Instrument, Spacecraft, and Launch Overview Joan Howard Ball Aerospace

Instrument Requirements

Ball Heritage Currently building SIRTF CTA and instrument which uses Ge:Ga FPA’s –Past CDR in subassembly test –No major technical showstoppers IRAS flying successfully –very similar from a cryo design - only smaller Conceptually simple design –simple electronics, tested FPA’s, small/few element optics, but…. –Cryo design never simple

Spacecraft Requirements Low Cost - less than $15M? Accept >125 kg instrument Provide > 30 Watts of power to payload Pointing Stability < 24 seconds per data acquistion Fit into selected Launch Vehicle Data Storage: 200 Mbytes

Spacecraft Key Performance Requirements Description X-12M SMEX LITESA-200S MiniStar Spacecraft Bus Mass 65.6 kg75kg 98kg Payload Mass Capability200 kg91kg200kg180kg Available Payload Power> 100 W150W60W17.5W ACS Configuration 3-axis stabilized3 axis zero momentum Gravity Gradient Attitude Knowledge 28  rad5  rad.5 degrees Attitude Control 32  rad96  rad10 degrees Payload Data Storage 256 Mbytes130 Mbytes8Gbyte 3Mbytes Communications S-BandS-BandS-bandS-band Telemetry Rate 4Mbps2.25Mbps10Mbps1 Mbps

Equipment Shelf Provides Ample Area For Subsystem Units

S/C Selection Meets minimum requirements Lowest total cost –nearly all COTS buses will need changes –integration issues –heritage of performance: technical, cost, schedule Willing to work with team Selection not mandatory for 1st round - a solution, not the solution needed

Issues/risks/options Need good story for aperture cover - esp. after WIRE Light shade a key driver in itself and for cryo design Star tracker vs. gyro battery size vs. eclipse CPU capabilities/memory - on orbit computation vs. downlink configuration drivers: LV, COTS, star tracker location, timeline, launch date

Launch Options