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Solar Powered Helios Plane Destroyed in Test Flight
deglr6328 writes "NASA's solar powered Helios airplane has crashed into the Pacific off the coast of Kauai today during its first test using a regenerative fuel cell power supply. Helios held the record for highest prop propelled plane altitude at 96,863 (set 2 years ago) and was making preparations for a 96 hour continuous flight using its 62,000 solar cells during the day while electrolyzing water into hydrogen and oxygen for use in its fuel cells at night. With the capability to carry 200 lb. to near 100,000 ft. for months on end, Helios was eyed with great anticipation by scientists and RF telecommunications buisnesses alike."
I'm actually rather curious about how it is (er, was) constructed. It looks quite flimsy...
In case you didn't RFTA, the craft was an unmanned, remotely controlled plane. The article blurb didn't make this clear. So don't worry, everybody, nobody got hurt. (Except for maybe a few egos =)
[SIG] It's like putting a moose in the blender -- a recipe for disaster!
It was the first flight for the fuel cell system. Apparently in your hurry to post you missed this modicum of detail.
Wow, thats really depressing; i was there a few years ago (barking sands, kaui) for one of the first test flights, maybe the first? i dont know, but it was early on... really cool, it folds up into a huge U at takeoff... anyway, im sad to see it go, i have a poster on my wall; maybe i should stamp Time Of death on it?
i was also there for the Pathfinder (earlier prototype) tests, at barking sands, as i have a friend who works there, and can get me in...
Maybe NASA will scoop up the wreckage, figure out what went wrong, and then build another one
;-)
The last line of the article says:
Brown said NASA intends to develop another Helios aircraft, calling it "technology worth pursuing."
(This just proves that i read the article before posting
Yes, it is clearly a first flight for a new component the first time it goes up. Because the new part hasn't flown, it's first time in flight is a first flight for that part. Not necesarily important, but definitely worthy of concise qualified mention.
Also, the entire point of the flight on which it crashed was as a first test of the fuel cell in the actual environment in whichit was designed to operate, so it definitely deserves mention as a first for the system.
The pens were created by Fisher pens, at the cost of fisher pen inc. and given freely to NASA.
I wonder how much that thing weighed. Anyone have a link somewhere to specifications on the Helios?
6 8-DFRC.html
The specs of Helios are one click away from the article to which slashdot links to. Maybe next time you could check the story before you start posting.
http://www.dfrc.nasa.gov/Newsroom/FactSheets/FS-0
--- Sigmentation Fault - Comments Dumped
It's a very flimsy looking aeroplane. A 247 foot wingspan (a longer wingspan than the 747) that bends into a shallow U when aloft, with an all up weight of 1323 pounds (about the same as a light aircraft with no fuel or people in it) it looks like it wouldn't take too much to exceed its structural limits - some heavy wind shear or possibly a control surface stuck out of true.
Website here if you want to learn more.
Oh yeah, and how about a new moderation category?
"-999 Oh my god not those tired old chestnuts AGAIN" for all the fuckwits who have nothing better to do than drag out the tired old jokes every time someone mentions NASA here, as well as all the other pathetic unfunny crap that you losers repeat over and over and over again!
"Information wants to be paid"
IAAA (I am an aerodynamicist), I really don't think the hole (unless it covers a huge portion of the wing) would be a problem that can't be overcome. To really screw the aero up you have to have flow going where it is not supposed to, my suspicion is that the wing would quickly reach an interior pressure equal to the pressure on the outside at the hole, resulting in a very small amount of flow entering or exiting the hole, kind of an automatic gas patch...
That point aside, if they had made it further into the atmosphere without loosing structural integrity of the crew compartment they could have survived. After the Challenger (I think) they came up with a crew escape technique that works by sliding the astronauts down a pole (to clear the wings and such) and parachuting to the surface, but it doesn't work until after entering the atmosphere...
"I'll have a Guinness, no wait, make that a Coors Light" -Grad student I work with, who shall remain anonymous...
Joking aside, it actually is a good idea. No commercial air flights, non-commercial flights tightly controlled, all other "interesting" flights scheduled well in advance. It's about the best place I can think of to get 4 days of uninterupted flying, guarenteed.
-JS
Vanity of vanities, all is vanity...
Posted AC because I do not have a /. account.
IAARS. (I Am A Rocket Scientist.)
One question that has plagued me since the destruction of Columbia: If there wouldn't have been extreme heat going into the wing, would the crew still be alive? I'm no aerodynamics expert, but isn't it possible, at the point of entry into the atmosphere, when temperatures start to rise, that the shuttle release some liquid nitrogen or some other super-coolant in some manner as to keep homeostasis of the vehicle?
Upon reentry, the Orbiter (the white and black plane-lookin' portion of the Shuttle), is carrying no cryofuels. They are stored in the large red-orange External Tank, and used up during launch. The Shuttle uses LOX and LH2, both of which are f'nasty to deal with and are economical only to generate the immense thrust necessary to achieve orbit. While in orbit, the Orbiter maneuvers using (relatively) small hydrazine thrusters. N2H4 is also f'nasty, but somewhat less so than either LOX or LH2. NASA's Shuttle Basics website provides a good nontechnical overview of mission stages.
