NASA is in the midst of its first phase of flight tests to determine the effects of alternative biofuels on the emissions and performance of jet engines flying at altitude.
The program is called the Alternative Fuel Effects on Contrails and Cruise Emissions, or ACCESS, according to Dr. Ruben Del Rosario, project manager of NASA’s Subsonic Fixed Wing project. The goal is to investigate how biofuels perform compared with traditional jet fuel and also to measure the environmental impact of biofuels. The results of the tests are significant because of the growing popularity of biofuels for both the U.S. Air Force and Navy as well as private sector aviation.
During the ACCESS tests, the space agency’s highly modified Douglas DC-8, which normally is used as a flying laboratory, will conduct a series of flights at altitudes as high as 40,000 feet, while a NASA Falcon HU-25 aircraft follows behind at distances of between 300 feet and more than 10 miles, according to Del Rosario. The flights will take place primarily over restricted airspace over Edwards Air Force Base in California.
ACCESS is the outgrowth of earlier preliminary research on biofuels and jets. “It was born out of two previous experiments that we conducted in 2009 and 2011 at NASA’s Dryden Aircraft Operations Facility,” Del Rosario explains. During those tests, ground-based instruments measured the exhaust emissions of the DC-8 while the plane was parked on a ramp at the Palmdale, California, facility.
“During the ground tests, we took very detailed emission measurements, measuring CO2 [carbon dioxide], different oxides, different particulates, measuring sulfur, all the different kind of emissions we could possibly measure with many other companies and institutions joining us, as well,” Del Rosario says.
Become a fan on 
Link with 
View photos on 
