Hires oblique views of Apollo landing sites from lunar orbit, Technically possible? Options

[Paolo Amoroso]

Given the emotional interest in closeup views of Apollo landing sites, and the debate on the preservation of historical lunar sites, I was wondering whether technological advances may reduce the need for rovers or other vehicles coming too close to the sites to get such views.

Given the resolving power of LRO's LROC camera, I expect technology to improve and provide even better resolution in a relatively short time. With such powerful cameras, would it be possible to get oblique views of Apollo sites from lunar orbit approximating the ones from a rover or a vehicle close to the sites? What are the major challenges? Spacecraft attitude control and camera pointing? Horizon curvature? Mountains, local relief and other obstacles along the line of sight?

This would not address, however, the need to come close for engineering studies or other purposes.


Paolo Amoroso

[ilbasso]

...

Given the resolving power of LRO's LROC camera, I expect technology to improve and provide even better resolution in a relatively short time. With such powerful cameras, would it be possible to get oblique views of Apollo sites from lunar orbit approximating the ones from a rover or a vehicle close to the sites? What are the major challenges? Spacecraft attitude control and camera pointing? Horizon curvature? Mountains, local relief and other obstacles along the line of sight?

I may have missed it in scanning the LRO thread, but has anyone done a simulated view of what an Apollo landing site would theoretically look like with LRO's highest-resolution camera, like Doug did for the Mars landers as potentially seen from MRO and MGS?

[tedstryk]

I may have missed it in scanning the LRO thread, but has anyone done a simulated view of what an Apollo landing site would theoretically look like with LRO's highest-resolution camera, like Doug did for the Mars landers as potentially seen from MRO and MGS?

I would think we probably already have really good views from the Lunar Orbiters and the Apollo missions, sans the landers, so this should make for some great before/after.

[nprev]

What are the major challenges? Spacecraft attitude control and camera pointing? Horizon curvature? Mountains, local relief and other obstacles along the line of sight?

Don't forget relative velocity to the lunar surface. With no effective atmosphere, you can go pretty low. That just might be the prime constraint/tradeoff on surface resolution: the higher you are, the slower you go, but you need bigger optics. If you go low, you need either a REALLY fast imaging system or an equally fast scan platform of some sort (brr...moving parts!), or fast-response attitude control & lots of fuel.

[edstrick]

If LRO can get really good matched image pairs of landing sites at different view angles and with matching illuminations (eg almost exactly one month apart...), the stereo data can be reprojected for any view angle, like Selene data.

[djellison]

To get an oblique angle, you end up much further away than your normal orbital altitude. 90k instead of 30k for example. So LRO's res of 50cm/pixel would drop to 1.5m/pixel.

Doug

[edstrick]

Either that, or you drop periapsis to shorten the slant-range for a given look angle...
"oops. I thought we'd miss that mountain".
Also, image smear gets to be a problem, and it gets really weird for non-framing cameras.

[kwan3217]

Don't forget relative velocity to the lunar surface. With no effective atmosphere, you can go pretty low. That just might be the prime constraint/tradeoff on surface resolution: the higher you are, the slower you go, but you need bigger optics. If you go low, you need either a REALLY fast imaging system or an equally fast scan platform of some sort (brr...moving parts!), or fast-response attitude control & lots of fuel.

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[dilo]

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[djellison]

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