20:
539:
1742:
2446:
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360:, with too high a fraction of energy going into accelerating propellant not used yet. Higher exhaust velocity has both benefit and tradeoff, increasing propellant usage efficiency (more momentum per unit mass of propellant expelled) but decreasing thrust and the current rate of spacecraft acceleration if available input power is constant (less momentum per unit of energy given to propellant).
127:
by gas-phase switches (which still often have a niche in extreme pulse power applications). However, energy can be stored inductively in superconducting coils. A 1 km long mass driver made of superconducting coils can accelerate a 20 kg vehicle to 10.5 km/s at a conversion efficiency of 80%, and average acceleration of 5,600 g.
379:
with fractional-lightspeed exhaust velocity for tiny particles, trying to use extreme exhaust velocity to accelerate a far slower spacecraft could be suboptimally low thrust when the energy available from a spacecraft's reactor or power source is limited (a lesser analogue of feeding onboard power to
186:
In some designs, the payload would be held in a bucket and then released, so that the bucket can be decelerated and reused. A disposable bucket, on the other hand, would avail acceleration along the whole track. Alternatively, if a track were constructed along the entire circumference of the Moon (or
126:
For a given amount of energy involved, heavier objects go proportionally slower. Lightweight objects may be projected at 20 km/s or more. The limits are generally the expense of energy storage able to be discharged quickly enough and the cost of power switching, which may be by semiconductors or
383:
For instance, if limited onboard power fed to its engine was the dominant limitation on how much payload a hypothetical spacecraft could shuttle (such as if intrinsic propellant economic cost was minor from usage of extraterrestrial soil or ice), ideal exhaust velocity would rather be around 62.75%
374:
varies with the ratio of exhaust velocity to vehicle velocity at the time, but near maximum obtainable specific impulse tends to be a design goal when corresponding to the most energy released from reacting propellants). Although the specific impulse of an electric thruster itself optionally could
146:
With the proliferation of reusable rockets to launch from Earth (especially first stages) whatever potential might have once existed for any economic advantage in using mass drivers as an alternative to chemical rockets to launch from Earth is becoming increasingly doubtful. For these reasons many
134:
concept, would require considerable capital investment. The Earth's relatively strong gravity and relatively thick atmosphere make the implementation of a practical solution difficult. Also, most if not all plausible launch sites would propel spacecraft through heavily-traversed air routes. Due to
110:
Mass drivers need no physical contact between moving parts because they guide their projectiles by dynamic magnetic levitation, allowing extreme reusability in the case of solid-state power switching, and a functional life of – theoretically – up to millions of launches. While marginal
739:
The stars of this conference were
Professor Henry Kolm of Massachusetts Institute of Technology and the group of student volunteers who built the first mass driver In its best test, the mass driver prototype produced an acceleration of thirty-three gravities. This is more than Dr. O'Neill had
261:
A mass driver on Earth would usually be a compromise system. A mass driver would accelerate a payload up to some high speed which would not be enough for orbit. It would then release the payload, which would complete the launch with rockets. This would drastically reduce the amount of velocity
289:
for passengers, is proportional to velocity squared. For instance, half of the velocity goal could correspond to a tunnel a quarter as long needing to be constructed, for the same acceleration. For rugged objects, much higher accelerations may suffice, allowing a far shorter track, potentially
175:
part spaces the coils at constant distances, and synchronizes the coil currents to the bucket. In this section, the acceleration increases as the velocity increases, up to the maximum that the bucket can take. After that, the constant acceleration region begins. This region spaces the coils at
488:. Dr. Northrup built prototype coil guns powered by kHz-frequency three-phase electrical generators, and the book contains photographs of some of these prototypes. The book describes a fictional circumnavigation of the moon by a two-person vehicle launched by a Northrup electric gun.
123:, his next model had an order-of-magnitude greater acceleration after a comparable increase in funding, and, a few years later, researchers at the University of Texas estimated that a mass driver firing a 10 kilogram projectile at 6000 m/s would cost $ 47 million.
162:
Most serious mass-driver designs use superconducting coils to achieve reasonable energetic efficiency (often 50% to 90+%, depending on design). Equipment may include a superconducting bucket or aluminum coil as the payload. The coils of a mass driver can induce
81:, or another body. A small mass driver could act as a rocket engine on board a spacecraft, flinging pieces of material into space to propel itself. Another variation would have a massive facility on a moon or asteroid send projectiles to assist a distant craft.
740:
considered necessary for a lunar surface mass driver. The mass driver was demonstrated several times during breaks between conference sessions, each time with a round of applause for the team who built it in less than four months on a budget of $ 2,000.
403:
One possible drawback of the mass driver is that it has the potential to send solid reaction mass travelling at dangerously high relative speeds into useful orbits and traffic lanes. To overcome this problem, most schemes plan to throw finely-divided
432:, 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
804:
Mass Driver Two combines for the first time all the essential features of an operational mass driver, with the exception of bucket recirculation and payload handling. Its nominal design acceleration is 5000 m/s2, for a final velocity of 112
483:
One of the first engineering descriptions of an "Electric Gun" appears in the technical supplement of the 1937 science fiction novel "Zero to Eighty" by "Akkad
Pseudoman", a pen name for the Princeton physicist and electrical entrepreneur
762:
841:
187:
any other celestial body without a significant atmosphere) then a reusable bucket's acceleration would not be limited by the length of the track – however, such a system would need to be engineered to withstand substantial
218:
Natural elevations, such as mountains, may facilitate the construction of the distant, upwardly targeted part. The higher up the track terminates, the less resistance from the atmosphere the launched object will encounter.
