JUICE, ESA's L-class mission to the Jovian system Options

[djellison]

that four out of four number is eyebrow-raising.

Why?

There isn't a spacecraft out there that hasn't had a failure with workarounds. These things are incomprehensibly complicated. Thousands of components.

Cassini had a reaction wheel go out super early. SOHO was nearly lost 20 years ago. Galileo's HGA. MGS's solar panels. MEX concerns over MARSIS deployment, MRO Ka band going down etc...etc...etc.

They all have their problems. And their teams work around it.

[StargazeInWonder]

I think you may have read a criticism in my comment that I didn't intend. Of course very complicated projects have problems that are often possible to overcome.

In this case, the similarity of the problems and the same target simply seemed curious. Lots of missions have lots of different issues, but here three had issues with something external failing to extend correctly, and all with the same target. It's certainly not pejorative regarding the teams, and as the problems with Galileo, Lucy, and JUICE all occurred so long before arrival at Jupiter, there's no casual relationship there.

It's also four different teams, two agencies, different decades… obviously no one pointing the blame at anyone.

[djellison]

It just seemed an odd comment to make - it appeared you were trying to infer there was something about the target that had something to do with the issues.

[StargazeInWonder]

Understood. No, the fact that these have happened so far from Jupiter makes that definitely coincidental. If they'd all happened in Jupiter's radiation belts, that'd be another thing.

Likewise, the Soviets had rotten luck with Mars missions, but some of them occurred at/near launch. Mars didn't cause that, but the mishaps randomly piled up that way. So it goes.

[tanjent]

Jupiter is the most distant target planet for which probes can manage on solar power without RTG's. So spacecraft going there need big panels, intricately folded prior to launch. Likewise I am guessing that the communications antennae need to be larger relative to the spacecraft itself than for probes heading to the inner planets and Mars. So the engineering challenges involved in powering and communicating with Jupiter-bound payloads are bound to be daunting.

[HSchirmer]

Jupiter is the most distant target planet for which probes can manage on solar power without RTG's. So spacecraft going there need big panels, intricately folded prior to launch. Likewise I am guessing that the communications antennae need to be larger relative to the spacecraft itself than for probes heading to the inner planets and Mars. So the engineering challenges involved in powering and communicating with Jupiter-bound payloads are bound to be daunting.

And it certainly doesn't help that, for a Jupiter-bound mission, you're on a heavy lift rocket.
So your delicate science probe that's assembled in a clean room and likely barely be able to support its own weight in earth gravity-
will spend several minutes being shaken within an inch of its life (specifications?) and blasted by 150+ decibels of sound energy.

As well as go from 1 atmosphere to hard vacuum in a matter of minutes and then from ~85° Fahrenheit to a rotisserie of +250°F and -150°F.

[vjkane]

Jupiter is the most distant target planet for which probes can manage on solar power without RTG's. So spacecraft going there need big panels, intricately folded prior to launch. Likewise I am guessing that the communications antennae need to be larger relative to the spacecraft itself than for probes heading to the inner planets and Mars. So the engineering challenges involved in powering and communicating with Jupiter-bound payloads are bound to be daunting.

There have been several proposed solar powered Discovery and New Frontiers-class missions for the Saturnian system across 2-3 competitions. I've never heard that the reasons they weren't chosen was because of the proposed use of solar power. Two of the losing teams gave debriefs on the reviews of their proposals at an OPAG meeting, and solar power wasn't mentioned.

Given how small this community is, if solar power wasn't going to get past reviewers (and the reviews assess technical feasibility), I think that would be known by now in the community. The recent Decadal Survey Enceladus multiflyby concept used RTG, and they note was that RTGs were more mass efficient.

I don't think that we can say for certain about solar power at Saturn until a mission is selected, but there are good examples of professionals in the field believing they can will mission concepts using solar power.

BTW, NASA is offering up to two MMRTGs for the upcoming NF5 competition. Missions have been proposed to each of the candidate destinations using solar power. If the winning mission does use solar power, the fuel could be repackaged into a next get RTG and offered to a Uranus mission. (Repackage for more efficient and long lived thermocouples than MMRTGs.) This would give the mission about a third of what's been desired in most Uranus flagship orbiter concept designs, or about enough for a NF-class orbiter. The alternative, per the recent OPAG meeting is to miss the early 2030s window and wait until the mid or late 2030s and much long flight times.


Space News: Plutonium availability constrains plans for future planetary missions

[stevesliva]

If we're talking Jupiter orbiter coincidences, I'd like to request a Shoemaker-Levy comet impact. TIA!

[MahFL]

Trying to be neutral on the subject, you'd think by now mechanical engineering could design some 99.999% reliable release mechanisms...

[djellison]

What does it tell you about the scope and scale of the design problems and the challenges these unique environments present that - across different agencies, different contractors and both public and private sector projects.........problems of this kind emerge from time to time.

Fascinating reading here - https://ntrs.nasa.gov/api/citations/2021002...nal%20Paper.pdf

[HSchirmer]

What does it tell you about the scope and scale of the design problems and the challenges these unique environments present that - across different agencies, different contractors and both public and private sector projects.........problems of this kind emerge from time to time.

Fascinating reading here - https://ntrs.nasa.gov/api/citations/2021002...nal%20Paper.pdf

Along similar lines some fascinating viewing- YouTube engineering discussion of a cleanroom tour for Hubble

https://youtu.be/Pu97IiO_yDI

[Quetzalcoatl]

Bonsoir,

Deployment of Juice instruments completed. Details of operations.

https://www.esa.int/Science_Exploration/Spa...orm_for_Jupiter

[bobik]

PEP-Hi (JENI and JoEE) commissioning was reportedly successfully completed on 14 June. PEP-Lo (JDC, JEI, JNA, NIM) commissioning is planned to be completed on 30 June.

It's a pity that such and other information are hidden on various social media websites and not centrally collected in an ESA blog or something.

[john_s]

Nice story on the RIME deployment anomaly here

[nprev]

A superb story of ingenuity and success indeed. Thanks for posting the link, John!