<p>The main reason appears to be to prevent any icing up and contamination of the mirrors and other optical coponents with water and other "non-volatile residues", which would be extremely detrimental to the UV performance.</p>

<p>Emissivity at 270K is not too much of an issue since the instrument only works out to 2 microns.</p>

<p>The issue is briefly discussed in section 8.1.10 of the <a href="https://asd.gsfc.nasa.gov/luvoir/reports/LUVOIR_FinalReport_2019-08-26.pdf" rel="nofollow noreferrer">LUVOIR final report</a>.</p>

CC BY-SA 4.0
2020-04-01T14:12:26.377Z
2020-04-01T15:57:19.060Z
2020-04-01T15:57:19.060Z
ProfRob
<p>From the Wikipedia page about LUVOIR design:</p>

<blockquote>
  <p>To enable the extreme wavefront stability needed for coronagraphic observations of Earth-like exoplanets, the LUVOIR design incorporates three principles. [...] . Third, the telescope is actively heated to a precise 270 K (26 °F) to control thermal disturbances.</p>
</blockquote>

<p>I always thought the chiller a telescope mirror, the better. Why is LUVOIR heated then? </p>

<space-telescope>
Why is LUVOIR actively heated?
seldon
# Why is LUVOIR actively heated?

(Asked by: username_0 on 2020-04-01)

From the Wikipedia page about LUVOIR design:

> To enable the extreme wavefront stability needed for coronagraphic observations of Earth-like exoplanets, the LUVOIR design incorporates three principles. [...] . Third, the telescope is actively heated to a precise 270 K (26 °F) to control thermal disturbances.

I always thought the chiller a telescope mirror, the better. Why is LUVOIR heated then?

**Tags:** space-telescope

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## 1 answers

### Answer by username_1 on 2020-04-01. Score: 4 | Accepted answer

The main reason appears to be to prevent any icing up and contamination of the mirrors and other optical coponents with water and other "non-volatile residues", which would be extremely detrimental to the UV performance.

Emissivity at 270K is not too much of an issue since the instrument only works out to 2 microns.

The issue is briefly discussed in section 8.1.10 of the [LUVOIR final report](https://asd.gsfc.nasa.gov/luvoir/reports/LUVOIR_FinalReport_2019-08-26.pdf).


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