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Ulysses Status Report - April 2003

Ulysses Status Report - April 2003

The mission is progressing nominally, with spacecraft and all scientific instruments in goodhealth. Unusually, three Anomaly Reports (ULY056, 57, and 58) were issued during thereporting period. The first concerned a command error caused by an incorrect bit-rateselection, while the second anomaly was the result of ground segment problems. The subjectof Anomaly Report ULY058 ('EPC Switchover 2') is an autonomous switch-over from theprime to the redundant Travelling Wave Tube Amplifier (TWTA) and Power Conditioningunits (EPC) that occurred on 15 February, and the subsequent failure to switch back to theprime units on 6 March. The redundant EPC/TWTA units are operating nominally, and nofurther attempts will be undertaken to switch back to the prime units at this time.

The investigation into the anomaly is still in progress. The possible extension of spacecraft  operations beyond September 2004 will be discussed by the Solar System Working Group at its meeting on 23 April. The Ulysses proposal to the NASA Sun-Earth Connections (SEC) Senior Review (to be held 10-13 June) will be submitted by the JPL Project to NASA HQ on 30 April. On 1 May, Ulysses will be at a radial distance of 4.84 AU from the Sun, and heliographic latitude 16: north of the solar equator, on its way to aphelion.

Science Highlights

For the first time since 1992, Jupiter is starting to figure strongly in the scientific activities of the Ulysses teams. On 5 February 2004, the spacecraft will encounter the giant planet for the second time. Unlike the 1992 fly-by, however, this will be a distant encounter (closest approach will be at 1684 Jovian radii from the planet's centre, compared with 6 Jovian radii in 1992). Another difference between the two fly-bys is that this time, the spacecraft will approach the planet from high northern latitudes. This difference is already apparent in the radio data from the URAP experiment on board Ulysses. In February and March 2003, URAP detected intense radio emission from Jupiter, at levels well above those seen in 1993 when Ulysses was at comparable distance from the planet (approx. 2.8 AU). This bodes well for the data to be acquired in November-December, when Ulysses will be much closer to the planet, and at 75: north of the planet's equator. Of particular interest are periodic auroral phenomena which produce both radio and X-ray bursts. The quasiperiodic X-rays, observed by the Chandra X-ray Observatory were observed primarily from the northern hemisphere.

Last Update: 1 September 2019
17-Oct-2021 06:08 UT

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