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#1 2024-12-28 14:37:06
Key advance in solar sails for searching for interstellar life.
The Parker Solar Probe recently survived its closest flyby of the Sun at only 0.04 AU.
This gives confidence that the proposal to achieve high speed of a solar sail using a close flyby of the Sun using the ultralight, but high temperature material aerographite can work:
Interstellar Sails: A New Analysis of Aerographite
by Paul Gilster | Sep 27, 2023 | Sail Concepts |
https://www.centauri-dreams.org/2023/09 … rographite
Such a solar sail could reach a speed of 2%c, 6,000 km/s, using this close flyby. At this speed it could reach the solar gravitational lens(SGL) at 550 AU in only 6 months, and ‘Oumuamua in only 11 days(!)
The implications are stunning. Aerographite is an existing material. Then this means we currently have this capability.
Telescopes placed at the solar gravitational lens(SGL) would have the ability to amplify the images of an Earth-sized exoplanet by 100 billion times. It could resolve continent-sized features on such a planet.
‘Oumuamua is an interstellar object whose unusual motions led some to speculate it could be of artifical origin.
Then we now have the capability to directly observe Earth-sized exoplanets in other star systems and to determine features on an interstellar object that came into our solar system which may have been artificially produced.
Bob Clark
Old Space rule of acquisition (with a nod to Star Trek - the Next Generation):
“Anything worth doing is worth doing for a billion dollars.”
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#2 2024-12-28 15:01:58
- tahanson43206
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- Registered: 2018-04-27
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Re: Key advance in solar sails for searching for interstellar life.
This post is reserved for an index to posts that may be contributed by NewMars members over time.
This is a most promising topic, so I hope it does well here.
The idea needs to be developed into a proposal for funding.
A probe to take advantage of this capability would require a lot of work to set in motion, but the idea of catching up with our interstellar visitor might just have the interest value to earn funding from private sources.
In case of a probe to the solar lens site, there needs to be a way to slow down when the probe reaches the site. An ordinary ion drive might be able to perform that service.
Update: The power of solar radiation for delivering thrust on a surface must have been taken into account by the mission planners for the Parker probe. The calculations would have needed to take that force into account to be able to plan the series of closer and closer approaches to the Sun that are (apparently) planned. I hope that an enterprising member of the NewMars forum can/will write to NASA/JPL to ask about that aspect of flight planning.
Solar radiation pressure on deep space probes is highly likely to have been taken into account by mission planners working on flights near the Sun, such as Magellan to Mercury. I have a copy of James Miller's book on space navigation, and will try to schedule time to see if he mentions that factor. I **do** recall that thrust caused by out-gassing from materials used to make a spacecraft had to be taken into account when a particular mission flew on a path slightly different from the one planned. That would be a small thrust, but on a Solar System scale flight, it has to be taken into account.
Follow up:
Interstellar Sails: A New Analysis of Aerographite
by Paul Gilster | Sep 27, 2023 | Sail Concepts | 12 comments
This article (linked by Oldfart1939 in Post #1) contains plenty of forward looking ideas. One I noted was the use of starlight to slow a probe after it reaches a destination star in a couple of centuries. I like that idea as a significant improvement over the traditional fly-by concept I've seen previously.
The article by Gilster makes the point that the material absorbs photons rather than reflects them. This leads to heating of the material, but apparently never exceeding the melting point of the material. I assume there must be radiation to space going on at the same time as heating is occurring, but if that was mentioned in the article I missed it. The rate of loss of thermal energy to space would (or may) account for the survivability of the material when subjected to solar radiation near a star.
(th)
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#3 2025-01-05 11:10:25
Re: Key advance in solar sails for searching for interstellar life.
For slowing down it might be Robert L Forwards idea of reflecting back the light from the main sail to a smaller sail would allow you to slow down the smaller sail to stop at the destination.
A problem though is Dr. Forward intended this for the case of laser propulsion where the reflected light could be focused onto the receiving sail. This might not work for the non coherent light from the Sun.
However, actually for the solar gravitational lens case it still works as long as you are on a line extending out from the SGL so you may not need to slow down for that case.
In that Robert L. Forward conception of using reflected light from the main sail to slow down a smaller sail at the destination, he also included the possibility of using the same method to actually *return* from the far destination. Imagine getting returned samples from ‘Oumuamua, the Jovian and Saturnian moons, and Pluto!
However, there is that sticking point in using this method in the case we’re considering here. Forward was imagining it for laser propelled propulsion. In that case you can focus the reflected light that is coherent and collimated. But for our scenario we’re using solar light which will be non coherent and uncollimated. It may not be possible to get the highly focused light at long distances in this scenario. It might be we can carry a laser to do it but that may be too heavy. There may be other light weight methods to do it.
An intriguing possibility: IF it did work, then could it be used to do staging by sending focused light from the main sail *forward* to a smaller sail ahead of it? Then we could increase the speed multiple times by doing multiple staging.
Bob Clark
Old Space rule of acquisition (with a nod to Star Trek - the Next Generation):
“Anything worth doing is worth doing for a billion dollars.”
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