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Sunday, December 15, 2019

Nuclear pulse propulsion

From Wikipedia, the free encyclopedia
 
An artist's conception of the Project Orion "basic" spacecraft, powered by nuclear pulse propulsion.
 
Nuclear pulse propulsion or external pulsed plasma propulsion is a hypothetical method of spacecraft propulsion that uses nuclear explosions for thrust. It was first developed as Project Orion by DARPA, after a suggestion by Stanislaw Ulam in 1947. Newer designs using inertial confinement fusion have been the baseline for most post-Orion designs, including Project Daedalus and Project Longshot

Project Orion

A nuclear pulse propulsion unit. The explosive charge ablatively vaporizes the propellant, propelling it away from the charge, and simultaneously creating a plasma out of the propellant. The propellant then goes on to impact the pusher plate at the bottom of the Orion spacecraft, imparting a pulse of 'pushing' energy.
 
Project Orion was the first serious attempt to design a nuclear pulse rocket. The design effort was carried out at General Atomics in the late 1950s and early 1960s. The idea of Orion was to react small directional nuclear explosives utilizing a variant of the Teller-Ulam two-stage bomb design against a large steel pusher plate attached to the spacecraft with shock absorbers. Efficient directional explosives maximized the momentum transfer, leading to specific impulses in the range of 6,000 seconds, or about thirteen times that of the Space Shuttle main engine. With refinements a theoretical maximum of 100,000 seconds (1 MN·s/kg) might be possible. Thrusts were in the millions of tons, allowing spacecraft larger than 8×106 tons to be built with 1958 materials.

The reference design was to be constructed of steel using submarine-style construction with a crew of more than 200 and a vehicle takeoff weight of several thousand tons. This low-tech single-stage reference design would reach Mars and back in four weeks from the Earth's surface (compared to 12 months for NASA's current chemically powered reference mission). The same craft could visit Saturn's moons in a seven-month mission (compared to chemically powered missions of about nine years). 

A number of engineering problems were found and solved over the course of the project, notably related to crew shielding and pusher-plate lifetime. The system appeared to be entirely workable when the project was shut down in 1965, the main reason being given that the Partial Test Ban Treaty made it illegal (however, before the treaty, the US and Soviet Union had already detonated at least nine nuclear bombs, including thermonuclear bombs, in space, i.e., at altitudes over 100 km: see high-altitude nuclear explosions). There were also ethical issues with launching such a vehicle within the Earth's magnetosphere: calculations using the now disputed linear no-threshold model of radiation damage showed that the fallout from each takeoff would kill between 1 and 10 people. In a threshold model, such extremely low levels of thinly distributed radiation would have no associated ill-effects, while under hormesis models, such tiny doses would be negligibly beneficial. With the possible use of less efficient clean nuclear bombs for achieving orbit and then more efficient higher yield dirty bombs for travel would bring down the amount of fallout caused from an Earth-based launch by a significant factor. 

One useful mission for this near-term technology would be to deflect an asteroid that could collide with the Earth, depicted dramatically in the 1998 film Deep Impact, even though it was a comet in that particular film. The extremely high performance would permit even a late launch to succeed, and the vehicle could effectively transfer a large amount of kinetic energy to the asteroid by simple impact, and in the event of an imminent asteroid impact a few predicted deaths from fallout would probably not be considered prohibitive. Also, an automated mission would eliminate the most problematic issues of the design: the shock absorbers.

Orion is one of very few interstellar space drives that could theoretically be constructed with available technology, as discussed in a 1968 paper, Interstellar Transport by Freeman Dyson

Project Daedalus

Project Daedalus was a study conducted between 1973 and 1978 by the British Interplanetary Society (BIS) to design a plausible interstellar unmanned spacecraft that could reach a nearby star within one human scientist's working lifetime or about 50 years. A dozen scientists and engineers led by Alan Bond worked on the project. At the time fusion research appeared to be making great strides, and in particular, inertial confinement fusion (ICF) appeared to be adaptable as a rocket engine. 

