Identifying Satellite Launch Origins with Historical Examples Michael E. Stringer Bob Teets Robin Thurston ξ

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1 INTRODUCTION Identifying Satellite Launch Origins with Historical Examples Michael E. Stringer Bob Teets Robin Thurston ξ The 1 st Command and Control Squadron s (1 CACS) mission is to maintain the most accurate satellite catalog of Earth orbiting objects. In order for 1 CACS to catalog an object in the space catalog the launch origins of the satellite must be known. If a satellite is launched and there is just one active payload on the launch vehicle and a simple rocket body, then determining which is the payload and which is the rocket body can be easy. However, when a new object is tracked and does not immediately correlate to a known launch, a new analyst satellite is created. An analyst satellite is an object that has not yet been cataloged. The launch origin may not be known and therefore no international designator is assigned. An analyst satellite may be tracked and lost or tracked for months to years before its origin is determined-if ever. When an analyst satellite is lost, the historical element sets (elsets) are kept on file for future correlation efforts. This paper will describe the tools and techniques that 1 CACS uses to identify a satellite s origin so that the object can be cataloged. The 1 st Command and Control Squadron (1 CACS) has the mission to maintain the most accurate and current satellite catalog as possible. 1 CACS was established in 1989 and shortly thereafter the analysts realized that the mission system was slow to upgrade and the mission support system called Correlation, Analysis and Verification of Ephemerides Network (CAVENet) was created. This system allows the analysts to plot the historical trends of satellite element sets (elsets) very quickly and easily. This ability to plot historical elsets allows the analysts to be able to rapidly verify that a new elset correlates with the trend of the object in question and is therefore correct. The tools and databases used by 1 CACS are described by Stringer 1. These tools and databases allow 1 CACS to be able to correlate historical elset data back to the launch so that an analyst satellite or group of analyst satellites, whose launch origins are unknown, can be identified and cataloged. A few examples will be covered that will show long lost objects, breakups, and cross-tags. These examples will show how 1 CACS can identify and fix problems in the satellite catalog (SATCAT). CORRELATING OBJECTS The process of correlating objects starts with searching the catalog file for any satellites that may match the object of interest. Candidate objects for correlation can be Chief Analyst, 1 CACS/DOUA, Space Analysis Center Sencom Contractor, Retired Capt USAF 1CACS ξ Historical Analyst, 1 CACS/DOUA, Space Analysis Center, Retired Master Sergeant, USAF 1 CACS 1

2 found by using the scat program and searching for specific parameters that the analyst is trying to match. Another method would be to use the UNIX grep command to search the catalog files for possible matches. Once possible matches are found the objects can be plotted together for the analyst to verify that the objects correlate. The first parameters checked are usually the right ascension of the ascending node and inclination. If any objects match in inclination and trend the same in node then the objects are in the same plane as the object of interest. The next parameter checked is period to see if any objects trend in period with the object of interest. The next parameter to check is the eccentricity which will indicate if the candidate objects orbital shape match the object of interest. The final step is to verify with any other parameters to confirm that a match or matches have been found. The above process is complete for all near earth object (periods less then 225 minutes) and most deep space objects. However, for near synchronous objects the analyst may start with mean longitude to check for objects that are at the longitude of interest. GOBS 1 can also be used to find objects that match the parameters of plane, relative energy, and longitude. Then the analyst can plot the candidate objects and check the synch plot options to see how well the objects match. The analysts can then look at the longitude plot, longitude drift rate plot, and the relative energy plots individually for a more detailed analysis. CORRELATING UCTS The process for correlating UnCorrelated Tracks (UCTs) is similar to that described above except the UCT files are separated by inclination and year. Therefore if an analyst wanted to search for UCTs on an object with an inclination of 7.0 degrees and wanted to look for possible matches in 1999 then the analyst would plot the file with the object of interest. The UCT files are setup where the first two digits 99 represent that these are UCTs and the next three digits are for the inclination of the UCTs and the last two digits are for the year of the data. The analyst can also plot the UCT files with the candidate objects and the object of interest. This allows the analyst to see all possible matches to the object of interest at the same time and therefore, UCTs may fill in any gaps in data that are not filled in by the candidate objects. COBE DEBRIS EXAMPLE The Cosmic Background Explorer (COBE) satellite was launched on 18, Nov In early 1993, debris pieces were noted to be originating from the COBE payload. There was some question as to whether the satellite was breaking up and NASA was notified. NASA reported that the health of the satellite as intact leading to a theory that the thermal blanket on the satellite was shedding. To date 78 trackable debris pieces have been shed from COBE. Figure 1 is a plot of (COBE) and eight of the 78 pieces of shed thermal blanket. Figure 2 is a plot of period only and enlarged in so the epochs are from 1993 to An analyst can see the different pieces coming off of the payload and by looking at this parameter as well as others the analyst can keep the pieces from getting cross tagged. 2

3 It is fairly easy to tell these eight apart however it can be very difficult to keep the pieces from becoming cross-tagged when there are 78 pieces or in other breakups where there are hundreds of pieces. Currently all but three pieces of debris have decayed that were associated with the COBE payload. Figure 3 shows COBE and the three pieces of debris still in orbit. The first two pieces and are not thermal blanket pieces but are initial deployment related pieces. BREAKUP EXAMPLE Figure 1 Default plot of COBE and eight of its debris pieces. In the last few years CAVENet has been populated with historical observation data and this observation data has many single track UCTs. These UCTs have been processed into single-track elsets and stored in the UCT files as described earlier. These UCT files have lead to the discovery of breakups that had previously gone undetected. Twelve breakups have been discovered using the UCT files and are listed in Table1. SATNO International Desg Common Name Breakup Date A OV2-3/TITAN 3C 21 Dec B ARIANE 1 R/B 27 Feb B ARIANE 1 R/B 04 Jul C ARIANE 3 R/B 18 Sep B ARIANE 2 R/B 22 Dec B ARIANE 2 R/B 19 Apr 89 3

