Continuing Kepler's Quest Assessing Air Force Space Command's Astrodynamics Standards (2012) / Chapter Skim
Currently Skimming:
1 Meeting the Mission
1 Meeting the Mission
Pages 7-18
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 7... ...
The problem is further exacerbated by interactions between sensor data and object dynamics. This is the challenge that the Air Force faces in using astrodynamics algorithms to maintain a catalog of Earth-orbiting space objects and to provide space situational awareness to its many customers.
|
From page 8... ...
The JSpOC currently uses the algorithms found in AFSPC standardized astrodynamics algorithms for a sig nificant portion of its daily space operations, in which it must detect and track space events and maintain a catalog of more than 20,000 space objects. A typical day at the JSpOC using the standardized astrodynamics algorithms includes: • Collecting and processing 400,000 satellite observations; • Updating at least three times a special perturbations precision catalog on more than 20,000 objects; • Preparing and transmitting 200,000 Space Surveillance Network (SSN)
|
From page 9... ...
Known in the past as the Navy Space Surveillance System, and now as the Air Force Space Surveillance System (AFSSS) , this sensor is a set of bistatic radars consisting of three transmitters and six receiv ers located along a great circle on the 33rd parallel north across the southern United States.
|
From page 10... ...
Either NASA or the universities themselves developed the necessary control and orbit determination software, again tuned to the specific application and type of data. Standardized astrodynamics algorithms were originally developed within Air Force Space Command to pro vide software for the user community to ensure the interoperability of military space surveillance systems with the C2 Space Surveillance Center within the North American Aerospace Defense Command (NORAD)
|
From page 11... ...
Finding: AFSPC has recognized the importance of maintaining interoperability to support the community of operational users. AFSPC standardized astrodynamics algorithms have been implemented in various mainframe-based computer systems at the C2 Space Surveillance Center (renamed the Space Control Center; SCC)
|
From page 12... ...
Products and services can be more loosely coupled in an SOA, making it easier to provide advanced products to some users while still supporting legacy products for those who do not need a change and may have no funds to adapt their organic systems to the advanced products. DESCRIPTION OF THE CURRENT "STANDARDS" The standardized astrodynamics algorithms were originally documented in Air Force Space Command Instruction AFSPCI 60-102, Space Surveillance Astrodynamics Standards, and included standards for coordinate systems and time, physical constants, physical models (e.g., neutral atmospheric density models)
|
From page 13... ...
Software implementations of the astrodynamics algorithms with accompanying test cases are maintained by Air Force Space Command and distributed to authorized users who need to interface with the JSpOC. Besides the goal of interoperability, the standardized astrodynamics algorithms have the goal of reducing cost by eliminating the need for independent software implementations of astrodynamics algorithms and maintaining separate software baselines across multiple space surveillance systems.
|
From page 14... ...
DOD Users During the course of the committee's deliberations it became apparent that it would be difficult to evaluate the performance of standardized astrodynamics algorithms against specific DOD requirements because many requirements were classified and out of the scope of this unclassified effort. In addition, there are multiple Air Force requirements documents with sometimes conflicting accuracy requirements such as the 2000 USSPACECOM Space Control Capstone Requirements Document (CRD)
|
From page 15... ...
Another example of data-induced accuracy variation can be seen in the results obtained for SP orbit predictions for the Topex/Poseidon satellite in a 1340-km circular orbit. The accuracy was improved by a factor of three by increasing the number of tracks from the Space Surveillance Network radars; however, the biggest improvement 100 90 80 70 Position RMS (meters)
|
From page 16... ...
Finding: For satellites not experiencing significant atmospheric drag, the current orbital coverage and quality of the Space Surveillance Network sensor data are more of a limitation on precision orbit accuracy than the standardized astrodynamics SP algorithms. Civilian Government Users Both NASA Houston human spaceflight and NASA Goddard robotics made presentations on their use of JSpOC conjunction products.
|
From page 17... ...
ESA used onboard GPS data while JSpOC used SSN radar data to fit the orbit prior to the prediction. SOURCE: Denise Kaya, A9AC, 1-6b Figure Air Force Space Command, presentation to the Committee for the Assessment of the U.S.
|
From page 18... ...
National Space Policy there is an increased emphasis on sharing of space situational awareness data with mission partners and commercial and foreign entities. New standardized astrodynamics algorithms will be required for the exchange of space situational awareness data.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.