ICF uses small pellets of fusion fuel, typically lithium deuteride (6Li2H) with a small deuterium/tritium trigger at the center. The pellets are thrown into a reaction chamber where they are hit on all sides by lasers or another form of beamed energy. The heat generated by the beams explosively compresses the pellet, to the point where fusion takes place. The result is a hot plasma, and a very small "explosion" compared to the minimum size bomb that would be required to instead create the necessary amount of fission. 

For Daedalus, this process was run within a large electromagnet which formed the rocket engine. After the reaction, ignited by electron beams in this case, the magnet funnelled the hot gas to the rear for thrust. Some of the energy was diverted to run the ship's systems and engine. In order to make the system safe and energy efficient, Daedalus was to be powered by a helium-3 fuel that would have had to be collected from Jupiter

Medusa

Conceptual diagram of a Medusa propulsion spacecraft, showing: (A) the payload capsule, (B) the winch mechanism, (C) the optional main tether cable, (D) riser tethers, and (E) the parachute mechanism.
 
Operating sequence of the Medusa propulsion system. This diagram shows the operating sequence of a Medusa propulsion spacecraft (1) Starting at moment of explosive-pulse unit firing, (2) As the explosive pulse reaches the parachute canopy, (3) Pushes the canopy, accelerating it away from the explosion as the spacecraft plays out the main tether with the winch, generating electricity as it extends, and accelerating the spacecraft, (4) And finally winches the spacecraft forward to the canopy and uses excess electricity for other purposes.
 
The Medusa design is a type of nuclear pulse propulsion which has more in common with solar sails than with conventional rockets. It was envisioned by Johndale Solem in the 1990s and published in the Journal of the British Interplanetary Society (JBIS).

A Medusa spacecraft would deploy a large "spinnaker" sail ahead of it, attached by separate independent cables, and then launch nuclear explosives forward to detonate between itself and its sail. The sail would be accelerated by the plasma and photonic impulse, running out the tethers as when a fish flees the fisherman, and generating electricity at the "reel". The spacecraft would then use some of the generated electricity to reel itself up towards the sail, constantly smoothly accelerating as it goes.

In the original design, multiple tethers connected to multiple motor generators. The advantage over the single tether is to increase the distance between the explosion and the tethers, thus reducing damage to the tethers.

For heavy payloads, performance could be improved by taking advantage of lunar materials, for example, wrapping the explosive with lunar rock or water, likely stored previously at a stable Earth-Moon Lagrange point to be subsequently acquired by the Medusa spacecraft.

Medusa performs better than the classical Orion design because its sail intercepts more of the explosive impulse, its shock-absorber stroke is much longer, and all its major structures are in tension and hence can be quite lightweight. Medusa-type ships would be capable of a specific impulse between 50,000 and 100,000 seconds (500 to 1000 kN·s/kg).

Medusa is widely known to the public in the BBC documentary film To Mars By A-Bomb: The Secret History of Project Orion. A short film shows an artist's conception of how the Medusa spacecraft works "by throwing bombs into a sail that's ahead of it".

Project Longshot

Project Longshot was a NASA-sponsored research project carried out in conjunction with the US Naval Academy in the late 1980s. Longshot was in some ways a development of the basic Daedalus concept, in that it used magnetically funneled ICF as a rocket. The key difference was that they felt that the reaction could not power both the rocket and the systems, and instead included a 300 kW conventional nuclear reactor for running the ship. The added weight of the reactor reduced performance somewhat, but even using LiD fuel it would be able to reach Alpha Centauri, the closest solar system to our own, in 100 years (approx. velocity of 13,411 km/s, at a distance of 4.5 light years - equivalent to 4.5% of light speed). 

