Preparing the second -80°C Freezer Flight Unit for the JEM in ISS 2004-01-2521
The first Flight Unit of the Minus Eighty degrees Celsius Laboratory Freezer for ISS (MELFI) has been delivered to NASA as Laboratory Support Equipment (LSE) by ESA, and is presently waiting for the next available Space Shuttle flight to be installed in the International Space Station.
The second Flight Unit is under preparation to be delivered at NASA-KSC in 2004 for JAXA, the Japanese Space Agency. Compared to the first unit, the acceptance of this second unit imposes the verification of requirements specific to the JEM, the Japanese Module in ISS.
The specificities of the JEM module, compared to the USLAB were analysed and adaptations were found to keep all MELFI Units compatible of both ISS modules.
The most important difference between JEM and USLAB is the water-cooling system, which has a much larger flow and inlet temperature ranges in JEM. MELFI design being tuned with very reduced margins for the USLAB conditions, the following questions had to be answered:
Is MELFI capable of keeping the nominal mission inside any of the two ISS modules?
What are the safety impacts on this enlarged thermal environment?
Are some operational constrains required to operate MELFI inside JEM?
Some improvement on the thermal control was first necessary to extend the working domain of the MELFI.
In parallel, thermal analyses allowed predicting the nominal behavior and assessing the safety impacts due to the enlarged conditions.
Finally, an extended test campaign has to confirm the compatibility with both JEM and USLAB of an upgraded MELFI design.
This paper presents the successive stages leading to final verification of a MELFI for JEM.