Can we please send a submarine to Enceladus now?

[KerikBalm]

https://www.nature.com/articles/s41550-021-01372-6?utm_medium=affiliate&utm_source=commission_junction&utm_campaign=3_nsn6445_deeplink_PID100052171&utm_content=deeplink#article-info

We really need to determine if it has life 

 

[DDE]

LOL, I posted roughly the same news into the pinned thread at the top.

The recent Venus detour makes me skeptical.

Also, the planetary protection peoppe are gonna have a fit.

Edited July 8, 2021 by DDE

[MKI]

What would a submarine mission to Enceladus even look like?

How would it get there, get into the ocean, and report back its findings?

What sort of risks involved in terms of just executing that mission from what we know now? (like digging through all the ice to get to the ocean)

 

 

 

[SOXBLOX]

Well, first you'd need nuclear power, so you have to wait on NASA to scrounge together the plutonium. Then you have to launch this (presumably large) probe on something. Then, it would orbit Enceladus, map it in high-resolution, select a landing site where the crust is thought to be thinnest, and set down the submarine, which would slowly melt its way through the ice.

Maybe you could send two missions, a mapper/relay probe and the sub + lander.

[DDE]

5 hours ago, SOXBLOX said:

Well, first you'd need nuclear power, so you have to wait on NASA to scrounge together the plutonium.

I think we'd be looking at HEU, not plutonium here. Really reminds me of the sporadic rumor that reactor techies from Afrikontov were somehow involved in the development of this thing:

I've never been able to verify it despite it being claimed as OSINT.

[kerbiloid]

A nukikaze.

It's easy to melt down and dive, but how to return up or at least send a report?

[KerikBalm]

9 hours ago, MKI said:

What would a submarine mission to Enceladus even look like?

Rocket launches a payload to Saturn intercept for about  7,700 m/s from LEO.

Then you spend about another  3800 m/s to get an Enceledus intercept, and about another 4,600 to capture and land on Enceledus (landing from low orbit taking only about 160 m/s), total would be 16,000 m/s from LEO. You could probably shave a few thousand m/s using gravity assists from a moon such as Titan, and maybe from Jupiter if the launch window is right.

I'm thinking the SpaceX spaceship would be a good candidate for the launch vehicle, since the probe will need multiple stages and a lot of dV.

9 hours ago, MKI said:

How would it get there, get into the ocean, and report back its findings?

Gets there by rocket, from low Enceledus orbit is trivial (160 m/s needed, gravity is only 0.113 m/s² at the surface)

Getting into the ocean would be harder, likely you'd try to enter via a geyser. An RTF could provide the heat to melt through

Trails a cable, send result by radio from an emitter on the surface

9 hours ago, MKI said:

What sort of risks involved in terms of just executing that mission from what we know now? (like digging through all the ice to get to the ocean)

Risks? spending a lot of money for no result.

Contaminating a habitable environment.

If we find that there is no life, and we bring microbes that could survive there (unlikely, the probe would need to be contaminated with microbes suited to hydrothermal vents on Earth), I consider that a bonus: we've made Earth life interplanetary and colonized a new world with life (again, only a bonus if Enceledus is actually sterile).

 

[kerbiloid]

1 hour ago, KerikBalm said:

to enter via a geyser.

It's a labyrinth of cracks in the ice, not a vertical pipe.

1 hour ago, KerikBalm said:

Trails a cable

Which is 40+ km long and should get frozen into the water ice, once  the probe has passed a little lower.
By the water ice, which is expanding while freezing, so 40 km of mechanical deformations. Should be a thick cable.

1 hour ago, KerikBalm said:

send result by radio from an emitter on the surface

If for some reasons the cable is still not broken.
Otherwise - sending results from the salt water under 40 km of ice - no chance.

***

I like when the people who deorbit Galileo and Juno into the Jupiter to prevent the contamination of a Jup's moon with a 500 kg probe, at the same time don't hesitate with sending a barrel of nuclear fuel into a super-corrosive hot salt water on same moon.

[RCgothic]

The planetary protection stuff isn't ultimately because we don't want to spread life to other planets. If we're going to live in other worlds they're going to get contaminated, and any effort to prevent that is ultimately futile. The reason we currently go to such lengths is so that future probes don't go "we've discovered native life!" when in actual fact they're discovering the results of previous probes. 

