NASA Just Launched Its New Perseverance Rover to Mars | Hacker News Reader

NASA Just Launched Its New Perseverance Rover to Mars

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142 pointsn0pe_p0pe72 comments

Really excited about this one. It’s a sample cacher, so is the beginning of the sample return effort. It also has an in situ resource utilization demonstration involving capturing CO2 from the Martian atmosphere and splitting it into oxygen (and carbon monoxide fuel) using a solid oxide electrolysis cell. That kind of tech is critical for human missions.

And, of course, the helicopter!

>> And, of course, the helicopter!

It is cool, but is being falsely reported as the "first extraterrestrial aircraft", which it certainly is not. The Russian Vega mission had aircraft (balloons are aircraft) flying on Venus back in the 1980s.

https://en.wikipedia.org/wiki/Vega_program#Balloon

Yes, well aware of the Soviet Venus missions, including balloons. NASA is promoting it as the first extraterrestrial powered aircraft. Analogous to the Wright Brothers.

So "aircraft" is narrowed to the subset powered + heavier-than-air aircraft. But there too I would argue with NASA. NASA itself has already flown a heavier than air powered aircraft on mars! They landed the Curiosity rover using a rocket-powered "sky crane". That device was a powered aircraft. It controlled the decent of the rover, delivered it gently onto the ground, and executed an escape maneuver. That was a heavier-than-air, powered, aircraft flying/navigating/performing tasks, over Mars, in 2012.

https://science.nasa.gov/science-news/science-at-nasa/2012/3...

At most, I'll give NASA that this is the first extraterrestrial rotary winged aircraft, the first helicopter.

I would call this the first "fully-functional" or "multi-mission" aircraft. Vega was a balloon with no controls. Curiosity descent stage was a spacecraft that performed landing maneuvers. Both of these crashed into the surface as part of their mission goals. They barely could qualify as aircraft, and only in the sense that they floated in air briefly before crashing. Neither could be used for multiple missions or actually take off and land under their own power.

The balloon was airborne and transmitting data for 40+minutes. I'll be impressed if this tiny helicopter lasts that long.

No, I meant that NASA stipulated that it was the first powered flight, a nod to the Venus mission as being the first extraterrestrial (unpowered) flight.

That's cool!

Why NASA didn't opt for a balloon too for this mission?

Mars's atmosphere is very low density, so the balloon would have to be unreasonably enormous to fly anything useful. Venus, on the other hand, has an extraordinarily dense atmosphere. So dense that folks have hypothesized floating entire cities.

Is this fact the inspiration behind the floating city in Star Wars V? (Serious question)

The inspiration was the gas giants, planets with no practical surface on which to land.

Venus atmosphere is so thick light beach balls pumped with regular Earth's air would floating in it.

Mars atmosphere is so thin it's almost impossible to make a ballon float in it.

Because the atmosphere on Mars is orders of magnitude thinner (depending on altitude), making balloons a bigger challenge (and less useful in some ways).

Because they wanted to test a helicopter

And because anything that can float on the light martian atmosphere can be blown away by the light martian wind.

I think there is more reason to be excited about the microphones it is reportedly carrying than the helicopter, if it works it would be the first time we would hear the sounds of the wind in Mars.

the insight lander used its seismometer and air pressure sensors to convert the sound of the wind into audio https://www.youtube.com/watch?v=yT50Q_Zbf3s - not exactly the same, but thought you might be interested if you hadn't seen it.

Thanks for sharing.

How will the probe return the Martian samples? Is there going to be a round-trip mission to Mars in the future which will be able to take these samples back with it?

ESA and NASA are collaborating to get samples from the surface to Martian orbit, and ESA is responsible for getting them the rest of the way back to Earth. Airbus just got a big contract for the return vehicle

No, leaving them in place for possible future mission

That's neat, but I can't help but wonder how it's more cost-effective than having the possible future mission reach a scoop out once it gets there and collect its own samples.

"Hi Mars Recon 1! I'm Mars Perseverance! I brought you some decades-old rocks and dirt!"

