NASA Set To Launch Solar NanoSail Into Space

An anonymous reader writes "Earlier this year the Japanese space agency successfully deployed and used a solar sail to propel its spacecraft Ikaros, and now NASA announced plans this week for its own solar sail mission. This fall it will launch the NanoSail-D into orbit 400 miles up with a Minotaur IV rocket. Once deployed, it will orbit for 17 weeks, proving the technology and allowing astronomers to snap lots of photos."

Re:The Apollo crews would be ashamed.

[MichaelSmith]

NASA built the worlds first solar sails [wikipedia.org] anyway.

"D"

[nomad-9]

And here's the answer to the question everyone wants answered: What does "D" stand for?
"We chose the 'D' in the name, not because it came after models A, B, and C, but because it can stand for demonstrate, deploy, drag, and/or de-orbit."
- Edward "Sandy" Montgomery. NASA's Marshall Space Flight Center.

Re:Screw the solar

[strack]

you fail to recognise the very important fact that solar sails do not use reaction mass, so theres no fuel tank to run empty, so a solar sail will have thrust, and control over its own trajectory, for as long as the sun shines. and that, my good sir, is a very long time.

NanoSail? What's so nano?

[c0lo]

Before reading TFA, an amusing idea of NASA sending a sail just 1 nm wide crossed my mind. After the can't be reaction, I though they are going to use nanometer thick sails, and wondered what they are made of? Graphene sheets maybe?

Turned out that is not:

NanoSail-D has a surface area of more than 100 square feet and is made of CP1, a polymer no thicker than single-ply tissue paper.

Rrright... It's like... say... an ISP providing a "broadband package" with speed no lower than 56 kbps.

Unless it is a helluva-lot thinner than a tissue paper, what's so Nano in this sail?

Re:Screw the solar

[MichaelSmith]

I believe the USSR got some into operation.

Yep [wikipedia.org]

Re:The Apollo crews would be ashamed.

[Geoffrey.landis]

Wrong Wikipedia link, he should have shown http://en.wikipedia.org/wiki/Solar_sail#Solar_pressure_demonstrated_for_attitude_control [wikipedia.org]

Solar sailing was used for spacecraft attitude control on the Mariner ten [nasa.gov] mission to Venus and Mercury

Re:Proving technology that already works?

[Geoffrey.landis]

Nanosail D was originally to launch on one of the ill-fated Falcon 1 test flights, at which time it would have indeed been proving the technology. But now that JAXA have not only proved the technology, but applied it to interplanetary travel, it seems a bit moot.

Not at all. If you don't want to actually use technology in space, but just want to get points for saying "I flew the first one," then one flight is fine. If you're actually going to use technology, though, a first demo flight is just the beginning of the development and testing stage, not the end. Pretty much everything about Nanosail D is mechanically and structurally different from the IKAROS sail; in terms of physics, they are similar, but in terms of technology, they are very different. IKAROS is held out by spin, for example; this makes for a solar sail that is not very maneuverable. Nanosail is strut stabilized, this is a sail that can be redirected much more easily (for example, to use for orbit-raising).

They are also not merely different technologies, they are very different mission types-- Nanosail-D is (as its name implies) a demo of a very small sail. Some applications are there for small sails; some are there for medium sails, and there are also a lot of applications for huge sails-- kilometers and larger, which still have to be demonstrated. Saying "we launched one sail once, now the technology is fully developed at all sizes and for all missions" is just ignoring the real world of technology, where every step needs developing and testing.

Finally, the IKAROS sail doesn't demonstrate very low specific mass, which is the key to practical propulsion. Nanosail-D is about three times better.

Saying "a solar sail flew once, so the technology is developed and it's moot to launch another one" is about as accurate a comment as saying "A horseless carriage was tested in 1801 so the technology is demonstrated and it's moot to demonstrate a different one."

Micrometeoroids- not a problem [Re:bad idea]

[Geoffrey.landis]

Hmm, a gian, thin space sail that's probably several square miles. Boy, I sure hope one single little chunk of orbital debris or meteor doesn't impact that gigantic area in the 2 weeks or it won't work so well. Sails tend to not like meteors impacting them. Too bad the odds of that happening are about 99.99999%. I don't know what they're thinking.

Actually, solar sails are almost completely unaffected by small impacts by micrometeoroids or debris. The micrometeoroids go right through. They do leave a hole, which reduces the area of the sail by a trivial amount, but sail areas are so large, and micrometeoroids so small, that it would take decades to centuries before the effective area loss reduces performance significantly.

If a micrometeoroid impacts the struts or support structure, of course, that may be more of a problem, depending on how redundant the structure is (and how big the impact-- but micrometeoroids are small, and debris is not much of a problem in interplanetary space, where sails are most likely to be used). Of course to make a sail lightweight, the support structures had better account for only an extremely small fraction of the sail area.