HAI HELI-EXPO is THE place to learn about the latest in rotorcraft technology, but this year’s attendees were briefed on an aircraft designed for a truly historic mission: the first extraterrestrial flight on Mars. Two representatives from NASA’s Jet Propulsion Laboratory (JPL) spoke Wednesday on the Mars Helicopter, which will be part of the Mars 2020 Rover mission.
Matt Muszynski, a NASA systems engineer, spoke first about the overall Mars 2020 mission. This mission, with a launch window of mid-July to early August 2020, is the 11th in a series of orbiters and rovers that have been sent to Mars since 2000.
A mobile scientific platform, the Mars Rover will carry a number of scientific instruments, including ground-penetrating radar, a weather station, multiple cameras, and a tool to convert carbon dioxide to oxygen. It will also carry a laser strong enough to incinerate rocks from a distance of 20 feet and a spectrometer to analyze their chemical composition.
Muszynski emphasized the challenges of operating an autonomous vehicle in a terrain with no roads and no tow trucks. Avoiding hazards is key, and simply becoming trapped in a sand dune could be catastrophic. Capturing an aerial perspective in a machine not limited by terrain would be immensely useful. But is it possible to fly a helicopter in a controlled manner in the Martian atmosphere? That’s what the Mars Helicopter, a technology demonstrator, is designed to find out.
Havard Grip, the Mars Helicopter flight control and aerodynamics lead, spoke next on the challenges of creating an aircraft to operate in Martian conditions. The Mars Helicopter has two coaxial rotors—a compact design that was chosen, Grip said, because it fit well into the available space in the belly of the Mars Rover, where the helicopter will stay during the launch and journey to Mars.
Because the Martian atmosphere is only 1% as dense as Earth’s, the rotors are designed to spin at speeds of 1,900 to 2,800 rpm. The large, lightweight rotors are made of foam core covered in a carbon-fiber skin and are much stiffer than conventional rotors.
The entire aircraft weighs 1.8 kg, or about 4 lbs. Below the rotor assembly sits a small box and four legs. Inside the temperature-controlled box are all the components that require protection from the cold Martian night, whose temperatures fall as low as -90 degrees Celsius (-130 degrees Fahrenheit).
Grip described the extensive testing necessary to understand the dynamics of the aircraft. Versions of the helicopter were tested in a large vacuum chamber at JPL that mirrored Martian environmental conditions. Grip did note, however, one environmental parameter that couldn’t be adjusted for the test: gravity (Mars’s gravity is only 38% of Earth’s).
The solar-powered aircraft will perform five test flights, each lasting 90 seconds, at a ground speed of 2 mps. Just like the Rover, all flights will be conducted autonomously, with flight control back on Earth uploading daily instructions. The results of the test flights will inform NASA’s investments in future technology.