IPB

Welcome Guest ( Log In | Register )

30 Pages V  « < 27 28 29 30 >  
Reply to this topicStart new topic
Apollo Sites from LRO
James Fincannon
post Apr 5 2017, 03:45 PM
Post #421


Junior Member
**

Group: Members
Posts: 59
Joined: 30-July 09
Member No.: 4887



QUOTE (algorimancer @ Apr 4 2017, 06:18 PM) *
Neat. What's the scale on these?



The length of the long object is 64 m. The shorter is 40 m. They are about 15 m wide
Go to the top of the page
 
+Quote Post
Ian R
post Apr 5 2017, 06:44 PM
Post #422


Member
***

Group: Members
Posts: 757
Joined: 18-July 05
From: Plymouth, UK
Member No.: 437



The impact crater caused by the Surveyor 3 retrorocket was fortuitously photographed during the Apollo 12 landing:

http://www.unmannedspaceflight.com/index.p...st&p=226887


--------------------
Go to the top of the page
 
+Quote Post
GoneToPlaid
post Apr 5 2017, 06:51 PM
Post #423


Newbie
*

Group: Members
Posts: 15
Joined: 24-February 17
From: California
Member No.: 8127



QUOTE (James Fincannon @ Apr 5 2017, 07:06 AM) *
Hello GoneToPlaid! Good to hear from you!

Thanks for your desire to credit me with finding this peculiar feature, however, I must correct the record in that I merely heard about it on some podcast and then googled it to find that others have investigated it (Google pointe dme to someplace called the Lunascan project). I realized that the Unmanned Spaceflight forum has a high level of lunar expertise so was hoping to obtain some scientific conjecture on the blocks. I can say I was not disappointed.

However, even with the conjectures presented here so far (although they are interesting and educational), I still am not completely convinced due to the one-off nature of the blocks. This is like Tabby's Star in a way. If we could find others that are just like it, it would help a lot in explaining it definitively.


Hi James,

Actually, there is a similar feature which are seen in the crater Obama (adjacent to Ina), and which is seen at other IMPs. So your identified feature is not a "one-off" feature which is seen on the moon.

Best regards,

--GoneToPlaid
Go to the top of the page
 
+Quote Post
James Fincannon
post Apr 5 2017, 07:37 PM
Post #424


Junior Member
**

Group: Members
Posts: 59
Joined: 30-July 09
Member No.: 4887



QUOTE (GoneToPlaid @ Apr 5 2017, 07:51 PM) *
Hi James,

Actually, there is a similar feature which are seen in the crater Obama (adjacent to Ina), and which is seen at other IMPs. So your identified feature is not a "one-off" feature which is seen on the moon.

Best regards,

--GoneToPlaid



Hello GoneToPlaid,

You mean Crater Osama (not Obama wink.gif right? http://bit.ly/2o4h6QA

There are lots of places on the Moon that have obvious boulders or rocks that are shed (and I really think Ina features are great, by the way!). But the problem is that they are obvious. Same for the boulder tracks. You can see that the boulders rolled from the top of the crater to the floor, regardless of whether they bounced, skipped, slid, wobbled or just plain rolled.

What I would like to see is more such blocks with no apparent origin. Something like this http://bit.ly/2o4osUg in Crater Vertregt K, although it is not quire "there" yet.



Go to the top of the page
 
+Quote Post
GoneToPlaid
post Apr 5 2017, 08:14 PM
Post #425


Newbie
*

Group: Members
Posts: 15
Joined: 24-February 17
From: California
Member No.: 8127



QUOTE (James Fincannon @ Apr 5 2017, 12:37 PM) *
Hello GoneToPlaid,

You mean Crater Osama (not Obama wink.gif right? http://bit.ly/2o4h6QA

There are lots of places on the Moon that have obvious boulders or rocks that are shed (and I really think Ina features are great, by the way!). But the problem is that they are obvious. Same for the boulder tracks. You can see that the boulders rolled from the top of the crater to the floor, regardless of whether they bounced, skipped, slid, wobbled or just plain rolled.

What I would like to see is more such blocks with no apparent origin. Something like this http://bit.ly/2o4osUg in Crater Vertregt K, although it is not quire "there" yet.


Oops! Yes, I meant to say Osama.
Go to the top of the page
 
+Quote Post
Phil Stooke
post Apr 8 2017, 05:58 PM
Post #426


Martian Cartographer
****

Group: Members
Posts: 7310
Joined: 5-April 05
From: Canada
Member No.: 227



Hi James - you did that amazing work a while ago (2011) on showing that most of the Apollo flags were still upright. In particular, at Apollo 14, you had noted in 2012 that its shadow could not be seen:

https://www.hq.nasa.gov/alsj/a14/a14FlagDeployment.html


I wondered if you had revisited the LROC images since then, since we have more views now.

I just looked at a sequence of images and I see that the Apollo 14 flag shadow is in fact clearly visible. With hindsight I can now see it in your sequence at that link.

Here's a set of stills with the flag and MET shadows indicated.

