InSight landed on Mars on Nov. 26, 2018 at 11:52:59 a.m. PT (2:52:59 p.m. ET). The entry, descent, and landing (EDL) phase began when the spacecraft reached the Martian atmosphere, about 80 miles (about 128 kilometers) above the surface, and ended with the lander safe and sound on the surface of Mars six minutes later.
For InSight, this phase included a combination of technologies inherited from past NASA Mars missions such as NASA’s Phoenix Mars Lander. This landing system weighed less than the airbags used for the twin rovers or the skycrane used by the Mars Science Laboratory. The lean landing hardware helped InSight place a higher ratio of science instruments to total launch mass on the surface of Mars.
Compared with Phoenix, though, InSight’s landing presented four added challenges:
- InSight entered the atmosphere at a lower velocity — 12,300 miles per hour (5.5 kilometers per second) vs. 12,500 miles per hour (5.6 kilometers per second).
- InSight had more mass entering the atmosphere — about 1,340 pounds (608 kilograms) vs. 1,263 pounds (573 kilograms).
- InSight landed at an elevation of about 4,900 feet (1.5 kilometers) higher than Phoenix did, so it had less atmosphere to use for deceleration.
- InSight landed during northern hemisphere autumn on Mars, when dust storms are known to have grown to global proportions in some prior years.
Some of the changes in InSight’s entry, descent and landing system, compared to the one used by Phoenix, are:
- InSight used a thicker heat shield, partly to handle the possibility of being sandblasted by a dust storm.
- InSight’s parachute suspension lines used stronger material.
The entry, descent and landing sequence breaks down into three parts:
- Entry – The spacecraft was controlled by small rockets during descent through the Martian atmosphere, toward the surface.
- Parachute Descent – The InSight spacecraft slowed using a large parachute, jettisoned its heat shield and extended its three shock-absorbing legs.
- Powered Descent – Once the lander separated from its backshell and parachute, 12 descent engines on the lander began firing and the onboard guidance software slowed down the spacecraft until touchdown.