SMART-1 Status Report October 6, 2003

After more than 32 hours of accumulated thrust, the SMART-1 electric
propulsion system (EPS), with a SNECMA PPS-1350-G Hall-Effect
thruster, is now fully tuned for nominal operations under space conditions.

The thruster performance and discharge stability are very good and confirmed by
the measurements of total spacecraft acceleration over an orbit. As planned, the
EPS commissioning had started during the fourth orbit with a venting sequence of
the xenon subsystem in order to eliminate any presence of water vapour and
oxygen. Then a first firing sequence of 50 minutes was completed successfully
with the nominal cathode followed by a 6 minutes sequence at full power on the
redundant one. This sequence was interrupted by discharge flame out after the
thruster had remained in a high oscillation mode. After a complete electrical
check
of the system, the thruster was fired successfully on the primary cathode for
2.5
hours.

The start-up sequence has been optimized to limit these oscillation
effects and the actuation logic of the pressure regulation improved in order
to avoid current and voltage overshoots. These improvements have
been made possible because of the specific SMART-1 characteristics of
the EPS to be able to modulate the power and the xenon flow with simple
telecommands. Since then, some 29 hours of continuous thrust have
increased the orbit semi-major axis by some 300 kilometres with some 300 g
of xenon consumed.

Finally, with the help of the EPDP (Laben, Italy) and SPEDE (FMI, Finland)
payload instruments, a lot of new information to be further processed and
analysed is being acquired on the possible effects of the space environment on
some typical EPS characteristics as experienced during ground testing. The
SMART-1 mission plays perfectly its role of technology demonstration mission in
the space environment and will strongly contribute to the acceptance of electric
propulsion as a fully mature and flight-proven technology.