Mars 2020 landing timeline: From 12,500 mph to wheels down

Entry, descent and landing phase AKA ‘the seven minutes of terror’

NASA’s Mars rover Perseverance is set to complete its most dangerous part of the mission Thursday as it barrels through the Martian atmosphere and plops down on the red planet.
NASA’s Mars rover Perseverance is set to complete its most dangerous part of the mission Thursday as it barrels through the Martian atmosphere and plops down on the red planet.

NASA’s Mars rover Perseverance is set to complete its most dangerous part of the mission Thursday as it barrels through the Martian atmosphere and plops down on the red planet.

After launching from Cape Canaveral Space Force Station in July, the spacecraft with the rover is approaching Mars at around 112,000 mph. The arrival is known as the entry, descent and landing sequence and includes a complicated series of steps to bring the rover down to the ground at about 1.5 mph.

Formidable challenges will present themselves in the form of sand, boulders and impact craters near the target landing area called Jezero Crater, a 3.5 billion-year-old lake bed.

[MORE COVERAGE: Watch live, get updates as NASA lands a rover, helicopter duo on Mars today]

The landing is set to happen around 3:55 p.m. ET but in the 15 minutes leading up to Percy’s arrival on the red planet, a lot needs to go right for that to happen.

You can actually experience this along with the rover in this NASA simulation.

Here’s a breakdown of the timeline leading up to a successful arrival on Mars for NASA’s Mars 2020 rover:

3:38 p.m. Cruise separation stage

There is a reason NASA engineers refer to minutes leading up to landing on Mars as “seven minutes of terror.” The spacecraft carrying Mars 2020 will hit the Martian atmosphere traveling at over 12,500 mph using its thrusters to steer toward its landing target. At this point, the spacecraft will kick off its Cruise Stage shell, which includes solar panels, sensors and fuel that helped get Perseverance from Earth to Mars.

3:39 p.m. De-Spin

About a minute later, the spacecraft uses its thrusters to stop spinning and position itself for entry. At this point, the spacecraft is still traveling well over 10,500 mph.

3:40 p.m. Cruise balance masses ejected

Just over 30 seconds later, as the spacecraft is about 1,900 miles from the landing site on Mars, it drops two 154-pound balance masses, creating the right lift-to-drag ratio as it enters the Martian atmosphere about five minutes later.

3:48 p.m. Martian entry

A NASA illustration of the spacecraft containing NASA’s Perseverance rover slowing down using the drag generated by its motion in the Martian atmosphere. (Image: NASA) (WKMG 2020)

Now just under 400 miles from the landing site at Jezero Crater, the spacecraft carrying the rover will enter the Martian atmosphere, causing it to slow down but heat up, which is where its heat shield comes into play.

3:49 p.m. Guidance with the help of thrusters

Traveling at 11,988 mph coming down through the Martian atmosphere, the spacecraft will use its thrusters to keep it on course as it hits pockets of air, potentially throwing it off course.

3:50 p.m. Alignment

Just under five minutes to touchdown, the autonomous entry system will correct any remaining alignment errors.

3:52 Straighten up and fly right

That’s NASA’s term for this next phase as the spacecraft is now down to 1,068 mph. It will eject six more balance masses approximately 13 miles from the landing site.

3:52 p.m. Parachute deploy

A lot happens in the next three minutes to slow down for landing. First up, the spacecraft’s 70-foot diameter parachute deploys while still traveling almost twice the speed of sound.

But as NASA Mars 2020 entry, descent and landing lead Allen Chen explained on Jan. 27, “the parachute alone isn’t enough to slow down Perseverance for landing. In fact, the spacecraft is still going more than 160 miles per hour.”

3:52:39 p.m. Heat shield separation

This NASA illustration shows when Perseverance gets its first look at the Martian surface below, after dropping its heat shield just under six minutes after entry into the Mars atmosphere. (Image: NASA) (WKMG 2020)

Just 20 seconds later, the spacecraft heat shield pops off and drops away, exposing Perseverance to the atmosphere. At this point, the rover’s camera, microphones and other instruments will begin recording.

Chen explained when the heat shield protecting the rover jettisons away and that’s when NASA’s new radar and navigation system will kick in.

3:53 p.m. Terrain Relative Navigation begins and landing selection

This animation depicts the Terrain-Relative Navigation technique incorporated into entry, descent, and landing for the Mars 2020 rover. By taking images of the surface during its descent, the rover can quickly determine whether its headed toward an area of its landing zone that the mission team has determined is hazardous. If necessary, a divert maneuver can send it toward safer terrain.

Still traveling at about 200 mph and less than 3 miles from the landing site, the rover’s navigation system will help the spacecraft change course if needed based on live pictures taken of the ground. These pictures and maps will help the spacecraft know if it needs to change direction.

During the last mile of descent, Perseverance will fire up its engines, flying to a safe landing spot identified by its Terrain Relative Navigation system, known as the rover’s eyes and ears, and slow it down to about 1.5 mph.

3:54 p.m. Backshell separation

Less than one minute to touch down, the rover’s rocket-powered descent engines detach and begin flying above Mars.

3:54:45 p.m. Descent stage

This is it. The rover has 69 feet to descend to the ground using its descent stage to reduce speeds to less than 2 mph.

3:54:48 p.m. Rover separation

How NASA rover Perseverance will try to land on Mars

The rover drops from the descent stage and is lowered using 20-foot cables. This is what is also known as the sky-crane. As the rover separates, its wheels deploy for landing.

3:55 p.m. Touchdown

The rover lands on its wheels and the sky-crane flies away and crash lands away from the rover. At this point, the rover is officially on the red planet.

About 11 seconds after the work begins for the Perseverance rover on Mars, the rover has a helicopter named Ingenuity strapped to its belly that will deploy shortly after a safe landing on the red planet.

Follow updates on News 6 and ClickOrlando.com/space on Feb. 18 as NASA lands the Perseverance rover on the red planet.