Author Topic: Danuri/Korean Pathfinder Lunar Orbiter (Read 32483 times)

Blackstar · « **on:** 10/18/2021 04:12 pm »

https://www.leonarddavid.com/south-koreas-first-moon-mission/

This is a decent-sized spacecraft. Scheduled for August 2022 launch.

"Explains Mark Robinson, ShadowCam’s principal investigator at Arizona State University, the instrument is based on the successful Lunar Reconnaissance Orbiter Camera (LROC) Narrow Angle Camera (NAC) and will be over 100 times more sensitive (altitude dependent) than the current NAC."

edzieba · « **Reply #1 on:** 10/18/2021 04:36 pm »

ASU ShadowCam site: http://shadowcam.sese.asu.edu/about

Blackstar · « **Reply #2 on:** 10/19/2021 12:41 am »

Quote from: edzieba on 10/18/2021 04:36 pm

ASU ShadowCam site: http://shadowcam.sese.asu.edu/about

And by comparison, the LROC camera that it is derived from:

http://lroc.sese.asu.edu/about/specs

They both have the same focal length, although LROC has two narrow angle cameras compared to a single one on ShadowCam. However, I assume that the same focal length will provide the same ground resolved distance (resolution) on the lunar surface.

ccdengr · « **Reply #3 on:** 10/19/2021 01:16 am »

Quote from: Blackstar on 10/19/2021 12:41 am

However, I assume that the same focal length will provide the same ground resolved distance (resolution) on the lunar surface.

The sensor pitch is larger (12 microns as compared to 7 on LROC) so the resolution is lower by that ratio.

Phil Stooke · « **Reply #4 on:** 10/19/2021 07:03 am »

LRO takes those images of shaded areas at the very limit of what it can do, and the very weak signal is boosted by binning pixels (I forget the bin size right now) - so resolution in shaded areas is much poorer than the nominal 50 cm/pixel. Shadowcam should give much better signal at significantly higher resolution.

edzieba · « **Reply #5 on:** 10/19/2021 10:29 am »

Found a presentation on ShadowCam that highlights the major difference with the LROC's WAC: instead of the 1 x 5064 pixel line array, ShadowCam uses a 128 x 2916 pixel array, with TDI integrating between lines (as the array scans due to spacecraft movement, the lines are stepped in sequence to 'hover' a virtual line in place without smearing).

redliox · « **Reply #6 on:** 01/05/2022 06:50 pm »

Quote from: Blackstar on 10/19/2021 12:41 am

Quote from: edzieba on 10/18/2021 04:36 pm
ASU ShadowCam site: http://shadowcam.sese.asu.edu/about

And by comparison, the LROC camera that it is derived from:

http://lroc.sese.asu.edu/about/specs

They both have the same focal length, although LROC has two narrow angle cameras compared to a single one on ShadowCam. However, I assume that the same focal length will provide the same ground resolved distance (resolution) on the lunar surface.

It is excellent to see a new camera preparing to see the Moon. I keep forgetting how old LRO is, so anything with current technology will only improve what that craft has done. It will definitely be a great feather for Korea to put in it's spacefaring cap.

Tywin · « **Reply #7 on:** 08/05/2022 12:15 am »

https://twitter.com/CanberraDSN/status/1555344195795136512

Tywin · « **Reply #8 on:** 08/05/2022 01:31 am »

https://twitter.com/dirkpitt2050/status/1555360378770849792

Phil Stooke · « **Reply #9 on:** 08/05/2022 03:26 am »

In the headline story: "its orbit will have reached an apogee near the Earth/Moon Lagrange Point 1 (L1)."

But Jonathan McDowell tweets:

@planet4589
Danuri will head out to Sun-Earth Lagrange 1, and then fall back in towards the Moon, to enter lunar orbit. Similar approach to the CAPSTONE mission.
4:27 PM · Aug 4, 2022·

So, Earth-Moon or Sun-Earth?

gongora · « **Reply #10 on:** 08/05/2022 03:29 am »

Sun-Earth

Phil Stooke · « **Reply #11 on:** 08/05/2022 03:39 am »

Yes - I was just going to respond to my own post. Here:

https://www.kari.re.kr/eng/sub03_07_01.do

on the KARI website is an illustration of the path... it clearly shows the trajectory nearing Sun-Earth L1, but it is incorrectly labelled EM1.

The same source has an illustration of the approach to lunar orbit after the excursion to Sun-Earth L1. As it approaches the Moon it does a little jiggle around the Earth-Moon L2 point.