The Orbiter doesn't maintain homeostasis during reentry. The bottom gets really, really, really hot. Because the Orbiter is essentially falling back to Earth, the crew wants to bleed off as much speed as possible. By taking advantage of friction with the air, the Orbiter can slow down, and not be travelling at Mach 20 or so when it lands. It is a tricky balancing act among speed, attitude, and heat--the tiles can only absorb so much thermal energy, the crew has only aerodynamic control of the Orbiter's attitude, and there is a whole lot of kinetic energy that needs somewhere to go.
From my understanding of the physics of reentry, and the information available about the Columbia breakup, I do not think that the only factor was heat. The speeds at which spacecraft travel during reentry are so far beyond the speed of sound that aerodynamicists classify them not as supersonic, but hypersonic. The hypersonic regime (generally > M5) is somewhat counterintuitive. Friction with air generates enough heat at reentry speeds (M20 and up) to vaporize graphite and cause dissociation in N2 and O2 molecules, creating an ion cloud around the spacecraft.
We would not be able to travel at hypersonic speeds if not for a quirk of geometry. If you look at a supersonic vehicle, such as the X-1, you will notice that the leading edges of the wings and fuselage are pointed and form very sharp angles. This causes the shockwave formed by supersonic speed to break cleanly around the vehicle, which is good for aerodynamics. If you look at a hypersonic vehicle, like the Orbiter, you will notice a blunt, rounded leading edge and nosecone, which causes the shockwave to separate from the craft, forming a cushion of air. This insulates the Orbiter somewhat from the heat of reentry.
If that rounded profile is compromised, in Columbia's case by loss of tiles on the leading edge, the shock will break as in a supersonic craft, allowing both heat to transfer to the wing, and also subjecting the Orbiter to the considerable kinetic forces generated by air resistance. Heat did not tear Columbia apart. Her own speed did.
-Carolyn Lachance
Not to be a stickler here, but the Apollo 1 accident didn't really have anything to do with the fuel (alluded to in the "...renewable energy that doen't[sic] blow up...")
Apollo 1 was a result of pressurizing the capsule to simulate the pressure of being in orbit. That pressure environment, coupled with frayed wiring and the amount of velcro was the primary cause for The Fire.
But your point is valid, IMHO.
sad robot making broken music
Call me naive, but isn't the fact that physical fuel disappears once it is used make it attractive for planes, because it decreases the weight as fuel is used? Why did anyone think that putting big fat heavy batteries (albiet hydrogen-based) would be a good idea for planes?
Because conventional fuels aren't renewable in-flight.
How is a vehicle that renews its own fuel by solar power, enabling 24x7 flight without refueling, not better than a plane that has to be land or be refueled every so often?
>IAARS. (I Am A Rocket Scientist.) ...
>
>The Shuttle uses LOX and LH2, both of which are f'nasty to deal with and are economical only to
>generate the immense thrust necessary to achieve orbit. While in orbit, the Orbiter maneuvers
>using (relatively) small hydrazine thrusters. N2H4 is also f'nasty, but somewhat less so than
>either LOX or LH2.
???
The OMS uses hydrazine / nitrogen tetroxide, which is way, WAY more nasty than LOX / LH2.
LOX / LH2 are cryogens, and contact with them will give you frostbite. Hydrazine is carcinogenic and toxic, but nitrogen tetroxide is roughly as poisonous as the best war gasses from WWI. Plus, it has very low surface tension, so when it spills, it spreads extremely rapidly, which causes it to vaporize even faster than the already high vapor pressure would indicate. The various oxides of nitrogen are famous for the "BFRC" ( big red cloud ) that results from spills, which you should run away from very fast.
John Carmack
Let me tell you as a RF technician for a national wireless cellular company that there is NO WAY that 200lbs. comes EVEN CLOSE to what you need for equipment. A minimum of 1k lbs. will have to be up there. Also, not to mention that the picture that that company shows with the plane supposedly transmitting down to that entire city would have to carry an assload of frequencies. Need for more frequencies = Need for more equipment. There's no way that plane could carry enough cellular site radios to transmit/receive to/from all the users a city the size depicted in that picture! Not even close. Floating planes transmitting to customers is no where even close to becoming a reality.
Then there's one last problem. The problem of risk. The risk of having a cellular shelter go up in flames is extremely low. The risk of having a high tech plane fall out of the sky for whatever reason (wind shear, fuel out, human error) and damaging your $13,000 a piece cellular radios is extremely high... (compared to that of traditional methods of transmission). This cost is only that of the actual radios. There's much more cost and weight associated with a cell site.
If you were the CEO of a cellular company, you'd have to be a complete friggin' moron to think this has any chance of becoming real anytime relatively soon.
Wherever you go, there you are.