ran a story
about how Helios, the world’s first unmanned plane intended as a telecom tower in the sky, has a Mac for its “brain.” After seeing some of the related discussions, Graham Gyatt, who designed and developed most of the software for the systems used to operate the aircraft, contacted MacCentral to clarify some issues regarding the use of Macs by AeroVironment, the company working on the Helios Solar Aircraft project.
The on-board flight control computer is a custom, dual redundant design (running Motorola 68K processors) that doesn’t involve any Apple products. However, all the software for it is developed on and uploaded from a Mac, Gyatt said.
“At 100,000 ft, the air temperature is about -50 [degrees Fahrenheit] (and we see even colder temperatures on the way up) and the air density is only about 1 percent of that at sea level — a challenging environment, well outside the specs of commercial products,” he told MacCentral.
As our article noted, the Ground Control Station (GCS) uses several PowerMacs to display and analyze real time data from the aircraft, and the pilot and engineers use this information to control the aircraft. A PC was only used briefly for the GCS back in the early 80s in the preliminary stages of the program, but has not been used since, Gyatt said.
“The fuel cell-based energy storage system, which will allow the aircraft to maintain altitude through the night, is under development, but has not yet flown,” he added. “The record flight in August involved a simple climb and descent profile that did not require a significant amount of propulsion power after dark and used small battery packs to keep the avionics running at night.”