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Mission Requirements

MidSTAR Program Requirements flow from The MidSTAR Program Mission Statement and merge with the MidSTAR Program Design Decisions to produce the MidSTAR-1 Mission Requirements. These in turn, merge with the MidSTAR-1 Mission Design Decisions to produce the Spacecraft Subsystem Requirements. 

Primary mission requirements are:

  1. MidSTAR mod 1 must obey the physical, electrical and environmental constraints of the ESPA ring; MidSTAR mod 2 must obey the physical, electrical and environmental constraints of the CAPE system;
  2. Three-axis stabilization available for missions requesting it;
  3. Solar energy collection maximized, battery depth-of-discharge (DOD) consistent with two-year mission life;
  4. PC-based Command & Data Handling (C&DH) System with open source software;
  5. Uplink and downlink frequencies in military spectrum;
  6. Communications data rates maximized;
  7. Active thermal control where required.

Mission requirements have been chosen with the intent of accommodating as many SERB-approved payloads as possible. The 2002 SERB List was subjected to a frequency analysis to determine a range of values that MIDSTAR could support:

  1. 0-300,000 cm3 of volume accommodates for 80% of experiments;
  2. 0-125 kg, the mass limit for mod 2, accommodates 70% of experiments;
  3. 0-100W average power accommodates 70% of experiments; and
  4. 0-100 kbps data rate satisfies 90% of experiments.

The baseline configuration of MidSTAR-class satellites will assume maximum capacity in all onboard systems. Trade-offs will be made in the design of specific spacecraft as necessary to meet the needs of the payloads manifested.

Design Decisions

  1. Uplink 1.767 GHz with an IF frequency of 435 MHz;
  2. Downlink 2.20226 GHz;
  3. Gaussian Mean Shift Key modulation;
  4. 68.4 kbps or better data rate;
  5. Open source software based on Linux operating system.

MidSTAR-1 Mission Requirements

  1. MidSTAR-1 must obey the physical, electrical and environmental constraints of the ESPA ring;
  2. Solar energy collection maximized, battery depth-of-discharge (DOD) consistent with two-year mission life;
  3. PC-based Command & Data Handling (C&DH) System with Linux operating system;
  4. Uplink 1.767 GHz, downlink 2.20226 GHz;
  5. 68.4 kbps or better GMSK.

Design Decisions

  1. No attitude control or determination;
  2. No active thermal control.
  3. Mass not to exceed 120 kg.
  4. 492-km circular orbit, 46 degree inclination. No requirement on right ascension of the ascending node.