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Solar Sail News and Upcoming JPL Missions
abkaiser writes "I had the opportunity to interview a supervisor at NASA's Jet Propulsion Laboratory. The JPL is putting together several missions utilizing solar sail technology. The interview and article detail where NASA and the JPL are in using solar sails for applications and research.You can read the article or skip ahead to the cool pictures of prototype and proposed solar sails. The article addresses NASA's JPL solar sail missions, but not other commercial or private projects like Cosmos 1."
Did you see the pic in that article? :-P
Look closely and you'll see a well drawn Astronaut!
I wonder if his kid took part in writing this article?
The Planetary Society gathered private funds to launch the first solar sail probe: Cosmos-1. It was basically a proof of concept. However, the Russian launch system failed. One part of me was disappointed that a great scientific test failed, but the other says, "that is what you get for outsourcing to low-wage countries". I suppose I should get used to it. For good or bad, "free" trade is not going away anytime soon.
Table-ized A.I.
At the tender age of 12 (some 29 years ago) I submitted a drawing of a space ship powered by sails as part of a school homework assignment. I got the idea after visiting a friends house and seeing a strange ornament displayed in their window. It was a glass dome and inside were 4 paddles mounted cross wise (horizontally) on a vertical support. One side of each paddle was black and the other white (or silver, its hard to remember now). On a nice sunny day the paddles would start to spin. I was so enchanted by this I never forgot it, and dreamed about flying through space on solar sales for years after. I never guessed that one day I might actually get to see it in action.
Always reminds me of the short story Sunjammer. It brings to mind the massive racing yachts. Ever since I read the story in my teens the slow motion image of the ships colliding has stuck in my mind. I'd love to see a solar sail race. The scale alone would be epic.
Or if there is a better way. I know NASA is all about research and pushing forward the boundaries of science. But I think they are spreading themselves out too thin. Especially if you consider how little money they get.
I have noticed that when I take on too many part time coding projects, I get none of them done right. I have a limit amount of personal coding time (maybe 1 day a week total) and working 1 hour on each of my projects doesn't get me very far on any of them. I do them all half-assed or never even complete them.
This is what I see happening with NASA.
On the other hand, I can get a lot done if I just focus on 2 projects or 3 at the most. Focus all my free coding time and energy on the 2 or 3 that I have time to do. This way I actually do a good job on the few things I do pursue, and I actually finish up on them.
I think this is what gave NASA its early successes. They focused and pushed in specific directions.. that and they had a lot more money back then.
I wonder if NASA would be better to slim down and focus on two or three goals and and drop everything else. Put it on their todo list, but not actually work on it, till higher priority goals are met. They have a severe shortage of resources, and they aren't the most efficient at using them (being a government agency after all), they could slim down and use all their resources to accomplish a smaller set of goals.. but actually ACCOMPLISH them.. not just probe around in different random directions. This scattered approach is not letting them devote enough resources to actually finish anything.. and the projects that do finish, end up taking so long that the public looses interest.
For instance, if NASA took on a task similar to putting a man on the moon. Say.. putting a man on mars.. or putting a base on the moon. Pick one, and dedicate all their research towards it. I think something like this would excite the public more, and perhaps even get more funding. The public isn't as impressed when NASA says "Oh we've been prodding around at these 20 different technologies that may one day be feasible and we could one day use but they are atleast 20 years away from being usable." But if NASA said "we have accomplished 4 of the 25 goals we have set for putting a base on the moon, we are working on 5 more goals and we are hoping to have them done by the end of this year. If everything goes as planned we should have a base on the moon in 10 more years, construction could start as soon as 3 years from now"
Now THAT sounds exciting!
- Tempestdata
Actually, solar sails are pushed by photons. The force generated on a solar sail by the solar wind (all of the "crud") is about an order of magnitude lower than that generated by photon momentum transfer. OTOH, the proposed Mini-Magnetospheric Plasma Propulsion (M2P2) system does use a "magnetic sail" of sorts to obtain thrust from the solar wind.
There is one big detail these amateur scientists have not accounted for : space is full of stars. For any photon coming from the sun, there are millions that come from the exact opposite direction. Why do you think it's dark outside ? because those photons anihilate electromagnetically against each other.
You would be correct if, when you looked outside, the sky were uniformly grey - there would be equal amounts of light of all colors coming from all directions, resulting in zero net solar pressure.
However, if one looks around in space, one will rapidly see that there is a WHOLE LOT more light coming from the sun than from any other direction. Aside from everyday experience, one can prove this just by recalling that there are shadows on the moon's surface caused by sunlight. If all the light from other stars was large in comparison to the light of the sun, the Moon's surface would appear (from Earth and Neil Armstrong's P.O.V.) almost uniformly grey.
As for why the sky is dark, it has nothing to do with the photons of other stars interfering with one another. It has to do with dust and the incomprehensibly vast distances between stars. The light from other stars appear as pinpricks of light because they are so far away. Stars that are really far produce weak light (recall light intensity decrease by 1/r^2 - or do you recall that, since you obviously know nothing about how physics and astronomy really work), and a lot of that light gets intercepted by dust long before it reaches our eyes.
So, in short, the myth that you speak of is itself a fallacy. There is a tangible and harnessable force from the solar wing.
Neil Murphy Dismisses the notion on a nonphyiscal solar sair right off hand. "We use aluminized plastics and nanotubes. You really do have to have a physical sail. Magnetic fields interact, but not in the same way." What about Robert?
Magnetic sails proposed by Robert Zubrin can be seen in the middle of this NASA page. So is it or is it not feasible?
Perhaps Mr Murphy has time invested in physical sail research...
Me? I just wanna be a fry cook on Venus.
One interesting thing about the physics of solar sails is that, counterintuitively, the worst possible thing to do with one is turn it perpendicular to the sun's rays. You actually get the maximum rate of transfer of kinetic energy if the sail is at 55 degrees to the rays, rather than 90 (explanation here, p. 149). There are also some pretty counterintuitive physical results about ordinary water sailing, e.g., that it's possible for some racing sailboats to complete a closed-loop course at an average speed greater than the speed of the wind!
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JPL never really had anything to do with jets as we know them today. My understanding is that when it was founded by some Caltech faculty and students in the 40's to do rocket research, "rocket" was kind of a dirty word due to lingering memories of German rockets in WWII. Rockets were also commonly called jets until the mid to late 40's. One of JPL's first successes was the development of JATO technology, which stands for "Jet-Assisted Take Off", even though it is really the use of rockets to help large planes take off on short runways.
JPL was transferred to NASA in the 50's and built Explorer I, the US's answer to Sputnik. Since then, JPL has been the prime NASA center for unmanned spacecraft, mostly sent beyond Earth orbit. Since most JPL missions travel pretty far into space, solar sails are a natural thing to be researching.
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