Basic information about CaSSIS can be found at www.cassis.unibe.ch which includes a news site. A brief description about the mission and the instrument can be found in www.cassis.unibe.ch/instrument
A full instrument description is provided in Thomas et al. (2017) (link.springer.com/article/10.1007/s11214-017-0421-1).
The European Space Agency web page for the spacecraft can be found at www.esa.int/Science_Exploration/Human_and_Robotic_Exploration/Exploration/ExoMars/Trace_Gas_Orbiter_instruments
The raw data can also be found at the Planetary Science Archive of the European Space Agency at https://archives.esac.esa.int/psa/#!Table%20View/CaSSIS=instrument
The PSA forms the formal repository for CaSSIS data. The raw data here are identical to the data submitted to PSA for publication. The geometrically rectified and corrected data on this site are published in advance of delivery to the PSA and sometimes prior to review. This may mean that header information can change if (for example) something is established to be incorrect (e.g. not compatible with the PDS V4 standard). However, we do our best to ensure that this is as close to final as our knowledge allows.
Our data complements that of HiRISE and you are referred to www.uahirise.org/catalog for HiRISE data.
Other points
Our data have two names – the MYxx form you see here applies to the final products. The other name (which includes the framelet acquisition time) is used for the raw at lower levels of processing and is needed to keep track of framelets in the telemetry conversion process. For geometrically corrected data, you do not need this lower level – the MYxx format should be sufficient.
Our data can be taken at many different local solar times including close to or even beyond the terminators. In some cases this can result in very low signal to noise. ALL data are available on the web site so you will see these images if you scroll through the full data set. CaSSIS is a high SNR instrument and so some images up to 87 degrees illumination angle can still be useful. However, this strongly depends on the dust load. High optical depths result in poor images. In particular, low signal to noise can result in poorer colour alignment and evidence of colour fringing. We have put a lot of effort into trying to optimise/improve registration. However, there are limits. Consequently, dusty or poorly illuminated images should be checked visually.
Images were taken during dust storms. These data often do not show the surface at all (optical depth >> 1). These are useless for surface studies but may have some interest for atmospheric physicists.
Some images were acquired with the rotation mechanism poorly aligned to the ground track. These data are in the database but are probably of little interest. Perfect alignment shows no jagged edges to the image. Images misaligned by up to 30 deg are normally useful.
Some images (especially with poor SNR) might show some linear structure. This is a consequence of residual straylight in the system (probably a spurious reflection from a field stop). Unfortunately this straylight is variable and depends upon the phase of Mars at the position of the spacecraft when imaging. Our automated tools are close to the limit of what can be achieved. Individual analysis may provide slightly cleaner data but the errors are small and only revealed in low SNR data. If you really, really need exactly that image, please contact us.