Solarsail

star_sirius · Apr 1, 2005

The wait is over in 1 or 2 months! <div class="Discussion_UserSignature"> A dazzling bluish luminosity from A distant south pacific. <img id="cb51e87e-8221-424c-8ff2-78c95122196c" src="http://sitelife.livescience.com/ver1.0/Content/images/store/11/15/cb51e87e-8221-424c-8ff2-78c95122196c.Large.jpg" alt="blog post photo" /> </div>

CalliArcale · Apr 1, 2005

Woohoo! I hope this launch goes off well; the prototype was lost due to a failure in the Volna booster. It would be a thrill to see this technique, so popular in science fiction, become a reality. <div class="Discussion_UserSignature"> "People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff." -- The Tenth Doctor, "Blink" </div>

holmec · Apr 1, 2005

Wooh, which one is launching? Comos1 or other? <div class="Discussion_UserSignature"> "SCE to AUX" - John Aaron, curiosity pays off </div>

holmec · Apr 1, 2005

I guess it is Cosmos1, they have a launch date for April 30th. http://www.planetarysociety.org/solarsail/index.html <div class="Discussion_UserSignature"> "SCE to AUX" - John Aaron, curiosity pays off </div>

star_sirius · Apr 29, 2005

No matter how advance spaceflights mankind will develop within solar system, even do a full conversion from type 0 to type I civilization, there is nothing cooler than Solar Sail, we are talking about a spacecraft without an engine - it is pushed along directly by light particles from the Sun, reflecting off giant mirror-like sails. Because it carries no fuel and keeps accelerating over almost unlimited distances, it is the only technology now in existence that can one day take us to the stars. The Launch Date: May 31, 2005. That's about 32 days and few hours left. Woohoo! http://www.solarsail.org/ <div class="Discussion_UserSignature"> A dazzling bluish luminosity from A distant south pacific. <img id="cb51e87e-8221-424c-8ff2-78c95122196c" src="http://sitelife.livescience.com/ver1.0/Content/images/store/11/15/cb51e87e-8221-424c-8ff2-78c95122196c.Large.jpg" alt="blog post photo" /> </div>

star_sirius · Apr 30, 2005

This solar sail thing is not for people in a hurry, i heard even the launch itself may take few days, it has to be launched from a russian's nuclear submarine, once it unfolds its eight triangular vanes, ground controllers will tilt the vanes like a remote airplane, then a slight boost to the spacecraft's orbit. The beauty of it is the speed, unlike conventional spacecrafts, they can continuously accelerating as long as the Sun is shinning. Wow! After 100 days , the solar sail would be moving at incredible 16,000km/h, the velocity will increase 10 times in 3 years, three times faster than Voyager, my question is at this speed, how stable the vanes are, will the vanes twist and curl themselves...please don't sound wheezing ..i hope at least not in space. <img src="/images/icons/wink.gif" /> <div class="Discussion_UserSignature"> A dazzling bluish luminosity from A distant south pacific. <img id="cb51e87e-8221-424c-8ff2-78c95122196c" src="http://sitelife.livescience.com/ver1.0/Content/images/store/11/15/cb51e87e-8221-424c-8ff2-78c95122196c.Large.jpg" alt="blog post photo" /> </div>

thalion · Apr 30, 2005

I'm really pushing for the sails to work, but I can only be cautiously optimistic at this point. The delays are unnerving, though for what it's worth I'd rather it be delayed and go off right than hurried and fail. If it makes it off the ground and into space without a hitch, I'm going to take some "Irish medicine" to celebrate. <img src="/images/icons/wink.gif" />

