DDMS ORBITER TURNAROUND BRIEFING DDMS ORBITER TURNAROUND BRIEFING.
Using Onboard Telemetry for MAVEN Orbit Determination...MAVEN Background •Mars orbiter studying...
Transcript of Using Onboard Telemetry for MAVEN Orbit Determination...MAVEN Background •Mars orbiter studying...
![Page 1: Using Onboard Telemetry for MAVEN Orbit Determination...MAVEN Background •Mars orbiter studying the upper atmosphere and exploring the climate history •Science Orbit: –4.5 hour](https://reader033.fdocuments.us/reader033/viewer/2022042709/5f4735e482e5d67b144029ca/html5/thumbnails/1.jpg)
AAS/AIAA Space Flight Mechanics Meeting, 14.Jan.2014 1
Using Onboard Telemetry for
MAVEN Orbit Determination
Drew Ryan Jones
Try Lam, Nick Trawny, Cliff LeeJet Propulsion Laboratory, California Institute of Technology
![Page 2: Using Onboard Telemetry for MAVEN Orbit Determination...MAVEN Background •Mars orbiter studying the upper atmosphere and exploring the climate history •Science Orbit: –4.5 hour](https://reader033.fdocuments.us/reader033/viewer/2022042709/5f4735e482e5d67b144029ca/html5/thumbnails/2.jpg)
2AAS/AIAA Space Flight Mechanics Meeting, Jan-14-2014
MAVEN Background
• Mars orbiter studying the upper atmosphere and
exploring the climate history
2
• Science Orbit:
– 4.5 hour period
– 75 degree inclination
– Range of periapsis latitudes
– Periapsis altitude ~140-170
km (<120 km Deep-Dips)
![Page 3: Using Onboard Telemetry for MAVEN Orbit Determination...MAVEN Background •Mars orbiter studying the upper atmosphere and exploring the climate history •Science Orbit: –4.5 hour](https://reader033.fdocuments.us/reader033/viewer/2022042709/5f4735e482e5d67b144029ca/html5/thumbnails/3.jpg)
3AAS/AIAA Space Flight Mechanics Meeting, Jan-14-2014
• MAVEN Navigation requirements:
– Target a density corridor (0.05-0.15 kg/km3)
– Predict periapsis passage to 20 seconds
• Navigation challenges:
– Limited Doppler tracking (only 1-in-5 orbits)
– Between aerobraking and prior Mars science orbits
– Frequently changing attitude (incl. drag passes)
– Momentum desaturations after every periapsis (+11 min)
![Page 4: Using Onboard Telemetry for MAVEN Orbit Determination...MAVEN Background •Mars orbiter studying the upper atmosphere and exploring the climate history •Science Orbit: –4.5 hour](https://reader033.fdocuments.us/reader033/viewer/2022042709/5f4735e482e5d67b144029ca/html5/thumbnails/4.jpg)
4AAS/AIAA Space Flight Mechanics Meeting, Jan-14-2014
Modeling
• Mars-GRAM 2005 (MG05) - baseline atmosphere,
only estimate scale factor
– Quality density reconstruction better prediction
– But Mars atmosphere does not play nice!
