NASA’s NuSTAR mission, or Nuclear Spectroscopic Telescope Array, was launched June 13, 2012 via an Orbital Sciences Corp. Pegasus XL rocket. While the X-ray observatories mission is interesting in itself, my main interest is in the Pegasus. It is unique among launch systems today in that it is air-launched, from the belly of a modified Lockheed L-1011 airliner. It is a concept that Stratolaunch Systems plans to take a much, much larger platform.
Pegasus, which has been around since 1990, basically uses the L-1011 as its zeroth stage. The airliner carries it to around 40,000 feet before it is dropped and the first stage ignites. It initially climbs under a combination of rocket power and aerodynamic lift from the wings which are part of the first stage, until the second and third stages complete the flight as pure rockets. All three stages use solid propellant. The launch of a Pegasus looks more like an old X-plane launch, like an X-15 – and indeed the initial Pegasus flights used the same modified B-52 carriers, until the L-1011 took over.
This launch highlight video is slightly disappointing. It was a night launch and I’m sure the ignition of the Pegasus must’ve been spectacular, but there is no footage from any chase aircraft. So we never actually get to see the rockets fire. But the interesting part, for me, starts around the 1:40 mark, when the L-1011 begins to taxi and we get a good look at the Pegasus mounted on its belly.
This video gives us a look at the vehicle processing flow in preparation for the launch. We get a look at the Pegasus XL being built up and the payload being mounted, but I think the most interesting part comes at the 5:00 mark when we get to observe the process of mounting the Pegasus to the L-1011 Stargazer carrier.