NASA Jet Propulsion Laboratory (JPL) scientists on Wednesday presented a preview of the upcoming Mars 2020 mission that included a comprehensive account of the Mars Helicopter Scout (MHS) drone that will be deployed on the Red Planet. The mission is designed to help determine if life ever existed on Mars and also help prepare for humans coming to the planet by investigating available resources, NASA JPI systems engineer Matt Musynski told a packed room at Heli-Expo 2020.
The MHS is designed to test technology that could be used on future Mars missions to find interesting targets for study, as well as help plan the rover’s route. MHS is expected to fly no more than five times during its 30-day test campaign, which is slated for 2021. The flights will each last no more than three minutes at altitudes ranging from about 10 to 33 feet agl, with a maximum range of about 2,000 feet.
But before proceeding with building the drone, NASA engineers had to determine if controlled flight was even possible in the thin Martian air, which is only 1 percent of the earth’s atmospheric density, said Havard Grip, a member of the Mars 2020 Helicopter team. An additional challenge was to find the answer while in earth’s gravity.
The helicopter team built a full-scale mockup, but “we had to slim it down,” to get to its Martian weight. Engineers stripped all power, communication, and other equipment from the MHS and turned the test model into something of a "fly-by-wire" aircraft, with all power and flight control data it would produce when fully configured fed by a wire. Flights inside a test chamber proved the concept’s viability.
MHS also must withstand the g forces and vibration of launch, and incorporates radiation-resistant systems that can operate in the harsh Martian environment. Communication lags between the two planets precludes flights controlled from earth, so it will use autonomous control, and after each landing upload data to the Mars 2020 rover for transmission to earth.
With two contra-rotating carbon fiber blades some four feet in length, the four-pound MHS is equipped with a high-resolution, downward-looking camera for navigation, landing, and survey terrain.
As a compass is useless in the Red Planet’s inconsistent magnetic field, MHS will use a solar tracker camera integrated to a JPL visual-inertial navigation system to find its way, with additional inputs from gyros, visual odometry, tilt sensors, altimeter, and hazard detectors. Solar panels will recharge its batteries.
About 60 to 90 Martian days after landing, the rover will drop MHS from its underside and then drive away some 330 feet to avoid any dust kicked up from the rotor wash created by the force of the blades spinning from 1,900 rpm to 2,800 rpm—roughly three to six times the maximum rpm of a traditional helicopter.
Mars 2020 is scheduled to launch from Cape Canaveral, Florida, sometime between July 17 and August 5.