“…the newly-formed Special Aeronautics Department began as a small collection of office modules and scaffolding atop Alpha-1. Their crowning achievement was taking the powerplant of a Sprat and turning it into the SAD-1, or ‘Sookybird’ as it came to be known. A light, powered glider; manned by a single pilot and fired via a magnetic slingshot from a specially-designed flight gantry. It was as much an exercise in raising the spirits of the colonists as it was a technical achievement.”
After the murder, we came to appreciate the limitations of satellite photography.
Cane had disappeared into that vast area beyond the colonies and seismological relay stations that we had slowly come to call the Periphery, and neither satellites nor trackers could find him. Only weeks later had a long-range team chanced upon the degrading, short-range beacon of Cane’s vehicle.
Satellite mapping of Fram was an ongoing task. We had since Planetfall mapped a swath of Fram, centred on the equator and ranging between twenty and twenty-five degrees north and south latitudes. We had accomplished this with only two satellites, locked in opposing orbits. There were, of course, over a dozen different satellites in orbit of our world, but most of these were space observatories examining the Universe in various wavelengths, or monitoring the Amundsen Ring for potential impactors.
Yet the ground resolution of the images provided by these mapping satellites was in some cases insufficient for our needs. There were other limitations beyond low ground resolution. The manoeuvrability of satellites was restricted to their planned orbit, in turn circumscribed by delta-vee and payload. Because of this, data collection was slow, as evidenced by the limited coverage of Fram’s surface achieved in the months since Planetfall. Data collection was also dependent on weather, and, although cloud cover was less a restriction on Fram than the worlds and moons of Sol, dust storms were common, and in the polar latitudes these storms were violent and long-lasting. Moreover, our pool of satellites was limited to those brought from Sol aboard the Quoqasi and the Mayflower; although we could potentially build more, the costs of construction and launch were prohibitive.
Thus, we turned to cheaper alternatives to supplement the data collection of satellites. Two contending alternatives were submitted to the Special Aeronautics Department: an unmanned aerial vehicle, and a low-altitude, manned aircraft. Various designs for each alternative were explored, from fixed-wing aircraft to VTOL rotorcraft, to airships, to both autonomous and guided UAVs. Almost every design responded to Fram’s thick atmosphere with differing wing shapes. Some of these shapes appeared to the eyes of creatures that evolved on a world of comparatively thin air as impossible, or delicate, as though no lift could possibly be imparted on such a shape. The most creative of designs was for a UAV with sets of wings like those of a dragonfly which, through a complex motion calculated to reduce drag, paddled through the air.
Fram’s atmosphere imposed further limitations. Its thickness provided more lift, certainly, but that density also required more of the aircraft’s engine for propulsion. Designers looked at jet engines, fuelled by SiH4, an oxidiser that readily burned in a carbon dioxide atmosphere. But silane was both difficult to manufacture and extremely toxic. Other methods of propulsion were examined, and these methods would be balanced by the requirements of power and endurance.
The advantages of a low-altitude photographic platform were readily apparent. Ground resolution would be increased, and data collection would be less constrained by weather. The ability to follow more complicated flight paths offered the geologists a better perception of the depth and scale of geological features; while increased resolution would help the xenobotanists identify clusters of methanogens. Moreover, these platforms offered real-time data – which would become important for search-and-rescue as we grew outward from the colonies and further explored our world.
And so there was some amount of compromise behind the accepted design: the SAD-1. It was a manned vehicle, which reduced its endurance, but also reduced the complexity of its design. The Special Aeronautics Department accepted that endurance was less an issue while the Colonies remained young, as most of the SAD-1′s work would be within two of three hours’ flight of its airbase atop Alpha-1. It was powered by solar-electric cells that lined the surfaces of its wings, and these electric cells could be powered by lasers beamed from the surface. The SAD-1 was propelled by two turboshaft engines mounted in the bases of its wings, which produced free turbine shaft power that spun rear-mounted propfans. Flanking the fuselage was a sophisticated sensor suite of electromagnetic spectrum sensors – infrared, ultraviolet, microwave – laser spectroscopes, and geomagnetic sensors. Mounted beneath the SAD-1′s fuselage was a super-wide angle camera, composed of four digital cameras mounted in overlapping optical axes.
At some point along the length design process, the name ‘Sookybird’ was attached to the SAD-1, and by the time of its maiden flight that moniker had stuck. The vehicle was launched from the upper heights of Alpha-1 using the same kind of electromagnetic catapult installed at Wisting Base on Amundsen. There were sparse crowds of interested onlookers, mostly colonists of Alpha-1, gathered along the ridge of the crater. Not many of those gathered appreciated the irony that the Sookybird’s first high-resolution mapping mission was of the Henderson Ridge, where Cane had murdered his partner and vanished into the Periphery…