Monday, October 24, 2005
Sunday, October 23, 2005
Explorer 42
1970-107A
The first small Explorer payload, SAS-A, carried two x-ray proportional counters provided by the American Science and Engineering team which later became the x-ray astronomy group of the Smithsonian Astrophysical Observatory. It was launched at 1053 on 1970 Dec 12 by a Scout B from the San Marco Launch Complex in the Indian Ocean off Kenya. It reached a 95.30 min, 522 x 563 km x 3.04 deg orbit and began operations on Dec 18. SAS-A was given the designations Small Astronomy Satellite 1 (SAS 1) and Explorer 42, but it is famous by the name given to it in honor of the Kenya-based launch site - Uhuru, the Swahili for `freedom'. Uhuru was the first successful x-ray astronomy satellite and made a survey of the 2-10 keV x-ray sky which was turned into a series of catalogs, the final one being the Fourth Uhuru (4U) catalog. Uhuru operations ended on 1973 Mar 18 and the satellite reentered on 1979 Apr 5.
| Uhuru | |||
| Date | Time | Event | Orbit |
|---|---|---|---|
| 1970 Dec 12 | 1053:50 | Launch by Scout B S175C | SMLC |
| T+1:16 St 1 burnout | |||
| T+1:19 Stage 2 burn | |||
| T+1:59 Stage 2 burnout | |||
| T+2:13 Stage 3 burn | |||
| T+2:49 Stage 3 burnout | |||
| T+9:05 spinup | |||
| T+9:07 Stage 3 sep | |||
| 1103:02 | T+9:12 Stage 4 burn | ||
| 1103:37 | T+9:47 Stage 4 burnout | ||
| 1108:17 | T+14:27 Stage 4 sep | ||
| Magnetic despin | |||
| 1970 Dec 13 | 95.76 535 x 574 x 3.0 | ||
| 1971 Feb | Tape recorder failed | ||
| 1971 May 25 | 95.63 530 x 568 x 3.0 | ||
| 1971 Aug | Transmitter strength weakened | ||
| 1971 Sep | Degraded star sensors | ||
| 1971 Dec | Transmitter recovered | ||
| 1972 Mar | Battery failed, day ops only | ||
| 1973 Mar 18 | End of ops | ||