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 this difficulty would be to build our interplanetary vehicle, go to the planet that we were interested in landing on, and hover several hundred miles up. From this altitude we could send instrumented test vehicles down to the planet. If we didn't want the inhabitants of the planet, if it were inhabited, to know what we were doing we could put destruction devices in the test vehicle, or arrange the test so that the test vehicles would just plain burn up at a cert