Antimatter-catalyzed nuclear pulse propulsion

In the mid-1990s research at the Pennsylvania State University led to the concept of using antimatter to catalyze nuclear reactions. In short, antiprotons would react inside the nucleus of uranium, causing a release of energy that breaks the nucleus apart as in conventional nuclear reactions. Even a small number of such reactions can start the chain reaction that would otherwise require a much larger volume of fuel to sustain. Whereas the "normal" critical mass for plutonium is about 11.8 kilograms (for a sphere at standard density), with antimatter catalyzed reactions this could be well under one gram. 

Several rocket designs using this reaction were proposed, some which would use all-fission reactions for interplanetary missions, and others using fission-fusion (effectively a very small version of Orion's bombs) for interstellar missions. 

MSNW magneto-inertial fusion driven rocket

MSNW magneto-inertial fusion driven rocket
The Fusion Driven Rocket powered spacecraft.jpg
Concept graphic of a fusion-driven rocket powered spacecraft arriving at Mars
DesignerMSNW LLC
ApplicationInterplanetary
StatusTheoretical
Performance
Specific impulse1,606 s to 5,722 s (depending on fusion gain)
Burn time1 day to 90 days (10 days optimal with gain of 40)
References
References
Notes
  • Fuel: Deuterium-tritium cryogenic pellet
  • Propellent: Lithium or aluminum
  • Power requirements: 100 kW to 1,000 kW

NASA funded MSNW LLC and the University of Washington in 2011 to study and develop a fusion rocket through the NASA Innovative Advanced Concepts NIAC Program.

The rocket uses a form of magneto-inertial fusion to produce a direct thrust fusion rocket. Powerful magnetic fields cause large metal rings (likely made of lithium, where a set for one pulse has a total mass of 365 grams) to collapse around the deuterium-tritium plasma, compressing it to a fusion state. Energy from these fusion reactions heats and ionizes the shell of metal formed by the crushed rings. The hot, ionized metal is shot out of a magnetic rocket nozzle at a high speed (up to 30 km/s). Repeating this process roughly every minute would propel the spacecraft. The fusion reaction is not self-sustaining and requires electrical energy to induce fusion. With electrical requirements estimated to be between 100 kW to 1,000 kW (300 kW average), spacecraft designs incorporate solar panels to produce the electrical energy needed for the fusion engine.

This approach uses Foil Liner Compression to create a fusion reaction of the proper energy scale to be used for space propulsion. The proof of concept experiment in Redmond, Washington, will use aluminum liners for compression. However, the actual rocket design will run with lithium liners.

The performance characteristics of the engine are highly dependent on the Fusion energy gain factor achieved by the reactor. Gains are expected to be between a factor of 20 and 200, with an estimated average of 40. With higher fusions gains comes higher exhaust velocity, higher specific impulse and lower electrical power requirements. The table below summarizes different performance characteristics for a theoretical 90-day Mars transfer at gains of 20, 40 and 200.

FDR parameters for 90 Mars transfer burn
Total gain Gain 20 Gain 40 Gain 200
Liner mass (kg) 0.365 0.365 0.365
Specific impulse (s) 1,606 2,435 5,722
Mass fraction 0.33 0.47 0.68
Specific mass (kg/kW) 0.8 0.53 0.23
Mass propellant (kg) 110,000 59,000 20,000
Mass initial (kg) 184,000 130,000 90,000
Electrical power
required (kW)
1,019 546 188

By April 2013, MSNW had demonstrated subcomponents of the systems: heating deuterium plasma up to fusion temperatures and have concentrated the magnetic fields needed to create fusion. They planned to put the two technologies together for a test before the end of 2013.

They could later be scaled up in power and plan to add the necessary fusion fuel (deuterium) by the end (Sept 2014) of the NIAC Study.

Breakthrough Starshot

From Wikipedia, the free encyclopedia
https://en.wikipedia.org/wiki/Breakthrough_Starshot
 
On 24 August 2016, ESO hosted a press conference to discuss the announcement of exoplanet Proxima b at its headquarters in Germany. In this picture, Pete Worden giving a speech.
 
