The Ice Giants Pre-Decadal Study group has proposed sending a mission to either Uranus or Neptune. Only one mission is likely to be approved due to a shortage of plutonium-238 for the radioisotope thermoelectric generators required for an outer solar system mission:
Uranus and Neptune have never got much attention from us – we've only passed each once and never hung around. But that could change. A NASA group has now outlined possible missions to make it to one of these outer worlds to gather data on their composition. This should teach us about them and similar planets in other solar systems.
"The preferred mission is an orbiter with an atmospheric probe to either Uranus or Neptune – this provides the highest science value, and allows in depth study of all aspects of either planet's system: rings, satellites, atmosphere, magnetosphere," says Amy Simon, co-chair of the Ice Giants Pre-Decadal Study group.
There are four proposed missions – three orbiters and a fly-by of Uranus, which would include a narrow angle camera to draw out details, especially of the ice giant's moons. It would also drop an atmospheric probe to take a dive into Uranus's atmosphere to measure the levels of gas and heavy elements there.
The three must-haves for each orbiter mission are a narrow-angle camera, a doppler imager and a magnetometer, while an orbiter containing 15 instruments would add plasma detectors, infrared and UV imaging, dust detection and microwave radar capability. The orbiter could be either a Neptune mission with an atmospheric probe, a Uranus probe of the same design, or a craft sent to a[sic] Uranus that ditches the atmospheric probe for the suite of 15 instruments.
Moon values: Neptune's Triton vs. Uranus's Titania, Oberon, Umbriel, Ariel, and Miranda (all rounded by gravity).
Obligatory grade school humor:
NASA wants to probe Uranus in search of gas
NASA wants to probe deeper into Uranus than ever before
Also at The Verge.
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NASA's Voyager mission was launched 40 years ago:
NASA's historic Voyager mission has now been exploring the heavens for four decades.
The Voyager 2 spacecraft launched on Aug. 20, 1977, a few weeks before its twin, Voyager 1. Together, the two probes conducted an unprecedented "Grand Tour" of the outer solar system, beaming home up-close looks at Jupiter, Saturn, Uranus, Neptune and many of the moons of these giant planets.
This work revealed a jaw-dropping diversity of worlds, fundamentally reshaping scientists' understanding of the solar system. And then the Voyagers kept on flying. In August 2012, Voyager 1 became the first spacecraft ever to reach interstellar space — and Voyager 2 is expected to arrive in this exotic realm soon as well.
The rest of the article is a Q&A with Voyager project scientist and former director of the NASA Jet Propulsion Laboratory Ed Stone.
Also at BBC and NBC. Image gallery at Ars Technica. A PBS special about the mission will air on August 23.
No missions have been sent to Uranus or Neptune since Voyager 2 visited them in 1986 and 1989.
Related: Pioneer and Voyager Maps to Earth: How Much of a Mistake?
Voyager's 'Cosmic Map' Of Earth's Location Is Hopelessly Wrong
Astronomers are still hoping for another mission to Pluto, or perhaps another Kuiper belt object:
A grassroots movement seeks to build momentum for a second NASA mission to the outer solar system, a generation after a similar effort helped give rise to the first one. That first mission, of course, was New Horizons, which in July 2015 performed the first-ever flyby of Pluto and is currently cruising toward a January 2019 close encounter with a small object known as 2014 MU69.
[...] Nearly three dozen scientists have drafted letters in support of a potential return mission to Pluto or to another destination in the Kuiper Belt, the ring of icy bodies beyond Neptune's orbit, Singer told Space.com. These letters have been sent to NASA planetary science chief Jim Green, as well as to the chairs of several committees that advise the agency, she added. "We need the community to realize that people are interested," Singer said. "We need the community to realize that there are important, unmet goals. And we need the community to realize that this should have a spot somewhere in the Decadal Survey." That would be the Planetary Science Decadal Survey, a report published by the National Academy of Sciences that lays out the nation's top exploration priorities for the coming decade.
New Horizons 2 was already cancelled due to a shortage of plutonium-238, which still reportedly persists. One proposed target was 47171 Lempo, a trinary system. The trans-Neptunian dwarf planets Eris, Haumea, Sedna, Orcus, Salacia, Makemake, and 2007 OR10 (the largest known body in the solar system without a name - with an estimated 1,535 km diameter) have all been discovered since 2002. Several of these TNOs have moons and Haumea was recently found to have a ring system.
Now that Cassini is dead, most new NASA missions are focused on Mars and Jupiter, leaving the solar system's "ice giants" relatively unstudied:
Planet Nine: 'Insensitive' Term Riles Scientists
The International Astronomical Union (IAU) famously reclassified Pluto as a "dwarf planet" in 2006. That decision remains highly controversial today, as made clear by the new note, which appeared in the July 29 issue of the Planetary Exploration Newsletter.
The note:
ON THE INSENSITIVE USE OF THE TERM "PLANET 9" FOR OBJECTS BEYOND PLUTO
We the undersigned wish to remind our colleagues that the IAU planet definition adopted in 2006 has been controversial and is far from universally accepted. Given this, and given the incredible accomplishment of the discovery of Pluto, the harbinger of the solar system's third zone — the Kuiper Belt — by planetary astronomer Clyde W. Tombaugh in 1930, we the undersigned believe the use of the term 'Planet 9' for objects beyond Pluto is insensitive to Professor Tombaugh's legacy.
