NASA - Europa Clipper updates and discussion

[DanClemmensen]

The fact that I'm slightly concerned about specific LV config flight history does not imply that I think it should have gone onto another vehicle.

The only plausible alternate launcher is the Delta IV Heavy with a kick stage, IMO. However it is pricey and somewhat lacking in performance when compared to the Falcon Heavy.

The single remaining Delta IV heavy is scheduled to launch NROL-70 on 14 March 2024. ULA announced that this was the last one before retirement, and as I understand it ULA can no longer produce any more.

On the other hand, Congress originally mandated that Europa Clipper was to be launched on SLS. What could possibly be wrong with that?

[Zed_Noir]

The fact that I'm slightly concerned about specific LV config flight history does not imply that I think it should have gone onto another vehicle.

The only plausible alternate launcher is the Delta IV Heavy with a kick stage, IMO. However it is pricey and somewhat lacking in performance when compared to the Falcon Heavy.

The single remaining Delta IV heavy is scheduled to launch NROL-70 on 14 March 2024. ULA announced that this was the last one before retirement, and as I understand it ULA can no longer produce any more.
<snip>

Presuming NASA ordered a Delta IV Heavy before ULA announced it's retirement. However AIUI a political side deal was struck for support of the Europa Clipper for it launching on the SLS make the Delta IV Heavy option not very viable until it was too late to ordered one.

[redliox]

OK, we are apparently trying to identify what is most likely to degrade or kill the mission. You are focusing on a potential problem associated with this particular FH configuration, and of  course you may be correct. I would be more concerned about solar array and antenna deployment problems, given recent BLEO experiences. With no inside information, my concern has no particular validity. FH has launched 9 times. Its configurations are quite similar to each other. Europa Clipper has never launched before, so it's actual characteristics have not been validated in space.

One topic I'd be curious on: how does the (expected) radiation exposure for 'Clipper compare against Juno?  Juno, largely because of its orbit, has held up remarkably well against Jupiter and even throwing in bonus flybys of Io which was probably the last thing it was designed to handle.    Juno's been threading the eye of the hurricane whereas 'Clipper will have to pass through the storm, for a crude analogy.  Will 'Clipper have half the luck Juno had in avoiding radiation damage in all its horrors?

[ugordan]

The only plausible alternate launcher is the Delta IV Heavy with a kick stage, IMO. However it is pricey and somewhat lacking in performance when compared to the Falcon Heavy.

Not enough performance that's needed for the Clipper's injection C3 energy IIRC. Kick stages are fine for lighter spacecraft like New Horizons, Parker Solar Probe, where the lower Isp of the solid prop can offset the dry mass of the upper stage, not so much for a 6 tonne behemoth that is the Europa Clipper.

No, SLS not withstanding, FH is the only operational western vehicle right now that can brute-force its was to the design trajctory. But we've been over all this many, many times before already so it's a moot discussion.

[deadman1204]

OK, we are apparently trying to identify what is most likely to degrade or kill the mission. You are focusing on a potential problem associated with this particular FH configuration, and of  course you may be correct. I would be more concerned about solar array and antenna deployment problems, given recent BLEO experiences. With no inside information, my concern has no particular validity. FH has launched 9 times. Its configurations are quite similar to each other. Europa Clipper has never launched before, so it's actual characteristics have not been validated in space.

One topic I'd be curious on: how does the (expected) radiation exposure for 'Clipper compare against Juno?  Juno, largely because of its orbit, has held up remarkably well against Jupiter and even throwing in bonus flybys of Io which was probably the last thing it was designed to handle.    Juno's been threading the eye of the hurricane whereas 'Clipper will have to pass through the storm, for a crude analogy.  Will 'Clipper have half the luck Juno had in avoiding radiation damage in all its horrors?

I thought Clipper was also gonna use an eliptical orbit. So going in and out of the radiation belt. Though this time, intentionally 

[FutureSpaceTourist]

https://flic.kr/p/2pB37G3

KSC-20240227-PH-LNL01_0007
Technicians hoist a five-panel solar array protected by a lid for NASA’s Europa Clipper spacecraft at the Payload Hazardous Servicing Facility at the agency’s Kennedy Space Center in Florida on Tuesday, Feb. 27, 2024. The arrays are each 46.5 feet long (14.2 meters). With both solar arrays deployed, Europa Clipper will span more than 100 feet long, about the length of a basketball court. The solar arrays power the spacecraft so it can study Jupiter’s icy moon, Europa, which is more than five times as far from the Sun as the Earth. Launch on a SpaceX Falcon Heavy rocket is no earlier than October 2024. Photo credit: NASA/Leejay Lockhart