Breakthrough Starshot is a research and engineering project by the Breakthrough Initiatives to develop a proof-of-concept fleet of light sail spacecraft named StarChip, to be capable of making the journey to the Alpha Centauri star system 4.37 light-years away. It was founded in 2016 by Yuri Milner, Stephen Hawking, and Mark Zuckerberg.

A flyby mission has been proposed to Proxima Centauri b, an Earth-sized exoplanet in the habitable zone of its host star, Proxima Centauri, in the Alpha Centauri system. At a speed between 15% and 20% of the speed of light, it would take between twenty and thirty years to complete the journey, and approximately four years for a return message from the starship to Earth. 

The conceptual principles to enable this interstellar travel project were described in "A Roadmap to Interstellar Flight", by Philip Lubin of UC Santa Barbara. Sending the lightweight spacecraft involves a multi-kilometer phased array of beam-steerable lasers with a combined coherent power output of up to 100 GW.

General

The project was announced on 12 April 2016 in an event held in New York City by physicist and venture capitalist Yuri Milner, together with cosmologist Stephen Hawking, who was serving as board member of the initiatives. Other board members include Facebook CEO Mark Zuckerberg. The project has an initial funding of US$100 million to initialize research. Milner places the final mission cost at $5–10 billion, and estimates the first craft could launch by around 2036. Pete Worden is the project's executive director and Professor Avi Loeb (Harvard University) chairs the Advisory Board for the project.

Leaders

Management and Advisory Committee

Objectives

The Breakthrough Starshot program aims to demonstrate a proof-of-concept for ultra-fast, light-driven nano-spacecraft, and lay the foundations for a first launch to Alpha Centauri within the next generation. Secondary goals are: Solar System exploration and detection of Earth-crossing asteroids. The spacecraft would make a flyby of, and, possibly photograph any Earth-like worlds that might exist in the system. 

Target planet

In August 2016, the European Southern Observatory (ESO) announced the detection of a planet orbiting the third star in the Alpha Centauri system, Proxima Centauri. The planet, called Proxima Centauri b, is orbiting within the habitable zone of its star, and it could be a potential target for one of the projects of Breakthrough Initiatives. 

In January 2017, Breakthrough Initiatives and the European Southern Observatory entered a collaboration to search for habitable planets in the nearby star system, Alpha Centauri. The agreement involves Breakthrough Initiatives providing funding for an upgrade to the VISIR (VLT Imager and Spectrometer for mid-Infrared) instrument on ESO's Very Large Telescope (VLT) in Chile. This upgrade will greatly increase the likelihood of planet detection in the system. 

Concept

A solar sail concept
 
The Starshot concept envisions launching a "mothership" carrying about a thousand tiny spacecraft (on the scale of centimeters) to a high-altitude Earth orbit and then deploying them. A phased array of ground-based lasers would then focus a light beam on the crafts' sails to accelerate them one by one to the target speed within 10 minutes, with an average acceleration on the order of 100 km/s2 (10,000  ɡ), and an illumination energy on the order of 1 TJ delivered to each sail. A preliminary sail model is suggested to have a surface area of 4 m × 4 m. An October 2017 presentation of the Starshot system model examines circular sails and finds that the beam director capital cost is minimized by having a sail diameter of 5 meters.

Earth-size planet Proxima Centauri b was discovered in 2016 orbiting within the Alpha Centauri system habitable zones, compelling the Breakthrough Starshot to try to aim its spacecraft within 1 astronomical unit (150 million kilometers or 93 million miles) of it. From this distance, a craft's cameras could potentially capture an image of high enough quality to resolve surface features.

The fleet would have about 1000 spacecraft, and each one (dubbed a StarChip), would be a very small centimeter-sized vehicle weighing a few grams. They would be propelled by a square-kilometre array of 10 kW ground-based lasers with a combined output of up to 100 GW. A swarm of about 1000 units would compensate for the losses caused by interstellar dust collisions en route to the target. In a detailed study in 2016 Thiem Hoang and coworkers found that mitigating the collisions with dust, hydrogen and galactic cosmic rays may not be quite as severe an engineering problem as first thought.