• Lat/Lon dependence, unexpected trends, ect
• Scale factor variance up to 100% (orbit-2-orbit)
• Estimated Parameters (baseline):
– Epoch state
– Solar radiation pressure scale factor
– MG05 scale factor as stochastic (batch update each orbit)
– Desats as impulsive burns
4
![Page 5: Using Onboard Telemetry for MAVEN Orbit Determination...MAVEN Background •Mars orbiter studying the upper atmosphere and exploring the climate history •Science Orbit: –4.5 hour](https://reader033.fdocuments.us/reader033/viewer/2022042709/5f4735e482e5d67b144029ca/html5/thumbnails/5.jpg)
5AAS/AIAA Space Flight Mechanics Meeting, Jan-14-2014
![Page 6: Using Onboard Telemetry for MAVEN Orbit Determination...MAVEN Background •Mars orbiter studying the upper atmosphere and exploring the climate history •Science Orbit: –4.5 hour](https://reader033.fdocuments.us/reader033/viewer/2022042709/5f4735e482e5d67b144029ca/html5/thumbnails/6.jpg)
6AAS/AIAA Space Flight Mechanics Meeting, Jan-14-2014
Motivation / Goals
• Supplement sparse radiometric data with telemetry
derived measurements
– Improve density reconstruct/predict performance
– Combine observables into single batch estimation
• Generally valuable capability
– Enable cheaper (less tracking) and autonomous missions
– Applications to non-grav estimation:
• Aerobraking
• Thruster and SRP calibrations
• Finite burn reconstruction
6
![Page 7: Using Onboard Telemetry for MAVEN Orbit Determination...MAVEN Background •Mars orbiter studying the upper atmosphere and exploring the climate history •Science Orbit: –4.5 hour](https://reader033.fdocuments.us/reader033/viewer/2022042709/5f4735e482e5d67b144029ca/html5/thumbnails/7.jpg)
7AAS/AIAA Space Flight Mechanics Meeting, Jan-14-2014
IMU Observable Formulation
• Accelerometer (IMU):
– IMU frame body frame via gyros (onboard)
• CFD model of tabulated drag/moment coefficients
– Interpolant is relative velocity direction on unit sphere
Typically just compute bias (and IMU clock offset) apriori, and don’t
estimate further
7
![Page 8: Using Onboard Telemetry for MAVEN Orbit Determination...MAVEN Background •Mars orbiter studying the upper atmosphere and exploring the climate history •Science Orbit: –4.5 hour](https://reader033.fdocuments.us/reader033/viewer/2022042709/5f4735e482e5d67b144029ca/html5/thumbnails/8.jpg)
8AAS/AIAA Space Flight Mechanics Meeting, Jan-14-2014
Results: MAVEN cruise (TCM-1)
8
• Largest maneuver
until MOI
• 6-second IMU
clock offset
observed
![Page 9: Using Onboard Telemetry for MAVEN Orbit Determination...MAVEN Background •Mars orbiter studying the upper atmosphere and exploring the climate history •Science Orbit: –4.5 hour](https://reader033.fdocuments.us/reader033/viewer/2022042709/5f4735e482e5d67b144029ca/html5/thumbnails/9.jpg)
9AAS/AIAA Space Flight Mechanics Meeting, Jan-14-2014
Results: MAVEN cruise (TCM-1)
9
Fitting offset IMU data with
Doppler data does not work
![Page 10: Using Onboard Telemetry for MAVEN Orbit Determination...MAVEN Background •Mars orbiter studying the upper atmosphere and exploring the climate history •Science Orbit: –4.5 hour](https://reader033.fdocuments.us/reader033/viewer/2022042709/5f4735e482e5d67b144029ca/html5/thumbnails/10.jpg)
10AAS/AIAA Space Flight Mechanics Meeting, Jan-14-2014
Results: MAVEN Science
• Single drag pass fit (F2 and IMU)
– Bias of around 5 μm/s2
– Peak IMU acceleration: 100 μm/s2
– Centroid shifted by ~30 seconds
IMU observed net ΔV:
8.6 mm/s
Scaled MG05 net ΔV:
10.8 mm/s
![Page 11: Using Onboard Telemetry for MAVEN Orbit Determination...MAVEN Background •Mars orbiter studying the upper atmosphere and exploring the climate history •Science Orbit: –4.5 hour](https://reader033.fdocuments.us/reader033/viewer/2022042709/5f4735e482e5d67b144029ca/html5/thumbnails/11.jpg)
11AAS/AIAA Space Flight Mechanics Meeting, Jan-14-2014
Typical MAVEN
reconstruction batch
![Page 12: Using Onboard Telemetry for MAVEN Orbit Determination...MAVEN Background •Mars orbiter studying the upper atmosphere and exploring the climate history •Science Orbit: –4.5 hour](https://reader033.fdocuments.us/reader033/viewer/2022042709/5f4735e482e5d67b144029ca/html5/thumbnails/12.jpg)
12AAS/AIAA Space Flight Mechanics Meeting, Jan-14-2014
Conclusions
• Demonstrated uses:
– Reconstructed density information for 4/5 orbits where
radiometric data is absent
– Atmospheric functional data (beyond net ΔV)
• Larger ΔV during first deep-dip will be a real test
• Absence of telemetry during desats unfortunate
– If available, would it help? Noise still prohibitive?
