But if the computers were switched off, would thes high energy particles actually do any damage? And could the computers be adequately shielded anyway?
Yes. Some of these cosmic ray particles can carry huge amounts of energy. The most energetic ever detected carried the energy in a major league fast ball pitch packed into a proton. Shielding won’t help much either because when such an energetic particle smashes into it, it doesn’t just dissipate, it explodes into a shower of x- and gamma radiation, among other nasty stuff. These, in turn, can ruin solid state devices even if they’re off.
Despite the negative answers, this has been fascinating.
I think we’re only about 250 years or so from jump-gate technology. And there’s always cavorite.
Some sort of parachute would do the trick, I should think.
I have a disturbing feeling that that is already being heavily researched. Are you hoping that NASA will probe Uranus?
Don’t know if you were joking or not (“open a parachute in a vacuum … ha-ha!”), but this is an interesting point. Couldn’t you deploy a huge solar sail and use it to create drag on the solar wind?
I was joking, sort of, but yeah. It would take a while but if you aimed directly at the sun and started a couple astronomical units out when you unfurled, and didn’t care if you crashed into the sun, it just might work.
You woudn’t aim directly at the sun but at a point off it - possibly very far off it - to end up in the habitable zone (like the Earth) and you’d have to start very much further out than a few AU. For our solar system, the solar wind exerts a force of 10[sup]-5[/sup] Pascals (or Newtons per square metre) at 1 AU. This decreases with the square of the distance.
My mathematics is too rusty to do the calculations, but what size sail would you need to decelerate a 1 tonne probe from 0.1c to Earth orbit starting at the termination shock (94 AU - but call it 100 AU if it makes the maths easier)? And where would your initial aiming point be? Because don’t forget that you’ve also got to counter the star’s gravity.
You wouldn’t have to decelerate all in one shot. If you slowed down enough to get into some sort of orbit around the star, you could spiral in slowly but surely. It would take a long time, but probably not too long compared to travel time, and some of the time can be spend making observations.
Only if you can slow down enough on the first pass to turn your orbit into an ellipse. Otherwise, you swing on by in a flat hyperbola or parabola and never return.
Stranger
The health and safety guys are never going to allow it. Your call of “Fore!” is going to arrive well after the ball. Someone could get hurt.
So how long will V-Ger last? I saw an interview with a NASA engineer who was all a-giddy that they had built something that would last billions of years.
If true (noting Stranger On A Train’s response), it should be possible to launch using the same method - spiral out, accelerating on each successive loop.
-It will only work until your slingshots take you above escape velocity for the system, then you leave it forever. In which case I think it must be generally true that if you enter the destination system at more than its escape velocity, you’re going to have a hard time doing slingshot braking in it.
The structure might last billions of years, unless something runs into it. It’ll stop operating when the RTG peters out, though, and the electronics are already pretty fried by its swingby of the Jupiter, so I wouldn’t give the electronics their maximum expected operating time (though the system as a whole has far outlasted its expected mission duration).
Stranger
I’ll assume the velocity used to exit the system allows you to stop. And you can come in under escape velocity + delta vee for the first braking exercise.
I’ve got a book of formulas for computing orbits around somewhere. If I can find it, and have the time, maybe I can figure out some of the numbers.
I understand the problem. A plot point in something I was writing required our heroes to reverse using gravity assist. I was going to send them to a planet to do it, but it turned out that no planet conceivable had enough mass to make it possible, so I sent them to a star instead. (They had ftl travel, so no problems.)
Why not build your probe out of 50 computers where the first one is ON for 10 years then transfers control to the next one … ?
What device would control the switch-over? What if computer #4 got hit by a micro-meteor? What if the space-dingoes went after it?
You’d need enough computers on at one time so that the probability that the system is still working at the time of the switchover is very high. But the big problem is mass - can you afford to put 50 computers in. Don’t forget the additional hardware needed to control them and to interconnect them.
Back in grad school I took a seminar on multiprocessor systems, and we concluded that the interconnect was less reliable than the processors themselves. Today one of the big advantages of putting multiple CPUs on a chip is no external wiring.
A better reason for holding off would be to find a more attractive destination. Instead of devoting the world’s economy towards shooting a golf ball to Gliese 581 we should put the money into building solar-system-wide interferometers etc. to find the most interesting system in our vicinity.