Solar Sailing

[rdale]

    Solar sailing is a topic of growing technical and popular interest. Solar sail propulsion will make space exploration more affordable and offer access to destinations within (and beyond) the solar system that are currently beyond our technical reach. The lecture will describe solar sails, how they work, and what they will be used for in the exploration of space. It will include a discussion of current plans for solar sails and how advanced technology, such as nanotechnology, might enhance their performance. Much has been accomplished recently to make solar sail technology very close to becoming an engineering reality and it will soon be used by the world s space agencies in the exploration of the solar system and beyond. The first part of the lecture will summarize state-of-the-art space propulsion systems and technologies. Though these other technologies are the key to any deep space exploration by humans, robots, or both, solar-sail propulsion will make space exploration more affordable and offer access to distant and difficult destinations. The second part of the lecture will describe the fundamentals of space solar sail propulsion and will describe the near-, mid- and far-term missions that might use solar sails as a propulsion system. The third part of the lecture will describe solar sail technology and the construction of current and future sailcraft, including the work of both government and private space organizations.

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20090019561_2009016499.pdf (large file - 33MB)

[JulesVerneATV]

A Better Way to Turn Solar Sails

https://www.universetoday.com/articles/a-better-way-to-turn-solar-sails

[redneck]

One of the future accessories to solar sails will be beamed energy, probably laser. When leaving Earth or another planet, lasers assist the sail in gaining initial momentum. At the destination, lasers help deceleration from considerable distances. Consider Mars deceleration starting at millions of kilometers before the sail detaches to allow the craft proper to reenter. Detached sail rendezvous with an Earth bound payload that the laser helps accelerate out of Mars gravity field. Can start small and scale up as technology, politics, and need allows.

[edzieba]

A Better Way to Turn Solar Sails

https://www.universetoday.com/articles/a-better-way-to-turn-solar-sails

Use of LCD-based RDCs allows for varying the magnitude of the force vector, but not its direction. Other RCDs could allow vector pointing (e.g. CotS DMD arrays, or MEMS louvres).

[Tywin]

Deorbit sats too...


https://twitter.com/NanoAvionics/status/1930624398152609886

[Twark_Main]

A Better Way to Turn Solar Sails

https://www.universetoday.com/articles/a-better-way-to-turn-solar-sails

Use of LCD-based RDCs allows for varying the magnitude of the force vector, but not its direction. Other RCDs could allow vector pointing (e.g. CotS DMD arrays, or MEMS louvres).

True, but obviously you don't need to vary the force direction to steer a spacecraft. You can do it with multiple RCDs (effectively "differential thrust") or even just a single RCD if the sail is rotating. Spin rate can be controlled by having a pair of RCDs tilted at opposite angles.

[Vultur]

Deorbit sats too...

I think these drag sails are strictly speaking a different thing (though probably a related technology). At lower LEO altitudes, atmospheric drag is much greater than radiation pressure.

[Twark_Main]

Deorbit sats too...

I think these drag sails are strictly speaking a different thing (though probably a related technology). At lower LEO altitudes, atmospheric drag is much greater than radiation pressure.

Plus that drag sail looks like it deploys with rigid booms. Paradoxically that design can increase the collision probability, because now you have (say) 3x the catastrophic collision area but only half the orbital lifespan. Alternatives like Gossamer Orbit Lowering Device (GOLD) try to address this by making the entire drag device as a thin film, to minimize the breakup risk to the other object.

Solar sails don't have that problem fortunately, but they can still benefit from using lightweight inflatable tubes for rigidity.

[StraumliBlight]

Light sails are a promising method for traveling through space - indeed, Breakthrough Starshot proposed a laser driven version could reach nearby stars. But the exorbitant costs and engineering challenges of such a proposal have stymied its realization. What if there was a way of using the Sun - no lasers required - but keeping our dream of interstellar travel in tact? Introducing TARS.

[catdlr]

https://youtube.com/watch?v=MDM1COWJ2Hc

Light sails are a promising method for traveling through space - indeed, Breakthrough Starshot proposed a laser driven version could reach nearby stars. But the exorbitant costs and engineering challenges of such a proposal have stymied its realization. What if there was a way of using the Sun - no lasers required - but keeping our dream of interstellar travel in tact? Introducing TARS.

Also, isn't this concept similar to what Spin-Launch is doing, but in space, allowing for even greater distances and speeds? That said, you still need a counterweight on the other side to match and must be released at the same time in the opposite direction. Just make sure that the counterweighted projectile doesn't hit the Earth and cause the "Holdo maneuver."

[JulesVerneATV]

Foldable Solar Sails Could Help With Aerobraking and Atmospheric Reentry
https://www.universetoday.com/articles/foldable-solar-sails-could-help-with-aerobraking-and-atmospheric-reentry

[JulesVerneATV]

The Future of Propellantless Space Travel

https://www.universetoday.com/articles/the-future-of-propellantless-space-travel

[redneck]

The Future of Propellantless Space Travel

https://www.universetoday.com/articles/the-future-of-propellantless-space-travel

That's some of the possibilities. It misses a few. Lasers driving the sails. Pellet stream in various flavors. Momentum exchange with tethers and various mass driver/catcher scenarios. Other concepts somewhat further down the road.