posted 09-05-2021 11:13 AM               

With now 13 flights, and expanding flight durations, I got very curious about the battery system design and power requirements.

posted 09-20-2021 04:45 PM               

Flying on Mars Is Getting Harder and Harder

In the months since we flew for the first time, we have learned a great deal about operating a helicopter on Mars. 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.

Above: NASA’s Ingenuity Mars Helicopter acquired this image using its navigation camera during its 13th flight on Sep. 5, 2021 (Sol 193 of the Perseverance rover mission) at the local mean solar time of 12:06:30.. (NASA/JPL-Caltech)

With the benefit of the knowledge acquired, conducting flights on Mars has in most ways become easier than it was at the outset. 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.

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. We therefore prepared for flights at atmospheric densities between 0.0145 and 0.0185 kg/m3, which is equivalent to 1.2-1.5% of Earth's atmospheric density at sea level. 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. In the coming months we may see densities as low as 0.012 kg/m3 (1.0% of Earth's density) during the afternoon hours that are preferable for flight.

The difference may seem small, but it has a significant impact on Ingenuity's ability to fly. At our lower design limit for atmospheric density (0.0145 kg/m3), we know that Ingenuity has a thrust margin of at least 30%. Thrust margin refers to the excess thrust that Ingenuity can produce above and beyond what is required to hover. That additional thrust is needed on takeoffs and climbs, during maneuvers, and also when tracking terrain with varying height. But if the atmospheric density were to drop to 0.012 kg/m3 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).

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. In fact, they will have to spin faster than we have ever attempted with Ingenuity or any of our test helicopters on Earth. 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.

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). If all goes well, we will follow this with a short test flight at a slightly lower rotor speed of 2,700 rpm. This would be our 14th 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. Occurring no earlier than Friday, Sept. 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. And while the results from a Flight 14 should be less than riveting, the significant increase in available rpms (from 2,537 to 2,700) for future helicopter operations will provide us the option to perform scouting missions for Perseverance at lower atmospheric densities. It also leaves some wiggle room if we decide an additional rpm increase is needed later.

A speed increase like this comes with a number of potential issues. One of these has to do with aerodynamics: A rotor speed of 2,800 rpm, in combination with wind and helicopter motion, could cause the tips of the rotor blades to encounter the air at nearly 0.8 Mach – that is, 80% of the speed of sound on Mars. (The speed of sound on Mars is somewhat lower than we are used to – about ¾ the speed of sound on Earth.) If the blade tips get sufficiently close to the speed of sound, they will experience a very large increase in aerodynamic drag that would be prohibitive for flight. For Ingenuity's rotor we do not expect to encounter this phenomenon until even higher Mach numbers, but this has never been confirmed in testing on Earth.

Another potential issue is unknown resonances in the helicopter structure. Like all mechanical systems, Ingenuity has resonances that can lead to large vibrations when excited at particular frequencies. It is important to ensure that there are no significant resonances at the rotor speed used for flight, as this could cause damage to hardware and lead to a deterioration in sensor readings needed by the flight control system.

Additional demands will also be put on several components of Ingenuity's design: The motors will need to spin faster, the electrical system will need to deliver more power, and the entire rotor system will need to withstand the higher loads that come with increased rotor speeds. It all adds up to a significant challenge, but by approaching the issue slowly and methodically, we hope to fully check out the system at higher rotor speeds and enable Ingenuity to keep flying in the months ahead. Stay tuned for updates.

posted 09-28-2021 05:03 PM               

2,800 RPM Spin a Success, but Flight 14 Delayed to Post Conjunction

It's been an eventful several Martian days, or sols, since our last blog post, so we wanted to provide everyone with an update on where things stand on Mars. In our last post, we explained that we were getting ready to begin flying with a higher rotor speed to compensate for decreasing atmospheric density caused by seasonal changes on Mars. Increasing the rotor speed is a significant change to how we've been flying thus far, so we wanted to proceed forward carefully. Step one was to perform a high-speed spin test at 2,800 rpm on the ground and, if everything went well, step two was to perform a short-duration flight, briefly hovering over our current location, with a 2,700 rpm rotor speed.

