Important notice about STEREO Behind
The two STEREO observatories are nearly identical with selective redundancy.
The building of the spacecraft bus and the integration of the instruments were
done by the Johns Hopkins University Applied Physics Laboratory (APL).
The two solar-powered observatories with 3-axis-stabilization, each had a mass at launch
of approximately 1,364 pounds (620 kilograms, including propellant).
The spacecraft communicate with the APL-based Mission Operations Center via
NASA’s Deep Space Network.
The significant challenge in spacecraft design is the large number and extent of
the instrument fields-of-view, coupled with the various instruments’ competing
design requirements to ensure successful science observations.
The major design drivers to support the science instrument performance are a
conductive outer surface for the energetic particle experiments, stringent
electromagnetic compatibility and interference requirements for the radio burst
tracker, and contamination control of both volatiles and particulates for the imager
The spacecraft bus consists of six operational subsystems supporting two instruments
and two instrument suites. This combination provides a total of 16 instruments per
observatory. The subsystems include: command and data handling; radio frequency
communications; guidance and control; propulsion; power; and thermal.
Key Characteristics of Twin Observatories
*1 arcsecond = 1/3,600 of a degree
- Mass: 1,364 pounds (620 kilograms)
- 3.75 feet (1.14 meters)
- 4.00 feet (1.22 meters) wide (launch configuration)
- 21.24 feet (6.47 meters) wide (solar arrays deployed)
- 6.67 feet (2.03 meters) deep
- Power consumption: 475 watts
- Data downlink: 720 kilobits per second
- Memory: 1 gigabyte
- Control – within 7 arcseconds (0.0019 degrees)
- Knowledge – within 0.1 arcsecond (0.000028 degrees)
Last Revised: Wednesday, 30-May-2007 11:20:21 EDT
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