NASA has boffins working on plans to send a nuclear-powered robot boat to cruise the chilly patio-gas oceans of Titan, ice moon of Saturn. The hydrocarbon lakes of Titan's north polar region. Credit: NASA Arr there, Mr Spock. Lay me a course close-hauled fer the Sea o' Krakens, d'ye see? Ellen Stofan, formerly a boffinry …
"Place a relay satellite some 200 million miles or so above the north pole of the sun. With this we'd have year round comms with all the exploration vehicles."
The first is that its practically impossible. Sats don't just sit in space. They have to orbit something. You would have a polar orbit over the Sun, and that would take it over the north pole, then all the way down over the south, and back again, etc.
Things stay in orbit by moving so fast sideways that they fall _around_ the object they're orbiting.
If you stop, you fall straight in.
So if you stop over the top of the Sun... Down ya go!
There is a way around this called a statite, which is where a giant solar sail can stop over the sun and use solar radiation pressure to stay aloft, but nevermind that.
Nevermind that because the whole thing is superflous.
You see, all the planets orbit in big ellipses, but these ellipses are tilted differently.
So the Sun is very rarely actually in front of the other planet.
So communication blackouts are few and far between.
When blackouts happen, its easier to just wait it out.
Patience is _always_ cheaper.
...Which is also why we use these 7-10 year trajectories even though we have the technology to send probes dramatically faster.
@ Pirate Dave: I presume the issue would be a lack of oxygen for combustion. Bringing enough of it or equivalent ox agent to get a useful amount of power would result in a payload of rather over 20-odd kg.
@ Led Boot: My thoughts exactly. They have done similar before with LRO/LCROSS and Cassini/Huygens (sp?) but in both those cases the orbiter had another job too. It would seem a bit stupid just to send the sailing contraption as it sounds risky enough and orbiters are pretty proven at this stage. Maybe some Reg spacegeek can enlighten us.
'If you're going to the trouble of sending a nuke powered ship all the way out there, why not attach some sort of satelite you can fling into orbit so we can get data back all the time?'
You'd have to slow it from interplanetary velocity which would either need an enormous amount of fuel, or you could try aerobraking in Titan's atmosphere which would be nerve wracking.
As for probes doing more than just sitting there; in 1986 the Soviets put balloons on Vegas 1 and 2 to take readings of the Venusian atmosphere. They confirmed it was pretty bloody nasty.
Tick: Probe on Titan, we need that.
Tick: Radioisotope-powered probe, the greenies can go jump.
FAIL: Blown about by the wind. Right; get yourself a small dinghy, say a Laser, go out in any bay on any day, and leave it uncontrolled. Observe what happens.
EPIC FAIL: photos from probe showing only the perpetual cloud of methane steam from the ocean boiling due to the heat flow from the probe.
Since we seem to be quoting the Guide:
Eddie, the shipboard computer (backup personality): "It'll all end in tears, I know it!"
E 2: You explain what you want to achieve by placing a satellite 200 million miles above the north pole of the sun, but you fail to explain, or I fail to understand, how it is going to achieve it.
I assume that you think that it from there should have direct line of sight to both earth and the vehicle, but exactly why it should I fail to see. Saturn is close to one billion miles away from the sun. So 200 million miles above the sun would give an angle of about ten degrees between the orbital plane of the earth, Saturn and the satellite. How that is going to help, I am not sure.
Anyway, how do you place a satellite above the north pole of the sun? Last I checked you could place things in orbit, not at fixed points in space.
Pirate Dave: Two questions: Where do you want to take the oxygen from? and: Even if you had oxygen available you would need to heat up the fuel several hundred degrees to ignite it and then it would burn at even higher temperatures. How do you plan to build the engine so it can endure that kind of temperature difference? We are talking about an environment where the temperature is one third of that on earth.
and if it could arrive in 2022 that's surprisingly early for such an ambitious mission. If they're going to send a probe that far though, why not get as much science out of it as possible and send a wheeled rover as well? After all, with the expense of going that kind of distance and all the other destinations in the outer solar system, it'll probably be a long time before another mission goes to Titan.
Would a RTG really be practical in seas of liquid hydrocarbons? Surely it'd need a lot of (heavy and expensive to launch) shielding to prevent it evaporating the sea around it.
A ship, with a nuke, sent to Titan? That can only be a good thing. Hope they'll find the money for that (and yes I'm OK with robotic space exploration as long as it's beyond the Asteroid Belt)!
@Pirate Dave "If the probe is floating about in a sea of LPG and such, err, why not send it up with the generator hooked to an internal combustion engine capable of combusting LPG? "
And you'll get the oxygen where for that?
I've no doubt the probe will eventually float but won't hydrocarbons at -180C be quite sticky? after all methane melts at -182C so its only just melted, Ethane -183C etc. its not like water 0C solid, 1C liquid. and we are assuming its -180.. what are the errors in this measurement. could it be -190.? A solid surface awaits the probe in that case.