Europa Clipper Development, Build And Prelaunch Activities Options

[nprev]

The spacecraft has entered its preliminary design review phase, so I think it's time to begin discussion of what promises to be a fascinating journey to one of the most interesting destinations in the Solar System. Dr. Robert Pappalardo, the mission's chief scientist, delivered an overview of Europa as well as a top-level description of instrumentation and objectives during a talk tonight at the Griffith Observatory as part of their monthly "All Space Considered" series, so that serves as a good starting point. His presentation starts at 29:35.

As a reminder, please carefully review rule 1.3 before commenting. In fact, please review all of them. Thanks!


Europa Clipper Presentation (29:35)

[vjkane]

Dr. Robert Pappalardo, the mission's chief scientist, delivered an overview of Europa as well as a top-level description of instrumentation and objectives during a talk tonight at the Griffith Observatory as part of their monthly "All Space Considered" series, so that serves as a good starting point. His presentation starts at 29:35.

Europa Clipper Presentation (29:35)

I listened to the talk given yesterday by Bob Pappalardo, project scientist for the Clipper mission, at the Griffith Observatory. In general, the talk was aimed at the general public and did not go into many details. There were some tidbits that were new to me:

He stated that the project is keeping the spacecraft compatible with launch by the Delta IV Heavy, Falcon Heavy, and SLS. The former two would result in cruises of nearly 8 years, the latter 2 years.

He stated that the mission will do a number of Callisto and Ganymede flybys when they flip the orbit to go from flybys on the anti-Jovian hemisphere to the pro-Jovian hemisphere. (I've also read that there will be several flybys of these moons early in the mission as they crank down the orbit for to shorten the period and lower the periapsis to Europa's orbit.)

He also stated that the likely limiting factor for the mission would be the decay of power from the solar cells as they are degraded by the radiation. (Which brings up the idea to me that at some point they could raise the periapsis of the orbit out of the intense radiation field and become a Jovian system observatory for some period. ESA's JUICE mission will orbit Ganymede and do a number of Callisto flybys. Don't know the science return for additional flybys of these moons by the Clipper spacecraft late in its mission.)

The current disposal plan is to dump the spacecraft into Jupiter, although crashing the craft onto Ganymede or Callisto remains a possibility. (From a previous public lecture, another Clipper manager said his favorite idea was to crash into Io, collecting data on the way in. Don't know if that remains a feasible option.)

[nprev]

One thing that really caught my notice is that they're expecting 0.5m resolution of Europa at selected times/passes. He used the phrase "HiRISE-quality". Was rather surprised by that; I'm assuming that means that at least some of the flyby relative velocities are fairly low.

Characterization of surface roughness at that scale will be enormously helpful for future lander mission planning, of course. I wonder if they'll be able to achieve something similar during the Ganymede & Callisto flybys?

[antipode]

Oh dear, according to the latest PEN newsletter, the ICEMAG Europa interior characterisation instrument has been terminated due to cost overruns.

P

[nprev]

Do you have a link to that, Antipode? Didn't find anything via a quick Google.

[antipode]

PLANETARY EXPLORATION NEWSLETTER
Volume 13, Number 10 (March 5, 2019)

PEN Website: http://planetarynews.org

P

[nprev]

Thank you.

Bad news indeed. However, it does seem that the mission will likely still include a magnetometer albeit a less complex (and capable) instrument, perhaps a flight spare of some sort from another project.

This is not without precedent; seems to happen more often than not for most missions, actually. Hopefully the legendary ingenuity of NASA will find a way forward.

[Explorer1]

Too bad; luckily, JUICE will definitely carry a magnetometer too (called J-MAG).

[MahFL]

PLANETARY EXPLORATION NEWSLETTER
Volume 13, Number 10 (March 5, 2019)

PEN Website: http://planetarynews.org

P

300% cost increase...

[Bjorn Jonsson]

I noticed that according to the PEN newsletter, a simpler, less complex magnetometer will be included on Europa Clipper if possible. Hopefully this is possible since including a magnetometer is really important for exploring Europa properly (the subsurface ocean in particular).

[JRehling]

Since JUICE and EC will run concurrently, it would be particularly nice to have them both operating at the same time, in the event that both of them might make a close Europa pass at the same time. A magnetic field inside another magnetic field is a complex beast, and getting measurements along two trajectories at once would be a bonus.

JUICE won't make that many passes by Europa, so it can't possibly replace the science value that a magnetometer on EC would offer.

I'm still smarting over the fact that Dawn had its magnetometer downscoped away.

[Guest_Steve5304_*]

This isn't Clipper. That's the Euro mission.


And it looks like the Russian's and Chinese may very well send their own vessel also. So possible 3 missions to Europa, Ganymede during the 2030's.

