N5539D

N5539D is a Scaled Composites SpaceShipTwo, a single-engine jet operated by THREE FIVE JULIER LLC. SkyMeter has tracked 516 flights totalling 233 hours of airtime via ADS-B across 2 callsigns. The most frequent segment is KOXI to KOXI. Service window in our records spans 427 days. Of those flights, 2 (0.4%) carry at least one detected incident: a go-around, unstable approach, stall warning, or runway excursion. The Scaled Composites SpaceShipTwo has a maximum takeoff weight of 19,000 lb, light wake category.

About the Scaled Composites SpaceShipTwo

SpaceShipTwo is the world's first commercial suborbital spaceplane designed to carry paying passengers to the edge of space. Built by Scaled Composites and operated by Virgin Galactic, this rocket-powered vehicle represents a fundamentally different approach to spaceflight: air-launched from a carrier aircraft at 50,000 feet, it ignites a hybrid rocket motor to climb beyond 50 miles altitude before gliding back to a runway landing. The design descends from SpaceShipOne, which in 2004 became the first private crewed vehicle to reach space and won the $10 million Ansari X Prize.

Unlike traditional spacecraft that launch vertically atop expendable rockets, SpaceShipTwo takes off horizontally beneath WhiteKnightTwo, a twin-fuselage carrier jet. After release, the spaceplane fires its single hybrid rocket motor (burning hydroxyl-terminated polybutadiene rubber fuel with nitrous oxide oxidizer) for roughly 60 seconds of powered flight. The vehicle then coasts to apogee in a ballistic arc, providing several minutes of weightlessness and views of Earth's curvature against the black of space. For reentry, the twin tail booms rotate upward into a high-drag "feathered" configuration that provides inherent stability during descent through the atmosphere, a safety innovation that eliminates the need for precise computer-controlled reentry angles.

The type has faced significant development challenges. VSS Enterprise was lost in a 2014 test flight accident that killed one pilot, leading to extensive design modifications. VSS Unity, the second SpaceShipTwo vehicle, completed its first crewed spaceflight in 2018 and began commercial operations in 2023. A third vehicle, VSS Imagine, represents an evolved design with improved manufacturability. The spaceplane's operating envelope is unlike any other civilian aircraft. It reaches Mach 3+ during rocket burn and experiences reentry heating, yet lands unpowered on a conventional runway at around 200 knots.

SkyMeter has tracked flights across airframes and operators, with the largest observed operator.