Solar Sail - Any info?

[Vic]

Hey.
I realise this has little to do with airliners, but space travel is closely related to aviation, isnt it

Well, I was just looking at Rosaviakosmos' (Russian State Aeronautics and space agency) launch schedule and on May 27th they have this peculiar launch - Testing of a solar sail. I heard something about it on the news several months ago, this is why this caught my eye.

Apparently, its an experimental form of propulsion in space, it is supposed to particles coming from the sun to propel it. This is supposed to give it much more speed and save weight (due to the lack of conventional fuel). It is made by the "Lavochkin" design bureau with help from the US Planetary Society and the Russian Academy of Sciences.
The most peculiar thing is - this test "probe" which they are planning to launch will be launched from the Russian Nuclear Submarinal Cruiser (RNSC) "Karelia" or "Arkhangelsk", which just happen to be "Akula" or NATO: "Typhoon" class nuclear submarines which will be located in the Barent's Sea. Does anyone have ANY clue as to WHY they are launching a 100kg orbital craft from a submerged nuclear sub?
This ship is only a test probe, so it is fairly small - they are only going to test the sails themselves. In the future they plan to use a 600sq.m version on the "Soyuz" class ships.
All this information is from two articles I read on this topic and the news feature. Does anyone have any details on this thing? I think this is a pretty interesting project and would love to hear more about it!
This is the only article I found that was in english http://english.pravda.ru/science/19/94/379/15344_solar.html
Vic
P.S. There are alot of tiny meteorites in Earth's orbit - so what happens when one of these hits the sail?
So this is great when you are going AWAY from the Sun, lets say from Earth to Mars, but what about coming back? (Towards the Sun, say Mars to Earth)

[TacitBlue]

http://www.space.com/businesstechnology/technology/solar_sail_010227_wg.html

Ive been reading about this too, heres one of the articles.

[Woodlouse2002]

I got the idea that for this to work you would need absolutely massive sails. And even then accelaration would be slow. Not to mention the fact you can only go in one direction...

[Vic]

I got the idea that for this to work you would need absolutely massive sails. And even then accelaration would be slow. Not to mention the fact you can only go in one direction...

Yeah, in the article the lady at Lavochkin says that it starts going at 1mm/sec  ;D But then after a few days it goes 160,000km/h.
It isn't as heavy as carrying fuel and an engine though  :D
Also: I just found out that apparently they can somehow fly back in the other direction...I cannot elaborate on that though. Assuming it means zig-zaging? Something like yachts going into a headwind? Any ideas?

[TacitBlue]

Maybe they use rocket engines for the return trip only. It would still save tremendouse amounts of fuel.

[Woodlouse2002]

Somehow, the idea of beating back to earth isn't really the same as simply sailing a boat up wind...

[SilverFox441]

There is another technique using expendable concentric mirrors to allow for deceleration or return. Basically you drop the larger, outer ring and flip the inner ring over...light bouncing off the outer ring is focused on the inner and is now going the other way.

Very cool technology in any event...could make transit around the solar system a whole lot more practical.

[Vic]

There is another technique using expendable concentric mirrors to allow for deceleration or return. Basically you drop the larger, outer ring and flip the inner ring over...light bouncing off the outer ring is focused on the inner and is now going the other way.

Very cool technology in any event...could make transit around the solar system a whole lot more practical.

Cool! Thanks for the info.
Can you clear up the deceleration/return process - So do they eject the large sails? Or just fold them or whatever?
Thanks man!
Vic
P.S. Still, does anyone know why they are launching the thing from a Submerged sub in the Barent's Sea?

[TacitBlue]

In that artical I linked to, it says that its a lot cheaper to launch it from a sub. I dont know it the sub will be submerged at the time of launch, I kind of doubt it.

[Woodlouse2002]

I personally think it's a silly idea. I'm fine with sailing on water but if i'm in space i'd want something slightly more mechanical propelling me forward.

[Vic]

Its just that I've heard that they are launching from an Akula class sub (172m long - largest in the world) from the Barent's Sea - most likely the Karelia or the Archangel'sk since they are the only Akula's in the Northern Fleet. Well, to the point - If I'm not mistaken, these intercontinental ballistic missiles are only launched from underwater. I think it uses pressure to shoot it out of the water and then the rocket engine engages and it is off. Again, correct me if I am wrong, but the rocket engines damage the hull lining of the sub if it is at the surface. Atleast on the Akula's and the newer subs because the outer lining is rubberized.
If anyone has any knowledge about the American Los Angeles class subs - the Akula is similar so please share  ;D

Woody - I know that it seems a bit wacked, but think about it...no fuel/oxygen tank behind you that can explode, no engine that can fail causing you to die - just a harmless breeze of solar radiation blowing through your hair  ;D

Vic

[TacitBlue]

Hmmm, I hadnt thought about the rocket damaging the hull of the sub. But still, its cheaper, they already had an ICBM to modify*, the sub is right there instead of bringing the rocket to Khazakstan or the US or South America to launch.

* Okay maybe they didnt already have it, but it had to be cheaper than building from scratch.

[SilverFox441]

A quicky diagram to show how the concentric mirror technology would work:

You can see that there is much larger surface area involved in acceleration...you've got a bigger mirror. In deceleration mode you've released the outer ring and flipped your craft around.

The primary use would be for a laser-boosted lightail (why rely on the Sun after all). laser boosting offers many advantages:

Increased acceleration, greater reliablity, greater control...

[Woodlouse2002]

I still don't think it'll catch on somehow. Especially for manned missions. Afterall that sail is not going to be very durable. And steering could only be dodgy at best.

[SilverFox441]

Canvas sails aren't very durable...but they caught on just fine for a thousand years or more.

The true value of lightsails isn't in manned missions though...it's in unmanned flight. Cargo, scientific missions, etc...