Writing a short film - need help with technicalities!

[-ctn-]

Hello everyone! I think this is the right spot for this thread. If not, feel free to move it or direct me.

Anyways, I'm a film school graduate and aspiring filmmaker, and since becoming obsessed with KSP and space, I wanted to try to develop a short film about space.

The concept is a twilight-zone type story onboard the ISS. While there are some sci-fi type elements, I wanted to keep it realistic; in my research I've failed to answer a few of my questions, and I hoped I could get them answered here.

Onboard the ISS, is there any center-control console? A command pod, if you will, the controls the entire craft. Or does each module have it's own airlock, pressure, ect. controls?

Is every module equipped with RCS? If they are, how are they controlled? Via the aforementioned control center or separately?

If the ISS lost contact with Mission Control and/or earth in general, would any systems shut down? Is anything controlled from the ground here?

Is there a central docking station for arriving spacecraft or are there several docking ports scattered along the entire craft?

[tater]

I'd suggest starting out with the wiki pages on ISS. I think the control computers are in Zvezda (the Service Module), and they prefer to use a Progress for lifting the orbit (they have to do this periodically because of atmospheric drag---in Kerbal universe, it's like they are orbiting at 69,999 m, there is a little drag).

[-ctn-]

I did try to read through all the wiki pages but it must have gone over my head or my eyes got lost in the text.

I'll give it another go around - although I did NOT know that they have to periodically lift the orbit. That's interesting...

[hugix]

The ISS has no RCS but used gyroscopes to stay orientated.

If there is a loss of signal I doubt that the ISS would shut down systems as there are still people on board using those systems.

the ISS has a couple of PMA ( http://en.wikipedia.org/wiki/Pressurized_mating_adapter ) ports spread out on the ISS. I'm not sure if Soyuz uses the same adapter.

Edited January 6, 2015 by hugix

[Nibb31]

Onboard the ISS, is there any center-control console? A command pod, if you will, the controls the entire craft. Or does each module have it's own airlock, pressure, ect. controls?

Most of the ISS systems are controlled by various laptops that are located around the station. Each laptop can access all systems. The closest you'll find to a "cockpit" is the Cupola module, which is a wide window bay that is used for observation, monitoring docking/berthing operations and simply daydreaming...

Manoeuvers such as rotation, reboost or avoidance, are usually scheduled and controlled from the ground.

There are two airlocks on the ISS: The Quest airlock module on the USOS and the Pirs module on the Russian segment. The spherical parts on the Zarya and Zvezda (where the other modules dock) can and have been used as airlocks, in contingency situations.

Is every module equipped with RCS? If they are, how are they controlled? Via the aforementioned control center or separately?

Only the Russian modules Zvezda and Zarya have RCS, but I don't think those are functional any more. Those modules were essentially individual spacecraft that could fly and dock independantly. That is not the case with USOS modules (US Orbital Segment, including European and Japanese modules), which are basically dumb canisters.

Attitude control is done through CMG (control moment gyroscopes), located in the truss. These are basically a set of heavy flywheels that spin up and down on several axes, which rotates the station in the opposite direction. Reboost is done by visiting craft (Progress or ATV).

If the ISS lost contact with Mission Control and/or earth in general, would any systems shut down? Is anything controlled from the ground here?

No, systems are redundant. It would be pretty hard to actually lose contact with Mission Control though. Comms go through redundant channels, including the TDRS satellites and ground stations around the world. Each country has independant communication channels and mission control centers. The USOS and global systems are controlled from Houston, but the international modules have their own Mission Control centers in Russia, Europe, and Japan. If one channel was to go down, communications would go through someone else's module.

Is there a central docking station for arriving spacecraft or are there several docking ports scattered along the entire craft?

