“With a ninty-four-inch telescope in space, we’ll be able to see phenomenal detail on planets,” I remarked.
“Just think what you could do if you pointed it at the earth,” Greg said.
“Why bother? All the interesting things are in the sky. And anyway, the Space Telescope physically can’t point to the earth. Its sensors will burn out if you try.”
“What if someone made such a telescope and pointed it to the earth. What could you see?”
I fiddled a few numbers in my head. Say, three hundred miles up in orbit, a nintyfour-inch telescope. The wavelength of light is about four hundred nanometers.… “Oh, you could easily see detail of a couple feet across. The limit would be around a couple inches. Not quite good enough to recognize a face.”
Greg smiled and said nothing. It took a while, but it eventually sunk in: the astronomical Space Telescope wasn’t the only big telescope in orbit. Greg was probably talking about some spy satellite. The secret KH-11, most likely.
Hubble was fixed by the costar addition. I wonder if there's missions to fix keyhole we don't know about.
Seriously, Wikipedia lists 5 generations. https://en.wikipedia.org/wiki/KH-11_KENNEN 5+3+4+3+3 total launches.
It was never going to be a good book plot so I gave up on it. Unrealistic that they'd steal "everything" including the intentional mistake. The idea of a double agent plot where "their guy" was actually "our guy" who made sure they stole the entire lot including the intentional grinding error was, um, cringy. In defense of my bad novel plot, I was young at the time, and I've read worse books.
[1] https://en.wikipedia.org/wiki/2012_National_Reconnaissance_O...
[2] https://en.wikipedia.org/wiki/Nancy_Grace_Roman_Space_Telesc...
The fact that it was the same form factor is not an accident, as Hubble was sized to fit in the shuttle payload bay, which was itself sized based on keyhole.
[edit]
The lunar Orbiter used an adapted E-1 camera from SAMOS. The E-2 and (canceled) E-3 also used the semi-dry development process and photomultiplier readout method.
The idea makes sense to me, generally, in that film is high res, high speed, can have a fadt shutter. Given where digital computers & imaging were, the idea of turning digitization into a batch slow process decoupled from capture makes all the sense in the world.
Can't say about recon sats but there are two reasons:
a) you need things fast
b) you can't drop it - you are too far
As sibling points out Lunar Orbiter used this and IMMSMV - some Soviet space probes (Venus?) too.
> Scanners in the 60s?
In the late 60s - just fine. Don't forget, TV existed back then already.
E-1 SAMOS launched in 1960. I was wrong about it using a CCD though, it used a photomultiplier.
Some chipped paint meant that a critical distance was extended by the thickness of the paint layer.
At Earth to spy satellite distances, it's like 1/4" and probably below the resolution of the camera used at the time.