How NASA’s Boeing 747 Telescope Works

NASA operates a particularly unique 747 on its observer missions. The modified 747SP carries SOFIA or Stratospheric Observatory for Infrared Astronomy, a reflective telescope that allows scientists to study the solar system. The telescope onboard observes the infrared universe and monitors events such as the formations of new stars and solar systems.

NASA uses a modified 747SP for its SOFIA missions, which features a retractable door for telescope use during the flight. Photo: NASA/Carla Thomas

Special mission

The 747SP in use for the SOFIA telescope is a 44-year-old aircraft. Registered N747NA, the plane initially came into service with Pan Am in 1977, before going to United in 1986, according to NASA finally acquired the plane in 1997, where it underwent heavy modifications to prepare it for its new role. The 747 has found its way into a number of space projects over the years.

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After multiple delays to the project due to funding and operating issues, the plane made its first test flight in 2009, which saw the telescope door open for the first time. On May 26th 2010, SOFIA returned its first image of the solar system, beginning formal operations.

SOFIA Telescope 747SP
SOFIA returned its first images in May 2010, marking a new front in observations. Photo: NASA/Jim Ross via Wikimedia Commons

The SOFIA telescope is a joint project between NASA and the German Aerospace Center (DLR), an 80-20% partnership. The plane carries the flags of both the US and Germany on the fuselage, with the insignia of NASA and DLR on the tail.

The telescope

The primary purpose of this NASA 747 is for astronomy, more particularly, to capture infrared images of the solar system. Flying at an altitude between 38,000 and 45,000 feet on the 747 allows the telescope to operate above 99% of the earth’s infrared-blocking atmosphere. This means SOFIA can capture images not possible from ground-based telescopes.

The telescope operates during 10-hour overnight flights, capturing a range of images at this time. Through a large door on the left side of the aircraft, the telescope looks out of the aircraft and uses instruments to observe multiple infrared wavelengths. The instruments onboard include an array of cameras, spectrometers, and polarimeters.

SOFIA 747SP Telescope Door
The telescope door opens during the flight to capture images using the array of instruments onboard. Photo: NASA/Carla Thomas via Wikimedia Commons

The SOFIA telescope is by far the largest telescope ever mounted on a plane and opens a new frontier in astronomical exploration. The telescope can also carry special instruments depending on the mission, making it a versatile tool for scientists. The retractable door makes it a unique aviation feature too.

Significant events

The 747SP has been in active use, with the ability to conduct up to 100 flights a year. For most of the year, the plane can be found undertaking missions from Armstrong Flight Research Center in Palmdale Regional Airport, California. However, for two months a year, the plane operates from Christchurch International Airport in New Zealand for celestial observations in the Southern Hemisphere.

SOFIA 747SP New Zealand
SOFIA spends most of its time in Palmdale, California and two months in Christchurch, New Zealand. Photo: NASA/Waynne Williams

The plane has made several notable observations, including finding oxygen in the Mars atmosphere and studying Pluto’s atmosphere. Due to the current health crisis, the aircraft was grounded in March and the New Zealand deployment canceled. However, NASA already has plans for this important aircraft and will keep it in service for years to come.

What do you think about this special 747SP? Let us know in the comments!