While hanging out at Rainbow Canyon awaiting the next jet, someone was flying high above.  They were pulling a contrail at their altitude so you had a really good idea of their flightpath.  They were flying regular extended orbits above us.  The racetracks they left in the sky made it all pretty simple.  A look at an ADS-B tracker told me that this wasn’t a tanker waiting for trade.  It was NASA’s DC-8.  This is a rare beast indeed and, while still a long way off, I was glad to get a shot of some sort of it.