'Undesterbed' soil and Antenna dimensions.

[raven]

Hello, I have two questions, one I know I partially answered, but can't find the rest of the data, and the other I posited, but this not being my area of expertise, decided to ask what you people thought of my answer.
Item one: I was answering a query on the 'disappearing' antenna, and I responded the blade antenna would be more or less visible depending on angle. They accepted this as a good explanation, wonder of wonders, but asked it's exact dimensions. Now, I enjoy a good Googling, but I could only find one of the dimensions.
According to this paper paper on page four it was about 10.25 inches long, but no mention of the width nor thickness is made. An answer, and a source I can link to if possible, would be greatly appreciated.

Item the second: They also asked about the lack of rover tracks in several rover Hasselblad photos. I myself have seen this ,and I explained that the work of the astronauts would obscure tracks. They agreed this would do some obscuring, that the surface underneath the rover, inaccessible to working astronauts, often appears 'pristine' as well.
After some thought, I posited that the dust brought forward by the back mesh wheels, as well as that kicked back by the front, would obscure the track of the front wheel underneath the rover. To show it in action, I linked to 16mm footage of the Apollo 16 'test drive'.
It makes sense to me, but this isn't my area of expertise.
What do the other members of this fine community think?

Well, any answers would be appreciated,and I thank your dearly for them.
Happy posting!

[Jason Thompson]

Sounds fine to me.

Blade antenna: one other thing to bear in mind is that one side is black while the other is silvered, which has a huge effect on its visibility.

Rover: There is plenty of space under the rover for dust kicked up by any of the wheels or the astronauts to get kicked over the tracks, even if they can't get their feet right under there, and the angle of lihting on the surface, as well as the surface itself, affects how much the tracks will be visible anyway.

The bigger question is what they propose was done instead. EVen if it was faked, they had a set and they had a rover with wheels, so what would make more sense than rolling it into place to make it look like it was driven there? Other methods such as lowering it into place, or dressing the set after it was placed, or pasting the picture in make no sense in terms of why those methods would be employed.

[dwight]

There is also the fact that on Apollo 15 after EVA 1, Jim Irwin's antenna broke as he returned into the LM. You won't see his antenna reflecting because of the manner in which Dave Scott fixed it.

www.workingonthemoon.com/WOTM-DuctTape.html

[cos]

Aside from dust being kicked up to obscure the tracks the visibility of the tracks in photographs very much depends on the relative sun angle, at certain inclinations the tracks are hard to spot.
Also the astronauts did on occasion physically pick up the car and move it. I recall Dave Scott doing so at the end of an EVA (3?) on Apollo 15 - Mission control wanted a particular shot from the car mounted camera and I imagine it was quicker to drag the vehicle around rather manoeuvre it. Try explaining the tracks from a subsequent still photo! - if any HB cares to sit through the 9 EVAs of Apollo 15, 16 & 17 they can make a note of when this occurs - they won't of course but if they did they wouldn't be HBs at the end of it!

[gillianren]

Don't we have an enormous and tedious thread about rover tracks?

[laurel]

Apr 21, 2010 9:51:35 GMT -4 cos said:

Also the astronauts did on occasion physically pick up the car and move it. I recall Dave Scott doing so at the end of an EVA (3?) on Apollo 15 - Mission control wanted a particular shot from the car mounted camera and I imagine it was quicker to drag the vehicle around rather manoeuvre it.

This might be what you're thinking of:

167:15:36 Irwin: Maybe you ought to lift up the front end of the Rover, so you're clearly visible.

167:15:40 Scott: That's a good idea. Let's just swing it around...Let me get this side here.

[Dave runs out to the CDR seat while Jim goes to the LMP seat. As shown in AS15-82- 11201, they each have a U-shaped handle on the outer edge of the chassis and, by gripping the handles can lift and re-position the Rover. The empty weight of the Rover is 462 terrestrial pounds (210 kg) and only 77 pounds (35 kg) on the Moon.]

167:15:45 Scott: Let's just swing it clockwise for about...Why don't you grab the handle over there and let's just swing it clockwise for about 15 (or) 20 degrees.

