Software for the International Space Station

There are a number of applications which are being used or developed for the International Space Station. This page will essentially repeat the article which was published at page 74 of the March issue of the Linux Journal. There are many people in the UK who are not able to get hold of the Linux Journal. This will help them to be more up to date.

There are a few applications which are being developed for use with the ISS. RACSI and GOAS are discussed here.

RACSI is a laptop application which can be used inside the ISS by an astronaut to control the docking of the ATV pre-development program. The screen shot here shows how the laptop screen looks. RACSI screens are viewed in three areas. Mission display (mission phase, transitions), the main display (trajectory) and messages (messages and warnings). ATV stands for ATV RendezVous Pre-development or ARP program. This is all about design, development and prototype products for use in space. The first demo was trialled on the STS-80 Shuttle. RACSI was originally developed on Linux Slackware with a 2.0.30 kernel. This was to be used and is used on an IBM ThinkPad. RACSI was programmed in ANSI C. It uses the Moo-Tiff libraries from InfoMagic. A desktop version has also been tried with SuSE 5.2 and kernel 2.0.33. The RACSI interface processes make use of APIs. There are several modules inside the software which are...... a telemetry handler, mission and vehicle monitoring, failure detection and assessment, display management and a telecommand handler.

The docking of a chaser spacecraft (ATV) with a larger craft (ISS) is not as simple as it may seem. The calculations that have to be made are complex. Therefore the forecasting of failures is helpful for the success of the mission. RACSI provides two options which are essentially to temporarily interrupt the mission or to try to implement a collision avoidance manoeuvre. The RACSI data management scheme can be seen in the diagram to the left here. You can also see a simple graphical explanation of ATV docking below.

GOAS or Ground Operator Assistant System is the part of the system that runs on the ground. Ultra Sparc 5 machines are used with 64Mb of RAM and 300Mb of disc space. X-windows is used under Solaris. This was the system that was first used. A Linux GOAS system has been developed on a 233Mhz Pentium system with 48Mb of RAM. X-windows and a mouse are used with this although operators are allowed to see AND use a keyboard. GOAS is similar to the RACSI software but it's also a bit more complex.

If you would like more information on RACSI and GOAS and the other projects that the ESA are working on please click on the links. If you want to send e-mail to the ESA you can find the appropriate addresses at their site.