Hello and welcome back.
If you follow the channel, you know that we recently opened a Soyuz Navigation Computer
better known as the Globus.
Inside, we found an amazing analog computer, powered by lots of gears and a very little
bit of electronics.
This oddly anachronistic, yet magnificent instrument, was used until 2002 in the Soyuz
T and Soyuz TM capsule.
Our unit, which we could tell from the markings was made for the Apollo-Soyuz mission, had
suffered a big fall that had dislodged the main shaft, and its internal wiring had all
been cut.
We repaired the mechanical damage in episode 1, and figured out the damaged wiring in episode
2.
So much so, that we could power it up again and fly orbits around its gorgeous globe,
as it was originally meant to.
But there is one more function that we have not yet revived, and it is an important one.
This function is the landing point prediction.
A feature so important, that the instrument was kept flying until 2002, as a backup to
the electronic systems.
If we can make this landing function work again, we will have completed the restoration
of our Globus.
[Marc] So, Master Ken, you think you have gotten to the secret of the landing?
[Ken] Yeah.
I think I figured out how to wire up the Globus.
It wasn't easy because they cut all the wiring for the connector, but I've been tracing stuff
out.
I've made some incomprehensible diagrams, and so I think we're ready to power it up.
So, basically the idea is there's this landing motor which will rotate the globe to the landing
position and rotate it back.
And it's a DC motor, so it needs to be able to reverse the voltage.
So, basically it has this H bridge of panel switches to control which direction the current
goes through the motor.
It has a current sink transistor here, so we get a constant current through the motor.
And then, there's a couple switches, limit switches, to tell when it's reached the landing
position and then when it goes back to the orbit position.
[Marc] Right.
So, on the little board back there, there is just the current source for the current
control for the motor.
That's the transistor, and then relays?
[Ken] Four relays, and then there's some diodes for back back flow through the relays.
[Marc] Back EMF protection.
[Ken] Yeah.
[Marc] Right.
So there is not really not that much.
[Ken] Yeah, the most interesting part I think is here.
As the globe rotates, this arm will hit this limit switch when we've reached the landing
position, and then going back, it will hit this limit switch when we get back to our
orbit position.
So, that's how it knows how far to to rotate the globe.
[Marc] Okay.
[Ken] And this one is adjusted by the front panel knob, for how far it is until you land.
So , 1A on ground, and 6A is power.
[Marc] Okay, all right.
So...
Clicky, clicky.
And then, Enable.
[Ken] And there did it!
[Marc] Oh, you were already in the (landing) mode!
[Ken] Yeah.
[Marc] Well, that's too easy!
[Ken] Now, let's switch it to the other mode.
Oh, we caught a wire there.
Works like a charm!
[Marc] Okay, let me get it from the front.
And then we got to do the landing light.
Okay, comrade, show us our landing position.
[Ken] Okay, so I'm gonna switch it to the landing position mode.
And there, it rotates ahead in the orbit.
And then, when I switch it back to Earth orbit, it rotates back.
[Marc] Amazing!
Well, that's the main function of this.
This is why they kept it for so long, it was such a good backup for this calculation.
[Ken] Yeah.
[Marc] And then, notice that we've replaced the button, because the other one was starting
to crack.
Actually, it did crack.
We repaired it, but we don't want to use the original button whenever we are working on
this.
So, should we make the indicator - actually, you can you can make the angle more...
... and have it be even more impressive.
[Ken] Okay.
So now, I switch it to landing position, and we have a big rotation.
And then, back to orbit.
[Marc] Note that the landing calculation performed by the Globus itself is very limited: you
have to manually input a value for the landing angle, which is the angle between the firing
of the retro rockets, and the landing point.
The calculation of the landing angle itself is a complicated affair, and was done by computers
on the ground.
It was then relayed to the cosmonaut, which would input it in the machine.
The Globus does not calculate it, it just displays the result - in a very beautiful
way, I might add.
[Marc] Go for it comrade!
It werks!
And indeed, it works beautifully.
There is one more thing we need to add, in order to get the full effect.
The Globus had a front light indicator, which is an electro-luminescent light, the same
technology that was used in the Apollo DSKY.
Ken figured out the relay wiring that controls the landing light, but we will have to wire
in a high voltage AC supply to make it work.
[Marc] Where do I have to connect myself?
[Ken] You want to connect to these two terminals.
[Marc] This is high voltage.
Okay, that's good.
So I'm using a little electroluminescent power supply.
and we know this is an electro-luminescent (light), so now we should have the light indication.
We got this one...
You're not landing right now, right?
[Ken] I'm in orbit mode.
[Marc] Okay, so let me...
Okay, this is the landing without the light.
[Ken] Should we test that?
[Marc] I'll test that, see if that works.
Okay.
On.
Okay, and it tells me 20 milliamps.
All right.
[Ken] Should I try to land?
[Marc] Try to land.
Hey, yeah!
[Ken] It lights up!
[Marc] We got the light!
It says, we have landed.
All right, so we have it fully working now!
[Ken] Should I leave (back to) orbit?
The light goes off!
[Marc] All right, I have the cable in the way.
All right!
Well, that's it!
So, we have the Globus fully functional, right?
It does everything it was supposed to do.
[Ken] Just those cut wires we need to solder back.
[Marc] Yeah.
So, we have to find another Globus with the correct wiring and...
[Ken] If only we knew somebody who had one or two...
[Marc] Yes! (laughter)
Redo it again, get in the landing position.
That's the main function of this, right?
That it could give you your landing position.
So it was very much a backup instrument.
Alright, so, we are almost done with the Globus.
We just need to rewire the connector, and we will be set.
[Ken] We will be in orbit!
[Marc] Now you'll land in Russia?
Barely!
You might go into China, be careful.
And also, dear unruly commenters, trying to make a point that one nation is clearly ahead
or behind by referring to this wonderful instrument, you might consider that the US had a similar
instrument in the Mercury spaceship, called the Earth Path Indicator.
Yes, there are equally brilliant engineers in all countries, coming up with similarly
brilliant solutions, and that’s what and whom we should celebrate.
And on this good note, we’ll see you in the next episode.
[Marc] And this is what it says in Russian?
Landing position?
[Ken] Something like that.
Maybe it's fasten seat belts.
(laughter)