Structures in Space Systems Roles o technologies Shielding Multifunctional structures Thermal, radiation, glint Deployment and geometry Maintaining System Geometry maintenance Carrying loads Deployable booms o applications Mesh antennas Power and thermal management Membrane structures Aperture forming Inflatables Spacecraft backbone Tethers ssues Formation Flight(virtual structure Light-weighting Structural dynamics Thermal distortion
Structures in Space Systems Structures in Space Systems Roles — Shielding — Thermal, radiation, glint — Maintaining Syste m Geometry — C arrying Loads Applications — Power and thermal m anage m ent — Aperture forming — Spacecraft backbone Issues — Light-weighting — Structural dynamics — Therm al distortion Technologies — Multifunctional Structures — Deploym e nt and geo metry maintenance — Deployable booms — Mesh antennas — Membrane structures — Inflatables — Tethers — Formation Flight (virtual structure)
Deployment and geometry Maintenance o Deployable membranes Used for solar arrays. sunshields decoys Being researched for apertures starting at rf and eventually going to optical o Inflatables First US satellite was inflated(ECHO D) Enables a very large deployment ratio deployed over stowed dimension Membranes stretched across an inflated torus Outgassing and need for gas replenishment has led to ultra-violet cured inflatables that rigidize after being exposed to the UV from the sun
Deployment and Geometry Maintenance Deployment and Geometry Maintenance Deployable Membranes — Used for solar arrays, sunshields, decoys — Being researched for apertures starting at RF and eventually going to optical Inflatables — First U S satellite was inflated (ECHO I) — Enables a very large deploy m ent ratio — = deployed over stowed dimension — Membranes stretched across an inflated torus — Outgassing and need for gas replenishment has led to ultra-violet cured inflatables that rigidize after being exposed to the UV from the Sun
Sa Deployment and Geometry Maintenance o Truss structures High strength to weight ratio due to large cross-sectional area moment of inertia Moment= el ax o Deployable booms able engineering a bearing ring at the mouth of the deployment canister deploys pre- folded bays in sequence EX SRTM mission on Shuttle Handout gives key relationships between I, El and truss diameter °ota/ system mass canister mass fraction
Deployment and Geometry Maintenance Deployment and Geometry Maintenance Truss Structures — High strength to weight ratio due to large cross-sectional area mom ent of inertia Deployable Booms (ABLE Engineering) — A bearing ring at the m outh of the deployment canister deploys pre-folded bays in s equence — EX: SRTM mission on Shuttle Moment = EI ∂2 w ∂x 2 Handout gives key relationships between l, EI and: •truss diameter •total system mass •canister mass fraction
Deployment for Aperture Maintenance o aperture physics requires large dimensions for improved angular resolution 6.=1.22-= D B Large area for good sensitivity (SNR) o Options include Filled apertures Deployed membranes ( Courtesy of the European Space Agency. Used with permission. Deployed panels Sparse apertures Deployed booms Formation fown satellites
Deployment for Aperture Maintenance Deployment for Aperture Maintenance Aperture physics requires: — large dim ensions for improved angular resolution — Large area for good sensitivity (SNR) Options include: — Filled Apertures — Deployed m e mbranes — Deployed panels — Spars e Apertures — Deployed boom s — Formation flown satellites θ r = 1.22 λ D = λ B (Courtesy of the European Space Agency. Used with permission.)
Origins Telescope Dynamics and Controls PSD and cumulative RMS Total OPD(int I) Disturbance Contribution Frequency (Hz) Normalized Sensitivities of Total OPD (int I)RMS value w.r. t to physical parameters
Origins Telescope Dynamics and Controls Origins Telescope Dynamics and Controls