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Tricky Terrain: Helping to Assure a Safe Rover Landing – NASA's Mars Exploration Program – NASA Mars Exploration

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How two new technologies will help Perseverance, NASA’s most sophisticated rover yet, touch down onto the surface of Mars this month.


After a nearly seven-month journey to Mars, NASA’s Perseverance rover is slated to land at the Red Planet’s Jezero Crater Feb. 18, 2021, a rugged expanse chosen for its scientific research and sample collection possibilities.

But the very features that make the site fascinating to scientists also make it a relatively dangerous place to land – a challenge that has motivated rigorous testing here on Earth for the lander vision system (LVS) that the rover will count on to safely touch down.

“Jezero is 28 miles wide, but within that expanse there are a lot of potential hazards the rover could encounter: hills, rock fields, dunes, the walls of the crater itself, to name just a few,” said Andrew Johnson, principal robotics systems engineer at NASA’s Jet Propulsion Laboratory in Southern California. “So, if you land on one of those hazards, it could be catastrophic to the whole mission.”

Enter Terrain-Relative Navigation (TRN), the mission-critical technology at the heart of the LVS that captures photos of the Mars terrain in real time and compares them with onboard maps of the landing area, autonomously directing the rover to divert around known hazards and obstacles as needed.

Masten’s Xombie VTVL System: Masten’s Xombie VTVL system sits on a launchpad in Mojave, California in December 2014, prepared for a flight test that would help prove lander vision system capabilities for the Mars 2020 Perseverance rover mission. Credit: Masten Space Systems. Download image ›

“For Mars 2020, LVS will use the position information to figure out where the rover is relative to safe spots between those hazards. And in one of those safe spots is where the rover will touch down,” explained Johnson.

If Johnson sounds confident that LVS will work to land Perseverance safely, that’s because it allows the rover to determine its position relative to the ground with an accuracy of about 200 feet or less. That low margin of error and high degree of assurance are by design, and the result of extensive testing both in the lab and in the field.

“We have what we call the trifecta of testing,” explained JPL’s Swati Mohan, guidance, navigation, and control operations lead for Mars 2020.

Mohan said that the first two testing areas – hardware and simulation – were done in a lab.

“That’s where we test every condition and variable we can. Vacuum, vibration, temperature, electrical compatibility – we put the hardware through its paces,” said Mohan. “Then with simulation, we model various scenarios that the software algorithms may encounter on Mars – a too-sunny day, very dark day, windy day – and we make sure the system behaves as expected regardless of those conditions.”

But the third piece of the trifecta – the field tests – require actual flights to put the lab results through further rigor and provide a high level of technical readiness for NASA missions. For LVS’s early flight tests, Johnson and team mounted the LVS to a helicopter and used it to estimate the vehicle’s position automatically as it was flying.

“That got us to a certain level of technical readiness because the system could monitor a wide range of terrain, but it didn’t have the same kind of descent that Perseverance will have,” said Johnson. “There was also a need to demonstrate LVS on a rocket.”

That need was met by NASA’s Flight Opportunities program, which facilitated two 2014 flights in the Mojave Desert on Masten Space Systems’ Xombie – a vertical takeoff and vertical landing (VTVL) system that functions similarly to a lander. The flight tests demonstrated LVS’s ability to direct Xombie to autonomously change course and avoid hazards on descent by adopting a newly calculated path to a safe landing site. Earlier flights on Masten’s VTVL system also helped validate algorithms and software used to calculate fuel-optimal trajectories for planetary landings.

“Testing on the rocket laid pretty much all remaining doubts to rest and answered a critical question for the LVS operation affirmatively,” said JPL’s Nikolas Trawny, a payload and pointing control systems engineer who worked closely with Masten on the 2014 field tests. “It was then that we knew LVS would work during the high-speed vertical descent typical of Mars landings.”

Johnson added that the suborbital testing in fact increased the technology readiness level to get the final green light of acceptance into the Mars 2020 mission.

“The testing that Flight Opportunities is set up to provide was really unprecedented within NASA at the time,” said Johnson. “But it’s proven so valuable that it’s now becoming expected to do these types of flight tests. For LVS, those rocket flights were the capstone of our technology development effort.”

With the technology accepted for Mars 2020, the mission team began to build the final version of LVS that would fly on Perseverance. In 2019, a copy of that system flew on one more helicopter demonstration in Death Valley, California, facilitated by NASA’s Technology Demonstration Missions program. The helicopter flight provided a final check on over six-years of multiple field tests.

But Mohan pointed out that even with these successful demonstrations, there will be more work to do to ensure a safe landing. She’ll be at Mission Control for the landing, monitoring the health of the system every step of the way.

“Real life can always throw you curve balls. So, we’ll be monitoring everything during the cruise phase, checking power to the camera, making sure the data is flowing as expected,” Mohan said. “And once we get that signal from the rover that says, ‘I’ve landed and I’m on stable ground,’ then we can celebrate.”

