Fifty years ago today, Boeing flight tested the first “Jumbo Jet”.

Taller than a six-story building, the 747-100’s 195-foot wingspan was 75 feet wider than Orville Wright’s first flight at Kitty Hawk, NC. Within six months, the first 747 delivered to Pan Am had carried nearly one million passengers. Not only did the 747 revolutionize air travel with its size, cutting the per passenger cost by half, but it also ushered in today’s quieter, more fuel-efficient high-bypass turbofan engines.

A total of 1,548 aircraft have been delivered across 22 variants of the four-engine wide-body aircraft, according to Boeing. Ranging from the 747SP, with a shortened fuselage designed for ultra-long-range flights, to the 747-400 with upgrade technology in the cockpit, to today’s 747-8, with a lengthened fuselage and wings redesigned for fuel efficiency.

The 747 has been popular with passenger and cargo airlines as well as government operators.

The U.S. Air Force has operated six highly modified 747-200 aircraft over the years, and four serve as the National Emergency Airborne Command Post. Known in the military as E-4s, aerial refueling can extend missions for a week without landing. Since delivery in 1990, the most famous pair is better known as Air Force One while the president is aboard.

NASA has operated three 747s over the years.

A pair of passenger 747-100s were purchased from airlines and modified to give space shuttle orbiters a piggyback ride home after landing at the Edwards Air Force Base in California. When heavy rain in California flooded those runways during STS-3, a Shuttle Carrier Aircraft (SCA) ferried the Space Shuttle Columbia from White Sands, New Mexico to the Kennedy Space Center.

Had the shuttle needed to abort a launch during a brief window of about four minutes, a space shuttle orbiter might have landed in Myrtle Beach, South Carolina; Wilmington, North Carolina or Marine Corps Air Station Cherry Point, North Carolina. Their 8,000-plus foot runways could handle that launch abort scenario, including the 747 that would ferry it back to Florida.



NASA’s other 747 is still in operation as the Stratospheric Observatory for Infrared Astronomy (SOFIA). This 747SP had a complete career with Pan Am and United Airlines from 1977-1997, before NASA modified it to serve as a platform for astronomy.

The fuselage behind the wing was sealed, a three-car-garage sized hole was cut in the plane, a 1.5-ton door which opens in flight was added, and a 17-ton telescope was mounted inside. There are only 30 in the world bigger, but this one can be positioned nearly anywhere in the world and sees in the critical infrared portion of the electromagnetic spectrum.



Dense regions of gas and dust where stars are born are hidden from optical telescopes. While infrared's longer wavelengths pass through those dusty regions, water vapor in the Earth’s atmosphere can interfere with these observations. SOFIA cruises between 37,000 and 45,000 feet, above more than 99 percent of that water vapor.

Dr. Rachel Smith heads the Astronomy & Astrophysics Research Lab at the North Carolina Museum of Natural Sciences. She recently flew on SOFIA in her study of the chemistry of protoplanetary material — the gas, ice, and dust that will eventually make up planets. Smith and her co-authors published their findings in November in the Astrophysical Journal Letters.

“We were looking for sulfur dioxide (SO2), a reservoir of sulfur — one of the important elements in the chemistry of forming planetary systems and the molecules needed for life,” Dr. Smith explained. “These forming stars are analogues to our own solar system. Studying a young stellar object like MonR2 IRS3 can help put our solar system into a Galactic context of other planetary systems that exist or are forming today.”



MonR2 is a region of young stars within the constellation of Monoceros, below Gemini and to the left of Orion.

The flight took Smith and a crew across a dozen states and into Canada. Even at the stratospheric altitude of 40,000 feet, there are still more than 42 miles of atmosphere between the telescope and “space”. To correct for this, observations are calibrated using a well known hot, bright star such as Vega or Sirius.

“I love observing and would fly on SOFIA again in a heartbeat. It’s not like going to space, but being part of the mission team made it feel close” Smith said.



SOFIA’s more than 40-year-old airframe continues to serve, thanks to parts from both shuttle carriers and the retired Airborne Laser Test Bed (YAL-1), once equipped with a megawatt laser to destroy incoming ballistic missiles. YAL-1 helps keep the Air Force’s E-4s flying as well.



That first 747, which served as a test aircraft for many years contributing to the 747, 757, and 787 programs, is on display at the Museum of Flight in Seattle. Shuttle carrier aircraft N905NA is on display at Space Center Houston (with a mockup of the shuttle orbiter mounted atop that once was displayed at the Kennedy Space Center). SCA N911NA can be seen at the Joe Davies Heritage Airpark in Palmdale, California when it is not being used for spare parts for SOFIA.

Tony Rice is a volunteer in the NASA/JPL Solar System Ambassador program and software engineer at Cisco Systems. You can follow him on twitter @rtphokie.