After half a century the dream of a lifting body spacecraft is returning
Dateline: August 2, 2013, NASA’s Dryden Flight Research Center, the Sierra Nevada Corporation rolled their lifting body spacecraft, the “Dream Chaser,” out of the hangar in preparation for “tow” tests. In the pre-dawn hours this engineering test article was prepared for its first critical workout. What few working on the vehicle probably considered was that they were following in footsteps that had been placed upon the ramp at this same airfield almost exactly 50 years earlier, August 16, 1963; when the chase of the dream of lifting body flight was actually realized.
Lifting body flight had begun as little more than a mental exercise among a few aeronautical engineers. Yet, the practical application of that concept started with a NASA engineer at the Flight Research Center by the name of Dale Reed and a balsawood model of his lifting body concept aircraft. Reed, an R/C model airplane enthusiast, began by tossing his balsawood lifting body into tall grass in order to cushion the landings as he tinkered with the center of gravity on the model. Once he had a good glide established he moved up to towing the model behind one of his powered R/C airplanes and eventually went on to releasing the lifting body into free-flight from the model tow-plane. On one such occasion Reed enlisted his wife to film the operation with an 8mm camera. He later took that film and showed it to his bosses at the Flight ResearchCenter (later named the Dryden Flight Research Center). Backed by a team of like-minded lifting body fans, such as Dick Eldredge and Milt Thompson as well as his 8mm film, Reed gained the quick approval of NASA’s Al Eggers and Paul Bikle to move forward. Soon, by use of some discretionary funding and a lot of after-hours handy work by the staff at the airfield, a full size version of the lifting body was constructed. Called the M2-F1, the lifting body was actually made of plywood and used the landing gear of a Cessna 150 aircraft. On March 1, 1963 it was rolled out to do a series of “tow” tests behind a modified Pontiac car. Fifty years, five months and two days later, another lifting body, the Sierra Nevada Corporation’s Dream Chaser, began its series of tow-tests; only this time the tow vehicle would be a Ford pickup truck.
Along the concrete runway at Dryden the Dream Chaser was systematically towed at speeds of 10, 20, 40 and 60 miles per hour. Data was collected on a wide range of systems including steering, brakes, control surface actuation and landing gear dynamics. Unlike the M2-F1, however, laptop computers and LASER thermometers were among the modern appliances used to evaluate the Dream Chaser on its tow-tests. Additionally, the Dream Chaser was released during its tow-test and allowed to skid to a stop while the vehicle’s aerodynamic speed brakes were tested; as far as the records show the M2-F1 was not released on its first tow-test, but it did fly. Unfortunately, that M2-F1 first flight lasted only a few seconds and only went up a few inches because it was found to be uncontrollable and was quickly landed by test pilot Milt Thompson. Following wind tunnel testing and with its control system re-rigged the M2-F1 was successfully flown on its second tow-test on April 5th, 1963.
Lifting bodies are commonly referred to in terms of being a “shape.” During the development years of the piloted versions there were three basic shapes, the M2, the X-24 and the HL-10. The M2 shape was similar to a half-cone, while the X-24 was similar to an inverted half-cone. The HL-10, however, was more like a rounded arrowhead. All three shapes eventually each flew a protracted series of high altitude super-sonic tests. Over time, the HL-10 shape would be the one to have its name carried into the future. Long after the other lifting-bodies had been placed in museums, the folks at NASA’s Langley Reasearch Center were taking their original HL-10 concept and evolving it into a larger crewed version that they called the HL-20.
First conceived as an emergency crew rescue vehicle and a back-up to the Shuttle, the HL-20 was intended to be used on what was then called Space Station Freedom. The year was 1986 and the HL-20 looked a bit more like a blending of the Soviet BOR-4 test article the X-24A than it did the HL-10. It was conceived to be boosted atop an Evolved Expendable Launch Vehicle, and then glide back to a runway; landing like the Space Shuttle. Unfortunately, the HL-20 was born in the shadow of the Space Shuttle and grew up in the shadow of the Constellation Program, thus it never got beyond the mock-up, artwork and number crunching stage.
Enter the Sierra Nevada Corporation and NASA’s request for competitors to participate in the Commercial Crew Development program. Looking at the HL-20 Sierra Nevada Corporation saw a concept with much of the critical design work already done. From that foundation grew the Dream Chaser. When the time came to down-select three finalists to become NASA’s commercial crew carriers, the Dream Chaser made the cut along with capsule spacecraft from Boeing and SpaceX.
Although the Dream Chaser’s competitors, Boeing and SpaceX have garnered a lot of publicity, the folks at Sierra Nevada Corporation have been working at a grass-roots level with little glamour. They do not have a cult-like following such as that enjoyed by the SpaceX and their Dragon capsule, but they do have the in-the-hangar hands-on engineering style that gave us the M2-F1 and the lifting bodies that led to the Dream Chaser in the first place. By using a touch of Shuttle heritage and a Dale Reed spirit, they have come a long way toward flying US astronauts from US soil and landing them on a US runway once again.
Dream Chaser itself is a highly refined lifting body that takes what was intended for the HL-20 and literally chases that dream toward its intended goal; a true spaceship that can rocket into space and return to earth by elegantly landing on a runway. If they can succeed in making the Dream Chaser fly and actually getting it into space and then returning it to a runway, the folks at Sierra Nevada Corporation will have not only chased, but will have caught the dream of Dale Reed, Dick Eldredge, Milt Thompson and a small army of other lifting body champions. It is a dream that began a half century ago. A dream that was solidified when the M2-F1 made its first free flight on August 16, 1963- exactly 50 years ago today.
AUTHOR'S NOTE: I'm a lifting body "nut" and have been since I was in the 8th grade. From then on I started learning as much as I could about them and messing around with my own "shapes." In high school I developed my own shape and as a part of my 11th grade drafting class project I drew up plans for my lifting body to launch piggyback aboard a sort of Titan IIIC model rocket. It was complete with a pad and a fixed service structure that had a swinging shelter to cover the lifting body. Just by coincidence, that was remarkably close to the Space Shuttle's RSS, even though I had never seen plans or images or even the concept of the RSS at the time. As I worked on the project, my drafting teacher came by and pointed at my lifting body and asked, "What's that?" I told him it was a lifting body- a wingless aircraft. He just walked away shaking his head. When I got my final grade it was a "C" and there was a note scrolled on the page with the lifting body that said, "I thought you would know that an airplane can't fly without wings." Today, my Dr. Zooch Rockets company sells a rocket that uses that exact same shape- and yes, it does fly.
A few years before Dale Reed passed away, my former college roommate, Pete Merlin, who works at NASA Dryden, took one of my lifting bodies in and showed it to him. Mr. Reed approved saying that he thought it would make a good hyper-sonic shape as well. Not bad for a kid who had to teach himself about lifting body flight, eh?