IPB

Welcome Guest ( Log In | Register )

2 Pages V  < 1 2  
Reply to this topicStart new topic
Voyager Spacecraft Hardware
Liss
post Oct 26 2007, 08:50 AM
Post #16


Junior Member
**

Group: Members
Posts: 39
Joined: 18-July 05
Member No.: 439



Oh well... May I ask more questions?

1. The 16 hydrazine engines of Voyager -- were these all of the 0.2 lbf MR-103H type or the four TCM engines were of a larger thrust?
2. What was the initial velocity of V2 and V1 after separation with the Star 37E kick-up motor?
Go to the top of the page
 
+Quote Post
rlorenz
post Nov 3 2007, 01:27 PM
Post #17


Member
***

Group: Members
Posts: 417
Joined: 23-February 07
From: Occasionally in Columbia, MD
Member No.: 1764



QUOTE (Paolo @ Feb 4 2007, 05:29 AM) *
JPL started using black thermal blankets on Mariner 4. They had had many issues with thermal control on Mariner 2.
From the paper "Mechanical evolution of the Mariner spacecraft" by J.N. Wilson (1966)
"Although the black shields absorbed more solar energy than did the Mariner II white shields, the uncertainty in the amount of energy absorbed was less. Increased layers of insulation allowed the total heat transmitted through the shield to be reduced to a minimum"


Interesting - I guess the gold-foil stuff (and the aluminized mylar) have advantages more for
reproducibilty/relibaility than performance/cost specifically - paint is notoriously hard to get right (qv
the overheating problems with Genesis - see Space Systems Failures by Harland and myself)

There is of course the old joke

"Why does JPL make all its spacecraft gold-plated ?"
Because pure gold is too heavy....
Go to the top of the page
 
+Quote Post
Guest_PhilCo126_*
post Nov 12 2007, 07:41 PM
Post #18





Guests






Noticed Part II is on the Voyager computers, so it belongs in this Voyager hardware topic wink.gif
http://history.nasa.gov/computers/contents.html
Go to the top of the page
 
+Quote Post
sci44
post Nov 20 2008, 08:51 PM
Post #19


Junior Member
**

Group: Members
Posts: 63
Joined: 18-November 08
Member No.: 4490



I was wondering if anyone knew the memory capacity & specs of the Digital tape recorder (DTR) onboard Voyager? I can't find it on the usual NASA sites. I know that they uploaded new image compression software on one of the "spare" 1802 processors for the Uranus/Neptune flyby to increase the number of images captured and save DSN time. Are there JPG type artifacts on those images, or was it just lossless RLE/Huffman type encoding?
Go to the top of the page
 
+Quote Post
climber
post Nov 20 2008, 09:35 PM
Post #20


Senior Member
****

Group: Members
Posts: 2625
Joined: 14-February 06
From: Very close to the Pyrénées Mountains (France)
Member No.: 682



QUOTE (sci44 @ Nov 20 2008, 09:51 PM) *
I was wondering if anyone knew the memory capacity & specs of the Digital tape recorder (DTR) onboard Voyager? I can't find it on the usual NASA sites. I know that they uploaded new image compression software on one of the "spare" 1802 processors for the Uranus/Neptune flyby to increase the number of images captured and save DSN time. Are there JPG type artifacts on those images, or was it just lossless RLL/Hoffman type encoding?

I've got some infos 'sci44'. There are from JPL Publication 89-24, june 1,1989 "The Voyager Neptune Travel Guide".
"The DTR has three speeds in use at Neptune encounter (...) 115.2 Kbps (record only), 21.6 Kbps (playback only) and 7.2 Kbps (both record and playback). There are 8 tracks on the DPR. Each of these can hold 12 images if only images are recorded" (...) "It's important to play back quickly so that the tape recorder can be filled again. But, playbacks interfere with science gathering and require certain DSN configurations that are not always available".
I hope it helps.


--------------------
Go to the top of the page
 
+Quote Post
sci44
post Dec 1 2008, 10:56 PM
Post #21


Junior Member
**

Group: Members
Posts: 63
Joined: 18-November 08
Member No.: 4490



Thanks for that - so the DTR can hold 8 tracks, 12 images per track. I wonder if thats with compression, or uncompressed? If uncompressed, well each image is 256 x 256 x 8 bits (256 grey scale) = 64K. 8 x 12 x 64 = 6144k, or 6 megabytes at a guess. That means next time you go out and take a picture with your new camera, just 1 picture at a high resolution is equal to all the data storage Voyager 2 had available during its Jupiter/Saturn/Uranus/Neptune flyby! Now as I said, they did implement better compression for the Uranus/Neptune flybys - I have to assume simple run-length compression for those old 1802's. If you look at the raw Cassini images, you will see a "comb" like effect - run length compression is applied to scan lines in pairs, but at the point where it fills up available space, the alternate vertical pixel is dropped. Is the same compression applied to Uranian/Neptunian images? Are there "Raw" images anywhere?
Go to the top of the page
 
+Quote Post
Guest_PhilCo126_*
post Dec 15 2008, 03:53 PM
Post #22





Guests






http://www.goldenrecord.org/
Go to the top of the page
 
+Quote Post
Jared Robertson
post Dec 26 2008, 01:59 AM
Post #23


Newbie
*

Group: Members
Posts: 2
Joined: 25-November 08
From: Bellingham, Washington
Member No.: 4495



That's an awesome site. I tried to find a copy of the CD-ROM, but was stymied, so this was a nice substitution treat. (I did manage to locate a copy of the hardback book.)

