[JSR 501] The Mission Profile of USAF Program 827 (CANYON) ------------------------------------------------ As part of an effort to improve the list of objects in the geostationary altitude regime (of interest due to orbital debris concerns), I have been taking another look at what is known of the CANYON communications intelligence satellite program. CANYON was the first geosynchronous signals intelligence satellite, launched from 1968 to 1977 as part of NRO's Program A and developed by the US Air Force. The program was highly classified (and remains so even over 20 years after program completion) and for many years analysts thought they were a first-generation DSP early warning satellite. Launches under the Program 827 designation were carried out by the uprated Atlas SLV-3A/Agena D rocket from Cape Canaveral. CANYON's successors have flown under the designations CHALET, VORTEX and MERCURY; official statements following the last MERCURY launch failure imply that despite these code name changes, and several spacecraft block changes, these satellites are all considered part of a single geostationary communications intelligence program. It is conjectured that the CANYON spacecraft features a cylindrical bus of order 1.5m in diameter attached to one or more large antennas; it is thought to have transmitted its data to a ground station at Bad Aibling in Germany. I will not speculate on the detailed mission or capabilities of the spacecraft, although it is not a huge leap to assume the synchronous orbits were mostly stationed at longitudes allowing surveillance of the USSR and China. There were seven CANYON launches, as follows: Satellite Launch vehicle S/N Pad Launch Date CANYON 1 AFP-827 F1 (7501) Atlas Agena D (5501A) CC LC13 1968 Aug 6 CANYON 2 AFP-827 F2 (7502) Atlas Agena D (5502A) CC LC13 1969 Apr 12 CANYON 3 AFP-827 F3 (7503) Atlas Agena D (5203A) CC LC13 1970 Sep 1 CANYON 4 AFP-827 F4 (7504) Atlas Agena D (5503A) CC LC13 1971 Dec 4 CANYON 5 AFP-827 F5 (7505) Atlas Agena D (5204A) CC LC13 1972 Dec 20 CANYON 6 AFP-827 F6 (7506) Atlas Agena D (5506A) CC LC13 1975 Jun 18 CANYON 7 AFP-827 F7 (7507) Atlas Agena D (5507A) CC LC13 1977 May 23 (There is some confusion about the last launch; it is just possible that the 1977 May 23 launch is an AFP-472 Aquacade and that CANYON 7 was the launch of 1977 Dec 11, although photographs of the launch shroud tend to support the list given here). CANYON 4 was lost in a launch failure. There are several sources of data giving clues as to the operational profile of the other CANYON missions: 1) Orbital data provided to the United Nations - this is patchy and sometimes erroneous. (Note: at best, the UN data gives only orbit height and inclination, not a full TLE set which would allow determination of the satellite's position). 2) Orbital data published by the Royal Aircraft Establishment. 3) Entries (without orbital data) in the Space Command satellite catalog. 4) A comment in Aerospace Daily, 1969 Nov 6, cited in a letter by Geoff Richards to Spaceflight (37.316) in 1995, indicated that two Agenas "had performed the coast to geosynchronous orbit, where they were providing power and attitude control to their payloads". (I'd love a fax of the page from Aerospace Daily if anyone has it) First let us review the UN data. CANYON 1,2,3, 5, and 6 are given consistent data: ID Period Peri Apo Inc 1968-63A 1436.0 31680 x 39862 x 9.9 1969-36A 1436.0 32672 x 39251 x 10.2 1970-69A 1441.9 31947 x 39855 x 10.3 1972-101A 1440.4 31012 x 40728 x 9.7 1975-55A 1422.0 30200 x 40800 x 9.0 These distinctive orbits are near-geosynchronous but elliptical and inclined, and seem to be a fingerprint of the CANYON program (and possibly some of its successors). No geosynchronous orbit is given for CANYON 7: 1977-38A 739.0 191 x 40980 x 27.1 is a plausible transfer orbit; around this time the US began the practice of only giving transfer orbit data for many classified satellites, even if the satellite was only in that orbit very briefly. However, an extra object was cataloged with this launch, 1977-38C: 1977-38C 1440.0 34325 x 34500 x 0.3 This is a bit worrying, since the orbit is much more circular than the CANYON payloads - it makes me a bit concerned that 1977-38 might not be a CANYON, but only a bit since my confidence in the UN data's reliability is low. The alternate possible launch, 1978-38A, has a lower transfer orbit apogee with no final orbit given, and doesn't seem as likely. The most interesting piece of data is the orbit given for 