How fast can we go with current rocket technology?

[crazyeddie]

I'm not sure if this is the right forum for this, but the discussion in the other thread on the difficulties of interstellar travel got me wondering. What's the fastest speed we could get a space probe out of the solar system, using current technology? Let's assume a useful payload would weigh 2 tons, or more than twice the weight of the Voyager 1 probe. Let's further assume the use of an Ares V booster, and the availability of either a NERVA-style nuclear third stage or an nuclear-ion engine. Or maybe even an small Orion-class booster (although I think that's an unlikely option, for a number of politial reasons). Throw in a gravity swing-by assist from Jupiter and perhaps another gas giant. Can any of you rocket scientists out there give us an estimate of how fast we could boost this probe, and how long it would take to get to Alpha Centauri?

 

[thnkrx]

I do have an additional thought to the OP's premise here that might help a wee bit: take eight or ten of the old Titan II (or is it Titan III?) rockets - the one that could put the entire fully fueled third stage of the rocket into orbit. Put the final stages of all these rockets, all fully fueled, into orbit, and assemble them into a multistage 'booster' for said probe (might take a few shuttle flights to pull this off). *Then* throw up a final unit - a fully fueled 'ion engine' also wedged into whatever space is available in one of these third stage units.

Thing is, once you are in earth orbit, you are halfway to anywhere you want to go in the solar system, at least in terms of energy expenditure. With all these extra rocket stages to give you a bit of a boost, you could build up quite a bit more velocity than anything launched from earth thus far - but I doubt that even with gravity assist, you'd be able to hit one tenth of one percent of light speed with this arrangement.

 

[MeteorWayne]

I don't thnk that what either of you suggested would count as "current" technology. The NERVA rocket doesn't exist. Neither do a hal+f a dozen Titans available to launch into LEO (And how do you launch them there?)

Pretty fanciful speculation, IMHO....

 

[crazyeddie]

I don't thnk that what either of you suggested would count as "current" technology. The NERVA rocket doesn't exist. Neither do a hal+f a dozen Titans available to launch into LEO (And how do you launch them there?)

Pretty fanciful speculation, IMHO....

NERVA rockets capable of up to 500,000 lbs of thrust were built in the 1960's, so it's actually old technology. We could build them today easily, and they have an ISP that's twice as high as the best chemical rockets. Testing them would be expensive, however, since we'd have to build an enclosed test facility to keep radiation out of the atmosphere.

And low-thrust ion-powered engines are currently powering the Deep Space 1 probe.

 

[thnkrx]

Titans are old, proven tech. As such they could be copied and built anew, should the right circumstances arise...maybe improved a bit.

I do know that when a lot of the old missile silos were decommissioned, there was a proposal put forth by a space activist group to strap solid fuel boosters to some of the missiles (which were put into storage) to help launch components of a space station into orbit. (The components being the final stages of the titan rockets. ) The idea was rejected as absurd, and I doubt the stored rockets even exist anymore. However, there may well be equivilents...

 

[DarkenedOne]

I'm not sure if this is the right forum for this, but the discussion in the other thread on the difficulties of interstellar travel got me wondering. What's the fastest speed we could get a space probe out of the solar system, using current technology? Let's assume a useful payload would weigh 2 tons, or more than twice the weight of the Voyager 1 probe. Let's further assume the use of an Ares V booster, and the availability of either a NERVA-style nuclear third stage or an nuclear-ion engine. Or maybe even an small Orion-class booster (although I think that's an unlikely option, for a number of politial reasons). Throw in a gravity swing-by assist from Jupiter and perhaps another gas giant. Can any of you rocket scientists out there give us an estimate of how fast we could boost this probe, and how long it would take to get to Alpha Centauri?

The Dawn spacecraft is the space craft with the greatest delta-v budget. Using its ion thruster it will change velocity 10 km/s. Combine that with the 11 km/s the rocket gave it to escape earths atmosphere you are looking at a top speed of around 21 km/s.

Now given the Dawn space craft is not designed for interstellar travel with that same ion technology one could achieve much higher speeds with the same technology.

 

[Boris_Badenov]

I don't thnk that what either of you suggested would count as "current" technology. The NERVA rocket doesn't exist.

Pretty fanciful speculation, IMHO....

These look pretty real to me.

 

[MeteorWayne]

Yeah, it's really... in a museum...

 

[Boris_Badenov]

Yeah, it's really... in a museum...

So are these, but we know they worked just fine. :twisted: