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The Mars Helicopter Is Online and Getting Ready to Fly

universetoday.com

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Re: The Mars Helicopter Is Online and Getting Ready to Fly

#231

Post by feralimal »

KuiN wrote: post #227
feralimal wrote: post #219

The mars atmosphere is equivalent to 120,000 feet. The record altitude for a helicopter on earth is 40,820 feet. How are helicopters able to fly so high on Mars? Also, parachutes do not open when the altitude is greater than 15,000 feet. How was the rover able to land at all with parachutes, in an atmosphere equivalent to 120,000 feet?

Phase 1 of the landing used parachutes to bleed off speed, but they aren't able to slow it enough for a soft landing. So a Skycrane was used for the second phase / touching down. The blades on Ingenuity are larger (relative to the rest of the vehicle) and spin much faster than would be required on Earth.

Parachutes cannot open at 15000 feet on earth - the air pressure is not there.

Why do they open at an air pressure equivalent of 120000 on Mars?

And even if they did open, they would only be able to carry a miniscule weight.

You realise that in a pure vacuum, a feather drops as quickly as a ball bearing?

Re: The Mars Helicopter Is Online and Getting Ready to Fly

#232

Post by londons_explore »

jessriedel wrote: post #164
londons_explore wrote: post #70

Earlier quoted context omitted.

Many types of bit error are not recoverable without a full system reset. It isn't a matter of a simple "this bit in ram got corrupted", but more "this floating point unit has got into a state where it will not produce a result, and will therefore hang the entire processor". Therefore boot time becomes critical - if you end up rebooting due to bit errors multiple times per second, you can't afford to wait for Linux to…

This is a problem with floating point operations happening at a lower level than the error correction you're imagining. In principle, that's not at all necessary. Are you arguing that it's infeasibly expensive to design a chip with operations that are error correctable?

It's possible - but you'll end up reinventing nearly every step of the IC design process, which will cost a lot.

Re: The Mars Helicopter Is Online and Getting Ready to Fly

#233

Post by chriskanan »

I'm very excited for this. When I was working at JPL 7 years ago they were still trying to get approval, and now they get to test it out.

I'm even more excited for the Dragonfly mission with a flying drone on Titan, but that's a long time to wait: https://en.m.wikipedia.org/wiki/Dragonfly_(spacecraft)

I wish we could fund NASA more, make it more risk tolerant, more agile, and more efficient. The Titan boat drone to explore the lakes, last I heard, couldn't be scoped due to resources. Working there requires great patience.

Re: The Mars Helicopter Is Online and Getting Ready to Fly

#234

Post by erklik »

chriskanan wrote: post #233

I'm very excited for this. When I was working at JPL 7 years ago they were still trying to get approval, and now they get to test it out. I'm even more excited for the Dragonfly mission with a flying drone on Titan, but that's a long time to wait: https://en.m.wikipedia.org/wiki/Dragonfly_(spacecraft) I wish we could fund NASA more, make it more risk tolerant, more agile, and more efficient. The Titan boat drone to e…

> I wish we could fund NASA more, make it more risk tolerant, more agile, and more efficient. The Titan boat drone to explore the lakes, last I heard, couldn't be scoped due to resources. Working there requires great patience.

I wonder if funding NASA more would mean that the "inventive" ideas get reduced. The limitation of NASA's funding has meant that they've produced ideas and technologies to cover that shortfall in even cheaper ways than possible before, and that might be reduced with a much large budget.

Re: The Mars Helicopter Is Online and Getting Ready to Fly

#235

Post by dredmorbius »

zhoujianfu wrote: post #204
ChuckMcM wrote: post #150

Earlier quoted context omitted.

And given the density of Venus' atmosphere, here is a fun thought experiment. It may be possible to make 'titanium' balloons for longer term operation. The would work by creating the balloon envelope on earth, have a sealing mechanism that you activated in orbit so they had vacuum inside. And then drop them into the atmosphere. Same idea a glass floats on fishing nets[1] except with titanium (so they can withstand th…

Does anybody have any thoughts on how feasible it would be to make a metal “vacuum sphere” that floated in earth’s atmosphere? That’d be pretty cool! How huge would it have to be? Would it have to be made of titanium? Aluminum? Stainless steel? How good are those materials at withstanding a vacuum (or partial vacuum) if the diameter was say... 50m? I feel like at some size it must work, as the volume of air displaced…

The concept is known as a "vacuum airship". TL;DR: Materials aren't strong enough past very trivial volumes.

