How Long To Get An Unmanned Probe to 1000 to 2200 AU?

Dayton Kitchens · 2005-12-22 09:55:15

I've read that an unmanned probe sent out to between 1000 AUs and 2200 AUs would be able to use the suns gravity as a lense to get detailed images from other solar systems.

Theoretically, such images would be so detailed that they could actually show builidings (if any) and similiar sized surface details on planets in other solar systems.

Does anyone have any idea how long it would take to get a probe like that to the desired distance? Assuming advanced nuclear engines of some kind at least?

Palomar · 2005-12-22 10:06:41

Assuming advanced nuclear engines of some kind at least?

*I was wondering what sort of propulsion system you had in mind, when I saw the subject line. Sorry, I don't know the answer to your question. But I'll look forward to replies from the Brainiacs here. Hopefully our resident Mr. Spock from Canada will chime in.

--Cindy

C M Edwards · 2005-12-22 14:44:30

I'll look forward to replies from the Brainiacs here.

Not much of a challenge, really. *sniff*

( )

A probe like that could be built using modern technology. The main design problem isn't the distance but rather the speed required, so it'd need something like an ion drive to get the needed escape velocities for Earth and the Sun (about 3.2 km/s and 11.5 km/s, respectively), then put on the velocity needed to reach 1000+ AU in a reasonable time. I think about 3.5 km/s should do it, but that's just a personal preference based on how long I want to wait for the probe to arrive. (This could be done at less than escape velocity, but not in less than a decade.)

All told, that's about 18.2 km/s delta-v. A 500 kg probe with an exhaust velocity of 20 km/s could do that using about 750 kg fuel. (There would, of course, be no fuel to stop upon arrival.)

Running on about 600 Watts, that probe could manage an average thrust of 0.04 N. The probe's acceleration would be so small that by the time it finished accelerating to 18.2 km/s, it would nearly be at 1000 AU. However, with continuous operation, that's all it would take to complete the trip in about 10 years. The bulk of the distance would be covered in the last three years, after escape velocity is exceeded, and the probe would reach 2200 AU in only a year and a half after that.

600W for 10 years isn't too much to ask from a set of four RTG stacks just like the one flying on the Cassini probe right now. The rest of the probe would have to hold together for that long, too, though. It's a tall order, but not impossible, and no advanced nuclear propulsion or even particularly new developments would be required.

Dayton Kitchens · 2005-12-23 07:54:53

So you're saying RIGHT NOW we could build an unmanned probe that could get to the 1000 AU mark in only TEN YEARS with no real advances in technology?

I'll assume you're correct.

My next question is................why isn't NASA seriously proposing this?

It doesn't sound like a budget buster to me.

And why spend money on space telescopes like the Terrestial Planet Finder or Inferometer or whatever its called when a probe that could take advantage of gravitational lenses would be much more effective?

C M Edwards · 2005-12-23 14:34:08

My next question is................why isn't NASA seriously proposing this?
It doesn't sound like a budget buster to me.
And why spend money on space telescopes like the Terrestial Planet Finder or Inferometer or whatever its called when a probe that could take advantage of gravitational lenses would be much more effective?

It isn't a budget buster, and there's lots of things we'd like to know about that region of space. However, I don't blame NASA for the absence of a 1000+ AU gravitational lens telescope.

IMHO, there are problems with the idea. There's the various human-created problems of actually getting three or four RTG stacks to orbit. Then, there's the fact that a lot of alternatives (Terrestrial Planet Finder, etc.) could both be ready sooner and have equivalent resolution.

Yes, equivalent resolution, and cheaper, too. A 1000+AU Grav Lens scope could have magnification that was literally out of this solar system, but for a single probe its effective "lens" would only be a few times wider than the sun as viewed from 1000+ AU. I could maybe see it's superiority for observing in gamma rays, neutrinos or something that modern materials science can't yet make a better scope for, but not for optical or radio observations. Getting a larger effective lens would require sending more probes, and you might as well do that close to home.

Very long baseline interferometers would benefit from the extreme distances involved, but they don't have to be that extreme. And anyway, you couldn't use it for extending a gravitational lens baseline because the scope on the other end from the probe either wouldn't have the benefit of the gravitational lens or would be looking in a different direction.

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#1 2005-12-22 09:55:15

Re: How Long To Get An Unmanned Probe to 1000 to 2200 AU?

#2 2005-12-22 10:06:41

Re: How Long To Get An Unmanned Probe to 1000 to 2200 AU?

#3 2005-12-22 14:44:30

Re: How Long To Get An Unmanned Probe to 1000 to 2200 AU?

#4 2005-12-23 07:54:53

Re: How Long To Get An Unmanned Probe to 1000 to 2200 AU?

#5 2005-12-23 14:34:08

Re: How Long To Get An Unmanned Probe to 1000 to 2200 AU?

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