NASA's Perseverance rover sends stunning images • Hacker News Board

Re: NASA's Perseverance rover sends stunning images

#321

Post by simonh » Wed, Mar 03, 2021, 4:58 PM UTC

gambiting wrote: post #241

histriosum wrote: post #195

Earlier quoted context omitted.

My guess would be bandwidth. Every bit of bandwidth is precious, so they probably dont have the spare budget to send long audio files without obvious scientific value...

Yes, but you could record few minutes of sound in the same amount of data taken by one high res photo. I think the good question is why 18 seconds specifically.

It's just 18 seconds so far. I doubt they sent the microphone just so they could use it once, but then I doubt sending hours of audio was at the top of the priority list for the first few days of the mission.

Re: NASA's Perseverance rover sends stunning images

#322

Post by dekhn » Wed, Mar 03, 2021, 5:00 PM UTC

whatever1 wrote: post #155

Anyone has insights on how data in such volumes can be transferred from Mars to Earth in the absence of a direct link? Do the intermediate nodes have gigabytes of available storage to emit data to the next available node once it becomes visible ?

See https://www.quantamagazine.org/vint-cerfs-plan-for- building-an-internet-in-space-20201021/ for some details on projects related to this. IIRC it's store and forward.

Re: NASA's Perseverance rover sends stunning images

#323

Post by Bluestein » Wed, Mar 03, 2021, 5:01 PM UTC

UnFleshedOne wrote: post #319

comboy wrote: post #248

Earlier quoted context omitted.

> there isn't anywhere in the universe you couldn't communicate with Right, assuming you are emitting infinite amount of photons, there are no obstructions, black holes and you ignore universe expansion and GR which can make your precise enough clocks go out of sync.

"Precise enough clocks" includes handling GR and other non-destructive effects along the whole light path I assume. :)

That's one big ask :)

Re: NASA's Perseverance rover sends stunning images

#324

Post by ryandvm » Wed, Mar 03, 2021, 5:02 PM UTC

junon wrote: post #70

ryandvm wrote: post #56

Earlier quoted context omitted.

Are you really asking why we can't power your fridge with plutonium?

Do you have an answer that isn't speculation or something you concluded from a breezy stroll over to Wikipedia? Stop mocking questions. It solves nothing.

Fair enough. I probably should have dialed down the snark.

I suppose if we're looking for a Randall Munroe / "What If?" style explanation of why powering consumer equipment with plutonium is a bad idea, then it was the right question to ask.

Re: NASA's Perseverance rover sends stunning images

#325

Post by Nelkins » Wed, Mar 03, 2021, 5:07 PM UTC

I hope we start terraforming Mars in my lifetime.

Re: NASA's Perseverance rover sends stunning images

#326

Post by birdyrooster » Wed, Mar 03, 2021, 5:16 PM UTC

Nelkins wrote: post #325

I hope we start terraforming Mars in my lifetime.

I hope we figure out how to terraform Earth first

Re: NASA's Perseverance rover sends stunning images

#327

Post by asasidh » Wed, Mar 03, 2021, 5:20 PM UTC

"The Perseverance rover has initial funding to operate for one Mars year, roughly two Earth years."

So wire the rover money after 2 years ? no wonder Elon is into Bitcoin

Re: NASA's Perseverance rover sends stunning images

#328

Post by Bluestein » Wed, Mar 03, 2021, 5:20 PM UTC

WarOnPrivacy wrote: post #312

bloak wrote: post #302

Earlier quoted context omitted.

The most complex machine of the Roman era was perhaps a water organ. (I would guess that for long historical periods the most complex machines were keyboard-controlled musical instruments.)

Oh see you did it now - opened up a vacuum about ancient tech. I'll start: https://en.wikipedia.org/wiki/Aeolipile

(The question as to how - and why or why not - we could go from the Aeolipile to full blown steam engines, I've always found fascinating ...

... what other things / proceses / materials / frame of mind made the steam engine possible vs. this.

What made for an industrial revolution in the 1800's vs. the 1st century AD).-

Re: NASA's Perseverance rover sends stunning images

#329

Post by f-word » Wed, Mar 03, 2021, 5:31 PM UTC

nitrogen wrote: post #74

AnimalMuppet wrote: post #54

Earlier quoted context omitted.

What's powering Voyager is a plutonium pile. Pretty sure you don't want that in your fridge. 10 billion miles from me? Sure, knock yourself out. 10 feet from me? No way.

AKA "Not In My Back Yard." So the question stands and extends to include this: "why not?"

There's a TON of power generation alternatives that look much better both from the "trying to not give you a lot of cancer" standpoint and the "efficiency is something we care about" standpoint. Most RTGs make about 3 to 6% efficiency, while a random Amazon 100w solar panel will give you 15/22% without most of the risks.

The main reason this are used vs (or sometimes along!) other technologies is that they function rather happily in super crappy conditions we don't -unless some world-ending event happens soonish- usually have on Earth.

Re: NASA's Perseverance rover sends stunning images

#330

Post by carabiner » Wed, Mar 03, 2021, 5:35 PM UTC

berkes wrote: post #189

Looking at closeups of the Rover, I cannot help but think: are those screws, nuts and bolts? And if so, why? Why carry the weight or decreased stiffness of or by the notches, slits, threads etc. that makes screws be screwable. To a place where no-one ever will unscrew them?

Because you'd need higher weight in wall thicknesses if using weaker 3D printed aluminum instead of aluminum sheet, bar stock etc. Which actually has a coherent grain.