Clement Hal. Answer

Alvan wren, poised beside a transparent port in the side of the service rocket, gazed out with considerable interest. The object of his attention, hanging a few miles away and slowly drifting closer, was not too imposing at first glance; merely a metal globe gleaming in the sunlight, the reflection from its surface softened by a second, concentric, semitransparent envelope. At this distance it did not even look very large; there was no indication that more than seventy years of time and two hundred million dollars in effort had already been expended upon that inner globe, although it was still far from completion. It had absorbed in that time, on an average, almost a quarter of the yearly income from a gigantic research sinking fund set up by contributions from every institution of learning on Earth; and — unlike most research projects so early in their careers — had already shown a sizable profit.
More detail began to show on both spheres, as the rocket eased closer. The outer envelope lost its appearance of translucent haze and showed itself to be a silver lacework — a metallic mesh screen surrounding the more solid core. Wren knew its purpose was to shield the delicate circuits within from interference when Sol spouted forth his streams of electrons; it was all he did know about the structure, for Alvan Wren had a very poor grounding in the physical sciences. He was a psychologist, with enough letters after his name to shout down anyone who decried his intelligence, but the language of volts and amperes, ergs and dynes was strange to him.
The pilot of the rocket was not acquainted with his passenger, and his remarks were not particularly helpful.
We ought to make contact in about fifteen minutes, he said. We’re not supposed to use rockets close to the machine, and we have to brake down to safe contact speed at least twenty miles away.
That’s why the final approach takes so long. They don’t like anything they can’t account for in the neighborhood — and that goes for stray electrons and molecules, as well as atomic converters.
What is their objection to rocket blasts, provided they’re not fired directly at the station? asked Wren. What influence could a jet of gas even one mile away possibly have on their machinery?
None, directly; but gases diffuse, and some of the elements in rocket fuel are easily ionized in sunlight. The boys in there claim that the firing of a rocket blast five miles from the outer sphere will disturb some of their circuits, when the molecules which happen to leak inside their screen are ionized there. It sounds a little farfetched to me, but that’s not my line...