No. 1 - SPC Report February 2003
Probe Relay Sequence development (NASA/JPL activity)
The development of the Orbiter on-board software for the Probe Relay Sequence is finished. The software will be loaded into the Orbiter computers in early 2003 as part of the final planned Orbiter software update prior to arrival at Saturn. The revised Orbiter software, including the Probe Relay Sequence software, will be tested in-flight during a two-month period in March-April 2003. Revised Huygens mission implementation: status report The work related to the implementation of the Huygens recovery mission is progressing nominally. All details about the new trajectory for the Probe mission were agreed between ESA and NASA/JPL in December 2002. We are continuing to study in detail two mission options (no Probe pre-heating or 4-hour Probe pre-heating).
The data return in the no-preheating option (which is the current baseline) is more prone to link parameter uncertainties. The probe on-board software modifications that would be needed if the pre-heating option were to be selected have been developed. Testing and validation is planned in February-March at ESOC. The work is on schedule for a decision on which option to choose in early April 2003.
A review at Agency level of the revised Huygens mission is planned for September/October 2003.
Probe in-flight checkout
The 10th regular Probe in-flight checkout was successfully executed on 16 September 2002. The checkout review, held on 3 December 2002, confirmed the excellent health of all Probe subsystems in checkout configuration and the payload.
Probe Relay Test #5
The 5th Probe Relay Test was conducted on 25-27 November 2002. Its main objective was to quantify the expected data return and its robustness to link performance uncertainties in the no-preheating option. The DSN antenna in Madrid, which was used to transmit simulated Probe signals to the Huygens radio receivers, did not perform as well as the Goldstone antenna used for all previous tests. The test data are now under analysis but the impact of the under performance of the DSN antenna on the results of the test is still unknown.