Q. How quickly does the data appear on the CSDSweb Quicklook Plots pages?
Is near-real-time data available?
A. Cluster is not intended as a near-real-time mission. During normal operations
Cluster only makes use of a single groundstation to communicate with all four
spacecraft. This means that data are stored onboard and then transferred to
the ground some time later. Data will normally appear on these pages anything
from an hour up to several days after acquisition.
Q. There are long gaps in the data. Why is this?
A. Due to onboard storage, telemetry and ground segment constraints
science data cannot be acquired continuously throughout the orbit. On average
data is taken for about 50% of an orbit.
Q. Sometimes there is data from some instruments but not others.
A. There can be many reasons for this. Some instruments are not operated
in particular regions to protect them from radiation damage or due to operational
constraints (e.g. inter-experiment interference). Instruments may be operating
in modes that do not provide the data used to generate the quicklook plots. There
may be a problem with the quicklook system retrieving or processing the data.
Q. The Spacecraft Potential from EFW seems to be available almost all the
time. How is this possible given the answers above?
A. The S/C potential is generated from the WEC housekeeping data. Unlike
the science data required for the other products, housekeeping data is acquired
throughout the whole orbit.
Q. Who decides when data is taken?
A. The Cluster Science Working Team, led by the Project Scientist, draws
up a Master Science Plan for each spacecraft constellation (approx. 6-month
period). JSOC and ESOC then feed in operational constraints and the plan is
iterated with the PI teams to define the instrument modes that will be used.
A more detailed description of this process is available at JSOC.
Q. If I close and restart my browser I sometimes see more data than if I
just use the submit button.
A. The most likely explanation is that the plot has been updated as
a result of new data but that you are still accessing an older version that
has either been cached in your browser or possibly in a proxy server. One solution
that may help is to change your browser configuration so that it always checks
for updated files (the default setting is often set to check once each session).
We are looking at an update to the quicklook system that will help alleviate
this problem.
Q. When running in auto-update mode the plots do not change even though the
page is refreshed.
A. See previous answer.
Q. Is the data used to generate the quicklook plots available?
A. The simple answer is no. The quicklook system does not make use of
the most up-to-date processing algorithms or calibration files and produces
data that has not been validated or verified by the PI teams. Therefore it has
been decided that the data used to generate the plots will not be made available.
Q. Can I present the quicklook plots at conferences or include them in publications?
A. See the disclaimer at the bottom of each plot page. The data is not
considered to be of publication quality and should not be used as the basis
of a scientific study without discussion with the relevant PI teams (who will
be in a position to provide higher quality products).
Q. The CSDSweb Quicklook Plots home page does not display correctly in Netscape.
A. This page has been tested in both IE4 and Netscape 4 (windows and
unix) and will display correctly provided you have style sheets enabled. We
have seen some strange results if you re-size the browser window under Netscape
on Unix. Earlier versions of both IE and Netscape should be detected and you
will be redirected to the text-only contents page.