2010-11 Photos - Fixing the South Pole Telescope

all fixed
Above...the South Pole Telescope (SPT) and the rest of the Dark Sector
Laboratory (DSL) in December 2010, just after the gear replacement
had been completed (Peter Rejcek, Antarctic Photo Library)

The telescope was completed during the 2006-07 season, and has been busy searching the heavens ever since...looking for signs of how the universe got started. But...it is a big mechanical device...approximately 250 tons of heavy stuff sitting on an azimuth gear and driven by motors which seem to spin it back and forth incessantly. The azimuth gear like most others on cranes and radar antennas and such, has bearings and a lubrication system...and strainers and magnets to detect metal particles and contaminants in the lubricant. Well, as it turns out, about 2 years after commissioning, metal particles started to show up...which means that the bearings aren't holding up. The short term solution...keep the bearing packed with grease...until the long term solution, replacement of the azimuth (or "bull") gear could be done.

All this was arranged for the 2010-11 season...with assistance from Mammoet, a heavy lifting and rigging contractor...(this project was of special interest to me for more than one reason...I was involved with a similar project at the USAF radar site in Thule in 1978, replacing the bull gear on the 110-ton tracking radar antenna...and more recently I've worked with Mammoet on several of my refinery and power plant projects).

Basically, the project consisted of jacking up the antenna, unbolting and sliding out the old gear, sliding in the new one, and reinstalling the drive motors/gearboxes and hooking everything back up. Here's how it went down...

ramping things up
First...building a snow ramp to get the structural steel and other equipment up into the control room.
heavy stuff
Here's some of the equipment being staged.
measure twice cut once
Measuring to make sure everything will fit.
plugs for Antarctic science
And mapping out all of the cables so they can be properly reconnected.
jack me up

Some of the columns which will support the jacks.
slip and slide

Erecting the support structure for sliding out the old gear and sliding in the new one.
heavy stuff coming

Another view of the support structure erection.
steel yourself
Putting the support structure together.
getting on the beam
Rigging beams were installed from the telescope to handle the heavy stuff. Yes...some serious structural welding was involved.

Setting the jack support columns.
this is a frame up
Here's the assembled jacking support frame and jacks, before things start...
the men in the red suits
This panoramic view of the azimuth gear assembly shows the telescope partially jacked up.
getting jacked up about the Pole

A closeup of one of the jacking points after the jacking has been completed.
uplifting science
Like so. The old gear is still attached to the bottom of the raised telescope, and the rails are in place.
defeat is not an option
The sliding frame is in place, and the gear is being unbolted from above. At left is Erik Nichols, project manager from the University of Chicago.
tie one on
The old gear has been unbolted and lowered onto the sliding rails...
keeping things on track
...sliding the gear out from under the telescope...
gearing down

...so it can be lowered to the surface.
gearing up
Here goes the new azimuth gear.
pull for science

Looking from the other side...with a view inside the base (MM).
Let's do the twist
A closer view looking down inside the base...showing some of the wiring connections that allow the telescope to rotate 360 (MM).
bolt up
And the last stage of lifting the gear into place...lining up the bolts.
not quite done yet
Here's a shot of most of the crew...behind them, the new gear has been bolted into place.
looking at the deteriorated balls
Meanwhile, the old gear was taken to the heavy shop for disassembly and examination. What was determined? One of the bearings had been installed backwards by the manufacturer. With the replacement gear installed, the SPT has performed well, and more quietly (MM).

The hardest part was yet to come...lowering the telescope back into place, finishing the reassembly, and making sure that everything lined up properly in its original position. Then...lots of testing.

Additional coverage is available in this Antarctic Sun article. Several of these photos are from Marie McLane. Unless otherwise indicated, the rest of the photos are © Chris Kendall, and used by special permission. Chris is seated at the far right in the group photo above...thanks!

Next...the AST/RO demo and DNF siding...

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