https://flic.kr/p/2pB4nJ2

KSC-20240227-PH-LNL01_0004
Technicians hoist a five-panel solar array protected by a lid for NASA’s Europa Clipper spacecraft at the Payload Hazardous Servicing Facility at the agency’s Kennedy Space Center in Florida on Tuesday, Feb. 27, 2024. The arrays are each 46.5 feet long (14.2 meters). With both solar arrays deployed, Europa Clipper will span more than 100 feet long, about the length of a basketball court. The solar arrays power the spacecraft so it can study Jupiter’s icy moon, Europa, which is more than five times as far from the Sun as the Earth. Launch on a SpaceX Falcon Heavy rocket is no earlier than October 2024. Photo credit: NASA/Leejay Lockhart

[FossilDS]

One topic I'd be curious on: how does the (expected) radiation exposure for 'Clipper compare against Juno?  Juno, largely because of its orbit, has held up remarkably well against Jupiter and even throwing in bonus flybys of Io which was probably the last thing it was designed to handle.    Juno's been threading the eye of the hurricane whereas 'Clipper will have to pass through the storm, for a crude analogy.  Will 'Clipper have half the luck Juno had in avoiding radiation damage in all its horrors?

(Extremely) late reply, but according to this paper detailing Clipper's trajectory design, the total ionizing dose should be no more then  2.8 megarads (Mrads):  https://www.trylam.com/CPP/AIAA_SPACE2014_Buffington_PrePrint_v2.pdf

Note that this paper was made with SLS in mind, so the dates are bit off but the tour is still basically the same. For comparison, Galileo was estimated to have accrued 600 kilorads (0.6 Mrads) of radiation over it's tour (not 100% sure about this though), and Juno a whopping 11 Mrads. Nevertheless, despite Juno's titanic radiation dose, it is still about 5 times less then if it were inserted into an equatorial orbit, and due to it's thick radiation vault Juno's electronics needs to tolerate "only" about 25 Krads (still a fatal dose for most complex lifeforms, but much better then 11 Mrads). It is testament to how robust Juno's radiation shielding is that the spacecraft is still in good working order while Galileo struggled with a much smaller radiation dose.

Nevertheless, in Europa Clipper's case, as you can see in the attached diagram, the majority of the spacecraft's time is spent in a relatively benign area outside of the Jovian radiation belts. This was a key design consideration and one of the reasons why a Europa orbiter was not pursued- a Europa Orbiter would have had a 4 Mrad radiation dosage for about only a few months in Europan orbit, while Europa Clippers' 3 Mrads will span over several years of operation.

[redliox]

How do the rad vaults of Juno and 'Clipper compare?  It sounded like Juno's vault handled over twice what the latter will endure and did it with flying colors.

[matthewkantar]

Juno’s vault is 10 mm thick titanium, Europa Clipper’s is 9.2 mm aluminum-zinc alloy.

[vjkane]

I believe that’s a 2014 paper.

[FossilDS]

I believe that’s a 2014 paper.

True, but I don't think Clipper's overall tour has changed very much from 2014 to 2023, apart from entering Jupiter orbit later, so the radiation dosage should be similar. In fact, in this 2023 article, https://www.space.com/europa-clipper-mission-explained, a person on the Clipper team says that they "expect to receive about 3 megarads (Mrad)", so it's still a decently accurate idea of Clipper's total radiation dosage. 

[redliox]

Juno’s vault is 10 mm thick titanium, Europa Clipper’s is 9.2 mm aluminum-zinc alloy.

Do those differ much in shielding terms?  Everyone knows about lead, but of course it's too heavy for spaceflight.

[matthewkantar]

Juno’s vault is 10 mm thick titanium, Europa Clipper’s is 9.2 mm aluminum-zinc alloy.

Do those differ much in shielding terms?  Everyone knows about lead, but of course it's too heavy for spaceflight.

I read in one of the NASA pages I found the material and thickness info in that lead is also too weak to hold up to launch conditions.

[matthewkantar]

Juno’s vault is 10 mm thick titanium, Europa Clipper’s is 9.2 mm aluminum-zinc alloy.

Do those differ much in shielding terms?  Everyone knows about lead, but of course it's too heavy for spaceflight.

I read in one of the NASA pages I found the material and thickness info in that lead is also too weak to hold up to launch conditions.

[ugordan]

Juno’s vault is 10 mm thick titanium, Europa Clipper’s is 9.2 mm aluminum-zinc alloy.

Do those differ much in shielding terms?  Everyone knows about lead, but of course it's too heavy for spaceflight.

