Four thousand, nine hundred, forty-four pounds. That's how much the ANITA-3 payload weighs. As a part of the hang test, CSBF weighs the payload by hanging them from a crane with a scale between the payload and the crane hook. We came just a few hundred pounds shy of the our estimate (5200 lbs) and of the maximum that the balloon can support (5500 lbs).
We had to pass several other tests as well to qualify as "flight ready." We spent the day with ANITA sitting outside first hanging from the BOSS, and then later sitting on the dance floor on the launchpad. During that time, the NASA staff at CSBF verified that they could communicate with their instruments on board our paylaod. The CSBF instruments allow us to talk to our instruments as a sort of gateway.
Through the NASA gateway, we can send up to a [byte])(http://en.wikipedia.org/wiki/Byte) (8 bits, 256 integer values) of data up to our payload at a time to change things. We have software on our computer that interprets these commands. We can do things like read log files, reboot the computer, turn parts of our instrument on and off. It's certainly less control than we have on the ground. So we had to think carefully about what commands to allow, and to test out as many of the commands as possible during the hang test. When both CSBF and the ANITA team were satisfied that everything worked, we became ready for launch!
Two systems on ANITA will deploy after launch: solar panels and a large, low-frequency antenna. We did this so that we could fit as many antennas on the experiment as possible, which improves our ability to detect any given neutrino and to determine where it interacted in the ice. During the launch, the solar panels sit in front of the bottom row of antennas, obscuring them. The low frequency antenna (my baby, by the way) is folded up like a paper lantern inside the bottom ring of the antennas. When commanded through telemetry, a pin holding up several guy lines on the solar panels will release, dropping the panels down just below the lower antennas. Another command releases the ropes cradling the large antenna like a basket. It drops down 6ft below the bottom antenna ring and expands another ten feet. On the ground ANITA is about 20 ft tall; fully deployed about 50 ft tall. We also had to demonstrate that our acutators holding up all those ropes would actually work as they are currently set up to be flight ready.
We're all ready to go with nowhere to be at the moment. Bad weather should be rolling in today, and we have to wait for a vortex to set up around the pole that will keep us hovering around Antarctica. The current estimate is ten days from now, so cross your fingers.