Nowhere on Earth can we absolutely replicate the circumstances on Mars. Particular services can re-create sure parts with sufficient constancy to check particular eventualities, however every is restricted, resulting in a plethora of platforms and eventualities required to span the circumstances of Mars. In our prior submit, “The Proper Stuff,” the main focus was utilizing Ingenuity on Mars to check our macro capabilities: flying larger and sooner, touchdown at varied speeds, and usually increasing the flight envelope to retire the related threat for future Martian rotorcraft. The holy grail, nonetheless, is knowing the microscale – not simply proving Ingenuity can fly sooner however understanding how it flies sooner.
To reply the query, the NASA JPL Ingenuity crew labored with our aerodynamics companions at NASA Ames to design, validate, and execute a Sys-ID take a look at marketing campaign. “Sys-ID” refers to a course of referred to as system identification, a data-driven technique for understanding the complicated conduct of a system by finding out how particular inputs influence the movement of the automobile.
On this case, a frequency sweep (sine wave with various frequency) was injected into the management enter to trigger microscopic “nodding” of the automobile in ahead flight. The aerospace trade has lengthy relied on these strategies to characterize complicated automobile dynamics and validate simulation fashions. The identical strategies have been used throughout floor testing of Ingenuity on Earth, however as beforehand famous, there was no complete take a look at atmosphere on Earth to conduct full system testing like conventional Earth rotorcraft endure.
Through the early phases of the mission, the required dynamic maneuvers have been considered as too dangerous to carry out in-flight on Mars. As Ingenuity entered its third 12 months of operations and neared the top of its capacity to increase the flight envelope, the dangers of Sys-ID turned smaller and simpler to justify. In late 2023, a three-month effort was spent to develop, take a look at, and uplink a brand new software program model that linked parts of Ingenuity’s software program that have been used for Earth-based Sys-ID testing with the code that controls the automobile when flying horizontally.
This animation reveals a simulation of the response of NASA’s Ingenuity Mars Helicopter to the system identification, or “Sys-ID,” course of.
Credit: NASA/Ames.
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Animation depicts management enter that leads to microscopic “nodding” of the automobile in ahead flight.
The chance to conduct a Sys-ID flight was present in December 2023. Circumstances have been very best inside the decrease part of Neretva Vallis (believed to be an previous river valley) because of the terrain being almost as flat as on the crater flooring. Moreover, the mission schedule allowed for a break from the common flights wanted to remain forward of the rover because it was conducting a scientific loop by means of Gnaraloo Bay. Two devoted flights (Flights 68 and 69) have been executed that efficiently demonstrated the Sys-ID technique in-flight and, for the primary time on one other planet, characterised the automobile’s flight dynamics.
These flights prioritized amassing information in high-speed ahead flight circumstances – each inside and past Earth-based testing to correlate and prolong our data. The significance of that is highlighted by Allen Ruan, Ames aeromechanics flight dynamicist, “Getting the information from these two flights, particularly on the excessive ahead flight speeds, closes the loop on prior years of simulation and floor testing and informs us on enhancements for dynamics modeling and estimation of future Martian rotorcraft.”
The explanation that these flights are so important is as a result of they supply key basic validation of rotorcraft fashions and strategies which might in any other case require circumstances which can be inconceivable to copy right here on Earth. As defined by Tove Aagren, lead simulator at Ames and designer of the Sys-ID marketing campaign, “An inherent problem of working with Mars rotorcraft is that of mannequin validation. Extraterrestrial flight necessitates excessive confidence in our prediction fashions, but replicating the true flight situation to realize this confidence throughout a complete flight envelope in Earth-based testing is extremely non-trivial. To today, elements of ahead flight dynamics of Ingenuity stay related to uncertainty. That is what makes the chance to characterize key automobile dynamics within the true working situation, i.e. on Mars, extremely thrilling. Not just for the novelty of the strategy, however for the elemental insights that we actually can’t achieve in some other approach than by means of designated system identification flights.”
With a view to execute any such maneuver, Ingenuity needed to fly a report distance on the beforehand examined max groundspeed of 10 m/s (22.3 mph). An out-and-back flight with Sys-ID segments in every leg assured that for an anticipated east-west wind course at the least one leg is into the wind enabling testing at an airspeed better than 10 m/s. Getting two flights’ price of knowledge at these excessive speeds supplies a treasure trove that permits the crew to extend confidence within the conduct of future rotorcraft at Mars.
Moreover, now that these Sys-ID strategies have been demonstrated efficiently, a course of has been established that may be replicated for characterizing future flight autos earlier of their mission. This may higher outline the automobile’s efficiency, permitting the operations crew to plan with fewer unknowns and will allow future rotorcraft to be examined on Earth to satisfy solely the minimal functionality wanted to finish the mission, after which validated to larger ranges of efficiency after touchdown.
With in-flight system identification full, Ingenuity adopted within the footsteps of numerous legends, take a look at pilots who first pushed the boundaries of aerial flight, then house flight, and now Martian flight.
