Perseverance on Mars: February 18, 2021

(Mars 2020 getting ready for launch last year.)

I’ll be looking at NASA’s Mars 2020 Ingenuity helicopter, the spacecraft, and an experimental oxygen generator.

With a quick look at news of the mission’s landing this afternoon.

Outward Bound: July 30, 2020

Mars 2020 in flight. (July 30, 2020)

Mars 2020’s launch, last July, wasn’t perfect. Takeoff was a few milliseconds early.

Once in orbit, the spacecraft’s onboard computer noticed unexpected conditions, shut down all but vital systems, and radioed mission controllers that it was in safe mode.

The next day we learned that the spacecraft had cooled off more than expected while in Earth’s shadow. Non-vital systems were powered back up. And, as JPL deputy project manager Matt Wallace said, “Next stop, Jezero Crater.” (July 30-31, 2020)

Meanwhile, I’d been following NASA’s online coverage. And saving screenshots.

Mars 2020 Launch in Pictures and Video

3:09 after liftoff. (July 30, 2020)
(Three minutes and nine seconds after liftoff. Attitude control jet is firing. (July 30, 2020))

5:27 after liftoff. (July 30, 2020)
(Five minutes and 27 seconds after liftoff. (July 30, 2020))

Just shy of two and a half hours of NASA’s Mars 2020 launch coverage is still available on YouTube:

Experiments, Acronyms and a Helicopter

Jet Propulsion Laboratory in Pasadena, California.
(From Alan Mak, via Wikimedia Commons, used w/o permission.)
(Jet Propulsion Laboratory Control Room. (2005))

Let’s see. Last year I said I’d be talking about the first Martian helicopter, biosignatures and the MOXI experiment at some unspecified future date.

I got around to briefly discussing biosignatures last month. (January 16, 2021)

Recapping, biosignatures are something we can measure that indicates biological processes: life. Oxygen in Earth’s atmosphere, for example.

Today I’ll be talking about the MOXI experiment.

After taking a look at the Mars 2020 spacecraft.

New Spacecraft, Old(ish) Technology

(From JPL/NASA, used w/o permission.)
(Mars 2020 Flight System in Launch / Cruise Configuration.)

The Mars 2020 Flight System includes new technology. But this isn’t our first flight to Mars. Some of the tech was designed for the 2011 Mars Science Laboratory mission and Curiosity rover. Some of the MSL systems needed tweaking for Mars 2020.1

Acronyms (Mostly) Deciphered

JPL/NASA's Figure 6. Mars 2020 flight system in the Launch / Cruise Configuration. (2014-2017)
(From JPL/NASA, used w/o permission.)
(Mars 2020 flight system illustration.)

MSL is technospeak for Mars Science Laboratory, a mission launched in 2011. After a little digging, I learned what other acronyms in that illustration mean.

  • BTP: Build-to-Print
  • CEDL: Cruise, Entry, Descent and Landing
  • EDL Cameras: Entry, Descent and Landing Cameras
  • EECAMs: Enhanced Engineering Cameras
  • FSW: JPL Flight Software
  • gDRT: high pressure gas-driven dust removal tool
  • GN&C: Guidance, Navigation and Control
  • MEDLI2: Mars Entry, Descent, and Landing Instrumentation
  • MSL: Mars Science Laboratory
  • TDS: Terminal Descent Sensor
  • TRN: Terrain Relative Navigation (a technology for improving EDL capabilities)

T-0 Purge, though: that’s still a mystery.

My guess is that it’s a T-something gaseous purge system that’s designed to get toxic or damaging chemicals away from instruments and people. But that’s just a guess.

TRN, Terrain Relative Navigation, is something new. The Mars 2020 TRN system compares what it ‘sees’ during descent with images from orbital surveys. This lets the TRN system figure out where it is. And where it should go to land safely.2

Perseverance: a Rover With MOXIE

Mars Oxygen In-Situ Resource Utilization Experiment (MOXIE).
(From NASA/JPL-Caltech, used w/o permission.)
(Lowering MOXIE into the Perseverance rover. (March 21, 2019))

MOXIE is the Mars Oxygen In-Situ Resource Utilization Experiment.

It’s very roughly the size of a car battery, 9.4 by 9.4 by 12.2 inches, weighs around 33 pounds and should produce up to 10 grams of oxygen per hour.

That’s nowhere near enough for astronauts on Mars. But that’s not MOXIE’s mission. MOXIE, like the Mars 2020’s helicopter, is a technical demonstration. It’s there to see if what we figure should work, will work on Mars.

“…MOXIE makes oxygen like a tree does. It inhales carbon dioxide and exhales oxygen….”

That overview of MOXIE’s function isn’t wrong. MOXIE takes in Martian air, which isn’t quite pure carbon dioxide, and extracts the oxygen.

Photosynthetic organisms like trees do the same thing. Sort of. They take energy from sunlight, storing it in carbohydrates, with oxygen as a byproduct.

MOXIE works the same way. Except it uses electrical energy and a solid oxide electrolyzer cell (SOEC) to separate carbon dioxide into oxygen and carbon monoxide. Without, as far as I can tell, involving water.