4 G SL-12 R/B (AUX) 26 Jul C IUS R/B(1) 02 Aug B CZ-3 R/B 17 May B ATLAS 75E R/B 29 Jan B ATLAS 2AS CEN 23 Feb 98?? E SL-12 R/B (AUX) 29 Feb 00 Table 1 Breakups discovered by historical UCT analysis. Figure 2 Period plot of COBE and eight of its debris pieces. Figure 4 shows objects and plotted with the UCT file The UCT file was pieced together from the UCT files , , and These files were analyzed and all the UCTs that matched the two breakups were pulled out of their normal UCT files and the specific UCT file was created. Figure 5 is a plot of right ascension of the ascending node for objects and with UCTs Where the UCTs converge on the main satno s plot is where the breakup occurred. 4

5 Figure 3 Plot of COBE and the three debris pieces from it, still in orbit. Figure 4 Breakup plot for objects and

6 Figure 5 Right ascension plot for the breakup of and LONG LOST DELETED EXAMPLE The Syncom 3 rocket body was cataloged but lost immediately after the launch. Sometime after losing the rocket body the object was deleted in an effort to reduce the lost list for long lost objects that were thought to be unrecoverable, this practice is no longer used. However with the CAVENet system and the historical elsets the Syncom 3 rocket body was recovered. Figure 6 shows that the rocket body was tracked as twelve different analyst satellites (analsats) and also as UCTs. In 1993 analsat was matched with This produced a history that went back to This history was then matched back to and 88249, which gave a history from 1988 to This extended history was then searched back to find 56167, 87783, and 87423, which pushed the history back to A very short analsat history, was then matched and a few UCTs were matched from Analsat was then matched to take the history back to With more searching the final analsats, and were matched taking the history back to No further matches could be found at this time. 6

7 Figure 6 Plot of the analsats that form the Syncom 3 R/B history. The next step was to figure out what this object was that kept getting tracked but was not cataloged or had not been correlated to a launch. The databases were searched for candidates that were not tracked or other objects that might have similar orbits to this object. Once candidates were found the analyst would plot these objects together to see if they were a match or were related. Since the object had no further matches, the analyst looked for related objects and found that this unknown object matched the Syncom 3 launch. The analyst also noted that the rocket body from the Syncom 3 launch had been cataloged but was then deleted and that this object must be the deleted rocket body. The Space Surveillance Network (SSN) was tasked to collect signature data on the object and it was confirmed as a rocket body. MIS-CATALOGED OBJECTS Occasionally objects get mis-cataloged from the beginning. The following is an example of one of these mis-catalogs and how it was found and fixed. Figure 7 shows the plot of 02353, which has an international designator (IDES) of (TRANSIT 10), and six other objects from the TRANSIT 10 launch. The plot shows that does not match the rest of the objects from the launch in right ascension of the ascending node (RANODE). This indicates that is incorrectly cataloged to the TRANSIT 10 launch. The parameters for the beginning of the history for object were searched and the TRANSIT 12 launch (IDES ) was a possible match. Figure 8 shows plotted with the objects from the launch of (TRANSIT 12). Analyzing the 7

8 RANODE plot and confirming with the other parameters, matches the launch of TRANSIT 12. Object s common name and international designator were changed to TRANSIT 12 DEB and respectively. CROSS TAGGED OBJECTS Objects get cross-tagged meaning that they are really the opposite tag of each other. An example is YAMAL 101 (25896) and YAMAL 102 (25897). They originally started off tagged correctly and then 27 days after launch, as both were drifting to their synchronous locations, they were swapped. Figure 9 shows the history of these two objects and shows that the objects were cross-tagged on day. Recently while checking NASA s Space Warn Bulletin an analyst noticed that YAMAL 101 was said to be having problems and that YAMAL 102 was on station. Also a commercial broadcasting web site that lists the locations of commercial satellites indicates that YAMAL 102 is stationary at 90 degrees east. Looking back at the history showed that the cross-tag occurred, so on the objects were swapped back to their proper tags. YAMAL 101 is inoperative and did not stop at its planned location of 45 degree east and YAMAL 102 is active and stationary at 90 degrees east. Figure 7 Plot of 2353 with incorrect cataloged launch. 8

9 Figure 8 Plot of 2353 with correct cataloged launch. Figure 9 Cross tagged YAMAL 101 and YAMAL

10 SUMMARY The historical data on the CAVENet system allows for identification of improperly cataloged objects. The reasons for the errors are varied as demonstrated by the examples used throughout the paper. The examples are by no means the only possible errors that can be in the satellite catalog but are used to show the possible problems and the methods for fixing these errors. Nearly 200 objects have been recovered to date. The term recovered means that the object has been updated to be correctly cataloged, updated so that the elset is current, or correctly decayed. The cumulative sum total of time that these objects have been lost or mis-cataloged is over 2000 years. 1 CACS continues to analyze this historical data to make the satellite catalog as accurate as possible. 1 CACS also continues to develop methods to accurately catalog and maintain all objects from launch until decay. 1 Stringer, M. E., Teets, R., Tools and Databases used to Maintain the Space Catalog at 1 CACS, Presented at the Fourth US/Russian Space Surveillance Workshop, US Naval Observatory, Washington DC, Oct 23-27,