The US Space Agency NASA successfully landed its fifth terrestrial rover on Mars on Thursday evening.
Perseverance – a highly-advanced 3-metre long robotic vehicle weighing more than a tonne – will scour the Red Planet’s surface for signs of ancient life and collect rock and soil samples for return to Earth.
Its landing came almost seven months after launching onboard the Atlas V-541 rocket from Cape Canaveral Air Force Station in Florida.
Mission control at NASA’s Jet Propulsion Laboratory kept watch as computers and sensors onboard the rover’s cruise and descent stages, as well as other spacecraft around Mars transmitted data on the progress of the Entry, Descent, and Landing (EDL) phase of the mission.
During this time, the team had to endure a so-called “seven minutes of terror” during which the descending spacecraft with the rover performs a sequence of risky actions that happens faster than signals can reach Earth.
How it happened
At an altitude of around 130 kilometres above Mars, the heat-protective carbon fibre aeroshell capsule carrying the rover entered Mars’s atmosphere.
The heat shield’s surface reached a peak temperature of 1,300 degrees celsius upon descent.
After slowing down to a speed of 1,600 kilometres per hour, a 21.5-metre wide supersonic parachute was deployed to slow the craft down.
However, because of Mars’s thinner atmosphere, this would not be enough to stop the rover from hitting the ground at an excessive speed.
At 20 seconds after parachute deployment, the capsule shed its heat shield, allowing the exposed rover to scan the terrain below for features which it could compare to an onboard map provided by engineers which included the safest landing sites.
Still travelling at around 300km/h, the craft then cut off the parachute and released its back shell, before an eight engine jetpack attached above the rover fired up its thrusters.
It swerved to avoid the falling shell and parachute and then continued its descent using sophisticated programming, before lowering Perseverance to the ground using cables – a manoeuvre dubbed as the Skycrane.
The rover hit the ground at a speed of 1.2km/h.
The team erupted in cheers after operations lead Swati Mohan confirmed touchdown at around 22:55 South African time.
It should be noted that this was actually more than 10 minutes after the rover had landed, due to the delay in communication caused by the great distance to Mars.
The images below show illustrations of what the entry, descent, and landing may have looked like.
After its landing, the rover captured three images using its onboard rear right hazard-avoidance camera.
The first image’s transmission appears to have been corrupted, but the other two showed clear imagery of the ground and several rocks in the vicinity of the rover.
Subsequent photos are expected to be of much greater quality as these will be taken with cameras that were still protected during the landing.
Below are two of three images Perseverance sent back to earth shortly after landing.