Go UP young man!
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Today we started tether testing. Because of the low thrust we tested with the legs off. We also attached bungee cords to the tethers, not just to gather the slack but also to take up some of the weight of the vehicle. So this was a somewhat easier test with the bungee cords supplying some restoring torque. But, we'll take baby steps and work our way up.
This test also used the very last of the Lunar Lander Challenge peroxide. It was originally 80%, but has been sitting around for a few years so it was probably even less which was part of the reason for lack of thrust. We will be getting some new 90% peroxide from XL Space Systems for further testing. With 90% we can make enough thrust to lift off with the legs attached and no help from bungee cords.
For this test, the computer is doing attitude control only, and I am manually working the throttle. We don't have a height measurement sensor to close the loop on the throttle, and I'm not worrying about position control yet. The controller seemed to work okay. It stayed straight on most of the hops. It started to oscillate a little on the longest hop. We'll have to adjust the gains.
Video of tether test