Editing Mass driver (section)

==Hybrid mass drivers==

A mass driver on a [[spacecraft]] could be used to "reflect" masses from a stationary mass driver. Each deceleration and acceleration of the mass contributes to the [[momentum]] of the spacecraft.  The lightweight, fast spacecraft need not carry [[reaction mass]], and does not need much electricity beyond the amount needed to replace losses in the electronics, while the immobile support facility can run off power plants able to be much larger than the spacecraft if needed.  This could be considered a form of [[beam-powered propulsion]] (a macroscopic-scale analogue of a [[particle beam]] propelled magsail).  A similar system could also deliver pellets of fuel to a spacecraft to power another propulsion system.<ref name="Singer1979">{{cite report |last1=Singer|first1=C.E.|year=1979|doi=10.2172/5770056 |title=Interstellar Propulsion Using a Pellet Stream for Mass Transfer |url=http://www.osti.gov/bridge/servlets/purl/5770056-4HSXxH/5770056.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://www.osti.gov/bridge/servlets/purl/5770056-4HSXxH/5770056.pdf |archive-date=2022-10-09 |url-status=live |access-date=May 9, 2011}}</ref><ref>{{cite web |url=http://www.centauri-dreams.org/?p=458 |title=Interstellar Flight Using Near-Term Technologies |access-date=May 9, 2011 |work=Centauri Dreams |first=Paul |last=Gilster |date=April 20, 2005}}</ref><ref name = momentumtransfer>[http://www.freepatentsonline.com/5305974.pdf U.S. Patent #5305974, Spacecraft Propulsion by Momentum Transfer]. Retrieved May 9, 2011.</ref><ref>{{cite book |chapter-url=https://books.google.com/books?id=tIfJM8Nu8iYC&pg=PA120 |title=Deep Space Probes: To The Outer Solar System and Beyond |page=120 |chapter=8.5: A Toroidal Ramscoop |first=Gregory L. |last=Matloff |publisher=Springer |year=2005 |isbn=9783540247722 |access-date=May 9, 2011}}</ref>

Another theoretical use for this concept of propulsion can be found in [[space fountain]]s, a system in which a continuous stream of pellets in a circular track holds up a tall structure.