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[RedKing]

It's a real shame they didn't bother to send a probe over there. Even a crash probe would have been fun to have a closer look of pluto. A rover would have been just fucking amazing but I imagine it would be really hard to land something there considering the speed of New Horizons and the lack of aero breaking.

Yeah, they'd need a delta-V of at least 9000 m/s to match Pluto. And a rather different approach path.

Could be done but they'd have to come at Pluto much slower, and thus the mission would take decades to get there instead of 9.5 years. Unless we get a better form of long-distance propulsion.

[Jopax]

It might be unviable and crazy but it just occured to me that they could try something like physical braking. Like, get on as close an approach as possible to it, like, kilometers away from the surface. Then fire off a number of very long cables with drillheads or something to lodge somewhere in the landscape. They then use the elasticity of the cables to slow down the craft enough for it to get into an orbit of sorts before attempting to land.

[Dutrius]

At those speeds, there is no known substance with enough strength to handle the stresses.

[Magistrum]

That would be awesome, but it would be hard to stop something as fast as horizon, the cables would most likely break or detach... Tough now I want it, it would be awesome.
Edit:Ninja'd!

[RedKing]

Hmm....wonder if a nuclear pulse propulsion would work as an effective brake. Something like Project Orion or Medusa, but instead of using nuke pulses to accelerate the craft, you'd use something like New Horizons' ion engines to get the ship there, then use nuke pulses to slow it down rapidly once its in the vicinity.

Be one hell of an engineering challenge, and scary to have to control all this remotely from 9 light-hours away. And because nuclear propulsion has such a PR negative, you'd almost have to build it in space to start with, even if you're not using the nukes for main propulsion.

[MonkeyHead]

Hmm....wonder if a nuclear pulse propulsion would work as an effective brake. Something like Project Orion or Medusa, but instead of using nuke pulses to accelerate the craft, you'd use something like New Horizons' ion engines to get the ship there, then use nuke pulses to slow it down rapidly once its in the vicinity.

Be one hell of an engineering challenge, and scary to have to control all this remotely from 9 light-hours away. And because nuclear propulsion has such a PR negative, you'd almost have to build it in space to start with, even if you're not using the nukes for main propulsion.

I would not trust nuclear pulse propulsion to not totally ruin any sensitive science packages on a craft without the extra radiation shielding making the mass prohibitive.

[LordBaal]

Hence why a crash probe would have been just as good as anything else. Also, is fun to blow stuff up.

A way in which would be possible to land a rover is that instead of passing by Pluto in a "orthogonal" path crossing its orbit, the probe take a "chase" approach or orbit transfer in which it rendezvous with Pluto travelling in the same direction and speed (well, not exactly it's same direction and speed) the planet goes in its translation movement, then take up orbit around Pluto and land whatever the fuck you want there. Problems I see:
1 Pluto orbit is pretty eccentric for a planet/dwarf planet
2 As you might guess, in order to do this the probe needs to get all the way there in a rather spiral path across the solar system, which means not only that it would take a fuckton of years to get there, but also gives more time for Murphy's law to act up.
3 There might be arachnids there.

[wierd]

You dont need a full nuke-- exactly.


I am thinking something like a hybrid of a farnsworth fusor with a laser ignition sitting "downstream" from an ion thrust engine.

The ion engine exhaust supplies a low pressure gas, which then is able to pass over the farnsworth fusor's cage. The laser pulse supplies sufficient energy to cause momentary fusion pulses.

We dont care about getting electrical energy back from the pulse, we just get a little extra kick from the fuel this way.

[Starver]

It might be unviable and crazy but it just occured to me that they could try something like physical braking. Like, get on as close an approach as possible to it, like, kilometers away from the surface. Then fire off a number of very long cables with drillheads or something to lodge somewhere in the landscape. They then use the elasticity of the cables to slow down the craft enough for it to get into an orbit of sorts before attempting to land.

Let's perfect the extremely low speed grappling of comet cores, first (note: first ever attempt failed¹).  But also note all the practical problems mentioned in http://tvtropes.org/pmwiki/pmwiki.php/Main/GrapplingHookPistol (and then the problems of getting lost in TVTropes...) and work out how to scale this to get multiple-multiple-kilometres of (as also mentioned, impossibly-strong!) cable and workable grapple and sufficiently powerful launch mechanism and/or grapple-end thrusters to end up attaching and all the control mechanisms needed to ensure sufficiently clean trajectories without tangling and all without significantly reducing the science package you're trying to get there... and then work out what you do when you have swooped down to mere kilometres from the surface with your over-speed probe, and are now not just swooping over the surface, with more than enough relatively velocity to get slungshot back out into space, but are now attached to the planet by one or more tethers like an already pretty much fouled up swingball around its post...

H-> .       Probe
|        `  .
|              .  Trajectory
| Tether      .
|                .
|                .
%----------\/--- Surface

Still, at least you weren't suggesting lithobraking...  Well, not until the end of the above.

