November 1990
1st Nov. : GRU, HED, KEP & SIM monitored and controlled.
2nd Nov. : KEP switched off.
TCM 2 performed nominally.
3rd Nov. : SIM switched off.
LAN cover release performed. LAN temperature changes indicate
successful releases.
STO switched on and intitial checkout completed successfully.
X-band switched on to monitor boom deployment.
Wire Booms deployed successfully.
X-band switched off.
4th Nov. : Axial Boom Deployed.
KEP & SIM switched on.
HED switched off and back on for STO to monitor noise levels.
Unexpected nutation build up over several hours after boom
deployment. Maximum of about 0.5 deg cone angle. Spacecraft
switched to 1024 bps Eng. at 0230 GMT (doy 309) to monitor
overnight.
5th Nov. : Spacecraft switched back to 1024 bps Sci. at 1845 GMT.
6th Nov. : GLG switch on successfully.
GRU channeltron switched on.
STO checkout continued.
Switched to 1024 bps Eng. at 0145 GMT (doy 311).
Further analysis of the nutation.
Switched to 1024 bps Sci. at 0310 GMT.
7th Nov. : GLG DPPS switched to mode 1. MCP switched on.
STO Sounder test performed.
Switched to 1024 bps Eng. at 0040 GMT (doy 312).
1 pulse manoeuvre performed successfully.
Switched to 1024 bps Sci. at 0340 GMT.
8th Nov. : GLG MCP switched to level 2, PAPS switched on to 8 kV.
STO checkout continued.
Switched to 1024 bps Eng. at 2230 GMT.
Two 1 pulse spacecraft dynamics assessment manoeuvres
performed. Nutation damped briefly, but spacecraft seems
stable at about 0.35 degrees maximum half-cone angle.
Switched to 1024 bps Sci. at 0215 GMT (doy 313).
9th Nov. : HUS switched on successfully after some problems with wrong
spacecraft data handling configuration. Redundant experiment
interface had been configured so no data was being read into
telemetry. HUS HV on.
GLG PAPS switched to 11.5 kV.
10th Nov. : HUS checkout continued. Burst mode tested.
STO FES checkout continued.
KEP GAS sequences continued.
GLG MCP switched to level 3, PAPS to 14.0 kV.
11th Nov. : Weekend monitoring.
12th Nov. Weekend monitoring.
13th Nov. : LAN switch-on delayed.
Switched to 1024 bps Eng. at 1740 GMT.
X-band on. S-band telemetry.
Nutation angle found to be about 2 deg. half cone angle from
ground AGC levels and further study of the sun sensor data.
2 Slew manoeuvres performed successfully.
Spin rate changed to 4.9 rpm but nutation increased
significantly. Spin correction to 4.99 rpm decreased
nutation again. Spacecraft monitored overnight in Eng.
14th Nov. : Switched to 1024 bps Sci. at 1720 GMT.
LAN switched on successfully.
GLG PAPS switched to 15.4 kV.
X-band switched off for thermal reasons.
15th Nov. : LAN checkout.
Switched to 1024 bps Eng. at 0100 GMT (doy 320).
Performed spin up to 5.1 rpm in 2 steps. Nutation decreased
from 4.38 to 3.1 deg full cone in 4 hours.
Switched to 1024 bps Sci. at 0630 GMT (doy 320).
16th Nov. : BAM-E switched on.
BAM-I switched on.
GLG PAPS to 17.9 kV.
17th Nov. : Performed spin up to 5.1 rpm.
BAM-E & BAM-I checkout.
18th Nov. : Weekend monitoring.
19th Nov. Weekend monitoring.
20th Nov. : Monitor and control of experiments.
Earth pointing manoeuvre.
Nutation levels of 2.4 to 3.5 degrees since spin-up. Cyclic
variation with a period of about 22 hours. Very slight
overall downward trend.
21st Nov. : Monitor and control of experiments.
Thermal reconfiguration.
22nd Nov. : Monitor and control of experiments.
23rd Nov. : Monitor and control of experiments.
24th Nov. : Weekend monitoring.
25th Nov. Weekend monitoring.
26th Nov. : Monitor and control of experiments.
Earth pointing manoeuvre.
Spin-up manoeuvre not performed because of concerns that the
axial boom may go into resonance. Discussion is ongoing as to
the best course of action.
NOTE : SPIN RATE IS STILL 5.2 RPM.
The theory is that energy is supplied to the spacecraft from
the solar radiation pressure acting on the non-symetric axial
boom. If this is true, then the energy input will reduce as
the solar aspect angle decreases, particularly when the boom
is shadowed by the body of the spacecraft (SAA less than 7
degrees).
It is also suggested that the nutation level as calculated
from the sun sensor data should include a further factor
which increases as the solar aspect angle decreases. This
factor, currently calculated to be 2.5, implies that the
half-cone nutation angle is at present between 2.75 and 3.0
degrees and reducing only very slowly.
27th Nov. : Monitor and control of experiments.
28th Nov. : Monitor and control of experiments.
Data gap from approx. 09:45 - 13:25 GMT. Part of DSS 12 pass
given to Galileo so that they can perform vital operations
before Earth flyby.
29th Nov. : Monitor and control of experiments.
Tape recorder operations :
333:07:12:11 512 bps Sci.
333:07:20:43 Record
333:13:08:59 2048 bps interleaved 1:1 (1024 bps real-time tm)
333:13:21:47 Playback
333:16:30:03 1024 bps Sci.
Please check your data for this period since this is the first
processed playback data.
Axial boom motor powered for 30 minutes starting 333:22:30.
Nutation level decreased from 4.3 to 3.4 deg full-cone over
the next few hours, then increased again to around 3.9 deg.
After 24 hours, it seems that the level is not returning to
4.3 deg.
30th Nov. : Monitor and control of experiments.
GLG PAPS to 20..3 kV
Earth pointing manoeuvre.