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It's not often that I retweet the US president, but he tweeted this image of the Iranian Safir launch failure. The image is very interesting as evidence suggests that it was taken by a US spy satellite on August 29th, 2019. Here's my analysis.https://twitter.com/realDonaldTrump/status/1167493371973255170 …
The image shows the aftermath of an accident with an Iranian Safir rocket at the El Khomeini Spaceport. From the features of the launch pad, I find that the viewing directions of the camera match that of USA 224, a classified spy satellite.
There are 4 towers around the launch pad. Google Earth shows that the North and South towers are aligned along 192 deg azimuth. The camera azimuth is a further ~4 degrees West. From the elliptical shape of the circular launch pad, the elevation of the camera is around 46 degrees.pic.twitter.com/DRgKlanHWo
This is the path USA 224 followed across the sky from El Khomeini Spaceport on August 29, 2019. At 09:44:20, it passed very close to azimuth 196 deg and elevation 46 deg, matching the camera position. At that time, it was at a distance of 382 km.pic.twitter.com/bRgNhhC8lx
Since USA 224 is a classified satellite, orbital elements are not published by CSpOC. Fortunately, amateur satellite observers regularly track it across the sky, allowing its orbit to be determined. At the time of the image, the USA 224 orbit was last determined 2.4 days before.
It is not often that images from US Keyhole spy satellites are published. These satellites have 2.4m mirrors (as large as that of the Hubble telescope), and are believed to produce the sharpest images of the Earth's surface. The actual resolution of the images is kept secret.
Now that this image has been published, with the orbit of the satellite known, will enable some estimates of the resolution of the Keyhole satellites. Four of them are currently in orbit, USA 186, USA 224 , USA 245 and USA 290. See https://en.wikipedia.org/wiki/KH-11_Kennen … for more info.
My analysis of the USA 224 picture of the Safir launch failure (with python code), is available at https://github.com/cbassa/satellite_analysis/blob/master/nahid1_launch_failure_analysis.ipynb ….
Many thanks to @nukestrat, @DutchSpace and @trbrtc for pointing out that USA 224 might have taken the image. See also the independent analysis by @Marco_Langbroek at http://www.satobs.org/seesat/Aug-2019/0169.html …
Google Earth shows that the launch pad is about 60m in diameter, while the launch pad is about 600 pixels wide in the picture. That suggests a resolution of at least 10cm per pixel, as the original image could have had a higher resolution.pic.twitter.com/T7O76Mu5X4
This resolution is for a range of 382 km. The perigee of Keyhole satellites like USA 224 is around 260 km, so the theoretical resolution could be a factor 1.5 better.
One open question is whether USA 224 observed the El Khomeini Spaceport to track the Safir launch preparations, or to check the aftermath of the failure? Do we know when the failure happened? It must have been before 09:44UTC...
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