[HN Gopher] Reverse-engineering the electronics in the Globus an...
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Reverse-engineering the electronics in the Globus analog
navigational computer
Author : rcarmo
Score : 141 points
Date : 2023-03-06 08:24 UTC (14 hours ago)
(HTM) web link (www.righto.com)
(TXT) w3m dump (www.righto.com)
| IYasha wrote:
| Ironically, this page is blocked in Russia...
| yurish wrote:
| It is not blocked for me. I am in Russia.
| psychphysic wrote:
| Does someone open access mirror? Blocked for me.
| antegamisou wrote:
| https://web.archive.org/web/20230306135640/http://www.righto...
| psychphysic wrote:
| Thank you!
| aivisol wrote:
| P217 germanium transistors - I remember them. They were a top at
| the P213-P217 range, normally you would be lucky to get hold of
| 213 or 214. Used them on the last stage of my first audio
| amplifier.
| kens wrote:
| An interesting thing about these transistors is they look like
| standard power transistors in a metal TO-3 package. However,
| the transistor itself is in a round metal package, and the
| metal flange is separate, and holds down the transistor. Soviet
| electronics is like an alternate universe where things are
| similar but also unexpectedly different. (Vintage IBM
| electronics has the same feel.)
| mothsonasloth wrote:
| Really cool, I have often wondered about the "maps" in the
| Russian helicopter cockpits.
|
| I think they also move depending on the heading and direction of
| the helicopter to show the relative position for navigation.
|
| Would be interesting to see how they worked.
|
| Pic of cockpit - https://www.alamy.com/dashboard-in-a-russian-
| soviet-helicopt...
| codemusings wrote:
| Ken Shirriff is just awesome. He regularly posts on Mastodon1
| about his reverse engineering endeavors of old x86 chips.
|
| [1] https://mastodon.social/@kenshirriff@oldbytes.space
| kens wrote:
| Thanks! I primarily post on Twitter as @kenshirriff but also
| post on Mastodon.
| NextHendrix wrote:
| I love seeing teardowns of old space tech. Having worked on
| safety critical projects I know that if something is proven and
| works it is generally not replaced unless something substantially
| better comes along, so I wonder if the soyuz still flies with
| these electromechanical wonders.
| kens wrote:
| I think the Soyuz-TMA spacecraft (2002) upgraded to the Neptun-
| ME system, which has digital displays rather than the Globus.
| Scubabear68 wrote:
| This thing is just amazingly cool and clever. I am curious if
| this was a critical piece of capsule instrumentation or more of
| an onboard backup? I have no idea how Russian space missions are
| run so it's not clear to me how much is done at their equivalent
| of ground control vs. what is done on board.
|
| In particular I am wondering about that landing mode.
| ezconnect wrote:
| It is custom made for each spacecraft, since it can only rotate
| on the planned flight path. I think it's a good guide for the
| astronaut where they are in the globe and the globe also have
| markers of communication tower they can contact.
| kens wrote:
| At least on the early Soviet space missions, the cosmonauts had
| almost no control by default and most of the control was by
| onboard sequencing. The controls were actually locked with a
| combination lock. The Globus was more of a backup. The landing
| mode feature wasn't added until 1967.
|
| Based on the book "Beyond" (Walker) about the early Soviet
| space program and Yuri Gagarin. A very interesting book and I
| recommend it.
| squarefoot wrote:
| What a beautiful device! If I had one I would struggle between
| wanting to preserve it untouched and repurposing it with
| mechanical and electronics implants as a display to see where a
| given space object is; imagine watching it track the ISS in real
| time. Preserving it would probably win, but now I'll hardly
| resist the temptation to buy the first globe I see at the next
| pawn shop...
| JKCalhoun wrote:
| In fact, try to find a second if you can, it will resolve your
| first dilemma (or it would for me, ha ha).
| DaiPlusPlus wrote:
| Everyone here watches Curious Marc on YouTube, right?
| st_goliath wrote:
| If not, here are part 1 and 2 of opening up and repairing the
| thing:
|
| - https://www.youtube.com/watch?v=dmHaCQ8Ul6E
|
| - https://www.youtube.com/watch?v=CP5dfjxdkQ4
|
| And a 47 second time-lapse video of the Globus doing 7 orbits:
|
| - https://www.youtube.com/watch?v=nDHtJy9cpC0
|
| (there is an earlier time lapse video as well, linked in the
| blog post)
| iamtedd wrote:
| And, of course, his and his friends' amazing Apollo Guidance
| Computer restoration series: https://www.youtube.com/playlist
| ?list=PL-_93BVApb59FWrLZfdli...
| jhallenworld wrote:
| If you follow the channel you know all about Master Ken.
| neilv wrote:
| I hope someone makes a replica, including the rolling physical
| globe (though maybe with an Arduino or RasPi in place of some of
| the clockwork).
|
| Or maybe it inspires other uses of a rolling physical globe. For
| example, a steampunk "global video meeting" device
| (Zoom/Jitsi/etc. client), including globe that animates to show
| participants. Vintage round B&W CRTs to display them, old-timey
| radio audio distortion, optional transatlantic accent filters,
| brass and gauges, etc. Maybe for a novelty in an office common
| area, kids' technology museum, or somewhere. If it was
| reproducible open source designs, the devices could talk to each
| other, such as between two museums, maybe to shake up the
| familiarity of modern video communications and remind what a
| wonder it is that we can interact around the world casually.
| kens wrote:
| The clever thing about the globe is that it doesn't do
| arbitrary rotations, so the mechanical connections are
| simplified. Instead, it has two degrees of freedom through two
| fixed, co-axial shafts.
|
| Specifically, the globe rotates at an angle of 51.8deg,
| corresponding to the launch angle of the spacecraft. Spinning
| the globe at this angle gives you the orbital track without any
| real computation. The other rotation is the Earth around its
| axis. The trick here is that the equator is a fixed frame,
| while the two hemispheres are rotated based on the input shaft.
| JKCalhoun wrote:
| To simplify it down to being 3D printed and driven/positioned
| by a computer should indeed be straightforward. It looks like a
| lot of the mechanical complexity is there for lack of a digital
| computer.
|
| A couple of servos, one to roll, one to pitch the ball and then
| a lot of quaternion math on the Pi should get you there.
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(page generated 2023-03-06 23:01 UTC)