Istituto Nazionale Di Astrofisica - Istituto di Fisica dello Spazio Interplanetario ISA TeamISA Progress MeetingRome, 26 May 2009 ISA operations in cruise.
Post on 27-Mar-2015
212 Views
Preview:
Transcript
Istituto Nazionale Di Astrofisica - Istituto di Fisica dello Spazio Interplanetario
ISA Team ISA Progress Meeting Rome, 26 May 2009
ISA operations in cruise
• RSE support• In-cruise calibration• Periodical checkouts• Long-term stability tests• ISA “cruise science”
• RSE support• In-cruise calibration• Periodical checkouts• Long-term stability tests• ISA “cruise science”
Istituto Nazionale Di Astrofisica - Istituto di Fisica dello Spazio Interplanetario
ISA Team ISA Progress Meeting Rome, 26 May 2009
ISA operations in cruise
Superior Conjunction Experiment (SCE)
•Quiet dynamical environment (no thrust)•High-precision tracking•ISA on
ISA support of PODISA support of POD
5000 5500 6000 6500 7000 75000.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
1.2BepiColombo MCS Cruise - 2013 trajectory
t [MJD2000]
Dis
tanc
e fr
om t
he S
un [
AU
]
Distance from the Sun
Istituto Nazionale Di Astrofisica - Istituto di Fisica dello Spazio Interplanetario
ISA Team ISA Progress Meeting Rome, 26 May 2009
ISA operations in cruise
The direct solar radiation pressure signal is above ISA sensitivity (possibly inside ISA band if MCS is rotating)
5000 5500 6000 6500 7000 75000
0.2
0.4
0.6
0.8
1
1.2
1.4x 10
-7 BepiColombo MCS Cruise - 2013 trajectory
t [MJD2000]
Acc
eler
atio
n [m
s-2
]
Direct solar radiation pressure
Possibility of instrument calibration by comparison with tracking
Istituto Nazionale Di Astrofisica - Istituto di Fisica dello Spazio Interplanetario
ISA Team ISA Progress Meeting Rome, 26 May 2009
ISA operations in cruiseRequired information for in-cruise calibration
• Estimation of tracking accuracy during SCEtracking accuracy during SCE, and therefore of the accuracy in recovering the MCS acceleration
• Estimation of the expected acceleration signal acting on the expected acceleration signal acting on the MCSMCS, to be confronted with the tracking accuracy and accelerometer sensitivity
• Re-assessment of expected signals acting on the sensing expected signals acting on the sensing elementselements, taking into account the different positioning of ISA with respect to MCS COM (instead of MPO COM)
• Estimation of tracking accuracy during SCEtracking accuracy during SCE, and therefore of the accuracy in recovering the MCS acceleration
• Estimation of the expected acceleration signal acting on the expected acceleration signal acting on the MCSMCS, to be confronted with the tracking accuracy and accelerometer sensitivity
• Re-assessment of expected signals acting on the sensing expected signals acting on the sensing elementselements, taking into account the different positioning of ISA with respect to MCS COM (instead of MPO COM)
Transducer factor
Istituto Nazionale Di Astrofisica - Istituto di Fisica dello Spazio Interplanetario
ISA Team ISA Progress Meeting Rome, 26 May 2009
ISA operations in cruise
Periodical checkouts
Long-term stability tests
• Zero position of the sensing massesZero position of the sensing masses: potential drifts in the working positions of the sensing masses will be detectable by a continuous read-out
• Noise levelNoise level: the (nearly constant) solar radiation pressure and the residual vibrations on MCS being the only source of vibration noise, it will be possible to test the instrument intrinsic noise with high accuracy
Istituto Nazionale Di Astrofisica - Istituto di Fisica dello Spazio Interplanetario
ISA Team ISA Progress Meeting Rome, 26 May 2009
ISA operations in cruise
“Cruise science”
• Direct measurement of solar radiation pressure• Flybys (“anomalies”, gradiometric measurements)• Direct measurement of solar radiation pressure• Flybys (“anomalies”, gradiometric measurements)
An accelerometer disentangles gravitational and non-gravitational effects
Out of the spacecraft center of mass, an accelerometer measures also gravity gradients
Istituto Nazionale Di Astrofisica - Istituto di Fisica dello Spazio Interplanetario
ISA Team ISA Progress Meeting Rome, 26 May 2009
ISA operations in cruise
RSE-RD 50 ASD TN 35 page 11
ISA operation requirements for SCE
top related