Above: The upper swashplate of NASA's Ingenuity Mars Helicopter controls the pitch of the upper rotor blades as they rotate and is critical to stable, controlled flight. The swashplate is driven by three small servo motors. (NASA/JPL-Caltech)

The high-speed spin test was completed successfully on Sept. 15, 2021 at 23:29 PDT, 11:11 LMST local Mars time (Sol 204 of the Perseverance mission). Ingenuity's motors spun the rotors up to 2,800 rpm, briefly held that speed, and then spun the rotors back down to a stop, all exactly as sequenced for the test. All other subsystems performed flawlessly. Of particular interest was determining whether the higher rotor speeds cause resonances (vibrations) in Ingenuity's structure. Resonances are a common challenge in aerial rotorcraft and can cause problems with sensing and control, and can also lead to mechanical damage. Fortunately, the data from this latest high-speed spin showed no resonances at the higher rotor rpm's. The successful high-speed spin was an exciting achievement for Ingenuity and gave us the green light to proceed to a test flight with a 2,700 rpm rotor speed.

The test flight was scheduled to take place on Sept. 18, 2021 (Sol 206) and was supposed to be a brief hover flight at 16 feet (5 meters) altitude with a 2,700 rpm rotor speed. It turned out to be an uneventful flight, because Ingenuity decided to not take off. Here's what happened: Ingenuity detected an anomaly in two of the small flight-control servo motors (or simply "servos") during its automatic pre-flight checkout and did exactly what it was supposed to do: It canceled the flight.

Ingenuity controls its position and orientation during flight by adjusting the pitch of each of the four rotor blades as they spin around the mast. Blade pitch is adjusted through a swashplate mechanism, which is actuated by servos. Each rotor has its own independently controlled swashplate, and each swashplate is actuated by three servos, so Ingenuity has six servos in total. The servo motors are much smaller than the motors that spin the rotors, but they do a tremendous amount of work and are critical to stable, controlled flight. Because of their criticality, Ingenuity performs an automated check on the servos before every flight. This self-test drives the six servos through a sequence of steps over their range of motion and verifies that they reach their commanded positions after each step. We affectionately refer to the Ingenuity servo self-test as the "servo wiggle."

The data from the anomalous pre-flight servo wiggle shows that two of the upper rotor swashplate servos – servos 1 and 2 – began to oscillate with an amplitude of approximately 1 degree about their commanded positions just after the second step of the sequence. Ingenuity's software detected this oscillation and promptly canceled the self-test and flight.

Our team is still looking into the anomaly. To gather more data, we had Ingenuity execute additional servo wiggle tests during the past week, with one wiggle test on Sept. 21, 2021 (Sol 209) and one on Sept. 23, 2021 (Sol 211). Both of the wiggle tests ran successfully, so the issue isn't entirely repeatable.

One theory for what's happening is that moving parts in the servo gearboxes and swashplate linkages are beginning to show some wear now that Ingenuity has flown well over twice as many flights as originally planned (13 completed versus five planned). Wear in these moving parts would cause increased clearances and increased looseness, and could explain servo oscillation. Another theory is that the high-speed spin test left the upper rotor at a position that loads servos 1 and 2 in a unique, oscillation-inducing way that we haven't encountered before. We have a number of tools available for working through the anomaly and we're optimistic that we'll get past it and back to flying again soon.

