Utente:Vale maio/Sandbox2: differenze tra le versioni

Versione delle 21:29, 24 feb 2009

Versione delle 21:37, 24 feb 2009

Riga 60:

| Sensibilità (mK s<math>^{1/2}</math>) || 0.8 || 0.8 || 1.0 || 1.2 || 1.6

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The WMAP's base is a 5.0m-diameter [[solar panel]] array that keeps the instruments in shadow during CMB observations, (by keeping the craft constantly angled at 22 degrees, relative to the sun). Upon the array sit a bottom deck (supporting the warm components) and a top deck. The telescope's cold components: the focal-plane array and the mirrors, are separated from the warm components with a cylindrical, 33&nbsp;cm-long thermal isolation shell atop the deck.<ref name="2003Bennett" />

Passive thermal radiators cool the WMAP to ca. 90 degrees K; they are connected to the low-noise amplifiers. The telescope consumes 419 [[watt|W]] of power. The available telescope heaters are emergency-survival heaters, and there is a transmitter heater, used to warm them when off. The WMAP spacecraft's temperature is monitored with [[platinum resistance thermometer]]s.<ref name="2003Bennett" />

Riga 67 ⟶ 65:

The WMAP's calibration is effected with the CMB dipole and measurements of [[Jupiter]]; the beam patterns are measured against Jupiter. The telescope's data are relayed daily via a 2GHz [[transponder]] providing a 667[[kbit/s]] downlink to a 70m [[Deep Space Network]] telescope. The spacecraft has two transponders, one a redundant back-up; they are minimally active — ca. 40 minutes daily — to minimize [[radio frequency interference]]. The telescope's position is maintained, in its three axes, with three [[reaction wheel]]s, [[gyroscope]]s, two [[star tracker]]s and sun sensors, and is steered with eight [[hydrazine]] thrusters.<ref name="2003Bennett" />

La base del WMAP è costituita da un [[pannello solare]] di 5 metri di diametro, il quale tiene la sonda costantemente all'ombra durante il rilevamento della radiazione di fondo .<ref name="">Questo avviene mantenendo la sonda ad un'angolatura costante di 22 gradi rispetto al Sole</ref> Al di sopra del pannello si trova l'apparato di raffreddamento della sonda. Tra questo apparato di raffreddamento e gli specchi, è posizionato un cilindro per l'isolamento termico, dellla lunghezza di 33 cm.<ref name="2003Bennett" />

== Launch, trajectory, and orbit ==