• Further work
– Reduce data noise in IMU measurements (smoothing)
– Use alternate atmosphere model (more parameters)
– Utilize/test torque observable
![Page 14: Using Onboard Telemetry for MAVEN Orbit Determination...MAVEN Background •Mars orbiter studying the upper atmosphere and exploring the climate history •Science Orbit: –4.5 hour](https://reader033.fdocuments.us/reader033/viewer/2022042709/5f4735e482e5d67b144029ca/html5/thumbnails/14.jpg)
14AAS/AIAA Space Flight Mechanics Meeting, Jan-14-2014
BACKUP
![Page 15: Using Onboard Telemetry for MAVEN Orbit Determination...MAVEN Background •Mars orbiter studying the upper atmosphere and exploring the climate history •Science Orbit: –4.5 hour](https://reader033.fdocuments.us/reader033/viewer/2022042709/5f4735e482e5d67b144029ca/html5/thumbnails/15.jpg)
15AAS/AIAA Space Flight Mechanics Meeting, Jan-14-2014
Torque Observable Formulation
• CFD model of tabulated drag/moment coefficients
– Interpolant is relative velocity direction on unit sphere
• Torque from reaction wheel speeds
15
![Page 16: Using Onboard Telemetry for MAVEN Orbit Determination...MAVEN Background •Mars orbiter studying the upper atmosphere and exploring the climate history •Science Orbit: –4.5 hour](https://reader033.fdocuments.us/reader033/viewer/2022042709/5f4735e482e5d67b144029ca/html5/thumbnails/16.jpg)
16AAS/AIAA Space Flight Mechanics Meeting, Jan-14-2014
Results: MAVEN science
• Drag pass in IMU observable (unsmoothed)
– Bias of around 5 μm/s2
– Peak IMU acceleration: 100 μm/s2
16
![Page 17: Using Onboard Telemetry for MAVEN Orbit Determination...MAVEN Background •Mars orbiter studying the upper atmosphere and exploring the climate history •Science Orbit: –4.5 hour](https://reader033.fdocuments.us/reader033/viewer/2022042709/5f4735e482e5d67b144029ca/html5/thumbnails/17.jpg)
17AAS/AIAA Space Flight Mechanics Meeting, Jan-14-2014
Results: MAVEN Science
• Single drag pass fit (F2 and IMU), unsmoothed
– Bias of around 5 μm/s2
– Peak IMU acceleration: 100 μm/s2
– Centroid shifted by ~45 seconds
IMU observed net ΔV:
9.1 mm/s
Scaled MG05 net ΔV:
10.8 mm/s
![Page 18: Using Onboard Telemetry for MAVEN Orbit Determination...MAVEN Background •Mars orbiter studying the upper atmosphere and exploring the climate history •Science Orbit: –4.5 hour](https://reader033.fdocuments.us/reader033/viewer/2022042709/5f4735e482e5d67b144029ca/html5/thumbnails/18.jpg)
18AAS/AIAA Space Flight Mechanics Meeting, Jan-14-2014
IMU accelerations, orbit 307
IMU accelerations, orbit 314
MAVEN reconstruction batch
• IMU data suggests less ΔV
• IMU centroid always later (but
as little as 5 sec)
IMU observed
net ΔV: 4.1
mm/s
Scaled MG05
net ΔV: 6.0
mm/s
IMU observed
net ΔV: 3.4
mm/s
Scaled MG05
net ΔV: 4.6
mm/s
![Page 19: Using Onboard Telemetry for MAVEN Orbit Determination...MAVEN Background •Mars orbiter studying the upper atmosphere and exploring the climate history •Science Orbit: –4.5 hour](https://reader033.fdocuments.us/reader033/viewer/2022042709/5f4735e482e5d67b144029ca/html5/thumbnails/19.jpg)
19AAS/AIAA Space Flight Mechanics Meeting, Jan-14-2014
MRO: Mars-GRAM Scale Variation