317:) the spaceship could then use the mass driver to accelerate pieces of matter of almost any sort, boosting itself in the opposite direction. At the smallest scale of reaction mass, this type of drive is called an
73:
that magnetically accelerates a package consisting of a magnetizable holder containing a payload. Once the payload has been accelerated, the two separate, and the holder is slowed and recycled for another payload.
242:, though total costs would be far more than electricity alone. By being mainly located slightly above, on or beneath the ground, a mass driver may be easier to maintain compared with many other structures of
111:
costs tend to be accordingly low, initial development and construction costs are highly dependent on performance, especially the intended mass, acceleration, and velocity of projectiles. For instance, while
399:
Since a mass driver could use any type of mass for reaction mass to move the spacecraft, a mass driver or some variation seems ideal for deep-space vehicles that scavenge reaction mass from found resources.
294:(spiral). Another concept involves a large ring design whereby a space vehicle would circle the ring numerous times, gradually gaining speed, before being released into a launch corridor leading skyward.
816:
58:, though a rotary mass driver has also been proposed. Sequential firing of a row of electromagnets accelerates the payload along a path. After leaving the path, the payload continues to move due to
789:
455:
Small to moderate size high-acceleration electromagnetic projectile launchers are currently undergoing active research by the US Navy for use as ground-based or ship-based weapons (most often
159:
greatly reduce the required velocity to reach lunar orbit; also, lunar launches from a fixed position are much less likely to generate issues with respect to matters such as traffic control.
324:
No absolute theoretical limit is known for the size, acceleration or muzzle energy of linear motors. However, practical engineering constraints apply for such as the power-to-mass ratio,
203:
concepts, a mass driver could be any length, affordable, and with relatively smooth acceleration throughout, optionally even lengthy enough to reach target velocity without excessive
335:
for any thruster constrained by a limited amount of onboard spacecraft power. Thrust and momentum from exhaust, per unit mass expelled, scales up linearly with its velocity (
1397:
475:). As the mass driver would be located further up the gravity well than the theoretical targets, it would enjoy a significant energy imbalance in terms of counter-attack.
1028:
872:
1101:
Park, Chul; Boden, Stuart W. (1982). "Ablation and deceleration of mass-driver launched projectiles for space disposal of nuclear wastes". In Horton, T. E. (ed.).
301:
would escape the Solar System, with atmospheric passage at such speed calculated as survivable through an elongated projectile and a very substantial heatshield.
408:. Alternatively, liquid oxygen could be used as reaction mass, which upon release would boil down to its molecular state. Propelling the reaction mass to solar
463:
in some cases). On larger scale than weapons currently near deployment but sometimes suggested in long-range future projections, a sufficiently high velocity
1274:
1076:
238:
per kilogram if efficiencies are relatively high, which accordingly has been hypothesized to be under $ 1 of electrical energy cost per kilogram shipped to
281:
To launch a space vehicle with humans on board, a mass driver's track would need to be almost 1000 kilometres long if providing almost all the velocity to
1106:
266:
if a design prioritizes minimizing such, but hybrid proposals optionally reduce requirements for the mass driver itself by having a greater portion of
77:
Mass drivers can be used to propel spacecraft in three different ways: A large, ground-based mass driver could launch spacecraft away from Earth, the
179:
Based on this mode, a major proposal for the use of mass drivers involved transporting lunar-surface material to space habitats for processing using
1437:
993:
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1780:
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2613:
2176:
2294:
285:, though a lesser length could provide major launch assist. Required length, if accelerating mainly at near a constant maximum acceptable
1915:
262:
needed to be provided by rockets to reach orbit. Well under a tenth of orbital velocity from a small rocket thruster is enough to raise
709:
661:
363:
901:
1404:
1358:
2192:
424:
could be used to "reflect" masses from a stationary mass driver. Each deceleration and acceleration of the mass contributes to the
1325:
2680:
552:
1122:
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propelled magsail). A similar system could also deliver pellets of fuel to a spacecraft to power another propulsion system.
1387:
328:
dissipation, and the energy intake able to be supplied and handled. Exhaust velocity is best neither too low nor too high.
2857:
1430:
2769:
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1035:
876:
297:
Mass drivers have been proposed for the disposal of nuclear waste in space: a projectile launched at much above Earth's
2097:
2171:
1251:
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1746:
1423:
1080:
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methods like mass drivers are systems where energy does not come from the propellant itself. (Such contrasts to
1278:
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2197:
2062:
1766:
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828:
51:
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in a similar manner as classic firearms or cannon using chemical combustion. Hybrids between coilguns and
2862:
313:
could carry a mass driver as its primary engine. With a suitable source of electrical power (probably a
54:
up to high speeds. Existing and proposed mass drivers use coils of wire energized by electricity to make
1010:
2801:
2737:
1700:
1160:
990:
1323:
QDR 2001: Strategy-Driven
Choices for America's Security, Chapter 11, Global Reach/Global Power School
2852:
2784:
2744:
2256:
2115:
230:
of projectiles launched at up to 9000 m/s velocity (if including extra for drag losses) towards
932:"StarTram2010: Maglev Launch: Ultra Low Cost Ultra High Volume Access to Space for Cargo and Humans"
2646:
2603:
2598:
2506:
2289:
2048:
2022:
1964:
1948:
1938:
1509:
842:"High Current, High Voltage Solid State Discharge Switches for Electromagnetic Launch Applications"
513:, a company founded in 2014, conducted the initial test of their test accelerator in October 2021.
