NASA’s Ingenuity helicopter is the first spacecraft to successfully achieve controlled flight on another planet.Credit: NASA/JPL-Caltech/ASU/MSSS

ngenuity, NASA’s pint-sized Mars helicopter, has kicked up some surprising science on its flights over the red planet. When whizzing through the Martian air, its blades sometimes stir up a dust cloud that envelops and travels along with the tiny chopper.

In several videos of Ingenuity’s flights, planetary scientists have seen dust whirling beneath the helicopter’s rotors — even when Ingenuity is flying as high as 5 metres above the Martian surface. That suggests that dust can get lifted and transported in the thin Martian air more easily than researchers had suspected.

“It’s really cool,” says Mark Lemmon, a planetary scientist at the Space Science Institute in Boulder, Colorado.

Mars is a dusty planet, so it’s not surprising that the helicopter kicks up dust during takeoff and landing, much as helicopters on Earth do when operating in the desert. Engineers designed Ingenuity to operate with a lot of dust blowing around as it takes off and lands. But scientists are surprised by how the dust interacts with the drone during flight. By watching how Ingenuity entrains dust as it flies, researchers can better understand the dynamics of Mars’s thin atmosphere, where tornado-like ‘dust devils’ often form when the Sun heats the air and afternoon winds begin to blow.

“There’s an unanticipated atmospheric science experiment coming out of this,” says Jim Bell, a planetary scientist at Arizona State University in Tempe.

Ingenuity is what NASA calls a technology demonstration, whose only goal is to show that flight on Mars is possible. So "anything we can learn from it scientifically is icing on the cake", says Brian Jackson, a physicist at Boise State University in Idaho who studies Martian dust.

Bizarre dust clouds

Space scientists and amateur image processors have been analysing images and videos of the helicopter that NASA has posted online.

The agency's Perseverance rover carried Ingenuity to the surface of Mars in February. Its job is to roll around Jezero Crater and explore the rocks that were once part of an ancient lake, to look for signs of past life. In April, Ingenuity became the first machine to achieve powered flight on another planet. It has made seven flights so far.

On the first two flights, Ingenuity kicked up a fair amount of dust as it rose 3 to 5 metres above the surface, but it didn’t travel far from its takeoff point and the dust cloud phenomenon wasn’t pronounced. On its third flight, the helicopter rose 5 metres and then flew north from its takeoff point, kicking up a cloud from several light-coloured patches it flew over on the Martian surface. Those patches might be small hollows where dust has collected in the Martian landscape, says Lemmon. “A lot more dust comes up at that moment” when the helicopter flies over them, he says.

Ingenuity’s blades spin at more than 2,400 revolutions per minute — a dizzying rate necessary for the helicopter to achieve lift in the Martian atmosphere, which is just 1% the density of Earth's.

It was Ingenuity’s fourth flight, on 30 April, that really intrigued scientists. A video, recorded by Perseverance from a vantage point nearby, shows the helicopter rise, disappear from view, and then re-appear while enveloped in an enormous cloud of dust following a 133-metre flight.

The video confirms that Ingenuity was flying along with the 3.5-metre-per-second wind, says Håvard Grip, the helicopter's chief pilot at the Jet Propulsion Laboratory in Pasadena, California. "The dust was getting carried beneath us," he says.

Lemmon plans to compare tracks on the Martian surface left behind by natural dust devils with those where the helicopter kicked up the most dust. That will help researchers to better understand how winds blowing across Mars can lift dust and spin it into dust devils. The Martian atmosphere is so thin that scientists have had a hard time explaining how so much dust gets aloft, says Jackson. "We have to know how that first step in the process works," he says.

Quelle: nature 

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Update: 6.07.2021

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Mars Helicopter To Scout Rover Science Target

NASA’s Mars Ingenuity helicopter captured this image with its ground-facing navigation camera during its eighth flight on June 22.

The agency’s newest rover is trekking across the Martian landscape using a newly enhanced auto-navigation system.

