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ISS computers

The ISS is the most computerized (some might say over-computerized) spacecraft yet in orbit.

Laptops

The crew interact with the onboard systems via laptops, categorized into the Portable Computer System (PCS) and Station Support Computer (SSC).

The PCS laptops provide the interface with the ship’s computer systems and runs the Solaris operating system. The SSC are used for office and personal tasks, and run a version of Windows.

Computers used in both sections are IBM ThinkPad laptops.

The ThinkPads initially on board were the 760XD model in the U.S. segment, and 760ED in the Russian segment. It has a Pentium 166 processor with 64 MB RAM, Windows 98 Second Edition and nnternet Explorer 5.5

The 760ED interfaces with Zvezda’s Control Post computer/Data Management System through an Ethernet Local Area Network, which is connected to other Russian modules and the laptops in the U.S. segment. Commands can thus be issued from any laptop in the Station.

Later in 2003, the so-called Next-Generation Laptop (an IBM ThinkPad A31P) was introduced in the American segment. This has a Pentium 4 processor and runs Windows 2000. Its expansion tray does not accept ISA cards, so the earlier 760XDs remain in use while cards are redesigned for the A31P.

The keyboards have both English and Cyrillic letters.

Four Wiener Power laptops were additionally used at Zvezda’s Command Post (TsP, ЦП) as an interface for controlling segment operations, but are being replaced by the A31P, brought up on Progress M-58 in 2006, though one WP will be kept in use as a server.

The 14 November 2007 ISS Daily Report briefly listed the Russian segment laptops:

In the RS, there are currently seven Russian computers in use: RSS1, RSS2, RSK1, RSE1, RSE-Med, TP2, and Laptop3.

This extract from Mark Shuttleworth’s training diaries at African in Space describes some of the computer software:

Lost Property for the 21st century

January 29, 2002: – No problems in Houston today. We spent the morning learning about some of the software that is installed on the US laptops in the ISS. The software is designed to help the astronauts coordinate their day, and their equipment.

The first piece of software tracks timetabling for the crew. It gives each crew member a day plan, together with supplemental information such as day/night times, S-band, Ku-band and Russian comms, procedures, equipment manifests etc. This makes it a lot easier to know what to do when. We’ll probably use this in combination with a PDA to tell me when to prepare for comms slots, when to be ready for camera work and earth observation, and when to setup and work on the science experiments.

The second piece of software, though, is a bit of a [night]mare. It’s the equipment tracking software, and it’s supposed to keep track of every plug, cap, adapter, wire, bolt, ration, camera, lens, etc on the station. There are 16 000 items in the database, the station is nearly 100 m long and packed with storage cabins, each of which is packed with STUFF. So losing track of something is very easy. In theory, this piece of software is supposed to tell us exactly where to find something, or where to put something. Everything that we move has to be logged in here.

But unfortunately, it is ssssslllllllloooooooowwwwwww. Yuri says it drove him, Shep and Sergei absolutely nuts when they were up there for increment 1. I can believe it. It took about 7 minutes just to start the app, and sometimes two or three minutes to get anything logged into the system. The handheld tracking devices that are supposed to make it easier don’t help at all.

I think this may have to do with the fact that they are running on Pentium 166 machines with 64 MB RAM, Win 98 SE, IE 5.5, and the app is a big Java app. No wonder the system grinds to a halt regularly. The fileserver has the same specs but runs NT 4. Ouch. Hopefully we’ll be able to leave the crew a present of a nice fast computer, so at least one crewmember will have rapid access to the system.

Only 64 MB RAM with all those applications running! My first computer came with this (now-measly) amount of RAM and I had to upgrade it after a few months to 256 MB as it became so sluggish. Java is also especially demanding of resources as the computer is essentially running a second operating system inside its main one when Java is opened.

And the Inventory Management System – where items are barcoded and logged into the system via a barcode reader (a system used on the Space Shuttles) – is only effective when people put items where they are supposed to be!

No Internet! Oh, the humanity!

There is no regular Internet access on the ISS as it would require high bandwidth. (Bad news for Internet addicts!) The Ku-band is the the high-bandwidth channel, but priority is reserved for data transfers such as from scientific experiments and general housekeeping (such as software upgrades from Mission Control). The crew can use email; emails are stored and forwarded to a NASA server on Earth, and vice-versa. The two servers exchange the emails in batches three times a day. Before a crewperson launches, they have to give NASA a list of the email addresses they want to receive mail from, and thus they can only receive mail from the people on this list. Anousheh Ansari updated her online blog by this method (sending entries via email).

Crews can also use Internet Phone (Voice over IP) to hold teleconferences; the secure link is via the NASA TDRSS satellites.

Hopefully that the Internet-less situation will be remedied in the future!

Data Management System

The Service Module, Zvezda, has a common onboard control complex (БКУ, BKU). This European-Russian designed system, linked by integrated control algorithms, is a network that co-ordinates all the Russian segment’s systems to perform the Station’s tasks. The БКУ’s components are:

  • The onboard computer system (БВС, BVC)
  • Onboard hardware control system (СУБА, SUBA)
  • Motion control and navigation system (СУДН, SUDN).

The БКУ also interacts with the onboard data telemetry system and radio technical facilities.

The European Space Agency and Energiya jointly developed the Russian segment’s БКУ (or Data Management System, DMS, as ESA calls it). This is described on a page at the ESA website:

The DMS-R, installed in the Russian Service Module Zvezda, is the set of on-board computers, their avionics and software that provide for the overall control, mission and failure management of the entire Russian segment of the ISS.

The DMS-R performs functions such as:

  • guidance, navigation and control for the entire ISS,
  • on-board systems and subsystems control,
  • mission management with supervisory control by the on-board and ground crews,
  • failure management and recovery,
  • time distribution, time tagging and synchronisation,
  • data acquisition and control for on-board systems and experiments
  • exchange of data and commands with the other parts of the ISS

The ESA-provided on board units are:

  • 2 Fault Tolerant Computers: a Control Computer and a Terminal Computer
  • 2 Control Posts for command and control by the crew, for commanding experiments and ERA

The DMS-R has been developed by ESA with an industrial team lead by ASTRIUM (Bremen, Germany).

The application software for the on-board computers has been developed by the Russian Zvezda contractor, RSC Energiya, using an ESA-provided ground system – the hardware and software environment supporting software design, development, simulation, test and validation.

The Russian Service Module, with the ESA-developed D-MSR, was successfully launched in July 2000, and is working nominally since then.

The Russian segment has several “modes” under which it operates, depending upon the situation:

  1. Standard. This supports such RS modes as fuel transfer (from Progress to storage tanks in Zvezda) and gyrodine spin-up modes (the gyrodines keep the RS and ISS stabilized).
  2. Reboost (orbit correction by means of Progress or Zvezda thrusters).
  3. Proximity operations (docking, undocking, redocking).
  4. ВКД/EVAs (spacewalks).
  5. Microgravity. Support of onboard experiments and general daily life.
  6. Survival. This ISS mode supports the Russian Segment initial attitude mode so as to provide normal power supply.
  7. Assured safe crew rescue. In the event of depressurization of the RS, fire or toxins released into the atmosphere.

Diagrams

~ Page last updated: 14 November 2007

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Photo gallery

Sergei & Yurii using laptop (NASA)

Sergei Krikalyov and Yurii Gidzenko (ISS-1) input data into a Wiener Power computer.

JSC-ISS teleconference (NASA)

Screenshot of a teleconference between JSC and the ISS, using Voice over Internet Protocol (Internet Phone). The software used is Microsoft NetMeeting.