Inside America's U-2 Spyplane [video] • Hacker News Board

Re: Inside America's U-2 Spyplane [video]

#31

Post by libertyhouse » Mon, Jun 11, 2018, 2:20 AM UTC

bduerst wrote: post #24

philip1209 wrote: post #2

The details about the camera equipment seems to be newly declassified. Super interesting.

The U2 pilots typically don't even know what sensor equipment they're using either - it's all super hush-hush. They basically go up, fly their routes, and land without knowing what's going on underneath.

No - that's not true. Pilots are fully aware of the sensor configuration. There are a number of sensor controls and circuit breakers in the cockpit that are checklist and operator items. Pilots must be able to help troubleshoot some types of sensor failures.

The pilots don't usually see raw product because it's really not in their lane - but they are the aircraft commander and pretty much know quite a bit of detail about stuff mounted to the aircraft.

Re: Inside America's U-2 Spyplane [video]

#32

Post by libertyhouse » Mon, Jun 11, 2018, 2:23 AM UTC

nyolfen wrote: post #14

if you're interested in the mechanics of flying a u-2 and the protocols usaf pilots used (at least in the 50s and 60s), i transcribed a series of letters my grandfather wrote about it after his career ended. https://hyperstition.al/u2-james-black/

Fantastic transcription - really interesting! These early U-2 pilots had a lot of courage and love for flying.

Thank You for posting this.

Re: Inside America's U-2 Spyplane [video]

#33

Post by nyolfen » Mon, Jun 11, 2018, 3:57 AM UTC

privong wrote: post #29

nyolfen wrote: post #14

if you're interested in the mechanics of flying a u-2 and the protocols usaf pilots used (at least in the 50s and 60s), i transcribed a series of letters my grandfather wrote about it after his career ended. https://hyperstition.al/u2-james-black/

Very interesting, thanks for posting the link. I saw a minor typo, but couldn't find an email address for you, so posting here in the hope you see it. In the first paragraph of the addendum you have an "Out contact" that should be "Our contact".

appreciated!

Re: Inside America's U-2 Spyplane [video]

#34

Post by nyolfen » Mon, Jun 11, 2018, 3:57 AM UTC

ethbro wrote: post #30

nyolfen wrote: post #14

if you're interested in the mechanics of flying a u-2 and the protocols usaf pilots used (at least in the 50s and 60s), i transcribed a series of letters my grandfather wrote about it after his career ended. https://hyperstition.al/u2-james-black/

In the spirit of "thanks so much for recording this, but minor edits", assuming the below should be "every". "From there you reduced the indicated by 2.5K for over one-thousand feet"

thank you!

Re: Inside America's U-2 Spyplane [video]

#35

Post by lb1lf » Mon, Jun 11, 2018, 1:48 PM UTC

libertyhouse wrote: post #28

lb1lf wrote: post #13

Earlier quoted context omitted.

When what you’re after is very high resolution, film still scales better than digital; the largest (somewhat common) film format is 8x10». A sheet of slow (fine grain) film at this size can capture detail way beyond what any digital sensor I know of - surely it can be scanned with the equivalent of multi-gigapixel resolution - and if one were to develop such a monster sensor, it would have a hard time competing with…

Film alone doesn't determine performance - the whole instrument must be considered. The OBC trades "resolution" for area coverage rate. The digital electro-optical imagery from the U-2 is produced using an instrument (SYERS-2) with a different optical design. Intelligence Imagery (IMINT) is rated on the NIIRS scale and the OBC imagery is most-likely unclassified now due to it being at the mid-range of the NIIRS scale…

-Film definitely is only part of the equation, and I have to admit I have no idea how optics scale (that is - is it easier or harder to make a lens with a large image circle with excellent resolving power, as opposed to a smaller image circle?)

My (attempted!) point was that fine-grain film* creates a negative which will be a challenge to match for most sensors out there - it is my understanding sensor yield drops drastically as it increases in size, so if you need a huge sensor, film is still the most cost-effective solution for a lot of applications. Then again, 'cost-effective' and 'national security' are two phrases which do not often come up in the same sentence!

*) My favourite - ADOX CMS20, has a resolving power which easily outperforms even a Summicron 50 at a sensible (not diffraction-restricted) aperture - more than 500lp/mm; the manufacturer claim up to 800lp/mm are resolvable (!)

That translates into some 12,500 line pairs/inch of film/sensor, as long as the optics are holding up their part of the bargain - or somewhere just short of 1 gigapixel from a 24x36mm frame, if scanned using -cough- sufficiently expensive equipment.