About Flight Opportunities

The Flight Opportunities program is funded by NASA’s Space Technology Mission Directorate (STMD) and managed at NASA’s Armstrong Flight Research Center in Edwards, California. NASA’s Ames Research Center in California’s Silicon Valley manages the solicitation and evaluation of technologies to be tested and demonstrated on commercial flight vehicles.

About Technology Demonstration Missions

Also under the umbrella of STMD, the program is based at NASA’s Marshall Space Flight Center in Huntsville, Alabama. The program bridges the gap between scientific and engineering challenges and the technological innovations needed to overcome them, enabling robust new space missions.

More About the Mission

A key objective for Perseverance’s mission on Mars is astrobiology, including the search for signs of ancient microbial life. The rover will characterize the planet’s geology and past climate, pave the way for human exploration of the Red Planet, and be the first mission to collect and cache Martian rock and regolith (broken rock and dust).

Subsequent missions, currently under consideration by NASA in cooperation with the European Space Agency, would send spacecraft to Mars to collect these cached samples from the surface and return them to Earth for in-depth analysis.

The Mars 2020 mission is part of a larger program that includes missions to the Moon as a way to prepare for human exploration of the Red Planet. Charged with returning astronauts to the Moon by 2024, NASA will establish a sustained human presence on and around the Moon by 2028 through NASA’s Artemis lunar exploration plans.

JPL, which is managed for NASA by Caltech in Pasadena, California, built and manages operations of the Perseverance rover.

For more about Perseverance:

mars.nasa.gov/mars2020/

nasa.gov/perseverance

News Media Contact
DC Agle
Jet Propulsion Laboratory, Pasadena, Calif.
818-393-9011
agle@jpl.nasa.gov

Written By Nicole Quenelle
NASA’s Flight Opportunities Program

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Monday fireball a small comet fragment say U of A scientists – EverythingGP

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The glowing fireball lit up the sky early Monday morning (photo courtesy of Graham Knutson)

By Canadian Press

Comet Fragment

Feb 25, 2021 4:02 PM

The mystery of what caused a giant fireball that lit up the sky over much of Alberta earlier this week has been solved.

Scientists at the University of Alberta say calculations using two observation sites show it was a small piece of a comet that burned up in the atmosphere.

Hundreds of people from Calgary to Fort McMurray and Medicine Hat to Grande Prairie reported seeing the bright flash in the sky at about 6:30 a.m on Monday.

Patrick Hill of the Department of Earth and Atmospheric Sciences says the chunk burned up immediately after giving what he describes as a “spectacular flash.”

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Sudbury native aiding NASA rover's hunt for life on Mars – The Sudbury Star

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Raymond Francis hopes to become a Canadian Space Agency astronaut

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The NASA rover mission scouring Mars for ancient life has a connection to Sudbury.

Raymond Francis, who graduated from Western University in 2014 with a PhD in computer engineering and planetary science, is an engineer at NASA’s Jet Propulsion Laboratory in Pasadena, Calif.

Francis, whose aspirations include becoming a Canadian Space Agency astronaut — maybe even one of the first on the red planet — is part of the team helping guide the rover Perseverance through Mars’s Jezero crater, which scientists say was a lake 3.5 billion years ago.

It is the first time a Mars rover will be collecting rock and soil, which will be stored until they can be returned to Earth.

“If ever there was life on Mars, this is the time it may well have arisen,” Francis said. “We would be elated if we found signs of ancient life on Mars. No one is expecting current life, but we explicitly have a goal of finding signs of life.”

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Jezero, which means lake in Slavic languages, is named after a settlement.

“The lake was there for a long time, because the river flowing into had enough time to build up a delta, the kind you find at the mouth of the Mississippi or the Nile,” Francis said.

Sudbury native Raymond Francis, who graduated from Western in 2014 with a PhD in computer engineering and planetary science, and will be helping guide the rover Perseverance during its time on Mars.
Sudbury native Raymond Francis, who graduated from Western in 2014 with a PhD in computer engineering and planetary science, and will be helping guide the rover Perseverance during its time on Mars. SunMedia

“Deltas are also a good place to preserve signs of life, because they are constantly setting down new sediment. If there are living things in that lake, they can get buried in the sediment and preserved.”

But even if they don’t find life, the research into Mars’s environment, history and evolution would be incredibly valuable, he said.

“Any lake like this on Earth 3.5 billion years ago was probably full of microbes,” Francis said. “If this one on Mars was not, it tells us something about the difference between these two planets, regardless of life.”

While noisy and chaotic, Perseverance’s landing last Thursday — NASA shared video online — “worked out almost perfectly,” he said.

“People have put a lot of their life into this for the last decade and a lot of things had to go right for that landing to succeed …,” Francis said. “(At) each critical juncture, you could see people getting more hopeful.”

Now that Perseverance has landed, Francis’s work begins.

As science engineering liaison, he helps co-ordinate discussions of what the science team wants to do.

