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29 votes

Could Hubble observe the night side of the Moon?

Hubble can in fact observe the Moon, and has done so. Here's a picture of the Apollo 17 site (The upper right is from Apollo 17 mission itself). The x shows where the actual site is. You can also see ...
PearsonArtPhoto's user avatar
  • 121k
15 votes
Accepted

The Moon's shadow could not possibly look like this — could it?

The deviations are real and directly related to the size of valleys on the Moon. The simple calculation you do here does only work for a point-like light source that projects the shape of the Moon ...
asdfex's user avatar
  • 15.1k
14 votes
Accepted

Crashed LMs visible on LRO images?

See this paper from P. J. Stooke, Department of Geography and Centre for Planetary Science and Exploration, University of Western Ontario, London, Ontario, Canada about the Apollo 12 and 14 impact ...
Uwe's user avatar
  • 49.2k
13 votes

Why was the 100m Green Bank dish needed together with DSN's 70m Goldstone dish to detect Chandrayaan-1 in lunar orbit?

The explanation has to do with the operation of the radar transmitters and the round trip light travel time. It takes about 3 seconds for a radar pulse to travel from the Earth to the Moon and back. ...
Joseph Lazio's user avatar
12 votes
Accepted

Are low, polar lunar orbits in general relatively stable?

LRO was inserted into a polar frozen orbit for commissioning, which required no stationkeeping. This orbit was a stable 31.5 km x 199 km polar orbit with periapsis over the South Pole. By "frozen" ...
Diane's user avatar
  • 674
7 votes

Why do the LRO's orbital elements appear to constantly oscillate - except recently?

JPL HORIZONS features orbits interpolated from actual data rather than pure simulations. I suspect that what happened here is that there is no orbital data for the three sections of data that don't ...
Schlusstein's user avatar
  • 2,157
7 votes

The Moon's shadow could not possibly look like this — could it?

I'll add this to the other answers, which do a very good job of explaining why this very irregular shape is not inconsistent with the Moon's original much "rounder" shape. This could be done with ...
uhoh's user avatar
  • 149k
5 votes

Could Hubble observe the night side of the Moon?

I believe COS (the sensitive UV instrument) could be damaged if it were pointed at the illuminated moon. (I wasn't able to find any documents online that confirm this though) The instruments don't ...
BowlOfRed's user avatar
  • 6,891
5 votes
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Why is the LROC lunar data not showing farside of the moon?

You have to select the correct projection to see the far side of the Moon: It is the top tab in the side bar.
BrendanLuke15's user avatar
4 votes
Accepted

How much does it cost to build terrestrial ground station capable of controlling satellites orbiting the moon?

With the data you provided is kind of hard to come up with a price tag. For a Ground Station you usually need the Antenna, Tx and Rx amplifiers, filters and other radio hardware, dedicated computing ...
Gabriel Sanchez's user avatar
4 votes

Why was the 100m Green Bank dish needed together with DSN's 70m Goldstone dish to detect Chandrayaan-1 in lunar orbit?

I know nothing of the activity you're asking about, but I do know something about radar. All the radar systems I've worked with used a single antenna to both transmit and receive. The power of the ...
Steve's user avatar
  • 1,174
4 votes

Mapping the moon: how to use the Lunar Reconnaissance Orbiter (LRO) image data?

tl;dr Those numbers are meters per pixel. But you have to be careful because they are scans along the spacecraft orbit with the moon rotating underneath, so x and y are skewed. This answer will get ...
uhoh's user avatar
  • 149k
4 votes

Why was the 100m Green Bank dish needed together with DSN's 70m Goldstone dish to detect Chandrayaan-1 in lunar orbit?

Since the deep space network can perform ranging on spacecraft much farther away (tens of thousands of times farther than the moon) by itself, why was it necessary to use a non-colocated, non-DSN dish ...
Hobbes's user avatar
  • 128k
4 votes
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The "live" 3D webpage showing LRO's activity is down, is this temporary?

I sent an email which started a chain (Jennifer Brill, John Keller, Emmanuel Dziwornooh). At some point during that, https://lrostk.gsfc.nasa.gov/ came back up. John Keller acknowledged that the site ...
foobarbecue's user avatar
  • 1,405
4 votes

The Moon's shadow could not possibly look like this — could it?

The outline of the lunar umbra on Earth (shadow of totality) will be defined by those rays of light emanating from the very edge of the solar disk as seen from Earth which just miss the surface ...
Anthony X's user avatar
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2 votes
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Why does LRO's laser altimeter telescopes use lenses instead of mirrors?

tl;dr: The 125 mm proven receiving telescope design used on the receiving telescope of the MLA laser ranger used on MESSENGER was adapted and enlarged to 150 mm for the LOLA of LRO. I am guessing that ...
uhoh's user avatar
  • 149k
2 votes

Was Chandrayaan-1 recovered (tracked) only that one time in 2016, or is someone still keeping an eye on it from time to time?

It was not "spotted just once". Rather, it was tracked until its orbital motion became predictable: On 2 July 2016, NASA used ground-based radar systems to relocate Chandrayaan-1 in its ...
Oscar Lanzi's user avatar
  • 8,525
2 votes

Lunar Reconnaissance Orbiter (LRO) stereographic projection transformation equations issues

I tried to do the same using python: ...
Uwe's user avatar
  • 49.2k
1 vote
Accepted

Can I retrieve longitude of Lunar Reconnaissance Orbiter around the Moon by POST method (URL)?

I had to set up a whole page to experiment with Horizons, and after weeks of testing I ended with this url, which you can see here exploded for better readability: ...
jumpjack's user avatar
  • 3,043
1 vote
Accepted

Could Hubble observe the night side of the Moon?

The pixel size of the HST's Wide Field Camera 3 or WFC-3 is 164/2048 = 0.08 arcsec. The night side of the Moon is illuminated by Earthshine and the brightness depends on the phase angle of the moon (...
uhoh's user avatar
  • 149k
1 vote
Accepted

Why do the LRO's orbital elements appear to constantly oscillate - except recently?

Based on some very helpful replies from Jon Giorgini at JPL and a bit of additional reading, I can summarize as follows: The actual calculation of spacecraft orbits, combining both the effects of ...
uhoh's user avatar
  • 149k
1 vote

Why was the 100m Green Bank dish needed together with DSN's 70m Goldstone dish to detect Chandrayaan-1 in lunar orbit?

This started out as a comment on one of the answers already provided, but it grew much too big to stay that way. There is good reason to collect and process bistatic ranging data even when there is no ...
Ryan C's user avatar
  • 7,972

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