a mechanical navigation laptop for Soviet spaceflight
The Soviet house program used utterly completely different controls and devices from American spacecraft.
One of the crucial fascinating navigation devices onboard Soyuz spacecraft was the Globus, which used a rotating globe
to point the spacecraft’s place above the Earth.
This navigation instrument was an electromechanical analog laptop that used an elaborate system of gears, cams, and differentials
to compute the spacecraft’s place.
Formally, the unit was known as a “house navigation indicator” with the Russian acronym ИНК (INK),1
however I will use the extra descriptive nickname “Globus”.
The INK-2S “Globus” house navigation indicator. Coincidentally, the latitude indicator matches the Ukrainian flag.
We just lately obtained a Globus from a collector and opened it up for restore and reverse engineering.
On this weblog put up, I clarify the way it operated, present its inside mechanisms, and describe what I’ve discovered so removed from
reverse engineering.
The photograph beneath offers an thought of the mechanical complexity of this system, which additionally has just a few relays, solenoids, and different electrical
parts.
Aspect view of the Globus INK. Click on this (or another picture) for a bigger model.
Performance
The first goal of the Globus was to point the spacecraft’s place. The globe rotated whereas fastened crosshairs on the
plastic dome
indicated the spacecraft’s place.
Thus, the globe matched the cosmonauts’ view of the Earth, permitting them to verify their location.
Latitude and longitude dials subsequent to the globe offered a numerical indication of location.
In the meantime, a light-weight/shadow dial on the backside confirmed when the spacecraft could be illuminated by the solar or in shadow,
necessary data for docking.
The Globus additionally had an orbit counter, indicating the variety of orbits.
The Globus had a second mode, indicating the place the spacecraft would land in the event that they fired the retrorockets to
provoke a touchdown. Flipping a change precipitated the globe to rotate till the touchdown place was below the crosshairs
and the cosmonauts might consider the suitability of this touchdown website.
The cosmonauts configured the Globus by turning knobs to set the spacecraft’s preliminary place and orbital interval.
From there, the Globus electromechanically tracked the orbit.
Not like the Apollo Steering Pc, the Globus didn’t obtain navigational data from an inertial measurement unit (IMU) or different sources, so it didn’t know the spacecraft’s actual place.
It was purely a show of the expected place.
A detailed-up of the advanced gear trains within the Globus.
The globe
The globe itself is detailed for its small measurement, exhibiting terrain options equivalent to mountains, lakes, and rivers.
These options on the map helped cosmonauts examine their place with the geographic options they may
see on Earth.
These options have been additionally necessary for choosing a touchdown website, so they may see what sort of terrain they’d
be touchdown on.
For probably the most half, the map would not present political boundaries, aside from thick pink and purple strains.
This line exhibits the borders of the USSR, in addition to the boundaries between communist and non-communist nations,
additionally necessary for choosing a touchdown website.
The globe additionally has numbered circles 1 by means of 8 that point out radio websites for communication with the
spacecraft, permitting the cosmonauts to find out what floor stations may very well be contacted.
A view of the globe exhibiting Asia.
Controlling the globe
On seeing the Globus, one may marvel how the globe is rotated.
It could appear that the globe have to be free-floating so it may rotate in two axes.
As a substitute, a intelligent mechanism attaches the globe to the unit.
The secret is that the globe’s equator is a strong piece of metallic that rotates across the horizontal axis of the unit.
A second gear mechanism contained in the globe rotates the globe across the North-South axis.
The 2 rotations are managed by concentric shafts which can be fastened to the unit, permitting two rotational levels of freedom by means of fastened shafts.
The photograph beneath exhibits the body that holds and controls the globe.
The dotted axis is fastened horizontally within the unit and rotations are fed by means of the 2 gears on the left.
One gear rotates the globe and body across the dotted axis, whereas the gear prepare causes the globe to rotate across the
vertical polar axis (whereas the equator stays fastened).
The axis of the globe is at 51.8° to assist that orbital inclination.
The angle above is 51.8° which is essential: that is the inclination of the usual Soyuz orbit.