1975-55B, the Agena rocket stage for CANYON 6: 1975-55B 1416.0 29700 x 40400 x 8.0 This orbit is similar to the payload, but indicates some small maneuver to separate from it. What about the other Agena stages? The final stages for CANYON 1, 2 and 3 were never cataloged - until May 2003! No orbital data were released, so all we can deduce from this is that in 2003 the Agenas from these launches were believed to be still in orbit and separate from their payloads. CANYON 5's Agena was cataloged at the time of launch and an orbit identical to the payload was given to the UN. Sometimes for classified launches the US gives the same orbit for each piece of a launch whether or not those individual pieces were ever in that orbit, so I don't think this is definitive proof that the CANYON 5 Agena was in a 1440 minute orbit - but it is suggestive. CANYON 7's Agena is given the same transfer orbit as its payload. The RAE gives 'Orbit similar to 1970-46B' (a RHYOLITE Agena in GTO) for 1970-69B; clearly this is a guess and should be discounted. For 1972-101B, they give a 200 x 33370 km x 28.12 deg orbit marked 'approximate', probably also a guess. For 1975-55B they give the UN orbit but misidentify the launch as a Titan. For 1977-38 they give 'approximate' orbits which may also be discounted. In general, it appears the RAE did not have access to any data beyond the UN filings. What can we conclude? I present three scenarios. In all cases, we can assume that the Agena performed an insertion burn to low parking orbit with an inclination of 28 degrees, followed by a second burn to geostationary transfer orbit and coast to geostationary altitude. Scenario 1: The Agena separated after the GTO burn and the payload coasted separately to apogee, then used a solid kick motor (possibly an Aerojet SVM-3, which is thought to have been used for a classified program) to enter the operational orbit. In favor of this scenario is that no other Agenas ever made an apogee burn (although they are certainly capable of it); it's the most obvious scenario in the absence of other data, and it's the guess that the RAE made. Against this scenario is the orbit given for 1975-55B, and the comments in Aerospace Daily, Scenario 2: For the first three missions, the Agena made the apogee burn and remained attached to the payload throughout its lifetime and thereafter. For later missions, the payload gained weight and Scenario 1 was followed. In favor of this scenario, the failure to catalog (until now) the Agena rockets for the first three flights made it seem that they were different, and that there was no separate Agena. This would be a natural evolution from other contemporary classified Agena missions (e.g. MIDAS-RTS) in which the Agena provided a spacecraft bus for extended duration missions. This scenario seemed the most plausible until the recent cataloging of the missing Agenas. However, it is just possible that this is an administrative cataloging in a misguided attempt to clean up the books, with no actual tracking data and an unverified assumption by Space Command that the Agenas did separate. Furthermore, identifying tracked objects as associated with a particular launch after a 30-year period is challenging. Therefore, I now regard Scenario 2 as much less likely but not entirely ruled out. Scenario 3: The Agena made the apogee burn. For the first three missions, it may have remained attached to the spacecraft during operational lifetime to provide attitude control, while the spacecraft's own 3-axis stabilization system was being debugged (This approach was used with some of the early KH-7 spy satellites) and then separated later in the mission. For later missions, the Agena separation happened right after the apogee burn. The payload had small thrusters to adjust the orbit after Agena separation. The Agenas are left in orbits similar to the one given for 1975-55B. Scenario 3 seems to best fit the available data. Reviewing the data, it seems clear that there is no convincing evidence that any of the CANYON Agenas remained in geostationary transfer orbit. I therefore conclude that the empty Agena D rocket stages from the CANYON launches are all separate satellites in orbits of 1410-1450 minute period with original inclinations of around 10 degrees, and typically 31000 x 40000 km x 10 deg. I therefore plan to add these Agenas to my catalog of orbits in the geosynchronous band. I welcome comments on this analysis, with extra credit for anyone who can identify what debris object 1977-38C might be.