JeungDebuting the West Coast’s first interplanetary launch on May 5, NASA’s InSight lander embarked on a 54.6-million kilometer (about 33.9 million mile) trip to the Red Planet. Tasked with the unique mission of exploring the interior of Mars — during which it’ll deal with everything from Mars-quakes to internal heat flow — the lander needs to successfully complete a six-minute, white knuckle-inducing process before it can get to work: landing on Mars.
Distilled into eight main drawings, chief engineer Rob Manning from NASA’s Jet Propulsion Laboratory explains in a video just how rigorous the landing requirements are.
“It takes thousands of steps to go from the top of the atmosphere to the surface,” he says. “And each one of them has to work perfectly to be a successful mission.”
The Insane Precision of Entry, Descent, and Landing
Slated for November 26 around 3 p.m. Eastern, InSight begins the entry, descent, and landing process — EDL, for short — just before it first reaches the thin Martian atmosphere, which is located about 128 kilometers (or 80 miles) above the surface. Its process is similar to NASA’s strategy for Phoenix’s Mars landing in 2008, but with a few extra challenges, including higher mass and less atmosphere to slow it down. Fortunately, InSight has an extra decade of NASA wisdom and technology on its side.
Phoenix, NASA's 2008 lander, took many aerial selfies and stitched them together for this composite photo on the Martian surface.
Seven minutes before hitting the top of the atmosphere, InSight will first ditch its cruise stage, which is attached to the aeroshell that protects the lander itself. Then, it will reorient itself to enter Mars’ thin atmosphere, keeping its heat shield carefully angled at the atmosphere at a 12-degree angle as it zooms toward Mars at about 13,000 miles per hour.
“Any steeper, and the vehicle will hit the thicker part of the atmosphere and will melt and burn up,” Manning explains. “Any shallower, and the vehicle will bounce off the atmosphere of Mars.
The illustration shows the separation of the lander from the cruise stage. The lander, on right, is protected by the backshell.
Seventy miles above the surface of Mars, the air gets thicker as the temperature rises, taking the heat shield to temperatures over 1,000 degrees Celsius, which is hot enough to melt steel. The vehicle then has only two minutes to decelerate from 13,000 miles per hour to 1,000 miles per hour.
To reach subsonic speeds, the vehicle releases a parachute 10 miles above the surface. Fifteen seconds after that, it ejects the heat shield, allowing the lander to see the surface for itself. Ten seconds after letting go of the heat shield, three shock-absorbing legs emerge for landing. One minute later, the lander turns on its radar, calculating its height and speed. Once it’s just one mile above the surface, the lander finally releases its backshell and turns on its engines, dodging both the parachute and the backshell to prevent a collision.
The moment the lander finally reaches the surface, the engines must turn off immediately to prevent it from tipping over.
InSight will land a mere 373 miles (or 600 kilometers) from Curiosity.
The lander will aim for Elysium Planitia as a landing site, a plane affectionately called “the biggest parking lot on Mars.”
If completed successfully, InSight will finally dig in for the marathon of Martian research that lies ahead.
