content long 18-January-2019 14:42:30


Design requirements

Spacecraft design

The original Cluster mission had a unique set of design requirements:

  • The four spacecraft had to be identical, the first time that ESA had been required to build spacecraft in true series production
  • To reach their operational orbits and to maintain the predefined separation distances between the satellites requires large quantities of propellant, more than half the spacecraft's mass
  • The mission orbits selected impose eclipse durations of up to four hours, a major design driver for the thermal-control, power and structural subsystems
  • The scientific payload required a high degree of electromagnetic cleanliness

Most design elements remain essentially unchanged for the replica Cluster mission, except for those elements directly affected by the change of launch vehicle to two Soyuz rockets.

Key parameters

Spin rate:

15 rpm

Spacecraft diameter:

2.9 m

Spacecraft height:

1.3 m

Dry mass:

550 kg

Propellant mass:

650 kg

Mass allocated to payload:

72 kg

Solar array power:

224 W

Silver Cadmium battery capacity:

80 Ah

Power allocated to payload:

47 W

Telemetry downlink bit rate:

2 to 262 kbit/s

Last Update: 16 March 2006

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