There are lots of docking ports, using different systems. The Russian segment has at least 3 hybrid docking ports for visiting Soyuz and Progress vehicles. At least two of those are constantly used by 2 Soyuz spacecraft that also serve as lifeboats in case of emergency. The USOS has 2 APAS ports which were used by the Shuttle, and are soon to be equipped with IDS adapters (the new international standard) for CST-100 and Dragon. And there are several CBM ports, which can't be used for docking, but allow visiting vehicles to be berthed with the robotic arm (for Dragon and Cygnus) or new modules to be attached.

Edited January 7, 2015 by Nibb31

[Kryten]

Only the Russian modules Zvezda and Zarya have RCS, but I don't think those are functional any more. Those modules were essentially individual spacecraft that could fly and dock independantly. That is not the case with USOS modules (US Orbital Segment, including European and Japanese modules), which are basically dumb canisters.

I know one of these has functional thrusters and can be used for ISS reboost between Progress visits; I strongly suspect it's Zvezda, although I don't know for certain.

There are lots of docking ports, using different systems. The Russian segment has at least 3 APAS ports for visiting Soyuz and Progress vehicles, and maybe some old probe and drogue docking ports between modules. 2 Soyuz are constantly docked and serve as lifeboats in case of emergency. The USOS has 2 APAS ports which were used by the Shuttle, and are soon to be equipped with IDS adapters (the new international standard) for CST-100 and Dragon. And there are several CBM ports, which can't be used for docking, but allow visiting vehicles to be berthed with the robotic arm (for Dragon and Cygnus) or new modules to be attached.

Probe-and-drogue is standard on the ROS, no Russian vehicle has actually used APAS since the Soyuz' built for ASTP (although Buran was designed to).

[-ctn-]

Nibb31, that was extremely helpful. Thank you!

Does anyone know what the standard procedure would be if comms went down across all channels? As far fetched as that may be, it's obviously a big part of this story idea.

[Nibb31]

Nibb31, that was extremely helpful. Thank you!

Does anyone know what the standard procedure would be if comms went down across all channels? As far fetched as that may be, it's obviously a big part of this story idea.

They would probably try to troubleshoot the problem and wait for ground teams to reestablish comms. Visiting vehicles also have their own independant and redundant comm systems, so they would probably power up the Soyuz and try using that. They might try juryrigging their gear to contact HAM radios or something. If nobody answers, then I guess Earth is toast.

If the situation became untenable or dangerous (lack of attitude control, supplies, or critical information), then I suppose the decision would be made to evacuate. For example, after a while it might be risky to stay on board without debris monitoring information.

I know one of these has functional thrusters and can be used for ISS reboost between Progress visits; I strongly suspect it's Zvezda, although I don't know for certain.

It probably is. Firing thrusters on Zarya would result in a bad day for Zvezda. I don't thing they use its RCS pods though. They spend a lot of effort trying to minimize pollution from thruster exhaust in the vicinity of the ISS.

Probe-and-drogue is standard on the ROS, no Russian vehicle has actually used APAS since the Soyuz' built for ASTP (although Buran was designed to).

Yes, you're right. In fact it's called "hybrid", a probe and drogue system with an APAS docking collar.

Edited January 7, 2015 by Nibb31

[tater]

I know one of these has functional thrusters and can be used for ISS reboost between Progress visits; I strongly suspect it's Zvezda, although I don't know for certain.

I believe this is correct, they put a Progress on the back of Zvezda, and that points along the long-axis of ISS (which nominally points in the direction of the velocity vector as I understand it)

[LordFerret]

As far as the Comms are concerned, I do believe they've got triple backup of everything (2 functional, 1 as spare/parts). They even have ham radios onboard ... ham operators (ARRL) have contests sort of, which they make contact with the astronauts and obtain QSL cards ... and there's a large cooperative program (education) between NASA & ARRL.

http://www.arrl.org/amateur-radio-on-the-international-space-station

Losing Comms with the ISS is the very least of problems they face. They've access to just about every band imaginable - plus a few you and I have no access or availability to equipment for.