Outer Space Thread

[jim]

I wonder what that does to your back coming back. I probably feels like you are being crushed.

[JCShutout]

JPL Caltech made some awesome futuristic posters. Free to the public.

http://www.jpl.nasa.gov/visions-of-the-future/

Spoilered for size. (Only 3 random ones)

[SHOW]

[pioneer98]

Billionaire Yuri Milner is looking at sending a probe to Alpha Centauri that would arrive within "a generation". To get there that fast they are looking at building an extremely light probe that would weigh on the order of grams, and they would fire a massive laser at it from a mountain in Chile.

http://www.theatlantic.com/science/arch ... ri/477669/

Milner envisions a sail that’s only a few meters wide. Picture a thin disc about the size of a round picnic tabletop. It would have miniaturized electronics onboard, including a power source, cameras, photon thrusters for navigation, and a laser for communication. Some of this kit would be bundled into the disc’s center, and some would be distributed through the rest of the sail. But it would all be a single unit: If you saw it streaking by, it would look like a flat, round sheet of reflective material.

The laser team would need to time its daily blast carefully, to avoid destroying the satellites and planes that pass overhead. When fired, the beam would shoot up through the atmosphere, and slam into the disc-like probe, sending it hurtling toward the edge of the solar system. After only a few minutes, the probe would be traveling at a significant fraction of the speed of light. It would pass Mars in less than an hour. The next day, it would streak by Pluto. (New Horizons took 9 years to achieve this feat.) As the probe headed deeper into the Kuiper belt’s recesses, another one would pop out from the mothership, and float into the laser’s line of sight.

I asked Milner how an ethereal, nearly weightless spacecraft could withstand a blast from a mammoth laser. “You need to reflect 99.9 percent of the light or else it will evaporate,” he said. There are ways to protect the spacecraft from the beam, but it’s tough to do it without adding too much mass.

[go birds]

*sigh* more cool space [expletive] i probably wont see in my lifetime

[pioneer98]

The thing that article didn't talk about is that you'd have no way of slowing it down much. If it can get to Mars in less than an hour that would mean it would fly past planets really quickly to get much data once it got there. I guess it did say it would have tiny thrusters. They'd probably have to work pretty hard though to slow down from such an enormous speed.

At first I was worried about if the electronics would still function after 20 years in space. Then I remembered that traveling at that speed, time would move slower on the probe and it's "age" could be quite a bit less than 20 years. The article talked about dust and debris is the biggest problem and that's why they'd send a few hundred of these, hoping one would survive the whole trip.

If this laser is so powerful it could vaporize something, and you are aiming it at an object that will reflect 99.9% of the light, you have to be really careful where you point that mirror.

[jim]

If it takes an hour to get to Mars, and right now Mars is about 3x closer to us than the sun, and it takes light about 8 minutes to get here from the sun, then this object would be traveling somewhere around 8/240 = .03c. There is almost no time dilation at those speeds, so maybe the things clock would register 19.999999999 years instead of 20, but not enough to make a difference in the lifetime of the electronics. Even at 10 times that speed - .3c - you still wouldn't get enough time dilation to make much of a dent in the 20 years. At .9c you have around a factor of 2 reduction - so that ship's clock would be < 10 years.

Why would the electronics fail after 20 years?

[Arthur Dent]

Why would the electronics fail after 20 years?

They want to build a probe that weighs on the order of grams. What kind of power source weighing that little could maintain enough power to transmit a signal over the 4 light years back to Earth for that long?

Incidentally: Getting to Alpha Centauri in twenty years means averaging around 0.2 c (its still accelerating when passing Mars), though that is still too slow to have enough time dilation to make payloads have a significantly increased lifetime.

[Gashouse]

I thought the piece on NPR said today that it may take 20 years before this is ready to launch. I assume a big part of that is the time needed to finish inventing/developing the necessary components at the scale they need them to function.

[Arthur Dent]

Reading about this lead me to the 70s version: Project Daedalus. Apparently, we used to dream bigger:

[jim]

Why would the electronics fail after 20 years?

They want to build a probe that weighs on the order of grams. What kind of power source weighing that little could maintain enough power to transmit a signal over the 4 light years back to Earth for that long?

Incidentally: Getting to Alpha Centauri in twenty years means averaging around 0.2 c (its still accelerating when passing Mars), though that is still too slow to have enough time dilation to make payloads have a significantly increased lifetime.

Kryptonite would where I would start.

But yeah good point.