IPB

Welcome Guest ( Log In | Register )

11 Pages V  < 1 2 3 4 5 > »   
Reply to this topicStart new topic
Soviet Luna Missions
4th rock from th...
post May 10 2006, 11:45 PM
Post #31


Member
***

Group: Members
Posts: 378
Joined: 21-April 05
From: Portugal
Member No.: 347



QUOTE (Phil Stooke @ May 7 2006, 09:19 PM) *
Here is a mosaic of Zond 3 images which I made a while ago. The early images over Oceanus Procelarum can't be fitted to the later ones. I apologise for the image size and quality, but I'm away from home and don't have my usual stuff with me.

Phil


Hi again wink.gif Here are my Zond 3 mosaics reduced in 50% size. Because of significant spacecraft movement it's only possible to join 3 or 4 images. 5 mosaics can be created this way using all the avaliable images.

Attached Image


If someone wants to go to trouble of reprojecting the images and assembling a complete mosaic I can provide the higher resolution originals. This wil be another of my ongoing projects...


--------------------
_______________________
www.astrosurf.com/nunes
Go to the top of the page
 
+Quote Post
Decepticon
post May 11 2006, 01:21 AM
Post #32


Senior Member
****

Group: Members
Posts: 1224
Joined: 25-November 04
Member No.: 114



Thanks so much for posting that!

I've been wanting to see these images for a long time.
Go to the top of the page
 
+Quote Post
edstrick
post May 11 2006, 09:41 AM
Post #33


Senior Member
****

Group: Members
Posts: 1869
Joined: 20-February 05
Member No.: 174



I've wanted to play with the Luna 3 images for years, but time, software availability (and time to learn to use it) and....

The original atlas of Luna 3 images had density sliced frames for some of the available images that could be histogram-matched and then merged into one dataset with extended dynamic range and less noise. The bigger part of the restoration would / should exist of removing or reducing periodic noise from the images with Fourier filtering: generate an image of just the periodic noise and subtract it from the raw image. Then further cleanup to remove noise-spike induced salt-and-pepper noise and readout and other artifacts.

Have at it!


The Zone 3 images could be mapped onto a sphere in something like 3 image sets and then registered and mosaiced.

I'd also *LOVE* to see a Zond 3 "movie".... Project each image on to the lunar sphere as viewed by Zond at the time of each image, then keeping the center of the sphere in the center of the frame and letting the sphere diameter vary as it did during the approach and flyby, make an animated gif / mov of the entire flyby with the frames displayed at proportional time intervals
Go to the top of the page
 
+Quote Post
4th rock from th...
post May 12 2006, 12:00 AM
Post #34


Member
***

Group: Members
Posts: 378
Joined: 21-April 05
From: Portugal
Member No.: 347



Attached Image


Just to see how much of the Moon was covered by the Zond images I made some crude reprojections to fill in the missing areas and came up with this. The image is as full resolution and a better result could be done with accurate reprojection and image averaging.


--------------------
_______________________
www.astrosurf.com/nunes
Go to the top of the page
 
+Quote Post
Guest_DonPMitchell_*
post May 15 2006, 04:48 AM
Post #35





Guests






Great Zond-3 mosaics!

To answer you question about Luna-3 transmision modes, the impression I have is that the early transmissions were very noisy, and they got higher quality pictures when the probe came back close to Earth. The images published in Lipsky's atlas are all slow-scan mode. The bands of static are periodic and consistant with the spin rate of Luna-3 (180 sec/rotation) after it finished photography and returned to spin-stabilized orientation. There was a dead spot in the radiation pattern of its antenna.

As far as I know, the only source of Luna-3 and Zond-3 images are prints of Lipsky's exposure-zone photos. I'm still trying to track down a real copy of the photos, and not a printed version. I just heard a few days ago that the Luna-3 magnetic tape is not located in the state archive institute, so we don't know where it is yet. My best guess now is that RNII KP has it.

I've gone off using the FFT method of descreening. What I do now is orient and resize the image so it is a 45 degree screen with exactly 5 pixels per vertical repeat. Then I filter it with a 5x5 custom box filter -- just go into the custom filter section of Photoshop and put a "1" in each box and set the weighting to 25. That box filter gives you a sinc function in the frequency domain, and it kills all the ink-dot harmonics completely. So much so, you can now sharpen the image as much as the noise level allows.

