No, because the solar wind drops off around 100 AU, and the power of the solar wind is going to reduce the farther out you are. These kinds of craft would get much more acceleration from a laser array that can put much more concentrated energy into the sail. But just like the solar wind, it will lose power the farther away from the array it is, along with any kind of intermediary debris attenuating the beam or unfavorable angles between the array and the craft.
So you can get these to an appreciable fraction of the speed of light, but I don’t think we’d be able to get anywhere close to c with this kind of a setup.
Doesn’t “solar wind” refer to the physical particles emitted from the sun? Like hydrogen, helium, etc ejected from the sun’s outer layers?
My understanding is that the solar sail is propelled mostly by the photons themselves, not the atomic particles that may also be reaching it.
Of course this probably doesn’t change your argument at all, since the intensity of light drops off precipitously as you fly further and further from the sun.
What’s fun about these is that the mass of the actual vehicle can be much smaller if it doesn’t need to carry rocketry and fuel on board. So even though they’ll never compete with rockets for power (energy used over a specific length of time), starting at a lighter weight and never running out of fuel means that these systems could theoretically exceed the top speeds (relative to the earth) of our fastest rockets, given enough time.
Since these craft would be small, they wouldn’t have the power to transmit back to Earth anyway. So with something like this, you would actually want a string of these kind of crafts that you would propel along the same vector so that they could send the data back using each following craft as the next point in the network back to Earth. So each one can take additional pictures to get a resolvable image at the end!
Now, getting them on the same vector is the hard part, since we’re constantly moving through space and won’t have the same launch conditions on subsequent launches, but this is all theoretical at this point anyway.
There’s a paper from 1984 that worked out the math for a two-sail system that could get a spacecraft to Alpha Centauri, and slow down and end up in that gravity well, with a 41-year mission time. It would do so by discarding a reflector that points backward at the actual payload with its own sail. The paper also proposes a mechanism for a round trip mission, too, using 3 sails.
I hope it can be sent somewhere neat once they are done testing. But I assume it’s not configured for long range communication.
It would be cool if it could be sent, slowly, to a “nearby” body.
Iirc, solar sail designs like this can actually go stupid fast when properly propelled by something like a laser array.
Won’t the sail approach the speed of light if it stays on course in line with the sun for an exceptionally long time?
No, because the solar wind drops off around 100 AU, and the power of the solar wind is going to reduce the farther out you are. These kinds of craft would get much more acceleration from a laser array that can put much more concentrated energy into the sail. But just like the solar wind, it will lose power the farther away from the array it is, along with any kind of intermediary debris attenuating the beam or unfavorable angles between the array and the craft.
So you can get these to an appreciable fraction of the speed of light, but I don’t think we’d be able to get anywhere close to c with this kind of a setup.
Doesn’t “solar wind” refer to the physical particles emitted from the sun? Like hydrogen, helium, etc ejected from the sun’s outer layers?
My understanding is that the solar sail is propelled mostly by the photons themselves, not the atomic particles that may also be reaching it.
Of course this probably doesn’t change your argument at all, since the intensity of light drops off precipitously as you fly further and further from the sun.
What’s fun about these is that the mass of the actual vehicle can be much smaller if it doesn’t need to carry rocketry and fuel on board. So even though they’ll never compete with rockets for power (energy used over a specific length of time), starting at a lighter weight and never running out of fuel means that these systems could theoretically exceed the top speeds (relative to the earth) of our fastest rockets, given enough time.
How do they slow down or stop; is it by reversing the sail?
Just to zoom by the target in 100000 years so quickly no pictures or data can be captured.
That’s actually not that big of a deal!
Since these craft would be small, they wouldn’t have the power to transmit back to Earth anyway. So with something like this, you would actually want a string of these kind of crafts that you would propel along the same vector so that they could send the data back using each following craft as the next point in the network back to Earth. So each one can take additional pictures to get a resolvable image at the end!
Now, getting them on the same vector is the hard part, since we’re constantly moving through space and won’t have the same launch conditions on subsequent launches, but this is all theoretical at this point anyway.
There’s a paper from 1984 that worked out the math for a two-sail system that could get a spacecraft to Alpha Centauri, and slow down and end up in that gravity well, with a 41-year mission time. It would do so by discarding a reflector that points backward at the actual payload with its own sail. The paper also proposes a mechanism for a round trip mission, too, using 3 sails.