Today I will talk about one thing that nobody notices and few people think when they see science fiction movies and is about the links between vehicles.
Although I told a little when talking about the MIR, when you see a movie and two ships of two different civilizations are coupled by hatches without any problems and even two ships (of the same civilization) are achieved coupled as usual. Is no one has thought that everyone can have a coupling system as you leave down there ?. And moreover, how they are supported when no two are alike no screws or two plugs of two equal countries?.
Well, in 1972 (if I’m not mistaken) it was the first time that Russians and Americans met to agree about how to create a system common anchor (docking) spacecraft since each, for now, in his few attempts, I was a little to his ball. As a model, for its versatility and efficiency, the Russian model was taken as a reference, creating the APAS-75 or version 75 which was the first time a Soyuz and Apollo joined.
Mainly there are two types of models, androgynous and not androgynous. Androgynous are like plugs, there is a male and a female, unable acolparse two of the same sex. However non androgynous are male / female both, may act one way and another as needed.
Other than that, they had to agree on the measures the hole (if, through which people or goods) because, well, there are different models.
The case is that it has created an international agency caring (and has open) the anchoring system so that at least all terrestrial ships, are compatible. Another story is that the implementation of each country whatever it wants because the anchoring system is “engaged in business” and already known.
In fact, it’s standard is under review because now not only want to dock ships but also want to transfer oxygen, water and fuel including considering now, problems that not all ships use the same pressures, same fuels or even air concentrations. And in that, there is much to stick with that.
The current model is called the IDSS (International Docking System Standard) having adapters (IDA International Docking Adapter) for specifications concrete APAS-95 (Russian), NDS (Nasa Docking System) and the IDSS. Which the ISS is well nourished (curiously). Incidentally, the Chinese system (know that will create its own space station) is a copy of the APAS-95 literal Russian.
Regarding docking procedures, there are several standards to make it all easier. As planes have their highways and procedures or standard takeoffs and landing, space vehicles also.
Without going too much into details, unless you play in the Kerbal Space Program (which can simulate), two-time procedure orbit approach (with the letters A and B) which vary if visual contact with the target; two close approximation procedures (A and B) depending on the distance and a single shunting coupling.
By physical, methods of approach and because of orbits (elliptical) is made can be performed either behind accelerating (approximation in V called) ahead braking (approximation R) or at the same speed in parallel orbits where horizontally (so we understand, so-called approximation Z, Z axis are) we move.
The name of each of the names, depends on the approach vector you want to keep, so the V is the velocity vector (remember that accelerating changes orbit is more eccentric), the R is a radial approach and consuming less fuel is always preferred and the Z axis as both are at the same speed.
Easy they are mechanics 101 of physics and this is a PDF that I recommend reading this topic if you like.