You call that a PROBE?! - Project Daedalus was a 1970s design for what would still be our fastest way to the stars.
So there has been some talk and articles about possible planets around our nearest neighbor.
Stormbringer's thread on building a dedicated space telescope to stare at Alpha
got me thinking of what would even be possible to do if we somehow did find a habitable planet possibly with life next door.
Quick Alpha Centauri fact sheet for those who don't know:
- Alpha Centauri A and B (along with the smaller red dwarf Proxima Centauri) is the closest star system to Earth, at a mere 4.3-4.5 light years
(around 26.5 trillion miles).
Now how long would it take to send a unmanned probe
there with present and near-future technology which is well
* and doable within the next 50-100 years? I'll do the math so you don't have to.
By "well understood" I am ruling out things like Harold White's Alcubierre Warp Drive research.
NOTE: The speed of light equals 1.00c or 186,000 miles per second/669,600,000 miles per hour.
- At 0.10c (10% the speed of light or around 67,108,088 miles per hour) a small probe could reach it within 50 years. However, to build something that
fast is daunting (but NOT impossible) at present time.
Chemical rocket propulsion:
- The fastest chemical propulsion spacecraft we've ever designed, New Horizons which will reach Pluto this summer is travelling at 0.000054c (around
34,400 miles per hour - If it were pointed at Alpha Centauri it would take about 84,000 years to reach Alpha Centauri.
Ion drive propulsion:
- The fastest ion drive spacecraft we'e ever designed and launched on a long journey, NASA's Deep Space 1 probe got up to 0.000051c (around 34,100
miles per hour so it would be about the same amount of time to Alpha Centauri just slightly longer.
- NASA's Dawn Spacecraft could in theory exceed that if its ion thrusters (which are more efficient than those which are aboard Deep Space 1) had a
fuel supply to send it on a long constant journey in one direction. In theory it could get get up to 0.000089c (or about 60,000 mph) so it would
take around 50,370 years to reach Alpha Centauri.
Still a long time but our first big improvement technology wise between the Deep Space 1 launched in 1998 and Dawn which was launched in 2008
almost cutting travel time in half
- VASMIR ion drives could attain speeds of 0.000167c or 111,792 miles per hour. A trip to Alpha Centauri would take about 27,014 years.
- The fastest ion drive we've created (but not yet launched) is NASA’s Evolutionary Xenon
Thruster (NEXT) Ion Thruster
which ran for 5.5 years and achieved equivalent speeds of 0.00021 or 145,000 miles per hour in ground tests. -
If it were pointed at Alpha Centauri it would take about 21,440 years.
Both of these a long time but cutting travel time to around half of the previous 50,000 year figure.
- The fastest ion drive ever operated on any spacecraft was the PPS-1350 Hall Effect Thruster on the European Space Agency's SMART-1 probe which
attained 0.00002g acceleration which could in theory attain a speed of 0.00963c or 6,462,793 miles per hour if it were able to maintain constant
acceleration. - If so and it were pointed at Alpha Centauri it would take about 944 years to get there.
Nuclear fission propulsion:
is a proposed antimatter catalyzed nuclear pulse propulsion driven spacecraft propossal
designed by engineers in the 1990s at Penn State University. It would use antiproton clouds to trigger fission and fusion inside of fuel pellets. A
magnetic nozzle would funnel the force from the resulting explosions. It would be capable of reaching a cruising speed of 0.0032c or around 2,146,000
miles per hour. - A trip to Alpha Centauri would take about 1,400 years.
- NASA's Nuclear Electric (NERVA)
propulsion program was ended in 1972 but if properly developed a
spacecraft based on NERVA (1960s nuclear rocket technology) could achieve speeds of 0.05c or around 33,530,831 miles per hour - A trip to Alpha
Centauri would take around 90 years.
- Project Orion
- a proposed spacecraft which would detonate small nuclear
bombs behind a pusher plate would be able to attain a speed of around 0.033c or around 22,13,034,876 miles per hour. A trip to Alpha Centauri would
take around 137 years.
Of course for nuclear rockets to start flying would require off Earth mining and processing of nuclear materials and launch from space as there is
almost no nation who would want to take the environmental risk of launching a rocket full of plutonium from Earth even if studies show the risk is
low. Also international nuclear test ban treaties would have to be modified to allow the test and use of such propulsion systems again)
Nuclear fission/fusion hybrid propulsion
- Project Longshot
Developed by students at the US Naval Academy and NASA, from 1987 to 1988. Longshot was designed to be built at Space
Station Freedom the precursor to the existing International Space Station. Longshot was designed solely using existing 1980s technology although some
development would have been required. Fuel would be 264 tonnes of Helium-3/Deuterium pellet propellant. It would be able to attain a speed of around
0.045c or around 30,177,748 miles per hour - A trip to Alpha Centauri would take around 100 years.
Helium-3 is in abundance on the moon and we've found that comets like the one the ESA's Rosetta mission visited are rich in Deuterium so the fuel
could be mined by robotic spacecraft rather than lifted up from the Earth, effectively saving money and building space resource infrastructure at the
same time. Budget-wise this would probably require a massive co-ordinated international space program or a very ambitious USA spending on space in a
similar percentage of federal budget what it spends on one of the military branches.
Nuclear fusion propulsion:
- Project Daedalus
A study by the British Interplanetary Society between 1973 and 1978 to
design an interstellar probe spacecraft with technologies of the day or not too far fetched. The rules were that the designed had to use existing or
near-future technology and had to be able to reach its destination within a human lifetime. It would use fusion pulse (basically mini H-Bombs being
detonated in a confined space and the force funnelled out of the back). It would be able to attain cruise speed 0.12c or 80,473,995 miles per hour.
- A trip to Alpha Centauri would take about 38 years.
Now we're talking! Of course to achieve this would require MAJOR investment in the project, which by my estimate would cost between 50 billion to
develop the spacecraft, drive, fuel and launch and another 100 billion over the length of the 60-100 year project - so about 1 billion a year
following launch. Any takers?
edit on 30-3-2015 by JadeStar because: (no reason given)