unflown

10

     Rarely does a single aircraft change our daily lives as much as NASA 802 has. This aircraft, a modified F-8C Crusader, may look like a standard model from the outside. But inside, it is heavily modified. In the late 1960s, NASA Dryden Flight Research Center (now Armstrong) set out to create a safer, lighter and easier to maintain jet airplane by removing heavy, battle-damage prone mechanical flight control linkages, replacing them with digital flight control system with better redundancy. In this system, control inputs are routed to a computer. Then, the computer tells the control surfaces to move based on the pilot’s controls. Almost every jet aircraft and transport aircraft manufactured today uses this technology. If you’ve flown aboard an airliner, chances are, your life depended upon the research that this F-8 performed. This system changed the face of not only aviation, but our everyday lives. Unless you’re into vintage automobiles, the car that you own uses this technology to transmit your accelerator inputs to the engine. Some new cars use a complete drive-by-wire system with no mechanical linkages for steering.

     We’ve established that this F-8 used a computer for control. But it didn’t use just any computer. At the time, the only machine up to the task of performing real time computations with 100% reliability was the Apollo Guidance Computer which was installed in the gun bay of the aircraft. But this wasn’t just any Apollo Guidance Computer. This F-8 flew with a computer than had just returned from the moon. Apollo 15 hardware was used in this aircraft. The final photo in the set shows the actual Apollo Guidance Computer Display and Keyboard (DSKY) that flew on Apollo 15 and was later installed in this F-8 aircraft. Initially, this F-8 flew with unflown backup computer hardware, but after this component malfunctioned, Dryden lobbied to NASA headquarters for a replacement. It took some convincing, but they were eventually allocated the computer that flew on Apollo 15.

     NASA Dryden test pilot Gary E. Krier first flew this F-8 on May 25, 1972. Many were skeptical, but the aircraft performed flawlessly. Later, the Apollo hardware would be replaced with an improved, purpose-build computer. NASA 802 also went on to explore pilot induced oscillation suppression. This test program lasted for 13 years, completing its final flight on April 2, 1985. Digital fly-by-wire technology went on to fly with the Space Shuttle. The first operational fighter jet to use this technology was the F-16. Refinement of this system paved the way for later developments like Intelligent Flight Control, Auto Collision Avoidance, and Self-Repairing Flight Control systems, all thanks to NASA 802 and the people behind the Digital Fly-By-Wire research program.

9

     Every rocket has a payload; even the small, solid fuel rocket that I built and fired while attending Space Camp as a child. My rocket launched an earthworm as its payload, carrying it about 1,000 feet above the ground. A parachute opened and brought my payload it back to the ground, alive and unscathed. Obviously, larger rockets tend to carry larger payloads. The Saturn V Moon rocket was the largest launch vehicle ever successfully flown. The whole point of the Saturn V was to lift this, the Lunar Stack, off of Earth, insert it into a brief period of Earth orbit, then push it toward the Moon.

     The Lunar Stack consisted of several systems. The very tip of the rocket is a component called the Launch Escape System. This was a tower fixed to the nose of the manned capsule during launch, which contained a solid rocket motor that would be fired if the rocket started to break up, pulling the crew to safety. Luckily, this never had to happen in the Apollo program. If everything was performing nominally, the Launch Escape System would be jettisoned away from the capsule after ignition of the S-II second stage.

     The next major system down the line is the Command-Service Module (CSM). This two-part component consists of the Command Module (CM) and the Service Module (SM). The CM carried all three astronauts during the whole flight, from launch, all the way to splash-down, excluding the time when two of the three astronauts would transfer to the Lunar Module (LM) for their excursion to the moon. The particular Command-Service Module pictured here is called CSM-115, which was manufactured for the cancelled Apollo 19 mission. It is only partially completed. Normally, the unflown Command Modules are a shiny silver color, but this module sat outside for decades, and has taken the appearance of one that has suffered an entry into the atmosphere. 

     The conical structure aft of the CSM is the Spacecraft-Lunar Adapter, which housed and protected the Lunar Module (LM), and the CSM engine during launch. Once the Lunar Stack was on a path to the moon, the CSM would detach from the SLA cone, which would open up like flower petals, exposing the LM. The CSM would turn 180°, dock with the LM, and pull it away from the S-IVB third stage. Then, the CSM and LM would continue their path to the Moon, separate from the S-IVB third stage.

     Each small component of the Apollo System, from the launch, to the Escape Tower, and everything in between, is incredible to me. I could go into endless detail about each small component within these systems, but that will have to wait for future articles.