The ALTUS II, the first of the two craft to be completed, made its first flight on May 1, 1996. With its engine at first augmented by a single-stage turbocharger, the ALTUS II reached an altitude of ... 37,000 ft during its first series of development flights at Dryden in August, 1996. In October of that year, the ALTUS II was flown in an Atmospheric Radiation Measurement (ARM-UAV) study in Oklahoma conducted by Sandia National Laboratories for the Department of Energy (DOE). During the course of those flights, the ALTUS II set a single-flight endurance record for remotely operated aircraft of more than 26 hours.
The ALTUS I, completed in 1997, flew a series of development flights at Dryden that summer. Those test flights saw the craft reach an altitude of 43,500 ft while carrying a simulated 300-lb payload, a record for a remotely operated aircraft powered by a piston engine augmented with a single-stage turbocharger.
After major modifications and upgrades, including installation of a two-stage turbocharger in place of its original single-stage unit, a larger fuel tank and additional intercooling capacity, the ALTUS II returned to flight status in the summer of 1998. The goal of its development test flights was to reach one of the major Level 2 performance milestones within NASA's ERAST program: to fly a gasoline-fueled, piston-engine remotely piloted aircraft for several hours at an altitude at or near 60,000 feet. On March 5, 1999, The ALTUS II maintained flight at or above 55,000 feet for three hours, reaching a maximum density altitude of 57,300 feet during the mission.
Later that spring, the ALTUS II flew another series of Atmospheric Radiation Measurement missions conducted by Sandia National Laboratories for the DOE. Hard-to-measure properties of high-level cirrus clouds that may affect global warming were recorded using specially designed instruments while the Altus flew at 50,000 feet altitude off the Hawaiian island of Kaua'i. Clouds both reflect incoming solar energy back to space, and absorb warm longwave radiation from the Earth's surface, keeping that heat in the atmosphere. Data from the study will help scientists better understand how these dual roles of clouds in reflecting and absorbing solar energy work, and build more accurate global climate models.
In September, 2001, ALTUS II served as the UAV platform for a flight demonstration of remote sensoring and imaging capabilities that could detect hot spots in wildfires and relay that data in near- real time via the Internet to firefighting commanders below. The demonstration, led by NASA Ames Research Center, was flown over GA-ASI's El Mirage development facility in Southern California.
In the summer of 2002, The Altus II served as the airborne platform for the Altus Cumulus Electrification Study (ACES), led by Dr. Richard Blakeslee of NASA Marshall Space Flight Center. The ACES experiment focused on the collection of electrical, magnetic and optical measurements of thunderstorms. Data collected will help scientists understand the development and life cycles of thunderstorms, which in turn may allow meteorologists to more accurately predict when destructive storms may hit. For more information on the ACES study, visit the National Space Science and Technology Center web site at the NASA Marshall Space Flight Center: http://aces.msfc.nasa.gov.
information provided by http://www.nasa.gov/centers/dryden/news/FactSheets/FS-058-DFRC.html