In a bid to understand synthetic fuels' emissions, NASA has fitted its McDonnell Douglas DC-8 airborne laboratory's engines with sampling probes for plume chemistry detection using a quantum-cascade-laser methane isotope sensor.
The aeronautics and space agency is using 100% synthetic fuels and 50/50 blends of synthetics and regular jet fuel for its tests. It thinks synthetic fuels may have fewer particles and other harmful emissions than standard jet fuel.
Tests conducted at NASA's Dryden Flight Research Center in California saw the DC-8 stay on the ground while two synthetic fuels, derived from coal and natural gas using the Fischer-Tropsch process, were used. The Fischer-Tropsch process uses a mixture of carbon monoxide and hydrogen to create liquid hydrocarbons for fuel. The plume chemistry detecting quantum-cascade-laser is a more efficient type of laser used for spectroscopy.
"We're starting to look at just what comes out of the tailpipe of a commercial aircraft [that is burning alternative fuels]," says NASA Langley Research Center Alternative Aviation Fuel Experiment project scientist Bruce Anderson.
The research is funded and managed by NASA's fundamental aeronautics programme, which is part of the agency's aeronautics research mission directorate. NASA is working with 11 groups on the study, which include three US government agencies, five companies and three universities.
While various airlines including Virgin Atlantic and Air New Zealand have burned biofuels with in-service aircraft, those tests have dealt with performance, not emissions.