Aerographite Solar Sails for 2% of Lightspeed Just From Launch Near the Sun

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Matloff and Joseph Meany conceptualize a large solar sail made of aerographite which would only use the Sun to power a long term interstellar mission. It is based on an inflatable, hollow-body sail. This is updating concepts that goes back at least to the 1980s. Matloff and Meany set up an aerographite-graphene variant using a 90% absorptive and 10% reflective layer of aerographite that effectively pushes against the Sun-facing surface of graphene.

The radius of the sail is 764 kilometers, with the sail massing 5490 tons. The as yet unpublished paper has the payload mass 25600 tons. This is a much larger hollow-body sail than one made only of graphene. Matloff chose the mission to pass within 0.1 AU in order to hold down the g forces for the human crew.

An interstellar spaceship ark could carry a crew of hundreds to Alpha Centauri in about 1375 years. This is obviously a long time but the thought experiment is that with less than 5500 tons of new Aerographite material which has been made in some small quantities and just using the Sun the mission is possible.

If we could develop the life support systems and space habitats to enable sustainable independent living in space for hundreds then a series of colonies could be distributed around the solar system and beyond the solar system.

Nuclear energy would be needed for the sustainable colony because going far from the Sun would mean no usable solar power. Super green houses would be needed. A rotating habitat would be used.

If we expanded throughout the solar system and created an economy over 100 times larger than today, then the production of billions of tons of solar sails and space habitats would be viable. The world economy has grown by over 100 times from 1870 to today.

In this situation, I would envision hundreds of thousands of long duration space bases made every year to spread out around and from the solar system.

Aerographite is a synthetic carbon-based foam with a density of 0.18 kg per cuic meter. It is 15 000 times more lightweight than aluminum. It is a versatile material for highly efficient propulsion with sunlight. Release of an aerographite hollow sphere, whose shell is 1 micron thick, at 0.04 AU (the closest approach of the Parker Solar Probe) results in an escape speed of nearly 6900 km per second and 185 yr of travel to the distance of our nearest star, Proxima Centauri.

3 thoughts on “Aerographite Solar Sails for 2% of Lightspeed Just From Launch Near the Sun”

  1. The numbers ( I did ’em from scratch, yay ) kind of work out. But they also expose that the authors are employing a fairly LARGE amount of Magic in their work. Magic from the point of view of having tens of thousands of square KILOmeters of gossamer-thin (no, thinner even than that) film suspended in open space in such a way so as to garner Sols acceleration power and still somehow convey all those kilonewtons to a big ol’ honking spacecraft full of people, plants, pets, engines-of-survival for what, 1,300 years?

    Meanwhile, we’ven’t yet lofted so much as a kilogram of any of the constituents to space to test out the tethers-and-film idea. Or for that matter, even made the proposed stuff in any quantity larger than a few square centimeters.

    Magic.

    Working with numbers that include tethers (2,600,000 of them, to distribute the payload mass retarding force onto the sailcloth), setting the payload mass to 25,000 kg (which seems awfully small to last a millennium), my calculations come in along the same lines.

    Ultimate velocity of about 0.45% of ‘c’, time to α-Centauri of 890 years. Sail diameter of 275 kilometers. Might as well ‘wad it up’ (folded neatly, of course) after use, and install at the front of the arkship. To act as a pretty good interstellar dust catcher. Lousy for rocks.

    Or, being carbon, ‘burn it’ to CO₂ to feed the plants on board. For food. Carbon comes in handy over a 1,000 year cruise time.

    I’d sure like to see the experiments leading up to the proposed thought-experiment ship.

    ⋅-⋅-⋅ Just saying, ⋅-⋅-⋅
    ⋅-=≡ GoatGuy ✓ ≡=-⋅

  2. Before sending worldships to Proxima, there will be thousands upon thousands of light sails sent using the Sun’s light and lasers. From the 1 gram snowflakes to multi kilogram masses with kilometer wide sails.

    And some of them will even brake at their destinations with useful payloads, bringing machinery and instruments to study them in detail way before humans get there.

    I expect the progression of payload following a similar S-curve to other tech, just a little bit longer, once the technology is perfected. Eventually the threshold of sending autonomous fleets of robotic builders will be crossed, and they could start mining and building more of themselves and even colonies.

    In that way, planning for the starship braking won’t be necessary: just accelerate as much as you can here to reduce the trip duration, and ensure you built a laser array on Proxima to stop you.

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