[attachment=5604:attachment] [attachment=5605:attachment] [attachment=5606:attachment]

For the rotation of the image, to make the screen 45 degrees, photoshop is fine. For the rescaling, I prefer to use the Lanczos-windowed sinc filter in ACDSee. There is a mistake in their filter that introduces a phase shift, but doesn't seem to bother too much (ACDSee is so buggy!). When I really care, I have a Kaiser-windowed sinc resampling routine I wrote in C++ that is rock solid.
Go to the top of the page
 
+Quote Post
Phil Stooke
post May 15 2006, 06:42 AM
Post #36


Solar System Cartographer
****

Group: Members
Posts: 8025
Joined: 5-April 05
From: Canada
Member No.: 227



4th Rock, I am very impressed with your Zond 3 mosaics.

Phil


--------------------
... because the Solar System ain't gonna map itself.
Go to the top of the page
 
+Quote Post
4th rock from th...
post May 15 2006, 04:02 PM
Post #37


Member
***

Group: Members
Posts: 378
Joined: 21-April 05
From: Portugal
Member No.: 347



Thanks all for the info and kind words!

I just found this on the internet: http://selena.sai.msu.ru

At least for me it's a new page!


--------------------
_______________________
www.astrosurf.com/nunes
Go to the top of the page
 
+Quote Post
Guest_DonPMitchell_*
post May 15 2006, 04:35 PM
Post #38





Guests






QUOTE (4th rock from the sun @ May 15 2006, 09:02 AM) *
Thanks all for the info and kind words!

I just found this on the internet: http://selena.sai.msu.ru

At least for me it's a new page!


Yeah, I got a few of my catalog images there, it's where Lipsky worked. I've had indirect dealings with them. Look at the Russian site, not the English versions. There's a nice set of reports on Luna probes here:Planetary Science and here:Luna Probes
Go to the top of the page
 
+Quote Post
Bob Shaw
post May 15 2006, 06:43 PM
Post #39


Senior Member
****

Group: Members
Posts: 2488
Joined: 17-April 05
From: Glasgow, Scotland, UK
Member No.: 239



Don:

Perhaps, in your researches into the Soviet moon probes, you've come across some details which might relate to a subject we previously discussed on here. Bruce Moomaw has managed to persuade us that the hard-landing Luna vehicles used some form of airbags during the landing sequence - an element of that process which was new to most of us! Although it's fairly obvious where the bags must have been (in a splittable 'sock' over the ball of the lander) there are still very few references to just *how* the darn things worked (or didn't).

Have you come across these air-bags, or a landing sequence which refers to them?

Bob Shaw


--------------------
Remember: Time Flies like the wind - but Fruit Flies like bananas!
Go to the top of the page
 
+Quote Post
tedstryk
post May 15 2006, 07:22 PM
Post #40


Interplanetary Dumpster Diver
****

Group: Moderator
Posts: 4393
Joined: 17-February 04
From: Powell, TN
Member No.: 33



QUOTE (Bob Shaw @ May 15 2006, 06:43 PM) *
Bruce Moomaw has managed to persuade us that the hard-landing Luna vehicles used some form of airbags during the landing sequence - an element of that process which was new to most of us! A
Have you come across these air-bags, or a landing sequence which refers to them?

Bob Shaw


This is correct:
"Luna 9 had a mass on release from the upper stage of 1602 kg. The KTDU main engine had a thrust of 4500 kgf and 847 kg of propellant was loaded. A total of 6 seconds of burn time was allocated for mid-course manoeuvres and 45 seconds for the lunar landing braking manoeuvre. After the braking manoeuvre, with the probe some distance over the lunar surface, the burn-out mass of the entire spacecraft was 430 kg. After the impact air bag had cushioned the final bouncing impact on the surface, the final mass of the probe on the surface was 79.5 kg The television camera aboard had a resolution of 15-20 mm on objects 2 m from the camera. Batteries provided power for five days of operation on the surface, with one hour of data transmissions back to earth per day."
http://www.astronautix.com/craft/lunae6.htm


--------------------
Go to the top of the page
 
+Quote Post
Bob Shaw
post May 15 2006, 08:49 PM
Post #41


Senior Member
****

Group: Members
Posts: 2488
Joined: 17-April 05
From: Glasgow, Scotland, UK
Member No.: 239



Interestingly, the Astronautix.com page has a picture of... ...landing bag tests!

So: what exactly happened to the landing bags after, er, landing?

Bob Shaw
Attached thumbnail(s)
Attached Image
 


--------------------
Remember: Time Flies like the wind - but Fruit Flies like bananas!
Go to the top of the page
 
+Quote Post
Guest_BruceMoomaw_*
post May 15 2006, 10:59 PM
Post #42





Guests






One of the cartoons we saw earlier (or at least I saw one, and I think it was on this site) showed the two of them simply being separated from the capsule after landing.

