The Spitzer Science Center (SSC) Software Science Operations System (SOS) is a large, complex software system.
Over 1.2 million lines of code had been written for the SOS by time of launch (August 2003). The SSC uses a defect
tracking tool called GNATS to enter defect reports and change requests. GNATS has been useful beyond just tracking
defects to closure. Prior to launch a number of charts and graphs were generated using metrics collected from GNATS.
These reports demonstrated trends and snapshots of the state of the SOS and enabled the SSC to better identify risks to
the SOS and focus testing efforts. This paper will focus primarily on the time period of Spitzer's launch and In Orbit
Checkout. It will discuss the metrics collected, the analyses done, the format the analyses was presented in, and lessons
learned. This work was performed at the California Institute of Technology under contract to the National Aeronautics
and Space Administration.
The primary scheduling requirement for the Spitzer Space Telescope has been to maximize observing efficiency while
assuring spacecraft health and safety and meeting all observer- and project-imposed constraints. Scheduling drivers
include adhering to the given Deep Space Network (DSN) allocations for all spacecraft communications, managing data
volumes so the on-board data storage capacity is not exceeded, scheduling faint and bright objects so latent images do
not damage observations, meeting sometimes difficult observational constraints, and maintaining the appropriate
operational balance among the three instruments. The remaining flexibility is limited largely to the selection of
unconstrained observations and optimizing slews. In a few cases, the project has succeeded in negotiating DSN tracks to
accommodate very long observations of transiting planets (up to 52 hours to date with even longer requests anticipated).
Observational efficiency has been excellent with approximately 7000 hours of executed science observations per year.
Performance goals for data archive systems need to be established early in the design process to ensure stability and
acceptable response throughput. Load testing is one technique used to measure the progress towards these performance
goals. Providing resources for load-test planning is critical, and this planning must include feasibility studies, tool
analyses, and generation of an overall load-test strategy. This strategy is much different for science data archives than
other systems, including commercial websites and high-volume data centers. This paper will provide an overview of the
load testing performed on the Spitzer Space Telescope's science archive, which is part of Science Operations System at
the Spitzer Science Center (SSC). Methods used for planning and conducting SSC load tests will be presented, and
advanced load-testing techniques will be provided to address runtime issues and enhance verification results. This work
was performed at the California Institute of Technology under contract to the National Aeronautics and Space
Administration.
The Spitzer Space Telescope, the fourth and final of NASA's Great Observatories, was launched in August 2003. It has been a major scientific and engineering success, performing science observations at wavelengths ranging from 3.6 to 160 microns, and operating at present with a roughly 92% science duty cycle. This paper describes the essential role and procedures of the Spitzer Observatory Planning and Scheduling Team (OPST) in providing rapid rebuilds of sequences to enable the scheduling of Targets of Opportunity and to recover from anomalies. These procedures have allowed schedulers to reduce the nominal lead time for science inputs from six weeks to 2 or 3 days. We discuss procedures for modifications to sequences both before and after radiation to the spacecraft and lessons learned from their implementation.
KEYWORDS: Databases, Space operations, Data archive systems, Observatories, Data processing, Space telescopes, Calibration, Infrared cameras, Telescopes, Infrared imaging
The Spitzer Space Telescope was successfully launched on August 25th, 2003. After a 98 day In Orbit Checkout and
Science Verification period, Spitzer began its five and one half year mission of science observations at wavelengths
ranging from 3.6 to 160 microns. Results from the first two years of operations show the observatory performing
exceedingly well, meeting or surpassing performance requirements in all areas. The California Institute of Technology
is the home for the Spitzer Science Center (SSC). The SSC is responsible for selecting observing proposals, providing
technical support to the science community, performing mission planning and science observation scheduling,
instrument calibration and performance monitoring during operations, and production of archival quality data products.
This paper will provide an overview of the Science Operations System at the SSC focusing on lessons learned during
the first two years of science operations and the changes made in the system as a result. This work was performed at the
California Institute of Technology under contract to the National Aeronautics and Space Administration.
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