NASA’s newest six-wheeled robot on Mars, the Perseverance rover, is beginning an epic journey across a crater floor seeking signs of ancient life. That means the rover team is deeply engaged with planning navigation routes, drafting instructions to be beamed up, even donning special 3D glasses to help map their course.

But increasingly, the rover will take charge of the drive by itself, using a powerful auto-navigation system. Called AutoNav, this enhanced system makes 3D maps of the terrain ahead, identifies hazards, and plans a route around any obstacles without additional direction from controllers back on Earth.

“We have a capability called ‘thinking while driving,’” said Vandi Verma, a senior engineer, rover planner, and driver at NASA’s Jet Propulsion Laboratory in Southern California. “The rover is thinking about the autonomous drive while its wheels are turning.”

That capability, combined with other improvements, might enable Perseverance to hit a top speed of 393 feet (120 meters) per hour; its predecessor, Curiosity, equipped with an earlier version of AutoNav, covers about 66 feet (20 meters) per hour as it climbs Mount Sharp to the southeast.

Vandi Verma, an engineer who now works with NASA’s Perseverance Mars rover, is seen here working as a driver for the Curiosity rover. The special 3D glasses she’s wearing are still used by rover drivers to easily detect changes in terrain that the rover may need to avoid.

Credits: NASA/JPL-Caltech

 

“We sped up AutoNav by four or five times,” said Michael McHenry, the mobility domain lead and part of JPL’s team of rover planners. “We’re driving a lot farther in a lot less time than Curiosity demonstrated.”

As Perseverance begins its first science campaign on the floor of Jezero Crater, AutoNav will be a key feature in helping get the job done.

This crater once was a lake, when, billions of years ago, Mars was wetter than today, and Perseverance’s destination is a dried-out river delta at the crater’s edge. If life ever took hold on early Mars, signs of it might be found there. The rover will gather samples over some 9 miles (15 kilometers), then prep the samples for collection by a future mission that would take them back to Earth for analysis.

“We’re going to be able to get to places the scientists want to go much more quickly,” said Jennifer Trosper, who has worked on every one of NASA’s Martian rovers and is the Mars 2020 Perseverance rover project manager. “Now we are able to drive through these more complex terrains instead of going around them: It’s not something we’ve been able to do before.”

The Human Element

Of course, Perseverance can’t get by on AutoNav alone. The involvement of the rover team remains critical in planning and driving Perseverance’s route. An entire team of specialists develops a navigation route along with planning the rover’s activity, whether it’s examining a geologically interesting feature on the way to its destination or, soon, taking samples.

Because of the radio signal delay between Earth and Mars, they can’t simply move the rover forward with a joystick. Instead, they scrutinize satellite images, sometimes donning those 3D glasses to view the Martian surface in the rover’s vicinity. Once the team signs off, they beam the instructions to Mars, and the rover executes those instructions the following day.

Perseverance’s wheels were modified as well to help with just how swiftly those plans are executed: Along with being slightly greater in diameter and narrower than Curiosity’s wheels, they each feature 48 treads that look like slightly wavy lines, as opposed to Curiosity’s 24 chevron-pattern treads. The goals were to help with traction as well as durability.

“Curiosity couldn’t AutoNav because of the wheel-wear issue,” Trosper said. “Early in the mission, we experienced small, sharp, pointy rocks starting to put holes in the wheels, and our AutoNav didn’t avoid those.”

Higher clearance for Perseverance’s belly also enables the rover to roll safely over rougher ground – including good-size rocks. And Perseverance’s beefed-up auto-navigation capabilities include ENav, or enhanced navigation, an algorithm-and-software combination that allows more precise hazard detection.

Unlike its predecessors, Perseverance can employ one of its computers just for navigation on the surface; its main computer can devote itself to the many other tasks that keep the rover healthy and active.

This Vision Compute Element, or VCE, guided Perseverance to the Martian surface during its entry, descent, and landing in February. Now it’s being used full-time to map out the rover’s journey while helping it avoid trouble along the way.