[raven]

Thanks, I'll have to show that to them, laurel. And thanks for the info on the antenna, Jason Thompson, but any info on its actual proportions?

[PeterB]

Apr 21, 2010 2:09:11 GMT -4 raven said:

According to this paper paper on page four it was about 10.25 inches long, but no mention of the width nor thickness is made.

I noticed that just below the mention of the antenna's length, it said the antenna was potted in a pot which had a 1.25 inch diameter. That indicates it couldn't have been any wider than that. Also, do you know that it was a curved strip of metal? That is, it looked a lot like a length of tape measure. The significance of that is that it would affect its angular width when seen from different directions.

tem the second: They also asked about the lack of rover tracks in several rover Hasselblad photos. I myself have seen this ,and I explained that the work of the astronauts would obscure tracks. They agreed this would do some obscuring, that the surface underneath the rover, inaccessible to working astronauts, often appears 'pristine' as well.

After some thought, I posited that the dust brought forward by the back mesh wheels, as well as that kicked back by the front, would obscure the track of the front wheel underneath the rover. To show it in action, I linked to 16mm footage of the Apollo 16 'test drive'.
It makes sense to me, but this isn't my area of expertise.
What do the other members of this fine community think?

Keep in mind that when the astronauts walked around, they didn't obscure tracks only where their feet landed. The act of walking on the Moon also involved kicking soil ahead of their feet, and this would help obscure tracks in places their feet wouldn't normally reach. This would be particularly the case around the rover - the astronauts would walk up to the rover and stop, and in the process kick soil ahead of them, onto the tracks between the wheels.

[grashtel]

Apr 21, 2010 2:09:11 GMT -4 raven said:

Item the second: They also asked about the lack of rover tracks in several rover Hasselblad photos. I myself have seen this ,and I explained that the work of the astronauts would obscure tracks. They agreed this would do some obscuring, that the surface underneath the rover, inaccessible to working astronauts, often appears 'pristine' as well.
After some thought, I posited that the dust brought forward by the back mesh wheels, as well as that kicked back by the front, would obscure the track of the front wheel underneath the rover. To show it in action, I linked to 16mm footage of the Apollo 16 'test drive'.
It makes sense to me, but this isn't my area of expertise.
What do the other members of this fine community think?

If you look closely at the left of AS15-88-11899 you will see that the rover tracks are often not very easily visible to begin with (IIRC this is due to the mesh tyres tending to drop dust back into the tracks) and how far the dust kicked up by the astronauts could travel in the one sixth gravity airless environment of the moon in sufficient quantities to obscure the tracks completely.

Another nice thing about that photo is that it is a part of a pan which contains one of the popular images (AS15-88-11901 to be exact) for HBs making the "no tracks" claim and that if you follow the pan around you can show of the tracks "mysteeriously" disappear as they get close to where the astronauts have been walking around.

[slang]

Apr 21, 2010 14:01:36 GMT -4 gillianren said:

Don't we have an enormous and tedious thread about rover tracks?

This one, I think. Rover Footage Filmed on Earth

[echnaton]

The rover had a reverse. So the photos could plausibly have been taken after backing the rover in place.

[JayUtah]

Apr 21, 2010 21:38:39 GMT -4 PeterB said:

...

I noticed that just below the mention of the antenna's length, it said the antenna was potted in a pot which had a 1.25 inch diameter. That indicates it couldn't have been any wider than that.

On the OPS I last saw it was about a thumb's width, so right around an inch. Thickness would be around 0.05 inch.

Also, do you know that it was a curved strip of metal? That is, it looked a lot like a length of tape measure.

Exactly, and for the same reason. The origin of the antenna was a particular model of handy-talkie (the SCR type, as I recall) in which the tape antenna could be stowed by winding it around the body of the device and securing it with a strap. When unstrapped, it would unwind and spring into the deployed position and remain there. This supposedly reduced antenna breakage. The same physical properties let a carpenter's metal tape wind around the spool in the case.

The Apollo EMU antenna was meant to be stowed under a flap on the OPS during ingress and egress.