ESA – Jupiter Icy Moons Explorer: Live Launch

Hah yes, I think it evokes the feel of Peter Watts but also qntm / Sam Hughes even more!

Mostly in the constant "what the ___ am I reading/watching/thinking right now"

The last update on 20021 was from April 2021 when Jon announced it was delayed (with no specific information on when it would be ready): https://www.reddit.com/r/Jon_Bois/comments/mwmo0i/programmin...

I think it's on purpose.

It didn't crash for me and after I revisited the site, it shows a different page which allows to select the chapter.

I like this theory better than mine. My jaded view of bureaucracy has me thinking that there are additional fees for delaying the launch 24 hours or more.

Off the top of my head I'd have to say the planetary ephemerides are more of a factor than the earth's rotation. That much we have pretty down pat, otherwise they'd just announce it's at (Day+23.6h)

Well, sure, the window was very specific to visit multiple planets, but Jupiter was the first stop. Similar Earth-Jupiter configuration happens every year.

Indeed. The same rocket will give a light probe a much higher velocity than a large probe. The launch vehicle for JUICE is the Ariane 5 ECA which can launch 16 tonnes to low earth orbit[1], while the Titan IIIE that launched the Voyagers had a capability of 15.4 tonnes to a (lower) low earth orbit[2]. So the current launch vehicle is a bit more powerful, but not 8 times as much. There are some more powerful (and more expensive) rockets active at the time, but nothing 8 times as powerful as the Titan IIIE.

So NASA has the choice of 1) launching a lighter/smaller probe with less scientific capabilities and endurance, 2) spend $$$ and time developing a much more powerful launch vehicle, or 3) have a few years of patience waiting for JUICE to get to Jupiter on a slower trajectory.

Jupiter has already been visited by multiple probes so sending a small and not very capable probe would not gain us much scientifically. (But this option was taken with the New Horizons probe to Pluto some years ago.) (2) Wouldn't actually be faster and much much much more expensive (see how long the SLS rocket is taking to get done. But mr. Musk is taking this route too with SpaceX's Starship, so this will be an option in the future if all goes well). So that leaves option 3, which NASA has taken. They could probably have opted for an existing more powerful and expensive launcher to shave some years off the transit, but they preferred to wait a bit longer and not spend that money.

[1]: http://www.astronautix.com/a/ariane5eca.html [2]: http://www.astronautix.com/t/titaniiie.html

That didn't affect the Earth-Jupiter leg, which was direct.

Here's a key figure [3]:

- "The mass injected into the Earth escape trajectory would be 4800 kg (without launch adapter), with a hyperbolic escape velocity of 3.15 km/s, which increases to 9.5 km/s after the last Earth swing-by"

The Voyagers were launched directly to hyperbolic excess of >10 km/s — comparable to the speed JUICE will reach on its third flyby, of Earth, in 2029.

https://sci-hub.ru/10.1016/j.actaastro.2019.06.013 ("C₃ of... 105.5 km²/s² and 102.4 km²/s² for Voyagers 1 and 2, respectively [75]")

I believe orbits are chaotic over a timespan of many millions of years (due to weak interactions with multiple other bodies), but accurately predictable over a human lifespan.

Indeed, the length of this antenna required some creativity. We have some really cool, high-tech solutions [1] for these "1-G challenges" as well.

[1] https://carbospacetech.com/innovations/zero-g-robot/

Yes, that's the role I'm looking to fill at the moment, but it's a small company, and the horizontal coupling is tight. A SWE here will be confronted with many hands-on EE and ME challenges as well (hence the on-site requirement). People who thrive in such environments are a good fit.

"I'm sorry, I didn't understand that. Here are some shopping results for furniture and sexual performance enhancer pills."

> Surprised they went with this decision.

ESA explains it like this [1]:

> Category II missions are flyby or orbiter missions that venture to worlds where there may be some possibility of life, but the chances of contamination are slim. Then there's category III, where the chances of contamination are deemed greater.

> The planetary protection classification for Ganymede is driven by the likelihood that living organisms from Earth, brought to Ganymede by the spacecraft, can make their way down to the ice-ocean interface [...] In turn, this likelihood is deemed so low for Ganymede that it justifies a category II protection level, allowing for the spacecraft to be disposed on Ganymede's surface.

[1] https://www.space.com/europe-juice-jupiter-mission-planetary...

If tardigrades can survive launch, deep space, Jovian orbital conditions for years, and a crash on Ganymede, and then be able to reproduce, maybe they deserve to be there.

That is a bizarre decision. Have we learned nothing from the hundreds or thousands of examples of humans inadvertently messing with ecosystems by introducing new organisms?

What, are you saying that it is expected that the probe will actually be inadvertently carrying Tardigrades that might actually survive to the surface? Hidden in little corners of the probe? Why didn't we sterilize it?

Why would there be a bunch of tardigrades sitting on the probe? Unless they walk out to their nearest moss pile and smear it all over I think the chances are remarkably, incredibly slim.

You know they go to every length to sterilize the probe before launch?

You could argue that the last two sentences were removed in the book version, since the book and film were written simultaneously and the book came out later.