Printable Version of Topic

Posted by: MikeH Mar 8 2020, 11:47 PM

News article in Nature about an upcoming launch window in the 2030s for Uranus and Neptune (no paywall):

https://www.nature.com/articles/d41586-020-00619-y

Posted by: James S. Mar 9 2020, 03:50 PM

This will be so AWESOME, if it does happen. Would be the icing on the cake after Pluto and New Horizons. I hope I'm alive to see this, as I just turned 53 this past January.

James

Posted by: titanicrivers Mar 13 2020, 05:07 PM

Not sure if the abstracts from this Royal Society scientific meeting on Future Exploration of the Ice Giants were referenced in other posts on Unmanned Spaceflight. If not here is the link: https://royalsociety.org/science-events-and-lectures/2020/01/ice-giants/

Posted by: stevesliva Mar 13 2020, 05:55 PM

The current 'Outer Planets' SNAFU is really tempering my enthusiasm here:
https://www.planetary.org/blogs/casey-dreier/2020/fy-2021-pbr-for-planetary-science.html

And I'll leave it at that for the longstanding pro-harmony reasons of this forum, but I just want the few readers here to be aware.

Posted by: vjkane Mar 14 2020, 04:19 AM

Both the John Hopkins Applied Physics Lab and JPL are working to define New Frontiers-class Uranus orbiters. The abstracts don't mention whether or not an atmospheric probe could be included. The key is the attempt to drastically reduce the orbiter cost.

http://www.hou.usra.edu/meetings/lpsc2020/pdf/1428.pdf

https://www.hou.usra.edu/meetings/lpsc2020/pdf/2277.pdf

Posted by: antipode Mar 19 2020, 01:06 AM

Has anyone proposed a flyby plus probe combination? Just asking.

P

Posted by: vjkane Mar 19 2020, 05:38 PM

Just flybys or flybys + atmospheric probes have been proposed a number of times. The consensus has been that the value of a flyby given its cost (generally assumed to be >$1B) isn't justified; better to wait for the funds for a much productive orbiter mission ($2-3B). Imagine how little we would have learned about the Saturn system if Cassini had been a flyby mission.

That said, the idea keeps coming up. By carefully subsetting the scientific goals, one could imagine a less expensive flyby mission that could be substantially cheaper. Trident, for example, made it to the Discovery finalist list by focusing its goals only on a single Trident flyby (although I'm sure there would be some ancillary Neptune observations).

Posted by: antipode Mar 21 2020, 05:43 AM

vjkane, I'm not suggesting its an ideal outcome, just one that might fall into the class of the good being the enemy of the perfect.
We might not get flagship class ice giant missions in any of our lifetimes. I expect some advance in ice giant science when the next generation of really big ground based telescopes come online,
but apart from that I was wondering what might be done with a New Horizons type package, with a magnetometer, with or without a probe.
Are there flight spares that could be used? Might this fit into a New Frontiers budget? And might there be opportunities for post ice giant flybys of TNOs?

P

Posted by: vjkane Mar 21 2020, 03:36 PM

I completely understand that reasoning. The planetary community also understands that if the Mars sample return goes forward, then affording a flagship Ice Giant mission will be difficult. JHU/APL and JPL are both working on mission concepts for New Frontiers-class Uranus orbiters. Here are links to two abstracts for the LPSC 2020 conference:

https://www.aidaily.co.uk/articles/microsoft-ai-mapping-the-future-of-our-forests
http://www.hou.usra.edu/meetings/lpsc2020/pdf/2277.pdf

While there's not a lot of detail in these, likely strategies would be to reduce the scope of science, fly fewer and simpler instruments than a flagship mission, and reduce data rates. The latter probably would be a key driver for lowering costs; data return is often the largest use of power on a mission (per one of Ralph Lorenz' papers). Reducing power ripples through the spacecraft design. I wouldn't be surprised if these concepts would have the spacecraft stay in long elliptical orbits so that there's plenty of time between close encounters to return data at a lower rate.

If an NF-class Uranus orbiter looks feasible, that would give the Decadal Survey more options to look at for ice giant missions.

I suspect that a Neptune NF-class orbiter isn't feasible. Longer flight time, further away so more power is needed to return the same amount of data, the craft has to fly fast to get to Neptune in a reasonable time so decelerating to enter orbiter may require something like aerocapture.

A couple of years ago, a portion of the outer planet community was recommending a combination of a Neptune flagship mission combined with a Uranus flyby+atmospheric probe that could continue to a KBO flyby.

In looking at reduced cost ice giant missions, one question always is, is there enough science returned to make this lower cost mission a better choice than spending the same money on a mission to a nearer target?

Posted by: Explorer1 Mar 21 2020, 11:15 PM

Neptune and Triton are so tempting (the geysers alone would be such a treat), but if we have to choose just one, a Uranus orbiter is the logical choice after Galileo and Cassini. Shorter flight time and many more moons with unmapped hemispheres, and a chance to dispense with the 'blue-green cue ball' image that has existed since 1986. The equinox when both hemispheres are illuminated is approaching as well.