Europa

[Asbo Zaprudder]

Obviously, Earth was never encased in a global shell of ice.

The Earth might have twice been completely or partly ice covered for an extended period of time around 650 Mya and 2400 Mya.

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

 

[2takesfrakes]

Yes, we're all aware of the Ice Age(s). Earth having glaciers at tropical latitudes is not the same as being globally entombed in a casing of ice kilometers thick, billions of kilometers away from the sun and scaled down to about a quarter of its planetary size, anyway.

 

[Asbo Zaprudder]

I think it's worth sending a few probes to Europa, Titan, Enceladus, and Ganymede to look for evidence of biological activity or precursors thereof. I agree about not returning samples to Earth at this stage. Although matter has been exchanged between bodies in the solar system ever since its formation, let's not take unnecessary risks until we can evaluate the level of risk.

 

[Doom Shepherd]

Would an organism with an alien biochemistry even be able to infect something with ours? That's something we're going to need to know eventually.

 

[Asbo Zaprudder]

We might not even be able to detect a sufficiently alien biochemistry as being such. However, we might well be as toxic or harmful to it as it to us. Even if the DNA structure and nucleotides were the same, there's no guarantee that the messenger RNA codons would map to the same amino acids or stop/start instructions for building proteins.

 

[2takesfrakes]

Bottom Line? Alien life has to be treated as a Bio-Hazard. All of the precautions involved in dealing with such material have to apply. And that's just a place to start. The International Space Station MUST be the first step in a Return Sample mission process, before it's sent directly to the Earth for study.

"Oh! But that's a logistical nightmare, involving Station ..." Well then, NASA, you're just going to have to figure it out. Also, any probe doing the actual sampling could not ensure a Clean Catch. The very container the microbes would be in would likely become contaminated, on the outside. It's best to risk 7 astronauts in orbit, than 7 billion on the planet. Personally, I don't believe Life is there, but even the remotest possibility demands that proper measures be taken.

 

[Asbo Zaprudder]

Returning samples to Earth requires significant delta-V to escape both Europa's and Jupiter's gravity wells, to enter LEO and then to rendezvous with the ISS. Aerobraking in the Earth's atmosphere to reduce velocity would be out of the question as it runs the risk of contamination if the heat shield fails.

Delta-V map of the solar system

 

[publiusr]

I wounder if a redesigned JIMO might be able to get back out from Jupiter, perhaps using gravity assists for the moons and slowly building up speed. That or it could deploy a smaller spacecraft with only the sample that could be caught by another spacecraft.

 

[Asbo Zaprudder]

Yeah, there's always gravitational assist, including from Jupiter itself, and the so-called interplanetary transport network of Lagrange points -- if you're not in a hurry to get the samples back. If you have sufficient fuel, it's also worth exploiting the Oberth effect if possible during gravitational assist to maximise the kinetic energy gain.

 

[publiusr]

Jupiter, the Atlanta/Hartsfield of the Sol system

 

[scotpens]

These are matters of style manual preferences and convention, and hardly universal law. The singular-or-plural convention for a group entity is especially arbitrary.

It's mainly a matter of U.S. vs. British usage. An American would say, "Ford has announced a new model." A Brit would say, "Ford have announced a new model."

 

[publiusr]

More on the clipper'
https://www.centauri-dreams.org/2020/11/17/a-new-source-for-plumes-on-europa/

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Interview
https://www.coasttocoastam.com/show/2021-01-24-show/

New book
https://thespacereview.com/article/4118/1
https://www.amazon.com/gp/product/0...d17aa7eb94a7f91498793f80a6d1dd&language=en_US

SLS
https://www.nasa.gov/exploration/systems/sls/multimedia/gallery/SLS_Concepts.html

 

[Captain pl1ngpl0ng]

https://europa.nasa.gov/

 

[publiusr]

More news:
https://www.centauri-dreams.org/2021/07/14/europa-below-the-impact-zone/

New tech
https://techxplore.com/news/2022-10-exploring-europa-silicon-germanium-transistor-technology.html

The next ride?
https://www.science.org/content/article/space-scientists-ready-starship-biggest-rocket-ever

 

[publiusr]

Europa Clipper bus mostly built…fitting out to come
https://www.centauri-dreams.org/2022/06/10/europa-catching-up-with-the-clipper/

Antenna tests
https://www.nextbigfuture.com/2022/10/nasa-europa-clipper-high-gain-antenna-tested.html

Juno's glimpse
https://behindtheblack.com/behind-t...-the-first-close-fly-by-of-europa-in-decades/

Cryobots
https://www.centauri-dreams.org/2022/07/01/drilling-into-icy-moon-oceans/
https://phys.org/news/2022-07-nasa-robots-habitable-ocean-worlds.html

A humanoid diver-bot
https://techxplore.com/news/2022-07-underwater-robot-humans-sight-deep.html

What a cryobot might see
https://www.universetoday.com/15732...rer-might-see-when-it-reaches-europas-oceans/

JUNO’s orbit
https://www.centauri-dreams.org/2022/09/26/juno-closes-on-europa/

Europa's evolution
https://phys.org/news/2023-06-jupiter-moon-europa-evolution.html