Interstellar Probes

Today I was thinking about the possibility of an interstellar probe. Is it possible for us to launch a probe that will reach another star within my lifetime, using today's rocket technology?

In order to answer this question, I read a bit about the nearest thing that we have to interstellar probes. So far, we have managed to launch five objects fast enough to escape the Sun's gravity: Pioneer 10 (1972), Pioneer 11 (1973), Voyager 1 (1977), Voyager 2 (1977), and New Horizons (2006). These probes are all moving so fast that once they leave the Solar System, they're never coming back.

New Horizons is currently travelling away from the Sun at just under 20 kilometers per second. Suppose that New Horizons was travelling toward the nearest star system, Alpha Centauri, and that it could keep up its current speed the whole way there. The nearest star is 4.37 light-years away. That's roughly 41.3 trillion kilometers away. Under these very ideal circumstances, it would take over 65,000 years for New Horizons to get to Alpha Centauri. Apparently, sending a probe to another star within my lifetime is not as easy as I thought it was going to be.

It turns out that if we want to send a probe to a nearby star anytime soon, a dinky little chemical rocket just isn't going to do it. We need to bring out the big guns. A few groups, including NASA, have created designs for vehicles capable of reaching nearby stars in a reasonable amount of time. The most notable are Project Daedalus and Project Longshot. Both of these designs make use of controlled nuclear explosions to propel the vehicle forward, and would be able to reach a neighboring star within 50 to 100 years.

The neatest thing about the nuclear rocket designs is that they are entirely serious. As far as I can tell, these things would actually work. Some of the relevant concepts have even been tested, with hilarious results. For example, in 1957 some American scientists accidentally launched a huge steel plate straight up into the air at six times escape velocity during a nuclear weapons test. The plate was never found.

I hope against all hope that we will send a probe to another star within my lifetime. More than anything, I would look forward to seeing the pictures that such a probe would take of another star system. Perhaps it would discover some new planets, and then send high-resolution photographs home. To me, that would be a dream come true.