LaserMotive Finds Success In Space Elevator Competition 258
Bucc5062 writes "LaserMotive has achieved the first step towards the creation of a working space elevator by qualifying for the $900,000 prize in a contest sponsored by NASA. To achieve this first level, LaserMotive needed to propel a platform up a cable dangling from a helicopter at over 2 m/s. They hit a top speed of 4.13 m/s. The next level of qualification will be to achieve a climb speed greater then 5 m/s. LaserMotive beamed roughly 400 watts of laser power to a moving target at a distance of 1 kilometer, as part of the vertical laser alignment procedure. The target was a retro-reflective board a little larger than 1 meter on a side. The contest will continue for another two days with at least two other teams challenging for the prize. To win the Power Beaming competition, the LaserMotive system uses a high-power laser array to shine ultra-intense infrared light onto high-efficiency solar cells, converting the light into electric power which then drives a motor. 'Our system will track the vehicle as it climbs, compensating for motion due to wind and other changes. Building on our experience from last year’s competition, we are designing an improved system able to capture the full $2,000,000 prize.'"
Re:Professor Myrabo at RPI (Score:3, Insightful)
I was thinking about the test and the first thing that came to mind is: ok they're beaming up radiation of some sort, probably more-or-less straight up, (since basing the power at the same spot the platform is tethered makes sense) and they're suspending it from a helicopter.... which would place the platform approximately directly between the beam generator and the heli...
so isn't this going to be a little bad for the heli / its crew?
The only way I see to avoid this would be to beam up the energy from somewhere other than at the anchor point. And that would have to substantially increase the difficulty of targeting the platform, since the distance between platform and beam source will increased if you move the beam source away from the anchor.
I suppose for actual "space elevator" applications the same thing will apply, only you'll be irradiating the floating counterweight or whatnot, and the destination.
Re:shouldn't they be able to design the cable also (Score:1, Insightful)
Two different fields:
climber: electrical/mechanical/controls engineering
cabel: material scientist
Not many people are both.
Re:Professor Myrabo at RPI (Score:4, Insightful)
Well, they're basing the tests on a helicopter, so the beam is relatively small. So for the test, they could easily beam the power from somewhere other than the anchor point. Having the beam come from a different direction wouldn't invalidate the important concept of "can beam power from ground to power the platform".
Not to mention, this test is based on a laser capable of delivering 400 watts of power to the target using infrared. Your average aluminum helicopter skin isn't going to vaporize under those conditions. Heck, I doubt you'd even scorch the paint.
In the "real world" use of this, the suspension unit is going to be much further away and specifically designed with protective shielding. In fact, the endpoint might have solar panels pointed back to Earth so any "stray" IR could be caught and used at the station - though it's far more likely they'd have a solar panel up there, too, and beam IR down to the elevator once it reaches a certain point and the beam from Earth starts dissipating too much.
Re:shouldn't they be able to design the cable also (Score:5, Insightful)
Nobody is able to design the cable. We simply don't have the technology, which is why they're focusing on the climber instead.
This is a bit like having a contest to design a cool hat to be worn while using an anti-gravity belt. If someone wins the contest, then we are one step closer to being able to float while wearing a cool hat - all that's left is the bit with the belt.
Re:Good to hear. (Score:2, Insightful)
Re:shouldn't they be able to design the cable also (Score:1, Insightful)
Thank you. I just don't get the space elevator love on Slashdot.
I'm not impressed by a climb up a 1km strand of anything.
Build me a 1km suspension bridge with a mass limit of 100kg, and call me when someone's cute little robot can walk across it. Then I'll be impressed.
Space elevators are materials science problems, not robotics problems. The mass of the climber is negligible in comparison to the mass of the elevator. Stop dicking around with the robots and start building suspension bridges over college campus footpaths, using cables the width of a human hair.
Mod parent up. (Score:4, Insightful)
Re:Mod parent up. (Score:5, Insightful)
Let's say that at our current progress it would take us 30 years to develop a way to manufacture the cable. Then let's assume that it will take 15 years to develop a machine capable of climbing that cable.
Since the two technologies are completely distinct from each other (i.e. the solution will come from different industries) Doesn't it make sense to develop them in parallel rather than wait for the cable to be developed and then have to wait an additional 15 years for the climber technology to mature?
I've certainly polished my shoes while waiting for the limo to arrive. If the limo didn't arrive, it would have made the shoe polishing pointless, but I wouldn't want to pay for a limo to wait while I got ready.
Re:Mod parent up. (Score:3, Insightful)
I am going to go out a limb here and state that creating the cable is several orders of magnitudes harder than creating a machine to climb it. Maybe even an order of magnitude more orders of magnitude.
All these little contests do is try to generate support and interest in the space elevator concept. I don't think anything revolutionary will come out of them.
Its all about the cable.
Re:Are we serious? (Score:3, Insightful)
The key word that's part of ICBM is "ballistic", from the Greek ballein, I throw. It's travelling through extremely thin gas, and its trajectory is therefore practically simple Newtonian dynamics. Its position from moment to moment should be extremely predictable.
In theory, yes. In practice, it's going to depend on how accurately you can measure its position and velocity at any given moment. The missile is moving very rapidly relative to the target size it presents, so small errors in measuring its position will result in larger errors in the extrapolated arc and could easily result in a miss. Also, since Star Wars none of the anti-ICBM techniques have focused on the peak of its trajectory where it is a purely Newtonian ballistic projectile. They either target the lift phase where it is most decidedly not ballistic, or the descent phase where air resistance cannot be ignored. The ones who designed and programmed the missile can't predict its trajectory to within one missile-width, so why assume it's easy for the defender to figure this out? It's not an easy problem at all, which is why the Missile Defense Shield has met with only limited (read: assisted) success.
Even worse would be to assume that technology is limited by the Latin roots of words used to describe it. "Ballistic" already applies to only a portion of the flight, and as Russia was quite keen to point out during the height of the MDS push their missiles have descent phase countermeasures like, um, dodging.
So think of it more like hitting an unconscious fly that is traveling as fast as a fastball, could at any moment wake up and start flapping, and you aren't trying to catch it in a glove, you're trying to spear it with a toothpick before it gets too close.
Solvable? Oh sure probably for any given iteration of the enemy's missile. Obviously easier than hitting a relatively slow-moving target that wants to be hit and thus can be broadcasting its position (like the test missiles did in the descent-phase anti-missile tests)? Yeah I'm not so sure about that.
The problem is, I'm sure, soluble, but the technical difficulty should not be underestimated.
No, its certainly not an easy task. I just think hitting a missile that doesn't want to be hit is comparable if not harder to achieve (because while the missile will be modified to make it harder to hit, the elevator will be modified to make it easier).
Re:Mod parent up. (Score:2, Insightful)
Meh. Laser propulsion likely has other uses if we develop it to the point where it's useful for space elevators.
Re:Professor Myrabo at RPI (Score:3, Insightful)
Re:shouldn't they be able to design the cable also (Score:4, Insightful)
In addition, a moon space elevator will not have a number of the serious problems that an earth space elevator would have, in particular flying space junk (though there is some around the moon at this point), hurricane force winds, and terrorists. Don't think for a minute that a space elevator is not a juicy target for some pissed off group that knows how to fly planes.