271:
211:
for spacelaunch, targeted upwards at the end, partly by bending of the track upwards and partly by
2221:
447:, a system in which a continuous stream of pellets in a circular track holds up a tall structure.
2749:
2722:
2583:
2565:
2345:
2318:
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2007:
1969:
1943:
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472:
339:= mv), yet kinetic energy and energy input requirements scale up faster with velocity squared (
243:
156:
39:
1239:
650:
356:
mv). Too low an exhaust velocity would excessively increase propellant mass needed under the
2685:
2575:
2491:
1981:
1974:
1789:
1733:
724:
607:
392:
during the mission profile (as possible with some thruster types, including mass drivers and
380:
a row of spotlights, photons being an example of an extremely low momentum to energy ratio).
371:
1298:
467:, a mass driver, could in theory be used as intercontinental artillery (or, if built on the
2732:
2695:
2675:
2092:
2087:
1991:
1905:
1310:
1062:
965:
905:
773:
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389:
376:
332:
212:
112:
8:
2789:
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2251:
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2017:
1986:
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969:
777:
2806:
2450:
2416:
2381:
1728:
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530:
388:
if operating at constant specific impulse, except greater optimization could come from
143:
measures would be needed to ensure the safety of other aircraft operating in the area.
19:
1322:
1114:
2445:
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2366:
2266:
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1247:
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686:
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for passengers. It can be constructed as a very long and mainly horizontally aligned
188:
183:. The Space Studies Institute showed that this application was reasonably practical.
69:
payload is technically a mass driver, in this context a mass driver is essentially a
191:
if it were intended to accelerate passengers and/or cargo to very high velocities.
2774:
2690:
2593:
2431:
2421:
2371:
2077:
1830:
1679:
1167:
1110:
973:
956:
Kolm, H.; Mongeau, P.; Williams, F. (September 1980). "Electromagnetic
Launchers".
781:
176:
increasing distances to give a fixed amount of velocity increase per unit of time.
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2012:
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Affordable
Spacecraft: Design and Launch Alternatives, Chapter 5, Page 36
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247:
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1201:
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510:
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Another theoretical use for this concept of propulsion can be found in
421:
325:
310:
254:, such as with a mechanical shutter kept closed most of the time but a
246:. Whether or not underground, it needs to be housed in a pipe that is
136:
130:
Earth-based mass drivers for propelling vehicles to orbit, such as the
115:
built his first mass driver in 1976–1977 with a $ 2000 budget, a short
66:
538:
500:
85:
2700:
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318:
223:
200:
105:
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of the spacecraft. The lightweight, fast spacecraft need not carry
1607:
1359:"Alternative rocket builder SpinLaunch completes first test flight"
592:
425:
336:
131:
59:
1539:
1145:
331:
There is a mission-dependent limited optimal exhaust velocity and
274:). On Earth, a mass-driver design could possibly use well-tested
2202:
1835:
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572:
557:
460:
456:
385:
286:
267:
263:
204:
152:
120:
89:
70:
1226:
U.S. Patent #5305974, Spacecraft
Propulsion by Momentum Transfer
1146:"Physics of Rocket Systems with Separated Energy and Propellant"
1825:
1803:
1161:
Interstellar
Propulsion Using a Pellet Stream for Mass Transfer
504:
393:
1299:
Applications of coilgun electromagnetic propulsion technology
291:
258:
used during the moments of firing to prevent loss of vacuum.
167:
in a payload's aluminum coil, and then act on the resulting
468:
412:
is another way to ensure that it will not remain a hazard.
405:
148:
78:
24:
1077:"Magnets, Not Rockets, Could Fling Satellites Into Space"
752:
491:
Later prototype mass drivers have been built since 1976 (
859:"Pulse Power Switching Devices – An Overview"
1244:
Deep Space Probes: To The Outer Solar System and Beyond
687:"Electromagnetic Guns, Launchers, and Reaction Engines"
171:. There are two sections of a mass driver. The maximum
499:
in order to prove their properties and practicality.
1394:—a page describing research into linear motors at MIT
1346:. Princeton, New Jersey: Princeton University Press.
520:
1405:"Huge 'launch ring' to fling satellites into orbit"
955:
1202:"Interstellar Flight Using Near-Term Technologies"
1107:American Institute of Aeronautics and Astronautics
817:IEEE Transactions on Magnetics, Vol Mag-18, No. 1
147:proposals feature installing mass drivers on the
2844:
1219:
829:Electromagnetic Launchers for Space Applications
710:"1977 Space Manufacturing Facilities Conference"
304:
394:variable specific impulse magnetoplasma rockets
873:"Scanning the Technology: Modern Pulsed Power"
2476:
1774:
1431:
991:NASA, 1975: Space Settlements: A Design Study
700:
23:Artist's conception of a mass driver on the
926:
924:
922:
2825:
2483:
2469:
1781:
1767:
1445:
1438:
1424:
1152:
1140:
1138:
1136:
1134:
1057:
1055:
810:
450:
375:range up to where mass drivers merge into
119:firing a projectile at 40 m/s and 33
2490:
1788:
1341:
1100:
896:
894:
2193:Atmosphere-breathing electric propulsion
1398:Electromagnetic Launch of Lunar Material
919:
902:"L5 news, Sept 1980: Mass Driver Update"
684:
18:
1237:
1199:
1131:
1052:
819:, January 1982. Retrieved May 10, 2011.
