The Mini-Sniffer program began in 1975 as an unmanned aerial vehicle designed to conduct air sampling at high altitudes. Developed by the NASA Dryden Flight Research Center, the Mini-Sniffer was designed as a cheaper alternative to manned high altitude aircraft. The Mini-Sniffer I was built with canards, swept wings and was powered by a small two stroke gas powered go-kart engine. After a hard landing, it was decided to modify the aircraft into a new design. The modifications included removing the canards and adding wing tips and tail booms. The redesign also added a gyroscope allowing the aircraft to remain level by rudder inputs alone. The modified Mini-Sniffer II on display here flew twenty flights up to altitudes of 20,000 feet.
The follow up design was the larger but lighter Mini-Sniffer III. The Mini-Sniffer III was powered by a non-air-breathing hydrazine engine that could take the aircraft and its payload up to 90,000 feet. There were also proposals to explore the atmosphere of Mars with Mini-Sniffer III drones. Unfortunately, the Mini-Sniffer III only flew one flight to 20,000 feet before hydrazine started leaking. The aircraft never flew again and the program was canceled.
Pima Air & Space Museum