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NASA Cancels "Sunjammer" Solar Sail Demonstration Mission
An anonymous reader writes "Space News reports that NASA has cancelled its solar sail demonstration mission (also known as Sunjammer) citing "a lack of confidence in its contractor's ability to deliver." "Company president Nathan] Barnes said that in 2011 he reached out to several NASA centers and companies that he believed could build the spacecraft and leave L'Garde free to focus on the solar sail. None of those he approached — he only identified NASA's Jet Propulsion Laboratory in Pasadena, California — took him up on the offer.
Rather than give up on the opportunity to land a NASA contract, L'Garde decided to bring the spacecraft development in house. It did not work out, and as of Oct. 17, the company had taken delivery of about $2 million worth of spacecraft hardware including a hydrazine tank from ATK Space Systems of Commerce, California, and four mono-propellant thrusters from Aerojet Rocketdyne of Sacramento, California."
And in related news, an earthquake was reported in Sri Lanka
(A.C. Clarke turning in his grave)
A vote of no confidence. I remember when NASA canceled the USNO FAME satellite - they said it was over the budget, but really it was over the management team. I expect that there is something similar here - fortunately, there is still NASA Marshall's Solar Scout, which is much smaller and cheaper than the Sunjammer.
I wonder how much they've been paid or are being paid.
PerkinElmer is still in business, by the way.
Do not look into laser with remaining eye.
Whenever NASA (or any other agency) cancels a contract because they lack confidence in the contractor, it probably means that someone in the government is paying attention to what's going on, and is holding the responsible party's feet to the fire.
Compare this to situations where billions of dollars of money are tossed away in the pursuit of unworking (and possibly unworkable) missle defense systems.
Koans and fables for the software engineer
Wrong guess, minus five.
Hint: the pound is a unit of FORCE, the kilogram is a unit of MASS. It makes no more sense to measure thrust in kilograms than it does to measure distance in square meters.
If you really want to have consistency, they should have measured the thrust in newtons, NOT in kilograms.
The fact that Europeans (at least one of them) don't know their own measurement system any better than that is appalling....
"I do not agree with what you say, but I will defend to the death your right to say it"
The Planetary Society's LightSail project is apparently still on track, so Clarke (and we) shouldn't despair just yet.
It's worse than that. There are slugs, pounds and poundals, and (IMHO) anyone who doesn't immediately convert these units to MKS is just being silly.
Sunjammer was to have a total surface area of ~ 1,200 square metres, so its thrust at 1 AU would have been 2 x 1361 W / m^2 x 1200 / c ~ 0.01 Newtons (assuming the sail had a near perfect reflectivity). On the surface of the Earth, that thrust would be generated by a weight of 0.01 / 9.8 ~ 1 gm, or ~ 0.002 pounds.
for what it's worth for GP and anyone else who's interested, 1 lb thrust = 4.45 Newtons. I like this analogy I found online: If you were floating in space with a bag of baseballs and you threw one baseball per second away from you at 21 mph, your baseballs would be generating the equivalent of 1 pound of thrust. If you were to throw the baseballs instead at 42 mph, then you would be generating 2 pounds of thrust. If you throw them at 2,100 mph (perhaps by shooting them out of some sort of baseball gun), then you are generating 100 pounds of thrust, and so on.
Pounds are units of both mass and force, which is a problem with the "standard" system of weights and measurements. Usually there is a distinction made if it is ambiguous and matters (lb_f or lb_m). It's my understanding that this is because the unit was named before the concepts of mass and weight were observed to be different, but that may be apocryphal.
The tragedy is that Europeans are apparently determined to screw up a perfectly good unit system by adding back the ambiguity in the creation of the kilograms-force unit (kg_f).
Can you be Even More Awesome?!