648:
139:such launches would cause, significant
2845:
2681:Differential technological development
1356:
1158:
891:
553:Electromagnetic Aircraft Launch System
415:
84:Miniaturized mass drivers can also be
2464:
1762:
1419:
1402:
651:"ASTEROID RETRIEVAL BY ROTARY ROCKET"
478:
99:
65:Although any device used to propel a
473:attack a location on Earth's surface
2770:Future-oriented technology analysis
723:(6). L-5 Society: 4. Archived from
436:(a macroscopic-scale analogue of a
199:In contrast to cargo-only chemical
13:
2098:Field-emission electric propulsion
1103:Thermophysics of Atmospheric Entry
763:"Mass Driver Two: A Status Report"
14:
2884:
2172:Microwave electrothermal thruster
1378:
1115:10.2514/5.9781600865565.0201.0225
250:in order to prevent internal air
2824:
2444:
1741:
1740:
1538:
1200:Gilster, Paul (April 20, 2005).
537:
523:
495:), some constructed by the U.S.
1403:Shiga, David (3 October 2006).
1350:
1335:
1316:
1304:
1292:
1267:
1231:
1193:
1181:from the original on 2022-10-09
1094:
1069:
1021:
1003:
984:
949:
667:from the original on 2022-10-09
2302:Pulsed nuclear thermal rocket
2198:High Power Electric Propulsion
1357:Sheetz, Michael (2021-11-09).
958:IEEE Transactions on Magnetics
865:
851:
834:
822:
770:IEEE Transactions on Magnetics
745:
693:
685:Kolm, H.; et al. (1980).
678:
642:
1:
2797:Technology in science fiction
2157:Helicon double-layer thruster
2126:Electrodeless plasma thruster
2121:Magnetoplasmadynamic thruster
636:
305:Spacecraft-based mass drivers
270:by a rocket burn (or orbital
2642:Laser communication in space
1482:Pneumatic freestanding tower
1238:Matloff, Gregory L. (2005).
501:Military R&D on coilguns
7:
2858:Magnetic propulsion devices
1029:"Advanced Propulsion Study"
516:
194:
16:Proposed spacelaunch method
10:
2891:
2802:Technology readiness level
2738:Technological unemployment
1240:"8.5: A Toroidal Ramscoop"
649:Pearson, J. (1980-01-16).
103:
2820:
2785:Technological singularity
2745:Technological convergence
2663:
2629:
2574:
2514:
2505:
2498:
2442:
2359:
2338:
2282:
2229:
2220:
2185:
2139:
2116:Pulsed inductive thruster
2108:
2070:
2061:
2031:
2000:
1957:
1931:
1924:
1861:
1796:
1719:
1693:
1662:
1642:
1616:
1585:
1578:
1547:
1536:
1518:
1497:
1490:
1469:
1462:
1453:
1342:Pseudoman, Akkad (1937).
1246:. Springer. p. 120.
978:10.1109/TMAG.1980.1060806
831:. Retrieved May 10, 2011.
786:10.1109/tmag.1982.1061777
622:and the Maglifter project
613:
2647:Orbital propellant depot
2604:Plasma propulsion engine
2599:Nuclear pulse propulsion
2290:Nuclear pulse propulsion
2049:Electric-pump-fed engine
1949:Hybrid-propellant rocket
1939:Liquid-propellant rocket
1510:Momentum exchange tether
1332:. Retrieved May 9, 2011.
1313:. Retrieved May 9, 2011.
1301:. Retrieved May 9, 2011.
1228:. Retrieved May 9, 2011.
1011:"Magnetic Launch System"
390:varying exhaust velocity
272:momentum exchange tether
215:in the other direction.
38:is a proposed method of
36:electromagnetic catapult
2750:Technological evolution
2723:Exploratory engineering
2584:Beam-powered propulsion
2566:Reusable launch vehicle
2346:Beam-powered propulsion
2319:Fission-fragment rocket
2274:Nuclear photonic rocket
2242:Nuclear electric rocket
2008:Staged combustion cycle
1944:Solid-propellant rocket
1685:Beam-powered propulsion
1570:Endo-atmospheric tether
1063:"Constant Acceleration"
1000:. Retrieved 2011-05-09.
497:Space Studies Institute
451:Mass drivers as weapons
434:beam-powered propulsion
2873:Non-rocket spacelaunch
2760:Technology forecasting
2755:Technological paradigm
2728:Proactionary principle
2529:Non-rocket spacelaunch
2397:Non-rocket spacelaunch
2247:Nuclear thermal rocket
2147:Pulsed plasma thruster
1711:High-altitude platform
1629:Blast wave accelerator
1447:Non-rocket spacelaunch
244:non-rocket spacelaunch
40:non-rocket spacelaunch
27:
2868:Spacecraft propulsion
2686:Disruptive innovation
2492:Emerging technologies
2063:Electrical propulsion
1790:Spacecraft propulsion
1734:Megascale engineering
1159:Singer, C.E. (1979).
608:Spacecraft propulsion
471:or in orbit, used to
377:particle accelerators
372:propulsive efficiency
226:per kilogram or less
22:
2733:Technological change
2676:Collingridge dilemma
2295:Antimatter-catalyzed
2093:Hall-effect thruster
1906:Solar thermal rocket
1579:Projectile launchers
1385:Electromagnetic Guns
1109:. pp. 201–225.
486:Edwin Fitch Northrup
2790:Technology scouting
2765:Accelerating change
2637:Interstellar travel
2237:Direct Fusion Drive
2152:Vacuum arc thruster
2039:Pressure-fed engine
2018:Gas-generator cycle
1925:Chemical propulsion
1862:Physical propulsion
970:1980ITM....16..719K
879:on December 1, 2012
778:1982ITM....18..127S
772:. Mag-18 (1): 127.