The rover also keeps track of how far it’s moved from one spot to another using a system called “visual odometry.” Perseverance periodically captures images as it moves, comparing one position to the next to see if it moved the expected distance.

Team members say they look forward to letting AutoNav “take the wheel.” But they’ll also be ready to intervene when needed.

And just what is it like to drive on Mars? The planners and drivers say it never gets old.

“Jezero is incredible,” Verma said. “It’s a rover driver’s paradise. When you put on the 3D glasses, you see so much more undulation in the terrain. Some days I just stare at the images.”

Flight 9 Was a Nail-Biter, but Ingenuity Came Through With Flying Colors
Written by Håvard F. Grip, Ingenuity Chief Pilot, and Ken Williford, Perseverance Deputy Project Scientist

NASA’s Perseverance Mars rover took this image overlooking the “Séítah” region using its navigation camera. The agency’s Ingenuity helicopter flew over this region during its ninth flight, on July 5. Credit: NASA/JPL-Caltech. Download image ›

It has been a week of heightened apprehension on the Mars Helicopter team as we prepared a major flight challenge for Ingenuity. We uplinked instructions for the flight, which occurred Monday, July 5 at 2:03 am PT, and waited nervously for results to arrive from Mars later that morning. The mood in the ground control room was jubilant when we learned that Ingenuity was alive and well after completing a journey spanning 2,051 feet (625 meters) of challenging terrain.

Flight 9 was not like the flights that came before it. It broke our records for flight duration and cruise speed, and it nearly quadrupled the distance flown between two airfields. But what really set the flight apart was the terrain that Ingenuity had to negotiate during its 2 minutes and 46 seconds in the air – an area called “Séítah” that would be difficult to traverse with a ground vehicle like the Perseverance rover. This flight was also explicitly designed to have science value by providing the first close view of major science targets that the rover will not reach for quite some time. 

Flying with our eyes open

 

 

In each of its previous flights, Ingenuity hopped from one airfield to another over largely flat terrain. In planning the flights, we even took care to avoid overflying a crater. We began by dipping into what looks like a heavily eroded crater, then continued to descend over sloped and undulating terrain before climbing again to emerge on a flat plain to the southwest.

It may seem strange that the details of the terrain would matter as much as they do for a vehicle that travels through the air. The reason has to do with Ingenuity’s navigation system and what it was originally designed for: a brief technology demonstration at a carefully chosen experimental test site.

When we as human beings look at moving images of the ground, such as those taken by Ingenuity’s navigation camera, we instantly have a pretty good understanding of what we’re looking at. We see rocks and ripples, shadows and texture, and the ups and downs of the terrain are relatively obvious. Ingenuity, however, doesn’t have human perception and understanding of what it’s looking at. It sees the world in terms of individual, anonymous features – essentially dots that move around with time – and it tries to interpret the movement of those dots.

To make that job easier, we gave Ingenuity’s navigation algorithm some help: We told it that those features are all located on flat ground. That freed the algorithm from trying to work out variations in terrain height, and enabled it to concentrate on interpreting the movement of the features by the helicopter’s movements alone. But complications arise if we then try to fly over terrain that isn’t really flat. 

Differences in terrain height will cause features to move across the field of view at different rates, and Ingenuity’s navigation algorithm still “assumes” the ground below is flat. It does its best to explain the movement of the features by changes in the helicopter’s movements, which can lead to errors. Most significantly, it can result in errors in the estimated heading, which will cause the helicopter to fly in a different direction than intended.

NASA's Ingenuity Mars Helicopter captured this image, which features tracks made by the Perseverance rover, using its high-resolution color camera during its ninth Red Planet flight, on July 5, 2021. (Image credit: NASA/JPL-Caltech)

Getting ready for a bumpy flight

The assumption about the ground being flat is baked into the design of the algorithm, and there is nothing we can do about that when planning the flights. What we can do is to anticipate the issues that will arise due to this assumption and to mitigate them to the greatest possible extent in terms of how we plan the flights and the parameters we give the software.

