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SuperNova/Acceleration Probe SNAP Study. Mechanical. Dave Peters George Roach June 28, 2001. ...a man who's willing to make a decision in the first place can always make another one to correct any mistake he's made. Harry S. Truman. Topics. Launch Vehicle Volume Comparisons - PowerPoint PPT Presentation
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Mechanical
SuperNova/Acceleration Probe
SNAP Study
Dave Peters
George Roach
June 28, 2001
...a man who's willing to make a decision in the first place can always make another one to correct any mistake he's made. Harry S. Truman
SNAP Study, June 28, 2001
Goddard Space Flight CenterMechanical
Page 2
Launch Vehicle Volume Comparisons Configurations
Launch Deployed Bus layout
Mechanical Mass, Cost, & TRL Mass Properties Issues and Concerns Back-ups
Launch vehicle lift capacity comparisons
Topics
SNAP Study, June 28, 2001
Goddard Space Flight CenterMechanical
Page 3
Launch Vehicle Volume Comparisons
Delta II
Atlas EPF Delta III SeaLaunch
6.57 M
SNAP Study, June 28, 2001
Goddard Space Flight CenterMechanical
Page 4
Deployed Configuration
Propulsion Tanks
Sub-system
electronics
Secondary Mirrorand
Mount
Optical BenchPrimary Mirror
ThermalRadiator
Solar ArrayWrap around, body mounted
50% OSR & 50% Cells
Detector/CameraAssembly
SNAP Study, June 28, 2001
Goddard Space Flight CenterMechanical
Page 5
Bus Layout
Propulsion Tanks
5# thrusters(4 sets of 2)
Sub-system electronics
Sub-system electronics
Sub-system electronics
FIDO electronics
Momentum Wheels
(4 Ithaco “B”)
Points to consider• Mass balance• Thermal • Access for servicing propulsion tanks• Integration and test access
SNAP Study, June 28, 2001
Goddard Space Flight CenterMechanical
Page 6
Mechanical Mass, Cost, & TRL(composite structure assumed)
Mass (kg) Bus Structure
Thrust tube 33 (can be lower - not structural)
Plates 31 Misc. brackets, clips, etc. 79
143 total
TRL #6 : System/subsystem model or prototype demonstration in a relevant environment (ground or space)
Subsystem prototypes or models of the proposed bus have been successfully tested under space conditions in orbital flight, but in a bus configuration different than the proposed bus.
Bus prototypes or models will require major modifications for proposed mission. This will require flight requalification.
Proven launch vehicle to be used.
SNAP Study, June 28, 2001
Goddard Space Flight CenterMechanical
Page 7
Mass Properties
Spacecraft Lift-off
C.G………………… 23.4, -126.3, 1186.0 (mm)
Inertia’s wrt C.G. Ixx ……………… 3.6e9 Iyy ……………… 3.3e9 Izz ……………… 2.1e9
X
Y
Z
SNAP Study, June 28, 2001
Goddard Space Flight CenterMechanical
Page 8
Mechanical Issues and Concerns
RSDO Spacecraft Bus There are several “RSDO” buses that could accommodate this mission.
However, due to the unique payload instrument interface, extensive re-design of the mechanical structure is necessary. A mission unique structure will be mandatory. At this time we feel that there will be sufficient volume to accommodate the sub-system components. The main concern being the reaction wheels and their relationship to the C.G.
Mass and Volume No mass problem Volume is close on the Delta III and Atlas EPF.
This volume conflict is very slight and could be resolved by a slight reduction of the MLI Shroud Assembly
Mechanical interfaces Mission axial C.G. height within limits for launch vehicle PAF. Mission lateral C.G. are within limits for launch vehicle PAF. Mission stiffness for launch vehicle is TBD at this phase of the study.
SNAP Study, June 28, 2001
Goddard Space Flight CenterMechanical
Page 9
BACK-UPSlides
SNAP Study, June 28, 2001
Goddard Space Flight CenterMechanical
Page 10
Launch Vehicle Performance(Delta III)
-2
2700
SNAP Study, June 28, 2001
Goddard Space Flight CenterMechanical
Page 11
Launch Vehicle Performance(Atlas III)
-2
3100
SNAP Study, June 28, 2001
Goddard Space Flight CenterMechanical
Page 12
Launch Vehicle Performance(Sea Launch)
-2
3300
