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Team Force Field. Leslie Chapman Scott Cornman Adam Johnson Richard Margulieux Brandon Phipps. Presentation Outline. Introduction Mission Objectives Background Mission Mission Profile Trade Tree Spacecraft Mission Profile Lander Orbiter
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Team Force Field Leslie Chapman Scott Cornman Adam Johnson Richard Margulieux Brandon Phipps
Presentation Outline • Introduction • Mission Objectives • Background Mission • Mission Profile • Trade Tree • Spacecraft • Mission Profile • Lander • Orbiter • Communication Link and Command & Data Handling • Advantages
Introduction Mission Objectives • Primary Objectives • Determine the trajectory of Apophis • Determine the seismology of Apophis • Secondary Objectives • Laser mapping of Apophis • Close imaging of Apophis
Introduction Past Missions • Galileo • Successful approach of 951 Gaspra, 243 Ida and Dactyl • Solid state imager, Near IR spectrometer • Dawn • 3 DS1 Xenon Ion Engines, 3 Visual sensors, Visual and IR spectrometer, Gamma Ray and Nuetron spectrometer • Phobos 1,2 • Unsuccessful study of Phobos and Deimos • Two landers, hopper, long-lived, spectrometer, seismometer, penetrometer • Orbiter houses IR, visual, Near IR spectrometer, Gamma, X-ray sensors • Deep Impact • Successful flyby and impact event of comet 9p/Tempel, extended mission to 85P/Boethin • High Resolution Imager, Medium Resolution Imager, Impactor Targeting Sensor, Infrared Spectroscope • 650kg/370kg impacter
Introduction Past Missions • NEAR Shoemaker • Successful orbit and landing on Eros, communicated for 2 weeks before being shutdown • Mass: 487kg • Approach Distance: 200km, 35km, 5-6km, 2-3km, land at 1.5-1.8m/s • Reaction wheels and hydrazine thrusters, 1800 W solar power, Ni-Cd battery pack, IMU, gyros, sun sensors and star tracker • X-ray/gamma ray spectrometer, Near-infrared imaging spectrograph, Multi-spectral camera fitted with a CCD imaging detector, Laser rangefinder, Magnetometer, Radio science experiment to determine gravity field • JAXA Hayabusa • Successful heliocentric orbit near and two close approaches to 25143 Itokawa, failed deployment of MINERVA, on return trajectory to Earth • Mass: 380kg (MINERVA: 591g) • Approach Distance: 20km, 44m, ? • 4 Xenon Ion Engines, Reaction wheels (failed on orbit), thrusters • Multiband imaging camera, Laser altimeter, Near-infrared spectrometer, X-ray spectrometer
Trade Tree Launch Vehicle Piggyback with Private LV Piggyback with Government Use exclusive LV
Trade Tree Propulsion Earth escape Rendezvous with Apophis Chemical Low Thrust Solar Sails Electrical
Trade Tree Power Solar Fuel Cells Nuclear RTG
Trade Tree 3-Axis Attitude and Translational Control Cold Gas Momentum Devices Traditional Augmented CMG Reaction Wheel Electric Chemical PPT Hall’s Effect Thrusters Mono Bipropellant
Trade Tree Proximity Operations Combination of stand-off to deploy Complete Stand-off Complete Lander
Trade Tree Complete Stand-off Stand-off Orbit Single Multiple Single Multiple
Trade Tree Partial Deployment Main Lander with Orbiting Link Main Orbiter with Lander(s) • Orbiter • - Radios • Camera • Solar Panels • Lander • Transponder • Camera • Laser mapping device • Seismology detector • Radio • Solar Panels • Orbiter • - Radios • - Transponder • Camera • Laser mapping device • Solar Panels • Lander • Transponder • Seismology detector • Radio • Solar Panels
Trade Tree Complete Lander Single Multiple
Trade Tree Landing Systems Barbed Attachment Hooks Skids Impactor Harpoon and Winch Gossamer Net Pyramid Design Cubic Design
Trade Tree Mission Critical Components Seismic Measurement Method Tracking Architecture Transponder(s) on Lander(s) Transponder on Stand-off Vehicle Active Ping and Listen Passive Seismometer
System Description • Orbiter with Landers • Rendezvous with Apophis • Landers deploy to Apophis • 200-300 kg to Earth Orbit • ~100 kg at Apophis
System Description • Earth Operations • Launch • Start-up and system checkout • Trajectory • Plane change and escape velocity burn • Orbit transfer burn and course corrections • Initial Apophis Operations • Stand-off at safe distance • Initial imaging, mapping, data transfer • Landing site selection from Earth • Apophis Close Approach and Deployment • Incremental Approach to Apophis • Hover above Apophis surface, deploy landers • Orbiter return to heliocentric orbit • Landers deploy, gather initial data and transfer • Earth Close Approach Event • Tracking with transponders • Orbiter to Earth and Apophis attitudes • Shifting morphology seismometer readings • Data transfer to Earth Mission Profile
The Landing Problem • Close approach of Apophis by orbiter • Spring loaded deployment of landers Orbiter Apophis Surface
Lander Sub-systems and Instruments Step 1 Step 2 Step 3 • Landers • Open Tetragon to automatically orient • Equipped with: • Shallow pitch drill • Acoustic equipment • Cross-link radio • Transponder • Solar panels
Orbiter Subsystems • Orbiter Systems • Power: Solar Panels • Stable, established source of energy • No consumables • Limited Degradation • 1 kW requires ~7 m2
Orbiter Subsystems • Reaction Wheels • Minimum of 3 reaction wheel assemblies • Provide X,Y, & Z attitude control • Controlled from 1 control box • Pulsed Plasma Thruster • Attitude control, low thrust maneuvers • Solid Propellants • High Isp, low impulse • Uses ionized, accelerated plasma • Energy Storage Unit • Ignitor • Fuel Rod • Plasma Accelerator
Orbiter Instruments • Laser mapping device • Transponder • Star Tracker • IMU, Gyros • Radios • Crosslink with landers • Uplink • Downlink • High bandwidth • Low bandwidth • Imagers • Near IR • Visual
Communication Link and Command & Data Handling Communication Link • Uplink radio • Downlink radio • Cross-link • Transponders Command and Data Handling • Solid state storage devices • Semi-autonomous (command to begin programmed events) • Ability to upload new command sets Earth
Advantages: Landing System • Redundancy: multiple landers can be deployed • Landing orientation does not matter • Hooks on all vertices discourage rebound off surface • Robust landing structure to protect delicate equipment • Spring loaded deployment results in low reaction force on orbiter • Optical equipment remains on orbiter to avoid impact of landing
Solar Panels Proven technology Stable energy source Semi-autonomous command Allows for actions with limited communication Flexibility Communications Link Constant line of sight Imaging B/W for low data rates Near IR for composition data 3-Axis Control Reaction Wheels Small, prebuilt assemblies No consumables PPT Small form factor High Isp Low Impulse Tracking Scheme Constant line of sight Large power source Simple transformations Advantages: Orbiter Subsystems