Colour and Stereo Surface Imaging System - CaSSIS

CaSSIS

Moving Forward

Things are moving forward very rapidly but there are niggling little problems in several places. None of them would normally be big issues but ...

... they all cost the one commodity we don't have ---- time.

  • The rotation mechanism has been integrated and runs. Unfortunately it is a bit stiffer than we planned. We could reduce the pre-load but then the instrument's first resonance frequency will go down and ESA/Thales won't like that. So we are looking to improve the gearing on the motor drive.
  • The telescope is getting ready for vibration. We have an issue with the internal baffle which, when it is shaken, couples to a resonance frequency in the telescope and that is definitely not good. We might have to stiffen the internal baffle but it is not quite sure yet. The models aren't perfect and we might be OK. We find out when RUAG does a resonance search for the first time at the end of the week.
  • The focal plane assembly delivered 3 weeks ago had a small defect and needed to be exchanged. The new FPA is due here before the end of the week.
  • The oscillator which is required to work with the FPA for the read-out was found to be too slow. We dodged a bullet because getting space-qualified oscillators usually takes ages. However, we could "borrow" one from another project. It works!
  • A number of other corrections/improvements to the electronics hardware have been made. So far so good.
  • The flight PCM is running late because of delays in component soldering. Our Polish colleagues are "busting a gut" to deal with this.
  • The flight software is still not stable. It runs but there seem to be issues with the real-time operating system. The guys are working hard to debug this but it is costing us time.
  • A lot of telemetry conversion routines have been written and we can translate the HK data and the raw (uncompressed) frames from the focal plane sub-system. This seems fine so far but we need representative tests.
  • We have a widget-based tool for producing commands to the instrument ready.
  • The calibration facility is looking good. Our mirror collimator is aligned and ready. The lens collimator (which we use to verify performance when we go to the big TV chamber) has also been re-aligned by TRIOPTICS in preparation.

Whew!