Will there ever be another mission to Uranus and Neptune?

[pyro20]

Don't get me wrong, the extensive exploration of Mars and the Moon are great and I love Cassini. I'm also really excited about MESSENGER, Venus Express, and New Horizons.<br /><br />That said, missions to the two blues would be pretty sweet.

 

[Aetius]

People laugh at the name, but Uranus is a fascinating planet. I've always thought that it would be cool to build a large space colony in orbit around Uranus, in an orbit similar to Ariel's, but 60 degrees ahead of it. You could use a mass driver to deliver construction materials to the colony site (ice makes a nice building material at -330 degrees Fahrenheit), and still be close enough to send transatmospheric tankers to extract Helium-3 from the gas giant.<br /><br />You could create a paradise with that many resources at your disposal.<br /> <br />When humans travel to the other stars, I think they're more likely to find gas giants than Earth or Mars analog worlds, anyhow. Once we master the techniques of building space colonies near worlds like Uranus and the members of the Kuiper Belt, we can put that knowledge to use in a dozen other solar systems.

 

[Aetius]

I don't expect another mission to Uranus in my lifetime, though. <img src="/images/icons/frown.gif" />

 

[thalion]

I'd also love to see a mission to the "two blues" as you call them. For a long time there has been on-and-off talk about a Neptune orbiter, but it's just that for now; I know of no solid plans.

 

[vogon13]

A Cassini (or Galileo) type orbiter at Neptune could use Triton for orbit mods to make the tour more interesting. Close flybys of all the inner 'rock' satellites would be fascinating. The inner rocky sats do seem to have been neglected by Galileo, Cassini appears to be better, but still not comprehensive. Retro orbit of Triton probably a complicating factor in mission design, but the orbit guys love a challenge.<br /><br />Uranus is a little tougher. There is no moon massive enough for the big orbit manuevers we've seen with Galileo and Cassini. A possibility (I haven't done the math on this) would be to set up an initial orbit that passes Oberon closely and keep flying by it repeatedly and always adjust the orbit in the same direction.<br /><br />You could start with the initial orbit with a low point (relative to Uranus) around Puck. Then every pass by Oberon raises the perigee of the orbit a little. Eventually your low point encounters Miranda. Keep flying by Oberon and continue raising perigee to then encounter Ariel, Umbriel and Titania. <br /><br />This may be tough to do, keeping orbit synced to Oberon's period may not be easy (or even possible). May be easier to use Titania, but less mass makes this slow process even slower.<br /><br />Obviously, the craft for this trajectory will need to be long lived.<br /><br />Also, there will be many reasonably close flybys of the moons as the perigee slowly rises though the Uranian moon system.<br /><br />I would suggest naming the Uranus probe Herschel, and for Neptune, you could go with Adams and/or Leverier. Maybe the main craft could have one name, and the optional (but very desirable) Triton lander the other. Note- landing on Triton probably pretty difficult.<br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[pyro20]

I've read that a mission to Neptune would take 35 years. Is that accurate? I mean, how could it be when it will take 10 years to get to Pluto.<br /><br />How long would a trip to Uranus be?

 

[henryhallam]

Without actually checking, it could be that Jupiter isn't lined up right w.r.t. Neptune for an efficient slingshot. So you either have to take a less efficient Jupiter slingshot that takes longer to reach Neptune, or you have to launch directly into a near-Hohmann transfer to Neptune which is both slow and takes a large rocket to do the job (actually, I'm not sure if it's even possible to launch a decent payload direct into that high a solar orbit).

 

[thalion]

re Pyro:<br />A flyby can use a relatively short, direct trajectory, like the upcoming New Horizons mission. However, an orbiter must be travelling relatively slowly relative to its target planet, or else it will use an inordinate amount of fuel to brake into orbit.<br /><br />The most fuel-efficient trajectory--as well as the slowest direct option--is a Hohmann transfer ellipse. Calculating travel times is relatively simple; for an outer planet mission, just calculate the semimajor axis for an elliptical orbit with a perihelion at the Earth's orbit and the aphelion at the target planet's (for Neptune, this would be about 15.5 AUs), and then calculate *half* the revolutionary period from Kepler's Third Law (a^3 = p^2). For a Neptune Hohmann, this would be almost 31 years, in line with the estimate you cited.<br /><br />Of course, there are more fuel-costly (but shorter) routes, and there's always the handy gravity-assist, but in any event the slow boat to Neptune would be slow indeed. Personally, the farthest I'd use a Hohmann transfer would be Uranus; the 16-year transit would be a long, long time, but at least theoretically bearable.

 

[CalliArcale]

The other problem with Neptune orbiters is that you have to not just get there, but get there in such a way that you can actually insert yourself into orbit. Voyager was going WAAAAAY too fast for an orbit insertion. This is why Cassini took so long to get to Saturn, despite launching on a more powerful rocket than Voyager. It had to arrive on the right path, not just arrive.<br /><br />Uranus orbit is even more complicated, because Uranus has the most extreme axial tilt of any of the major planets. <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[apollo_18]

A probe to Uranus or Neptune would be a good testbed for a Solar-Sail propulsion system. Slow but steady acceleration over a long period, doesn't need to carry huge amount of propellant, so more room for science instruments.<br /><br /> I seem to remember reading somewhere that a solar-sail can be configured to decelerate a craft too, so even an orbital mission would be possible.

 

[apollo_18]

Lol, just after posting that I saw this on the SDC main news page.............<br /><br /><br />http://www.space.com/missionlaunches/050523_comsos1_delivery.html

 

[CalliArcale]

I've been eagerly awaiting Cosmos 1 for a few years now. I'm thrilled that they've announced a launch date! I just hope this one goes better than the suborbital test they did a while back. The first spacecraft, with only a single solar sail "blade", was meant mainly to validate some of the basic engineering. But the Volna booster failed, and it never even got a chance to try. On June 21, I'll be crossing my fingers for them! <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[redgryphon]

Alan Stern, the PI for the New Horizons mission to Pluto, has proposed a New Horizons II based on the same spacecraft design, for a mission to Uranus via Jupiter. Now is a good time to go because Uranus is near equinox, ie with the ring plane pointing towards the Sun, which means all the surface of the planet and moons would be iluminated. You can find more about it, including some useful links at http://www.unmannedspaceflight.com/index.php?showtopic=715 <br /><br />Stern's view, to which I'm sympathetic, is that it is better to launch a flyby now, and get a lot of science for half a billion dollars or so, rather than wait for the $3 billion flagship mission in twenty years.<br /><br />I do think there will be a mission launched to the outer solar system within the next two decades. A Neptune orbiter was a high (albeit long term) priority under the Decadal survey for solar system exploration. So the demand for it is there. There's just a lot of missions in the queue ahead of it.

 

[redgryphon]

You can download the Decadal Survey (which is essentially the consesus opinion of the planetary science community) here:<br />http://www.nap.edu/catalog/10432.html <br /><br />See especially Chapter 4 and pages 196-7

 

[thalion]

Count me in Calli, as one of the guys who's going to be sweating bullets on June 21 for Cosmos 1...

 

[ehs40]

it may be hard to slow down but if nuclear power were used there would be enoff energy to do all kinds of things but i bet once nasa is allowed to use nuclear power widely uranus and neptune will will get there long awaited visit.