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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."
...Icarus.
Appropriate name too.
Anyhoo, it's sad to see such a technological marvel crash into the pacific ocean like it did. Maybe NASA will scoop up the wreckage, figure out what went wrong, and then build another one. It would be great to see what we can learn from Helios in general, and not just on an aviation or RF use either. I mean in the field of solar electric generation, and how even in the Aerospace industry it has it's benefits and drawbacks. I personally would love to be using solar electricity instead of having to pay the electric company, but alas, we can't always get what we want...
KevX45
"Now there's a look in your eyes, like black holes in the sky"-Pink Floyd
...because our history is full of science which worked as expected from the start. If it's too complicated to get right the first time, it's not worth doing. Failure depresses people, so only fund guaranteed successes. It's obvious, isn't it?
All in the name of science after all. Good thing whatever went wrong happened in the prototype phase, before anything but monetary anticipations were relying on it.
I'm very interested to know exactly what went wrong. From what I briefly read, I'd imagine it was the actual construction which had a problem, not the technology. Unless this was a pre-flight damaged part, this could be valuable information as I'm sure this plane used the latest designs, as other planes will be using.
This is why I went into software instead of Engineering. When my program fails, I reboot / recompile / restore the drive ... whatever.
I bet a lot of mechanical engineers wish they had a restart button.
Two thoughts. First, this is unfortunate, but it is what happens when you push the boundaries. It isn't safe on the cutting edge.
Second, if we want more funding for an agency then a strong case for it must be made. We shouldn't fund NASA just because it is NASA. NASA has done a poor job of creating a vision for what can and should do. It isn't clear to me why they should continue at current budget levels. I wonder if part of the reason is that it has become a government agency that is more focused on sustaining itself then offering a service to the people it serves.
Apparently it's going to beat that ~96000 record the Helios set, but won't be officially eligable because it's not going to take off under it's own power.
The balloon that launches it is fairly impressive too:
"As tall as the Empire State Building, their manned envelope will be the biggest ever flown."
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