That series of photos of them actually being tested is a neat finding -- I hadn't heard anything about it.
Go to the top of the page
 
+Quote Post
Guest_DonPMitchell_*
post May 15 2006, 11:57 PM
Post #43





Guests






Yes indeed, the Soviets used airbags to land on the Moon. The main craft used an optical horizon and a radar altimeter to control its descent, with a retro rocket. The airbags were inflated, and when a long probe touched the Moon, the airbag was jetisoned. After it came to rest, pyrocharges blew the airbags away from the "automatic lunar station". If you look at the Luna-13 panoramas, you can see pieces of the spacecraft strewn about the landing site:

[attachment=5619:attachment] [attachment=5616:attachment]

When Luna-9 was built by NPO Lavochkin, they used the basic plan of the Luna-5 to 8, but with a couple minor changes. The airbag was inflated later, after the radar and other instruments were jetisoned. Here is a picture of the pre-Luna-9 craft, identifiable because the gas bottle is on the right-side modules, which is ejected a while before landing, to save weight. Most of what you're see when you look at Luna-9 is the engine and its fuel tanks, with some equipment attached to the outside. The oxydizer tank is spherical, and the fuel tank below it is toroidal, typical Russian design esthetics.

[attachment=5617:attachment]

The cone-shaped protrusion on the front of the airbag is also indicitive of Luna-8, some funky extending device on the lander that was absent from Luna-9.

Another difference is that the lander was pressurized in the earlier versions. The cycloramic camera looked out through a periscope inside a cylindrical glass window, somewhat like the Venera-9 camera. On Luna-9, the lander was open to vacuum, and a new higher-resolution camera was designed to operate in a vacuum. In fact, lots of pictures of "Luna-9" are actually pictures of the earlier vehicle. For example, the lander on display at the Engeriya Museum is Luna-8, naturally because they built those. At the Lavochkin Museum you will find the honest-to-god Luna-9. Here is a set of photos of Luna-8 (top row) versus Luna-9 (bottom row):

[attachment=5618:attachment]

The Mars-3 lander was somewhat different. They used a parachute and retro rocket, and the lander was encased in a foam shock absorber that was blasted off after it landed:

[attachment=5620:attachment]
Go to the top of the page
 
+Quote Post
Guest_BruceMoomaw_*
post May 16 2006, 01:23 AM
Post #44





Guests






Yeah, we discussed a lot of this over at (of all places) the "I'm back from the Europa Focus Group meeting" slot. Luna 8's airbags were inflated just before the retrorocket started -- but one of them was punctured by a faultily installed bracket, and the resultant gas jet threw the craft into a tumble which its attitude-control jets were unable to overcome. So, as one of the Luna 9 changes, they arranged for its airbags to inflate after the retrorocket had started, on the grounds that its pointable nozzles could emit enough thrust to overcome any attitude disturbances caused by small leaks in the airbags.

The very detailed report on the 1963-68 Soviet lunar missions in the Sept. 2000 JBIS reveals that 1965 marked a "stairstep" progress by the Soviets toward a successful landing -- starting with Luna 5, every mission got a little farther than the last one, only to be stopped by a new malfunction whose existence had been concealed by the earlier occurrence of the previous one.
Go to the top of the page
 
+Quote Post
edstrick
post May 16 2006, 09:49 AM
Post #45


Senior Member
****

Group: Members
Posts: 1869
Joined: 20-February 05
Member No.: 174



I suspect that for the Luna-3 data, fourier or wavelet (I've never played with those) processing to remove the fine diagonal noise pattern will probably work better than Don Mitchell's descreening, as it's a periodic ripple pattern, may be multi-spatial-frequency, and there may be larger, lower spatial frequencies in the noise.
Sometimes you have to peel layers of noise from an image like layers of an onion, as one noise removal or reduction may interfere with another. I'd remove the fine periodic noise first, then de-spike the data judiciously, then apply a special single-line filter to each original line of data, measuring it's local standard deviation (say along 1/20'th line) and not smoothing the low noise lines, while progressively median-filtering (tends to preserve edges between different uniform areas) noisier lines more and more as the noise level gets worse. Then you could tackle horozontal and vertical brightness striping.
Go to the top of the page
 
+Quote Post

11 Pages V  < 1 2 3 4 5 > » 
Reply to this topicStart new topic

 



RSS Lo-Fi Version Time is now: 17th November 2019 - 05:55 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.