Would we have got to the moon with no semiconductors?
 

I was thinking this having a shower this morning, would we have got to the moon only using valves (or tubes considering it was an American project)?

Re: Would we have got to the moon with no semiconductors?
 

IMHO, yes we could have reached the moon without semiconductors, but it would have been harder.
I doubt that any significant computing power could have been carried onboard the space craft, but radio communication with valves, and a large ground based thermionic valve computer would have been possible.

A physically larger ship, at even greater cost would have been required, to carry more fuel in case the manually steered course was non optimum, and therefore used more fuel.
Valve based communication equipment though entirely possible would have added to the cost and weight penalty.

Re: Would we have got to the moon with no semiconductors?
 

It might have been possible, but there would be an increase in cost for the larger craft and its fuel, ground manpower etc. Who knows where the budgetary tipping point was between go and cancellation?

It is probably much more knife-egdey than we know.

David

Re: Would we have got to the moon with no semiconductors?
 

Certainly not impossible. The solid state technology used on the Apollo missions was quite primitive. The Apollo astronauts were basically jet test pilots chosen for their hands-on flying ability.

Didn't Apollo 11 land manually, without computer assistance in the final procedures?

Re: Would we have got to the moon with no semiconductors?
 

I suppose a lot of the digital stuff could have been done with cold cathode tubes no heater power and low current and not actually much bigger than similar transistor circuitry.

I guess we will never really know but its interesting to speculate.

Cheers

Mike T

Re: Would we have got to the moon with no semiconductors?
 

But using a lot bigger batteries as CC tubes struck at 70 volt. One of my projects as a TO on transmission duties was to design a time delay stepper to replace the clock pulses from the Auto exchange . Result, a TC strike voltage that used a RC network to time control the strike grid volts through a relay.

Re: Would we have got to the moon with no semiconductors?
 

As I understand it, the Russians perfected miniaturized Valves during the Cold War.

Their philosophy apparently was that Valves were more resilient to EMP.

The West had to shield their Semiconductors with heavy Lead shielding.

So I guess, the answer has to be yes.

Just might have taken a few years longer to achieve




Ian

Re: Would we have got to the moon with no semiconductors?
 

Higher voltage yes but not necessarily more power and don't forget one CCT tube can be a flip-flop that usually takes two transistors.

The battery size is determined by power as much as voltage.

Cheers

Mike T

Re: Would we have got to the moon with no semiconductors?
 

The story about the USSR sticking with valve technology because it was resistant to EMP is highly dubious. They had a lot of problems sorting out silicon planar technology, and only started producing cheap silicon transistors in the early 70s, a decade after the Europeans and even longer after the Americans.

See https://en.wikipedia.org/wiki/KT315

Special purpose valve technology was competitive with solid state in the analogue era, but was hopeless for digital. Imagine designing a (civilian) compact disc player without any transistors.

Re: Would we have got to the moon with no semiconductors?
 

Yes the CD player relies on semiconductor technology but not really discrete transistors.

The early ones were complex enough using IC's

You couldn't sensibly build a CD player just using BC107's

Be interesting to see it done though. :thumbsup:

Cheers

Mike T

Re: Would we have got to the moon with no semiconductors?
 

RE#9- I remember seeing a document in the late 60's where a Russian plane was forced down and on investigation it was discovered that the electronics were valve based. Till thy factored in EMP, and there's a lot of talk about EMP problems being dubious. But look at the input circuits of the receiver on a RT353 and there's circuitry to prevent the receiver etc failing from a 50W input to the aerial. The standard test was to stuff 50 W RF into the input for 30 secs. After that time the receiver should recover and function to spec. MOD excuse was two tank aerials coming into contact. I beg to differ.

Re: Would we have got to the moon with no semiconductors?
 

The Russian KURS space navigation system continued to use valves in Soyuz/Progress space vehicles until at least 2016, so yes, one could have made it to the moon using only valve technology.

There is reference to the above here http://digitalcommons.usu.edu/cgi/vi...11&context=etd on page 79 (there are plenty of other references on the net).

Re: Would we have got to the moon with no semiconductors?
 

I remember it was mentioned when I was on a guided tour of the Air & Space Museum in Washington, the computer on board the lunar module failed & the astronauts had to manually operate the rockets to bring it down.

Re: Would we have got to the moon with no semiconductors?
 

That's an interesting question, valves in space.

I'm not a valvey person, but I know the general method of how a simple valve works, and I know that most of the mass of a valve is in the glass, base, and pins.

In the vacuum of space, could the glass be omitted ?. Could a complete circuit be built as a PCB with naked valve elements sticking up from it ?.

Just a wild idea, but it would look really cool !.

Cheers,

Buzby

Re: Would we have got to the moon with no semiconductors?
 

I used to work with very, very large lasers driven by pulsed megavolt electron beams. The electrons had to be accelerated in vacuum, but the fast electrical drive circuitry was commonly insulated with oil and housed in big rectangular tanks. The oil-to-vacuum interface was a tricky part of the design (it had to be extremely low inductance and not prone to tracking along the insulator surface), but it could be done.

Then a Russian presenter at a conference showed a grainy black-and-white picture of a similar machine they'd actually built. Except that now the whole thing was vacuum-insulated and cylindrical in shape. He explained that the vacuum solved the interface problem. He didn't explain how they justified the huge cost and complexity of the pumping system.

Checking the numbers afterwards it became clear that the cylinder would be a conveniently snug fit into the payload bay of their Proton heavy launch system ...

Cheers,

GJ

Re: Would we have got to the moon with no semiconductors?
 

I remember a 1950's (possibly written in an earlier decade) SFstory where the valves in a space ship got damaged and the crew continued by putting on their space suits and opening the ship's interior to the vacuum of space.

Re: Would we have got to the moon with no semiconductors?
 

Yes, in the vaccuum of space, but not in a spacecraft that contains air.
Also, exposed valves without a glass envelope would I suspect interfere with each other. How do you stop electrons emmited from the heater of one valve from landing on the anode of a different valve, or indeed on any other exposed conductive part that is positive with respect to the valve heater.
A trace of say mercury vapour at minute pressure would short circuit things, even over considerable distances. 8 foot fluorescent lamps work fine with less than 200 volts driving a good fraction of an amp though 8 feet of near vaccuum.

Re: Would we have got to the moon with no semiconductors?
 

If you look into the details of the computers required to calculate take off windows & trajectories necessary to be able to reach a moon that orbits the earth, which itself both rotates and orbits the sun, the maths soon adds up, escecially as the sums needed updating on every launch hold or cancellation. That's before you take into account the IBM guidance computers installed in the Saturn rocket to stop it flying sideways or somersault top over bottom (as seen in those german V2 test films) and the two apollo guidance computers in the spacecraft themselves.
All the electronic minutiae of the moon landings is available on the NASA website, it's still pretty impressive how it was done and I dont understand much of it anyway! Without transistors and IC's aplenty, I doubt the rocket would've made it off the ground.

Re: Would we have got to the moon with no semiconductors?
 

'Would we have got there' is a fascinating question.

If 'we' is the human race, almost certainly yes in my opinion. The soviets would likely have managed it, in the usual hazardous, cramped and robust style which was their MO at the time. I don't think processing power is a major issue, although weight and therefore expense would have altered the project in ways we can't realistically calculate.

It could even have ended the cold war early..an international effort perhaps.

Dave

Re: Would we have got to the moon with no semiconductors?
 

Do a search for Rope Memory. That was program ROM, and was hardwired by lacing magnetic cores into a rope to represent a set of instructions

https://www.youtube.com/watch?reload=9&v=-BlivdwXRZU