Voyager 1 and 2 Approaching Interstellar Space

[W1RKW]

I've been following Voyager 1 and 2 for a number of years and it always fascinates me that these 2 spacecraft are still alive and well and able to communicate over such a vast distance.  All indications from NASA/JPL suggest that both are poised to cross into interstellar space.  It would be interesting to know what will happen to comms once this crossover occurs. 

http://www.thebunsenburner.com/news/voyager-to-bid-farewell-to-solar-system/

[Bill, KD0HG]

Yes, it is a fascinating story.

I am curious about some details of the radio communications used..Frequency bands, transmitter powers and antenna gains. Even the doppler shift. Solid state or vacuum tube transmitters?

I see the round trip radio time is now something like 33 hours. The speed of light is so terribly slow.

VGER

Bill

[W1RKW]

Bill, Here's an interesting read on the technical aspects of the Voyagers.

http://descanso.jpl.nasa.gov/DPSummary/Descanso4--Voyager_new.pdf

Note: I had trouble viewing this in my browser. You may have the same too. What I did  was save it directly to my harddrive and viewed it locally.

Quite an engineering feat given the time, if you ask me.

Paragraph 6.3.6 talks about future plans for the DSN.  Given this was written a long time ago, it is apparent that staying linked to these 2 spacecraft while they're still operating is important.

[kb3ouk]

Well, from reading that, they are using solid state and travelling wave tube amplifiers on S band, and a TWT amp on X band. the S band solid state amp put out 15 watts on high power, and the S band TWT puts out 19 watts on high power. The X band TWT puts out 18 watts on high power. the high gain antenna for S band has 36 dB gain, the X band antenna has 48 dB gain. The uplink to Voyager is a 20kw S band transmitter, but there must've been a planned 400kw transmitter for uplink that isn't used, because they mention it in that file.

[W3LSN]

I've always been fascinated by the earlier Pioneer 10/11 missions. In the case of Pioneer 10, it was launched in 1972 as a kind of warm-up act for the Voyager series. It was the first probe to visit Jupiter and pass thru the orbits of the outer planets. It was also the first that was deliberately if unavoidably intended to leave the solar system when its mission was completed.  Although Pioneer 10's mission was declared ended in 1997, Houston was still in contact with the spacecraft until fairly recently having received its last useful telemetry in April 2002.  The signal was incredibly weak at that point, and the last confirmed telemetry signal was heard in January 2003.  After that, Pioneer 10 did not responded to commands, and so no further contact has been attempted. Pioneer 10 is now more than 105AU distant from our Sun, and headed in the general direction of the star Aldebaran at a velocity of over 12km/hr.  It may reach Aldebaran in about 2-million years.

Pioneer 10 and also Pioneer 11 were notable for the "interstellar greeting card" in the form of a gold-anodized aluminum plate.  The plate was design by Carl Sagan and pictured two naked humans as well as diagrams that would let any extraterrestrial beings determine Pioneer's point of origin. 

73, Jim
WA2AJM/3

[WA1GFZ]

Hey Mom look at this thing that fell into the back yard last night.