Phil

Attached Image


--------------------
... because the Solar System ain't gonna map itself.
Go to the top of the page
 
+Quote Post
bkellysky
post Apr 8 2017, 07:32 PM
Post #427


Junior Member
**

Group: Members
Posts: 81
Joined: 25-April 08
From: near New York City, NY
Member No.: 4103



Can I just say how fantastic it is to be able to see if the flags are still up at the Apollo landing sites? Thank you LRO! Thank you, picture processors, for picking out the shadows of the flags!
What does this mean for the hardiness of the flag materials? I seem to remember they were likely to disintegrate by now.
bob
Go to the top of the page
 
+Quote Post
Phil Stooke
post Apr 8 2017, 08:26 PM
Post #428


Martian Cartographer
****

Group: Members
Posts: 7310
Joined: 5-April 05
From: Canada
Member No.: 227



Some people have suggested the flags would have disintegrated under solar UV and other environmental factors. I think the current view is that the degradation observed on Earth is accelerated by the presence of oxygen in the air, and it seems the flags are mostly intact on the Moon at present.

Phil


--------------------
... because the Solar System ain't gonna map itself.
Go to the top of the page
 
+Quote Post
Explorer1
post Apr 8 2017, 11:57 PM
Post #429


Senior Member
****

Group: Members
Posts: 1455
Joined: 13-February 10
From: Ontario
Member No.: 5221



I read somewhere that the colours would gradually be lost, due to the radiation, and they'd have lost their patterns and turned white by now? I suppose that's more of a material chemistry question; the only way to find out for sure is a followup landing...
Go to the top of the page
 
+Quote Post
stevesliva
post Apr 9 2017, 03:17 AM
Post #430


Senior Member
****

Group: Members
Posts: 1329
Joined: 14-October 05
From: Vermont
Member No.: 530



QUOTE (Phil Stooke @ Apr 8 2017, 03:26 PM) *
Some people have suggested the flags would have disintegrated under solar UV and other environmental factors. I think the current view is that the degradation observed on Earth is accelerated by the presence of oxygen in the air, and it seems the flags are mostly intact on the Moon at present.


"We" may have established that view 7 1/2 years ago in this thread.

Post 87 links to an Air & Space article where the flag's manufacturer concludes that a 39 year-old nylon flag on earth would be in rough shape, certainly the ones on the moon were "dust" or "bleached" as suggested by the article's author. Mcaplinger was immediately skeptical.

Then around post 322 the topic came up again and some armchair chemist named stevesliva appealed to the authority of http://en.wikipedia.org/wiki/UV_degradation ...

So yeah, grain of salt either way. They certainly appear to be there, still!
Go to the top of the page
 
+Quote Post
GoneToPlaid
post Apr 9 2017, 09:13 PM
Post #431


Newbie
*

Group: Members
Posts: 15
Joined: 24-February 17
From: California
Member No.: 8127



QUOTE (Explorer1 @ Apr 8 2017, 04:57 PM) *
I read somewhere that the colours would gradually be lost, due to the radiation, and they'd have lost their patterns and turned white by now? I suppose that's more of a material chemistry question; the only way to find out for sure is a followup landing...


All of the flags (except for Apollo 11 which was blown down on LM liftoff) are casting very dark shadows. One might assume that even if most of the colors have faded away, the flags could still cast dark shadows with mid morning or mid afternoon sunlight at the landing sites. Yet interestingly, all of the flags cast very dark shadows even with the sun very low above the east or west horizon in which the sunlight is striking the flags as face-on as possible. This seems to imply that the flags are still quite opaque. For example, the A12 flag's shadow at sunrise or sunset is noticeably darker than the high gain antenna shadow, yet not as dark as the LM descent stage shadow.
Go to the top of the page
 
+Quote Post
James Fincannon
post Apr 10 2017, 04:42 PM
Post #432


Junior Member
**

Group: Members
Posts: 59
Joined: 30-July 09
Member No.: 4887



QUOTE (Phil Stooke @ Apr 8 2017, 06:58 PM) *
Hi James - you did that amazing work a while ago (2011) on showing that most of the Apollo flags were still upright. In particular, at Apollo 14, you had noted in 2012 that its shadow could not be seen:

https://www.hq.nasa.gov/alsj/a14/a14FlagDeployment.html

I wondered if you had revisited the LROC images since then, since we have more views now.

I just looked at a sequence of images and I see that the Apollo 14 flag shadow is in fact clearly visible. With hindsight I can now see it in your sequence at that link.


I do not understand how you can see it is "clearly visible". For one thing, do we know where the antenna is? Is it on its side to cast a thick shadow or what?

