Voyager Questions

[Astrosag]

Hi all, I had a few specific questions regarding the Voyager missions particularly dealing with its Data Storage and Transmission capabilities. <br /><br />The questions stem from an inquiry into limitations that the Voyagers may have had with storing data and transmitting it and how this affected nominal operations (i.e: installment of special maneuvers or something less severe).<br /><br />The only statistic I've come across as far as data storage is concerned is the following fact:<br /><br />" [The DTR is] capable of storing up to 500 million bits when no Earth station is available for real-time data transmission."<br /><br />Other info I've come across is that the Voyagers are real-time data acquisition and return missions meaing that the operating instruments are continuously collecting data and transferring it to the FDS for immediate transmission to the Earth. Everything but plasma wave data seemed to be transmitted directly w/o being stored.<br /><br />In my head, this pops a few questions as well a bit of contradiction. Are the Voyager's continuously sending data to the Earth and does NASA (today) simply tap into this stream of data when DSN time is available for the project? If so, what data is actually being stored (or was stored during the flybys) in the DTR - I'm assuming the DTR's main purpose was to store data during occultation periods when the ground stations weren't "avialable"?<br /><br />As far as ground station limitations are concerned, there doesn't seem to be any. During the flybys, the Voyagers had continuous ground support. Is there anything I may be overlooking here?<br /><br />I came to space.com b/c 1. my questions were always answered thoroughly in the past and 2. Voyager info is harder to get than I had thought. I appreciate any help, thanks!<br /><br /><br />"

 

[MeteorWayne]

Here's a link to the NASA Voyager page, I haven't had a chance to look through yet.... <br /><br />A lot of it is pretty old, but if you flop around tidbits like this (from 2003) are there.<br /><br />"Science data are returned to earth in real time at 160 bps. Real time data capture uses 34 meter Deep Space Network (DSN) resources with the project goal to acquire at least 16 hours per day of real time data per spacecraft. This goal is not always achieved due to the competition for DSN resources with prime mission projects and other extended mission projects. <br /><br />Once a week per spacecraft, 48 seconds of high rate (115.2 kbps) PWS data are recorded onto the Digital Tape Recorder (DTR) for later playback. These data are played back to Earth once every 6 months per spacecraft and require 70 meter DSN support for data capture. After transmission of the data (either real time or recorded) to JPL, it is processed and made available in electronic files to the science teams located around the country for their processing and analysis. "<br /><br /> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[Astrosag]

Yeah my group and I took a look at that which did give some good insight. However, we're looking for info regarding (or during) its primary mission. <br /><br />What I'm thinking or assuming is that the DTR was used because the rate of data acquisition was considerably higher than the spacecraft's data transmission rates (which we have)- since we don't have any info on how fast it acquired data (quatitatively), its hard to run with the idea. I believe that all 11 of the Voyagers' instruments were capable of acquiring data simultatneously (worked in parallel).

 

[vogon13]

IIRC, some of the instruments themselves have internal storage capability.<br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[MeteorWayne]

That's the only source I have handy unfortunately.<br /><br />That's something for the history books. Tried any library searches? <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[kurtwagner]

Here are some citations that may prove useful. I got these from Academic Search Premier and Science Direct. Your local college or university library should be able to obtain full text of these articles. - Kurt (Systems Librarian, William Paterson University of NJ)<br /><br />Communicating across the solar system<br />Acta Astronautica, Volume 12, Issue 9, September 1985, Pages 683-691<br />Macgregor S. Reid, Peter T. Lyman and Charles T. Force<br /><br />Now Voyager. By: Camhi, Elaine. Aerospace America, May2005, Vol. 43 Issue 5, p3-3, 2/3p;<br /><br />Remote sensing of the heliospheric boundary. By: Czechowski, A.. Advances in Space Research, Jul2004, Vol. 34 Issue 1, p79-87, 9p; DOI: 10.1016/j.asr.2003.05.046;<br /><br />The voyager interstellar mission<br />Acta Astronautica, Volume 40, Issues 2-8, January-April 1997, Pages 383-396<br />R. P. Rudd, J. C. Hall and G. L. Spradlin<br /><br />Titan's surface and rotation: new results from Voyager 1<br />Icarus, Volume 170, Issue 1, July 2004, Pages 113-124<br />James Richardson, Ralph D. Lorenz and Alfred McEwen<br /><br />Particles and fields measurements at Neptune with Voyager 2<br />Advances in Space Research, Volume 12, Issue 11, November 1992, Pages 55-70<br />S. M. Krimigis<br /><br />Engineering the voyager uranus mission <br />Acta Astronautica, Volume 16, 1987, Pages 75-82<br />Richard P. Laeser<br />