23rd Nov 2020, 4:11 am | #21 |
Nonode
Join Date: May 2016
Location: Cornwall, UK.
Posts: 2,336
|
Re: Would we have got to the moon with no semiconductors?
BBC World Service produced the fabulous '13 Minutes To The Moon' series about Apollo 11, including an episode on the rope memory and the computer system. Now there's a second series on Apollo 13, as the first was so well received. I was delighted to find there's a lot of detail and extra interviews. The conceit being that they drip-feed the listener enough information throughout the series so that in the final episode the titular '13 minutes' of radio traffic from descent to landing are played without commentary because one can by then follow the conversation in real time.
|
23rd Nov 2020, 9:02 am | #22 | ||
Nonode
Join Date: Jun 2016
Location: Bognor Regis, West Sussex, UK.
Posts: 2,300
|
Re: Would we have got to the moon with no semiconductors?
Quote:
The docking process needed to redock the moon lander crew capsule with the command module was switched on in error. Ground control decided it was safe to ignore the error and continue the landing. Neil Armstrong did overide the landing computer because the programmed landing site was boulder strewn, he took over and guided the lander to a clear area, nearly running of fuel in the process. Peter |
||
23rd Nov 2020, 10:07 am | #23 |
Dekatron
Join Date: Apr 2009
Location: Oxfordshire, UK.
Posts: 4,935
|
Re: Would we have got to the moon with no semiconductors?
Peter is correct and the question of the computer "failing" on Apollo11 is potentially a very misleading one. Let's start by saying that on the next flight, and all the subsequent ones, it did just what they intended it to do.
Investigation of what went wrong with the computer during Apollo 11 revealed a number of problems, mainly about how three different radar systems where configured, all interacting with the computer at the same time and so over-loaded it. The problem was sorted out before the next mission flew just a few months later, Apollo 12 making a pinpoint landing very close to an old 'Surveyor' spacecraft which landed some years earlier. They were able to walk over to it and cut bits off which were brought back for analysis. I don't believe the flights would have possible with valve equipment. B
__________________
Saturn V had 6 million pounds of fuel. It would take thirty thousand strong men to lift it an inch. Last edited by Bazz4CQJ; 23rd Nov 2020 at 10:14 am. |
23rd Nov 2020, 10:48 am | #24 |
Nonode
Join Date: May 2007
Location: Preston, Lancashire, UK.
Posts: 2,511
|
Re: Would we have got to the moon with no semiconductors?
Surely a more relevant and fundamental question is "If solid-state technology hadn't been invented/developed at the time it was, how would valve technology have developed during the fifties and sixties and subsequently?"
Andy |
23rd Nov 2020, 11:14 am | #25 |
Dekatron
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
|
Re: Would we have got to the moon with no semiconductors?
No problem getting to the moon without semiconductors....just point, shoot and steer.....DOA.
Lawrence. |
23rd Nov 2020, 11:27 am | #26 |
Moderator
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 22,896
|
Re: Would we have got to the moon with no semiconductors?
Yes, getting back is the defining achievement.
There's an old saying, "A good landing is any one you can walk away from. A very good landing is one where you can use the aircraft again" We'd have to modify that to swim for the Apollo missions. There have actually been volunteers for a one-way mission to Mars. I assume they would want to land softly and to be able to look at a few rocks. In the popular press, mass has to be expressed in London buses, volume in Olympic swimming pools. Maybe computing power ought to be expressed in Lunar Landers? David
__________________
Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done |
23rd Nov 2020, 11:36 am | #27 |
Nonode
Join Date: Sep 2017
Location: Stockport, Cheshire, UK.
Posts: 2,004
|
Re: Would we have got to the moon with no semiconductors?
Large areas seem to be measured in the size of Wales for some reason, as a few stand up comedians have pointed out.
Large explosions & acts of nature seem to be in atomic bombs, usually the Hiroshima one.
__________________
Hello IT: Have you Tried Turning It Off & On Again? |
23rd Nov 2020, 12:00 pm | #28 |
Moderator
Join Date: Jun 2003
Location: Oxford, UK
Posts: 27,960
|
Re: Would we have got to the moon with no semiconductors?
Back on topic please.
|
23rd Nov 2020, 12:52 pm | #29 | |
Heptode
Join Date: Jun 2017
Location: Southport, Merseyside, UK.
Posts: 646
|
Re: Would we have got to the moon with no semiconductors?
Quote:
A lot of heater current needed too I imagine.
__________________
Time flies like an arrow, fruit flies like a banana |
|
23rd Nov 2020, 2:05 pm | #30 | |
Heptode
Join Date: Oct 2011
Location: Culcheth, Cheshire, UK.
Posts: 654
|
Re: Would we have got to the moon with no semiconductors?
Quote:
The emitting surface used what would now be called nano-technology, and consisted of millions of tiny spikes. I'd be pleased if anyone can confirm I'm not imagining this. Cheers, Buzby |
|
23rd Nov 2020, 2:48 pm | #31 |
Moderator
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 22,896
|
Re: Would we have got to the moon with no semiconductors?
Confirmed!
Never came to anything, though... at least nothing I heard of. David
__________________
Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done |
23rd Nov 2020, 2:59 pm | #32 | |
Dekatron
Join Date: Nov 2006
Location: London, UK.
Posts: 3,496
|
Re: Would we have got to the moon with no semiconductors?
