“Driving on the moon is like driving on ice,” warns Jeff Vogt, the advanced director for vehicle dynamics at General Motors. “If you can imagine the worst ice storm ever, that is what it is like.”
In order to prepare for my time behind the wheel of GM's lunar rover simulator, which promised to essentially realize a dream of mine since I was a child watching the Apollo astronauts, I was questioning Vogt.
Gene Cernan and Jack Schmitt, members of the Apollo 17 crew, combed the surface in search of geologically important rocks. Their quest was made more fruitful by their dependable 4×4. However, since Cernan and Schmitt launched their lunar lander from the moon in the ascent stage in December 1972, the idea of driving an off-road vehicle across the moon's pitted surface has been dormant.
The original manufacturer of Lunar Roving Vehicles, General Motors, now plans to make a comeback with a new Lunar Mobility Vehicle (LMV) in collaboration with Lockheed Martin.
GM's simulator, which enables engineers to test concepts for a vehicle that cannot be physically tested in a realistic manner on Earth, is a crucial development tool in this initiative. This is due to the moon's gravity, which is just one-sixth as strong as Earth's. The LMV's traction on the sandy surface is so bad because it has the same 1,500 kilos of mass as it does on Earth, but only one-sixth the weight.
I take the simulator's steering wheel. Avoiding sudden movements is the goal. No abrupt turns, starts, or pauses. Take it carefully when driving out of craters, advises Vogt. “We learned pretty quickly that if you accelerate too hard to climb an incline, with lower gravity, you launch into space.”
It turns out that the LMV is wonderfully gentle and responsive when driven slowly, like you would on ice. The biggest difficulty is a result of driving in a simulator where a 2D screen represents reality. There is very little feeling of inclination, like you would experience in reality if you were travelling up or down a crater, despite its 270-degree wrap-around image of the one square kilometer of the lunar south pole that is loaded into GM's computer.
When using the simulation, you are enclosed in a 26-foot-diameter high-definition display that is located in a dimly lit space. Driving the lunar program makes the majority of this motion undetectable because to the moderate driving motions. You operate the vehicle from the cockpit part, which is situated atop a pedestal that tilts side to side and pitches fore and aft. When the newest Corvette is being simulated, the ride must presumably become a little harsher.
You can tell you're rising when the LMV responds to the accelerator pedal in an abnormally lethargic manner. You are traveling downhill when it doesn't appear to slow down when you let off the throttle.
Large features are correctly depicted despite the limited quality of the South Pole imagery that is currently available. Based on knowledge of their frequency on the moon, smaller craters and rocks were produced statistically. The LMV demonstrates that it has sufficient ground clearance by effortlessly straddling the seemingly little pebbles. I have no clue how big they are in actuality, but I now know that the majority of the rocks the rover will meet can be driven straight over.
Although the LMV's peak speed is 25 kph, I never go faster than 12 kph. Although a simulated collision would be innocuous, the time required to restart the simulator would put an immediate stop to my moon driving fantasies. Although the Apollo LRV had a peak speed of 13 kph, astronauts typically drove at a speed of 5 kph to avoid damaging the rover and to reduce the amount of dust that its wheels generated.
Modeling the LMV's capabilities is crucial since, in contrast to the Apollo LRV, the LMV is anticipated to spend the majority of its time traveling independently between assignments while transporting live personnel. Remote piloting is not feasible due to the 3-second radio signal round-trip time from Earth, especially at the speeds the LMV is capable of.
In order for the LMV to function while the astronauts are not there, GM is transferring its expertise from its Cruise autonomous car division to it. Of contrast to the LRV, which stowed away with the astronauts during their voyage, the LMV will be delivered to the Moon's surface by a specialized lander in Lockheed Martin's design.
With autonomy, the LMV may start functioning as soon as it touches down, investigating the surrounding area and carrying out tests without having to wait for the astronauts from the Artemis lunar mission to arrive.
The Ultium electric drivetrain components used in GM's terrestrial EVs will also be used in the LMV. The Ultium battery cells used thus far in the GMC Hummer EV we previously tested and the upcoming Cadillac Lyriq are pouch-style prismatic cells, but GM's Ultium road map also contains the cylindrical cells the LMV will employ. Both vehicles will use the same electric motors. The business claims that these cylinder-shaped batteries, which resemble AA batteries, are better adapted to the dramatic 500-degree temperature changes that occur between the Moon's two weeks of sunshine and two weeks of darkness.
The programming for the LMV's four motors was influenced by GM's expertise from the control programs for the three electric motors in the Hummer EV. By directing power to the outside wheels, the motors will be able to make the most of the meager traction that is now available while also enabling the rover to perform cool maneuvers similar to the really tight bends the Hummer is capable of.
The two astronauts are seated in the LMV front of the front wheels rather than in the centre of the vehicle as they were in the LRV, which is one of the LMV's design features to take note of. By doing this, they are exposed to less of the abrasive dust that the front wheels are producing, which is less likely to attach to them due to its electrostatic charge.
The astronauts are seated openly in the models that GM designers show me, but they clarify that the most recent iterations include body panels that cover the seats and the LMV's cargo bed to help further block the dust.
It's made all the simpler to volunteer for the mission to drive the LMV on the moon knowing that GM has taken such precautions to assist preserve my future spacesuit in excellent condition. Who else has already practiced?
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