Giving Feedback and Resident Evaluation ارایه فیدبک و ارزیابی تخصص Gary Davis MD.
Gary Davis Robert Estes Scott Glubke
16
Final Version Gary Davis Robert Estes Scott Glubke Propulsion May 13-17, 2002 Micro Arcsecond X-ray Imaging Mission, Pathfinder (MAXIM-PF)
description
Micro Arcsecond X-ray Imaging Mission, Pathfinder (MAXIM-PF). Propulsion. Gary Davis Robert Estes Scott Glubke. May 13-17, 2002. Launch. Insertion. L2. Lunar Orbit. Mid Course Corrections. projection onto ecliptic plane (RSR frame). Functional Requirements & Assumptions (1 of 3). - PowerPoint PPT Presentation
Transcript of Gary Davis Robert Estes Scott Glubke
Final Version
Gary DavisRobert EstesScott Glubke
Propulsion
May 13-17, 2002
Micro Arcsecond X-ray Imaging Mission, Pathfinder (MAXIM-PF)
LAI MAXIM-PF May 13-17, 2002Goddard Space Flight Center
PropulsionPage 2
Final Version
Functional Requirements & Assumptions (1 of 3)
General Range Safety: EWR-127-1 and MIL-STD-1522A
(launch/processing @ KSC/CCAS) Class A mission: single fault tolerant Transfer stage needs only axial thrust, ACS thrust Optics Hub, Detector, and Free Flyers need thrust in all directions 1 year in Phase1 with 45 reors., 4 years in Phase2 with 45 reorientations. Thruster contamination and EM issues can be “engineered” Broad thrust ranges
Transfer to L2 All S/C are attached together High thrust chemical propulsion needed for:
ELV velocity dispersions Mid-course corrections during transfer trajectory Insertion maneuver near L2
Transfer stage is jettisoned Assume need to safe/vent this stage (inject into helio orbit)
projection onto ecliptic plane(RSR frame)
Mid Course Corrections
Lunar Orbit
Launch
Insertion
L2
LAI MAXIM-PF May 13-17, 2002Goddard Space Flight Center
PropulsionPage 3
Final Version
“Lissajous Stabilization” at L2 Thrust needed on all S/C to maintain the Lissajous orbit Assume that science observations are stopped for stabilization
maneuvers Formation Keeping
Optics Hub S/C is the leader and does not need to perform any formation keeping maneuvers
Detector S/C follows the leader and need to perform maneuvers to keep up
Free Flyer Optics S/C also need to perform formation keeping maneuvers
Reorientation Maneuvers Optics Hub is assumed to rotate in place (it’s the leader) Detector and free flyer S/C maneuver to match the Optics Hub’s
orientation 10 degree reorientation assumed Phase1 = 1 day, Phase2 = 7 days
Functional Requirements & Assumptions (2 of 3)
LAI MAXIM-PF May 13-17, 2002Goddard Space Flight Center
PropulsionPage 4
Final Version
Functional Requirements & Assumptions (3 of 3)
Lissajous Stabilization Thrust Control: For Lissajous stabilization, the S/C can be reoriented to align thrusters
with desired velocity direction Maneuvers will be short so power should not be a problem Plan maneuvers after observations, before the next reorientation to minimize
science downtime
Formation Keeping (& reor.) Thrust Control: Translational thrust needed in ALL directions 6 DOF (+/- X, Y, & Z) Maximum thrust needed is approx. 20 mN Minimum thrust needed is approx. 3X10-4 mN (this is < 1 microN) A five order of magnitude thrust range
Formation Keeping (& reor.) ACS Control: Torques needed about all axes 6 DOF (+/- Roll, Pitch, & Yaw) Minimum Impulse Bit = 20 microNs
LAI MAXIM-PF May 13-17, 2002Goddard Space Flight Center
PropulsionPage 5
Final Version
L2 Propulsion Insertion Module Carries All S/C attached together Axial del-V thrust, 3 axis ACS High thrust chemical system Functions:
Launch Vehicle Correction Contingency Mid-Course Correction (MCC) Lissajous Orbit Insertion (LOI)
Transfer to L2 Transfer from ELV trajectory to L2 orbit: 200 m/s
Assumes a Delta-IV Launch Vehicle C3 = -0.7 km^2/s^2
Transfer stage is jettisoned after LOI Needs to be safed (vented, helio orbit) to meet orbit debris
requirements
Transfer Stage Requirements
projection onto ecliptic plane(RSR frame)
Mid Course Corrections
Lunar Orbit
Launch
Insertion
L2
LAI MAXIM-PF May 13-17, 2002Goddard Space Flight Center
PropulsionPage 6
Final Version
Detector S/C is a follower at L2 Phase1 Maneuvers: Acceleration Delta-V
Lissajous Stabilization N/A 25 m/s per year in Phase1 Formation Keeping 1X10-6 m/s^2 0.0864 m/s / day
(tot=32) Reorientation 1.9X-5 m/s^2 1.61 m/s ,1 day reor.
