Active monitoring of the drive units on the Gemini South dome are ongoing in order to avoid the failures which recently occurred at Gemini North. These include an exhaustive review of bearing lubrication procedures, as well as a re-evaluation of the loads acting on the bearings. Bearings are now well lubricated and the loads acting on them are confirmed to be within manufacturer specifications. In this photo, Pablo Díaz, Mechanical Engineer, inspects the drive unit at Gemini South.
Seven days after removing the Drive Box, the Drive Box assembly has been repaired, refurbished, and reassembled. Both Gearboxes within the Drive Box have been extensively tested in preparation for the re-installation of the Drive Box back into the shutter. Gemini North is still on schedule to return to normal operations by the end of next week.
In the meantime, watch this video illustrating the difficulties of accessing the Drive Box unit on the Gemini dome!
Gemini staff are making good progress on preparations to physically lock both the top and bottom shutters in place, which must be done before the left (from the outside looking in) shutter Drivebox can be removed. This is being done by the addition of a total of four shear angle plates with structural bolts, connected to the enclosure structure, that exceed the loading requirements.
The team also reports that they are on track to safely remove the Drivebox next week.
A mechanical failure of a key drive unit high on the outer side of the Gemini North dome will force a shutdown of operations until the unit is repaired. It is expected that the repair will take on the order of a month to complete due to the difficulty of accessing the drive unit.
The mechanism, which works in tandem with an identical unit on the opposite side of the Gemini observing slit, appears to have suffered the same fate as the unit’s companion that failed in late 2013. Gemini’s Director, Markus Kissler-Patig expects that the repair will proceed more quickly since we now understand how to make these repairs. “Because these drive units are used at both telescopes we urgently need to understand the cause of the failure in order to avoid this happening again in the future. Fully understanding the problem is our highest engineering priority.”
Gemini is currently informing all PIs of active Gemini North programs. The repair will not impact the planned visiting instruments DSSI and TEXES scheduled for July and August of this year. In addition, we are investigating options to minimize impact on the overall scientific productivity by moving work forward from the maintenance shutdown scheduled for September 2014.
Watch this blog for regular updates on this repair work.