8 | MARCH 2020 | aerospaceamerica.aiaa.orgDo you have a puzzler to suggest? Email us at [email protected].For a head start ... nd the AeroPuzzler online on the rst of each month at
https://aerospaceamerica.aiaa.org/ and on Twitter @AeroAmMag.Climate impact
Q. Climate scientists are returning
home after delivering a presentation
about cirrus clouds. The pilot
announces, “Ah, folks, we’re taking
the shortest possible route from
Washington Dulles to Vienna this
afternoon, so sit back and relax,
knowing we’ve done all we can to
reduce this ight’s climate impact.”
The scientists let out a collective
groan. Why?
Draft a response of no more than 250 words and email
it by midnight March 3 to [email protected] for a
chance to have it published in the April issue.BURNING CLEAN
We asked you whether it’s true or false
that water vapor would be the only emis-
sions from the Space Shuttle Main Engines
or a hypothetical hypersonic air-breathing
vehicle fueled by liquid hydrogen.WINNER: The statement as written is
false. The shuttle main engines burn liq-
uid oxygen, so as long as the hydrogen and oxygen are pure, the exhaust
is water. But for the air- breathing vehicle, a large amount of nitrogen
goes into the engine, and the heat will produce nitrogen oxides, which
are a pollutant. There MIGHT be some other compounds created outside
the shuttle engine itself, if the hot exhaust is enough to trigger some
reactions in the surrounding air.Bob Parks
San Jose, California
AIAA associate fellow
[email protected]FROM THE FEBRUARY ISSUE