Our team will have a few weeks of time to complete our analysis because Mars will be in solar conjunction until mid-October, and we won't be uplinking any command sequences to Ingenuity during that time. Conjunction is a special period in which Mars moves behind the Sun (as seen from Earth), making communications with spacecraft on Mars unreliable. Ingenuity will not be completely idle during this time, however; Ingenuity and Perseverance will be configured to keep each other company by communicating roughly once a week, with Ingenuity sending basic system health information to its base station on Perseverance. We will receive this data on Earth once we come out of conjunction, and will learn how Ingenuity performs over an extended period of relative inactivity on Mars. See you on the other side of conjunction!

posted 11-08-2021 08:19 PM               

Above: This is the first color image of the Martian surface taken by an aerial vehicle while it was aloft. (NASA/JPL-Caltech)

posted 11-18-2021 01:41 PM               

Video from the Mastcam-Z instrument aboard NASA's Perseverance Mars rover captures a closeup view of the 13th flight of the agency's Ingenuity Mars Helicopter, on Sept. 4, 2021.

posted 02-07-2022 10:10 PM               

In April 2021, under the direction of project manager MiMi Aung and the Mars Ingenuity Helicopter Team, a small robotic helicopter achieved the first powered flight on another planet. Delivered to the surface of Mars by the rover Perseverance, Ingenuity was a technology demonstration aboard the Mars 2020 mission and successfully proved that flight was possible on the Red Planet. It is also now serving as a helpful tool to aid rover exploration of Mars.

Ingenuity completed increasingly challenging flights and scouted areas for the Perseverance rover's upcoming treks. Total flight time for the Mars helicopter in 2021 topped 30 minutes over the course of 18 flights.

Ingenuity's "Wright brothers moment" captured the attention of the public back on planet Earth and inspired everyone to imagine what could be next in planetary exploration.

posted 03-13-2022 02:17 PM            

Ingenuity successfully completed its 21st flight on the Red Planet.

A mandate for a maximum of five "test" flights over one month; has now become an operational element of the mission.

posted 04-05-2022 04:27 PM               

The NASA/JPL Ingenuity Mars Helicopter Team Awarded the 2021 Robert J. Collier Trophy

The National Aeronautic Association (NAA) is pleased to announce that NASA's Jet Propulsion Laboratory (JPL) Ingenuity Mars Helicopter Team has been named the recipient of the 2021 Robert J. Collier Trophy for "...the first powered, controlled flight of an aircraft on another planet, thereby opening the skies of Mars and other worlds for future scientific discovery and exploration."

Since 1911, the Collier Trophy has been awarded annually for "...the greatest achievement in aeronautics or astronautics in America, with respect to improving the performance, efficiency, and safety of air or space vehicles, the value of which has been thoroughly demonstrated by actual use during the preceding year." The list of Collier recipients represents a timeline of air and space achievements, marking major milestones in the history of flight. The 525-pound bronze trophy is on permanent display at the Smithsonian's National Air and Space Museum in Washington, D.C.

"While NASA's Ingenuity Mars Helicopter team expanded the flight envelope by 100-million miles, we know we didn't do it alone," said Larry James, Interim-Director of NASA's Jet Propulsion Laboratory in Southern California. "For it was the efforts and ingenuity of those women and men who developed and tested cutting-edge vehicles before us that helped make powered-controlled flight on another planet possible. That our Mars Helicopter name will now appear on this iconic trophy alongside so many of these air and space giants is an honor, and fuels us to continue exploring the skies over the Red Planet."

One hundred and seventeen years after the Wright brothers succeeded in making the first powered flight on our planet, the Ingenuity Mars Helicopter performed this amazing feat on another world. On April 19, 2021, Ingenuity lifted off from the surface of Mars, climbed to the prescribed altitude of 10 feet, and maintained a stable hover for 30 seconds. It then descended, touching back down on the surface of Mars after logging a total of 39.1 seconds of flight, thereby becoming the first aircraft in history to make a powered-controlled flight on another planet.

Since its first flight, Ingenuity has accomplished all of its technology demonstration goals and successfully transitioned into service as a science scout for the Perseverance rover, investigating promising science targets and safe routes of travel for its companion and demonstrating the efficiency and safety benefits of the first multi-robot explorers on another planet. The helicopter's color camera has also been used to collect high-definition imagery to assist the science team in identification and assessment of intriguing, and in some cases previously unknown, geologic features. To date, the mission's official logbook has entries for 24 flights and a cumulative flight time of over 43 minutes.

