Mars-96

The Mars-96 space probe was planed to be launched at 16 November 1996 for studying the environment and the surface of Mars. Due to our field of interest we were particularly interested in examining interaction between the planet and solar wind. The Mars-96 launch was unsuccesfull. Spacecraft has landed into Pacific ocean after few hours.

We had been participating in completing three different experiments, which could be realized with relatively low financial effort using our wide experience in this field we gained before. The first equipment (MAREMF) studies the distribution of electrons around Mars, the magnetic field of Mars and the interaction between electrons and magnetic field. The MARIPROB experiment will be examining the parameters of ionosphere of the planet, while the third experiment (SLED-2) the high energy particles of the environment of Mars.

EGSE for the Mars-96 plasma complex

In case of the MAREMF and MARIPROB experiments our task is the development and manufacture of the Electrical Ground Support Equipment (EGSE). The EGSE provides checking of the given scientific equipment during Autonomous, System (integration) and Complex Tests and gives the possibility of a quick look at the data during tests or flight. Due to this, the EGSE remains in function continuously after launch, to provide quick process of scientific or housekeeping data during flight.

The EGSE has the following main functions:

Simulation of the onboard signals of the Mars 96 Space Probe (The Morion-S system, that is, ControlCommandWords, Onboard Time, Telemetry Signals and Power Lines)
Coding and archiving of acquired data
Evaluating of the experiment functionality based on the acquired data
Process and visualization of the scientific data

The tasks listed above need certain computing capability, so the core of the system is a general purpose computer, extended by the necessary special-purpose interface units. For low-budget reasons this system core is an IBM PC or compatible, and it is extended by the following interface units to form a EGSE:

Control Command Word (CCW) simulator
OnBoard Time code simulator
Digital Telemetry simulator
Analog Telemetry simulator
On/Off Switch Relay Command simulator
Power System Simulator
Data-Distribution interface

The operating software is based on a custom-designed real-time quasi-multitask Operation System written in Turbo Pascal. In this system Tasks are serviced in three level:

The most frequent event is data acquisition through Direct Memory Access - this method consumes the least processor time
Real Time system control&timing and asynchronous service of Operator commands through Interrupts, which method causes the least slip in service time
Data processing and displaying runs in the background.

For the two experiments (MAREMF and MARIPROB) altogether four fully implemented EGSE systems are needed, these are basically similar. The only difference between them is in the connection cables and operating software.

For SLED-2 experiment the development of the on-board Operation System is our task. We also have here tasks in the design of the experiments and in the preparations for the scientific data evaluation. Our contribution to this project was the implementation of the system software, which we had developed for our previous projects. The repeated utilization of it helped us to keep the costs at a minimal level.

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Comments to Pál VIZI p.vizi@rmki.kfki.hu

Contact to Sándor SZALAI szalai@rmki.kfki.hu