posted May 08, 2014
Interviewed by Lindsay Chaney
Dr. Martin Ross, senior project engineer in the Launch Systems Division, leads research concerning the effects of space systems on the stratosphere at The Aerospace Corporation. A 26-year Aerospace employee, he is the lead author of a recently published scientific paper in a new journal from the American Geophysical Union called Earth’s Future. The paper, published April 28, is titled “Radiative Forcing Caused by Rocket Engine Emissions.”
In his own words, Ross discusses his new research and what influenced him to become an engineer.
Radiative Forcing, What it Is
Radiative forcing is the change in the radiation balance between the sun and the Earth possibly caused by human activities.
One of the things I’ve become interested in over the past few years is that space activities are a potentially important impact to this radiation balance above about 20 kilometers.
That includes rocket exhaust and re-entering space debris that burns up.
I find it amusing and troubling that when the press reports on re-entering satellites they always talk about things burning up like they disappear. In fact, a cloud of particles is created that affects the radiation balance.
As far as rocket exhaust goes, we looked at gases such as CO2 and H2O, and particles such as soot from hydrocarbon-fueled rocket engines and alumina from solid rocket motors. What we found was that CO2 is a total non-issue by orders of magnitude compared with the particles.
It’s disturbing to see in the press discussions of CO2 from rockets like it means anything substantial. Surprisingly, it’s all about the soot.
Effects of Alumina
The other surprise we found was that alumina particles were known to reflect sunlight, so people thought they would cool the atmosphere. But we found that alumina absorbs upwelling infrared energy from the Earth and this absorption wins out over the reflection of sunlight.
So, alumina is a net warmer of the Earth’s atmosphere, exactly the opposite of the commonly accepted wisdom.
This is important because solid rocket motor use is increasing again after the retirement of the space shuttle, which accounted for much of the solid motor use before 2010.
Earth’s Future is a new journal trying to establish a new point of view for Earth systems science. It’s a cross-discipline look at how the Earth will look decades from now if current trends continue.
There’s a little bit of philosophy in the journal, which resonates with my interest in academic philosophy. Since 2004, I’ve been an adjunct professor at Embry-Riddle Aeronautical University, where I teach a class in the history of scientific thought.
Our paper is one of the first to be published in Earth’s Future.
A lot of the calculation heavy lifting was done by Patti Sheaffer in the labs, who is the co-author of the paper.
My father read to me in a big green chair every night, this book called “You Will Go to the Moon” and I thought that was the greatest thing ever – going to the moon.
Both of my parents were teachers, so they showered me with books. Every time I expressed an interest in something, books would appear, as if by magic.
My father attended summer school at the University of Michigan getting his master’s degree, so we spent summers in Ann Arbor. My brother and I knew every inch of that city by the time he was done.
So there was no question I was going to U of M. I didn’t apply anywhere else.
Largest Football Stadium in the World
I always sold my tickets to the U of M football games, so I could buy more books, LOL. They have the largest football stadium in the world, you know – not that I ever attended a game.
I got a good engineer’s education.
When I graduated I went to Ford Aerospace for two years, working guidance and control stuff.
UCLA and Aerospace
I ended up at UCLA because I met my future adviser at a meeting held by the American Geophysical Union, where I was going to talk about the influence of the magnetosphere on control systems of satellites.
This guy, Dr. Gerald Schubert, to whom I owe a great debt of gratitude, reignited within me my love of pure science.
I spent six years at UCLA getting a masters and Ph.D. in space physics. Dr. Schubert was a fantastic adviser.
By the time I graduated, Jerry was a consultant at Aerospace, and he talked me into coming here.
Jerry, if you’re reading this, I’ll get you.