Last September, a balloon floating 70,000 feet above the ground released a custom-built NASA drone. The High Altitude Shuttle System (HASS), an awkward-looking flying wing with a five-foot span and 22-pound payload, was meant to mimic a winged, suborbital spacecraft returning to Earth and re-entering controlled airspace. In other words, it was pretending to be something like Virgin Galactic’s SpaceShipTwo, one of several winged space vehicles that might enter commercial service in the coming years.
Paul De León, test campaign manager for NASA’s Flight Opportunities office, says the testers were specifically interested in how well Automatic Dependent Surveillance-Broadcast would work with suborbital flight. ADS-B, which will become the primary method of tracking nearly all aircraft by 2020, provides air traffic controllers with radar-like information where no radar exists by relying on the aircraft’s GPS and avionics to broadcast its precise location and altitude. But that system was designed for use only in FAA-controlled Class A airspace below 60,000 feet. Suborbital spacecraft will be descending through much higher altitudes.