R1 · May 6, 2005

I just realized this is only a plastic experiment. Isn't anyone working on a permanent type of sail? I hope we don't have to wait another decade for a more permanent construct. By the way, can a solar sail be used to: move things like the ISS to libration points and back? move the Hubble lower and higher, maybe even millions of miles away? move things from earth orbit to lunar orbit and back and forth? <div class="Discussion_UserSignature"> </div>

nacnud · May 6, 2005

No No Yes, but only light things. A solar sail would have to be huge to move a heavy object like the ISS

henryhallam · May 6, 2005

By the way, can a solar sail be used to: move things like the ISS to libration points and back? No, too heavy move the Hubble lower and higher, maybe even millions of miles away? Potentially with a very large sail, but why would you want to do that? move things from earth orbit to lunar orbit and back and forth? Too slow. Solar sails are potentially useful for cheaper missions to the outer planets, but not for anything much closer than Mars. Even for Mars it is doubtful whether the long flight times make it worthwhile (would only be for cargo). An annoying feature of solar sails is that they cannot tack - the force exerted is always directed outward, directly away from the sun. This is definitely not the most efficient way to raise your solar orbit (e.g. for a trip to Mars) - instead you should thrust in a posigrade direction, that is in the direction of your motion i.e. tangent to your orbit. However, for trips out to Saturn and further, the orbit shape is such that the posigrade direction and the outward vector from the sun get nearer to being in line, so the loss is not so bad. Edit: Thinking about it more, by tilting the sail from side to side you can direct the thrust in an arc 45 degrees to either side of the antisunward direction, but the effective thrust is reduced.

R1 · May 7, 2005

1) do we have plans of building a real solar sail at all? or is Russia in charge of the sailing 2) could a solar sail push a small probe into a fast orbit around the sun. I'm talking about high speeds, like between 70 and 90 percent c I know it might take a while, but how long? <div class="Discussion_UserSignature"> </div>

grooble · May 7, 2005

How fast does the galaxy itself move?

yurkin · May 7, 2005

You can indeed tack solar sails. You just have to reflect the sunlight so that the angle of incident is less then 90 degrees from the direction of rotation and you’ll slow down. Slowing down will cause you to drop your orbital altitude.

nacnud · May 7, 2005

Depends on the velocity of the thing you measure it against.

henryhallam · May 7, 2005

For example the Earth's velocity in it's orbit around the sun is .001 C, as you increase the velocity you move further from the Sun. I think you missed a zero there Dave, 0.001 c = 299.8 km/s, Earth orbit velocity is about 29.7km/s. ou can indeed tack solar sails. You just have to reflect the sunlight so that the angle of incident is less then 90 degrees from the direction of rotation and you’ll slow down. Slowing down will cause you to drop your orbital altitude. I keep getting my facts wrong <img src="/images/icons/frown.gif" /> Should have drawn that one out on paper rather than trying to think it through in my head.

R1 · May 7, 2005

well could the sail reach 70-90 percent c at least? I guess it doesn't need to stay in close orbit, but could we keep it close enough to the sun to reach such a high speed? I mean even the orbit of a comet goes near enough to the sun from time to time to catch more wind. would it even reach such speed at all? Its the speed that would be needed more than the proximity to earth. <div class="Discussion_UserSignature"> </div>

star_sirius · May 8, 2005

I'm aware of that John1R, but if Cosmos 1 will be successful, that would mean a lot to the solar-sail projects within the space agencies and perhaps one stage ahead. I heard the NASA could set the earliest solar sail in 2009. Yes, right now Japan (JAXA) is the world leader of solar sails, they had tested 10m pinweel shape solar sails last year, the testing of 20m solar sail is coming as early as May. The final goal for JAXA mission is to combine a 50m solar sail with an ion drive which has a capability to put a probe in orbit.... yeah... that could mean your questions 1,2,3 as easy as a,b,c. It's all depending on the sizes of the vanes, your questions 1,2,3 should be attainable without an ion drive, but that would need sails perhaps 5-10 times bigger than Cosmos 1. <img src="/images/icons/wink.gif" /> The ultimate NASA's long-term goal is to place a Particle Acceleration Solar Orbiter in stable orbits between Earth and the Sun with a much bigger solar sail than Cosmos 1. <div class="Discussion_UserSignature"> A dazzling bluish luminosity from A distant south pacific. <img id="cb51e87e-8221-424c-8ff2-78c95122196c" src="http://sitelife.livescience.com/ver1.0/Content/images/store/11/15/cb51e87e-8221-424c-8ff2-78c95122196c.Large.jpg" alt="blog post photo" /> </div>