[JRehling]

The latest review of Europa Clipper and Europa Lander paints a less-than-rosy picture of the status of each.

https://www.sciencemag.org/news/2019/05/wit...a-s-back-burner

(This article is more about the Lander than the Clipper, so the match with this forum is ~40%.)

These sagas go back and forth as we all know, but it seems like postponement is a solid possibility for the Clipper and more than likely for the Lander.

[vjkane]

The latest review of Europa Clipper and Europa Lander paints a less-than-rosy picture of the status of each.

A friend of mine in the professional space community pointed out to me that these reports often document problems well known to the development teams. Often by the time the reports are published, project management is well toward solving the problem

[Jaro_in_Montreal]

Yaay !!

https://www.nasa.gov/feature/europa-clipper...-moon-confirmed

[Jaro_in_Montreal]

BTW, I remember reading a detailed Europa Clipper mission proposal somewhere, but now I can't find it in my files.
Anybody here remember where it was posted?
A quick Google search came up empty.
Thnx

[JRehling]

Maybe this is the one you were thinking of?

https://smd-prod.s3.amazonaws.com/science-r...S_Sept_2016.pdf

One thing that catches my eye is that virtually all of Europa would be mapped at better than 30m per pixel with a median of about 9m per pixel. Due to orbital mechanics that are easy to visualize (flybys just inside or outside of Europa's orbit), there is a rough 180° periodicity in the coverage with the sub-jovian and anti-jovian regions imaged with the best resolution and the leading and trailing regions imaged with the worst resolution. This is approximately 10 times higher resolution than Viking coverage of Mars.

[nprev]

Panel discussion tomorrow (23 Oct 19) about Clipper featuring Bob Pappalardo and TPS CEO Bill Nye, 1030 US Pacific Daylight Time, 1730 GMT. NASA TV link.

[Explorer1]

I didn't want to start a new topic in the book subforum, but I wanted to let everyone know about 'The Mission' by David Brown; a fantastic book about the long history of Europa missions that recently released and everything that led up to the Europa Clipper's development so far. I'm only in chapter 4 of the audio version, but it's filled with all sorts of details on JIMO and previous proposals, as well as the nitty-gritty scientists, bureaucrats, politicians, (as well as some some cameos by posters on this very forum)! I had never known the origin of OPAG and MEPAG, the various rivalries, and the constant competition for scarce dollars.
The author has done quite a bit of science writing on space missions, and the prose is a good mix of details that will interest both experts and amateurs. It really emphasizes the long slog before even the first physical part of a probe destined for space is machined. I think there will be plenty new even to the users of UMSF.

[mcaplinger]

I wanted to let everyone know about 'The Mission' by David Brown; a fantastic book about the long history of Europa missions...

Since I was on a number of teams for the 3 or 4 precursor missions and on a losing team for Clipper itself, I found that the book omitted all of the interesting details about those competitions (few of which, I expect, will ever be public). Not a surprise, since history is written by the winners...

[JRehling]

Richard Greenberg's books about the science of Europa are extremely lively, documenting some passionate disagreements, to put it mildly. I suspect that the rivalries in engineering a Europa mission are mainly about different issues, not necessarily scientific ones, but it seems like there has to be some aspect of the thin-ice vs thick-ice theories coming into play, at least during the ~2002-2014 era. But I am only on the outside looking in.

[scalbers]

Nice talk by Bob Pappalardo on Europa Clipper was presented on May 12, and can be watched on YouTube:

https://www.youtube.com/watch?v=8ZMZuiiaAmQ&t=4s

[volcanopele]

Europa Clipper now has a launch vehicle: a SpaceX Falcon Heavy. Launch is now set for October 2024.

https://www.nasa.gov/press-release/nasa-awa...clipper-mission

[stevesliva]

Europa Clipper now has a launch vehicle: a SpaceX Falcon Heavy.

The total contract award amount for launch services is approximately $178 million.

Should go back to launching in pairs for this price.

[djellison]

Should go back to launching in pairs for this price.

The rocket isn't the expensive part. For this mission it's less than 5% of the budget.

[Explorer1]

$178 million is pocket change compared with SLS anyway. Massive savings by any measures (I could say more about SLS, but the p-word would be involved)....

Having a launch vehicle finalized is a big milestone; will be an impressive sight!

