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Solar Sail Craft Damaged
C. Mattix writes "It looks like we won't know if the solar sail will work for a while. There was an accident prior to launch that will delay it for quite some time. Full story from Yahoo."
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they were probably setting up a solar still with the mylar to make vodka from potato peelings.
They asked that you return the DVD of "Capricorn One" and said that you owe $23.17 in late fines.
[Philip Michael Kramer ate my balls.]
If it generates EMF via induction then this cannot be used to maintain orbit. Every bit of energy you get from the tether is bought and paid for by magnetically induced drag. So what you have done is to convert potential and kinetic energy into electrical energy (minus some losses). You cannot then convert the electrical energy back to kinetic and potential and end up with more than you started with. Plus there is the problem that you must still expend fuel to change the orbit.
If the tether really works via induction, what you could do in principle is to drive it backwards with the power you get from elsewhere (solar cells, plutonium rtv, et al). Then you are effectively creating a magnetic field which pushes against the earth's field and lifts your orbit.
I've been hearing about Solar Sails since before '91 (year I graduated high school). I had heard there was at one point a race scheduled for 1992 for around the moon and back (in honor of Chris' Columbus' 1692 voyage)... but that fell through. And on and on and on it has gone for 10+ years. I'm convinced that there's some conspiracy keeping this technology from being 'tested'... Ok.. maybe not... but damn! Ten years and still not shit to show for it.
I heard the tourist dude stepped on it.
the greys have damaged the craft because they heard we were getting together a ship for the 2005 galactic cup.
sheesh! once again the slashbots dive right in without being familiar with sailing tradition.
more likely it was a software problem.. a little too much code reuse between the testing and deployment packages
It's too big a coincidence that an accident like this would happen right when America was trying to launch its next generation of space craft. There are no coincidences in this world. It must have been Russian sabbotage.
The Russian space agency must be reeling, now that MIR is out of the sky. They were once a proud nation with a proud space heritage, but now they're a third-world grounded nation begging for international aid from the west. That has to hurt.
So what do they do? They sabbotage America's glorious space program. They're jealous of our potential and they're jealous of our success. They never forgot that we were the first nation in history to successfully fake a moon landing, and they won't forgive us NASA's recent successes with missions to Mars. Worse than that, we insulted their collective genitalia with Taco Bell's publicity stunt which put a target in the Pacific ocean for MIR to land on.
NASA is far too clever to have caused this accident by their own incompetence. America is too strong a nation to let such accidents get in the way of our manifest destiny. We must find the spy who committed this act of terrorist espionage and bring him to justice.
The Cold War is very much alive.
conwstruction of a mirror that effectibely focuses this energy into
the space required is another matter addressed elsewhere . . .
>P>
hawk
hawk, sticking to what he knows . . .
> the square of the distance is it not?
No, it is not.
That is the density for a point source that is radiating in three dimensions. For a lossless focused mirror, the density would be the density at the point of the reflector times the ratio of the area of the reflector to the area of the target. This has to be adjusted for losses at the mirror (less than full reflectivity) and through the air (you hit molecules and disperse, and what's left will be ionizing the air near the target).
hawk, actually a physicicst among his many hats.
that the pyrotechnic circuits work.
From what I recall, it wasn't a micrometeorite that did the tether in.
They were doing experiments with electricity generation with tethers, and they found that much more electricity was generated than expected. The tether broke, and when they landed they insepected the severed end. It had been burned through by an electric arc, which gives you a good demostration of generating electricity by moving a wire at speed through the earth's magnetic field.
If tits were wings it'd be flying around.
You don't need to expend fuel to change the orbit. Put some solar cells on your spacecraft, and you can send a current down the wire to act against the magnetic field. How about that? You've used solar power to maintain your orbit. This is a neat tether trick which would be very useful.
If tits were wings it'd be flying around.
I'm glad it hasn't been launched, solar sails are far too dangerous to be allowed in orbit.
Before you condem me, think of the facts. They are talking about orbiting a huge, acre sized, piece of mylar, with controls to change it's orientation.
It's a giant space mirror!
For those of you didn't read the Mars trilogy, think back to the first time you played with a magnifying glass in your backyard.
Because far too many people seem to be taking this (hopefully) humorous post seriously:
While you could fry things magnifying-glass style with a concave mirror, you won't be able to with a solar sail. To focus light properly at all, the mirror would have to have a very precisely controlled shape. You *could* put a complicated and heavy support structure around a space mirror to adaptively shape and focus it, but you sure as heck won't see this on any solar sailcraft.
Sailcraft don't need to focus light; they just need to reflect or scatter it more-or-less backwards (or at least, less forwards than it was when it came in). Thus, they don't bother with heavy focusing gear, and so wouldn't be able to burn holes in anything if they tried.
Well, I can't speak for anyone else, but I'm paying attention to this project because it's interesting.