They all seem to do it - Space.com, Spaceflightnow.com, Spacefellowship, Nasaspaceflight. They know their audience is educated yet they persist in writing articles with both metric or imperial units. Or worse, they mix them as in this instance. They also take the let-me-convert-everythgin-for-you approach and put the complementary units in parentheses. Why they don't just stick to one measurement system - SI makes the most sense - I do not know. However I do believe spaceflight enthusiasts are NOT idiots.
Pound as well as kg are measures of mass.
In both cases the measurement is done by 'looking at' the force such a weight exercises in the earth gravity field on 0 above sea level.
It is a no brainer that mass and force excersiced by that mass is completely equivalent for any daily ordinary men usage.
So what was the point you wanted to make with your wrong reasoning?
Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
I remember one of my brother's first issues (Apr? 1964) of Boy's Life having "Sunjammer" as the cover story. AC Clarke later expanded the story under the name "Wind from the Sun". FWIW, Boy's Life is one of the magazines digitized by Google Books and you can look up the issue in question.
A Shadeless room is a brighter room.
a windjammer* is a vessel designed to take full advantage of every bit of wind energy it can capture and put it into forward motion using the largest sail area it can possibly handle. Hence the name "Sunjammer", being designed along the same line: the largest sail the payload can practically handle using the lightest material available with just one aim: to maximise the conversion of the solar wind thus captured into forward motion.
*oceangoing windjammers were steel hulled and designed to carry cargo on intercontinental voyages following the prevailing winds. Maximising sail areas (usually by adding more masts and square riggings, as opposed to racing boats which used one to three large sheets and were designed for speed rather than capacity) allowed cargo capacities to be increased for sailing ships until they hit an average 2,000 tons, with the largest being just over 11,000 tons full displacement (the Preussen), while being able to maintain high cruising speeds (sometimes in excess of 18kt)
Political debates have me rolling my eyes so much I think I got optical whiplash. I should sue. - Foamy The Squirrel
When doing physics the pound is most often used as force, but it's not quite as simple as you make it out to be.
http://en.wikipedia.org/wiki/P...
Also, consider the system of measurement with pounds-as-mass, where the unit of force is the "poundal".
The fundamental property is mass, and the "weight" is defined by the force generated due to "standard" gravity.
The kg is a measure of mass. The pound can be mass or force, depending on the system of measurement involved. Most technical people would consider pounds to be units of force, where the corresponding mass is the slug. (Though honestly SI units are more convenient for doing physics with.)
true, nor do Europeans measure speed in miles per hour. the equivalence would be relating one Newton to the thrust imparted on you when you kick a football away from you at XX km/hr. presumably it's a balance-of-kinetic-energy equation. I challenge Slashdot to solve this eqn!
I'm pretty sure in the UK a wind jammer would be known as a clipper.
nope. Clippers are wooden hulled. Windjammers are at least four times more massive and steel hulled.
Political debates have me rolling my eyes so much I think I got optical whiplash. I should sue. - Foamy The Squirrel
What was the detector? 24 wafers isn't as absured as it may sound, for a one off prototype. Developeding a high yield process takes a lot of time and money, especially if it's a relatively new material system.
There's a lot of ruins in Mesopotamia.
No brain, no pain.
A British pound is the unit of force with which the upper class "pound" the working classes to submit to voting for the same lackeys time and time again. A US pound is very similar but may also relate to the amount of pressure exerted on one's hind quarters whilst consuming a triple big mac with a large fry and 42 oz fountain drink that contains enough sugar to give a hippo diabetes.
Ahem.. Baseball is pretty much the national sport next to ice hockey in Finland. Although it's the local version of the game. Pitching is vertical instead of horizontal(US baseball) and the field is shaped like a upside down triangle with a rectangle on top rather than diamond(US)
There are no atheists when recovering from tape backup.
FAME deserved it. Let' s just leave it at that and walk away from the wreckage.
The detector was CCD. It wasn't supposed to be a advance the state of the art, it was supposed to be we want a functional 2kx4k detector.