Follow Slashdot blog updates by subscribing to our blog RSS feed

 



Forgot your password?
typodupeerror
×

Comment Re:Hear Hear! (Score 2) 397

Ah, Americans and their "mammoth snowstorms" - try living on a rock in the middle of the North Atlantic. You know what we call a snowstorm with gale-force winds and copious precipitation? Tuesday ;) Our last one was... let's see, all weekend. The northwest gets hit by another gale-force storm tomorrow. The southeast is predicted to get hurricane-force winds on Thursday morning.

Here's what the job of someone dispatched to maintain antennae for air traffic control services has to deal with here. ;) (those are guy wires)

Comment Re:Visible from Earth? (Score 1) 126

A sun-like star is about 1 1/2 million kilometers in diameter. To blot out all light from such a star that's 10 light years away, a 0,75 kilometer diameter disc could be no more than 1/200.000th of a light year, or around 50 million kilometers (1/3rd the distance between the earth and the sun).

The brightest star in the sky is Sirius A. It has a diameter of 2,4 million km and a distance of 8.6 light years. This means your shade could be no more than 25 million kilometers away.

The sun and the moon both take up about the same amount of arc in the night sky so would be about equally difficult to block; let's go with the sun for a nice supervillian-ish approach. 1,4m km diameter, 150m km distance means it'd be able to block the sun at 800km away. Such an object could probably be kept in a stable orbit at half that altitude, so yeah, you could most definitely block out stars with the thing - including our sun!

Comment Re:keeping station behind it? (Score 1) 126

It makes sense. We can radiate individual photons for thrust if so desired. We can move individual electrons from one position in a spacecraft to another for tiny adjustments of angle and position if so desired. It seems you're going to be much more limited by your ability to precisely track your target than by your ability to make fine adjustments.

I think a much bigger problem is going to be isolating standing waves from within the shielding material from distorting its perfect rim (with a shield that big and thin, there *will* be oscillations from even the slightest thrust inputs). You need to isolate the rim from the shielding. And you also need to make sure that you can have a rim that can be coiled up for launch but uncoil to such perfection in space.

Tough task... but technically, it should be possible.

Comment Re:No (Score 3, Insightful) 126

I would presume that the bulk material in the inside has no need for accuracy, only the very rim. The question is more of whether you can have a coiled material that when uncoiled (deployment) can return to a shape with that level of accuracy. I would think it possible, but I really don't know.

I would forsee a super-precise rim with just a small bit of light shielding on its inside, deployed via uncoiling, and then attached to a much stronger, less precise uncoiled ring to which the bulk shielding material (and stationkeeping ion thrusters) are attached. The attachment between the two would need to provide for vibration and tension isolation (even the slowest adjustments in angle of such a huge, thin shield are going to set in motion relevant vibrations, you've got almost no damping - you want the structural ring to deal with those and not transfer them through to the precision ring). Not to mention that your shield will be acting as a solar sail whether you like it or not (unless you're at L2... but then your craft better be nuclear powered).

Your telescope behind it is going to need to do some real precision stationkeeping (either extreme precision on the whole spacecraft positioning, or merely "good" positioning of the whole spacecraft plus extreme precision adjustment of the optics within) . This means long development times and costs to demonstrate that you can pull it off before you actually build the shield. But I would think that also possible - just very difficult. If they take the latter route they could probably demonstrate that here on Earth, which would be a big cost-saver.

Slashdot Top Deals

This file will self-destruct in five minutes.

Working...