If I ignored everything connected to anyone who might have some weird ideas, I'd have to stop reading Slashdot. Hell, I'd have to stop reading, period.
Hello, hello, this isn't a NASA project. End of message.
Mod down posts with a "Free Mac Mini/iPod" sig, they're spam!
I have a 3 foot fresnel lens that can melt *granite* on a sunny day.
And what is the distance of the focal point? The energy density at the focal point is inversely proportional to the square of the distance is it not? Will the huge sail even have a distinquishable focal point?
Aah, change is good. -- Rafiki
Yeah, but it ain't easy. -- Simba
Sounds like they forgot to use the -n option ;-)
while testing.
--
Sometimes boldness is in fashion. Sometimes only the brave will be bold.
You have: 5422809.3watts/yard^2
You want: watts/in^2
* 4184.2664
In other words, your original calculations were pretty good. (my mistake).
--
Sometimes boldness is in fashion. Sometimes only the brave will be bold.
I'm sailing! I'm sailing! I'm SAAAAIIIIILLLLLLLIIIIIIINNNNNNNGGGGGGGGGG!
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crazy dynamite monkey
That's absurd. Have you ever played with a fresnel lens? I've used one square foot of focused sunlight to burn holes in non-metals (including my hand :(!
For the unscientific, read the link below to see how a 3' circle of sunlight, concentrated to a square centimeter, can melt Aluminum. For the lovers of conversion factors, read on:
I'm going to trust an astrophysics grad student for a conversion factor on this one (http://www-personal.umich.edu/~bclee/lens.html). He says the sun puts out 1340 Watts/m^2 at the Earth's surface, before atmospheric absorption. Mississippi State says there are 43,560 square feet in one acre. My trusty ti-83 says that 1 acre * 43560 ft^2 / acre * (12 in)^2 / (1 ft)^2 * (2.54 cm)^2 / (1 in)^2 * (1 m)^2 / (100 cm)^2 * 1340 W / m^2 = 5.4 megawatts from one acre of sunlight.
My light bulbs put out 100 Watts over somewhere around 4*pi*(3 in)^2 (yeah yeah that's a great approximation :), making 113 in^2. About 1 Watt / in^2. As opposed to 5.4 megawatts spread over a 3 foot square, as you said, which yields (5400 kilowatts) / (36 in)^2 = 4.2 kilowatts of power per square inch. Ouch!
This is all fraught with inaccuracy, and the atmosphere does soak up quite a bit of radiation, but I sure hope i'm not off by a factor of 4,200. Did I miscalculate something?
The solar foils added to ISS/Alpha recently were half an acre in size. This means that if aligned nicely, you can see ISS/Alpha with your unaided eyes. Oooh, the danger. I'm afraid.
If you can focus all of the solar light that hits an earth-acre space, into a much smaller space (say, a 3' square) on the ground, yes, it's gonna be hot and perhaps dangerously hot. But not weapons-grade dangerously hot.
You've been reading too many scifi novellas.
[
From the article I got this vision of someone pushing the "go button" and then having the entire sail unravel inside of a small lab filled with engineers.
...... Oh. Hi. No problem. Just testing. We'll get this fixed. Everyone grab a corner."
"AAaAGGHHH! Not that button!" - As they're all tangled in foil and squashed against the ceiling. - "Real cool Yuri. Now help me get this folded back up before they come
Jon Sullivan
Jon Sullivan
www.jonsullivan.com
Keep in mind, this is not a NASA project. This is a privately funded experiment. NASA has no interest in really pursuing new propulsion techniques. That's why the ISS hasn't been (or isn't even planned to) outfitted with a MEDS style electrodynamic tether for orbital maintenance. An EDT would reduce (if not remove) the dependance on costly space shuttle and Progress space freighter flights to boost its orbit against atmospheric drag.
An interesting note, this solar sail is to be launched atop a former ICBM from a submarine. That, my friend, is the essence of cool.
This isn't government, this is a PRIVATE company. Other than that you're right on track!!! Microsoft and the RIAA will use this new space weapon on anyone who turns an XBox into an MP3 web server!!!
.sig
That's why I'm patenting my new "SPACE-LASER-FACE-NOT-BURN-OFF STUFF" (TM). If you send me $20 I'll send you a WHOLE ROLL of tin foil so those nasty buggers don't melt your face or your MP3 collection. Hurry! Before it's TOO LATE!!
G.H.
This is NOT a
Just wait till some crappy band steals your nic.
You said ti yourself, it's a mirror, not a magnifying glass.\ =\=\=\=\
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First a bunch of both Soviet and US failures near/on Mars. Now the events happen even here... Coincidence? Conspiracy? You decide :)
"The right to figure things out for yourself is the only true freedom everyone shares. Go use it"-R.A.Heinlein
But some of the prototypes that are overhyped, the makers of the item find a fatal flaw just before the maden use of the item and 'accidentally' damage it, delaying the use of it. Then they get the time to fix it with the update or patch that it requires.
