Here is a really nice New York Times story about NASA efforts to keep the Voyager spacecraft alive. They are approaching 50 years old. They are very far away. They are running low on the plutonium that keeps them warm and powered. The fuel for the thrusters is starting to clog the pipes. But NASA recently carried out a "Big Bang" effort to extend the life of these two spaccraft.
One of the 25 year-old engineers admitted that he treats the Voyagers like he treats his aging parents -- problems do crop up. But then he was reminded that his parents had been born AFTER the launch of the Voyagers.
The animation above shows where the two spacecraft are, and where they have been.
I worked on the build of the transmitter for Canberra, Australia. I built a portion of the user interface and control system for it. Got to watch the hardware go up at the factory In Dallas, Texas. It has an S-Band (2 GHz) to talk to Voyagers, and X-Band (8 GHz) for the more modern Deep Space Network.
ReplyDeleteFor GHz high power, we use 2 large Klystron tubes, a larger relative of your microwave oven’s magnetron. Power supply is a 2-car garage sized power supply for 38,000 Volts. Klystrons have to be heated to a suitable temperature to even turn them on. And of course, they need constant cooling, while sending 2 GHz or 8 GHz,, so there is a water tank, and a pump and piping system to each transmitter. The control console (I worked on it!) is a Linux system, with a custom graphical display to manage the entire system.
Then, of course, it had to be taken down, shipped to Canberra, and installed in the 70-meter dish - transmitters in the feed horn, water system and power supply in the base. Didn’t get to go there, but we had other projects to work on.
Project of a lifetime and wish I could’ve worked there longer, but I had to leave for some health issues.
Klystrons are very interesting. They rely on a resonant cavity to amplify their input. Very expensive. JPL keeps several sizes and frequencies in storage so they don’t have to use precious taxpayer budget to get one built.
Very cool. Thanks Mike!
DeleteExcellent NYT Article, Bill!
ReplyDeleteSome years ago, I met with a scientist at NASA, who was a wealth of knowledge in space communications- Dr. Bart Batson. We talked about the Voyager modulation format and I was amazed at how incredibly well designed Voyager was.This was 1992-ish.
We still have the Brain Trust of NASA. This country cannot afford to lose or even "De-Fund" NASA, as we have lost other institutions that provided basic science and advanced engineering, without which our country slips into a technology backwater.--73!
I'm afraid we have already slipped quite a bit.
DeleteIf you need plutonium It pays not to get it from the Libyans. Doc Emmett Brown learned that lesson the hard way.....
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