Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Massive Martian dust storm endangers NASA rover

nature.com

Post reply on HN
Print view View original

31–40 of 54 posts

Re: Massive Martian dust storm endangers NASA rover

#31

Post by TeMPOraL »

mabbo wrote: post #8

I'm intrigued by what research and plans have been made for how Martian colonists will deal with this sort of problem. I'm guessing solar won't be enough to keep a colony going. Wind power, even in a dust storm, wouldn't be possible because the air is so thin. Nuclear of some kind seems the only other option.

> Wind power, even in a dust storm, wouldn't be possible because the air is so thin.

From what I've read around the web, it actually would be possible. The efficiency would be around 10% of an equivalent wind turbine on Earth, but it has one thing in its favor: you could construct them with mostly local resources even at early stages of a Mars colony. PV cells are too high-tech for that, they would have to be shipped from Earth.

https://space.stackexchange.com/a/5669

https://www.youtube.com/watch?v=0xtW7g4R_vs

Re: Massive Martian dust storm endangers NASA rover

#32

Post by Tepix »

starik36 wrote: post #11

I am a bit confused by the "Massive" statement. I understand that Mars has barely any atmospheric pressure, therefore, any "Massive" storm would be a gentle wind. If fact, Andy Weir, the author of the "Martian", called the beginning of the book where the hero gets stabbed by a metal rod during the massive storm a complete fabrication for the purposes of the story and impossible in real life.

It's only letting 0.002% of sunlight through.

Re: Massive Martian dust storm endangers NASA rover

#33

Post by InclinedPlane »

starik36 wrote: post #11

I am a bit confused by the "Massive" statement. I understand that Mars has barely any atmospheric pressure, therefore, any "Massive" storm would be a gentle wind. If fact, Andy Weir, the author of the "Martian", called the beginning of the book where the hero gets stabbed by a metal rod during the massive storm a complete fabrication for the purposes of the story and impossible in real life.

The endangerment part comes not due to the wind but from the dust, which blocks out the sun remarkably effectively and for extended periods of time. This is an existential threat for a solar powered probe. Opportunity won't get blown over, knocked around, nor impaled by a metal rod, but it will be (has been already) starved of power. There are key elements of the rover which require active heating, the rover is fully capable of "freezing to death" if it spends to long without power.

Re: Massive Martian dust storm endangers NASA rover

#34

Post by zaarn »

elihu wrote: post #15
mabbo wrote: post #8

I'm intrigued by what research and plans have been made for how Martian colonists will deal with this sort of problem. I'm guessing solar won't be enough to keep a colony going. Wind power, even in a dust storm, wouldn't be possible because the air is so thin. Nuclear of some kind seems the only other option.

The article doesn't say what the exact power drop is, but it appears to have been at least 75%: > Within days, Opportunity saw sunlight dimming as atmospheric opacity — a measure of how much dust is in the air — soared. The rover’s energy production dropped by half over the course of 2 days, and then half again in a single day, Callas said during a media briefing on 13 June. Aside from nuclear, some reasonable mitiga…

Overprovisioning probably won't help.

The power drop isn't 75% it's nearly 100%. The last image transmitted is pitch black only the camera's sensor introducing some noise during the long exposure to be visible.

The mitigation is either "lots of batteries" or "have a (nuclear) generator and power down" because solar will not produce anything under the currently present conditions.

(Well not "nothing", it's generating a couple milliwatts, enough to drive the rover's internal timer so it can periodically check if it's charging batteries)

Re: Massive Martian dust storm endangers NASA rover

#35

Post by zaarn »

scrumbledober wrote: post #5
seccess wrote: post #3

Do dust storms only occur on planets with an atmosphere? And does their severity depend on how dense the atmosphere is?

IANAAstronomer but I would imagine the atmosphere is necessary for both the suspension of dust particles and the propulsion of dust particles.

Dust particles achieving orbital velocity would be sufficient too (small moons, this is possible)

Re: Massive Martian dust storm endangers NASA rover

#36

Post by jagger27 »

SECProto wrote: post #29
elihu wrote: post #15

Earlier quoted context omitted.

