NASA Logo Wilkinson Microwave Anisotropy Probe
NASA Logo, National Aeronautics and Space Administration

WMAP Mission Specifications

The following tables give the high-level technical specifications for the WMAP instrument and observatory. More details are available by following the linked items in the tables.

WMAP Instrument

Frequencies (GHz) 22 30 40 60 90
Wavelengths (mm) 13.6 10.0 7.5 5.0 3.3
# of channels 4 4 8 8 16
Resolution (FWHM, degrees) 0.93 0.68 0.53 0.35 <0.23
Sensitivity (µK, 0.3° x 0.3° pixel) ~35 ~35 ~35 ~35 ~35
Radiometer Differential pseudo-correlation with polarization
Reflectors Dual Gregorian; 1.4 m x 1.6 m primaries
Thermal Passive radiative cooling to < 95 K
Structure Composite / aluminum
Focal plane 3.5° x 3.5° field of view
Pointing accuracy 0.6° control (elevation); 1.8' knowledge

WMAP Observatory

Redundancy Primarily single string
Lifetime 27 months; fuel limit > 3 years
Mass 840 kg
Orbit L2 (1-10° Lissajous orbit)
Trajectory Lunar assist with phasing loops
Communications 2 omnis during phasing loops
Medium gain antenna for downlinks after lunar flyby
Uplinks Once weekly to schedule downlinks
Downlinks Once daily; Deep Space Network always in view
Downlink data rate from L2 667 kbps to 70 m dish; 16 min/day
Propulsion Blow-down hydrazine with 8 thrusters
Attitude control 2 star trackers, 2 gyros, coarse & fine Sun sensors, 3 reaction wheels for scanning
Spin rate / Precession rate 0.464 rpm (~2 min per spin)
0.017 rpm (1 hr per precession); 22.5° cone about WMAP-Sun line
Structure Composite / aluminum
Power 419 W; 3.1 m2 GaAs/Ge array, 22.5° off full Sun
23 A-hr NiH battery; no eclipses
Thermal Passively cooled with radiators, solar array shades instrument; MLI and gamma-alumina cylinder isolates spacecraft from instrument
  • wmap.gsfc.nasa.gov
  • Webmaster: Britt Griswold
  • NASA Official: Dr. David T. Chuss
  • Page Updated: Friday, 04-16-2010
NASA Logo