 What is the purpose of “touching helmets”?
By H. B. FYFE [Transcriber's Note: This etext was produced from Worlds of If Science Fiction, September 1961. Extensive research did not uncover any evidence that the U.S. copyright on this publication was renewed.] The glowing semi-disk of Jupiter was more than half a million miles distant. "Try not to be simple—for once!" growled Jeffers. "A little percentage here and there on the cargoes never shows by the time figures get back to Earth. Maybe they live soft back on Earth since the mines and the Jovian satellite colonies grew; but they were out here in the beginning, most of them. "You know I took this piloting job just to scrape up money for an advanced engineering degree back on Earth. It had been built for Ganymede, but not for Jeffers. "You can ease out whenever your contract's up. Five hundred credits a week base pay, five hundred for hazardous duty. How else can you get pilots out to Jupiter?" "Okay I can't fire you legally—as long as you report for work," grumbled Jeffers, by now a shade more ruddy. Because you're off the Callisto run as of now! Sit in your quarters and see if the company calls that hazardous duty!" He winked and walked out, deliberately leaving the door open behind him so as to enjoy the incoherent bellowing that followed him. Tolliver began to have his doubts the next day; which was "Tuesday" by the arbitrary calender constructed to match Ganymede's week-long journey around Jupiter. His contract guaranteed a pilot's rating, but someone had neglected to specify the type of craft to be piloted. On the bulletin board, Tolliver's name stood out beside the number of one of the airtight tractors used between the dome city and the spaceport, or for hauling cross-country to one of the mining domes. He soon found that there was nothing for him to do but hang around the garage in case a spaceship should land. The few runs to other domes seemed to be assigned to drivers with larger vehicles. Sometimes there's no reason but them for sending a ship back with a crew instead of in an economy orbit. Under a portable, double-chambered plastic dome blown up outside the ship's airlock, a crewman helped him load two trunks and a collection of bags into the tractor. Her trim coiffure was a shade too blonde which served to set off both the blue of her eyes and the cap apparently won from one of the pilots.
 To communicate without using the radio.
 To communicate without using the radio.  To share oxygen.  To maintain the vacuum seal of the suits.  To keep the dust out.