For the Mars Perseverance Mission, Motors is desperate

Perseverance, NASA’s fifth rover to study Mars, is currently moving around the region near its landing site in the Crater Jezero on Mars and using his drone helicopter to get a better view of his surroundings. Like many of his previous moves, he looks for water and signs of a past life, or at least signs of the right environmental conditions for him in the past. They are also collecting ground and rock samples with the goal of placing 30 of them in ships that will be lifted and returned to Earth on NASA’s future trip to Mars.

The main assemblies on the rover rely on 17 motors from maxon precision motors, inc. to fulfill their parts of the mission. For example, they are used to move the robotic arm that moves geological samples from one station to the next on the rover. Some motors will later be used to seal the sample vessels and place them on the surface of Mars, while the drone also relies on six maxon motors for steering.

NASA engineers selected maxon motors based on their experience using more than 100 other motors from the Swiss company on earlier rovers. The experts at NASA’s Jet Propulsion Lab (JPL) worked with maxon designers to modify and test motors outside of the company’s standard catalog.

The Perseverance rover and the Ingenuity drone explore the surface of Mars.

Most of the changes revolve around the environmental conditions that the motors will be exposed to when it launches and a 290-million-mile journey through space, in addition to its two-year mission. on the unstable surface of Mars. Some of these conditions include:

  • Shock and shock from the rocket launch, as well as atmospheric entry, takeoff and landing on Mars.
  • Vacuum during a trip to Mars and Martian atmosphere once it lands.
  • Radiation during a trip and once on Mars.
  • Daily temperatures between −184 ° F and 68 ° F (−120 ° to 20 ° C).

“As required, we changed the design of the cars and gearbox, said Robin Phillips, a maxon engineer who worked closely with JPL. “We have made substantial changes, ranging from aluminum or bronze industry standards for component to stainless steel or titanium for Mars motors. This allows engineers to match expansion coefficients for the different parts.

“We’ve also changed the way we repair parts together, from adhesives – the standard – to welding,” adds Phillips. “We also added a number of new components, such as securing rings to strengthen the links. ”

To ensure that the design and components of the rover would withstand mission conditions, maxon would simulate these conditions and introduce the new motors to them. “To test for vacuum resistance, we placed the motors in an empty chamber filled with 8 mbar of CO2 (about 1% of Earth’s normal weight) instead of setting an empty space, ”says Phillips. “We then applied different loads and ran the motors through the required performance profiles.

“We also used shakers and shock generators to simulate the vibrations and shocks from launching, and low temperature chambers to enable the motors to handle the day to day temperature changes. ”He adds.

The rover uses nine modified EC 32 horizontal drivers (right) from maxon and an EC 20 flatbed driver with a 22 UP GP gear head, all from maxon.  Six DCX 10 motors (left) move the swashplate on the drone which controls the tilt of the rotor blades.The rover uses nine modified EC 32 horizontal drivers (right) from maxon and an EC 20 flatbed driver with a 22 UP GP gear head, all from maxon. Six DCX 10 motors (left) move the swashplate on the drone which controls the tilt of the rotor blades.

The temperature signals were important to the drone motors because they are mounted outside the housing, which is kept warm by the batteries to keep the electronics working. The motors, however, feel full of frigid nights.

“All of this gave us confidence that if we built the drone’s motors in the same way as the motors that survived the certification tests, they would work,” Phillips explains. “As they say in the space industry, test what you fly and fly what you test. ‘”

Maxon new test facilities have invested over the past 10 years working with NASA on their Martian programs also used in commercial applications. The shock and vibration test lags, for example, are used to test air and car outputs. And the hollow chambers were critical to developing new welding methods for titanium.

The robotic arm of the rover (with the orange connections) moves and transports geological samples, as well as being loaded into ships that will receive a future Mars mission back and return to Earth.The robotic arm of the rover (with the orange connections) moves and transports geological samples, as well as being loaded into ships that will receive a future Mars mission back and return to Earth.

Unlike steel, titanium must be welded without the presence of oxygen. maxon uses titanium in space applications for its low strength and mass. The company also uses it in medical applications such as portable motors because it is unstable, which makes it biodegradable. The first example was a time maxon “borrowed” their titanium welding equipment from the space programs to develop a motor that helps maintain the blood flow of heart patients.

Space applications make up a small portion of maxon orders, but the stringent requirements are pushing the company to performance. This is reflected in the higher quality standards – as well as new testing methods – which are also beneficial to customers in other areas, such as medical technology. “Apart from this, such space missions are very interesting,” said Eugen Elmiger, Maxon Group CEO. “Over and over again, I am honored and proud that our missions are being used in these innovative Mars missions.”

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