[StargazeInWonder]

This description of the Europa Clipper radar instrument, REASON, has a date of 2015, but seems to remain valid:

https://www.lpi.usra.edu/opag/meetings/aug2.../8_f_REASON.pdf

There is good reason to believe that the icy shell will have a fair degree of global consistency for depth and structure, with local exceptions. The radar campaign of Europa Clipper will not map Europa's surface comprehensively, but rather provide a partial grid of widely-separated tracks, with good vertical resolution along those tracks. This should provide excellent coverage of the global parameters for the shell's structure, surface texture, and – if existing conceptions of the shell's
depth and REASON's performance hold – thickness. If exceptions to the global trends (eg, pockets of liquid water closer to the surface) are not very rare, then the grid of ground tracks will intersect them, sampling them occasionally. I guess if there's an extended mission, there would be high priority on additional ground tracks to target areas of suspected interest that were missed or grazed during the main mission. The coverage map in the linked paper shows that at least in many locations the coverage will be pretty dense. Amusingly, the ground tracks look quite similar in distribution to the linea features around longitude 225W and elsewhere, so hopefully we don't end up just missing something of interest if the ground tracks remain parallel to geological features for thousands of km, just missing them along the entire length.

[scalbers]

Live video stream of Europa Clipper assembly:

https://europa.nasa.gov/spacecraft/assembly/

https://www.youtube.com/watch?v=yk0X3Sh2gIE

[Steve G]

Europa Clipper will be arriving in Jupiter orbit in April 2030. It will take about a year to get it into the science orbit. I can't locate any schematics of the initial orbits, and potential flybys of Ganymede, Calisto, or distant observations of Io. Can anyone assist?

[mcaplinger]

https://ntrs.nasa.gov/citations/20160008162 is an old paper that describes an earlier tour design. I couldn't find anything more recent that wasn't paywalled.

At one point the claim was made that there would be no science observations made of the other satellites to save costs, but I doubt that will hold once they're flying.

[volcanopele]

I will note that the current tour SPICE kernel is on the NAIF kernel site. If you know how to use something like spiceypy, one could create a python script that gives you all the flybys.......

[StargazeInWonder]

Here is a map that aggregates all of the ground tracks, which displayed an impressively dense grid-like coverage of the entire surface, though with some concentrations reflecting the realities of orbital geometry.

https://www.hou.usra.edu/meetings/lpsc2023/pdf/1518.pdf

It notes, at a high level, that the early orbits will focus on the anti-Jupiter hemisphere and then the later orbits will focus on the sub-Jupiter hemisphere.

Other commentary is here.

https://www.nasaspaceflight.com/2024/04/ec-jpl-interview/

https://europa.nasa.gov/mission/timeline/

Because the main mission coverage is a bit uneven spatially, there's the prospect that features that seem intriguing given coverage from the main mission could be the targets of specific focus during any possible extended mission. This will introduce luck and chance as factors – will there be uniquely interesting features that just happen to be located near/far from the closest ground tracks, and how will the spacecraft hold up as radiation damage takes its toll? I think the subtext is that potential targets for any future landers will be of prime interest, and only time will tell if there are uniquely promising locations for a lander (as on Mars) or if there are, effectively, many areas that are more or less equally intriguing. We already know that there are isolated areas with more recent exposure to subsurface activity than is typical, but we don't have sufficient coverage from Galileo to characterize what might be the best locations.

The overlap with JUICE is important context, should both missions function perfectly. This would make EC's coverage of Ganymede and JUICE's coverage of Europa seemingly less important, but the instrument suites are not exactly identical, so perhaps those differences will be highlighted by circumstances where each observes the "other" moon. And it highlights the importance of the observations of Callisto, which is not the primary target of either mission, but will be visited a total of 21 times by these two orbiters, which would seem to offer the potential for excellent and definitive coverage (Galileo flew by Callisto only 3 times in the primary missions and 8 times in all). In fact, both EC and JUICE will each fly by Callisto more times than Galileo ever did.

[StargazeInWonder]

To the point, I think, of Steve's question, I took a look at the Galileo-era maps of the four Galileans and how coverage has varied, which is to say the least considerable. For each, portions have been mapped at scales of 1km/pixel or much better, while other large portions have been imaged at no better than 5km/pixel.

The successful completion of EC and JUICE will utterly supersede current imagery for Europa and Ganymede, and the contributions of each mission to "the other" moon in that pair will be essentially redundant, in terms of mapping. (I'm curious if the two different radar instruments will produce interestingly complimentary data in cases where the ground tracks cross.)

Neither will approach Io closely, but will potentially come as close to Io as Europa is to Io. That won't advance our global maps of Io except in the sense that Io's time-varying vulcanism makes even remote observations potentially interesting.

Callisto is the wildcard. As long as the flybys aren't completely undermined by redundant geometry, nightside closest approaches and/or policies against performing observations, those 21 combined flybys – nearly half as many as EC will make of Europa – should amount to the definitive exploration of Callisto. ESA is quite focused on their end of this; note that the mission name itself is not specific to Ganymede and Callisto is indeed a primary target of the mission, even if it's not as primary as Ganymede. Some interesting and fun discussion here:

https://www.esa.int/Enabling_Support/Operat...isto_flyby_test