=======================================================================
Oersted Newsletter #10, 1999 (January 28)
=======================================================================

Table of Contents
=======================================================================
1. Oersted Launch Delayed 
2. Oersted Internal Field Science
=======================================================================

-----------------------------------------------------------------------
1. Oersted Launch Delayed 
-----------------------------------------------------------------------
From: Kim Bisgaard (kib@dmi.dk)

As you may know, the launch of ARGOS, SUNSAT, and OERSTED has been
scrubbed again. The delay this time is due to an on launch pad engine
cutoff. Initial investigation shows that the cutoff was due to low
pressure in the fuel tank of a steering engine. NOT due to the weather
this time! There will be at meeting in the morning California time to
decide a new launch date.

-----------------------------------------------------------------------
2. Oersted Internal Field Science
-----------------------------------------------------------------------
From: Nils Olsen (nio@dsri.dk)


Dear Colleagues,

As mentioned in the Oersted Newsletter #6/99, I agreed to take over
the task of Oersted Main Field Modeling and coordination of the
Internal Field Science in general. This is, of course, a great
challenge, and I look forward to an exciting and fruitful
collaboration.


IN-FLIGHT CALIBRATION AND INITIAL FIELD MODELS

One of the most important issues is be to obtain a reliable in-flight
calibration of the magnetometer as a first step for providing you with
the high-quality data you are expecting. Getting experience with the
behavior of the magnetometer in space, and how to calibrate it, will
therefore have high priority during the next weeks and months.

We have asked Terry Sabaka (NASA/GSFC) to visit Copenhagen and help us
in this effort. He has agreed to come about two months after launch
for six weeks. During this period we will work on the in-flight
calibration of the vector magnetometer (combined estimation of main
field model and magnetometer parameters) as well as on the Oersted
IGRF candidate.

The decision on the calibration parameters to be used will be made by
a calibration sub-group based on the results of in-flight calibration
algorithms. There are plans for a meeting of the group a few weeks
after launch. I'll send you more information on this meeting as soon
as we have decided on the date; everybody is welcome to participate in
this meeting.

It has been suggested to publish the first Oersted Main Field Models
with the Oersted Main Field Investigators as co-authors. A first step
in this direction was the submission of an abstract for the IAGA
meeting in Birmingham. The deadline for abstract submission was
January 15, and Terry will present the Oersted IGRF candidate at the
IAGA meeting. Let's hope that the satellite will be launched soon and
that the data are as good as we expect.
The text of the submitted abstract:
    AN IGRF 2000 CANDIDATE MODEL BASED UPON OERSTED SATELLITE DATA

    T.J. Sabaka (Raytheon ITSS Corp., Lanham, MD 20706, USA, email: 
    sabaka@linus.gsfc.nasa.gov)
    Oersted Main Field Working Group

    The Danish satellite Oersted, launched in January 1999, is to provide
    the best sampling of the geomagnetic field for main field modelling
    purposes since the Magsat mission of 1980.  An IGRF 2000 candidate
    model, derived from this high-precision vector data set and
    supplemental observatory measurements, will be presented.


SELECTION OF DATA FOR THE MODELING EFFORTS

There are plans for selecting/compiling special data sets for the
internal field modeling efforts. These data sets will be accumulated
in batches of about one month, and are anticipated to contain about
3000 data points (consisting of time, position and the 3 magnetic
vector components). The data will be pre-selected according to
geomagnetic indices, but the final selection will of course be made
after visual inspection, and a good geographical coverage will be
taken care of.

-----------------------------------------------------------------------