No. 42 - Spacecraft Thermal Characterisation Activities
On 18 May a test was executed to verify that the High Gain Antenna motor can be operated for indefinite periods without the overheating problems occurring at shorter Sun distances. The test confirmed that the motor can be operated at least for the duration of a full ground station pass.
A thermal characterisation test was executed on 23 May, to verify that the spacecraft can be pointed with its -Z side to the Sun without overheating the thruster modules. This test also confirmed that no dangerous temperatures are achieved, however thermal stability was not reached within the planned 12 hours.
The Thermal Control Table (TCT) was reconfigured on 24 May to its intermediate state, at a distance of 1.2 AU from the Sun.
No payload operations were carried out, with the exception of SREM, which is active continuously for radiation monitoring.
A total of 6 New Norcia passes each with a duration of about 8 hours commanding were taken over the reporting period (three passes per week).
|
NNO Pass |
Date |
DOY |
Main Activity |
|
443 |
17.05.05 | 137 | Monitoring pass - go/no-go thermal APM test |
|
444 |
18.05.05 | 138 | Antenna Point Mechanism (APM) thermal test + change configuration of NM guidance |
|
445 |
19.05.05 | 139 | Monitoring pass - swap to Star Tracker A |
|
449 |
23.05.05 | 143 | Thermal characterisation: Sun -50° |
|
450 |
24.05.05 | 144 | Change TCT to intermediate in RAM |
|
451 |
25.05.05 | 145 | Monitoring pass |
At the end of the last New Norcia pass in the reporting period (DOY 147) Rosetta was at a distance of 34.7 million kilometres from Earth. The one-way signal travel time was 1 minute and 55.7 seconds.