Hello, my name is Tim Donnelly. As a member of the LROC Science Operations Center (SOC) I, along with two others, handle the Downlink duties of the SOC. As Shane Thompson posted earlier, the SOC has two teams - Up-link (UL) and Down-link (DL). UL plans the observation time-line for image acquisition, while DL is responsible for monitoring the LROC instrument health (via real-time and stored telemetry) and data processing (management & processing of all files delivered to the SOC from the Goddard Space Flight Center (GSFC) Mission Operations Center (MOC)). Our two teams constitute the Operations Team to which Ernest Bowman-Cisneros referred in his post last week.
Rather than start at the beginning of SOC data processing, we might ask ourselves "Where does all the LROC data end up?". At the completion of data processing and validation, LROC NAC and WAC images are delivered to the Planetary Data System (PDS). The purpose of the PDS is to ensure long-term archiving and accessibility of NASA mission data. The LROC SOC delivers, at 3 month intervals, NAC and WAC EDR and CDR data products to the PDS. Researchers the world-over and interested persons like yourself have unrestricted access to data within the PDS. ASU serves as a 'Data Node' for the LROC PDS products; released data are available directly from the LROC website (http://lroc.sese.asu.edu/) or from the PDS website (http://pds.jpl.nasa.gov/). The larger LROC team also produces 'derived' products, called RDR products, that are delivered to the PDS.
So, where does the data processing journey begin??...on board the spacecraft, of course, after the image is acquired. Once acquired, images as well as stored telemetry are transmitted to Earth during periodic communication links with a high-bandwidth ground-station (a Ka-Band antenna located in White Sands, NM). The images and stored telemetry are then sent to the LRO MOC at GSFC and later forwarded to the LROC SOC. Over 40 different file types are delivered to the SOC, each having information that is either utilized in planning future image observations or that aids in the processing of already-acquired LROC NAC and WAC images. Each file must be checked (or validated) for naming, contents, and other parametric constraints before the file is cataloged (in a database) and then processed. Once supporting data (temperatures, altitude, power, etc. at the time the image is acquired) is ingested, actual processing of NAC and WAC images can proceed through a series of steps to generate and validate the resulting EDR and CDR products, including updates to the database. Repeat that for the 700+ NAC and WAC images taken every day.
WHEW! Imagine doing all that daily without any automation!
Today, LROC data processing is highly automated. When I came on board almost 4 years ago we were in the throes of developing the software, database, pipelines and procedures needed to efficiently and 'automatically' handle the large volume of data that we now process daily. I had just graduated from ASU's MASGIS (Master of Advanced Studies in Geographical Information Science) program (don't assume youth on my part; I turned 58 before I graduated). While I didn't have a background in planetary science, I had knowledge and skills that were applicable to the challenges facing us, and learned other needed skills as we worked together, getting ready for launch day. I spent time in those early days learning the UNIX OS and tools like sed, awk and 'regular expressions' - all of which would enable data processing in the future. In addition, I studied NASA documentation relating to the LRO/LROC mission - goals, objectives, the various data products that we would receive, planned procedures, and other aspects of the LROC mission. At the same time, having experience with databases, I worked on early drafts of the LROC and Apollo databases.
Some of my more memorable moments back then were discussions with Ernest about the data we would receive from the MOC, the data-products we would create and how we might store and relate them in the database. As Ernest explained to me the intricacies of of the data inter-relationships, I could see that he was clarifying his existing knowledge and concepts as he helped me lay the foundation for my own understanding. At the same time I attended an ASU class, taught by our Principal Investigator (P.I.) Mark Robinson, on the basics of Earth's Moon. Up to that time I was fascinated by the Moon because of the Apollo Missions. Mark's class brought those missions (and the Moon) to life, based on the science Apollo represented and the scientific exploration LROC was just beginning. My introduction to images of the Moon from space came from the newly-scanned Apollo Missions' Metric and Pan images being processed within our research group. Now, I review ~15 lunar images a day acquired by LROC NAC and WAC cameras. Regularly, I'm wowed by the realization that I am the first human to see a particularly powerful image just acquired by a spacecraft orbiting the Moon.
Published by Tim Donnelly on 21 July 2011