Thursday, October 23, 2008

Day 6: Launch and Mission Summary


Sorry this post comes a day late, but the mission sequence necessitated us to stay silent for a while to avoid speculative misinformation and to be sure we know exactly what results we could draw from the mission. Indeed, we are still learning about the flight and probably will be for quite some time into the future. After a much accelerated count-down, Rexus 4 did finally launch and I have attached the video below. I apologize for the marginal quality, as I took this on my small photo-camera. We have slightly better launch videos, but for now this was the most suited to put on the web.


Now, to the mission itself. We still don't know the extend of success of the mission, pending further evaluation of our data. There was, however, a compromising event which affected the mission to some extend. After what began as a picture-perfect launch, MIRIAM began to transmit breathtaking views from space. All cameras worked flawlessly and recorded separation of the service module. However, a short time after MIRIAM separation, the payload section (containing our Camera Module on top and other experiments below) underneath the service module separated from the second stage booster as planned, but then collided with the Service Module. The impact happened approximately 15 seconds after the balloon was ejected and during the inflation sequence. A partially inflated balloon can be see just before impact, validating at least part of the experiment. The collision induced some tumbling and the fate of the balloon and instrument pod are yet uncertain, pending further evaluation of the video material, telemetry data and possibly recovery of either service module or instrument pod (the camera module is already recovered with the rest of the payload section). The service module continued to perform the inflation sequence nominally and continued to relay data until re-entering the atmosphere, offering stunning views of northern Scandinavia.

After hours of watching the tapes, this is the best account we can give so far. What seemed at first like a shocking deja-vu of the previous REGINA mission, turned out to be most likely caused by a distinct issue. As was quickly determined, both our timers and the rocket's timers behaved normally and issued separation signals on time. In contrast to Regina, the added first stage and much higher trajectory should have given us adequate time to distance ourselves from the payload section and booster. This, however, was not the case due to the service module becoming stuck on one of three of servomotors forming the locking mechanism. These servos were tested extensively on the shaker table, but the exact failure mode still needs to be determined. Although all servos opened at least partially, causing the separation signal to appear, MIRIAM did not become lose for another approximately 21 seconds. Even then, it no longer had an appreciable separation impulse, as the separation springs had already triggered. This caused it to drift slowly and delayed from the payload section below, resulting in inadequate separation distance and allowing the following payload section to catch up and collide.

Nevertheless, much useful data could be obtained, and the fate of the balloon is yet to be determined. Despite an unforeseen mechanical failure of the servo, many processes and systems performed beautifully, validating many aspects of our experiment.

Please note that this account is preliminary and unofficial, and as such can only be confirmed by the official press release.

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