The article doesn't say what the exact power drop is, but it appears to have been at least 75%: > Within days, Opportunity saw sunlight dimming as atmospheric opacity — a measure of how much dust is in the air — soared. The rover’s energy production dropped by half over the course of 2 days, and then half again in a single day, Callas said during a media briefing on 13 June. Aside from nuclear, some reasonable mitiga…

Exactly this - giant solar farm for rocket fuel production, turn it off at night, turn it down or off during dust storms. Rocket fuel could be used during these lulls (nights/storms) to provide power, maybe recapturing the exhaust gases as pure feedstock. edit - batteries might be the better option for overnight, but would have serious mass penalty to use for long term backup power. Using fuel as storage is simple so…

Power from combustion seems like a bit of a tough sell in an environment severely lacking in O2. Then you also need to bring some sort of high efficiency engine (probably an LNG turbine) with you too with an appropriately sized generator. Capturing exhaust gasses is a neat idea, but now you need to bring compressors and high pressure storage tanks with you.

Re: Massive Martian dust storm endangers NASA rover

#37

Post by zaarn »

jagger27 wrote: post #36
SECProto wrote: post #29

Earlier quoted context omitted.

Exactly this - giant solar farm for rocket fuel production, turn it off at night, turn it down or off during dust storms. Rocket fuel could be used during these lulls (nights/storms) to provide power, maybe recapturing the exhaust gases as pure feedstock. edit - batteries might be the better option for overnight, but would have serious mass penalty to use for long term backup power. Using fuel as storage is simple so…

Power from combustion seems like a bit of a tough sell in an environment severely lacking in O2. Then you also need to bring some sort of high efficiency engine (probably an LNG turbine) with you too with an appropriately sized generator. Capturing exhaust gasses is a neat idea, but now you need to bring compressors and high pressure storage tanks with you.

O2 isn't the only way to do combustion. There is also a fair few of autooxidizing materials (monopropellant) which require nothing but a spark to burn up, no oxidizer necessary.

But like with O2, it's all dangerous to contain as it easily burns without much options to extinguish (esp. Flourine Compounds are nasty and some will burn up sand, fireblankets, water and your fire extinguisher)

Re: Massive Martian dust storm endangers NASA rover

#38

Post by azernik »

jagger27 wrote: post #36
SECProto wrote: post #29

Earlier quoted context omitted.

Exactly this - giant solar farm for rocket fuel production, turn it off at night, turn it down or off during dust storms. Rocket fuel could be used during these lulls (nights/storms) to provide power, maybe recapturing the exhaust gases as pure feedstock. edit - batteries might be the better option for overnight, but would have serious mass penalty to use for long term backup power. Using fuel as storage is simple so…

Power from combustion seems like a bit of a tough sell in an environment severely lacking in O2. Then you also need to bring some sort of high efficiency engine (probably an LNG turbine) with you too with an appropriately sized generator. Capturing exhaust gasses is a neat idea, but now you need to bring compressors and high pressure storage tanks with you.

If you have locally manufactured fuel that can be used in a rocket, that fuel is going to include an oxidizer; e.g. the SpaceX plan is to manufacture methalox (methane + liquid oxygen) and store both of them.

Re: Massive Martian dust storm endangers NASA rover

#39

Post by azernik »

TheSpiceIsLife wrote: post #18
credit_guy wrote: post #12

Earlier quoted context omitted.

Maybe the Kilopower reactor [1] [1] https://en.m.wikipedia.org/wiki/Kilopower

Summary of the linked Wikipedia entry: a nuclear heat source driving a Stirling Engine connected to a regular electric generator. A test reactor has been constructed, called KRUSTY or Kilopower Reactor Using Stirling Technology. It is designed to produce up to 1 kilowatt of electric power and is about 6.5 feet tall (1.9 meters).[12] The goal of the KRUSTY experiment is to closely match the operational parameters that…

A quibble - in space applications, "nuclear heat source" makes me think a radioisotope thermal generator (i.e. a lump of an unstable isotope decaying naturally). That's what's used on the Curiosity and Mars 2020 rovers. Kilopower, on the other hand, is a for-real, critical-mass nuclear reactor.

Re: Massive Martian dust storm endangers NASA rover

#40

Post by hurrrrr »

citrablue wrote: post #27
elihu wrote: post #17

Earlier quoted context omitted.

As you say, direct damage from wind isn't a major risk on Mars, contrary to the book. However, dust storms do happen, and according to the article they can affect huge areas and block out most of the sunlight.

Is the idea that this one lasts long enough that it deposits sand on my friend's panels, and they doesn't have enough backup juice by then to move/clean it off?

From what I heard buildup on the panels isn't that big a deal because the wind also blows it away. But if sunlight is cut off too long the battery becomes empty and the heaters won't work anymore. So it would literally freeze to death.
Post reply on HN