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

This is a plot element in Neal Stephenson's The Diamond Age, as well as several other fictional appearances (Edgar Rice Burroughs, Azhar Abidi, Peter Watts, and Iain M. Banks all use the trope).

There are no materials known with sufficient strength to withstand compressive and buckling forces. Not even diamond.

Lightweight stiff structures (honeycomb, something resembling aerogel, perhaps) are other options, but seem unlikely as well.

Gas-filled airships or balloons benefit from the fact that low-density gasses (by either chemical composition or temperature in the case of hot-air balloons) exert a countervailing pressure to balance atmospheric pressure, but with a lower mass, hence providing buoyancy. The internal pressure actually provides some (or much) of the structural rigidity of most airship variants. Any vacuum airship would have to make up for this factor, again, increasing strength (and material mass) requirements.

Re: The Mars Helicopter Is Online and Getting Ready to Fly

#236

Post by Daho0n »

tempestn wrote: post #216
dal wrote: post #105

Earlier quoted context omitted.

The moon is not a planet.

Technically the moon is a dwarf planet, as it has sufficient gravity to form itself into a spheroid shape, but it has not cleared its orbit.

It's Pluto all over again!

Re: The Mars Helicopter Is Online and Getting Ready to Fly

#237

Post by Daho0n »

erklik wrote: post #234
chriskanan wrote: post #233

I'm very excited for this. When I was working at JPL 7 years ago they were still trying to get approval, and now they get to test it out. I'm even more excited for the Dragonfly mission with a flying drone on Titan, but that's a long time to wait: https://en.m.wikipedia.org/wiki/Dragonfly_(spacecraft) I wish we could fund NASA more, make it more risk tolerant, more agile, and more efficient. The Titan boat drone to e…

> I wish we could fund NASA more, make it more risk tolerant, more agile, and more efficient. The Titan boat drone to explore the lakes, last I heard, couldn't be scoped due to resources. Working there requires great patience. I wonder if funding NASA more would mean that the "inventive" ideas get reduced. The limitation of NASA's funding has meant that they've produced ideas and technologies to cover that shortfall…

I believe so. Funding competitors would likely yield better results, unless one is looking for US results versus results overall of course. A lot of very exciting missions are from other space agencies these days, which is great!

Re: The Mars Helicopter Is Online and Getting Ready to Fly

#239

Post by SideburnsOfDoom »

endymi0n wrote: post #96
julienchastang wrote: post #93

Fun fact: This is not the first time a space program has flown on another planet. The Soviets launched weather balloons on Venus during the Venera missions [1] [1] https://en.wikipedia.org/wiki/Vega_program#Balloon

This is so cool, I didn‘t know about these yet and I‘d call myself a space buff... Speaking of flight and picking the nits here — looks like Wikipedia also isn‘t completely correct here: > It is planned to make the first powered flight on any planet beyond Earth ...arguably the first _powered_ flights were done by the sky cranes of Opportunity and Perseverance

Powered? definitely.

But Flight? A rocket has no fixed or rotating wing providing lift, so maybe not.

Re: The Mars Helicopter Is Online and Getting Ready to Fly

#240

Post by Daho0n »

shellfishgene wrote: post #211
jefft255 wrote: post #2

I am incredibly excited for this. Can believe how nervous the control engineers must be for this. Not sure what quality of the footage to expect from this.

I was also excited about it, however an article critical of various points of Mars 2020 damped this quite a bit [1 (in German)]: Does the drone actually have any scientific relevance? I'm even doubtful it answers relevant engineering questions. I mean, it was tested in a pressure chamber already simulating mars atmosphere and gravity, we know it will work. The only question seems to be: Will it fail because of some e…

I do not agree at all that it is not useful but even if true the PR in itself is likely worth it, both for getting more attention to NASA (IE. budgeting) and for sparking ideas and dreams.
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