During RP3, significant advancements were in the MAX-FRESH project enhancing system performance and reliability.
Three mid-infrared supercontinuum lasers with a total average power of ~450mW, tailored for ISS monitoring systems, were built, tested, and delivered to RU. During RP3, their spectral densities were optimized to maintain uniformity with the RP2 lasers. A compact "Module-laser" was also developed, but its optical power spectral density limited its use in current ISS systems. Additionally, most engineering time in RP3 focused on developing the silica-ZBLAN splice recipe, crucial for the ISS laser's reliability and longevity.
The 3rd MPC version improved on its predecessors but still had issues, particularly with the transmitted laser beam stability necessary for system calibration. Unforeseen outcomes required live testing through three additional design iterations until the project's performance goals were met. To ensure beam stability in a vacuum, the internal volume was doubled, which allowed for screws instead of glue to secure the mirrors. This design change simplified production and reduced labor time, also benefiting end users by making mirror maintenance, such as cleaning, easier.
The ISS2 monitor was completed and tested. The laser's temperature control box malfunctioned, causing instability due to thermal effects. This was resolved by adding tubing for additional isolation and adjusting the laser box's TEC to keep the inner fan running, reducing thermal inertia. The LabView software (ISSPro) was partially rewritten to replace dysfunctional code and improve error handling. Long-term system tests were conducted to identify and fix remaining bugs, with an enhanced fitting algorithm introduced to handle nonlinear baselines. An email service was set up to send daily measurements in Excel format.
After initial testing and bug fixing, ISS2 was moved to WUR in Randwijk for validation, with ongoing support provided. ISS3 was assembled, and the assembly documentation was improved. Additional operational and software manuals were written. Finally, after a service check-up, ISS1 was successfully installed at a storage facility in Belgium.
