Timberwind column reflects simple misconceptions
Matthew H. Hersch 94's column detailing the merits of a current nuclear rocket program was certainly well intentioned but missed the mark ["Some really bad ideas deserve a second chance," April 12].
I took great interest in it primarily because my graduate thesis is related to the benefits of using nuclear thermal propulsion for Mars mission applications.
The story that broke recently [The New York Times, April 3, as well as The Boston Globe, same date] stated that the United States is currently developing a nuclear launch vehicle for use in applications for the Strategic Defense Initiative.
I don't question the veracity of the story, but what bothered me was the unstated but nevertheless clear implication that the launch vehicle would be all-nuclear, which is, as far as I am aware, not even a technological possibility, for now or the foreseeable future.
The Times never came out and actually said that the engine would take the vehicle off the pad, but it appeared to be purposefully vague. Hersch, and no doubt many others, jumped to the natural but incorrect conclusion. A friend in my department who is quite familiar with my work got exactly the same impression, and he's reasonably well-informed on the topic!
The Nuclear Engine for Rocket Vehicle Application (NERVA) engines Hersch mentions were large and developed very low thrust-to-weight -- so low, in fact, that they could never be considered for first stage, off-the-pad use.
To get off the launch pad requires very high thrust-to-weight, something obtainable only with chemical engines such as those used to power the space shuttle. NERVA -- and its more recent successors, such as the particle bed reactor Hersch describes -- were intended to be used for upper-stage use only, once the vehicle was well out of the atmosphere.
Never was it suggested that the nuclear rocket should take the launch vehicle off the pad -- the radiation levels near the engine would prohibit this, were it even possible. Yet The Times seems to imply that this is what the military is planning.
Hersch bought into that implication, and that, I'm afraid, was the intent of the article -- to get people mad at SDI.
The public clearly needs to be better informed about all things nuclear. The Times article -- and, indirectly, Hersch's -- did a great disservice to all of us by providing only a part of the true story, and may end up getting a very worthwhile research program canceled on the basis of a simple misconception. What a tragedy.
Fred G. Kennedy '90->
Department of Aeronautics->