We watch as the drama unfolded of Perseverance’s entry, descent, and landing (EDL) – the riskiest portion of the rover’s mission that some engineers call the “seven minutes of terror” – live on NASA TV.
Below are the key milestones at the estimated times of the landing (Because of the distance the signals have to travel from Mars to Earth, these events actually take place on Mars 11 minutes, 22 seconds earlier than what is noted here.).
Cruise stage separation
The part of the spacecraft that has been flying Perseverance – with NASA’s Ingenuity Mars Helicopter attached to its belly – through space for the last six-and-a-half months will separate from the entry capsule at about 3:38 p.m. EST (12:38 p.m. PST).
Atmospheric entry
The spacecraft is expected to hit the top of the Martian atmosphere traveling at about 12,100 mph (19,500 kph) at 3:48 p.m. EST (12:48 p.m. PST).
Peak heating
Friction from the atmosphere will heat up the bottom of the spacecraft to temperatures as high as about 2,370 degrees Fahrenheit (about 1,300 degrees Celsius) at 3:49 p.m. EST (12:49 p.m. PST).
Parachute deployment
The spacecraft will deploy its parachute at supersonic speed at around 3:52 p.m. EST (12:52 p.m. PST). The exact deployment time is based on the new Range Trigger technology, which improves the precision of the spacecraft’s ability to hit a landing target.
Heatshield separation
The protective bottom of the entry capsule will detach about 20 seconds after the parachute deployment. This allows the rover to use radar to determine how far it is from the ground and employ its Terrain-Relative Navigation technology to find a safe landing site.
Backshell separation
The back half of the entry capsule that is fastened to the parachute will separate from the rover and its “jetpack” (known as the descent stage) at 3:54 p.m. EST (12:54 p.m. PST). The jetpack will use retrorockets to slow down and fly to the landing site.
Touchdown
The spacecraft’s descent stage, using the sky crane maneuver, will lower the rover down to the surface on nylon tethers. The rover is expected to touch down on the surface of Mars at human walking speed (about 1.7 mph, or 2.7 kph) at around 3:55 p.m. EST (12:55 p.m. PST).
A variety of factors can affect the precise timing of the milestones listed above, including properties of the Martian atmosphere that are hard to predict until the spacecraft actually flies through.