(tot=117*) Phase2 Maneuvers:
Lissajous Stabilization N/A 100 m/s in Phase2 Formation Keeping 1.1X10-5 m/s^2 .95 m/s / day
(tot=1389) Reorientation 3.81X10-5 23.1 m/s , 7 day reor. (tot=2042*)
*Includes formation keeping during reorientations and 1.5x correction factor
Note: Phase1 = 1yr, 45 reorientations, Phase2 = 4yr, 45 reorientations
Detector S/C Requirements
LAI MAXIM-PF May 13-17, 2002Goddard Space Flight Center
PropulsionPage 7
Final Version
Optics Hub S/C is the leader at L2 Phase1 Maneuvers: Acceleration Delta-V
Lissajous Stabilization N/A 25 m/s in Phase1 Formation Keeping None needed (hub is the leader) Reorientation None needed (hub is the leader)
Phase2 Maneuvers: Lissajous Stabilization N/A 100 m/s in Phase2 Formation Keeping None needed (hub is the leader)
Reorientation None needed (hub is the leader)
Optics Hub S/C Requirements
LAI MAXIM-PF May 13-17, 2002Goddard Space Flight Center
PropulsionPage 8
Final Version
Free Flyer Optics S/C (all 6) are followers at L2 Phase1 Maneuvers: Acceleration Delta-V
Lissajous Stabilization N/A (not deployed from Optics Hub S/C) Formation Keeping N/A (not deployed from Optics Hub
S/C) Reorientation N/A (not deployed from Optics Hub S/C)
Phase2 Maneuvers: Lissajous Stabilization N/A 100 m/s in Phase2 Formation Keeping 1X10-6 m/s^2 0.0864 m/s
per day (tot=380*) Reorientation 1X10-9 m/s^2 6X10-4 m/s/7 day
reor. (tot=12*)
*Includes formation keeping during reorientations and 3x correction factor
Note: Phase1 = 1yr, 45 reorientations, Phase2 = 4yr, 45 reorientations
Free Flyer S/C (6) Requirements
LAI MAXIM-PF May 13-17, 2002Goddard Space Flight Center
PropulsionPage 9
Final Version
Transfer Stage Propulsion Design
Transfer Stage Monopropellant hydrazine using unregulated pressurization 500 kg total mass for the stage
410 kg of hydrazine 3 kg of pressurant 40 kg for a 42 in diameter titanium tank with AF-E-322 diaphragm 42 kg remains for thrusters/plumbing components/structure/sep
systems Reduce debris hazard after separation: venting/orbit change
Thrusters Needs a thrust for a 50 m/s burn to be performed in < 1 hour 25 N engines located (in pairs) in 4 locations (8 engines total)
Delta-V
LAI MAXIM-PF May 13-17, 2002Goddard Space Flight Center
PropulsionPage 10
Final Version
Optics Hub Architecture
Optics Hub: L2 Stabilization
8 hydrazine thrusters, single diaphragm tank, blowdown Simple high thrust design
12 MEMS cold gas ACS thrusters Mass: wet = 77 kg, dry=15 kg Power: 5 W (valve and heater power accounted by other
subsystems) Cost:$1000k
LAI MAXIM-PF May 13-17, 2002Goddard Space Flight Center
PropulsionPage 11
Final Version
Detector Architecture
Detector: L2 Stabilization
8 hydrazine thrusters, single diaphragm tank, blowdown Simple high thrust design 24 kg hydrazine
Formation keeping and reorientation 4 – 3nozzle Pulsed Plasma Thrusters (PPT’s = $250k each) 87 kg Teflon
Mass: wet = 153 kg, dry=42 kg Maneuver power : 300 W (valve and heater power accounted by
other subsystems) Cost:$2000k
LAI MAXIM-PF May 13-17, 2002Goddard Space Flight Center
PropulsionPage 12
Final Version
Free Flyer Architecture
Free Flyer L2 Stabilization
8 hydrazine thrusters, single diaphragm tank, blowdown Simple high thrust design 14 kg hydrazine
Formation keeping and reorientation 4 – 3nozzle Pulsed Plasma Thrusters (PPT’s = $250k each) 8 kg Teflon
Mass: wet = 64 kg, dry=42 kg Maneuver power: 10 W (valve and heater power accounted by
other subsystems) Cost: $2000k
LAI MAXIM-PF May 13-17, 2002Goddard Space Flight Center
PropulsionPage 13
Final Version
Detector, Free Flyer: PPT
LAI MAXIM-PF May 13-17, 2002Goddard Space Flight Center
PropulsionPage 14
Final Version
Detector, Free Flyer: Low Thrust Options, Typical
performance
TECHNOLOGY Isp min I-bitpower,
minpower, max mN
thruster wt., kg
system, kg
PPT (gen) 500-1400 1e-5-150e-5 5 150 .01-3 1.5 5
PPT teflon 200-1400 5.00E-05 5 70 .1-4.5 1.5 5gas PPT 5000 1.00E-05 5 150 .1-1 1.5 6.5
Cesium FEEP 9000 1.00E-08 3 370 .01-2.8 0.45 3
small ion1800-3500 no pulse 100 500 5-20 2.5-5
micro ion2000-3000 no pulse 10 50 .05-.5 <1
Colloid 500-1450 1.00E-08 2 10 .001-.3
LAI MAXIM-PF May 13-17, 2002Goddard Space Flight Center
PropulsionPage 15
Final Version
Detector, Free Flyer: Low Thrust Options
FEEP, Colloid: thrust too low, modulation range too narrow
Ion, Hall: no pulse mode, limited life (through put), modulation range too narrow
PPT Adequate thrust Pulse mode Variable pulse frequency during “continuous” mode Broad thrust modulation range: 100x may be possible (achieved
via capacitor charge level and frequency) No grid or neutralizer erosion Life extensions via:
Increased capacitor capability (reducing ratio of charge used/max charge greatly increases life)
Multiple/replenishable spark plugs
LAI MAXIM-PF May 13-17, 2002Goddard Space Flight Center
PropulsionPage 16
Final Version
Propulsion Summary
High thrust: chemical propulsion is standard technology
Low Thrust: Key Driving Requirement Thruster selection (PPT) sensitive to combined flight dynamics
and ACS requirements No current technologies exist which meet requirements PPT unit flight demonstrated on EO-1 Significant life extension required for any “electric” technologies