Consequently, merely rotating the globe across the dotted line causes the crosshair to hint the usual orbit.2
Rotating the 2 halves of the globe across the poles yields the completely different 51.8° orbits over the Earth’s floor
because the Earth rotates.
(Why 51.8 levels? The Baikonur Cosmodrome, launching level for Soyuz, is at 45.97° N latitude, so 45.97° could be
probably the most environment friendly inclination.
Nevertheless, to forestall the launch from passing over western China, the rocket have to be angled in direction of the north,
leading to 51.8° (details).)
One necessary consequence of this design is
that the orbital inclination is fastened by the angle of the globe mechanism. Totally different Globus models
wanted to be constructed for various orbits.
Furthermore, this design solely handles round orbits, making it ineffective throughout orbit modifications equivalent to rendezvous and docking.
These have been such vital limitations that some
cosmonauts wished the Globus faraway from the management panel, nevertheless it remained till it was changed by a pc show in Soyuz-TMA (2002).3
A closeup of the gears that drive the movement of the 2 halves of the globe across the polar axis, leaving the equator fastened.
This Globus had clearly suffered some injury.
The again of the case had some giant dents.7
Extra importantly, the globe’s shaft had been knocked free from its correct place and now not meshed with the gears.
This additionally put a gouge into Africa, the place the globe hit inside parts.
Fortuitously, CuriousMarc was in a position to get the globe again into place whereas guaranteeing that the gears had the suitable timing.
(Placing the globe again arbitrarily would mess up the latitude and longitude.)
Orbital velocity and the “cone”
An orbit of Soyuz takes roughly 90 minutes, however the time varies in line with altitude.4
The Globus has an adjustment knob (beneath) to regulate
the orbital interval in minutes, tenths of minutes, and hundredths of minutes.
The outer knob has three positions and factors to the digit that modifications when the inside knob is turned.
The mechanism offers an adjustment of ±5 minutes from the nominal interval of 91.85 minutes.3
The management to regulate the orbital interval.
The orbital velocity characteristic is carried out by growing or lowering the velocity at which the globe rotates across the orbital (horizontal)
axis.
Producing a variable velocity is hard, because the Globus runs on fastened 1-hertz pulses.
The answer is to start out with a base velocity, after which add three increments: one for the minutes setting, one for
the tenths-of-minutes setting, and one for the hundredths-of-minutes setting.5
These 4 speeds are added (as shaft rotation speeds) utilizing acquire the general rotation velocity.
The Globus makes use of quite a few differential gears so as to add or subtract rotations. The photograph beneath exhibits two units of
differential gears, side-by-side.
Two differential gears within the Globus.
The issue is how you can generate these three variable rotation speeds from the fastened enter.
The answer is a particular cam, formed like a cone with a spiral cross-section.
Three followers experience on the cam, in order the cam rotates, the follower is pushed outward and rotates on its shaft.
If the follower is close to the slim a part of the cam, it strikes over a small distance and has a small rotation.
But when the follower is close to the extensive a part of the cam, it strikes a bigger distance and has a bigger rotation.
Thus, by shifting the follower to a selected level on the cam, the rotational velocity of the follower is chosen.
A diagram exhibiting the orbital velocity management mechanism. The cone has three followers, however solely two are seen from this angle. The “transmission” gears are moved out and in by the outer knob to pick out which follower is adjusted by the inside knob.
Clearly, the cam cannot spiral out eternally.
As a substitute, on the finish of 1 revolution, its cross-section drops again sharply to the beginning diameter.
This causes the follower to snap again to its authentic place.
To forestall this from jerking the globe backward, the follower is linked to the differential gearing by way of a slip clutch and ratchet.
Thus, when the follower snaps again, the ratchet holds the drive shaft stationary.
The drive shaft then continues its rotation because the follower begins biking out once more.
Thus, the output is a (largely) easy rotation at a velocity that relies on the place of the follower.
Latitude and longitude
The symptoms on the left and the highest of the globe point out the spacecraft’s latitude and longitude respectively.
These are outlined by surprisingly advanced features, generated by the orbit’s projection onto the globe.6
The latitude and longitude features are carried out by means of the form of metallic cams; the photograph beneath exhibits the
longitude mechanism.