503:is related, as are
420:A mass driver on a
416:Hybrid mass drivers
364:Electric propulsion
141:air traffic control
96:are also possible.
2863:Space colonization
2807:Technology roadmap
2451:Spaceflight portal
2417:Reactionless drive
2382:Aerogravity assist
2222:Nuclear propulsion
1729:Rocket sled launch
1706:Buoyant space port
1548:Dynamic structures
1390:2008-05-16 at the
1328:2012-03-23 at the
996:2017-06-25 at the
757:; Kubby, Joel A.;
753:Snow, William R.;
531:Spaceflight portal
479:Practical attempts
189:centrifugal forces
157:lack of atmosphere
100:Fixed mass drivers
42:which would use a
28:
2840:
2839:
2659:
2658:
2655:
2654:
2458:
2457:
2412:Atmospheric entry
2367:Orbital mechanics
2334:
2333:
2216:
2215:
2167:Resistojet rocket
2057:
2056:
2032:Intake mechanisms
1965:Liquid propellant
1869:Cold gas thruster
1756:
1755:
1658:
1657:
1534:
1533:
1530:
1529:
1498:Orbiting skyhooks
1463:Static structures
1124:978-0-915928-66-8
1015:The Space Monitor
759:O'Nell, Gerard K.
626:Gerard K. O'Neill
384:of total mission
213:Earth's curvature
2880:
2853:Magnetic devices
2828:
2827:
2775:Horizon scanning
2691:Ephemeralization
2609:Helicon thruster
2594:Laser propulsion
2512:
2511:
2503:
2502:
2485:
2478:
2471:
2462:
2461:
2448:
2432:Alcubierre drive
2422:Field propulsion
2372:Orbital maneuver
2360:Related concepts
2227:
2226:
2078:Colloid thruster
2068:
2067:
1929:
1928:
1831:Specific impulse
1783:
1776:
1769:
1760:
1759:
1744:
1743:
1725:
1680:Laser propulsion
1583:
1582:
1542:
1495:
1494:
1467:
1466:
1440:
1433:
1426:
1417:
1416:
1412:
1373:
1372:
1370:
1369:
1354:
1348:
1347:
1339:
1333:
1320:
1314:
1308:
1302:
1296:
1290:
1289:
1287:
1286:
1277:. Archived from
1271:
1265:
1264:
1262:
1260:
1235:
1229:
1223:
1217:
1216:
1214:
1212:
1197:
1191:
1190:
1188:
1186:
1180:
1165:
1156:
1150:
1149:
1142:
1129:
1128:
1098:
1092:
1091:
1089:
1088:
1079:. Archived from
1073:
1067:
1066:
1059:
1050:
1049:
1047:
1046:
1040:
1034:. Archived from
1033:
1025:
1019:
1018:
1007:
1001:
988:
982:
981:
953:
947:
946:
944:
943:
934:. Archived from
928:
917:
916:
914:
913:
904:. Archived from
898:
889:
888:
886:
884:
875:. Archived from
869:
863:
862:
855:
849:
848:
846:
838:
832:
826:
820:
814:
808:
807:
801:
800:
794:
788:. Archived from
767:
761:(January 1982).
755:Dunbar, R. Scott
749:
743:
742:
736:
735:
729:
714:
697:
691:
690:
682:
676:
675:
673:
672:
666:
655:
646:
547:
542:
541:
533:
528:
527:
526:
368:chemical rockets
355:
354:
350:
347:
333:specific impulse
151:where the lower
94:helical railguns
2890:
2889:
2883:
2882:
2881:
2879:
2878:
2877:
2843:
2842:
2841:
2836:
2816:
2651:
2625:
2570:
2494:
2489:
2459:
2454:
2438:
2355:
2330:
2278:
2212:
2181:
2135:
2109:Electromagnetic
2104:
2053:
2044:Pump-fed engine
2027:
1996:
1953:
1920:
1857:
1848:Rocket equation
1814:Reaction engine
1792:
1787:
1757:
1752:
1723:
1715:
1694:Buoyant lifting
1689:
1663:Reaction drives
1654:
1638:
1634:Ram accelerator
1612:
1574:
1543:
1526:
1519:Space elevators
1514:
1486:
1458:
1449:
1444:
1392:Wayback Machine
1381:
1376:
1367:
1365:
1355:
1351:
1340:
1336:
1330:Wayback Machine
1321:
1317:
1309:
1305:
1297:
1293:
1284:
1282:
1273:
1272:
1268:
1258:
1256:
1254:
1236:
1232:
1224:
1220:
1210:
1208:
1206:Centauri Dreams
1198:
1194:
1184:
1182:
1178:
1172:10.2172/5770056
1163:
1157:
1153:
1144:
1143:
1132:
1125:
1099:
1095:
1086:
1084:
1075:
1074:
1070:
1061:
1060:
1053:
1044:
1042:
1038:
1031:
1027:
1026:
1022:
1009:
1008:
1004:
998:Wayback Machine
989:
985:
954:
950:
941:
939:
930:
929:
920:
911:
909:
900:
899:
892:
882:
880:
871:
870:
866:
857:
856:
852:
844:
840:
839:
835:
827:
823:
815:
811:
798:
796:
792:
765:
750:
746:
733:
731:
727:
712:
706:Henson, Carolyn
698:
694:
683:
679:
670:
668:
664:
653:
647:
643:
639:
620:Eric Laithwaite
616:
578:Ram accelerator
568:Helical railgun
543:
536:
529:
524:
522:
519:
481:
453:
445:space fountains
418:
410:escape velocity
358:rocket equation
352:
348:
345:
344:
315:nuclear reactor
307:
299:escape velocity
283:Low Earth Orbit
232:low Earth orbit
197:
108:
102:
86:used as weapons
17:
12:
11:
5:
2888:
2887:
2876:
2875:
2870:
2865:
2860:
2855:
2838:
2837:
2835:
2834:
2821:
2818:
2817:
2815:
2814:
2809:
2804:
2799:
2794:
2793:
2792:
2787:
2782:
2777:
2772:
2767:
2757:
2752:
2747:
2742:
2741:
2740:
2730:
2725:
2720:
2719:
2718:
2713:
2708:
2703:
2693:
2688:
2683:
2678:
2673:
2667:
2665:
2661:
2660:
2657:
2656:
2653:
2652:
2650:
2649:
2644:
2639:
2633:
2631:
2627:
2626:
2624:
2623:
2618:
2617:
2616:
2611:
2601:
2596:
2591:
2586:
2580:
2578:
2572:
2571:
2569:
2568:
2563:
2562:
2561:
2556:
2554:Space fountain
2551:
2549:Space elevator
2546:
2541:
2536:
2526:
2520:
2518:
2509:
2500:
2496:
2495:
2488:
2487:
2480:
2473:
2465:
2456:
2455:
2443:
2440:
2439:
2437:
2436:
2435:
2434:
2429:
2419:
2414:
2409:
2404:
2399:
2394:
2389:
2384:
2379:
2377:Gravity assist
2374:
2369:
2363:
2361:
2357:
2356:
2354:
2353:
2348:
2342:
2340:
2339:External power
2336:
2335:
2332:
2331:
2329:
2328:
2327:
2326:
2316:
2315:
2314:
2312:Bussard ramjet
2304:
2299:
2298:
2297:
2286:
2284:
2280:
2279:
2277:
2276:
2271:
2270:
2269:
2264:
2259:
2254:
2244:
2239:
2233:
2231:
2224:
2218:
2217:
2214:
2213:
2211:
2210:
2205:
2200:
2195:
2189:
2187:
2183:
2182:
2180:
2179:
2174:
2169:
2164:
2159:
2154:
2149:
2143:
2141:
2140:Electrothermal
2137:
2136:
2134:
2133:
2128:
2123:
2118:
2112:
2110:
2106:
2105:
2103:
2102:
2101:
2100:
2095:
2090:
2080:
2074:
2072:
2065:
2059:
2058:
2055:
2054:
2052:
2051:
2046:
2041:
2035:
2033:
2029:
2028:
2026:
2025:
2020:
2015:
2013:Expander cycle
2010:
2004:
2002:
1998:
1997:
1995:
1994:
1989:
1984:
1982:Monopropellant
1979:
1978:
1977:
1972:
1961:
1959:
1955:
1954:
1952:
1951:
1946:
1941:
1935:
1933:
1926:
1922:
1921:
1919:
1918:
1913:
1908:
1903:
1898:
1893:
1892:
1891:
1881:
1876:
1871:
1865:
1863:
1859:
1858:
1856:
1855:
1853:Thermal rocket
1850:
1845:
1840:
1839:
1838:
1833:
1823:
1822:
1821:
1816:
1806:
1800:
1798:
1794:
1793:
1786:
1785:
1778:
1771:
1763:
1754:
1753:
1751:
1750:
1737:
1736:
1731:
1726:
1720:
1717:
1716:
1714:
1713:
1708:
1703:
1697:
1695:
1691:
1690:
1688:
1687:
1682:
1677:
1672:
1666:
1664:
1660:
1659:
1656:
1655:
1653:
1652:
1646:
1644:
1640:
1639:
1637:
1636:
1631:
1626:
1620:
1618:
1614:
1613:
1611:
1610:
1605:
1600:
1595:
1589:
1587:
1580:
1576:
1575:
1573:
1572:
1567:
1562:
1557:
1555:Space fountain
1551:
1549:
1545:
1544:
1537:
1535:
1532:
1531:
1528:
1527:
1524:Space elevator
1522:
1520:
1516:
1515:
1513:
1512:
1507:
1501:
1499:
1492:
1488:
1487:
1485:
1484:
1479:
1473:
1471:
1464:
1460:
1459:
1454:
1451:
1450:
1443:
1442:
1435:
1428:
1420:
1414:
1413:
1400:
1395:
1380:
1379:External links
1377:
1375:
1374:
1349:
1344:Zero to Eighty
1334:
1315:
1303:
1291:
1266:
1252:
1230:
1218:
1192:
1151:
1130:
1123:
1093:
1068:
1051:
1020:
1002:
983:
964:(5): 719–721.