We use simulation tools that allow us to study the likely outcome of the flight in detail prior to carrying it out. For Flight 9, a key adaptation of the flight plan was to reduce our speed at the crucial point when we dipped into the crater. Although it came at the cost of extending the flight time, it helped mitigate early heading errors that could grow into a large cross-track position error. We also adjusted some of the detailed parameters of the navigation algorithm that we have not had to touch so far in prior flights. And we carved out a much larger airfield than in prior flights, with a radius of 164 feet (50 meters). We ended up landing approximately 154 feet (47 meters) away from the center of that airfield.

In the week ahead, Ingenuity will send back color images that Perseverance’s scientists are looking forward to studying. Captured in those images are rock outcrops that show contacts between the major geologic units on Jezero Crater’s floor. They also include a system of fractures the Perseverance team calls “Raised Ridges,” which the rover’s scientists hope to visit in part to investigate whether an ancient subsurface habitat might be preserved there.

Finally, we’re hoping the color images will provide the closest look yet at “Pilot Pinnacle,” a location featuring outcrops that some team members think may record some of the deepest water environments in old Lake Jezero. Given the tight mission schedule, it’s possible that they will not be able to visit these rocks with the rover, so Ingenuity may offer the only opportunity to study these deposits in any detail.

Where is the Mars Helicopter?

Quelle: NASA

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Update: 12.07.2021

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Open-source flight software called F Prime used on NASA’s Ingenuity Mars Helicopter

What do small satellites called CubeSats and the NASA Ingenuity Mars Helicopter have in common? It turns out that open-source software developed for CubeSats, small spacecraft, and instruments is being used by the Ingenuity Mars Helicopter.

NASA recently provided some insight into F Prime, it’s history and uses.

When NASA’s Ingenuity Mars Helicopter hovered above the Red Planet April 19 on its maiden voyage, the moment was hailed as the first instance of powered, controlled flight on another planet. Figuring out how to fly on Mars, where the air is thin but gravity is about a third of that on Earth, took years of work. Along with the challenge of developing a craft that was up to the task, the mission needed software to make the unprecedented flights possible.

So they turned to F Prime, a reusable, multi-mission flight software framework designed for CubeSats, small spacecraft, and instruments. The program was initially developed in 2013 by a team led by Tim Canham at NASA’s Jet Propulsion Laboratory in Southern California with the aim of creating a low-cost, portable, pliable software architecture option that would allow components written for one application to be reused easily in other applications and run on a range of processors.

In 2017, the team pushed for F Prime to be released as open-source, meaning anyone could freely access the software’s source code, allowing external collaborators, universities, and the general public to use the framework on their own projects. It is one of hundreds of codes NASA makes available to the public for free, both as open-source or through its software catalog.

“F Prime has enabled a lot of goals we’ve had at JPL to design a truly reusable multi-mission flight architecture with the added bonus of the open-source collaboration and visibility afforded by the Mars Helicopter project,” Canham said. “It’s kind of an open-source victory, because we’re flying an open-source operating system and an open-source flight software framework, and flying commercial parts that you can buy off the shelf, if you wanted to do this yourself someday.”

Before Ingenuity, F Prime (also written as F’) had already been put through its spacecraft paces, operating successfully aboard the ISS RapidScat scatterometer instrument on the International Space Station since 2014 and JPL’s ASTERIA CubeSat in 2017. Looking forward, F Prime is scheduled to run on projects including NASA’s Lunar Flashlight CubeSat, which will look for surface ice in the Moon’s craters; the agency’s Near-Earth Asteroid Scout CubeSat, which will map an asteroid; and potentially JPL’s Ocean Worlds Life Surveyor instrument, which would help search for water-based life in our solar system.

Aadil Rizvi, flight software lead for Lunar Flashlight and NEA Scout at JPL, says F Prime provides an out-of-the-box solution for several flight software services, such as commanding, telemetry, parameters, and sequencing for the spacecraft. There’s also a sort of “auto-coding” tool that makes F Prime highly portable for use across missions.

