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Apollo Ephemeris Support Data

The original ephemeris data were originally computed and recorded to paper and then later recorded to microfilm. Due to the degradation of the paper copies, some of the records were not converted to microfilm. The National Space Science Data Center (NSSDC) scanned the microfilm records to Tagged Image File Format (TIFF) files, where the state vector data for a single observation sometimes spans several pages. These files were received by Arizona State University (ASU), and a custom Optical Character Recognition (OCR) algorithm converted the raster images to text format for most of the ephemeris scans. Manual methods were implemented to record values that failed OCR conversion. The final values of the OCR conversion, manual efforts, and subsequent validation are stored in the spreadsheets in the table below.

These kernel files should be considered "archival" since we now have much better coordinate information for features on the Moon. The first iteration of these files are in the table below. Please note that these are "first-run" files and new versions will likely be uploaded in the future.

What are state vectors?

For the purpose of the Apollo Flight Film Scanning project, a state vector file consists of one or more pages containing spacecraft and camera position information for a single image frame. As an example, the state vector file for Apollo Metric frame AS15-M-0072 can be found here: AS15-M-0072 state vector. For more detailed information about the state vectors and their reliability, read the "Apollo Photographic Evaluation" data books found in the table of support documents below.

State vector information tells the user the location of a spacecraft in space relative to another body, at a given time. In the case of Apollo, the state vector information is tied to the Metric and Panoramic frames. This allows the position of the Command and Service Modules (relative to the Moon) to be known at the time when an observation was taken. Knowing this information, we can know where on the Moon the image should be.

What data are available?

Currently the data are available in the form of comma-delimited ASCII spreadsheets and SPICE kernel files. We are working to release the original state vector scans in the form of PDF files as new products for the frames and as a combined set of documents for each mission and camera.

How can SPICE files be used?

There are several software suites available that utilize SPICE kernel files.

The NAIF website has several tutorials on what SPICE is and how it can be used, along with several toolkits for using it. So far, there are toolkits for C, IDL, Matlab, and Fortran. A ruby gem wrapper of some NAIF tools can be found on the downloads webpage for lunaserv. ISIS is another software suite that utilizes a combination of its own methods and the NAIF toolkit for processing images with SPICE information. Use the NAIF and ISIS websites and tutorials to become familiar with SPICE and the different ways in which it can be used.

Support Documents

Johnson Space Center Space Exploration Resources Arizona State University, School of Earth and Space Explroation Lunar and Planetary Institue LPI

Comments and suggestions can be mailed to webmaster@ser.asu.edu