NASA’s new Mars rover, Perseverance, nears completion as it is fitted with new wheels and a massive air brake parachute.
The rover had its wheels fitted for the first time last year, but those were engineering model wheels which are used for fitting and testing, such as checking whether the rover could stand on its own wheels and take its own weight. With that testing now complete, the NASA team could remove the model wheels and replace them with the real wheels that the rover will run on when it reaches Mars.
Three of the six flight wheels that will travel to Mars can be seen attached to NASA’s Perseverance rover (which is inverted on a handling fixture) on March 30, 2020 at the Kennedy Space Center in Florida. The protective antistatic foil covering the wheels will be removed before launch this summer. NASA
Perseverance has slightly different wheels than NASA’s other Mars rover, Curiosity. Perseverance’s wheels are slightly larger in diameter, at 52.6 centimeters (20.7 inches) versus 50.8 centimeters, and are also slightly narrower. Curiosity’s wheels have 24 widely spaced treads in a chevron pattern, which prevents the rover from slipping sideways as it moves across unstable surfaces like sand as it climbs up the winding path of Mount Sharp.
Perseverance, on the other hand, has wheels with 48 gently curved treads that are spaced closely together, which NASA engineers have found give the same amount of grip as the chevron pattern but can better withstand pressure from sharp rocks. Curiosity has had issues with small breaks in some of its wheels, and although the wheels should still work for the lifetime of the rover, the newer design should prevent this kind of wear and tear.
A new parachute
In addition to the wheels, the rover has also had another vital component integrated: Its parachute, which will slow the rover’s descent onto Mars and help it touch down onto the planet’s surface gently without damaging any of the delicate components. The Perseverance rover will be the heaviest payload ever deployed on Mars, so the parachute canopy made of nylon, Technora, and Kevlar fiber needs to be very large — 70.5 feet wide — to slow the full weight of 2260 pounds of the rover from Mach 1.7 to 200 mph.
Launch of the rover is scheduled for between July 17 and August 5 this year.