Lead may not be the optimal material for the radiation environment encountered in Jupiter's radiation belts, anyway.

I might be way out of my league here, but I'd assume the bulk of Jupiter's radiation belt dosage comes from high energy trapped electrons, with a lower percentage of protons and other heavier nuclei (supplied primarily from Io, like sodium, sulfur, etc.). You don't need lead to stop electrons, although the resulting braking of the particles will induce x-ray Bremsstrahlung for which lead would still probably be a better candidate at stopping. It's always a tradeoff.

[Targeteer]

https://blogs.nasa.gov/europaclipper/

Author Jamie GrohPosted on March 12, 2024
   
Three people in jumpsuits stand in front of a stretched out five-panel solar array inside of a building.
Technicians examine the first of two fully extended five-panel solar arrays built for NASA’s Europa Clipper suspended on a support system called a gravity offload fixture during inspection and cleaning as part of assembly, test, and launch operations inside the Payload Hazardous Servicing Facility at the agency’s Kennedy Space Center in Florida on Wednesday, March 6, 2024. Photo credit:
NASA/Ben Smegelsky

Processing of the large solar arrays built for NASA’s Europa Clipper is now underway inside the Payload Hazardous Servicing Facility at the agency’s Kennedy Space Center in Florida.

Planned to arrive at Jupiter in April 2030, the spacecraft will study Jupiter’s moon Europa, which shows strong evidence beneath its icy crust of a global ocean over twice the volume of all Earth’s oceans. Europa is currently considered one of the most promising habitable environments in our solar system.

The first of two five-panel solar arrays built for NASA’s Europa Clipper stands inside the Payload Hazardous Servicing Facility at the agency’s Kennedy Space Center in Florida in preparation for inspection and cleaning as part of assembly, test, and launch operations on Wednesday, March 6, 2024. Photo credit: NASA/Ben Smegelsky

Once processing of the first five-panel solar array is complete, technicians will remove it from the gravity offload fixture, which helps support the weight of the array. The same steps will then be repeated with the second solar array. Built by Airbus in Leiden, Netherlands, the arrays arrived at Kennedy late last month by truck, after travelling to the U.S. by air.

When both solar arrays are installed and deployed on Europa Clipper – the agency’s largest spacecraft ever developed for a planetary mission – the spacecraft will span a total length of more than 100 feet and weigh 7,145 pounds without the inclusion of propellants. The spacecraft needs the large solar arrays to collect enough light to power it as it operates in the Jupiter system, which is more than five times as far from the Sun as Earth.

Europa Clipper is being assembled at NASA’s Jet Propulsion Laboratory in Southern California and is managed in partnership with Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland. The spacecraft will ship to Florida later this year for launch aboard a SpaceX Falcon Heavy rocket from Kennedy’s Launch Complex 39A. NASA’s Launch Services Program, based at Kennedy, is managing the launch service. 


   

[FutureSpaceTourist]

https://flic.kr/p/2pCWe3J

https://flic.kr/p/2pD3YcL

[StraumliBlight]

Spacecraft assembly, test, and launch operations mechanical engineer Steve Barajas and science systems engineer Jenny Kampmeier provide a behind-the-scenes look at the nearly completed spacecraft in the High Bay 1 clean room at JPL.

Also live stream from Clean Room:

[Star One]

Exploring the icy moons of Saturn and Jupiter has long been a focal point for scientists in the quest for extraterrestrial life. According to new research, even microscopic amounts of cellular material ejected from moons or exoplanets could reveal signs of life to the instruments on missions slated for the near future.

This fascinating study, conducted by researchers from the University of Washington in Seattle and Freie Universität Berlin, offers promising insights for these upcoming exploration missions.

…

The Europa Clipper’s SUrface Dust Analyzer represents a leap forward in space exploration instruments, capable of detecting negatively charged ions and better suited for identifying fatty acids and lipids. Klenner finds the prospect of searching for lipids more exciting than searching for DNA’s building blocks due to their stability.

Senior author Frank Postberg from Freie Universität Berlin concludes, “With suitable instrumentation, such as the SUrface Dust Analyzer on NASA’s Europa Clipper space probe, it might be easier than we thought to find life, or traces of it, on icy moons.”

This optimistic outlook hinges on the presence of life and its incorporation into ice grains from subsurface water reservoirs, paving the way for exciting discoveries in the search for extraterrestrial life.

https://www.earth.com/news/extraterrestrial-life-moons-planets-detected-single-grain-ice-floating/

Related paper:

https://www.science.org/doi/10.1126/sciadv.adl0849

[FutureSpaceTourist]