|
|
| (21 intermediate revisions by 4 users not shown) |
| Line 1: |
Line 1: |
| − | This is the load test page. Please write some stuff in here and try to save your edits.
| + | == Section 1 == |
| | | | |
| − | (Note: Adapted from Tauber et al. 2010, A&A 520, A1 and Ade et al. 2011, A&A 536)
| + | In section [[#para:ex|3]] we can learn something. |
| − | ==Introduction==
| |
| − | The performance of the Planck instruments in space is enabled by their low operating temperatures, 20 K for LFI and 0.1 K for HFI, achieved through a combination of passive radiative cooling and three active mechanical coolers. The scientific requirement for very broad frequency coverage led to two detector technologies with widely different temperature and cooling needs. Active coolers could satisfy these needs; a helium cryostat, as used by previous cryogenic space missions (IRAS, COBE, ISO, Spitzer, AKARI), could not. Radiative cooling is provided by three [[V-groove]] radiators and a large [[telescope baffle]]. The active coolers are a [[sorption cooler|hydrogen sorption cooler]] (<20 K), a <math>^{4}</math>He [[4K cooler|Joule-Thomson cooler]] (4.7 K), and a <math>^{3}</math>He-<math>^{4}</math>He [[dilution cooler]] (1.4 K and 0.1 K). The flight system was at ambient temperature at launch and cooled in space to operating conditions. The HFI bolometer plate reached 93 mK on 3 July 2009, 50 days after launch. The solar panel always faces the Sun, shadowing the rest of Planck, and operates at a mean temperature of 384 K. At the other end of the spacecraft, the [[telescope baffle]] operates at 42.3 K and the [[telescope primary mirror]] operates at 35.9 K. The temperatures of key parts of the instruments are stabilized by both active and passive methods. Temperature fluctuations are driven by changes in the distance from the Sun, sorption cooler cycling and fluctuations in gas-liquid flow, and fluctuations in cosmic ray flux on the dilution and bolometer plates. These fluctuations do not compromise the science data.
| |
| | | | |
| − | The contrast between the high power dissipation in the warm service module (<math>\sim</math> 1000 W at 300 K) and that at the coldest spot in the satellite (<math>\sim</math>100 nW at 0.1 K) are testimony to the extraordinary efficiency of the complex thermal system which has to achieve such disparate ends simultaneously while preserving a very high level of stability at the cold end.
| + | == Section 2 == |
| | | | |
| − | ~Xavier
| + | Some text. |
| | | | |
| | + | == Section 3 == |
| | | | |
| − | test
| + | First para. with some text |
| | | | |
| − | again
| + | [[anchor|para:ex]] |
| − | | + | This is the paragraph I want to reference. |
| − | Luis was here again
| |
Latest revision as of 16:20, 4 October 2012
Section 1
In section 3 we can learn something.
Section 2
Some text.
Section 3
First para. with some text
para:ex
This is the paragraph I want to reference.