Quote:
This is an MOD issue VHF/UHF amplifier. It looks 80's to me. It contains at least one nuvistor, several transistors and a valve that I can't identity without taking the unit apart. It is hugely ruggedised and I wouldn't be surprised if it was for use in fighter planes. As far as the original question, it's an interesting one. The will to do it, within the context of the Soviet/US competition for supremacy and the reasons why that was so pronounced - well, that wouldn't have gone away if semiconductors weren't on the scene. I have often wondered how systems that simply couldn't be allowed to fail (e.g, mechanical switches for various commands) were made fail-proof, even if it was by replication.
__________________
Al Last edited by Al (astral highway); 23rd Nov 2020 at 3:09 pm. |
|
23rd Nov 2020, 3:01 pm | #33 | |
Dekatron
Join Date: Apr 2009
Location: Oxfordshire, UK.
Posts: 4,935
|
Re: Would we have got to the moon with no semiconductors?
Quote:
B
__________________
Saturn V had 6 million pounds of fuel. It would take thirty thousand strong men to lift it an inch. |
|
23rd Nov 2020, 3:59 pm | #34 |
Heptode
Join Date: Oct 2011
Location: Culcheth, Cheshire, UK.
Posts: 654
|
Re: Would we have got to the moon with no semiconductors?
It probably wasn't developed because valve stuff was long out of fashion by then.
But if there was no alternative, it could have been a solution to the heat problem. So by now we would have low power, high speed, minature valve-based circuits, built using layer technology, a bit like ICs. I don't know how small a 'thermionic' gate can be built, I don't know the maths, but I'm sure if it was the only option it would have been done. Cheers, Buzby |
23rd Nov 2020, 5:33 pm | #35 |
Nonode
Join Date: Jan 2010
Location: North Somerset, UK.
Posts: 2,130
|
Re: Would we have got to the moon with no semiconductors?
It seems reasonable to suppose that without semiconductors, that valve technology would have improved.
I suspect that such improvements would have relatively minor however. By the 1950s valves were a mature technology with only limited opportunities for improvements. Cheaper ? almost certainly due to semi automated mass production. More reliable ? almost certainly due to better quality control. Smaller, yes but only up to a point due to electrode spacing and heat dissipation requirements. Lower power consumption, probably, though the later battery valve receivers were already very good in this respect. Some TV valves were already as small as was sensible, and some types arguably TOO small and prone to a short life. As has already been said, the Russian military used sub miniature wire ended valves. Without semiconductors, this sort of valve would probably have been widely used in consumer electronics. If sufficiently long lasting and reliable they could be soldered into place, thereby avoiding the cost/space/weight penalty of valve holders, and eliminating one cause of faults. I recall a late relative who used a very compact valve hearing aid, HT was 22.5 volts and LT 1.5 volts from a single C cell. I think that it used wire ended valves. Shirt pocket sized. |
23rd Nov 2020, 5:46 pm | #36 |
Guest
Posts: n/a
|
Re: Would we have got to the moon with no semiconductors?
Another snag is you only get NPN valves.
|
23rd Nov 2020, 5:47 pm | #37 |
Dekatron
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
|
Re: Would we have got to the moon with no semiconductors?
If they had carried on the development, the valve technology would have hit the buffers, just like propeller, internal combustion engine, jet engine and steam piston power technologies would have done/will do, it's not rocket science (scooze pun)
Lawrence. |
23rd Nov 2020, 5:53 pm | #38 |
Dekatron
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 14,005
|
Re: Would we have got to the moon with no semiconductors?
For space applications, cooling is a big problem; in zero gravity there are no convection-currents, so everything that generates much heat has to be cooled by radiation or conduction (or fans).
Semiconductors - lacking heaters - obviously have an advantage here for space applications; likewise the 'power budget' of spacecraft is often rather tight so not-needing-heaters is a big benefit. Remember though that the first Russian Sputnik beacon transmitter was valve-based, and ran on batteries. The US's catch-up satellite launched a few months later used transistors.... Semiconductors-in-space used to have one significant issue - particularly with memory-devices there was an issue with high-energy subatomic-particles which - if they passed through a semiconductor memory-cell - could release enough electrons to 'flip' the cell's state! There could be advantages to using old-style ferrite core-memory. |
23rd Nov 2020, 5:58 pm | #39 |
Heptode
Join Date: Jan 2003
Location: Tewkesbury, Gloucestershire, UK.
Posts: 693
|
Re: Would we have got to the moon with no semiconductors?
Couldn't orbital calculations have been done using valve analogue computers?
__________________
Keith Yates - G3XGW VMARS & BVWS member http://www.tibblestone.com/oldradios/Old_Radios.htm |
23rd Nov 2020, 6:10 pm | #40 | |
Heptode
Join Date: Oct 2011
Location: Culcheth, Cheshire, UK.
Posts: 654
|
Re: Would we have got to the moon with no semiconductors?
Quote:
Just look at what an LED could do in 1975, glow a dim red !. Now they can illuminate football pitches, replace lasers and CRTs, and cost next to nothing. Thinking that valve progress would be limited doesn't take into account new manufacturing and material technologies. Look at circuit manufacture. From tag-strips to single-sided SRBP took 100 years. From there to 64-layer boards took 50 years. If valve tech was re-engineered to be PCB based, you could imagine a PCB-like structure, with multi-layers of 'valve' elements, using cold-emitters, and printed interconnects. In fact, in a world devoid of semiconductors, I can't even imagine what technology would take its place, but I know something would. Cheers, Buzby |
|