"Uh, thanks Perseverance. I, uh, might get my own though." ;)

If they had a rover that could do all the same science and collect and return all the same samples as Perseverance, well they would send that instead of Perseverance.

The mass budget for a return-to-earth mission is tiny.

While simply scooping up some dirt and returning with it would be amazing, the potential science that could be achieved is far less than finding and collecting good samples will allow.

Neil Armstrong is still revered by scientists today because he was such a good geologist - knowing what areas to investigate and samples to collect is essential.

Perseverance will do the geologist work, and is set up for that purpose. Find, investigate, and collect samples that are likely to enable good science.

The retrieval mission can focus on the extremely difficult job of getting them back to Earth.

I have yet to hear a good explanation for this. Rendezvous on the surface of the planet sounds much more challenging than simply taking new samples, even assuming you need significant equipment to ensure you're taking the most interesting samples.

Perseverance will land using terrain-relative autonomous navigation, demonstrating fairly precise landing.

There are multiple reasons to split the mission. Perhaps the main one is that ~1 ton is approximately the upper limit of existing Mars landing technology which is enough for a powerful rover like Perseverance that can carry several sample return canisters (and live long enough to find really good samples) OR a rocket capable of returning the samples back (with just a small, basic canister retriever rover). Yeah, you could just put a sampling arm on the rocket lander, but that's a lot of wasted opportunity (heh).

Perseverance should have plenty of range, and the autonomous landing navigation tech should have sufficient precision that surface rendezvous should not be a major challenge.

Go do some research and report back to us please. I would be happy to hear what you find.

You only need to send something optimized to pick something up and launch it. You don't need to send the digging gear/packaging gear that this Rover was going to use anyway

Digging and packing gear has been demonstrated many times, and sounds way less risky and complicated than robotic rendezvous and transfer on a planet's surface, which I believe has never been done. Moreover, why not just make the digging mission and sample-return mission the same mission?

Like, was it really the case that (1) the current digging mission could not be delayed AND (2) there is little independent value for a later new digging mission AND (3) it is easier to rendezvous and transfer than just re-dig?

Robotic rendezvous isn’t particularly hard, as long as you can land nearby. Robotic rendezvous happens regularly at ISS, and being on a planet should be even easier as you don’t have to worry about orbital mechanics or the fact that in orbit, things are moving around. On the surface, speeds are low and everything is sitting on the surface so it’s basically quasistatic.

Also, except for the landing bit, it’s basically done by autonomy-assisted remote control. It’s not “Level 5 Self-Driving” or whatever.

Also, picking a random sample near the landing site is not optimal. You want to pick really good samples. A rover like Perseverance that can take years to collect the very best samples over distances of several miles is much better. Remember, we already have “random” samples from Mars in the form of Martian meteorites on Earth. We want particularly good samples.

The ISS has human operators in real time, so it's just remote operation. And ISS work still requires human intervention (with hands) for most complicated things. The only things that are done without real-time control are things that were failure prone in the past but have be mastered over years. And even then, the Russian autonomous docking system recently had major issues.

The mention of self-driving cars, orbital speed, and the suggestion of sampling near the landing site all appears to be responding to an argument I didn't make.

Most importantly, you haven't addressed my point, widely appreciated in spaceflight, that novel untested mechanisms are always one of the primary sources of risk.

I defer the decisions made by hundreds of scientists to the HN armchair general

The point of my argument is not to challenge their expertise, the point is to either understand the technical motivation or to uncover non-scientific (e.g., political) motivations.

Yes.

And not a single picture of the Rover can be seen in the article.

For the curious: https://en.wikipedia.org/wiki/Perseverance_(rover)

Aside from the drone, it's a Curiosity rover with upgraded tires (and diff instrument package). I think that is actually an incredibly exciting statement, not boring: Nasa has such high confidence in the refinement of Mars rovers that they're only making small changes now.

From what the guide at JPL said when I went on a tour there and got to see the Perseverance rover in the cleanroom, was that they simply had enough spare parts from building the Curiosity that it was easy/worth building this second one.

It's awesome, but I'd also call it a reality check if you believe that the future of space exploration is unmanned. Curiosity landed landed 8 years ago and has covered the equivalent of a day's hike (23km) for a human. It's got to stop and drill, take photos, etc, but it still probably represents only several days worth of tasks for a human.

