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No. 40 - First In-flight test of Near Sun Hibernation Mode

No. 40 - First In-flight test of Near Sun Hibernation Mode

Report for period 8 to 22 April 2005The main activity in the reporting period was the successful first in-flight test of the Near Sun Hibernation Mode (NSHM), during which the spacecraft spent five days in this special low activity mode, with attitude controlled via Star Tracker and thrusters only (gyroscopes and reaction wheels are inactive).

The NSHM test started on 11 April and ended on 15 April, with a transition back into the normal GSEP attitude control mode. During the five days of test daily monitoring of the spacecraft performance confirmed the attitude control worked as expected. This test validated the NSHM approach that will be applied in the next few weeks for a full scale commissioning of the mode.

On 19 April a pass was dedicated to a MIDAS health check, following the commanding problems that occurred during the Passive Checkout (see report #39). The result of the activity was the confirmation that MIDAS is fully functional. Taking advantage of this activity, new versions of the MIDAS switch ON and OFF OBCPs (On-Board Control Procedures), modified according to a request by the PI Team, were uploaded and verified.

No other payload operations were carried out, with the exception of SREM, which is active continuously for radiation monitoring.

A total of 10 New Norcia passes of a fixed duration of 7 hours commanding were taken at three passes per week. In one case, on 21 April, the pass duration was reduced to less than 3 hours to cover an unplanned support request by SMART-1.

NNO Pass

Date

DOY

Main Activity

406

10.04.05

100

Short monitoring pass – change SHM guidance

407

11.04.05

101

Enter NSHM

408

12.04.05

102

Widen NSHM control deadband

409

13.04.05

103

Monitoring pass - NSHM

410

14.04.05

104

Reaction Wheels dehibernation

411

15.04.05

105

Exit NSHM

412

16.04.05

106

Monitoring pass

415

19.04.05

109

MIDAS Health check

416

20.04.05

110

Monitoring pass – uplink new STR B alignment

417

21.04.05

111

Monitoring pass – modify NSHM fuel FDIR threshold

At the end of the last New Norcia pass in the reporting period (DOY 112) Rosetta was at 16.02 million km from the Earth. The one-way signal travel time was 53.4 seconds.
Last Update: 1 September 2019
25-Oct-2021 16:42 UT

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