(A quick "Tie and release" (or "tie and let snap", more likely) method could swap going-past-and-out speed for a momentarily different trajectory, but that would still be "more down than preferable", even if it's still a don't-hit-the-surface one.  So you do this with one tether, with enough control to get another fired, and another and another, in quick succession with gradually more 'retro' component, whilst carefully using just enough downward component to counteract the tiny component of 'upward fly-past velocity' you're going to possess... yeah, that'd be difficult.

...How about a big 'net' (needs to be bigger than Pluto, although the 'holes' can be fairly large within it) thrown out to the side of the vehicle to snare Pluto?  Then a very long cable (with staged 'breaking' components between folded segments keeping it initially short, until each pops whilst reducing the difference in velocity, until eventually you're at the end of an extended cable (many times long than those originally planned) with minor thrusts normalising the perpendicular velocity accordingly, and you can controllable reel what's left (again, hardly any science space left, after the huge weight of net and cabling, etc!) of the probe in...  and study a Pluto now permanently scarred by your (presumably quite tough) 'net' cables...

...no, that wouldn't work either.  Not to any advantage, anyway.)

The basic answer (until we come up with something revolutionary, which isn't harpoons) is to take a different orbit there (gradually matching the plutino orbit from roughly the same direction, rather than intersecting it at an extreme angle), necessarily taking longer time, such that you just need to slow down to 'match' the planet, using more conventional (or ideally low-thrust but high-thrust-to-weight) methods.


¹ But at least we were just trying to tie a spacecraft to a comet core, for study, not trying to tie a comet core to a spacecraft, to drag its away from a future Earth collision...  And currently it's working well.

[Icefire2314]

I'm still hoping for FTL travel. Physical travel past the speed of light has been disproven (though I believe it's possible, breaking the sound barrier was impossible until it was done), however the technology which is being researched which bends space looks promising. http://techland.time.com/2012/09/19/nasa-actually-working-on-faster-than-light-warp-drive/

Given the exponential rate of technological advancement, I'd love to see this in my lifetime. I want to visit another star in my lifetime.

[Starver]

(until we come up with something revolutionary, which isn't harpoons)

...I've decided what it is.  It's springs.  Or, to be precise, one big spring.  Under tremendous compression.  A big weight at the front and the probe at the back.  (You can do forward-looking science around the edges, or through a hole you leave in the middle.  Or just be prepared to turn the craft around, at will, obviously.)

On reaching Pluto (and reorientating, as necessary)...  BOING!  Weight bit flies forward at tremendous speed, and the probe bit significantly retards its velocity

Absolutely it'd work!  And I see no problems at all with this design!  No, siree!

[LordBaal]

though I believe it's possible, breaking the sound barrier was impossible until it was done

Way, WAY, WAAAAAAAAAAAAAAAYYYYYYYYYYYYYY different barriers.

[Dutrius]

(until we come up with something revolutionary, which isn't harpoons)

...I've decided what it is.  It's springs.  Or, to be precise, one big spring.  Under tremendous compression.  A big weight at the front and the probe at the back.  (You can do forward-looking science around the edges, or through a hole you leave in the middle.  Or just be prepared to turn the craft around, at will, obviously.)

On reaching Pluto (and reorientating, as necessary)...  BOING!  Weight bit flies forward at tremendous speed, and the probe bit significantly retards its velocity

Absolutely it'd work!  And I see no problems at all with this design!  No, siree!

I think I'll just leave this here. It seems pretty relevant.
Especially this section:

Spoiler (click to show/hide)

New Horizons is about the size and weight of a grand piano, and is currently screaming along at about 14 kilometers per second...
...in a hypervelocity impact, materials like metal aren't nearly strong enough to hold together. Instead of crumpling, they splash.

Spoiler: splash (click to show/hide)

I think it's safe to say that your massive spring would splash before you achieved any reasonable deceleration.

FAKE EDIT:
I've just re-read your post, and it seems that you are releasing the spring before you hit the planet. If the mass remains attached to the spring, then there is no point, the spacecraft as a whole would continue as it was before. If you intend on releasing the mass, it would be easier and more efficient to use a more conventional rocket instead.

[Starver]

I would not trust nuclear pulse propulsion to not totally ruin any sensitive science packages on a craft without the extra radiation shielding making the mass prohibitive.

Not to mention irradiating Pluto.  Poor plutonians!  (Unless, as mentioned, they're Arachnids.  In which case go ahead...  Probably won't do any harm.  Or good.  You'd need to get really close to actually wipe them out, and not just make them angry.)

[Starver]

FAKE EDIT:
I've just re-read your post, and it seems that you are releasing the spring before you hit the planet. If the mass remains attached to the spring, then there is no point, the spacecraft as a whole would continue as it was before. If you intend on releasing the mass, it would be easier and more efficient to use a more conventional rocket instead.

Or, if you'd re-read the post in the tone I wrote it¹, you'd realise that not only was I releasing the mass, but I was also utterly joking.

(But that What-If link was my initial reply option when I thought lithobraking was being suggested.)

¹ It looks like I need a sarcasm/wild-eyed kook font...