Before revision: NASA's Altus II UAV developed under ERAST The Environmental Research Aircraft and Sensor Technology, or ERAST program was a NASA program to develop cost-effective, slow-flying unmanned aerial vehicles (UAVs) that can perform long-duration science missions at altitudes above 60,000 feet .
After revision: NASA's Altus II UAV developed under ERAST The Environmental Research Aircraft and Sensor Technology, or ERAST program was a NASA program to develop cost-effective, slow-flying unmanned aerial vehicles (UAVs) that can perform long-duration science missions at altitudes above .