Hello all, As some of you know, I'm involved with computing orbits for higher-flying (multi-day) artificial satellites. The higher artsats move at about the same speed as the closer asteroids, which tends to annoy the asteroid surveys. They will find an artsat, briefly think they've found a really interesting rock about to come near the earth or hit it, only to find out it's just a piece of junk. They find this disappointing, but there's enough leftover junk in high orbits that it happens every now and then. I've computed orbits for these as they are found, both so that they can be easily identified the next time the surveys stumble across them, and because there's some hope of one of them hitting the earth or moon. (So far, we've had one hit the earth -- WT1190F, last November, near Sri Lanka -- and a few close passes by both earth and moon.) See http://www.projectpluto.com/pluto/mpecs/pseudo.htm for some examples. Anyway. The SONEAR survey in Brazil picked up an object last night, to which they have given the designation S510923. It's in a nearly circular orbit around us, with a period of about five days. (Still some fuzziness in this, which further observations will, I hope, cure.) It's likely that this is related to the 1976 SOLRAD 11 mission. This put two probes (SOLRAD 11A, a.k.a. 1976-023C, and SOLRAD 11B, a.k.a. 1976-023D) and an apogee kick motor (1976-023H) into this sort of orbit. The folks at the Catalina Sky Survey in Arizona have found SOLRAD 11A, so it's nicely accounted for and we know S510923 isn't it : http://www.projectpluto.com/pluto/mpecs/76023c.htm SOLRAD 11B kept going until 1979. We do have a TLE for it from 1977, and the match to S510923 is quite encouraging. But if anyone has historical data from 1979 and can provide a TLE for SOLRAD 11B with a more recent epoch, it might really help figure out what's going on here. Observations and an orbit for S510923, in the Minor Planet Center's formats, are at http://www.projectpluto.com/pluto/mpecs/s510923.htm Thanks! -- Bill _______________________________________________ Seesat-l mailing list http://mailman.satobs.org/mailman/listinfo/seesat-lReceived on Mon Sep 05 2016 - 18:31:08 UTC
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