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NASA Wants To Probe Deeper Into Uranus Than Ever Before
Up until now, NASA has never paid too much attention to Uranus – but now the space agency wants to take a good, long look. And one of the things it might be investigating is all that gas. A NASA group outlined four possible missions to the ice giants Uranus and Neptune.
These missions include three orbiters and a possible fly-by of Uranus. The planned probes would take off in the 2030s, New Scientist reports.
[...] One of the proposed missions includes a fly-by of Uranus, which would include a narrow-angle camera – and a probe which would drop into Uranus's atmosphere to measure gas and heavy elements. 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.
(Score: 5, Interesting) by KilroySmith on Friday September 28 2018, @03:13AM (9 children)
Why is this so hard?
Why can't we build a dozen, or two dozen, identical satellites and launch them into orbit around Venus, Mars, Saturn, Jupiter, Uranus, Neptune, Pluto, and a few other interesting moons (Europa, Ganymede) or KBO's? Build them with identical optics for planetary study, perhaps with different-sized Solar arrays and/or communications dishes to account for distance, and a box to contain an atmospheric probe (perhaps big enough for a rover on the rocky planets, an atmospheric sampler for the gas giants, or an otherwise objective-specific payload). Contract with SpaceX for Falcon Heavy or BFR transport, and just do it. They'll be cheaper by the dozen, I'd imagine, and we could get a full set of modern orbiters around all the interesting spots in the solar system. Don't worry too much about time - if you can build and launch twelve satellites by 2030, you can wait 5 or 10 years for the Neptune or Pluto orbiters to get into position, because you'll have to wait longer than that to get a planet-specific mission planned and executed.
(Score: 2) by PartTimeZombie on Friday September 28 2018, @03:17AM (1 child)
I have often wondered the same thing. There must be some reason no-one does this, but I can't think what it might be.
(Score: 0) by Anonymous Coward on Friday September 28 2018, @04:50AM
Maybe because when NASA landed on mars they found an american flag already there enclosed with a note explaining how beards mimic cranial nerve damage to defeat lip reading.
(Score: 4, Insightful) by takyon on Friday September 28 2018, @04:10AM (3 children)
The proposed missions could be comparable in cost to Cassini. So, in the $2-3 billion range. Obviously, we need to fund SLS/Orion pork rather than science.
https://www.theverge.com/2017/6/16/15810926/nasa-uranus-neptune-mission-voyager-2-spacecraft [theverge.com]
See also the table following that paragraph.
Timing does matter because there is an ideal launch window [newscientist.com] which could be missed.
Launch costs probably aren't the biggest cost component of such a mission. At most, NASA is going to pay what, $300-400 million for the launch on a Delta IV Heavy? But using Falcon Heavy or BFR could have unexpected cost benefits, like allowing cheaper "big and dumb" spacecraft instead of optimized lightweight spacecraft.
I think what could be really helpful is a mass-produced satellite or orbiter, as you mentioned. You just create carbon copies so that you can order duplicate parts and simplify build time and testing. Then send them to target objects.
...And what I really want to see is a cheaply-built, lightly tested Hubble-wavelength space telescope. Imagine if you fit as large of a telescope as possible into the BFR payload fairing, but without using an unfolding set of mirrors like the James Webb Space Telescope (or its planned successor) does. You could get an ~8-meter aperture telescope into the BFR, as long as it is ultraviolet/visible/near-infrared and doesn't require a massive heat shield. Then you make 10+ copies of this telescope, build them as fast as possible, with the intention of launching all of them into low-Earth orbit. Don't test them for years on end like JWST, but build in the capability for manned or robotic servicing. Even if a couple of them fail, it should be fine.
If done right, you could get 10 better-than Hubble, better-than-JWST (in terms of aperture, since wavelengths wouldn't match) space telescopes for a fraction of the total cost of the Hubble mission. This would be an incredible thing, even if it wasn't the 15-meter telescope that astronomers really want. We could even donate or rent some of these (space peace gesture with China? [wikipedia.org]) with plenty of science time to spare. Hubble is utilized constantly, and will be until the day it dies, and it only has a 2.4-meter aperture. Just imagine what could be done with ten 8-meter aperture telescopes, all launched around the same time.
One problem is that NASA is fairly determined to ignore BFR, until such time that it exists, although there has been a LUVOIR BFR study [soylentnews.org] which is encouraging. As for the Falcon Heavy, despite having a mostly successful launch, it has few customers (the Air Force is one), and there have been mixed signals about it being used instead of the SLS (it could be used to build the LOP-G, just not carry astronauts at the same time):
After the Falcon Heavy Launch, Time to Defund the Space Launch System? [soylentnews.org]
President Trump Praises Falcon Heavy, Diminishes NASA's SLS Effort [soylentnews.org]
NASA's Chief of Human Spaceflight Rules Out Use of Falcon Heavy for Lunar Station [soylentnews.org]
NASA Administrator Ponders the Fate of SLS in Interview [soylentnews.org]
SpaceX's Falcon Heavy Could Launch Japanese and European Payloads to Lunar Orbital Platform-Gateway [soylentnews.org]
I don't think Trump is going to pay much attention to the situation. NASA Administrator Bridenstine should be the focus.
Unfortunately, Congress is calling the shots with regards to SLS. And although it could be a fantastic idea to use Falcon Heavy instead of SLS, Falcon Heavy is still a rocket they can ignore. BFR is not a rocket they can ignore. The payload is too big (100 metric tons to various destinations with in-orbit refueling) and the rocket is too cheap (when fully reused). But they can and will ignore BFR as long as it is still on paper or being built.
