NASA is about to land its $830-million InSight mission on Mars. Here's a second-by-second timeline of the probe's treacherous journey to the Martian surface.

2:40 p.m. ET: The InSight lander, tucked inside an entry capsule, separates from the spacecraft that carried the mission to Mars.

2:41 p.m. ET: The entry capsule turns to orient itself for atmospheric entry at just the right angle — about 12 degrees relative to the surface.

2:47 p.m. ET: The capsule begins to plow through the first layers of the Martian atmosphere at about 12,300 mph.

2:49 p.m. ET: The spacecraft's protective heat shield reaches its maximum temperature of about 1,500 degrees Celsius. This is hot enough to melt steel.

15 seconds later: InSight slows down at its most rapid pace, and the intense heating may cause a temporary radio-communications blackout.

2:51 p.m. ET: InSight unfurls its supersonic parachute.

15 seconds later: Six explosive charges blow off the spacecraft's heat shield.

10 seconds later: InSight's three three legs pop out after pyrotechnic charges explode.

2:52 p.m. ET: A landing radar turns on to constantly measure InSight's distance to the ground.

2:53 p.m. ET: The first radar signals are received and processed, helping InSight tweak its approach to Mars.

20 seconds later: InSight detaches from its back shell and parachute and begins free-falling toward the ground

Half a second later: The lander's retrorockets (or descent engines) fire up.

2.5 seconds later: The falling robot uses its retrorockets to make a slight turn and orient for landing.

22 seconds later: The probe slows down to 5 mph.

2:54 p.m. ET: InSight safely reaches on the surface of Mars — NASA's first spacecraft to land on the red planet in six years.

3:01 p.m. ET: The first "I'm alive and well" signal beeps from InSight's radio system reach Earth

3:04 p.m. ET (though possibly many hours later): InSight takes its first photo on the surface of Mars.

8:35 p.m. ET: Confirmation from InSight via NASA's Mars Odyssey orbiter that InSight's solar arrays have deployed

You can watch NASA's live landing coverage below starting around 2 p.m. ET on Monday.