NASA's LRO Finds Photo Op as It Zips Past SKorea's Danuri Moon Orbiter | Hacker News Reader

NASA's LRO Finds Photo Op as It Zips Past SKorea's Danuri Moon Orbiter

nasa.gov

66 pointswawayanda12 comments

"about 7,200 miles, or 1,500 kilometers, per hour"

Sad to see that on the real NASA website. I'm guessing the 7200 miles is correct, and they typoed 11,500km. It just jumped out as so obviously wrong as I skimmed it.

And this is a reminder of what happened to that lost Mars probe

I have contacted NASA about this mistake.

They fixed it.

A 300uS shutter speed seems pretty high for a space based ground imaging camera. Does the LRO actually need a shutter speed that high? I'm surprised it's even capable of that.

This article details why they require such a resolution (1). The first few paragraphs talk about elevation, but then they dive onto the topic

(1) https://www.lroc.asu.edu/images/379

Would it be possible to simply tilt the camera at the same apparent rate as the ground is moving?

edit: Found that the Apollo panoramic camera used physical motion to balance the apparent motion of their target,

https://www.nasa.gov/history/afj/simbaycam/itek-pan-camera.h... ("The ITEK Panoramic Camera")

- "(2) the gimbal structure assembly, which rocks the roll frame assembly back and forth to provide for the stereo photography and to compensate for the forward motion of the vehicle,"

> Would it be possible to simply tilt the camera at the same apparent rate as the ground is moving?

Perhaps possible, but would it be lighter, more robust, or cheaper? My understanding is that solid state things are generally much more robust, and in these days of microchips, usually easier to implement.

Well, most consumer cameras are capable of 250μs shutter speeds, and prosumer cameras faster than that. And they're not zipping around their subject at several km/s.

This is wild. Is this the first time such a fly by between two orbiting probes been captured on camera?

No. The Mars Global Surveyor took a picture of the Mars Odyssey spacecraft in 2005. https://photojournal.jpl.nasa.gov/catalog/PIA07941

Closer to home, this is done somewhat often. https://www.twz.com/check-out-these-images-of-a-satellite-in...

Also, recently South Korea's orbiter got shots of Apollo 11 and 17 landing sites:

https://universemagazine.com/en/south-korean-spacecraft-phot...

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