Every operate has two cams: one cam implements the specified operate, whereas the opposite cam
has the “reverse” form to take care of pressure on the jaw-like monitoring mechanism.
The cam mechanism to compute longitude.
The latitude cam drives the latitude dial, inflicting it to oscillate between 51.8° N and 51.8° S.
Longitude is extra difficult as a result of the Earth’s rotation causes it to continually fluctuate.
The longitude output on the dial is produced by including the cam’s worth to the Earth’s rotation by means of a differential gear.
Gentle and shadow
The Globus has an indicator to indicate when the spacecraft will enter gentle or shadow.
The dial consists of two concentric dials, configured by the 2 knobs.
These dials transfer with the spacecraft’s orbit, whereas the pink legend stays fastened.
I believe these dials are geared to the longitude dial, however I am nonetheless investigating.
The sunshine and shadow indicator is managed by two knobs.
The touchdown location mechanism
The Globus can show the place the spacecraft would land in the event you began a re-entry burn now, with an accuracy
of 150 km.
That is computed by projecting the present orbit ahead by a partial orbit, relying on how lengthy it could take to land.
The cosmonaut specifies this worth by the “touchdown angle”, which signifies this fraction of an orbit as an angle.
An electroluminescent indicator within the upper-left nook of the unit exhibits “Место посадки” (Touchdown place) to point this mode.
The touchdown angle management.
To acquire the touchdown place, a motor spins the globe till it’s stopped after rotating by means of the required angle.
The mechanism to implement that is proven beneath.
The adjustment knob on the panel turns the adjustment shaft which strikes the restrict
change to the specified angle by way of the worm gear. The wiring is wrapped round a wheel so the wiring stays managed throughout this motion.
When the drive motor is activated, it rotates the globe and the swing arm on the similar time.
Because the motor stops when the swing arm hits the angle restrict change, the globe rotates by means of the specified angle.
The fastened restrict change is used when returning the globe’s place to its common, orbital place.
The touchdown angle operate makes use of a fancy mechanism.
The touchdown location mode is activated by a three-position rotary change. The primary place
“МП” (место посадки, touchdown website) selects the touchdown website, the second place “З” (Земля, Earth) exhibits the place over the Earth, and the third place “Откл” (off) undoes the touchdown angle rotation and turns off the mechanism.
The rotary change to pick out the touchdown angle mode.
Electronics
Though the Globus is generally mechanical,
it has an electronics board with 4 relays and a transistor, in addition to resistors and diodes.
I believe that the majority of those relays management the touchdown location mechanism, driving the motor ahead or
backward and stopping on the restrict change.
The diodes are flyback diodes, two diodes in collection throughout
every relay coil to eradicate the inductive kick when the coil is disconnected.
The electronics circuit board.
A 360° potentiometer (beneath) converts the spacecraft’s orbital place right into a voltage. Sources point out that
the Globus offers this voltage sign to different models on the spacecraft.
My principle is that the transistor on the electronics board amplifies this voltage, however I’m nonetheless investigating.
The potentiometer converts the orbital place right into a voltage.
To the suitable is the cam that produces the longitude show. Antarctica is seen on the globe.
The photograph beneath exhibits the a number of wiring bundles within the Globus, on the entrance and the left. The electronics board is on the entrance proper.
The Globus incorporates a stunning quantity of wiring for a tool that’s largely mechanical.
Inconveniently, all of the wires to the field’s exterior connector (higher left) have been lower.7
Maybe this was a part of decommissioning the unit.
Nevertheless, one of many screws on the case is roofed with a tamper-resistant wax seal with insignia, and this
wax seal was intact.
This means that the unit was formally re-sealed after chopping the wires, which does not make sense for
a decommissioned unit.
This view exhibits the again and underside of the Globus. The spherical connector on the again left offered the interface with the remainder of the spacecraft. The black wires below this connector have been all lower.
The unit is pushed by two ratchet solenoids: one for the orbital rotation and one for the Earth’s rotation.
These solenoids take 27-volt pulses at 1 hertz.3
Every pulse causes the solenoid to advance the gear by one tooth; a pawl retains the gear from slipping again.
These small rotations drive the gears all through the Globus and end in a tiny motion of the globe.
