It was six or eight months later before the subject of green fireballs came up again.  I was eating lunch with a group of people at the AEC’s Los Alamos Laboratory when one of the group mentioned the mysterious kelly-green balls of fire.  The strictly unofficial bull-session-type discussion that followed took up the entire lunch hour and several hours of the afternoon.  It was an interesting discussion because these people, all scientists and technicians from the lab, had a few educated guesses as to what they might be.  All of them had seen a green fireball, some of them had seen several.

One of the men, a private pilot, had encountered a fireball one night while he was flying his Navion north of Santa Fe and he had a vivid way of explaining what he’d seen.  “Take a soft ball and paint it with some kind of fluorescent paint that will glow a bright green in the dark,” I remember his saying, “then have someone take the ball out about 100 feet in front of you and about 10 feet above you.  Have him throw the ball right at your face, as hard as he can throw it.  That’s what a green fireball looks like.”

The speculation about what the green fireballs were ran through the usual spectrum of answers, a new type of natural phenomenon, a secret U.S. development, and psychologically enlarged meteors.  When the possibility of the green fireballs’ being associated with interplanetary vehicles came up, the whole group got serious.  They had been doing a lot of thinking about this, they said, and they had a theory.

The green fireballs, they theorized, could be some type of unmanned test vehicle that was being projected into our atmosphere from a “spaceship” hovering several hundred miles above the earth.  Two years ago I would have been amazed to hear a group of reputable scientists make such a startling statement.  Now, however, I took it as a matter of course.  I’d heard the same type of statement many times before from equally qualified groups.

Turn the tables, they said, suppose that we are going to try to go to a far planet.  There would be three phases to the trip:  out through the earth’s atmosphere, through space, and the re-entry into the atmosphere of the planet we’re planning to land on.  The first two phases would admittedly present formidable problems, but the last phase, the re-entry phase, would be the most critical.  Coming in from outer space, the craft would, for all practical purposes, be similar to a meteorite except that it would be powered and not free-falling.  You would have myriad problems associated with aerodynamic heating, high aerodynamic loadings, and very probably a host of other problems that no one can now conceive of.  Certain of these problems could be partially solved by laboratory experimentation, but nothing can replace flight testing, and the results obtained by flight tests in our atmosphere would not be valid in another type of atmosphere.  The most logical way to overcome