Earth is the only planet in the solar system with aircraft capable of sustained flight. Suppose the ground-breaking Ingenuity helicopter, currently stowed aboard the similarly spectacular Mars Perseverance rover, accomplishes its planned mission. In that case, Mars will become the second planet to have a powered aircraft fly through its atmosphere.
Ingenuity has sent its first status report since landing on Mars. The signal, which arrived via the iconic Mars Reconnaissance Orbiter (MRO), reports on the state of the batteries of the helicopter as well as the operation of the base station, which, among other things, operates the critically important heaters that keep the electronics within an acceptable temperature range. Thankfully, it’s all good news for now, with the batteries and base station operating as expected.
While Ingenuity still hasn’t performed a flight yet (hopefully, this becomes an outdated statement soon), the helicopter has already overcome some daunting challenges. Perhaps the most perilous portion of Ingenuity’s journey was the interplanetary trip from Earth to Mars as part of the larger Perseverance rover mission. Launched in July of 2020, Perseverance touched down at Jezero Crater on Mars on February 18th. A new high-resolution video of the spectacular sky-crane landing of Perseverance was released by NASA earlier today and is mind-blowing all on its own.
It is easy to overlook how challenging landing on Mars is. The alarming fact of the matter is that only about half of Mars missions have made it successfully! One of the main reasons for this is the density of the Martian atmosphere. Thankfully, riding strapped to the belly of the rover, Ingenuity survived the perilous descent from space.
One of the most significant obstacles for landing on Mars will continue to present problems for our heroic helicopter now that it is safely on the surface. The atmospheric pressure on the surface of Mars is only about 1% that of Earth. To put that in perspective, the summit of Mount Everest has only one-third the atmospheric pressure of sea level. While this is thought to be at (or sadly in some cases beyond) the limit of what humans can survive, it is well beyond Earthbound helicopters’ range. If you’ve ever wondered why wealthy explorer-types don’t just cheat and take a helicopter to the summit of Everest, that’s why!
Compared to Mars, the air on Everest might as well be pea soup. The ridiculously rarefied air on Mars makes helicopter flight extraordinarily challenging. Ingenuity will spin its two counter-rotating rotors five times faster than Earthly helicopters, about forty times per second. Ingenuity is also light, only about 1.8 kilograms. The rotors are about 1.2 meters in diameter and are relatively oversized to maximize lift.
Mars does give Ingenuity a break in one area, thankfully. Mars has only about one-third of the surface gravity of the Earth. If you were to hold the aircraft while standing on the Earth, it would feel roughly as heavy as a two-liter bottle (with a couple of sips taken out for luck). On Mars, the exact same aircraft would feel like a 20 oz bottle (591 milliliters).
The helicopter does not play a critical role in the science mission of Perseverance. It is essentially a technological demonstration or proof-of-concept, and data collected from Ingenuity will be used in engineering future Martian aircraft. It is solar-powered and features electronics that have been miniaturized to keep everything light enough for flight.
Ingenuity is also fully autonomous. Due to the extreme distance of Mars, the helicopter mission controllers can’t fly the aircraft in realtime the way Earthly drone-pilots can use joysticks to maneuver at home. The time it takes for a signal to travel from Earth to Mars is longer than the helicopter’s entire flight-time! Imagine if you were driving a car (on a closed course in your imagination only), and when you turned the wheel, the car ran out of gas before it registered your input!
If Ingenuity successfully demonstrates powered aerodynamic flight on Mars, it will be a milestone unlike any that has come before. One can only imagine the impact that flying Mars explorers could have on future missions. A future helicopter could be partnered with a larger rover and act as a scout, carefully surveying the terrain and helping the parent rover more efficiently plot a safe and scientifically interesting course. Perhaps a helicopter could pick up samples from a wide area and deliver them to a rover or stationary facility with highly sophisticated scientific instrumentation. Even a standalone helicopter mission could be conceived. There are plenty of cliffs, ice caps, volcanoes, or otherwise inaccessible parts of the Martian landscape that are likely permanently beyond the reach of ground-based rovers or even humans.
The coming weeks will be one of the most exciting periods for fans of space exploration, aviation, or anybody who is stirred by extraordinary accomplishments in engineering and, of course, the ingenuity of the brilliant scientists and engineers that built Ingenuity.
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