One of many driving solenoids within the Globus. The wheels to point orbital time are beneath.
The opposite driving solenoid within the Globus.
Apollo-Soyuz
Should you look intently on the globe, it has a bunch of pink dots added, together with three-letter labels in Latin (not Cyrillic) characters.8
Within the photograph beneath, you’ll be able to see GDS (Goldstone), MIL (Merritt Island), BDA (Bermuda), and NFL (Newfoundland).
These are NASA monitoring websites, which suggests that this Globus was constructed for the Apollo-Soyuz Take a look at Challenge,
a 1975 mission the place an Apollo spacecraft docked with a Soyuz capsule.
North America because it seems on the globe. The US border is marked in pink. The number of cities appears a bit random, equivalent to El Paso as the one western metropolis till the coast.
Additional affirmation of the Apollo-Soyuz connection is the VAN sticker in the course of the Pacific Ocean (not seen above).
The USNS Vanguard was a NASA monitoring ship that was used within the Apollo program to fill in gaps in radio protection. It was an oil tanker from World Warfare II, transformed postwar to a missile
monitoring ship after which used for Apollo. Within the photograph beneath, you’ll be able to see the big monitoring antennas on its deck.
In the course of the Apollo-Soyuz mission, Vanguard was stationed at 25 S 155 W for the Apollo-Soyuz mission, precisely matching
the situation of the VAN dot on the globe.
Historical past
The Globus has a protracted historical past, again to the beginnings of Soviet crewed spaceflight. The primary model was less complicated and had the Russian acronym ИМП (IMP).9
Growth of the IMP began in 1960 for the Vostok (1961)
and Voshod (1964) spaceflights.
The fundamental features of the sooner Globus IMP are just like the INK, exhibiting the spacecraft’s place and the
touchdown place.
It has an orbit counter within the decrease proper. The latitude and longitude shows on the prime have been added for the Voshod flights.
The big correction knob
permits the orbital interval to be adjusted.
The primary variations are that the IMP would not have a show on the backside for solar and shade and
would not have a management to set the touchdown angle.9
Not like the INK, the mode (orbit vs touchdown place) was chosen by exterior switches, relatively than a change on the unit.
The extra advanced INK mannequin (described on this weblog put up) was created for the Soyuz flights, beginning in 1967.
It was a part of the “Sirius” data show system (IDS).
The Neptun IDS used on Soyuz-T (1976) and the Neptun-M for Soyuz-TM (1986) modernized a lot of the console however saved the
Globus INK. The photograph beneath exhibits the Globus mounted within the upper-right of a Soyuz-TM console.
The Soyuz-TMA (2002) upgraded to the Neptun-ME system3 which used digital show screens. Particularly, the Globus was changed with the graphical show beneath.
Conclusions
The Globus INK is a outstanding piece of equipment, an analog laptop that calculates orbits by means of an intricate
system of gears, cams, and differentials.
It offered cosmonauts with a high-resolution, full-color show of the spacecraft’s place, method past what
an digital house laptop might present within the Sixties.
Though the Globus is an incredible piece of mechanical computation, its performance is proscribed.
Its parameters have to be manually configured: the spacecraft’s beginning place, the orbital velocity, the sunshine/shadow areas, and the touchdown angle.
It would not take any exterior steerage inputs, equivalent to an IMU (inertial measurement unit), so it is not significantly correct.
Lastly, it solely helps a round orbit at a hard and fast angle.
Whereas the extra fashionable digital show lacks the bodily appeal of a rotating globe, the digital resolution offers
way more functionality.
I plan to proceed reverse-engineering the Globus and hope to get it operational,
so observe me on Twitter @kenshirriff or RSS for updates.
I’ve additionally began experimenting with Mastodon just lately as @[email protected].
Many due to Marcel for offering the Globus.
Because of Stack Overflow for orbit data and my Twitter followers for translation help.
I ought to give a disclaimer that I’m nonetheless reverse-engineering the Globus, so what I described is topic to vary.
Additionally, I do not learn Russian, so any errors are the fault of Google Translate. 🙂
With the case eliminated, the advanced internals of the Globus are seen.