Wear Control Cycle
From hnett@jw.estec.esa.nl Tue Nov 5 08:12:47 2002
Date: Wed, 30 Oct 2002 20:01:29 +0100 (MET)
From: Herbert Nett
To: rs95@leicester.ac.uk
Cc: mict@jw.estec.esa.nl
Subject: [ENVISAT:mict] Re: A small problem with l1b spectra
- for info also to MICT group -
hi Reinhold,
We received the L1B file for orbit 2880. What you see is indeed a 'wear control
cycle', WCC, in a which MIPAS looks at the internal blackbody for a short
commanded 'special event' scan.
These WCCs are currently programmed every 5 orbits (absolute orbit number
ending with '0' and '5'), in order to re-distribute the lubrication along the
rotating elev. scan spindle.
Two scans are affected, the first one is a nominal mode one which is truncated
due to the commanded WCC and the second one the WCC scan itself.
In order to properly detect truncated or 'special event' scans, perform two
checks:
1. check no. of sweeps in actual scan (field #5 in structure ADSR)
2. check instrument mode/activity (field#13 in MDSR)
'39169' is code for 'nominal mode' activity
'39172' is code for 'special events' activity (can be rearward or sideways)
(this information will be included in next Level 1B IODD update)
I hope this helps
Herbert
Pitch Jump
From hnett@jw.estec.esa.nl Tue Nov 5 14:30:02 2002
Date: Fri, 1 Nov 2002 18:11:30 +0100 (MET)
From: Herbert Nett
To: thomas.clarmann@imk.fzk.de
Cc: B.Carli@ifac.cnr.it, piera@mipasone.iroe.fi.cnr.it,
ridolfi@ms.fci.unibo.it, carlotti@ms.fci.unibo.it, dudhia@atm.ox.ac.uk,
jjr8@leicester.ac.uk, hnett@jw.estec.esa.nl
Subject: Re: MIPAS mispointing event / Orbit 2083
hi Thomas,
Please find response by F. Diekmann/ESOC, on 'pitch jump' event you saw in
orbit 2083.
best regards
Herbert
> Frank,
>
> in effect what happened on day 2002.205 around 14.54 UTC looks very much like
> the problem described in AR ENV_000333, i.e. a discontinuity in the pitch
> attitude (X axis) occurring immediately after updating the on-board orbit
> model coefficients via the PSO TCH.
>
> The pitch "jump" (that must be in the order of 10-20 mdeg) seems to be
> recovered by the control within a couple of minutes, and it can be therefore
> in principle noticed by the most accurate instruments.
>
> The reason for this is now under investigation. Note that according to the
> current theory, we might see such a jump other times (potentially every time
> we uplink a PSO TCH).
>
> In any case I would exclude this a MIPAS problem.
>
> I'll keep you informed about the proceedings of the investigations.
>
> Regards,
