Tube electronics in space?

Artlav

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Were tube electronics used in space, or was the low weight of then-invented transistors a winning factor?

I just thought, that in the vacuum of space the tubes won't need their heavy glass, and so should be easier to make, and be quite lighter.
You could even make a kind of integrated circuits by putting valve parts and passive components as close as possible where on earth there would have been glass in the way.

So, does anybody know what used did the tubes seen in space, and were there ever naked ones?
 

Urwumpe

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I think the worse problem is the radiation in space for the tubes. While more resistant against EMP, they are pretty sensible to beta and proton radiation.
 

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I think so too. The tubes would act like a Geiger Counter would do if a particle strikes them. Also the tubes must be kept hot and running all the time, that should be pretty significant in the power budget.

That last point should also should be a problem for the internal temperature management. Wikipedia says that the electron emission at the cathode happens around 800°C, so the tube itself should be pretty hot. Also the High Voltage should be a problem, with corona discharges at low pressures and so on.

(Maybe also more susceptible to break during launch?)
 

Andy44

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Even without the glass they are still heavier and bulkier. Also they require higher voltages and power, which is right behind mass in spacecraft design considerations.

Have they ever been used? A quick google search doesn't find a definitive yes or no answer on whether Sputnik's transmitter used tubes or not.
 

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Just a thought, isn't the Ion thrust type engine basically a valve(UK equivalent) with bits chopped off?

N.
 

Andy44

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Yes, and microwave communications uses traveling wave tube amplifiers, which is a vacuum tube similar to the klystron in your microwave oven. I guess The Mighty Probe Luna 3 probably had television camera tubes in it. So I suppose for specialized applications tubes were, and still are, used in space vehicles. But wherever they can be replaced with lightweight, low-power transistors they will be.
 

Artlav

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Have they ever been used? A quick google search doesn't find a definitive yes or no answer on whether Sputnik's transmitter used tubes or not.
Similar over russian sources - it would appear that the transmitter was made on 1П24Б tubes ( http://istok2.com/data/166 ), but i can't find any solid/official mentions, only occasional guesswork.
51kg of silver–zinc batteries were used to power it for two weeks, but that does not tell anything specific.

The "Radio" magazine from 1957 just wax about the importance of the event and provides basic description of the equipment, without mentioning the details.
However, in some pictures of the electronics from Sputniks 1 and 2 there are some shapes that look like tubes.

Yes, for imaging for example (like Voyager's), or as other detectors. :p
I guess that does not count.
Mostly, i'm interested if the vacuum of space is actually usable as an environment for the naked valves.
Radiation can be solved by regular shielding, but heating can be a problem, i guess.
 

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What about the final power Amp stage of the RF tx'ers. Did they have big enough transistors in the early days?
 

Urwumpe

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Explorer 1 had transistor electronics at least. Syncom 2 as well - it only had 2 Watt of transmitter power. Apollo used 20 Watt.

The S-band power amplifier on Apollo had been a TWT, a TWT had also been used in the Space Shuttle. Not sure if a TWT counts as typical electronics tube, it is similar.
 
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Quick_Nick

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I don't know if this is what you're looking for; just a simple Google search.
http://www.ncbi.nlm.nih.gov/pubmed/18699417 (1979)
Based on the successful operation of the electron gun on ISEE 1 the safe operation in space of an open vacuum tube has been established.
And may actually perform better above 1000km than a "vacuum" tube.
 
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paddy2

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2 Watts .. not the 30kw HF Tx'ers I worked on then.

As an aside, surely the heat from the cathode could keep the capsule warm, its cold in space you know!
 

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Tubes were superior to solid state devices for high frequency applications well into the 1960s in the US and probably longer in the USSR. Plus you could run higher currents through them and prevent the need for further amplification. But the waste heat and power inefficiencies make for an interesting trade off.

It would be really interesting to see more schematics from early spacecraft of you've got em.
 
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