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SLR-Mail No.880

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Date:2002-01-11 09:09:00
Sender:Carey Noll <Carey Noll <noll@cddisa.gsfc.nasa.gov>>
Subject:[SLR-Mail] No. 880: JASON Tracking
Author:Carey Noll
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SLR Electronic Mail 2002-01-11 09:09:00 UTC Message No. 880
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Author: Carey Noll
Subject: JASON Tracking

Dear Colleagues:

As most of you are already aware, JASON, the follow-on to the
TOPEX/Poseidon Mission, was launched on December 7th, 2001.
The final stages of maneuvering JASON into the tandem orbit with
TOPEX/Poseidon are underway. In its final orbit, JASON will follow
TOPEX/Poseidon by about one minute in time. The orbit maneuver should
be completed today, January 10th, 2002 and predictions will be
forthcoming shortly thereafter.

It is very important that we track both TOPEX/Poseidon and JASON
intensively. Since these satellites will be so close, we are
requesting that stations track full passes of each satellite, but
alternate between satellites for every successful pass. (For
example, for the first pass, track JASON for a full pass,
and then on the next pass, track TOPEX for the full pass.) We may try
something more complicated later, but right now it is very important
to get as much data as possible.

The official SLR tracking starts on Monday, January 14. You should
acquire the satellite prior to that date so that you can be up and
running smoothly on Monday. Please take note, the retroreflector
cross-section on JASON is considerably smaller than that of
TOPEX/Poseidon so you may need to make some accommodation in your
ranging procedures.

JASON is an oceanography mission to monitor global ocean circulation,
study the tie between the oceans and atmosphere, improve global
climate predictions, and monitor events such as El Niño conditions
and ocean eddies. JASON will have GPS tracking. The SLR data will
support POD, provide the crucial centering of the orbit relative to
the Earth´s center of mass and provide the absolute calibration of
the radial orbit error.

Important JASON orbit information:

Launch: Dec 7, 2001
Altitude: 1336 km
Inclination: 66.0 deg
Eccentricity: ~0.0
SIC #: 4378
COSPAR #: 0105501
NORAD #: 26997
Npt Bin Size: 15 secs

The ILRS priority will be set at four, above TOPEX, but the alternate
tracking strategy should be used.

Acquisition data will be available as soon as we are notified by CNES
that the satellite is in its final orbit.

Good luck and best regards,

Carey Noll.
Secretary, ILRS Central Bureau

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Ms. Carey Noll Manager, Crustal Dynamics Data Information System (CDDIS)
Code 920.1 E-mail: noll@cddisa.gsfc.nasa.gov
NASA GSFC Voice: (301) 614-6542
Greenbelt, MD 20771 Fax: (301) 614-5970
USA WWW: http://cddisa.gsfc.nasa.gov/cddis_welcome.html
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From: Carey Noll

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