Micro Arcsecond X-ray Imaging Mission (Maxim) Pathfinder

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Micro Arcsecond X-ray Imaging Mission (Maxim)
Pathfinder

• Overview
• John Martin19 August 1999

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Summary

• Maxim conceptual design presented here is an
  early design which can be a baseline for further
  development
• Maxim requires a class of formation flying which
  is new to us
• Landsat-7 and EO-1 will fly in the same orbit
  with a controlled separation, but no co-alignment
  on a common target
• Constellation-X will fly with multiple satellites
  in the same orbit, co-aligned to a common target,
  but no separation requirement
• Other missions have proposed multiple satellites
  in slightly different orbits, with separation
  managed but varying throughout the orbit
• Maxim requires 2 satellites to be maintained with
  a fixed separation and co-aligned for periods of
  as much as 7 days
• Maxim requires levels of pointing precision and
  stability which are a challenge

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Larger Concerns

• Flight Dynamics
• Selected use of drift-away orbit
• Simple cases appear to be manageable
• Not sure of the control authority required for
  the 5 case
• Guidance, Navigation control
• Appears feasible, provided the instrument is used
  to close the loop for maintaining pointing
  stability
• More study needed of use of the pulse plasma
  thrusters
• More study needed of the post-launch scenario for
  separation and orbit modifications needed to
  achieve final configuration
• Propulsion
• Can meet the pointing needs using a combination
  of coarse (newton range) and fine (mnewton range)
  thrusters
• Slewing takes a lot of fuel
• Initial separation easier with 2 launch vehicles
  or a significant wait (¼ to ½ orbit) after launch

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Lesser Concerns

• Mechanical
• Can fit into a single launch vehicle with an
  extended fairing
• 1 vs. 2 launch vehicles becomes a
  cost/propellant/wait-time tradeoff
• Conceptual design for launch and orbital deployed
  configurations
• Thermal
• Stable orbital environment leads to a
  straightforward design
• Concern exists that the 5 pointing offset may
  produce a banana effect on the optics satellite
• Further study of the potential use of a composite
  structure for the optics satellite is indicated
• Power
• Full-sun leads to straightforward design
• Data Systems
• Data return from 40,000,000 km is possible using
  either 13m dishes or the DSN 34m network
• CDH approach based on the SMEX-lite design, but
  using a Power PC 750 processor