 

But starship could definitely deliver something hefty to Enceladus. It's 7300m/s to Saturn and 3600m/s to Enceladus from LEO. That's ~11km/s total.

DeepSpace!Starship probably weighs about 60t dry and pushes 100t payload and 380s ISP. With 1200t of propellant it can get to Enceladus from a refuelling somewhere around GTO. With stretched tanks and a transhipped payload the refuelling orbit wouldn't even need to be that high.

 

So that gives 100t to an intercept. 4500m/s to a landing. Lander would probably need to have hypergolic propulsion with ~310s ISP. That'd take a large propellant fraction, but with 100t wet it's still probably 20t landed.

 

Could do a lot with 20t landed.

 

 

Edited July 9, 2021 by RCgothic

[DDE]

27 minutes ago, RCgothic said:

The planetary protection stuff isn't ultimately because we don't want to spread life to other planets. If we're going to live in other worlds they're going to get contaminated, and any effort to prevent that is ultimately futile.

Unfortunately, at least some people (i.e. Zubrin) claim PP has become an industry unto itself, losing sight of any goal and becoming just an obstacle to doing any worthwhile astrobiological research and testing.

But then Zubrin appealed to panspermia as evidence for contamination either being a non-issue, or a long-done deal, in the same article.

[KerikBalm]

3 hours ago, RCgothic said:

The planetary protection stuff isn't ultimately because we don't want to spread life to other planets. If we're going to live in other worlds they're going to get contaminated, and any effort to prevent that is ultimately futile. The reason we currently do to such lengths is so that future probes don't go "we've discovered native life!" when in actual fact they're discovering the results of previous probes. 

Of course. It is for 2 reasons:

1) if there is life there, we don't want to destroy it (at least not before we have a change to learn more about it). Our bacteria and Archea may well cause an ecological collapse and destroy native life

2) If we do contaminate it, our own life could make identifying native life very difficult.

In the case of Enceladus, I doubt there is any panspermia issue: if we find life like ours there, its not native.

Even if there did happen to be life on Enceladus with a common origin with life on Earth, if we sent a small sequencing machine, the nucleic acid sequence should be able to tell us if it is alien or not.

 

This mission concept seems pretty good to me:

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

 

Edited July 9, 2021 by KerikBalm

[kerbiloid]

Still wondering, how do they imagine a 40 km long cable passing throw the unstable ice layers without breaking.

I would expect that any study of the underice oceans will begin from a human expedition, drilling a classic well, installing the well casing, and passing an autonomous drone.

***

Another option.

A bullet-shaped armored probe is equipped with a fast-neutron reactor (inside the bullet-like hull).

It is equipped with an autonomous biochemical laboratory to autonomously find some life.

Spoiler

Distinguishable from the remains of the human-blooded mosquito under the cover which died from vacuum suffocation, and fingerprints of a cheeseburger on the truss, of course.

Otherwise we can think that Enceladus is inhabited by cows, mosquitoes, tomatoes, and salad. In addition to humans.

First it uses this reactor as a nuka-engine core, to accelerate from the Earth orbit, reach the Saturn system, and land on the Enceladus.

After landing, it melts the way by the same reactor, and slides down thanks to its bullet shape.

On reaching the subice ocean, it sinks and explores the bottom.

Still lying on the bottom, it decides if the life is found or not.

If the life is found, it decouples the armored hull as a ballast, comes up to the ice ceiling and makes the reactor core supercritical, so it explodes.

If the life is not found, it explodes right on the bottom, without coming up. (Anyway, nothing to look at there).

So, by the explosion depth, the surface sensor can get the probe's conclusion, and send this info to the Earth (just one bit - y/n).

A bonus: the isotopes from the exploded probe reactor will flow around the ocean, so later we can study the pattern of the underice oceanic flows.

Edited July 9, 2021 by kerbiloid

[KerikBalm]

14 hours ago, kerbiloid said:

Still wondering, how do they imagine a 40 km long cable passing throw the unstable ice layers without breaking.

The mission that I linked doesn't, it only aims to go under the ice far enough that more complex organics wouldn't be broken down by radiation and such.

Stuff is coming out of geysers, you just need to sample that while it is still in good condition.

[Exoscientist]

 Thanks for the very interesting news clip. It wouldn’t take a nuclear mission to land on Enceladus. NASA is planning an SLS mission to Europa, and the SLS could also reach Enceladus with a lander.

