Thursday, May 3, 2012

Gettin' BUSY At Work

Well, we're all cranked up for the next launch, around the end of May if things stay on-schedule. Spent the last two days debugging the telemetry tracking antenna I normally run, and learning more about it, and it's history, than I knew before.
We found today that the bearing assembly on the spinning feed is "almost shot" (it's got a lot of play in it), and although we can physically move each axis through its range of motion very smoothly (the mechanical stuff seems OK), when we turn on the servos and use the manually position hand wheels, the elevation axis doesn't respond smoothly. It kind of 'bumps and jumps' in response to commands from the Antenna Control Unit.
We're not sure if this is in the servo electronics somewhere, or in the software settings, but it's not right, and either contributed to, or is the cause of, the loss of track we had last mission.
I was on top of it as soon as it broke track, and put it in manual mode so I could get it back on the profile. Since this happened at first stage separation, AND we were running a "strange" flight profile, we didn't give it too much thought until the post mission review of the equipment logs showed some weirdness.
We break auto-track about 25% of the time at one-two staging due to the fact that the retros they use to back the first stage away from the second are solid fuel, and puff out a huge cloud of ionized gas around the launch vehicle, and RF doesn't go through ionized gas very well. It's why there's a communication blackout during reentry. Normally the tracking antenna will "coast" through this loss of signal, and reacquire on it's own, but the last time I had to coax it back to doing it's job, and it just didn't "feel" right.
We have a back up antenna array, but this thing is the darling of the RF Group, warts and all.
Oh, well, we'll either get it fixed, or write a "Use AS-IS" on it, and I'll just have to be really sharp during the launch.

This weekend, the YF and I are going to the Chino Airshow, so I'll post a bunch of pictures like I did last year.
Always an enjoyable event!

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