Perseverance has better instruments, but is the same platform and weight because there's no rockets capable of putting anything larger on Mars. It's also not going to be doing anything faster than Curiosity did. The rate of improvement of these robots is really slow.

I'm really hoping the next generation of reusable/refillable rockets changes things.

While true, it's not a good argument, humans would require much more equipment, the rover is limited by the amount of weight we can put on Mars, if you use the same weight allowance that even modest manned missions to mars would require on rovers you'll get a very different coverage.

Humans are important because they can think and be in the loop where it matters most, but it's not that they'll be able to cover that much more ground. We don't have the technology to allow for a human to trek 23km on mars yet, even when we will I don't see NASA or anyone approving such a mission so now you need a vehicle capable of transporting humans, providing emergency shelter and life support, the longest single manned trip we've taken on a celestial body was about 7km on lunar roving vehicles.

Yes those covered usually around 30KM in a single mission but not in a single trip, all trips were well within visual range and well within recovery distance if need be.

The longest manned lunar rover trip was more like 15km (7.5km out and back on Apollo 17) and the limiting factor there was that the astronauts had to be ready to walk back if it broke down. If the mission called for the astronauts to walk 23km in a single trip on Mars, designing the technology for that would not be a huge leap.

I agree the extra weight required for life support and a return journey would be far greater than what the unmanned rovers need.

Starship is designed to land 100 tons of equipment, supplies and people on Mars, and to be built fairly cheaply (close to $100M each). If it can meet those performance parameters the first expeditions will include dozens to hundreds of people and thousands of tons of equipment and supplies.

And those folks will produce hundreds of times the scientific value.

> Perseverance has better instruments, but is the same platform and weight because there's no rockets capable of putting anything larger on Mars.

Actually this statement has two mistakes. First, despite Curiosity and Perseverance indeed share the platform, later is 150kg heavier (1050kg vs 899kg). Second, there are rockets, which are more performant than Atlas V 541, which launched the Perseverance [1]: Atlas V 551, Ariane 5 ECA, Long March 5, Delta IV Heavy, Falcon Heavy (expended).

[1] https://en.wikipedia.org/wiki/Comparison_of_orbital_launch_s...

How many robots could you send with the same budget (both financial and mass) required for a human mission? If a rover can do 5 days worth of human science over its liftetime, and a human mission would take 100 Billion over the course of the program to send 100 tons (approximately the cost and weight delivered to the lunar surface of the apollo program) then you could do 500 days of science, which is approximately what the human mission would be capable of. That's with less risk to human life and much more flexibility.

A NASA manned Mars mission would cost far more than $100B, because they will require transporting all fuel for return trips, and each pound of fuel will cost over $100,000 to send to Mars using cost plus contractors, ie the SLS. And that’s likely only to land a half dozen astronauts. A SLS can only accelerate 25 tons of payload to Mars intercept orbit, which means at max 10 tons to the surface..

A Mars Direct like mission, as SpaceX is planning for Starship, will send hundreds of astronauts to Mars for less than $10B by leveraging in-orbit refueling and in-situ fuel generation.

Using in-orbit refueling each Starship is designed to land 100 tons of crew, supplies and equipment on Mars.

Of course, Perserverance has an in situ resource utilization demo for making oxygen (and carbon monoxide fuel) from the atmosphere, enabling refuelable Mars rockets. Super cool.

curiosity had to deal with many firsts, like the sharp rocks puncturing its wheels at a higher than predicted rates

you want to have many of these 'firsts' moments before launching humans, as long as there's 'firsts' it's going to involve too much risk, even if you plan not returning the humans, getting some there requires a couple order magnitude infrastructure as a rover, so you don't want to lose your investment day 2 from some unforeseen accident.

of course you can't predict everything. but the fact that we're still discovering this many issues about the environment is a good indication we haven't discovered enough to get risk to a manageable level

I'm excited for Ingenuity, the Mars Helicopter Scout!

https://en.wikipedia.org/wiki/Draft:List_of_active_Martian_A...