MOXIE’s SOEC has a nonporous solid electrolyte between two porous electrodes.

Thermal dissociation and electrocatalysis liberates an oxygen atom from carbon dioxide. In other words, MOXIE’s SOEC heats Martian air and zaps it, breaking carbon dioxide into carbon and oxygen atoms.

Then oxygen ion valencies in the electrolyte’s crystal lattice transport oxygen ions to an electrolyte-anode interface. Uff da. more technojargon. I’ll say that electricity sorts what SOEC makes into oxygen and carbon atoms. And leave it at that.

So MOXIE works just like trees.

Except for how it doesn’t.3

Augustin Thompson’s “Moxie Nerve Food”

Moxie logo. (ca. 1922)Starting around 1876, an enterprising New Englander promoted “Moxie Nerve Food” as a cure for pretty much everything.

Moxie was purportedly particularly potent for those suffering nervousness, insomnia, paralysis, and softening of the brain.

All of which are real health issues.

Moxie Nerve Food’s active ingredient was gentian root.

Moxie is still sold in New England. Unlike Bailey Radium Laboratories’ “Perpetual Sunshine,” Radithor. That stuff’s no longer available. Partly because Eben Byers, an enthusiastic imbiber, was eventually buried in a lead-lined coffin. And that’s another topic.

Thompson may or may not have gotten the name for his Moxie Nerve Food from an Abenaki word meaning “dark water.” Abenaki is an Algonquian language, spoken by folks not all that far from New England.4 so that’s possible.

Maybe an MIT scientist associated with the MOXIE experiment thought having oxygen generator named after a regional beverage was funny. Or maybe not. Either way:

The Story Behind the Name
“MOXIE is a short, snappy name for a tool that helps lead to human footprints on Mars. It helps humans explore Mars by making OXygen. It works “In situ” (in place) on the Red Planet, and is an Experiment
“‘Moxie’ can also be a personality trait. Someone with moxie is considered bold and adventurous, hardy and spirited! No one is sure, but the word may trace back to Native American place names for ‘dark water.’ In the late 1800s, people drank ‘Moxie,’ a tonic and later a soft drink. Because the drink claimed health benefits, people began using moxie to mean vitality and endurance. It surely endures in American vocabulary today! You can still drink Moxie in some old-time, nostalgic soda-pop shops today”

Ingenuity: “… Just to Show That You Can Do It”

NASA's Mars helicopter Ingenuity.
(From NASA, used w/o permission.)
(If successful, Ingenuity will make the first powered flight on Mars.)

Ingenuity’s mission is simple: fly at least once, within 30 days of Mars 2020’s landing in Jezero Crater. It’s a test flight.

Folks at Caltech’s JPL, Jet Propulsion Laboratory, have a short list of goals for Ingenuity:

  • Achieve powered flight
  • Show that its miniaturized avionics and motors work
  • Fly autonomously

We’ve got aircraft that do all of the above. On Earth.

Mars is another matter.

Its surface gravity is only a third of Earth’s. But its atmosphere is maybe 1% as thick as ours. That’s why Ingenuity’s rotors are about four feet across: 1.2 meters.

“Fly autonomously” is a fancy way of saying that Ingenuity pilots itself. Mission controllers tell it where to go, but Ingenuity works out how to get there. I’m oversimplifying the situation enormously. But that’s the gist.

We’ve got autonomous aircraft and miniaturized avionics, and powered flight stopped being a novelty a century back now.

But a self-piloting helicopter on Mars? That recharges itself with a solar array? That’s new.

Flying robots equipped for science missions on Mars will come later.

As a narrator said in this JPL video, “sometimes you have to do something just to show that you can do it.”

Ingenuity carries two cameras: one black and white, one color. Again, it’s mission is testing technology, not doing science.5

But as as Bob Balaram, JPL’s Mars Helicopter Chief Engineer said — “I’m sure we’ll return a few … because they … look cool.”

After Landing: Analysis, Collecting and Caching

(From NASA, used w/o permission.)
(The Perseverance rover’s caching strategy.)

Assuming that Perseverance lands safely — and as soon as the rover’s ‘is everything working’ checklist is finished — the rover will start using MEDA, PIXL, RIMFAX and SHERLOC.

That’s a weather station, X-ray fluorescence spectrometer and camera, ground-penetrating radar and something that uses Raman spectroscopy. All of which I plan on discussing later. Again, assuming that Perseverance lands safely.

There’s only so much lab equipment we can pack in one rover, so Perseverance will collect and store samples: leaving them in caches for later missions to collect and return to Earth.6

Picking a Landing Site: Location, Location, Location

(From JPL/NASA, used w/o permission.)
(Top three landing sites for Mars 2020 mission. (2017))

Jezero Crater may not have it all. But the former Martian lake was top choice from more than 60 candidate locations.

Landing on its now-dry river delta gives Perseverance access to at least five different kinds of rock. Plus, if there was life on Mars, that’s a spot where we may find its traces.

And some of Jezero Crater’s landforms are upwards of 3,600,000,000 years old. Even if there’s no trace of Martian life, we’ll learn more about planetary development.

That’s the good news.

