Author Topic: Lockheed Martin SPIDER optical system  (Read 5251 times)

Offline Nilof

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Re: Lockheed Martin SPIDER optical system
« Reply #20 on: 08/05/2017 02:07 PM »
Lockheed martin's release on their site:
http://news.lockheedmartin.com/2017-08-03-Lockheed-Martin-Closes-In-On-Shrinking-the-Telescope-Reveals-First-Images-from-Instrument-as-Thick-as-a-Pen-Cap

They also linked to some pictures taken with their array prototype:
« Last Edit: 08/05/2017 02:37 PM by Nilof »
For a variable Isp spacecraft running at constant power and constant acceleration, the mass ratio is linear in delta-v.   Δv = ve0(MR-1). Or equivalently: Δv = vef PMF. Also, this is energy-optimal for a fixed delta-v and mass ratio.

Offline Propylox

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Re: Lockheed Martin SPIDER optical system
« Reply #21 on: 08/05/2017 04:41 PM »
... The big deal is the system should be scalable and the PIC can be mass produced, in fact Vice President Biden was at the launching of a new lab and manufacturing facility for producing these photonic devices - Military Money big time! ;)
Yep, this is a DARPA program for UAV surveillance which is hoping to expand into orbital use.
My guess is that the aperture is similar to diffractive lenses, but using interferometry to fold it up so that the depth isn't to big. I don't think it is designed to work at more than one wavelength, and it likely has significant drawbacks compared to regular optics. ...
They intend to combine many low resolution images in post processing to a single high resolution image?  I have my doubts that will work.
It's not in post processing, it's with interferometry. They combine light waves (phase and amplitude), not just images (amplitude only). That's why it can work.
Definitely going to need post-processing based on those diffracted results (note: as a DARPA program we can only be sure those are not their current results). These images appear to confirm Nilof's concern of interferometry's single wavelength sensitivity (likely IR for military applications) and others' resolution concerns.
« Last Edit: 08/05/2017 04:46 PM by Propylox »

Offline edzieba

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Re: Lockheed Martin SPIDER optical system
« Reply #22 on: 08/08/2017 05:17 PM »
It's an interesting device, kind of a hybrid between a Lightfield imager and a Phased Array imager (the current line array prototype is a Synthetic Aperture imager in the traditional sense due to being physically scanned). Each lens element is not independent so it's not a Lightfield imager, instead combining multiple lens elements into a single sensor with a known phase relationship using the PIC. But those monolithic arrays then need to be combined to create any appreciable aperture, and fabbing a really big PIC is going to be technically infeasible, so it makes sense to instead combine multiple of these arrays into a larger imager. Combining those blocks is likely going to need the same techniques as combining imaging elements as a Lightfield.
I wonder if they're using Telecentric lenses for the individual elements? If so, the whole array could be thought of as a big Telecentric lens making combination trivial, but losing most/all the computational imaging benefits and limiting you to only contiguous planar arrays.

Amusingly, the current rotating-line-array imager is a bit like the old TOSCA imaging idea for turning a spinning-mirror conical scan seeker head into an imaging seeker head without that pesky expensive focal plane array. Except now the array is cheaper than all those pesky optical gubbins you need to slap on the front!

Offline Propylox

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Re: Lockheed Martin SPIDER optical system
« Reply #23 on: 08/10/2017 02:27 AM »
Phone cameras are about to get a lot better  :)
Low resolution black-n-white isn't an improvement and SPIDER doesn't gather more photons per area than a traditional lens to shrink a camera. As described, it'd make every camera or telescope ever used worse - including ones from a hundred years ago. What it has going for it is form factor. That's it.