948:
918:
890:
864:
850:
833:
821:
809:
744:
692:
677:
640:
638:
635:
634:
633:
628:
623:
615:
612:
611:
610:
605:
603:Space fountain
600:
595:
590:
585:
580:
575:
570:
565:
563:Plasma railgun
560:
555:
549:
548:
545:Science portal
534:
518:
515:
480:
477:
452:
449:
417:
414:
341:kinetic energy
306:
303:
236:kilowatt-hours
228:kinetic energy
196:
193:
169:magnetic field
113:Gerard O'Neill
101:
98:
56:electromagnets
15:
9:
6:
4:
3:
2:
2886:
2885:
2874:
2871:
2869:
2866:
2864:
2861:
2859:
2856:
2854:
2851:
2850:
2848:
2833:
2832:
2823:
2822:
2819:
2813:
2812:Transhumanism
2810:
2808:
2805:
2803:
2800:
2798:
2795:
2791:
2788:
2786:
2783:
2781:
2778:
2776:
2773:
2771:
2768:
2766:
2763:
2762:
2761:
2758:
2756:
2753:
2751:
2748:
2746:
2743:
2739:
2736:
2735:
2734:
2731:
2729:
2726:
2724:
2721:
2717:
2714:
2712:
2709:
2707:
2704:
2702:
2699:
2698:
2697:
2694:
2692:
2689:
2687:
2684:
2682:
2679:
2677:
2674:
2672:
2669:
2668:
2666:
2662:
2648:
2645:
2643:
2640:
2638:
2635:
2634:
2632:
2628:
2622:
2619:
2615:
2612:
2610:
2607:
2606:
2605:
2602:
2600:
2597:
2595:
2592:
2590:
2587:
2585:
2582:
2581:
2579:
2577:
2573:
2567:
2564:
2560:
2557:
2555:
2552:
2550:
2547:
2545:
2542:
2540:
2537:
2535:
2532:
2531:
2530:
2527:
2525:
2524:Fusion rocket
2522:
2521:
2519:
2517:
2513:
2510:
2508:
2507:Space science
2504:
2501:
2497:
2493:
2486:
2481:
2479:
2474:
2472:
2467:
2466:
2463:
2453:
2452:
2447:
2441:
2433:
2430:
2428:
2425:
2424:
2423:
2420:
2418:
2415:
2413:
2410:
2408:
2405:
2403:
2400:
2398:
2395:
2393:
2390:
2388:
2387:Oberth effect
2385:
2383:
2380:
2378:
2375:
2373:
2370:
2368:
2365:
2364:
2362:
2358:
2352:
2349:
2347:
2344:
2343:
2341:
2337:
2325:
2322:
2321:
2320:
2317:
2313:
2310:
2309:
2308:
2307:Fusion rocket
2305:
2303:
2300:
2296:
2293:
2292:
2291:
2288:
2287:
2285:
2281:
2275:
2272:
2268:
2265:
2263:
2260:
2258:
2255:
2253:
2250:
2249:
2248:
2245:
2243:
2240:
2238:
2235:
2234:
2232:
2230:Closed system
2228:
2225:
2223:
2219:
2209:
2206:
2204:
2201:
2199:
2196:
2194:
2191:
2190:
2188:
2184:
2178:
2175:
2173:
2170:
2168:
2165:
2163:
2162:Arcjet rocket
2160:
2158:
2155:
2153:
2150:
2148:
2145:
2144:
2142:
2138:
2132:
2131:Plasma magnet
2129:
2127:
2124:
2122:
2119:
2117:
2114:
2113:
2111:
2107:
2099:
2096:
2094:
2091:
2089:
2086:
2085:
2084:
2081:
2079:
2076:
2075:
2073:
2071:Electrostatic
2069:
2066:
2064:
2060:
2050:
2047:
2045:
2042:
2040:
2037:
2036:
2034:
2030:
2024:
2023:Tap-off cycle
2021:
2019:
2016:
2014:
2011:
2009:
2006:
2005:
2003:
1999:
1993:
1992:Tripropellant
1990:
1988:
1985:
1983:
1980:
1976:
1973:
1971:
1968:
1967:
1966:
1963:
1962:
1960:
1956:
1950:
1947:
1945:
1942:
1940:
1937:
1936:
1934:
1930:
1927:
1923:
1917:
1914:
1912:
1911:Photon rocket
1909:
1907:
1904:
1902:
1901:Magnetic sail
1899:
1897:
1896:Electric sail
1894:
1890:
1887:
1886:
1885:
1882:
1880:
1877:
1875:
1872:
1870:
1867:
1866:
1864:
1860:
1854:
1851:
1849:
1846:
1844:
1841:
1837:
1834:
1832:
1829:
1828:
1827:
1824:
1820:
1819:Reaction mass
1817:
1815:
1812:
1811:
1810:
1809:Rocket engine
1807:
1805:
1802:
1801:
1799:
1795:
1791:
1784:
1779:
1777:
1772:
1770:
1765:
1764:
1761:
1749:
1748:
1739:
1738:
1735:
1732:
1730:
1727:
1722:
1721:
1718:
1712:
1709:
1707:
1704:
1702:
1699:
1698:
1696:
1692:
1686:
1683:
1681:
1678:
1676:
1673:
1671:
1668:
1667:
1665:
1661:
1651:
1648:
1647:
1645:
1641:
1635:
1632:
1630:
1627:
1625:
1622:
1621:
1619:
1615:
1609:
1606:
1604:
1601:
1599:
1596:
1594:
1591:
1590:
1588:
1584:
1581:
1577:
1571:
1568:
1566:
1563:
1561:
1558:
1556:
1553:
1552:
1550:
1546:
1541:
1525:
1521:
1517:
1511:
1508:
1506:
1503:
1502:
1500:
1496:
1493:
1489:
1483:
1480:
1478:
1475:
1474:
1472:
1468:
1465:
1461:
1457:
1452:
1448:
1441:
1436:
1434:
1429:
1427:
1422:
1421:
1418:
1410:
1409:New Scientist
1406:
1401:
1399:
1396:
1393:
1389:
1386:
1383:
1382:
1364:
1360:
1353:
1345:
1338:
1331:
1327:
1324:
1319:
1312:
1307:
1300:
1295:
1281:on 2017-11-08
1280:
1276:
1270:
1255:
1253:9783540247722
1249:
1245:
1241:
1234:
1227:
1222:
1207:
1203:
1196:
1177:
1173:
1169:
1162:
1155:
1147:
1141:
1139:
1137:
1135:
1126:
1120:
1116:
1112:
1108:
1104:
1097:
1083:on 2017-12-01
1082:
1078:
1072:
1064:
1058:
1056:
1041:on 2012-12-01
1037:
1030:
1024:
1016:
1012:
1006:
999:
995:
992:
987:
979:
975:
971:
967:
963:
959:
952:
938:on 2017-07-27
937:
933:
927:
925:
923:
908:on 2017-12-01
907:
903:
897:
895:
878:
874:
868:
860:
854:
843:
837:
830:
825:
818:
813:
806:
795:on 2012-07-22
791:
787:
783:
779:
775:
771:
764:
760:
756:
748:
741:
730:on 2017-05-05
726:
722:
718:
711:
708:(June 1977).