I did a little digging to find out why the record is plated with gold, but didn't find any definitive information. Is it just because gold is shiny and might attract the attention of anyone examining the spacecraft, saying, "Hey! We, the people who built this emissary, value the contents of this box! Pay close attention to (possibly worn) diagrams."

I've always thought of gold as being very soft, and therefor not exactly ideal material to withstand space travel and its variety of unmitigated rigors.


--------------------
The mediocrity of my thinking is concealed by the majesty of my language.
Go to the top of the page
 
+Quote Post
ugordan
post Dec 26 2008, 11:50 AM
Post #24


Senior Member
****

Group: Members
Posts: 3569
Joined: 1-October 05
From: Croatia
Member No.: 523



QUOTE (Jared Robertson @ Dec 26 2008, 02:59 AM) *
I've always thought of gold as being very soft, and therefor not exactly ideal material to withstand space travel and its variety of unmitigated rigors.

Whether the material is gold or titanium doesn't make much difference when you're traveling 17 kilometers per second and run into a dust particle!


--------------------
Go to the top of the page
 
+Quote Post
nprev
post Dec 26 2008, 05:33 PM
Post #25


Senior Member
****

Group: Moderator
Posts: 7087
Joined: 8-December 05
From: Los Angeles
Member No.: 602



Gold is very resistant to corrosion (like from atomic oxygen in LEO, or in this case prolonged passage though an interstellar gas cloud), and an excellent conductor of both heat & electricity (therefore resistant to spot-arcing or uneven thermal flex). It's a good material for this application.


--------------------
A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
Go to the top of the page
 
+Quote Post
Liss
post Jul 22 2009, 07:29 PM
Post #26


Junior Member
**

Group: Members
Posts: 39
Joined: 18-July 05
Member No.: 439



QUOTE (sci44 @ Nov 21 2008, 12:51 AM) *
I was wondering if anyone knew the memory capacity & specs of the Digital tape recorder (DTR) onboard Voyager?

Per Voyager Backgrounder ( NASA Release No. 80-160, http://ntrs.nasa.gov/archive/nasa/casi.ntr..._1981001583.pdf ), DTR is a 0.5 in by 328 meters 8-track magnetic tape recorder capable of storing 536 million bits. 96 images may be stored on it.
Go to the top of the page
 
+Quote Post
Liss
post Jul 22 2009, 07:36 PM
Post #27


Junior Member
**

Group: Members
Posts: 39
Joined: 18-July 05
Member No.: 439



QUOTE (Liss @ Oct 26 2007, 12:50 PM) *
The 16 hydrazine engines of Voyager -- were these all of the 0.2 lbf MR-103H type or the four TCM engines were of a larger thrust?


Well, replying to myself.
Per Voyager Backrounder, Voyager Mission Module has 16 x 0.2 lbf thrusters, four for trajectory corrections and 12 (in two redundant branches) for attitude control. I guess these are of MR-103 family; which version exactly?
Then, Voyager Propulsion Module has 4 larger thrusters for pitch and yaw control, these were 100 lbf items of MR-104 family -- which excactly? -- and 4 smaller ones for roll control with a thrust of 5 lbf. I couldn't find the designation for these.
Go to the top of the page
 
+Quote Post
Ian R
post Sep 30 2010, 03:37 PM
Post #28


Member
***

Group: Members
Posts: 553
Joined: 18-July 05
From: Plymouth, UK
Member No.: 437



This seems like an appropriate thread to post this in — here are several archive clips showing the Voyager spacecraft in various stages of construction:

http://www.footagevault.com/clip/FTV-0001398
http://www.footagevault.com/clip/FTV-0001399
http://www.footagevault.com/clip/FTV-0001400
http://www.footagevault.com/clip/FTV-0006097
http://www.footagevault.com/clip/FTV-0006099
http://www.footagevault.com/clip/FTV-0006205




--------------------
Go to the top of the page
 
+Quote Post
Ian R
post Sep 30 2010, 03:53 PM
Post #29


Member
***

Group: Members
Posts: 553
Joined: 18-July 05
From: Plymouth, UK
Member No.: 437



A NASA film called "Project Voyager" can also be found on the FootageVault website:

http://www.footagevault.com/clip/FTV-0006211
http://www.footagevault.com/clip/FTV-0006212
http://www.footagevault.com/clip/FTV-0006213
http://www.footagevault.com/clip/FTV-0006214
http://www.footagevault.com/clip/FTV-0006215

Of interest is the primitive animation of a "possible" encounter with Uranus, where the rings are noticeably absent, given that they had yet to be discovered at the time this documentary was produced!


--------------------
Go to the top of the page
 
+Quote Post
Liss
post Jul 9 2014, 09:11 AM
Post #30


Junior Member
**

Group: Members
Posts: 39
Joined: 18-July 05
Member No.: 439



QUOTE (Analyst @ Jan 13 2006, 11:23 AM) *
The authors are citing: NASA news releas No. 77-136 (Voyager Press Kit). Does anyone has a link?


Found it and just uploaded to the NSF forum: http://forum.nasaspaceflight.com/index.php...0;attach=591860
(6 Mbyte -- too large to upload here)
Go to the top of the page
 
+Quote Post

2 Pages V  < 1 2
Reply to this topicStart new topic

 



RSS Lo-Fi Version Time is now: 24th October 2014 - 12:44 PM
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.