Welcome to This Date in Aviation History, getting of you caught up on milestones, important historical events and people in aviation from March 13 through March 15.
March 15, 1972 – NASA announces the final design of the Space Shuttle. Throughout the manned space program, from Mercury to Gemini to Apollo, all parts of the launch system, from booster rockets to crew capsules, were expendable. But even before the first astronaut set foot on the Moon on July 21, 1969, NASA had already begun thinking about what future space travel would look like. As the space agency imagined the next generation of space vehicles, they considered ways to make at least part of the system reusable. In 1969, President Richard Nixon formed the Space Task Group to investigate and develop a new launch system and vehicle that would be less expensive than previous systems, and one that could be used by NASA, the Department of Defense, and perhaps non-government commercial entities. But the biggest question that needed to be answered was just what form this new spacecraft, dubbed the Integrated Launch and Re-entry Vehicle (ILRV), would take.
From the start, engineers envisioned a two-stage system that had the smaller vehicle, caller the orbiter, sitting atop a larger launch vehicle, called a booster. In its earliest guise, the booster wasn’t just a rocket, but had wings and pilots. The orbiter and booster would have launched vertically and, after the orbiter separated to continue its journey into space, the booster would be piloted back to Earth to be refueled and reused. Like the final Space Shuttle design, the booster would essentially be a flying fuel tank, but both the orbiter and booster were envisioned with air-breathing jet engines to allow controlled flight for landing. However, like so many other aspects of the post-Apollo space effort, economics played a major role, and NASA simply didn’t have the money to pursue such an ambitious system, along with the creation of the orbiting space station that the ILRV was meant to service. The original concept would only lift about 25,000 pounds of payload into orbit, and the US Air Force, whose money was vital to the program, wanted a payload of 65,000 pounds for launching military satellites. NASA had to go back to the drawing board.
Not only did they have to redesign the Shuttle, they had to rethink the entire space station concept. NASA had originally planned for the station to be a large, single unit like Skylab. But changing the concept of the space station to one of modular construction, as we see today in the International Space Station (ISS), allowed NASA to reimagine the Shuttle as a vehicle that would carry those modules into orbit while also providing the payload space the Air Force required. Two basic design concepts then emerged. The first was called parallel burn, where the orbiter’s engine would be ignited at launch and burn in tandem with solid rocket boosters. The second was called series burn, where the orbiter’s engines would not fire until after the booster rockets were finished. Following a careful analysis of the cost of both systems, NASA opted for parallel burn, and announced on March 15, 1972 that the final design would be essentially what we see today: an orbiter attached to a external fuel tank (EFT) and lifted by two solid rocket boosters (SRBs). Of these three elements, the orbiter and the SRBs would be reusable. The SRBs would separate from the fuel tank after their solid fuel was expended and parachute back to Earth to be reused. The orbiter would re-enter Earth’s atmosphere after its mission and glide to a landing. The external fuel tank, which carried liquid hydrogen fuel and liquid oxygen oxidizer to power the orbiter’s main engines, would be expendable, breaking up in the atmosphere before impacting the Indian Ocean.
On July 25, 1972, NASA awarded a contract for development and construction of the Space Shuttle to the International Space Division of Rockwell, as well as management of the overall integration of the vehicle and the launch system. With the general design finalized, the prototype orbiter Enterprise was the first to be built in 1976. Though it never went to space, it was used for critical free-flight testing. Four operational Shuttles, Columbia, Challenger, Discovery, and Atlantis were built, and Columbia made the maiden flight of the Space Shuttle program on April 12, 1981. Two Shuttles, Challenger and Columbia, were lost to accidents, and a fifth operational Shuttle, Endeavour, was built in 1991 to replace Challenger. All told, the five Shuttles completed 133 missions during their 30 years of service, and the Space Shuttle program ended with the final flight of Atlantis on July 21, 2011.
March 13, 1969 – Apollo 9 returns to Earth. A critical rehearsal for the Apollo 11 landing on the Moon, Apollo 9 was launched from Kennedy Space Center on March 3, 1969 as the third manned mission of the Apollo program and spent 10 days in Earth orbit. Apollo 9 marked the first flight of the complete Apollo spacecraft, with both the Command/Service Module (CSM) and Lunar Module (LM) launched atop the Saturn V rocket. During three spacewalks, the crew tested new self-contained spacesuits that would be used on the Moon, and performed docking and flight tests of the LM. The flights of the LM, testing both descent and ascent engines, marked the first flight of a spacecraft that was not designed to return to Earth. Apollo 9 splashed down 160 miles east of the Bahamas, the last time a spacecraft splashed down in the Atlantic Ocean.
March 14, 1947 – The first flight of the Lockheed L-749 Constellation, an improved version of the Lockheed L-649 Constellation and the first of the Constellation series to make regular crossings of the Atlantic Ocean. The “Connie” originally entered service with the US Army Air Forces in WWII, and it became one of the great intercontinental airliners when it entered commercial service after the war. The L-749 provided increased range, plus the addition of jet stack exhaust manifolds that increased speed. Further development yielded the L-749A in 1949, which featured a strengthened fuselage and more robust landing gear. The first L-749 was delivered to Pan Am on April 18, 1947, and ultimately 119 L-749s were produced between 1947-1951 before the introduction of the L-1049 Super Constellation.
March 14, 1927 – Pan American World Airways is founded. Better known as Pan Am, the company was started by the United States government in 1927 as a shell company to counter the German-owned Colombian carrier SCADTA. Under the leadership of Juan Trippe, Pan Am grew rapidly by aggressively buying small airlines and expanding mail and passenger routes in South America. By 1937, Pan Am was providing Sikorsky S-42 seaplane service to Europe, and had started pushing westward from the US to Hawaii and the Far East flying the Boeing 314 Clipper and the pressurized Boeing 307 Stratoliner. Following WWII, Pan Am continued to expand its routes as it entered the jet age, and was the launch customer for both the Boeing 707 and Boeing 747. At its peak in the 1960s, Pan Am carried 6.7 million passengers and served 86 countries on every continent except Antarctica. By the 1970s, the oil crisis led to higher fuel prices and fewer travelers, and Pan Am found themselves in massive amounts of debt. After attempting to acquire domestic airlines and selling off major portions of its assets, the remainder of the company was purchased by Delta Air Lines in 1991 for $1.39 billion.
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