707:
703:
702:Henson, Keith
696:
688:
681:
663:
659:
652:
645:
641:
632:
629:
627:
624:
621:
618:
617:
609:
606:
604:
601:
599:
596:
594:
591:
589:
586:
584:
583:Light-gas gun
581:
579:
576:
574:
571:
569:
566:
564:
561:
559:
556:
554:
551:
550:
546:
540:
535:
532:
521:
514:
512:
508:
506:
505:maglev trains
502:
498:
494:
493:Mass Driver 1
489:
487:
476:
474:
470:
466:
462:
458:
448:
446:
441:
439:
438:particle beam
435:
431:
430:reaction mass
427:
423:
413:
411:
407:
401:
397:
395:
391:
387:
381:
378:
373:
369:
365:
361:
359:
342:
338:
334:
329:
327:
322:
320:
316:
312:
302:
300:
295:
293:
288:
284:
279:
277:
273:
269:
265:
259:
257:
256:plasma window
253:
249:
248:vacuum pumped
245:
241:
237:
233:
229:
225:
220:
216:
214:
210:
206:
202:
192:
190:
184:
182:
177:
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2589:Ion thruster
2559:Space tether
2539:Orbital ring
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2392:Space launch
2324:Fission sail
2252:Radioisotope
2207:
2083:Ion thruster
2001:Power cycles
1987:Bipropellant
1879:Steam rocket
1874:Water rocket
1745:
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1560:Orbital ring
1408:
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2780:Moore's law
2711:Neuroethics
2706:Cyberethics
2534:Mass driver
2407:Aerocapture
2402:Aerobraking
2283:Open system
2267:"Lightbulb"
2208:Mass driver
1958:Propellants
1889:Diffractive
1675:Spaceplanes
1598:Mass driver
1565:Launch loop
1477:Space tower
1470:Compressive
1456:Spaceflight
1275:"U.S. Navy"
598:Launch loop
32:mass driver
2847:Categories
2671:Automation
2621:Solar sail
2576:Propulsion
2427:Warp drive
2257:Salt-water
1975:Hypergolic
1884:Solar sail
1670:Air launch
1650:Slingatron
1643:Mechanical
1586:Electrical
1368:2021-11-11
1285:2013-06-11
1166:(Report).
1087:2008-05-04
1045:2011-05-03
942:2011-04-28
912:2009-07-28
799:2017-11-26
734:2017-11-27
671:2021-10-18
637:References
631:Henry Kolm
511:SpinLaunch
422:spacecraft
326:waste heat
311:spacecraft
224:megajoules
137:turbulence
117:test model
104:See also:
48:accelerate
2701:Bioethics
1970:Cryogenic
1624:Space gun
883:April 27,
751:Compare:
699:Compare:
319:ion drive
234:is a few
201:space-gun
106:Space gun
67:ballistic
2262:Gas core
1797:Concepts
1747:Category
1724:See also
1617:Chemical
1608:StarTram
1388:Archived
1326:Archived
1176:Archived
994:Archived
662:Archived
593:StarTram
517:See also
461:coilguns
457:railguns
426:momentum
337:momentum
205:g forces
195:On Earth
132:StarTram
92:such as
90:railguns
60:momentum
52:payloads
2544:Skyhook
2351:Tethers
2203:MagBeam
2088:Gridded
1843:Staging
1836:Delta-v
1701:Balloon
1603:Railgun
1593:Coilgun
1505:Skyhook
1491:Tensile
966:Bibcode
774:Bibcode
717:L5 News
573:Coilgun
558:Railgun
386:delta v
351:⁄
292:helical
287:g-force
268:delta-v
264:perigee
222:The 40
153:gravity
71:coilgun
2696:Ethics
2664:Topics
2614:VASIMR
2516:Launch
2499:Fields
2177:VASIMR
1826:Thrust
1804:Rocket
1259:May 9,
1250:
1211:May 9,
1185:May 9,
1121:
689:. MIT.
614:People
370:where
276:maglev
2630:Other
2186:Other
1932:State
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654:(PDF)
2831:List
1916:WINE
1363:CNBC
1261:2011
1248:ISBN
1213:2011
1187:2011
1119:ISBN
885:2011
805:m/s.
658:AIAA
469:Moon
459:but
406:dust
252:drag
155:and
149:Moon
79:Moon
25:Moon
1168:doi
1111:doi
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240:LEO
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