The anxiety-generating news is that it’s a dangerous place to land. “Challenging,” as NASA puts it.7

I don’t envy mission planners. Prime real estate for science, like Jezero Crater, by definition isn’t the featureless and boring sort that is safe.

But getting back to good news.

Mars 2020 is smarter than earlier probes. JPL and NASA are, I figure, hoping that it’ll have a better chance at landing safely.

I hope so, too. And I figure that eventually we’ll be setting up Martian landing fields with maintenance facilities for our flying robots.

And — also eventually — scientists and technicians who prefer working in the field. Maybe some of them will decide that settling offworld makes sense. And that’s yet another topic.

Yesterday’s and Today’s News: Perseverance Landing

(From BBC News, used w/o permission.)

Nasa Mars rover: Perseverance robot heads for daunting landing
Jonathan Amos, BBC News (February 17, 2021)

The moment of truth has arrived for the US space agency’s Perseverance rover.

“…It’s got to put itself down safely on the Red Planet – a task that has befuddled so many spacecraft before it.

“But if Perseverance is successful, it has an amazing opportunity to find signs of past life on Mars.

“Never has a science mission gone to the planet with so sophisticated a suite of instruments; never has a robot been targeted at so promising a location….”

Emphasizing that last sentence. The Mars 2020 mission is high risk and high reward.

My guess is that some rewards won’t be obvious, or even known, until decades from now. Centuries, maybe.

And that, looking back, many of us will see exploring Mars as worth the risk.


NASA’s Perseverance Has Landed
Mission Updates, Mars 2020 Mission, NASA (February 18, 2021 (ca. 3:00 p.m. Minnesota time))

“Cheers erupted in mission control at NASA’s Jet Propulsion Laboratory as controllers confirmed that NASA’s Perseverance rover, with the Ingenuity Mars Helicopter attached to its belly, has touched down safely on Mars. Engineers are analyzing the data flowing back from the spacecraft.

“A postlanding briefing is expected at 5:30 p.m. EST (2:30 p.m. PST) on NASA TV and YouTube. …”

Perseverance has landed, sent back two ‘engineering camera’ pictures. The view isn’t great, partly because dust from the landing hasn’t settled yet.

It’s now 3:02 p.m. here in Minnesota. I’ll post this, and get back to following NASA coverage. “Excited” doesn’t quite fit how I feel, but it’ll do for now. Wow.


USGS Astrogeology Science Center's image: Mars 2020 landing area.
(From USGS Astrogeology Science Center, used w/o permission.)
(Mars 2020 landing area, from the US Geological Survey Astrogeology Science Center.)

This isn’t the world I grew up in.

Back then, space travel was ‘science fiction’ for most folks.

So were computers and robots.

But instead of waxing nostalgic over the ‘good old days’ — seriously, does anyone really miss cholera, polio epidemics and smallpox? — I’ll talk about Hohmann transfer orbits and why seeking truth doesn’t bother me.

Walter Hohmann described minimum-energy elliptical orbits connecting two circular orbits “Die Erreichbarkeit der Himmelskörper”/”The Attainability of Celestial Bodies.” (1925)

We don’t use Hohmann transfer orbits for navigation. None of the Solar System’s planetary orbits are circular, Hohmann’s elliptical orbits assumed that changes in speed were instantaneous, and didn’t take planetary gravity into account.

But they’re a pretty good approximation of actual spacecraft paths. Which is why Mars missions launch at about 26-month intervals and arrive within days of each other.8

There’s more to say about Earth-Mars-Earth round trips, but that will wait.

One more point, and I’m done.

Beauty, Truth and Paying Attention

Studio Foglio's Mr. Squibbs.Why doesn’t space exploration and science bother me?

Basically, it’s because I don’t have a problem with seeking truth.

In fact, I think it’s a good idea.

I also think learning about God makes sense.

We’re in a universe packed with beauty and wonders.

I figure that all truth points toward God. (Catechism of the Catholic Church, 27, 3135, 41, 74, 2500)

Paying attention to the order and beauty surrounding us will, if we’re doing it right, help us learn about God. (Catechism, 3132, 3536, 301, 303306, 311, 319, 1704, 22932296)

I’ve talked about this before. Quite a bit:

1 Mars 2020 tech:

2 CEDL, gDRT, TRN and all that:

3 Extracting oxygen:

4 Mostly Moxie, a non-lethal patent medicine:

5 First Martian helicopter:

6 Mars 2020 science:

7 Mars 2020’s destination:

8 Getting there, in theory:

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About Brian H. Gill

I was born in 1951. I'm a husband, father and grandfather. One of the kids graduated from college in December, 2008, and is helping her husband run businesses and raise my granddaughter; another is a cartoonist and artist; #3 daughter is a writer; my son is developing a digital game with #3 and #1 daughters. I'm also a writer and artist.
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2 Responses to Perseverance on Mars: February 18, 2021

  1. irishbrigid says:

    Wrong word: “Martian lake was top choice form more than 60 candidate locations.”

    The Friendly Neighborhood Proofreader

    P.S. Someone at NASA had *fun* with some of those acronyms.

Thanks for taking time to comment!