French Firm Raises $2 Million To Sail On Sunlight (theguardian.com) 40
The French aerospace company Gama has raised 2 million euros to deploy a solar sail in space. The Guardian reports: Solar sails require no engines to move. Instead, they are pushed around by the pressure of sunlight. The angle of the sail determines the direction of motion. Gama plans to deploy a 73.3-sq-meter solar sail in a 550km-altitude orbit in October. It will be launched as an additional payload on a SpaceX rocket.
Gama hopes to demonstrate that solar sails can revolutionize access to deep space because they are cost-effective and scalable in size. After this year's deployment test, the company plans to launch a follow-up mission in 2024 to a higher orbit to demonstrate control and onboard navigation. In 2025, it hopes to emulate the Japanese and fly to Venus.
Gama hopes to demonstrate that solar sails can revolutionize access to deep space because they are cost-effective and scalable in size. After this year's deployment test, the company plans to launch a follow-up mission in 2024 to a higher orbit to demonstrate control and onboard navigation. In 2025, it hopes to emulate the Japanese and fly to Venus.
The Shredder (Score:2)
"Gama hopes to demonstrate that solar sails can revolutionize access to deep space..."
This sounds like an interesting idea, but I can't help but wonder about the tens of thousands of objects we are tracking in our own orbit that are moving at quite a destructive pace as compared to a rather target-sized sail.
I really hope we don't allow Greed to re-brand one of our orbits as "The Shredder". It's quite the inhibitor to our dreams of escaping this dying rock.
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Space debris is a big problem, but it's not one we can't solve. We are able to detect and track ever-smaller pieces of debris, and sooner or later we'll come up with a strategy for eliminating them. I still think it's basically going to have to be a distributed laser point tracking constellation, because of the enormity of the volume. What else can reach across such distances? Even if you could aim magnetism so far, most of the materials are non-ferrous anyway, and some of them are even non-metallic so rad
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Space debris is a big problem
Space debris is mainly a problem in earth orbit because of human-made junk.
Solar sails are designed for deep space beyond the earth's orbit, where debris is much less of a problem.
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Space debris is a big problem, but it's not one we can't solve. We are able to detect and track ever-smaller pieces of debris, and sooner or later we'll come up with a strategy for eliminating them.
Until you actually do solve it, it's a big fucking problem that has only gotten bigger in the last 30 years.
Nothing else even comes close to dismissing that fact.
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The big problem is that very few attempts have been made to solve it. Perhaps for fear of making things worse? But doing nothing isn't a viable plan either. The stuff not in LEO isn't just going to go away because we waited, at least not the bulk of it.
The Autocleaner (Score:2)
but I can't help but wonder about the tens of thousands of objects we are tracking in our own orbit that are moving at quite a destructive pace as compared to a rather target-sized sail.
Though in the specific case of this article's experiment, 500km seems to me (astronomy buffs, please correct me if I'm wrong*) low-altitude enough so that the "magical Autocleaning" effect of the thin drag still present in LEO is there and reduces the danger to the sail.
There's a reason why ISS and Hubble are in LEO: without an active boost, nothing stays long at this orbit to pose a long-term risk to the hardware.
There's a reason why also mega constellation (such as SpaceX' Starlink) put their satellites i
Use a solar sail to fly to Venus? (Score:2)
While the idea is possible. Wouldn't it be easier at first to go in the direction that light is pushing you.
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You learn more by doing harder things. Boat on water sailors have been moving against the wind for millennia - it is called tacking [wikipedia.org]
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You learn more by doing harder things. Boat on water sailors have been moving against the wind for millennia - it is called tacking [wikipedia.org]
And that works only because in sailing, the keel is used to push against water resulting in net force into the wind. No water or keels in space, sorry.
It is possible to use a solar sail to get to Venus, because, counter-intuitively, to get closer to Sun you don't need to thrust toward the Sun, but against the direction of your movement. This has exactly nothing in common with what sailors do.
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You may learn more by doing harder things, however it is often useful to get the fundamentals down first. You are not taught how to track as your first lesson in sailing. You need to first be able to learn how to catch the wind with your sails and go in a straight line.
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You are taught how to tack in the first lesson. If you weren't, how would you ever get back to the dock? Wait for the wind to change direction?
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Make no difference, eg Sailboats often go against the wind.
https://en.wikipedia.org/wiki/... [wikipedia.org]
Space keel ?!? (Score:5, Insightful)
eg Sailboats often go against the wind.
Yeah but what's the space equivalent of the keel?
A ship can go against the wind because the resulting force which comes from the effect of the wind against the sail and the water against the keel give a net force accelerating the ship forward.
But what would be the "spacekeel" that a spacecraft would use to accelerate while facing toward solarwinds? Some giant space elevator?
Though in practice, you don't need to accelerate to go from Earth to Venus. Quite the opposite: you're going to a lower orbit (relative to the sun) so according to orbital mecanics you would need to shed velocity.
Though in that direction you would probably call it a "solar (wind) brake" instead of a "solar sail".
