Perseverance Mars rover gets its wheels as launch preps continue

The Perseverance Mars rover, positioned on its back in a clean room at the Kennedy Space Center in Florida, is now equipped with its six flight wheels, wrapped in protective foil, as processing continues amid coronavirus restrictions. Image: NASA/JPL-Caltech

Despite NASA-wide work slowdowns or stoppages due to coronavirus, work to ready the $2 billion Perseverance Mars rover for launch in July is continuing at the Kennedy Space Center.

Classified as an “essential” project by NASA management, Perseverance must take off between July 17 and Aug. 5, while Earth and Mars are in favourable orbital positions, or the flight will be delayed until 2022 when the next launch window opens. The rover is one of the few NASA projects that is continuing while the Kennedy Space Center is closed to all but essential personnel.

The 1,025-kilogram (2,260-pound) rover’s most recent additions include its huge braking parachute and six wheels, seen above wrapped in anti-static foil. The wheels were carved out of a block of flight-grade aluminium and feature titanium spokes. They were engineered to be tougher than the wheels used by the Curiosity rover, which have suffered major damage rolling over sharp rocks in the Sharp Crater landing zone.

The Perseverance rover’s wheels were engineered to be tougher than Curiosity’s, which have suffered extensive damage rolling over sharp rocks on Mars. Image: NASA/JPL-Caltech

Perseverance’s wheels are slightly larger than Curiosity’s and incorporate a different tread design. Instead of the 24 chevron-pattern treads used by Curiosity, the new wheels feature 48 gently curved treads intended to be more resistant to penetration while providing a firmer grip on the surface.

Attachment of the wheels came a few days after engineers stowed Perseverance’s tightly packed parachute in the spacecraft back shell where it will remain until the rover falls into the martian atmosphere on 18 February 2021. Deployed at an altitude 11 kilometres (seven miles), the parachute will inflate to a diameter of 21.5 metres (70.5 feet) in a half second, slowing the descending rover from nearly twice the speed of sound to about 320 kph (200 mph). Engineers say the 88-kilogram (194-pound) parachute is packed so tightly it has the density of oak.

Perseverance will land using same “sky crane” technology employed by Curiosity, dropping from the parachute and back shell for a rocket-powered final descent before being lowered to the surface on a long umbilical.