After six months of travel from Earth, the InSight spacecraft is on a precise trajectory to land on the red planet.
About three hours before landing, mission navigators will have a final chance to adjust InSight’s timing or alignment to avoid any perilous Martian dust storms.
Before InSight enters the Martian atmosphere, the spacecraft will split away from its solar-paneled cruise stage and switch to battery power.
Light and communications take 8 minutes and 7 seconds to reach Mars from Earth, so we won't know whether InSight’s landing was a success or failure until it’s over.
InSight will enter the thin Martian atmosphere at about 12,300 miles per hour.
The spacecraft must hit at an angle of 12 degrees to survive. Too steep and InSight will burn up; too shallow and it will skip across the atmosphere and back into space.
InSight will slow down quickly as it tears through the Martian atmosphere, then pop a supersonic parachute about seven miles above the surface.
A burst of pyrotechnics will release InSight’s heat shield, newly scarred from the heat of entry. The shield is thicker than on previous missions, in case InSight is forced to descend through heavy dust.
Ten seconds later, more pyrotechnics will extend the spacecraft’s three shock-absorbing legs. After that, InSight will turn on its ground-sensing radar.
Less than a minute before landing, InSight will drop and gain some distance from its parachute and back shell by freefalling for a moment.
The lander will fire 12 small rockets to slow down and move farther away from the falling parachute.
After stopping its horizontal motion, InSight will begin a smooth descent of about eight feet per second.
NASA expects to receive confirmation of landing on Monday at about 2:53 p.m. Eastern Time.
If InSight touches down successfully, it will be the first Mars landing since the Curiosity rover's complex landing in 2012.
InSight is aiming for a broad equatorial plain called Elysium Planitia.
The plain could make for boring pictures, but it is considered an ideal landing spot for a mission to study the planet’s interior.
After waiting several minutes for dust kicked up by landing to disperse, InSight will unfurl its two solar panels.
The lander will then spend a couple days checking its systems and taking images of the landing site.
In the days and weeks after landing, InSight will take stock of its surroundings, precisely measure and photograph the area around the lander and then use its robotic arm to carefully place three instruments on the Martian surface.
An exquisitely precise seismometer under a protective dome will listen for marsquakes and a burrowing heat probe will measure the inner temperatures of the planet.
The Curiosity rover touched down in August 2012 in Gale Crater, about 340 miles south of InSight’s planned landing site.
Curiosity is visible as a small dot inside the dark landing patch above, where bright surface dust was blown away during landing.
InSight’s design borrows heavily from the successful Phoenix mission, which touched down near the Martian north pole in 2008.
An orbiting spacecraft photographed Phoenix and its parachute descending in front of Heimdal crater, above.
In 2016, the Schiaparelli lander crashed into Mars after conflicting estimates of its altitude caused it to drop from its heat shield too early.
And in 2003, the Beagle 2 lander touched down successfully but was unable to communicate with Earth after it failed to deploy all of its solar panels.
Beagle 2 is the small white dot at center in the image above.
Mars has an elliptical orbit that brings it close to Earth every two years. InSight’s launch was timed to this window to minimize travel time.
May 5, 2018
May 5, 2018
May 5, 2018
InSight’s journey to Mars was relatively quick, compared with other missions that launched in 2018. The BepiColombo spacecraft will take seven years to reach Mercury and the Parker Solar Probe will spend seven years spiraling inward to touch the sun.
Sources: NASA; Jet Propulsion Laboratory; Caltech. Updated time estimates from the Planetary Society, though exact times will depend on landing conditions. Images by NASA/JPL-Caltech except where noted.