karn@eagle.UUCP (07/13/83)
As I mentioned yesterday, we finally did our first motor burn. Several hours afterwards, it became apparent that the burn had not gone according to plan; loss-of-signal times were much later than expected, indicating a burn that was too long. This has been confirmed; the burn should have been 107 sec, while it was in fact at least 190 sec. Why this happened is still a mystery; telemetry shows the motor unit counting down from the larger number even though a smaller number was supposedly loaded. The flight unit had been extensively tested on the ground with no failures. In any case, ranging over the last day has converged nicely into the following set of elements: Satellite: oscar-10 Catalog number: 14129 Epoch time: 83192.94024815 Mon Jul 11 22:33:57 1983 UTC Element set: DC5 Inclination: 26.4198 deg RA of node: 250.6344 deg Eccentricity: 0.6055096 Arg of perigee: 185.6573 deg Mean anomaly: 183.9066 deg Mean motion: 2.05848339 rev/day Semi major axis: 26106.161 km Anom period: 699.544144 min Apogee: 35535.588 km Perigee: 3920.526 km This is the FIRST time we have generated our own orbital elements based totally on our own information and modelling; a lot of work went into this part of the project and it has finally paid off. As you can see from the elements, the perigee is much higher than had been planned (1500 km); however, we still have more than half of our "delta v" (kick motor capability) left, and we are now working on a burn to bring us as close as we can to our desired final orbit. Keep your fingers crossed. Phil