Star Driver by G. Harry Stine

For every action there is an equal and opposite reaction – thatk Newtoni- Third Law, an ironclad rule of physics. But when pilot- astronomer Mike Call arrived at a top-secret New England lab, he found that a brilliant research team had seemingly repealed that bask law and produced a device with one- way thrust-in effect the legendary “skyhook.”
Here was the key to cheap, practical space travel, to a completely new era for Earth -if only Mike and the team could…

…keep the government off their backs …counter a devious and ruthless campaign of blackmail and espionage

…and stop corporate power brokers from letting the whole project go down the tubes!