In many of
Jerry Pournelle's novels, and the ones he collaborated with
Larry Niven, there exists a device to travel between systems. It's called the Alderson Drive.
Scientists at
Caltech develop the Alderson Drive. This
interstellar space drive is based on the discovery that instantaneous travel is possible between any two "adjacent" stars, if a ship is located at the correct "
Alderson Point". Thus the problem of travel between star systems is reduced to the problem of travel within star systems.
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Jerry Pournelle
The Alderson Point is directly related to the number of stars, and the brightness of each star. In
The Gripping Hand a new protostar is formed in the Mote Prime system shifting both the original Alderson Point and creating a new Alderson Point. When making a 'Jump' between systems, the crew suffer what is called 'Jump Shock'. The
Moties are affected more by Jump Shock than Humans, this was used to our advantage in
The Gripping Hand. Also, if computers are active during a Jump they will be irreperably damaged, so they must be shutdown. This causes many problems, especially in combat situations. The computers must pass several selfchecks before they are considered usable.
http://www.chronology.org/noframes/pournelle/timeline.html