Sign up for our daily newsletterEmail addressSign upI would like to subscribe to The Points Guy newsletters and special email promotions. The Points Guy will not share or sell your email. See privacy policy.From Etihad’s A380 Apartment to Singapore Suites, frequent flyers get to travel on some pretty incredible planes. But, while there are no shortage of opportunities to burn lots of miles for a fantastic long-haul journey, some experiences are a bit out of reach of even the most miles-rich consumers.SOFIA’s main deck. Photo courtesy of Chris Sloan.One such flight is on NASA’s heavily modified Boeing 747SP, the Stratospheric Observatory for Infrared Astronomy, or SOFIA for short. The in-flight observatory allows scientists to conduct infrared astronomy observations at 41,000 feet, offering a clearer picture since there’s very little water vapor in the air at that level. This 747 flew passengers as part of United’s fleet for nearly 10 years, until it was retired in 1995 and later modified and returned to service. It’s been operating as an in-flight laboratory since 2010.SOFIA offers several rows of Lufthansa’s old business-class seats. Photo courtesy of Chris Sloan.While we haven’t had a chance to experience SOFIA, Chris Sloan of Airways Magazine was kind enough to share photos from his recent flight, which you can read about in full detail here. Chris got to spend roughly 10 hours on the plane, which flew from Palmdale airport, just north of Los Angeles, making its way up to Washington, across the Midwest and over New Mexico before finally returning to Palmdale.You can experience SOFIA in Part 1, Part 2 and Part 3 of Chris’ adventure.