I would need to calculate the length of the flag shadow (not including the pole) for the shallowest sun elevation images to confirm this is likely a flag shadow. It did not jump out at me at the time as being obvious, but maybe I was wrong.
Go to the top of the page
 
+Quote Post
Phil Stooke
post Apr 10 2017, 05:01 PM
Post #433


Martian Cartographer
****

Group: Members
Posts: 7310
Joined: 5-April 05
From: Canada
Member No.: 227



I didn't mention the antenna, but this is my interpretation of what we see:

Attached Image


In the sequence I posted, let me point out the 4th frame down which, uniquely among them, shows a bright linear glint. I interpret it as a reflection off one of the antenna legs, which in one frame is perfectly placed to give a strong reflection. We see similar things with ALSEP cables etc, showing bright in the occasional image and not in others.

But we know where the flag was placed and we see it relative to the MET in images from the LM window. Its shadow would be very slightly north of the MET shadow. In my sequence it clearly progresses with the lighting just like all the other shadows. And your sequence from the ALSJ page has it faintly visible as well.

Of course, you are right, its geometry should be calculated.

In my site map I show a 'dark spot'. I am having trouble figuring out what it is. We have good images of the area from the LM window and nothing obvious shows up.

Phil


--------------------
... because the Solar System ain't gonna map itself.
Go to the top of the page
 
+Quote Post
GoneToPlaid
post Apr 11 2017, 05:31 AM
Post #434


Newbie
*

Group: Members
Posts: 15
Joined: 24-February 17
From: California
Member No.: 8127



Hi everyone,

The LRO Team has posted sunrise to sunset "flip books", using actual LRO images, for each of the landing sites. They got the idea from one of my YouTube videos (no longer available since I closed that particular YT account) in which I animated LRO images of the Apollo 11 landing site to show the landing site from lunar sunrise to sunset. You all can check out the LRO Team's landing site sunrise to sunset flip books for each landing site here:

http://lroc.sese.asu.edu/featured_sites#ApolloLandingSites

It is a riot of fun to slide the slider back and forth to see all of the shadows of the Apollo mission artifacts, including the flag shadows move back and forth. Just as interesting is to see the glints off of some objects such as the LM footpads and lunar experiments which become strongly visible for given combinations of solar incidence and emission angles, yet which are not readily visible at other combinations of solar incidence and emission angles. The solar incidence angle is the elevation of the sun, relative to the zenith in the image, at the time when a given LRO image was acquired. Similarly, the solar emission angle is the angle towards the LRO camera, relative to the zenith in the image. You will see glints off of artifacts which do not correspond to any of the Apollo hardware, including the known locations of discarded covers and parts and tools. You might wonder what is the source of these extremely strong yet virtually pinpoint glints. These glints are from Kapton film which was blown off of the LM descent stages during the first second or two when each LM ascent stage lifted off from the lunar surface.

Finally, note that the LRO Team has resampled each image to an image scale of 0.5 meters which is the LRO Narrow Angle (NAC) camera's designed and theoretical resolution for the mission's Science phase orbital altitude of 50km. I normally present my deconvolved and enhanced LRO images at an image scale of 0.25 meters since under ideal conditions, very high contrast objects relative to the surrounding lunar terrain can be deconvolved to a lower limiting resolution. During the LRO's Science and Extended Mission phases, the LRO did for periods of time alter its orbit into low and very low periapse orbits in order to obtain higher resolution images of the Apollo landing sites. These orbits were highly unstable and could only be done for limited periods of time. After image deconvolution of images which were obtained during these lower LRO orbital altitudes, I generally present these images at an image scale of 0.125 meters, and sometimes at even smaller image scales, as shown below.

Below is the LRO Team's very low periapse image of the Apollo 11 landing site (left) versus my deconvolved and enhanced version (right) of the same image. The LRO'a orbital altitude was 24km. The image is M175124932R which was taken on 2011-11-05 (UT with Y-M-D nomenclature):

Attached Image


Best regards to all,

--GTP
Go to the top of the page
 
+Quote Post
GoneToPlaid
post Apr 19 2017, 03:23 PM
Post #435


Newbie
*

Group: Members
Posts: 15
Joined: 24-February 17
From: California
Member No.: 8127



QUOTE (gwiz @ Apr 5 2017, 02:51 AM) *


...but rather more battered.


How big is the retro rocket?
Go to the top of the page
 
+Quote Post

30 Pages V  « < 27 28 29 30 >
Reply to this topicStart new topic

 



RSS Lo-Fi Version Time is now: 22nd November 2017 - 11:21 AM
RULES AND GUIDELINES
Please read the Forum Rules and Guidelines before posting.

IMAGE COPYRIGHT
Images posted on UnmannedSpaceflight.com may be copyrighted. Do not reproduce without permission. Read here for further information on space images and copyright.

OPINIONS AND MODERATION
Opinions expressed on UnmannedSpaceflight.com are those of the individual posters and do not necessarily reflect the opinions of UnmannedSpaceflight.com or The Planetary Society. The all-volunteer UnmannedSpaceflight.com moderation team is wholly independent of The Planetary Society. The Planetary Society has no influence over decisions made by the UnmannedSpaceflight.com moderators.
SUPPORT THE FORUM
Unmannedspaceflight.com is a project of the Planetary Society and is funded by donations from visitors and members. Help keep this forum up and running by contributing here.