The Ingenuity Mars Helicopter Team displayed exceptional creativity, perseverance, and dedication to advancing the state of the art in aeronautics and astronautics. The helicopter's flight dynamics and controls were invented from first principles due to the thin atmosphere on Mars and an entirely new kind of test program had to be developed from scratch. The result – a solar powered, counter-rotating, propeller-driven planetary aircraft that stands 22 inches tall, weighs just 4 pounds, and meets the stringent requirements of both spacecraft and aircraft.

"I recently travelled to Kitty Hawk, North Carolina, and was in awe to be able to stand where the Wrights achieved the first flight on our planet," said Bob Balaram, Chief Engineer emeritus and innovator of the Mars helicopter design. "It is my hope that, some day, when people travel to Mars' Jezero Crater that they consider visiting where the first flight on that world occurred!"

Simultaneously honoring the past and inspiring the future of aviation and space, the Ingenuity Mars Helicopter carries a small swatch from the left wing of the first Wright Flyer with it into the Martian skies on every flight. Ingenuity's success will make possible a new generation of solar system explorers that will scout the unpaved Martian road ahead, keeping human voyagers safe and informing our world of future discoveries.

"The challenges of autonomously flying a helicopter in the atmosphere of Mars cannot be overstated," expressed NAA Chairman, Jim Albaugh. "This accomplishment truly warrants and has earned this year's Collier Trophy."

NAA President, Greg Principato added, "Almost no one thought a helicopter could be flown on Mars. There were many who thought the project was not worth the effort. It is by overcoming such doubts that great achievements happen and that's what the Ingenuity Team did. It is our honor to present them with the 2021 Collier Trophy."

The Collier Trophy Selection Committee, comprised of 44 aviation and aerospace professionals, reviewed presentations from four nominees and selected the NASA/JPL Ingenuity Mars Helicopter Team as the recipient of the Collier Trophy on March 31, 2022.

The 2021 Collier Trophy will be formally presented on June 9, 2022 in Washington, D.C. For more information or to view a complete list of previous recipients of the Collier Trophy, please see the NAA website.

posted 04-27-2022 03:22 PM               

We spy with our little eyes... rover landing gear! During the Mars Helicopter's 26th flight, it took photos of the entry, descent, and landing gear Perseverance needed to safely land on Mars. You can see the protective backshell and massive dusty parachute.

posted 05-28-2022 05:59 PM               

NASA's Ingenuity Mars Helicopter Captures Video of Record Flight

Imagery has come down from Mars capturing a recent flight in which the rotorcraft flew farther and faster than ever before.

The Ingenuity Mars Helicopter's black-and-white navigation camera has provided dramatic video of its record-breaking 25th flight, which took place on April 8. Covering a distance of 2,310 feet (704 meters) at a speed of 12 mph (5.5 meters per second), it was the Red Planet rotorcraft's longest and fastest flight to date. (Ingenuity is currently preparing for its 29th flight.)

"For our record-breaking flight, Ingenuity's downward-looking navigation camera provided us with a breathtaking sense of what it would feel like gliding 33 feet above the surface of Mars at 12 miles per hour," said Ingenuity team lead Teddy Tzanetos of NASA's Jet Propulsion Laboratory in Southern California.

The first frame of the video clip begins about one second into the flight. After reaching an altitude of 33 feet (10 meters), the helicopter heads southwest, accelerating to its maximum speed in less than three seconds. The rotorcraft first flies over a group of sand ripples then, about halfway through the video, several rock fields. Finally, relatively flat and featureless terrain appears below, providing a good landing spot. The video of the 161.3-second flight was speeded up approximately five times, reducing it to less than 35 seconds.

The navigation camera has been programmed to deactivate whenever the rotorcraft is within 3 feet (1 meter) of the surface. This helps ensure any dust kicked up during takeoff and landing won't interfere with the navigation system as it tracks features on the ground.

