posted on Mar, 17 2006 @ 02:54 PM
iori_komei,
>>
The aircraft measures 78 cm (30 in.) long, weighs 800 grams (1.8 lbs.), and has wings like a kite. A disc-shaped solar panel attached underneath
powers the propeller when struck by a ground-based laser.
>>
Seems to me that the payload:weight fraction is going to be less than optimum for anything practical (long ranged relay or heavy optics). But as a
short range spydrone the implied low altitude mission capability seems optimal and the 'disaster monitoring' sweetheart mission nothing but a
cover.
Generally, /legitimate/ SAR type surveillance wants to be high up where it's viewed surface footprint lets it see junior standing on his '8 civvies
here' rooftop. As well as juniorette waving a hanky out a window 2 miles over.
Which means powerful optics and/or scanning LIDAR and a decent comms package to relay a fairly hefty bandwidth down to the 'rescuers'.
This system implies a capability to peep in people's windows. Listen to their cell phone and internet traffic and generally keep things covert (non
interfering with existing comms bands) by encoding datatraffic in the same beam as powers the drone itself. All from a van two blocks over.
Obviously, if someone can see the beam, they can probably see the drone or at least be aware of their presence but how many JQ Citizens have such an
IR-as-preference (eyesafe) option with civillian tech?
Enabling your government to spy on you with smaller and smaller toys that require less and less skilled interface usage seems quite dangerous IMO,
especially as the notion of sending out hordes of such devices and then powering them with a laser /miles away/, simply to avoid fuel starvation
problems 'in a disaster' setting is pushing the SOA for beam tracking and power loading towards weaponized energy levels as well.
>>
A battery powered the aircraft’s propeller at takeoff, but once it reached an altitude of about 50 meters (165 feet) — near the ceiling of the
dome — the aircraft switched to laser-powered flight. The laser remained on target (error less than 1 cm) throughout the 20-minute flight around the
dome. Observers say the aircraft looked like a kite flying on a string of light.
>>
As mentioned in the other poster's article, if the desire is to act as a pseudolite comms relay with HALE type area coverage, the question becomes
how far, through how much cloud and other anoprop, you can track the aircraft and power it.
Vs. how large a payload you're expecting to run. CommSats are not exactly featherweights you know.
Myself, while there is undoubtedly a night-side penalty to be considered for a more legitimate (full scale) system, it seems unlikely that a laser
could provide anywhere's near the flight PLUS transmission power levels that a UHF->low Microwave relay system would provide. And indeed, it _should
be simpler_ to use the microwaves themselves to enable direct conversion to auxilliary electrical power.
Rather than have the 'active solar' optical arrays function solely as electrical converters without any real volume or weight or placement
contribution to the mission package (as an antenna or whatever).
If it were me, I would go another way.
Say by enclosing the maximum possilbe volume you can get an effective wedge or blended wing:body aeroform to cover. Filling the whole body with
hydrogen or methane. Making collectors imbedded in the dorsal skins act as your primary flight system and possibly even an imbedded capacitor
charging array.
And suspend a folding microwave package below the resulting 'matress and bedsprings' type vehicle from a center keel.
Running the whole thing on solar during the day and hyper efficient hydrogen thermal batteries (at least enough to stay airborne) at night.
While beaming up MEP juice into a direct microwave:electrical conversion package to and thru the principle aperture array to sustain comms
networking.
Depending on the size of the platform and the local climatologics, it might even be possible to 'bleed down' (say from 60-80K to 20-40K) sieving
atmospheric moisture for hydrolitic conversion back to hydrogen the next day.
At the very least, you would have a 2-3 day cycle of endurance pseudolite relay before recovery and replacement of your 'super LEO' constellation
was required.
KPl.