Saves them from the embarassment of launching something that will not work. On the other hand it does end up with a correct item that works as expected so everyone is happy.
Again, just something to think about.
DanH
Cav Pilot's Reference Page
Cav Pilot's Reference Page
UNIX - Not just for Vestal Virgins anymore
with all the recent questions about nasa's funding, do they still have the capital required to repair/relaunch the craft? and if so, will /. care enough to cover it?
Mooniacs for iOS and Android
Are you on crack or someting?
First of all, mirror != magnifying glass.
Second, "scale that up to a beam of light"?!? I am left wondering what the hell did you shine through your first magnifying glass? Or did your parents think the combination of lenses and light were too dangerous?
Third, something in space that is acre in size is relatively tiny to a human observer on earth.
Cripes, man, you should write for Star Trek.
from the article:
Instead of the test, actual spacecraft operations began...
doesn't sound like a really tightly managed operation!!
Can't you see them testing their nuclear missiles? Oops! Actual missile operations began...
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A person of moderate zeal
Perhaps the peak of the solar cycle will have passed by then. IANAA (A=Astronomer), but I gotta wonder what a Coronal Mass Ejection would do to a thin sheet of mylar. Imagine not being able to AIM SolarSail1...
If you love God, burn a church!
Ewige Blumenkraft!
I'm glad it hasn't been launched, solar sails are far too dangerous to be allowed in orbit.
Before you condem me, think of the facts. They are talking about orbiting a huge, acre sized, piece of mylar, with controls to change it's orientation.
It's a giant space mirror!
For those of you didn't read the Mars trilogy, think back to the first time you played with a magnifying glass in your backyard.
Now, scale that up to a beam of light, a yard wide and more intense than a steel melting laser beam. Think what the beam of light could do to any cities or countries that don't kow-tow to the US-Russian space hegemony.
Worried yet?
Notorious Time Travel Crackpots
Thus proving what we developers already know: QA is the cause of all our problems.
Dancin Santa
But you can't. A perfect mirror can't focus a 1/2 degree wide source into anything smaller than 1/2 degree, as seen from the mirror.
That means the size of the image of the sun will be roughly 1/100 of the distance to the mirror. If the mirror is 300 feet away, it could focus the sun into a 3 foot circle, and you'd have to worry about it getting hot. But the sail is going to be hundreds of miles away, and won't add noticeably to the heat from direct sunlight.
There's no risk at all. The original post was a joke.
Construction of such a mirror isn't just hard, it's theoretically impossible. You can't focus the sun's image into a 3' circle unless the mirror is within 300'. You just can't.
The people talking about melting things with Fresnel lenses were using much shorter focal length lenses.
Think about the way camera lenses are rated: f/1 is a nice bright lens, able to concentrate a lot of light on the film.
A 3' Fresnel lens with a 3' focal length is an f/1 lens. I don't know the actual dimensions of the solar sail, but if it's an acre in size, it's around 200' in diameter, and it probably needs to be at least 100 miles from its target, so it's going to be like an f/2500 lens. An f/2500 lens is 6 million times dimmer than that Fresnel lens.
The sun isn't a point source. It's about half a degree across, as seen from here.
Its image will be about half a degree across, as seen from the mirror.
If the mirror is 100 km up, that means the image of the sun will be around 1 km across.
It won't be very hot, unless the sail is much bigger than that.
How can you say this wouldn't be "weapons-grade hot"? I have a 3 foot fresnel lens that can melt *granite* on a sunny day. That's only 9 square feet... Now, imagine a lens covering several acres (not to mention that this is unfiltered sunlight) - you could project a beam capable of burning through nearly anything on Earth! We should probably make a point of grabbing some extra sunblock this year.
"Leave the strategizing to those of use with planet-sized brains." -Tycho
"Leave the strategizing to those of us with planet-sized brains." -Tycho
Just next to the damaged section of the solar sail you can find this mysterious iconic encryption. "Designed for Windows".
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Free Iran
``At this point it will be at least a three-week delay and it could be more than two months,'' Friedman said.
Three weeks to two months? Most space missions are in terms of years, I don't think this is a major setback.
The project is sponsored by Cosmos Studios, an entertainment company founded by Ann Druyan, widow of the late astronomer Carl Sagan, and Joe Firmage, a Silicon Valley entrepreneur and part-time UFO investigator.
Now I'm suspicious. Why are we paying attention to a Russian project, funded by an entertainment company, and promoted by some UFO nut who believes in aliens?
Solar sails could be useful I suppose. As one insightful poster mentioned awhile back (qpt), it's good to explore a non-polluting source of energy. We don't need to go filling up space with our filthy combustion fuels, and using atomic radiation as a power source. All the clean, reliable power we need can be obtained from our sun!
"If the Lord had meant for us to fly, He'd have given us wings with which to soar...." William, 14:35