“They might be what observations to make, which experiments to run, where to drive the rover to make our next studies,” he said.

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The rover is “greatly improved” from its predecessor, Curiosity.

“It looks a lot like Curiosity rover, but it is not,” Francis said. “We have greatly improved capabilities and our autonomous driving system is much improved. We’ll be able to drive farther and faster.”

Francis also be part of operating its artificial intelligence system.

“I’m am going to have a role in deploying that software and making sure it gives us good science data,” he said.

Francis also runs a “supercam,” or laser geochemical spectrometer, he said.

Their work is being done on “Mars time,” where a day last 24 hours and 38 minutes and scientists will give up regular sleep cycles to use every second.

“The rover works best during the day on Mars, so we can spend less energy on heating because the sun is up and we can easily take pictures,” he said.

Rock and other samples collected by the rover will be retrieved, he said, likely in two missions in the early 2030s: one to land, pick up samples and lift them into orbit; another to carry them from Mars to Earth.

In earlier interviews, Francis said Sudbury and Science North helped shape his interest in science and space.

Francis told Tilbury District High School students in southern Ontario a few years ago about an encounter that changed his life.

“Probably the first time that happened to me was when I was … [in] first grade,” Francis said. “I grew up in Sudbury and there was a place there called Science North, a public science centre. And they had Bob Thirsk – a Canadian astronaut … and he came by with an American astronaut who had already flown. And they gave this presentation about ‘look, this is what it’s like to operate a space shuttle.’”

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“I still have the little poster he signed,” Francis added.

Thirsk would later become the first Canadian to fly at length in the International Space Station, in 2009.

Earlier this year, he told Quirks & Quarks, a science show on CBC Radio, that living in Sudbury in some ways helped prepare him for this Mars mission.

“You’re from Sudbury, which is a big mining town,” Quirks & Quarks asked. “And after building a career in robotics and space science, you’ve been led back to rocks. They’re just rocks on another world.”

“That’s right,” Francis replied. “And honestly, during my PhD studies in how to teach computers to look at rocks, I spent some time up in Sudbury looking at those. The mines in Sudbury are the results of an ancient impact crater that’s not quite as old as Jezero, but the impact geology is a very good analogue for the types of large scale impact sites we find in craters on Mars.

“So going home to Sudbury was actually a very useful thing for getting prepared for these kinds of studies on Mars.

HRivers@postmedia.com

Twitter: @SudburyStar

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Prairie fireball was comet fragment burning up in Earth's atmosphere – CBC.ca

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The fireball that lit up the sky across the Prairies on Monday morning was a small piece of a comet that burned up in the atmosphere, researchers at the University of Alberta say.

“Using two observation sites, we were able to calculate both its trajectory and velocity, which tell us about the origin of the meteor and reveal that it was a piece of a comet,” Patrick Hill, post-doctoral fellow in the Department of Earth and Atmospheric Sciences, said in a news release Thursday.

“This chunk was largely made of dust and ice, burning up immediately without leaving anything to find on the ground — but instead giving us a spectacular flash.”

The flash, captured by dozens of doorbell cameras and dashcams, occurred at 6:23 a.m. local time as the debris streaked through the sky to a final point on its trajectory 120 kilometres north of Edmonton, the researchers said.

The flash was visible throughout Alberta and parts of Saskatchewan due to the unusually high altitude of the fireball, they said.

WATCH | Fireball flashes across the Prairie sky:

A fireball buzzed over the Prairies on Monday, temporarily piercing the dark of the early morning sky with a flash of blinding blue light. 0:48

The chunk, likely only tens of centimetres across in size, was travelling at more than 220,000 km/h when it entered the atmosphere, they said.

“This incredible speed and the orbit of the fireball tell us that the object came at us from way out at the edge of the solar system — telling us it was a comet, rather than a relatively slower rock coming from the asteroid belt,” Chris Herd, curator of the University of Alberta Meteorite Collection and science professor, said in the release.

“Comets are made up of dust and ice and are weaker than rocky objects, and hitting our atmosphere would have been like hitting a brick wall for something travelling at this speed,” Herd said.

‘This is an incredible mystery to have solved’

While rocky objects usually burn up between 15 to 20 kilometres above the ground, Monday’s fireball occurred at an altitude of 46 kilometres allowing the flash to be seen across a wide area.

“All meteoroids — objects that become meteors once they enter Earth’s atmosphere — enter at the same altitude and then start to burn up with friction,” Hill said.

“Sturdier, rocky meteoroids can sometimes survive to make it to the ground, but because this was going so fast and was made of weaker material, it flashed out much higher in the atmosphere and was visible from much farther away.”

The research team calculated the trajectory of the fireball by using dark-sky images captured at the Hesje Observatory at the Augustana Miquelon Lake Research Station and at Lakeland College’s observation station in Vermilion, Alta., the release said. 

“This is an incredible mystery to have solved,” Herd said. “We’re thrilled that we caught it on two of our cameras, which could give everyone who saw this amazing fireball a solution.”

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