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ESA’s Juice lifts off on quest to discover secrets of Jupiter’s icy moons

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Re: ESA’s Juice lifts off on quest to discover secrets of Jupiter’s icy moons

#41

Post by midasuni »

dmix wrote: post #36
krylon wrote: post #32

Earlier quoted context omitted.

IIRC, the USSR had really bad luck with the various probes they sent to Mars. A couple crashed, and I think one or two got off course and were lost.

Idk about Mars but that was definitely the experience on Venus (which was far more understandable since they were sending metal balls that would be crushed under pressure within minutes). Only survived about 2-3/10.

Feels like Mars eats most probes. Mars96 and Mars polar observer come to kind immediately. I believe my name was on a cd on one of them as an early internet thing you could do. Never made it to mars.

Re: ESA’s Juice lifts off on quest to discover secrets of Jupiter’s icy moons

#42

Post by mdorazio »

TaylorAlexander wrote: post #29
drewg123 wrote: post #6

Wow, 11 years to Jupiter. I wish we had better propulsion systems. EDIT: This wasn't meant to disrespect the ESA mission. I'm just sad that the outer planets are years away, rather than the hours, days, weeks or months of science fiction.

I think the very big rocket planned for launch in a few days will, if successful, help a lot with this. Chemical rockets aren't the best but if we can launch much larger payloads, we can design deep space rockets that consume a lot more fuel to get there faster. Imagine a multi stage rocket which is assembled in orbit from multiple Starship launches, and then blasts off to the outer worlds.

I don't think you would need to assemble anything in space. Starship's planned LEO payload is about a third of the entire mass of the Ariane 5 rocket that launched Juice. If you have that kind of mass budget at orbit, your delta v capability is pretty massive for a space probe.

Re: ESA’s Juice lifts off on quest to discover secrets of Jupiter’s icy moons

#43

Post by kumarvvr »

With the likes of SpaceX being around, is it not possible to have a store of fuel in orbit, so that these missions can pick a tank or two of them, slingshot their way and use the fuel to speed up the journey?

Or, is it purely economics at play?

Re: ESA’s Juice lifts off on quest to discover secrets of Jupiter’s icy moons

#44

Post by jimmygrapes »

drewg123 wrote: post #12
huhtenberg wrote: post #9

Earlier quoted context omitted.

8 years, not 11. > Arrival at Jupiter - July 2031 https://www.esa.int/var/esa/storage/images/esa_multimedia/im...

I stand corrected. I erroneously picked up 2034 from the timeline. But the point still stands; 8 years is a depressingly long time. If we base missions on the discoveries of previous missions, there is an 8-year minimum gap between missions. I'm just hoping we find evidence of extraterrestrial life in my lifetime, and at this rate, we'll be cutting it close..

8 years ago we were pretty much where we are now. It will come faster than you might thinkm

Re: ESA’s Juice lifts off on quest to discover secrets of Jupiter’s icy moons

#45

Post by DiggyJohnson »

beebeepka wrote: post #22
twic wrote: post #19

Earlier quoted context omitted.

What? How does getting there more slowly mean more science at the destination? And if so, why is Europa Clipper going to get there much faster?

Maybe slower speed means more time spent in close proximity. Moving things don't exactly stop on their own in space. Or maybe they wanted more stuff on there

It’s the latter.

Re: ESA’s Juice lifts off on quest to discover secrets of Jupiter’s icy moons

#46

Post by dmix »

midasuni wrote: post #41
dmix wrote: post #36

Earlier quoted context omitted.

Idk about Mars but that was definitely the experience on Venus (which was far more understandable since they were sending metal balls that would be crushed under pressure within minutes). Only survived about 2-3/10.

Feels like Mars eats most probes. Mars96 and Mars polar observer come to kind immediately. I believe my name was on a cd on one of them as an early internet thing you could do. Never made it to mars.

At least your name is floating on a disc in space that's still pretty cool.

Re: ESA’s Juice lifts off on quest to discover secrets of Jupiter’s icy moons

#48

Post by ggm »

Would more energy be available for capture from Jupiter's reflectance or direct from the sun? My heart wants to say yes but my head thinks even as a point source, direct solar energy is higher.

If it was other RF or heat, maybe not. I wonder if a Stirling engine could work alternating shade and Jupiter's direct radiation?

I also wondered if lowering a long tail could acquire electrostatic energy greater than its coefficient of drag. As above, cute but .. no.

The proof by example answer is "if it had been viable they'd have done it"

Re: ESA’s Juice lifts off on quest to discover secrets of Jupiter’s icy moons

#49

Post by magicalhippo »

twic wrote: post #19
eep_social wrote: post #17

Earlier quoted context omitted.

This was an intentional choice for efficiency and to allow more science at the destination, “the final flyby.. will be 3700 km from Earth in November 2026” [1] Really disappointing that this is top comment tbh. [1] https://sci.esa.int/web/juice/-/58815-juices-journey-to-jupi...

What? How does getting there more slowly mean more science at the destination? And if so, why is Europa Clipper going to get there much faster?

Depends on what "more science" means, but one factor is that going fast means you need to burn a lot more fuel to slow down so you can get into orbit around the target planet.

The mass of the fuel spent on breaking could be spent on other things, like extra instruments, or fuel for thrusters so you can orient more often and stay in orbit longer. For example, the Galileo[1], Cassini[2] and Dawn[3] missions ended primarily due to the probes running out of fuel. Perhaps not the best examples since they all had quite long runs, but still, more thruster fuel would probably have meant even longer missions.

[1]: https://solarsystem.nasa.gov/missions/galileo/timeline/#jour...

[2]: https://solarsystem.nasa.gov/missions/cassini/mission/grand-...

[3]: https://www.jpl.nasa.gov/news/nasas-dawn-mission-to-asteroid...

Re: ESA’s Juice lifts off on quest to discover secrets of Jupiter’s icy moons

#50

Post by perihelions »

overthrow wrote: post #30
sfifs wrote: post #27

Earlier quoted context omitted.

What is actually the obvious reason to ban nuclear detonation in space (Not planetside) other than proliferation & security concerns?

Your question got me curious so I did some googling. The current international agreement is (best I can tell) UNITED NATlONS: GENERAL ASSEMBLY RESOLUTION AND PRINCIPLES RELEVANT TO THE USE OF NUCLEAR POWER SOURCES IN OUTER SPACE [December 14, 1992] https://csps.aerospace.org/sites/default/files/2021-08/Princ... I only skimmed, but it says this: > In order to mlnlmlze the quantity of radioactLve materzal in space and…

That's a non-binding UN resolution. There's treaties about nuclear weapons in space that have the force of law (ratified by US & USSR), but there's nothing for nuclear reactors AFAIK.
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