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No keel, but solar sails and wind sails do not work at all the same way. Solar sails work by reflection [wikipedia.org]. (There must be a better citation for that fact than that article, but at least they mention it.) It's not just the arrival of the photon, it is also its departure. So it's still not tacking, but you can achieve greater angles (to say nothing of thrust) than if the sail were all absorption (plus then it would have to dissipate the heat.)
This looked neat, https://ntrs.nasa.gov/api/cita... [nasa.gov]
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Yes and no. Besides reflection, the sail also responds to the solar wind which consists of particles which can stick to or bounce off the sail.
I forget the specifics but IIRC the solar wind always gives thrust perpendicular to the Sun/star whereas lights thrust can vary by tilting the sail.
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Yes, but the solar wind provides something like 1/10 of the thrust of the reflected photons.
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OK, didn't realize there was that much difference, just remembered reading somewhere that it had to be considered
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eg Sailboats often go against the wind.
Yeah but what's the space equivalent of the keel?
Gravity.
(usually of the sun)
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Or the magnetic field, usually of the Sun but maybe the Earth when in orbit.
Lose orbital velocity (Score:2)
To nitpick stuff:
To go from Earth to Venus (i.e. a lower orbit), a spacecraft would need to shed orbital velocity.
So yes it would work, except in that direction it would make more sense to call the contraption a "solar break" instead of a "solar sail".
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Maybe you meant "brake".
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"solar break"
Maybe you meant "brake".
YSe! Exatcly taht.!
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https://en.wikipedia.org/wiki/... [wikipedia.org]
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While the idea is possible. Wouldn't it be easier at first to go in the direction that light is pushing you.
The actual rocket scientist Robert L Forward wrote a number of SciFi novels one of which is called Rocheworld and contains excellent descriptions of using solar sails and since he had at least one patent on them he can be assumed to know what he was talking about. So give it a read, as I recall it had an excellent appendix with drawings about the systems involved.
French firm (Score:2)
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I'm not sure if you're being racist or just plain stupid.
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I don't have a dog in this very stupid fight but nothing is a race, there is no scientific basis for same, so the answer is no but it is always no. However, that is irrelevant to racism, because it's based on the belief that race exists and is relevant, and people who think those things can easily believe that French (or whatever) is a race.
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Old is new again (Score:2)
They might talk to the James Web team. I'm really interested as a concept to see one of these working. Especially slowing when nearing arrival. Probably not going to revolutionize anything though.
Space Origami!
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I'm really interested as a concept to see one of these working. Especially slowing when nearing arrival. Probably not going to revolutionize anything though.
Then go back in time to 2010 and look at Japan's project Ikaros.
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I'm really interested as a concept to see one of these working. Especially slowing when nearing arrival. Probably not going to revolutionize anything though.
Then go back in time to 2010 and look at Japan's project Ikaros.
Yeah, it worked within what they were trying to do. A bit of thrust, and a bit of attitude control. Rather than a flyby, what would have been interesting is how they would enter orbit around Venus.
Now it is possible they can creep up on something very slowly to be captured to orbit. Dayum, that's life in the slowest lane. But I suspect for most practical matters of going some place and entering orbit, it will need to be a hybrid sail and thruster system, relying a lot on rockets to escape Earth's gravity
Will it have a wire basket in front? (Score:2)
Been done ... and still doesn't work. (Score:2)
Read this New Scientist article [newscientist.com] written in 2003.
Then realize that there have also been several attempts to prove solar sails work and none have been successful. The proof is kind of like the debate about 'Big Foot' ie. there would have been definitive, incontrovertible evidence by now and you would have heard about it.
Modern snake oil :-)
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>Then realize that there have also been several attempts to prove solar sails work and none have been successful.
Project IKAROS would like a word:
https://en.wikipedia.org/wiki/... [wikipedia.org]
It used a solar sail and went to Venus with it. That was 2010, so a while after your 2003 article.
Re:Been done ... and still doesn't work. (Score:4, Informative)
None have been successful?
Cosmos 1 [wikipedia.org]: launch rocket failure
SSSat1 [skyrocket.de]: sail opening failure
NanoSail-D [wikipedia.org]: launch rocket failure
Not a lot of actual 'failed to sail' in the failures list. These failures, however, are more than balanced by actual successful demonstration missions and actual production mission use of solar pressure:
SSSat2 [skyrocket.de]: successful demonstration of low orbit attitude control
MESSENGER [wikipedia.org]: skipped some thruster firings for course adjustments as it instead used solar pressure
Hayabusa2 [issfd.org]: replaced attitude control functionality of failed reaction wheels with solar radiation pressure
IKAROS [wikipedia.org]: demonstrated solar photonic acceleration on a trip to Venus
NanoSail-D2 [wikipedia.org]: test of using a sail for deorbiting
Lightsail 2 [wikipedia.org]: successful test to raise orbit via a sail
Attitude control in both orbit and deep space. Deorbiting and raising orbits. Acceleration in interplanetary flight. Green checkmarks in all these areas.
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There were two attempts.
Both successful.
How would a simple physical principle not be successful?
Like the Planetary Society? (Score:2)
They did several.
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