It is a tradition for me to splurge on a bunch of books that arrive just in time for when I have a break, so in keeping with this tradition I ordered a veritable array just in time for the conclusion of my summer internship at Microsoft and my statics class. Among the pile now sitting at the base of my desk are these two books: Spaceflight Dynamics by William E. Wiesel and Control Systems Engineering by Norman S. Nise. Both of which immediately captivated me with their covers, as they both featured this oddly pyramidal rocket, that seemed to be a single stage and also looked like nothing else I had ever seen before. It was also interesting, as they appeared on two textbooks whose topics imply this vehicle was doing some very important and challenging things.
So, I took to Google to try to figure out what it was. I tried a lot of different searches, ranging from ‘NASA triangle rocket’ to ‘NASA concept reusable rocket’ and many more variations on the shape and purpose, but all I got was radio silence. It was like I was experiencing communications blackout in a re-entering Mercury capsule. I then tried googling the specific contents of the covers, and still no dice. I began reading Spaceflight Dynamics, scanning for any indication of what this mysterious machine was, but to no avail. As I’m writing this, I curiously checked the inside cover for Control Systems Engineering and it says exactly what it is and where the photos are from, which is slightly embarrassing for me, but my impatience and a circuitous route make for a better story.
After an arduous (5 minutes) amount of time poking around on the internet, I finally figured out what it was: the McDonnell Douglas DC-X. It was one of the first VTVL (vertical takeoff, vertical landing) rockets to be brought to life in the early nineties and was intended to be a reusable single-stage-to-orbit rocket that was devised by McDonnell Douglass in partnership with the DoD’s Strategic Defense Initiative Organization (SDIO). It later on fizzled out at SDIO and got passed on to NASA. The interesting part is that these two book covers actually tell a bit of this story. The image on the left for Control Systems Engineering is actually a composition of real images taken at a test launch at White Sands, New Mexico, when the project was still under SDIO. The image on Spaceflight Dynamics however clearly sports the NASA logo, and actually shows the DC-XA, with the ‘A’ standing for advanced, based on the changes in design NASA made.
Douglas SASSTO
DC stands for nothing more than ‘Delta Clipper’ according to Google, and is supposed to pay homage to the McDonnell Douglas line of famous airliners. The whole thing just looks fantastically futuristic, and I must say I am a big fan of the design. In researching this vehicle I also found out about the Douglass SASSTO (Saturn Application Single Stage to Orbit) launch system from 1967 which is also just bananas. The more amazing part is how some variations of the SASSTO look similar to New Shepard, or to Virgin Galactic’s SpaceShipTwo today.
But, back to the DC-X. Thanks to YouTube, I was able to find the video of the flight that is actually on the cover of Control Systems Engineering. It’s given below, and I think you’ll find it really neat since it was so long ago. It’s especially neat given how Blue Origin and SpaceX have grown so much in the past decade as offering reusable systems. Speaking of which, it turns out when this program was scrapped by NASA, a lot of the engineers went to work for Blue Origin, and that a fair bit of the design of the DC-X inspired New Shepard. I think this is quite apparent in the landing legs myself.
Something else interesting about the DC-X is that it didn’t perform a flip maneuver - that is, it was planned to re-enter the atmosphere with it’s aft side down; hence why it had a head shield on the bottom of its pyramidal shape. This does however make sense because it has a large surface area so thus is can displace lots of heat, and it means less maneuvering, but it was different from the consensus at the time which is interesting.
The final neat couple of facts I’ll leave with you are that the eye-catching pyramidal shell was custom made by Scaled Composites (it all makes sense now), and that it used 4 Pratt and Whitney engines (according to Control Systems Engineering). A rather interesting part to all of this is that other sources say that is used 4 RL-10 engines which are made by Aerojet Rocketdyne. If anyone knows what it actually used, I would love to hear about it. Wikipedia, funnily enough, describes the rocket as being made from ‘off the shelf parts’. I’ll be quite happy just as soon as I can find on which shelves these parts can be found. Finally, it flew a total of 12 times, had some cute little control surfaces, and Pete Conrad was even present at some of the launches in New Mexico.