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Drzhivago138 t1_j5v7fy6 wrote

Reply to comment by electric_ionland in Why do sample return missions such as OSIRIS-REx use their own reentry vehicles instead of just going to the space station for pickup and return with ISS equipment? by PromptCritical725

>They just slam into the atmosphere and let it do all the braking for free.

It helps that unmanned probes don't have to worry about pesky things like crew survivability during reentry.

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crazunggoy47 t1_j5wu80j wrote

In a pinch, they can also lithobrake!

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DoubleDot7 t1_j5wuusq wrote

Does that mean letting the ground do the breaking for free?

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danielrheath t1_j5wxivw wrote

Yes, as in "Craft underwent rapid unplanned disassembly after an unintentional lithobraking maneuver"

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Controlled01 t1_j5xofup wrote

Is that how they described that Martian lander that plowed into the dirt all those years ago

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gandraw t1_j5xqxmn wrote

That's why it's important to remember the difference between aerobraking and areobraking when you tell the NASA engineers to build something.

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Sergio_Morozov t1_j5y2d4y wrote

Did you mean aerobraking and aerobreaking? If so, are YOU a NASA enigeer perchance?

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gandraw t1_j5y2mk6 wrote

Ares is the greek name of Mars, so "areobraking" is the equivalent of "geobraking" and technically means "braking using the Mars surface"

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anomalous_cowherd t1_j60adde wrote

Nice, I'll use that when I want to outnerd somebody. (Said in an affectionate way, I like outnerding people!)

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tdmonkeypoop t1_j63v923 wrote

Ok.. Socrates!! Dudes over here playing 4D chess like he's dust in the wind or something

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LionST1 t1_j5xbury wrote

Using elastic deformation of structural materials and the landing zone to rapidly dissipate kinetic energy, very clever.

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Equoniz t1_j5xh962 wrote

I’m pretty sure lithobraking often entails deformation significantly past the elastic limits of the materials involved.

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LetterBoxSnatch t1_j5z15vc wrote

I suppose it depends on just how elastic your definition of “elastic” is…the materials may still be capable of reattaining their prior size and shape, given enough energy and engineering dollars

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oz6702 t1_j5xl67o wrote

This is the kind of engineering we're trying to perfect over at /r/KerbalSpaceProgram

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Iz-kan-reddit t1_j5xlwoe wrote

> Does that mean letting the ground do the breaking for free?

I'd correct you with braking, but breaking is also correct in it's own way.

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NetworkLlama t1_j5xeh9a wrote

That actually happened with the Genesis mission to collect samples from the solar wind. It hit the atmosphere at 11 km/s, but after slowing down, the parachutes never deployed. It impacted the ground at 86 m/s, contaminating most but not all of the collectors, and some of the science was salvaged.

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overlydelicioustea t1_j5y8rvv wrote

mars sample return mission will not do this in a pinch, its the planned reentry mode to just have the container be sturdy enough and , well, just let it hit the deck.

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BaldBear_13 t1_j5ww4tg wrote

If Sci Fi movies taught me anything, it's that when a probe returns from uncharted reaches of deep space, lack of survivability is a plus, and is called sterilization.

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dWintermut3 t1_j5xt71k wrote

NASA has a specialist for that actually, with the most badass job title in history of "planetary protection officer".

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SirCB85 t1_j5xv9yr wrote

Wait, my understanding of their job description was that they actually responsible for making sure WE don't contaminate let's say Mars before we are really really really sure that us contaminating it doesn't destroy any indigenous life we might like to study before we annihilate it?

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dWintermut3 t1_j5xw7in wrote

yes, that's a very important job of the PPO. but my understanding is as the staff's highest-ranked microbiologist control of potential alien lifeform risks to earth is also in their purview.

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b33r_engineer t1_j5yifcj wrote

That’s what they want you to think, yes…

(It’s also true, but they do both)

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BaldBear_13 t1_j5yi0tj wrote

are they issued a flamethrower? A cool suit? A memory wipe device?

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