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Astronomical Data Analysis Software and Systems VII
ASP Conference Series, Vol. 145, 1998
R. Albrecht, R. N. Hook and H. A. Bushouse, e
Ц Copyright 1998 Astronomical Society of the Pacific. All rights reserved.
ds.
Hubble Space Telescope Telemetry Access using the
Vision 2000 Control Center System (CCS)
M. Miebach
European Space Agency, Space Telescope Science Institute, 3700 San
Martin Drive, Baltimore, Maryland USA 21218
M. Dolensky
Space Telescope European Coordinating Facility,
KarlSchwarzschildStr. 2, D85748 Garching, Germany
Abstract. Major changes to the Space Telescope Ground Systems are
presently in progress. The main objectives of the reengineering e#ort,
Vision 2000 1 , are to reduce development and operation costs for the
remaining years of Space Telescope's lifetime. Costs are reduced by the
use of commercial o# the shelf (COTS) products wherever possible.
Part of CCS is a Space Telescope Engineering Data Store, the design
of which is based on modern Data Warehouse technology. The purpose of
this data store is to provide a common data source for telemetry data for
all HST subsystems. This data store will become the engineering data
archive and will provide a queryable DB for the user to analyze HST
telemetry. The access to the engineering data in the Data Warehouse is
platformindependent from an o#ce environment using commercial stan
dards (Unix, Windows/NT, Win95). Latest Internet technology is used
to reach the HST community. A WEBbased user interface allows easy
access to the archives.
Some of the capabilities of CCS will be illustrated: sample of real
time data pages and plots of selected historical telemetry points.
1. CCS Architecture
A Web browser with Java support and an account to establish a secure Internet
HTTP connection to the Goddard Space Flight Center (GSFC), is everything
needed in order to use the new Control Center System (CCS). Then full access
to the telemetry of the Hubble Space Telescope (HST) is given (Figure 2). A
public version of CCS 2 is also available.
How does that work? The telemetry data stream of HST is transfered to the
Front End Processor (FEP) via Nascom (Figure 1). FEP provides a communi
cation interface between the vehicle and ground control. It also captures all the
1 http://vision.hst.nasa.gov/
2 http://v2mb20.hst.nasa.gov:4041/demo.html
421

422 Miebach and Dolensky
Web/Data
Server
Oracle
Data
Warehouse
flat
Files
All Points
Archive
Sampled
Telemetry
Client
Various Sources
FEP
Front End
Processor
HST
Nascom HTTP
Process
Middle
ware
Applet
GUI
Browser
.Analysis
.Monitor
.Commanding
....
Figure 1. CCS Archive Architecture
downlinked data and forwards them to the attached All Points Archive. Besides
the All Points Archive there is also the Red Brick Data Warehouse for sampled
data. Without the warehouse the All Points Database containing several ter
abytes of telemetry parameters would be of limited use only. The warehouse
samples data to reduce their size. In this way it is possible to further analyze
them on standard platforms like Pentium PCs. The warehouse also provides
derived engineering parameters and advanced query options. The warehouse is
still under construction, but a Java applet prototype 3 is already available at the
home page of the Science & Engineering Systems Division (SESD) at STScI.
In order to support its heterogeneous clients and DB servers a threetiered
solution was chosen (Mickey, 1997). A Java applet on the client side speaks to
a middleware component on the data server. The middleware then takes care of
the DB access. Rifkin (1997) gives a more comprehensive description.
2. Applications
CCS's main task is not scientific data reduction. Nonetheless, it provides the
means to develop e.g., new calibration algorithms. This is possible, because for
the first time, one can have access to all engineering parameters via the Internet.
So far, only a very limited subset of telemetry parameters is available through
3 http://www.sesd.stsci.edu/

Hubble Space Telescope Telemetry Access 423
Figure 2. CCS Archive Query Form (l.) and RealTime Data Page (r.)
Geomagnetic F ield along HST Trajectory
4 ,0 E 05
2 ,0 E 05
0 ,0 E+00
2 ,0 E 05
4 ,0 E 05
19 .8 .97 22 :53 20 .8 .97 0 :05 20 .8 .97 1 :17 20 .8 .97 2 :29 20 .8 .97 3 :41
Magnetic
Field
[Tesla]
Q598 QDV10MF0 10sec Magne tic F e ld 1 Q599 QDV10MF1 10sec M agne tic F e ld 2
Q600 QDV10MF2 10sec Magne tic F e ld 3
Figure 3. Geom. Field (3 Components) over a Period of 3 Orbits
observation log files. One possible application is mentioned here to illustrate
this.
The Faint Object Spectrometer (FOS) of the Hubble Telescope is an instru
ment that was replaced during the 2nd Shuttle Servicing Mission in February
97. As part of the final archive for this instrument, STECF would like to apply
an improved model of the geomagnetic field to the calibration pipeline. The
required magnetometer readings from the onboard sensors are not part of the
observation log files, but CCS could now provide the missing values. Figure 3

424 Miebach and Dolensky
shows these magnetometer readings for a 5hourperiod, which equals roughly
three HST orbits.
3. Outlook
CCS will become operational in April 98. At this point it will provide all the
functionality required for the 3rd Shuttle Servicing Mission in 1999. By the
end of 1999 the data warehouse will be fully populated, i.e., it will contain the
telemetry back to launch in 1990.
Acknowledgments. Many thanks to Je# Johnson (Lockheed Martin) and
Doug Spiegel (NASA) who never got tired answering questions and spent a lot
of time on user support for CCS.
References
Rifkin, A. 1997, Reengineering the Hubble Space Telescope Control Center Sys
tem, Institute of Electrical and Electronics Engineers Inc.
Mickey, S. 1997, Internet Java & ActiveX Advisor, Advisor Publications Inc.,
Vol. 4/94, p. 1621