1/22/2024 0 Comments Mars ingenuity helicopter![]() ![]() ![]() 17 (with data coming down no earlier than Saturday morning), the short hop would have Ingenuity take off, climb to 16 feet (5 meters), perform a small translation (sideways move), and then land again. This would be our 14 th flight and (hopefully) a relatively boring one compared to any of our more recent flights, where we flew long distances to acquire images of interest for the Perseverance rover team. If all goes well, we will follow this with a short test flight at a slightly lower rotor speed of 2,700 rpm. We will begin by performing a high-speed spin of the rotor without leaving the ground, reaching a peak rotor speed of 2,800 rpm (more than a 10% increase relative to our prior Mars experience of 2,537 rpm). This is not something we take lightly, which is why our next operations on Mars will be focused on carefully testing out higher rotor speeds in preparation for future flights. In fact, they will have to spin faster than we have ever attempted with Ingenuity or any of our test helicopters on Earth. Thankfully, there is a way to tackle this issue – but it involves spinning the rotors even faster than we have been doing up to now. But if the atmospheric density were to drop to 0.012 kg/m 3 in the coming months, our helicopter’s thrust margin could drop to as low as 8%, which means that Ingenuity would be operating close to aerodynamic stall (a condition where further increases in the blade’s angle of attack does not produce more lift, only more drag). That additional thrust is needed on takeoffs and climbs, during maneuvers, and also when tracking terrain with varying height. ![]() Thrust margin refers to the excess thrust that Ingenuity can produce above and beyond what is required to hover. At our lower design limit for atmospheric density (0.0145 kg/m 3), we know that Ingenuity has a thrust margin of at least 30%. The difference may seem small, but it has a significant impact on Ingenuity’s ability to fly. In the coming months we may see densities as low as 0.012 kg/m 3 (1.0% of Earth’s density) during the afternoon hours that are preferable for flight. With Ingenuity in its sixth month of operation, however, we have entered a season where the densities in Jezero Crater are dropping to even lower levels. We therefore prepared for flights at atmospheric densities between 0.0145 and 0.0185 kg/m 3, which is equivalent to 1.2-1.5% of Earth’s atmospheric density at sea level. When we designed and tested Ingenuity on Earth, we expected Ingenuity’s five-flight mission to be completed within the first few months after Perseverance’s landing in February 2021. ![]() But in one important way it is actually getting more difficult every day: I’m talking about the atmospheric density, which was already extremely low and is now dropping further due to seasonal variations on Mars. With the benefit of the knowledge acquired, conducting flights on Mars has in most ways become easier than it was at the outset. We have explored Ingenuity’s strengths and limitations in detail, leveraging the former and working around the latter to operationalize it as a highly capable reconnaissance platform. In the months since we flew for the first time, we have learned a great deal about operating a helicopter on Mars. ![]()
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