Solar Sail Simulations

A solar sail uses radiation pressure from sunlight as a means of propulsion.
It consists of a large mirrored sail to intercept and reflect the light,connected to a small spacecraft.
A small force is exerted perpendicular to the sail when light is reflected.
The contribution to this force by the solar wind is five thousand times smaller than the radiation pressure.
A solar sail has the potential to reach higher velocity than a rocket propelled spacecraft.
The journey time for a mission to our nearest star will be found by simulating some alternative maneuvers and spacecraft designs.
The total mass of the sail and spacecraft is 100 kilograms in every case.

We start with a sail size of 200 by 200 metres.
The simplest maneuver is a direct path from the Earth to the star.
The initial velocity of the spacecraft is set to 1.25 times the orbital velocity of the Earth.
The velocity after six months is 33 kilometers per second, which is barely maintaining its initial velocity.
Flight time to the nearest star is 36000 years.

Next we increase the sail size to 1000 by 1000 metres, and repeat the direct path to the star.
The short white line shows the orientation of the sail, and the yellow arrow shows the direction and magnitude of the force on the sail.
The velocity after six months is 168 kilometers per second. Flight time to the star is 7100 years.

An alternative maneuver is to do a close flyby of the Sun, making use of the greater light intensity.
The sail size is 200 by 200 metres, and the initial velocity of the spacecraft is set to 0.75 times the orbital velocity of the Earth.
The orientation of the sail can be controlled to increase or to decrease the orbital velocity of the spacecraft.
To approach the Sun the spacecraft must decrease its orbital velocity.
The sail is reoriented as the spacecraft passes the Sun, to increase the orbital velocity.
Closest approach is 20 solar radii, and the final velocity is 133 kilometers per second.

Next, another solar flyby maneuver but with a closer approach.
Onscreen are shown the flight day, the speed of the spacecraft in kilometers per second, the maximum acceleration in g's, the distance of the spacecraft from the Sun in solar radii, and the closest approach in solar radii.
Notice that the spacecraft velocity remains almost constant as it leaves the Sun.
The radiation pressure is balanced by the gravitational attraction.
Closest approach is 10 solar radii, and the final velocity is 190 kilometers per second.

An extremely close flyby may produce a still higher velocity, if the spacecraft survives.
Closest approach is 2 solar radii, and the final velocity is 441 kilometers per second.
Flight time to the star is 2700 years.

What is effect of increasing the sail size ?
We increase the sail size to 250 by 250 metres, and repeat the solar flyby maneuver.
The radiation pressure is too great and it is difficult for the larger sail to approach the Sun.

Perhaps a hybrid sail would be of advantage.
Here we use a sail size is 200 by 200 metres when approaching the Sun, and a sail size of 400 by 400 metres when leaving the Sun.
Maximum accelaration is about a third of a g.
Closest approach is 10 solar radii, and the final velocity is 368 kilometers per second.
Flight time to the nearest star is 3300 years.

Category:

Science & Technology

Tags:

• Solar
• Sail
• Simulation

[Sciagateist]

I read about "fast solar sailing" on wikipedia and they use a slightly different approach to the sun and that might be better.

[BrunoTheQuestionable]

Thanks for the reference. It looks like that trajectory would give a higher velocity approaching the Sun, which should be carried through to the final velocity. I think this calls for another simulation :)

[BrunoTheQuestionable]

I tried a simulation with a 200x200 sail, going out to about 2 AU before the Sun flyby, but the final velocity wasn't noticably better than a direct flyby :(

[BADAWYY]

Yes, but what if we make a solar sail with one kilometer square area and unpack it only near the Sun? What if after the initial gain in velocity we fire up some engines to add to the speed? What if once got out of the heliosphere that surrounds our solar sitem we encounter some parasite galactic currents that will either accelerate us further or stop us?

[BrunoTheQuestionable]

A simulation with an additional ion engine, fired at closest approach gave slower final velocity.

[sheepwshotguns]

no way!?

not bad for a sail boat.

[BrunoTheQuestionable]

Yeah, I'm amazed how big the radiation pressure is.

[SpazzyMcGee1337]

What if we provided some light of our own? A large laser could provide a lot more kick than the Sun. Or we could just use some solar mirrors to direct additional sunlight at the spaceship's sail. We could produce many times the acceleration we would get using just the Sun.

[America100000able]

You should have had done a 1,000x1,000 meter sail at the closest distance you could have brought it to the sun, and see what that would have done.

[Omega2064]

Did the calculations take into account that the sail should continue to gain velocity as it heads outwards from the sun?

[Arkanoid1212]

@Sciagateist use a propulsion beam

[sweetsongman1]

@docatomics gamma ray burst riding huh? think about that. gamma ray bursts are more powerful then you can imagine. ok il put it into perpective. imagine the death star's laser and multiply that by 30,000,000 and you got the power of an average gamma ray burst. that would completely pwn the sail like a red hot knife through butter

[sweetsongman1]

36,000 years hmm? yeah i think i can wait that long...boy i cant wait to see my greatgreatgreatgreatgreatgreat­greatgreatgreatgreatgreatgreat­greatgreatgreatgreatgreatgreat­greatgreatgreatgreatgreatgreat­greatgreatgreatgreatgreatgreat­greatgreatgreatgreat grandchildren :D

[yarahahrwe]

now do antimatter catalyzed orion rockets :p

[sunsunsunm00n]

日本の技術試験衛星 イカロスが此処まで出来たら凄いのにね

[docatomics]

...if only we could build strong enough to harness mass coronal ejection , and the knowledge to predict them, then we could carry a large supply of navigation fuel & payload. Perhaps some day we will harness more of the solar emissions including the plasma CME with a electromagnetic sail , not unlike that earth generates? This would also provide a fuel catchment for manoeuvring, might go between the stars, if jumping on nova wake, magnistar or even gamma ray burst power. IF ONLY there was will

[SpankBankLLC]

Yea it sounds like crap tech until you tell the correct way to use it. Sling shot the craft off venus as many times until you are going as fast as you want. Simply role off the sun and venus while collecting speed each pass.