NASA Begins Planning For An Interstellar Mission In 2069 (nypost.com)

Long-time Slashdot reader cold fjord writes: During the 2017 Geophysical Union Conference, scientists from NASA's Jet Propulsion Laboratory revealed that they are planning an interstellar exploration mission for the year 2069. The goal is to send a probe to Alpha Centauri, some 4.3 light years away. NASA is working on technology to allow a spacecraft to reach 10% of the speed of light, which might allow them to reach Alpha Centauri in as soon as 44 years.

A number of technologies are being explored, although there are many practical hurdles. The New Scientist adds that the 2016 NASA budget directed NASA to study interstellar travel that could reach 10% of the speed of light by 2069.

Comments

Communications?

[HuskyDog]

Well one wishes them the best of luck, but it seems to me that going fast enough is only a tiny part of their problems and that getting any sort of useful communications back again is a least as big a challenge.

Consider the New Horizons mission to Pluto. The spacecraft is large and has a big high gain antenna. Also, it's power source hasn't been sitting around for 44 years. Never the less, data returns to earth at a few hundred bits per second.

Now consider Alpha Centauri. My quick calculations suggest that it is about 7000 times as far away (can someone confirm that?). Applying the inverse square law gives us a received power level - assuming the same transmit power and antennas - which is 77 dB (49000000 times) lower. Now, I am not saying that it can't be done, and I am sure that NASA have lots of very clever people, but as someone who has spend his career in radio and radar, finding an extra 77 dB is a very challenging requirement!

Re:Communications?

[HuskyDog]

Replying to my own post. A few more minutes though suggests that perhaps optical communications might work. I don't know very much about that technology, but preventing the receiving telescope from being blinded by the light from the star would clearly be a big issue to solve. Perhaps one could choose a wavelength where the star is relatively dark?

Aligning the transmitter sounds tricky, but presumably you could use the same optics to track the sun (which is presumably quite bright when viewed from Alpha Centauri).

Re:Donâ(TM)t. Be. That. Guy.

[K. S. Kyosuke]

It's spelled "you're" and "parties". And you have no idea.

That would be pretty useless

[Solandri]

The goal is to send a probe to Alpha Centauri, some 4.3 light years away. NASA is working on technology to allow a spacecraft to reach 10% of the speed of light, which might allow them to reach Alpha Centauri in as soon as 44 years.

First, warp drives do not exist (yet). You cannot instantly jump to 10% the speed of light and spend 44 years coasting to Alpha Centauri. To travel 4.3 light years with a constantly accelerating technology would require you to hit 20% the speed of light, not 10%. If you constantly accelerate up to 10% the speed of light by the time you reach the destination, then it'll take you 87 years to traverse 4.367 light years, not 44 years.

Second, you don't want to be accelerating the entire trip. Otherwise once you reach the destination, you're traveling way too fast for the trip to be of any use. Assuming the Alpha Centauri system is about the same size as our solar system, a probe reaching it at 20% the speed of light would pass through the entire system in a little over a day. It's stupid to travel 44 years just to have one day of science gathering. To be useful, you need to accelerate to the halfway point, the decelerate to the destination.

This means the trip of 44 years would require hitting 20% the speed of light by the halfway point - it would need twice the acceleration of a mission which hit 20% at the destination. So combined with the 10% vs 20% speed of light error, you actually need to develop a technology with 4x the acceleration of a mission which would arrive at Alpha Centuari at 10% the speed of light.