Constructed in 1976 and 1977, Mass Driver 1 was an early demonstration of the concept of the

mass driver A mass driver or electromagnetic catapult is a proposed method of non-rocket spacelaunch which would use a linear motor to accelerate and catapult payloads up to high speeds. Existing and contemplated mass drivers use coils of wire energized by e ...

, a form of electromagnetic launcher, which in principle could also be configured as a rocket motor, using asteroidal materials for reaction mass and energized by solar or other electric power. As originally envisioned, the mass driver was intended to launch payloads from a lunar base to L5, the fifth Lagrange point in which a stable orbit can be maintained. This is where

Gerard K. O'Neill Gerard Kitchen O'Neill (February 6, 1927 – April 27, 1992) was an American physicist and space activist. As a faculty member of Princeton University, he invented a device called the particle storage ring for high-energy physics experiments. L ...

proposed building a space colony (of the five Lagrange points, only L4 and L5 are truly stable, both for the real physical Earth/Moon system as well as for the ideal restricted 3-body case). The model consisted of a series of some 20 drive coils through which a small armature (called the bucket) traveled, pushed by the pulsed magnetic fields of the drive coils. The bucket rode on four rails made from copper plumbing tubes, through which was fed direct current from several car batteries connected in series. It was an epoxy glass cylinder, roughly 10 cm in diameter by 20 cm long, wrapped with a coil of aluminium wire, energized by the batteries. The copper rails were mounted onto the interior of the drive coils, and the bucket was held onto the copper rails by spring-loaded beryllium copper strips with automotive

carbon brushes A brush or carbon brush is an electrical contact which conducts current between stationary wires and moving parts, most commonly in a rotating shaft. Typical applications include electric motors, alternators and electric generators. The lifespa ...

mounted on the ends. The passage of the bucket depressed microswitches which triggered the discharge of capacitors through the drive coils. The current in the bucket coil interacted, by the Lorentz force, with the pulsed magnetic fields from the drive coils to accelerate the bucket. When the bucket coil was cooled by liquid nitrogen to reduce its electrical resistance, it was able to achieve an acceleration of around 30 ''g'' (300 m/s²). The mass driver was inspired and designed by

Princeton University Princeton University is a private research university in Princeton, New Jersey. Founded in 1746 in Elizabeth as the College of New Jersey, Princeton is the fourth-oldest institution of higher education in the United States and one of the ...

(who was on sabbatical at MIT during the 1976–77 academic year) and

Henry Kolm Henry Herbert Kolm (September 9, 1924 in Vienna – July 29, 2010 in Concord, Massachusetts) was an American physicist associated with Massachusetts Institute of Technology (MIT) for many years, with extensive expertise in high-power magnets and ...

MIT The Massachusetts Institute of Technology (MIT) is a private land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern technology and science, and is one of the m ...

. It was built under their direction by students at MIT, largely using material scavenged from the scrap heap at the Bitter Magnet Lab at MIT. A demonstration at the May 1977 Princeton University Space Manufacturing Facilities Conference was covered by '' Nova''. Ultimately O'Neill and Kolm hoped to launch payloads to escape velocity from Earth, thus reducing the cost of space launch to only about ten dollars a pound, the cost of electric energy, by eliminating the need to launch rocket fuel. Further development awaits the day when the space launch market off-Earth is large enough to justify the cost. The idea for the mass driver may have come from the 1966

Robert A. Heinlein Robert Anson Heinlein (; July 7, 1907 – May 8, 1988) was an American science fiction author, aeronautical engineer, and naval officer. Sometimes called the "dean of science fiction writers", he was among the first to emphasize scientific accu ...

book ''

The Moon Is a Harsh Mistress ''The Moon Is a Harsh Mistress'' is a 1966 science fiction novel by American writer Robert A. Heinlein about a lunar colony's revolt against absentee rule from Earth. The novel illustrates and discusses libertarian ideals. It is respected for i ...

''. Heinlein referred to a similar device as an "induction catapult".

References

Image: pictured (L to R) are Kevin Fine, Jonah Garbus, G.K. O'Neill, Henry Kolm, and

Eric Drexler Kim Eric Drexler (born April 25, 1955) is an American engineer best known for studies of the potential of molecular nanotechnology (MNT), from the 1970s and 1980s. His 1991 doctoral thesis at Massachusetts Institute of Technology was revised and ...

. * {{cite book , title=The Moon Is A Harsh Mistress , last=Heinlein , first=Robert A. , year=1966 , publisher=G. P. Putnam's Sons , location=New York Vehicles introduced in 1977 Space colonization Space launch vehicles of the United States