[Christian.Muys (OP)]

I have some remarks and 1 question about traveling through space.
In the past 50 years, mankind have spend tremendous amounts of money for moving machines and sometimes humans through space, with proportionate disappointing results, and worst of all, most limitations are still the same :

• a great lack of power to go with (with repercussions to maximum loading (for man, equipment, water and food),  speed, manoeuvrability, communicationpower,...)
• vulnerability to other matter like spacedebris, dust, rocks,... and to radiation
• to slow communcation and thus unsafe if unmanned on great distances, to little flying range if manned

And yet, even before Neanderthals walked on earth, there flew naturally space-'ships' around, passing earth as well as many other planets. I am of course talking about the comets, which could give :

• a free ride or flight across very long distances
• free shelter against collisions with minor rocks and dust, maybe against radiation if it comes from a specific direction
• free water (very old and dirty ice  that has to be processed, but so does recycling water that comes from earth)
• energy source 1 : that same dirty ice, is still water that can be used to produce hydrogen
• energy source 2 : comets do lose continually matter while travelling at high speed, so if a stationary equipment processes the 'exhaust' of the comet, like turbosystems in cars do, or use the flow in some manner to power an alternator, one could speak of free energy for once.
• a very predictable and safe route (otherwise those comets wouldn't be around for so long), so less need for slow longdistance communication.

-
I know that landing a spaceship from earth, on a highspeed comet, would be difficult, but at least it is possible for unmanned and small machines that could prepare a place to land a bigger ship.
My only question is, apart from huge budgets, what keeps scientist from trying ?

I do hope one can forgive my not so proper English, as it is my fourth language.

[ukmicky]

Comets only move at high speed as they approach the sun once they start moving away their speed drops

[Christian.Muys (OP)]

Comets only move at high speed as they approach the sun once they start moving away their speed drops

Could you be a little bit more specific ? What speeds are you thinking off ? Maybe in comparison with a spaceship like one uses today ?

[neilep]

Hi Christian,

Genetics and Cybernetic implants will play a big role in the helping the ' human ' body fight off all the deadly radiation during long term space flight....perhaps even nano bots so small that they instantly either defend against radiation or perform constant maintenance.

....flying in space is terminal !...(over a long period of time)

[daveshorts]

There are various problems with this:

The biggest one is how do you hitch a ride on the comet, if you match speed with it you will use as much fuel as you would to put yourself on it's orbit anyway. If you didn't match speed with it, you would hit it at many km/s and end up as a load of very hot gas....

The hydrogen is only a useful power source if we can build a fusion reactor, and doing that for plain hydrogen is hugely more difficult than for deuterium/tritium - if we have a small light fusion reactor then we can probably just build a space ship with big enough rockets to go where we want anyway.

The only real advantages are as a pile of resources (water carbon etc) that is already going in the direction you want and hence the option of burrowing into it to act as armour against meteorites... both of which are not really useful unless we have a huge amount more technology.

[Christian.Muys (OP)]

Thank you for your response, Daveshorts
"Quote : The hydrogen is only a useful power source if we can build a fusion reactor..."
I don't follow. Since the 70's there are experiments going with buses and cars driving on hydrogen, and at least Mercedes Germany has today something usefull. I wasn't exactly talking about a huge powerreactor, a small generator would produce allready far more energy than any (fragile) sunenergyscreen.

"Quote : The only real advantages are...."
That's one of the reasons why spacescience got and is getting nowhere : many people keep looking in a straight line, surprising little imagination.
At large distances, to unmanned ships, communication is so slow, it has less and less sense trying to pretend one is really in control of steering and navigating and doing the right reactions to sudden things internal (hardware and software errors) or external (you name it). Also if anything,  goes wrong with hardware or software, the whole ship is lost and keeps flying in a uncontrolled direction (most likely away from earth).
If however you have a small, sheltered equipment on a comet, it WILL come back in whatsoever condition, so any scientific experiment will come back.

P.S. : Also, I get many reactions around the world (other forums, same question) with the same surprising words : 'what's the point flying around with so called 'no particular target' ' ? My answer to that is the very same : where is the imagination of the scientists ? Does everybody really think there is nothing to do nor to see on the route of comets ?

[daveshorts]

You can power busses on hydrogen, but only by reacting it with oxygen and turning it into water. Oxygen gas is quite easy to get hold of on earth because all the plants are making it, however on a comet there is no oxygen gas and all the oxygen atoms are already part of water or carbon-dioxide, so whilst you could get oxygen and hydrogen out of these it would use more energy than would be released.

[Christian.Muys (OP)]

Absolutely right daveshorts, but as I mentioned before, I thought of using the exhaust of the comet as an (big) energysource, to make more usable energy like hydrogen for combustion or electricity for many purposes. Not saying it is easy, but if there would be large budgets to spend, I don't see no reason why it couldn't be done.

[daveshorts]

What exactly do you mean by stationary equipment?

[Christian.Muys (OP)]

Quote "What exactly do you mean by stationary equipment?"
Thank you for being curious. I can not describe exactly what it should be, only a rough description. It could be a construction, likewise a generator that is driven by the flow of water here on earth on a storage lake, only much stronger. Another way could be a kind of magnetic field, where the exhaustparticles can flow through ; if they are negative or positive charged, in which case it should behave like a current through a stationary magnet, causing a movement in this kind of a motor (of course, that stream shouldn't flow just right through it, but be forced to follow a certain trajectory, in analogy with a classical electric motor, but I think there is not much of a change building hardware that can withstand such huge mechanical powers.
The main idea is extreme strong hardware, anchored on the comet, that uses the flow of leaving particles to drive a generator, be it mechanical, be it electrical.
With the power you get, you can use it right away, but even important, there has to be power accumulated, as the cometexhaust is not constant, an keeps decreasing when moving from the sun. Hence the idea of splitting the dirty ice in hydrogen, because that is storable for later use.
P.S. : a userreply on another forum let me know that there has been several sciencefictionwriters who have explored the idea of 'riding a comet'. I haven't read English literature and so I can't judge the value of their idea's, but I wouldn't be surprised if they had good idea's. Hopefully, some scientists read such literature and get some fresh idea's instead of losing time and money with projects like ISS (I heard a large podcast with a highly respected pioneermember of NASA itself, it was shocking what (and why) he thought of the scientific value of many NASA-projects. If you insist, I try to look it up and drop the link later if it still exists on the web, or send you the mp3 if I still have it).