this presentation will address the
flight operations plan for the orbiting
solar laboratory
osl it will describe utilization of the
nasa ground system and control the
observatory pointing
from instrumental workstations during a
typical
science campaign the osl will be
creating
high-resolution motion pictures of the
dynamic activities on the sun's surface
and in the overlying chronosphere
digitizing this data for real-time
transmission to the ground requires a
relatively
high data rate of 16 megabits per second
in comparison other solar imaging
satellites like
smm took still photos stored them on
board and transmitted them later at
about
32 kilobits per second or less
however the landsat satellites take even
higher resolution still
photos of the earth and transmit them in
real time at 85 megabits per second
but the total data required for landsat
is lower than for osl
because landsat takes individual scenes
only
while osl takes movies in both cases
there is too much data for a nominal
onboard storage device
tdrs is the only way to get real-time
data rate telemetry from a low
polar orbiting satellite like landsat or
osl
tdrs must point its high gain antennas
at these satellites
whenever their science data is to be
collected therefore
availability of the tdrs single access k
band ksa
links will limit the amount of science
data that osl
transmits typically tdrs
has authorized from four to eight hours
per day
on their ksa links as long as it's at
their convenience
for osl this is no problem since osl
will see the sun
100 percent of the time and we'll see at
least one tdrs satellite
97 percent of the time
during these real-time telemetry
sessions data from osl is received at
the data capture facility
dcf at the goddard space flight center
all raw data is recorded on high density
digital recorders it is processed to
level zero and forwarded to the science
operations facility
sof in near enough real time
because the osl is using nasa's standard
telepathization formats and protocols
the nasa communications network can
easily handle it within their
institutional ground system capabilities
this data output from the dcf is easily
converted into viewable movies
by the instrument or workstations and
the entire communications link is
transparent
in addition the dcf recorded data is
eventually sent to the goddard science
data processing facility
for offline bulk data processing
distribution to the scientists
and archiving
the project operations control center
park
located goddard will handle all flight
operations
this requires only an s-band link
through tdrs
during science data collection times a
single access system is available but
otherwise
a low gain multiple access system is
sufficient
whenever osl is not collecting real-time
science data
the puck is responsible for routine
maintenance and housekeeping
it must ensure that the observatory
stays pointing nominally at the sun
to keep the solar arrays lit even when
the scientists are controlling the
observatory pointing
the puck has inline control over any
uplinked commands
and it prevents any hazardous commands
osl will be available for real-time
science campaigns during nine months
each year
at pre-planned tdrs observation windows
a typical campaign is planned by the
scientists based on inputs from other
solar observatories
and requests from the osl scientists and
the solar physics community
the sof coordinates these inputs and
dictates the campaign scenario
it is possible to conduct retargeting
and near real-time science data
processing operations from the sof
a typical science observation campaign
first requires a course
pointing of the osl to a new location on
the sun
the initial course pointing can be done
with the
low rate multiple access tdrs
communications links
before the high gain tdrs antennas are
scheduled for osl
in the sof the scientists have full
sun images from ground-based
observatories displayed
on their workstations the yellow disk
shown here represents this image
the real full sun image will indicate
which local feature on the sun is
currently being viewed by the osl
and the location of the new feature to
be targeted
using a mouse the operator positions his
display window over the new location
and initiates a command to move the osl
in addition the osl must be rotated
to align the osl cameras properly for
this feature
this is also done by rotating the
display window and initiating a command
to the osl
the poc must approve all commands before
it uplinks them
then the osl will begin to reorient
itself as directed
the only data received to verify this
course pointing
is found in the spacecraft housekeeping
telemetry
that is received through multiple access
tdrs
by the park now the scientists wait for
the pre-scheduled tdrs high data rate
link
once tdrs points its high gain antenna
towards osl
the ongoing science data is relayed to
the dcf and forwarded to the sof
where it is viewed as a movie
the workstation display is replaced by
this near real-time osl data
which is a very high-resolution blow-up
of a small
area on the sun within this blow-up the
scientist can exactly locate the feature
of interest
and do the necessary fine pointing again
he moves his display window across the
image and rotates it as necessary
he initiates the appropriate command
request and the poc screens it and
uplinks it if valid
this time the image displayed on the
workstation will
update as the osl moves and the
scientists can verify
the new pointing in near enough real
time
once satisfied he can set the osl auto
track system by another
standard workstation generated command
oso will now recognize the feature in
its field of view
and track it even as it changes and
moves
since there are no eclipses oso never
loses the target
and it will track it even after tdrs
breaks contact
hours or days later when tdrs resumes
real-time science data
the feature is still centered in the osl
field of view and
once again displayed on the workstation
scientists are thus able to more easily
interpolate the missing data
because they know that this is the same
feature
in addition to auto tracking the osl has
image
stabilization systems on each of its
instruments
these systems remove any jitter in the
data caused by random vibrations of the
observatory
that might be caused by the steerable
antennas
or the reaction wheels in the attitude
control subsystem
this capability is demonstrated by these
before and after pictures taken of the
sun
using this image stabilization system at
a ground-based
observatory the jitter was introduced
mechanically
to simulate onboard vibrations of
various frequencies
and has been totally removed notice that
the data quality is degraded
by the atmospheric distortions as it is
with all ground-based observations
because of these state-of-the-art
capabilities provided by the osl
in this continuous sunlit orbit the
scientist will also be able to conduct
some near-real-time
science data processing from his
workstation as he views the data
he can select various filters for
example to emphasize the events of most
interest and
quickly evaluate his decision in this
way
he can ensure that the data being
collected back at the dcf is
just what he needs he also knows where
in the raw database it will be and
he can request only the essential data
to be bulk
processed offline this inherently will
reduce the amount of bulk data
processing required to produce
a prescribed data product
a number of types of science
observations can be accomplished
just as easily by this osl for example
some dynamic solar processors require
a quick look every so often and the data
can be collected during
short tdrs contacts other events require
a continuous look for several hours to
capture the entire process
tdrs has assured at least a three hour
science data contact
every day to enable this type of science
to be conducted
the fact that the osl orbit provides 100
percent continuous solar viewing
is also critical to this type of science
and the flexibility it provides greatly
facilitates
the use of tdrs with osl
the solar physics community has an
unprecedented opportunity to conduct
solar
dynamic science on a scale well beyond
anything accomplished to date
or even planned for this century