 Actually, a lander mission to Europa could be accomplished much more cheaply using the Falcon Heavy:

Low Cost Europa Lander Missions.                                                                                       https://exoscientist.blogspot.com/2015/02/low-cost-europa-lander-missions.html

 Likewise a lander mission to Enceladus, of smaller size, could be mounted using the Falcon Heavy.

      Robert Clark

Edited July 10, 2021 by Exoscientist

[Gargamel]

19 hours ago, kerbiloid said:

Still wondering, how do they imagine a 40 km long cable passing throw the unstable ice layers without breaking.

Well luckily enough, we do have some analogous test beds here on earth we can use.   Drop the proposed probe onto one of glaciers of Antarctica, have it delve down a bit, make a right turn at Albuquerque, and head over 40km or so through the glacier and have it surface somewhere else.   That way we can recover the hazardous material and handle it properly, and the shifting ice should simulate  conditions they'll encounter heading down.   At the very least it'll give them a test bed to work the problem.    And anything lost to the glacier can be recovered in a few centuries/millennia when it gets spit out the other end :).

With heavy lift capacity coming back into practical consideration, a conventional drilling rig might also be feasible.  It'll require a number of automated resupply missions to bring more drilling pipe to the rig. 

[kerbiloid]

44 minutes ago, Gargamel said:

It'll require a number of automated resupply missions to bring more drilling pipe to the rig. 

Yes, pipes and rig. Not a lonely probe, but a mining base.

***

Upd.

No need in explosion.

The probe should drop the bullet-shaped hull, come up to the ice ceiling, run the reactor at full power, and melt a vertical well through the ice.

Then either surface, or release a floater with samples.

Edited July 10, 2021 by kerbiloid

[JoeSchmuckatelli]

On 7/8/2021 at 6:33 PM, MKI said:

What would a submarine mission to Enceladus even look like?

How would it get there, get into the ocean, and report back its findings?

What sort of risks involved in terms of just executing that mission from what we know now? (like digging through all the ice to get to the ocean)

 

 

 

There was a TV show not long ago featuring James Cameron and some NASA folks talking about how to do it. 

Basically you get a melt probe going with the sub inside.  It has to lay a relay antenna cable and won't be able to return b/c the hole is going to refreeze behind the probe. 

Once in the ocean the melting bodies drop away and the probe miraculously discovers life on the first try. 

Everyone gets briefly famous, lands tenured jobs at elite universities and settles in to argue with other professors and sneer at students for the rest of their careers 

Edited July 10, 2021 by JoeSchmuckatelli

[Exoscientist]

There are underwater acoustic systems that can communicate underwater:

https://dosits.org/people-and-sound/communication/how-is-sounds-used-to-transmit-data-underwater/
 

 Robert Clark

[DDE]

14 minutes ago, Exoscientist said:

There are underwater acoustic systems that can communicate underwater:

https://dosits.org/people-and-sound/communication/how-is-sounds-used-to-transmit-data-underwater/
 

 Robert Clark

Yes, but they have limited range, and only work in water, so that doesn't solve the wire problem.

Still, the Vityaz is a good model: in theory it went into the Mariana Trench autonomously, without a tether, but in practice we know from procurement documents there's a companion tethered probe communicating with the sub via acoustic modem.

So we still need a 40 km wire through the ice.

[kerbiloid]

Spoiler

It passed 12 km through the rock, so would pass 40 km through the ice.

But it's not a probe. It's big and needs people.

On the other hand, it gives a purpose for a ground base.

[JoeSchmuckatelli]

1 hour ago, DDE said:

So we still need a 40 km wire through the ice

Fairly sure we did something like that with telegraph back when most people rode horses.  Although I think the Atlantic is a bit wider than 40km

49 minutes ago, kerbiloid said:

It passed 12 km through the rock, so would pass 40 km through the ice.

what is "it"?

[kerbiloid]

13 minutes ago, JoeSchmuckatelli said:

what is "it"?

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

https://translate.google.com/translate?hl=&sl=ru&tl=en&u=https://ru.wikipedia.org/wiki/Кольская_сверхглубокая_скважина

Edited July 10, 2021 by kerbiloid

[JoeSchmuckatelli]

Quote

Microscopic plankton fossils were found 6 kilometers (4 mi) below the surface

 

Cool!

[SOXBLOX]

Altitude: -21000 ft.