henryhallam · May 8, 2005

The final goal for JAXA mission is to combine a 50m solar sail with an ion drive which has a capability to put a probe in orbit In orbit around what? No solar sail or ion drive could launch from the surface of any planet or moon into orbit. If you meant capture into orbit, SMART-1 already did that with the moon (but I don't know how well that would work for something further out, I think the intercept velocity would be too high for orbit capture by ion engine)

star_sirius · May 8, 2005

Oops! Around planet Jupiter's poles and perhaps even fly past few large asteroids. <img src="/images/icons/wink.gif" /> <div class="Discussion_UserSignature"> A dazzling bluish luminosity from A distant south pacific. <img id="cb51e87e-8221-424c-8ff2-78c95122196c" src="http://sitelife.livescience.com/ver1.0/Content/images/store/11/15/cb51e87e-8221-424c-8ff2-78c95122196c.Large.jpg" alt="blog post photo" /> </div>

henryhallam · May 8, 2005

Ah - that sounds doable, if it was a high orbit. Should be an interesting project. This sort of thing would allow a lot more cheap science missions, even if they take a little longer to get there.

R1 · May 9, 2005

Well thanks, everyone, for the updates/ discussion. <div class="Discussion_UserSignature"> </div>

meteo · May 9, 2005

Just did some quick calculations a solar sail traveling at 70%C hitting a 1-micro gram particle. Relativistic kinetic energy of the 1-micro gram particle is equivalent to about 17 lbs of tnt. Realtivistic kinetic energy of a 1 gram particle at this speed is equivalent to a 8.6 kiloton nuke. At 70%C realitivistic KE is about 40% more than regular KE. Flying through the solar system is a bad idea! <img src="/images/icons/smile.gif" /> Edit: After doing the caculations I remembered even using lasers your limited to 10-25%C IIRC. Realivistic KE at those speeds is only a few % higher than regular KE but the energy is still pretty impressive.

rybanis · May 9, 2005

Heck I think I would be weary clear out into the Oort cloud. Anywhere where there are bits of comet and dust floating about. Even in interstellar space theres the chance you might come across something larger than the ISM, given the tremendous distances you must travel to get anywhere. <div class="Discussion_UserSignature"> </div>

chebby · May 10, 2005

One thing that I find amazing is that the sail gets pushed twice, once as the light hits, and one more time when it is emitted from the angle of incidence. The net force is at a 90 degree angle towards the opposite side of the spacecraft (there is also some force just at the incoming angle's vector as not all light is reflected.) It occurred to me that the better the reflectivity is, the better (stronger) is the push. Also, reflectivity of higher frequencies is more important as they carry more energy. Would a regular mirror reflect x-rays or at least utra-violet light? The article mentions that direction can be changed by changing the tilt of the spaceraft. I think that tilting a spaceraft that large may require too much force (or at least put too much stress on the spacecraft). Another way to do it is to change the amount of light reflected by using special materials (maybe fluid inside glass?)

mental_avenger · May 10, 2005

You can indeed tack solar sails. You just have to reflect the sunlight so that the angle of incident is less then 90 degrees from the direction of rotation and you’ll slow down. That old illustration has been haunting the internet for years. The illustration does not take into account the rotation of the solar sail by the pressure of the sunlight. As presented in the illustration, the solar sail would simply rotate to either perpendicular to the solar light, or parallel to it, neither of which will provide any increase or decrease in orbital velocity. It is amazing how many times this totally inaccurate model has been referenced. <div class="Discussion_UserSignature"> Our Solar System must be passing through a Non Sequitur area of space. </div>

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