Ingenuity's flights are autonomous. "Pilots" at JPL plan them and send commands to the Perseverance Mars rover, which then relays those commands to the helicopter. During a flight, onboard sensors – the navigation camera, an inertial measurement unit, and a laser range finder – provide real-time data to Ingenuity's navigation processor and main flight computer, which guide the helicopter in flight. This enables Ingenuity to react to the landscape while carrying out its commands.

Mission controllers recently lost communication with Ingenuity after the helicopter entered a low-power state. Now that the rotorcraft is back in contact and getting adequate energy from its solar array to charge its six lithium-ion batteries, the team is looking forward to its next flight on Mars.

posted 04-19-2023 04:52 PM               

Well, we don't see this every day!

For the first time in nearly two years, Perseverance is close enough to see the dust on the Mars Helicopter's rotors. From about 75 ft/23 m away, Ingenuity looks to be holding up well in the harsh Martian environment.

posted 01-25-2024 01:47 PM               

NASA's history-making Ingenuity Mars Helicopter has ended its mission at the Red Planet after surpassing expectations and making dozens more flights than planned. While the helicopter remains upright and in communication with ground controllers, imagery of its Jan. 18 flight sent to Earth this week indicates one or more of its rotor blades sustained damage during landing, and it is no longer capable of flight.

posted 01-31-2024 01:38 PM               

Join Tiffany Morgan, NASA's Mars Exploration Program Deputy Director, and Teddy Tzanetos, Ingenuity Project Manager, as they discuss the historic flights of the Mars Helicopter and what they could mean for future extraterrestrial aerial exploration.

posted 02-09-2024 06:25 PM               

The Ingenuity team has nicknamed the spot where the helicopter completed its final flight "Valinor Hills" after the fictional location in J.R.R. Tolkien's fantasy novels, which include "The Lord of the Rings" trilogy.

posted 02-26-2024 06:16 PM               

One rotor blade is broken off completely, the others have damaged tips.

posted 03-25-2024 09:22 PM               

SuperCam's RMI Spots Ingenuity's Broken Rotor

The Remote Microscopic Imager (RMI) camera aboard NASA's Perseverance Mars rover took these zoomed-in images of the Ingenuity Mars Helicopter and one of its rotor blades on Feb. 24, 2024, the 1,072nd Martian day, or sol, of the mission.

The mosaic shows the helicopter at right, standing at an angle near the apex of a sand ripple. About 49 feet (15 meters) to the west of the helicopter's location (just left of center in the image), a large portion of one of the helicopter's rotor blades lies on the surface. The Ingenuity team is considering a theory that the blade detached after the rotorcraft impacted the Martian surface at the conclusion of the helicopter's 72nd and final flight on Jan. 18, 2024.

This mosaic is made up of seven images taken by the RMI, which is part of the rover's SuperCam instrument. At the time these images were taken, the distance between the rover and helicopter was about 1,365 feet (415 meters). Each circular image has a field of view of 26 feet (7.8 meters) at this distance.

Able to spot a softball from nearly a mile away, the RMI allows scientists to take images of details from a long distance. It also provides fine details of nearby targets zapped by SuperCam's laser.

SuperCam is led by Los Alamos National Laboratory in New Mexico, where the instrument's body unit was developed. The mast unit, including the RMI used for these images, was developed and built by several laboratories of the CNRS (the French research center) and French universities under the contracting authority of Centre National d'Études Spatiales (CNES), the French space agency.

posted 12-12-2024 09:57 AM               

NASA Performs First Aircraft Accident Investigation on Another World

The review takes a close look the final flight of the agency's Ingenuity Mars Helicopter, which was the first aircraft to fly on another world.

Engineers from NASA's Jet Propulsion Laboratory in Southern California and AeroVironment are completing a detailed assessment of the Ingenuity Mars Helicopter's final flight on Jan. 18, 2024, which will be published in the next few weeks as a NASA technical report. Designed as a technology demonstration to perform up to five experimental test flights over 30 days, Ingenuity was the first aircraft on another world. It operated for almost three years, performed 72 flights, and flew more than 30 times farther than planned while accumulating over two hours of flight time.