I couldn't resist.

Why "air force" for a civilian research aircraft?

Needs rows with active and passive weapons systems plus technical specs for communications hardware.

In terms of computing, anyone knows what’s the spec and what’s the software stack like? Assembly machine codes?

Same as the Curiosity rover back in 2011:

https://en.wikipedia.org/wiki/RAD750

https://mars.nasa.gov/mars2020/spacecraft/rover/brains/

HW: 2 x RAD750

SW: I will speculate that very similar to Curiosity - https://softwareengineering.stackexchange.com/questions/1596...

If budget was not an issue is there a reason that we don't launch multiple rovers during the mars window?

Would one rover team be able to manage multiple rovers?

They did that with Spirit and Opportunity, which did cost a lot less. If money really were not an issue, I'm sure they'd like to send twin rovers again, and also pay for two rover teams, and for extra telecommunications capacity in the form of a dedicated orbiter[1] or two, and so on.

[1] https://en.wikipedia.org/wiki/Mars_Telecommunications_Orbite...

Good question. I imagine that communication infrastructure would have to be taken into consideration, but I don't know much of the details. The rover has the following capabilities for comms, but I don't know what the limits are in Mars orbit for relays:

- UHF up to 2 Mbps

- X-band High Gain 160/500 bits per second

- X-band Low Gain about 10 bits per second

https://mars.nasa.gov/mars2020/spacecraft/rover/communicatio...

There are allocations from the International Telecommunication Union for deep space communications in the S, X, K and Ka bands. This bandwidth (and parameters like transmit power of the relay spacecraft) effectively bounds how many bits per second you can get back from Mars. You can do better with optical communications and maybe some clever MIMO-like tricks.

https://en.wikipedia.org/wiki/Deep_space_bands

How do we communicate with the rovers when Earth and Mars are on opposite sides of the Sun?

Sounds like it doesn't last all that long. They have a keep-alive program running during, and then get back to work once the connection is restored:

https://www.jpl.nasa.gov/edu/learn/video/mars-in-a-minute-wh...

Relay the lasers at a Lagrange point somewhere?

If you had unlimited budget, a large stockpile of PU for the power supplies, and a dedicated DSN to not have to share time with other missions would it be possible to operate 10's or 100's of these rovers?

Not sure of the the weight but would it be possible to stack the rover payloads to send multiple rovers per launch?

Part of it is that they learn something from mission N and use that information to design the science instruments and choose the location for mission N+1. If N and N+1 launch simultaneously there's no chance for improvement in mission N+1.

Does anyone know why the Chinese probe which seems a lighter payload needs a heavy lift Long March 5 rocket, while Perseverance only requires a medium lift rocket? Is it because of some different approaches in the orbit taken to Mars?

Also how does the UAE probe's approach/trajectory to Mars.

I believe the Chinese mission actually does have more mass overall - although the rover is a lot smaller, they're also sending a large orbiter and a landing platform to deliver the rover to the surface.

That's cool. If NASA and CNSA can work the details out, they can share comms; it's always good to have more redundant comms solutions in orbit.

Unfortunately (or fortunately depending on who you ask) NASA is very restricted in what it can do with China, so probably not. But NASA does utilize ESA's Trace Gas Orbiter in addition to their own Mars orbiters for relay operations.

https://en.wikipedia.org/wiki/Chinese_exclusion_policy_of_NA...

I heard CNSA is also planning to use an ESA orbiter as backup comms relay, besides using the ESA ground tracking stations as well.

Maybe they're sending something else alongside?

Tianwen-1: 5000kg/11000lb

Perseverance: 1025kg/2300lb

The Perseverance mass is just for the rover, but there's a few other components that get it to Mars and on to the surface (the cruise stage, sky crane, etc).

I can't seem to find the Mars 2020 numbers but for MSL (which should be similar) the overall launch mass was 3839 kg of which 899kg was the Curiosity rover itself.

It appears Tianwen rover is only about 200-300 kg, but their orbiter is massive at 3000+ kg.

The rovers are very advanced. And they are coming back!! That's a major plus.

Coming back?

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