I last left off with the unhappy news that we're pushing the launch. But I don't want you to think that's where the White Sands work ended...in truth we had much, much more to do that week! Here's what happened:
When we decided to delay the flight we also decided to go ahead with the next steps of integration and vibration, as a practice run. We'll have to redo these when we come back for the real deal, but doing them now gives us a chance to identify and fix problems early. Integration is the process of connecting our experiment (the payload) with the rest of the rocket (systems for data telemetry, pointing control, and recovery, among others). These parts were made by a rocket team from Wallops Island, Virginia. Not only did we physically connect everything and make sure it fits (remember, we had some troubles earlier when we tried this with the first piece...) but we also tried running the power, data, and communication through their systems just like it will be during the flight. We did several sequence tests, where we run through everything in order as if we are doing the launch...except of course we don't launch anything. :) Most of these tests were easy as our system is relatively simple to integrate, but we did have to work out a couple more problems in mating various skins and sections together.
The next step was vibration! As I told you before, a vibration test is done on a shake table that simulates the shaking the rocket will feel during launch. Passing this test is absolutely essential to the health of the mission because it means that nothing will break or come loose during the launch. Many things could go wrong in a vibe test: parts could break, connectors could detach, bolts can come out as if an invisible hand is unscrewing them! We've never vibrated the electronics side of our payload, so this test served an important purpose. (Imagine if we came back in August and THEN found that we couldn't pass a shake test!) Fortunately, the test was a success! All the detectors (well, the ones that were still working after the accident...) showed no damage in the vibe test and still worked just as well afterward. What's more, there was no change in the alignment of the optics, despite the shims and regluing. So I'm happy to say that once we rebuild the detector system, all major obstacles to launch will have been cleared! (Yes, there are always more things that can go wrong, but this takes care of all the obvious areas for concern.)
There was one final step for our work in White Sands, and that was to ship everything back to Berkeley. Things were a little melancholy last Tuesday as we packed everything back up and loaded up the Fedex truck. A day later, we unloaded the truck in Berkeley and FOXSI was officially back home! So what's next? Well, we have to start over by rebuilding the detector system, but we can use everything we learned along the way, so the process will be much quicker this time. We first need to get more detectors from our colleagues at ISAS in Japan; as soon as we get those I will begin gluing them onto new boards. After the boards are loaded and wirebonded, we will start the process of testing and calibrating them...and then...we will bring FOXSI back to the desert and we will fly it!!! Right now we're looking at an August launch date; I will keep this blog going in the meantime so you can keep tabs on the rebuilding. :)
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