“This makes it quite easy to drop in a software component from something like Mars Helicopter into another mission’s flight software such as Lunar Flashlight or make the component available for open-source use by anyone else using F Prime,” Rizvi said. “And it’s pretty cool that a significant portion of software used on the Mars Helicopter is identical to software on another spacecraft going to the Moon, or an asteroid, or sitting on a student’s desk.”

Quelle: spaceQ

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Update: 16.07.2021

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MARS HELICOPTER SCOUTS RISKY TERRAIN FOR PERSEVERANCE ROVER

The Ingenuity Mars helicopter has proven itself a valuable asset to Perseverance, scouting out terrain that the rover can’t cross.

NASA’s Ingenuity Mars helicopter is proving its worth on the Red Planet, acting as an advance sentinel over dune-covered terrain that the rover Perseverance is avoiding.

 

Ingenuity's ninth flight over the Séítah dune field was a risky one. Perseverance is driving around this region because “sand is a big concern,” says Olivier Toupet (NASA-JPL), who leads the team that plans Perseverance's drives. “If we drive downhill into a dune, we could embed ourselves into it and not be able to get back out.”

But the flight over uneven terrain was risky for Ingenuity as well, because the helicopter has to find its own way as it flies using autonomous navigation. The varying heights of the terrain can confuse the nav system. Håvard F. Grip and Ken Williford (on the Ingenuity and Perseverance teams, respectively) outline the procedure they had to take in their latest blog.

Ultimately, the flight was a success, again breaking records both in flight duration (2 minutes and 46 seconds) and cruise speed as it crossed over 625 meters of land. Ingenuity snapped some amazing color images of the dunes from its vantage point 10 meters overhead — views we would not have seen otherwise.

Generally, rovers rely on NASA’s HiRISE (the High Resolution Image Science Experiment) on the Mars Reconnaissance Orbiter for overhead views. Those images have a resolution down to about 3 feet (1 meter). Ingenuity complements that data with a much higher-resolution view of the terrain.

Particularly intriguing are bedrock and raised-ridge features beyond the dune field that Ingenuity spied during its July 5th flight. Planners hope to have Perseverance drive over to these ridges for a closer look. These sorts of features hint at a fracture system, which may have channeled flowing water in the past.

Early on in the history of Mars, Jezero Crater hosted a lake, and regions of associated ancient water flows are prime sites to look for possible signs of past life. A principal objective for Perseverance is to collect and cache regolith samples from regions such as these for eventual return to Earth. In the coming years, a second mission combining a sample return platform and ascent rocket will touch down nearby to take these samples home.

“Once a rover gets close enough to a location, we get ground-scale images that we can compare to orbital images,” says Ken Williford (NASA's Jet Propulsion Laboratory). “With Ingenuity, we now have this intermediate-scale imagery that nicely fills the gap in resolution.”

BREAKING RECORDS, TAKING NAMES

After the helicopter’s first historic flight on April 19th, it has flown nine times total so far, breaking records nearly every time it takes to the skies. The fifth flight saw Ingenuity’s first landing at a new location, as it flew 129 meters (423 feet) to the south of Wright Brothers Field to a new airfield. This marked the formal end of the technology demonstration, but the solar-powered helicopter was in good health, and NASA extended its operations into a new phase.

Since then, the helicopter has kept pace with Perseverance, landing at several new airfields. The team plans to continue to fly Ingenuity every few weeks at least until the end of August, when Mars will recede behind the Sun from Earth’s point of view. (Mars reaches solar conjunction on October 8th.)

The helicopter's operations phase helps pave the way for missions such as Dragonfly, a full scale nuclear-powered helicopter that may begin flying the skies of Saturn’s large moon Titan as soon as 2036.

It will be fascinating to follow Ingenuity as the helicopter completes its final flights on Mars in the coming weeks.

Quelle: Sky&Telescope