Technical challenges

Light propulsion requires enormous power: a laser with a gigawatt of power (approximately the output of a large nuclear plant) would provide only a few newtons of thrust. The spaceship will compensate for the low thrust by having a mass of only a few grams. The camera, computer, communications laser, a plutonium power source, and the solar sail must be miniaturized to fit within a mass limit. All components must be engineered to endure extreme acceleration, cold, vacuum, and protons. The spacecraft will have to survive collisions with space dust; Starshot expects each square centimeter of frontal cross-section to collide at high speed with about a thousand particles of size at least 0.1 μm. Focusing a set of lasers totaling one hundred gigawatts onto the solar sail will be difficult due to atmospheric turbulence, so there is the suggestion to use space-based laser infrastructure. According to The Economist, at least a dozen off-the-shelf technologies will need to improve by orders of magnitude.

StarChip

StarChip is the name used by Breakthrough Initiatives for a very small, centimeter-sized, gram-scale, interstellar spacecraft envisioned for the Breakthrough Starshot program, a proposed mission to propel a fleet of a thousand StarChips on a journey to the Alpha Centauri star system, the nearest extrasolar stars, about 4.37 light-years from Earth. The journey may include a flyby of Proxima Centauri b, an Earth-sized exoplanet that is in the habitable zone of its host star. The ultra-light StarChip robotic nanocraft, fitted with lightsails, are planned to travel at speeds of 20% and 15% of the speed of light, taking between 20 and 30 years to reach the star system, respectively, and about 4 years to notify Earth of a successful arrival. The conceptual principles to enable practical interstellar travel were described in "A Roadmap to Interstellar Flight", by Philip Lubin of UC Santa Barbara, who is an advisor for the Starshot project. 

In July 2017, scientists announced that precursors to StarChip, named Sprites, were successfully launched and flown through Polar Satellite Launch Vehicle by ISRO from Satish Dhawan Space Centre. Sprites will also be flown on the KickSat-2 mission scheduled for November 2018. 

Components

Each StarChip nanocraft is expected to carry miniaturized cameras, navigation gear, communication equipment, photon thrusters and a power supply. In addition, each nanocraft would be fitted with a meter-scale lightsail, made of lightweight materials, with a gram-scale mass.

Cameras

Four sub-gram scale digital cameras, each with a minimum 2-megapixels resolution, are envisioned.

Processors

Four sub-gram scale processors are planned.

Photon thrusters

Four sub-gram scale photon thrusters, each minimally capable of performing at a 1W diode laser level, are planned.

Battery

A 150 mg atomic battery, powered by plutonium-238 or americium-241, is planned.

Protective coating

A coating, possibly made of beryllium copper, is planned to protect the nanocraft from dust collisions and atomic particle erosion.

Lightsail

The lightsail is envisioned to be no larger than 4 by 4 meters (13 by 13 feet), possibly of composite graphene-based material. The material would have to be very thin and be able to reflect the laser beam while absorbing only a small fraction of the incident energy, or it will vaporize the sail.

Other potential destinations

The table below lists possible target stars for similar photogravitational assist travel. The travel times are for the spacecraft to travel to the star and then enter orbit around the star (using photon pressure in maneuvers similar to aerobraking).