Finally, another, potentially more palatable, idea for cheap solar system exploration would be to use CubeSats [wikipedia.org]. You may recall that the InSight mission to Mars included two 6U-sized CubeSats [wikipedia.org], which became the first spacecraft in that form factor to operate in deep space. Why not scale it up slightly (12U?) and make it a primary, cheap payload sent to Venus, Mars, etc.? Although if you want to send it to Jupiter, it likely needs massive solar panels, and further destinations will require a radioisotope thermoelectric generator.
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 0) by Anonymous Coward on Friday September 28 2018, @06:03AM (1 child)
> Then you make 10+ copies of this telescope, build them as fast as possible, with the intention of launching all of them into low-Earth orbit. Don't test them for years on end like JWST, but build in the capability for manned or robotic servicing. Even if a couple of them fail, it should be fine.
What makes you think all 10 of them wont fail due to lack of testing?
(Score: 2) by takyon on Friday September 28 2018, @06:50AM
Because NASA engineers can estimate the risk of failure or at least come up with a list of things that can go wrong. They could test spacecraft in some ways without adding years of delay prior to the launch date. They could launch them one at a time as they build them. Without the unfolding mirror design or sunshield of the JWST, a low-Earth orbit UV-VIS-NIR telescope should have fewer points of failure.
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 1, Informative) by Anonymous Coward on Saturday September 29 2018, @07:27AM
Launch windows are getting less critical as high-impulse/low-thrust propulsion (ion engines of various types, and with various power sources) moves into maturity. The currently-proposed missions only include SEP (solar-electric propulsion -- like Dawn, but scaled up to 25kW) for a Neptune mission; because of decreasing solar intensity, they're building it as a discardable stage to be ditched at 6AU -- for this mission profile, there is one Earth assist and one Jupiter assist. They also developed SEP profiles for Uranus missions, with two Venus assists and an Earth assist, but no Jupiter/Saturn assist, and thus no worries about Jupiter-Uranus orbital alignment. They were deemed too expensive (compared to the chemical-only, Venus-/Earth-/Earth-/Jupiter-assist programs) for only shaving one year off the flight time. (The Neptune mission, on the other hand, was impossible without SEP, given the Delta-IV Heavy as the best launch vehicle under consideration.)
What are our other options? How could we get beyond 6AU with ion propulsion, to reach Neptune with no Jupiter flyby?
Where our current favorites, 238Pu and 241Am, only offer a single α decay (~5 MeV) before hitting a long-lived (t½ > 105y) daughter isotope, we could go with something like 227Ac -- the immediate decay (0.05 MeV β-, t½=22y) is underwhelming, but then there's a whole cascade of short-lived (t½<20 days) descendants going through no less than 5 α decays (6-7 MeV each), and a couple β- (~1.4MeV each).
Now to be sure, 227Ac's t½ is a little short for the outer planets -- I imagine you'd have to start with more heat than your thermoelectrics can handle, and a radiator to ditch the surplus heat, and progressively diminish the effect of the radiator (by collapsing it or reducing coolant circulation) as the decades pass. And the various β decays, while not essential for power, do pose a serious shielding problem -- though if you place the RTG(s) on a boom, most of that shielding can be jettisoned once the spacecraft leaves Earth's vicinity, keeping just enough to shade the spacecraft. But it's just an example of how limited 238Pu and 241Am are; with 6x the energy per atom, and 4x the decay rate, you save enough in mass to make up for whatever shielding and variable heat management you need to do.
Another potential is 248Bk; similarly short t½ but shorter decay chain (only 2 α decays) before it stalls on a long-lived isotope.
There's also another direction, that of using lighter elements to get more power per mass. For instance, 44Ti (electron capture, t½=60y), decays to 44Sc (1.5 MeV β+, t½=4h). Again, there's a β shielding issue, and this time, as with light elements generally, the bulk of the energy comes through β decay, so you don't get significant thermal power if you let them escape. But it delivers about 1/3 the power of 238Pu for less than 1/5 the mass, or approximately double the power per unit mass. Not sure that's enough gain to cover the mass of shielding at a currently-useful scale, but keep in mind there's a square-cube relation between a sphere of radioisotope and a given thickness of shielding; it gets better as you scale it up.
For these proposed missions, we're not quite far enough along, so launch windows still matter, and will probably still matter by the time it would fly. But by 2040 or so, I think these once-in-decades launch windows will be a thing of the past.
(Score: 2) by bob_super on Friday September 28 2018, @05:17AM
So far each probe has been custom-designed for its target, because each target has a very different set of problems and things we'd rather focus on.
If you do a Voyager/Pioneer-style flyby, then you can use common hardware. As soon as you try going into orbit, the worst parameter of each planet would be a constraint on all the probes.
Add giant delays and still quite sizeable budgets (because everyone wants their stuff on a once-in-a-career mission), and you're back to square one.
We already touched on this about 1 JWST vs a bunch of telescopes, a while back. Until we have a cheaper launcher, cheap support, and guaranteed agency budgets to allow many missions, every probe is treated as probably your only opportunity, price and delays explode...
(Score: 0) by Anonymous Coward on Friday September 28 2018, @07:17AM
Why did it take so long to get rid of the shuttle? Or build a re-usable rocket?
(Score: 1) by khallow on Saturday September 29 2018, @01:06AM