Above: NASA's Ingenuity Mars Helicopter, right, stands near the apex of a sand ripple in an image taken by Perseverance on Feb. 24, 2024, about five weeks after the rotorcraft's final flight. Part of one of Ingenuity's rotor blades lies on the surface about 49 feet (15 meters) west of helicopter (at left in image). (NASA/JPL-Caltech)

The investigation concludes that the inability of Ingenuity's navigation system to provide accurate data during the flight likely caused a chain of events that ended the mission. The report's findings are expected to benefit future Mars helicopters, as well as other aircraft destined to operate on other worlds.

Final Ascent

Flight 72 was planned as a brief vertical hop to assess Ingenuity's flight systems and photograph the area. Data from the flight shows Ingenuity climbing to 40 feet (12 meters), hovering, and capturing images. It initiated its descent at 19 seconds, and by 32 seconds the helicopter was back on the surface and had halted communications. The following day, the mission reestablished communications, and images that came down six days after the flight revealed Ingenuity had sustained severe damage to its rotor blades.

What Happened

"When running an accident investigation from 100 million miles away, you don't have any black boxes or eyewitnesses," said Ingenuity's first pilot, Håvard Grip of JPL. "While multiple scenarios are viable with the available data, we have one we believe is most likely: Lack of surface texture gave the navigation system too little information to work with."

The helicopter's vision navigation system was designed to track visual features on the surface using a downward-looking camera over well-textured (pebbly) but flat terrain. This limited tracking capability was more than sufficient for carrying out Ingenuity's first five flights, but by Flight 72 the helicopter was in a region of Jezero Crater filled with steep, relatively featureless sand ripples.

One of the navigation system's main requirements was to provide velocity estimates that would enable the helicopter to land within a small envelope of vertical and horizontal velocities. Data sent down during Flight 72 shows that, around 20 seconds after takeoff, the navigation system couldn't find enough surface features to track.

Photographs taken after the flight indicate the navigation errors created high horizontal velocities at touchdown. In the most likely scenario, the hard impact on the sand ripple's slope caused Ingenuity to pitch and roll. The rapid attitude change resulted in loads on the fast-rotating rotor blades beyond their design limits, snapping all four of them off at their weakest point — about a third of the way from the tip. The damaged blades caused excessive vibration in the rotor system, ripping the remainder of one blade from its root and generating an excessive power demand that resulted in loss of communications.

Down but Not Out

Above: This graphic depicts the most likely scenario for the hard landing of NASAs Ingenuity Mars Helicopter during its 72nd and final flight on Jan. 18, 2024. (NASA/JPL-Caltech)

Although Flight 72 permanently grounded Ingenuity, the helicopter still beams weather and avionics test data to the Perseverance rover about once a week. The weather information could benefit future explorers of the Red Planet. The avionics data is already proving useful to engineers working on future designs of aircraft and other vehicles for the Red Planet.

"Because Ingenuity was designed to be affordable while demanding huge amounts of computer power, we became the first mission to fly commercial off-the-shelf cellphone processors in deep space," said Teddy Tzanetos, Ingenuity's project manager. "We're now approaching four years of continuous operations, suggesting that not everything needs to be bigger, heavier, and radiation-hardened to work in the harsh Martian environment."

Inspired by Ingenuity's longevity, NASA engineers have been testing smaller, lighter avionics that could be used in vehicle designs for the Mars Sample Return campaign. The data is also helping engineers as they research what a future Mars helicopter could look like — and do.

During a Wednesday, Dec. 11, briefing at the American Geophysical Union's annual meeting in Washington, Tzanetos shared details on the Mars Chopper rotorcraft, a concept that he and other Ingenuity alumni are researching. As designed, Chopper is approximately 20 times heavier than Ingenuity, could fly several pounds of science equipment, and autonomously explore remote Martian locations while traveling up to 2 miles (3 kilometers) in a day. (Ingenuity's longest flight was 2,310 feet, or 704 meters.)

"Ingenuity has given us the confidence and data to envision the future of flight at Mars," said Tzanetos.