We further believe the use of this term should be discontinued in favor of culturally and taxonomically neutral terms for such planets, such as Planet X, Planet Next, or Giant Planet Five.
35 researchers signed the note, including Alan Stern, principal investigator of the New Horizons mission.
Of more interest may be this proposal concerning future exploration of Uranus and Neptune:
Related: Uranus and Neptune Are Potential Targets for 2030s Missions
Another Trans-Neptunian Object With a High Orbital Inclination Points to Planet Nine
CU Boulder Researchers Say Collective Gravity, Not Planet Nine, Explains Orbits of Detached Objects
Planet Nine Search Turns Up 10 More Moons of Jupiter
(Score: 1, Funny) by Anonymous Coward on Tuesday June 20 2017, @11:21AM (9 children)
Instead, we need to work on machines that can build civilization on Mars, not check out the gas clouds on Uranus.
(Score: 0) by Anonymous Coward on Tuesday June 20 2017, @12:08PM (1 child)
If they rename it Trumpanus maybe he'll head the mission.
(Score: 1, Insightful) by Anonymous Coward on Tuesday June 20 2017, @03:29PM
Trump will rename all the planets:
Mercury: Little Hot-Headed Rubio
Venus: Cloudy Windbag Hillary
Earth: Golfland
Mars: Orangenia
Jupiter: Bigly
Saturn: Gold-Rings
Uranus: Fake Planet, doesn't exist, so sad.
Neptune: Future-Casinos, great view
Pluto: Where us Crats hang out
(Score: 2) by c0lo on Tuesday June 20 2017, @12:09PM (5 children)
Yeah, keep dreaming. Meanwhile, the Chinese will start production facilities on the Moon.
From which they can launch at a fraction the cost the launch from the depth of Earth gravity well.
The first civilization on Mars will speak mandarin.
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 0) by Anonymous Coward on Tuesday June 20 2017, @01:32PM (2 children)
Being tone based, Mandarin is by definition a shit language; on top of that, they employ logograms for their writing system—I mean, you can make this stuff up!
Mandarin will never be a prominent language outside of Chinese populations.
(Score: 2) by Azuma Hazuki on Tuesday June 20 2017, @05:18PM
Yeah? I'm learning it. It's a pain in the ass to write Chinese, but Mandarin (Putonghua anyway) is probably the easiest dialect. You want a hard dialect, try classical Cantonese.
I am "that girl" your mother warned you about...
(Score: 2) by c0lo on Tuesday June 20 2017, @07:33PM
Bingo. Continuing the logical chain of consequences, this means...(fill in the blanks).
https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
(Score: 0) by Anonymous Coward on Tuesday June 20 2017, @01:55PM (1 child)
Good luck with that. Meanwhile SpaceX happened which kind of killed the "Earth gravity well" problem rather quickly.
(Score: 3, Insightful) by mhajicek on Tuesday June 20 2017, @02:28PM
Not killed, mitigated.
The spacelike surfaces of time foliations can have a cusp at the surface of discontinuity. - P. Hajicek
(Score: 2) by takyon on Tuesday June 20 2017, @12:53PM
These missions are far under 1% the cost of doing any real world building on Mars, and need to be timed to take advantage of gravity assists. Our understanding of Uranus, Neptune, and their satellites is incomplete. Similar ice giants appear to be common in the galaxy so studying Uranus and Neptune which are relatively close by gives us a better understanding of other solar systems. Studying Triton could give us a winodw into the Kuiper belt since it is thought to be a captured Kuiper belt object. These moons are balls of resources that contain roughly as much water ice as rock and will become habitable after a couple of generations of Lunar and Mars colonies are developed.
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 2) by bzipitidoo on Tuesday June 20 2017, @11:57AM (3 children)
If lack of plutonium is crimping these plans, seems there ought to be alternatives, and there are. Americium-241 is the leading alternative.
Hope I live to see it. The article talks of the journey taking 14 years, and they might not launch before the 2030s. 30 years is a long time to wait, particularly when we all know this could be given higher priority. Really should have sent orbiters to the ice giants years ago.
Then there's Planet 9 to think about. The tech suitable for an orbiter of Uranus or Neptune is not adequate for Planet 9. Planet 9 at its closest is thought to be at least 6 times further out than Neptune, making for almost a century of travel time. It's more likely to be as bad as 40x the distance to Neptune. The RTG power supplies we use now don't last that long. Sending the orbiter faster makes it much harder to enter orbit. Don't think our tech is up to that mission.
(Score: 0) by Anonymous Coward on Tuesday June 20 2017, @01:35PM
Considering the size of "space", it might be a good plan to pinpoint planet 9 before trying to send something there ;) but still, plenty of exciting stuff to explore!
(Score: 0) by Anonymous Coward on Tuesday June 20 2017, @06:18PM (1 child)
Your biggest assumption is that Planet 9 exists at all.
(Score: 2) by takyon on Tuesday June 20 2017, @08:25PM
After listening to one of Michael Brown's recent talks, I'm on board.
If it's not real, it should become clear pretty soon since they have narrowed its hypothetical location to a very small patch of the night sky.
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(Score: 0) by Anonymous Coward on Tuesday June 20 2017, @03:49PM
Do we send the probe to the blue one, or the slightly bluer one?