Name Travel time
(yr)
Distance
(ly)
Luminosity
(L)
Proxima Centauri 121 4.2 0.00005
α Centauri A 101.25 4.36 1.52
α Centauri B 147.58 4.36 0.50
Sirius A 68.90 8.58 24.20
Procyon A 154.06 11.44 6.94
Vega 167.39 25.02 50.05
Altair 176.67 16.69 10.70
Fomalhaut A 221.33 25.13 16.67
Denebola 325.56 35.78 14.66
Castor A 341.35 50.98 49.85
Epsilon Eridani 363.35 10.50 0.50
  • Successive assists at α Cen A and B could allow travel times to 75 yr to both stars.
  • Lightsail has a nominal mass-to-surface ratio (σnom) of 8.6×10−4 gram m−2 for a nominal graphene-class sail.
  • Area of the Lightsail, about 105 m2 = (316 m)2
  • Velocity up to 37,300 km s−1 (12.5% c)

Other applications

The German physicist Claudius Gros has proposed that the technology of the Breakthrough Starshot initiative may be utilized in a second step to establish a biosphere of unicellular microbes on otherwise only transiently habitable exoplanets. A Genesis probe would travel at lower speeds, about 0.3% of the speed of light. It could hence be decelerated using a magnetic sail.

National Space Society

From Wikipedia, the free encyclopedia
https://en.wikipedia.org/wiki/National_Space_Society
 
National Space Society
Nss-logo-whitebackground.jpg
Founded1987
TypeSpace advocacy, 501(c)3 Education
Location
Area served
Worldwide
Websitenss.org

The National Space Society (NSS) is an American international nonprofit 501(c)(3) educational and scientific organization specializing in space advocacy. It is a member of the Independent Charities of America and an annual participant in the Combined Federal Campaign. The society's vision is: "People living and working in thriving communities beyond the Earth, and the use of the vast resources of space for the dramatic betterment of humanity."

The society supports human spaceflight and robotic spaceflight, by both the public (e.g., NASA, Russian Federal Space Agency and Japan Aerospace Exploration Agency) and private sector (e.g., Ansari X Prize, Transformational Space, Scaled Composites, etc.) organizations.

History

The society was established in the United States on March 28, 1987 by the merger of the National Space Institute, founded in 1974 by Dr. Wernher von Braun, and the L5 Society, founded in 1975 based on the concepts of Dr. Gerard K. O'Neill.

The society has an elected volunteer Board of Directors and a Board of Governors. The chairman of the Board of Governors is United States Air Force Colonel Karlton Johnson (retired). The chairman of the Board of Directors is Kirby Ikin

The National Space Society was awarded the "Five-Star Best in America" award by the Independent Charities of America organization in 2005.

In 2014, the National Space Society launched the Enterprise In Space program. In order to ignite interest in space and science, technology, engineering, art and math (STEAM) education, Enterprise In Space plans to design, build, and launch a 3D-printed spacecraft into Earth orbit carrying 100+ experiments from K to postgraduate student teams. The orbiter is planned to be returned to Earth with the experiments for the student teams to analyze. 

Ad Astra

The Society publishes a magazine Ad Astra, which appears quarterly in print and electronic form. 

International Space Development Conference

The society hosts an annual International Space Development Conference (ISDC) held in major cities throughout the United States, often during or close to the Memorial Day weekend.

NSS Chapters network

Locations and "sphere of operation" of current NSS chapters in the United States (image courtesy of NSS)
 
As listed in each quarterly issue of Ad Astra, a large number of NSS chapters exist around the world. The chapters may serve a local area such as a school, city or town, or have a topical or special interest focus, such as a rocketry or astronomy club, or educational/community outreach program. Chapters are the peripheral organs of the society by organizing events, communicating with the public on the merits and benefits of space exploration, and working to educate political leaders.

Location of current NSS chapters in Australia (image courtesy of NSS)

National Space Society of Australia

A strong contingent of chapters is located in Australia. Prior to the NSI-L5 merger, the L5 Society had been developing chapters around the world, and in Australia, three chapters had been established. The 'Southern Cross L5 Society' was formed in 1979, with groups in Sydney, Adelaide (in 1984) and Brisbane (in 1986). It was decided in late 1989 to create the National Space Society of Australia (NSSA) which could act as an umbrella organization.

Similar efforts have taken hold in Brazil, Canada and Mexico, as well as European countries that have a strong aerospace presence. including France, Germany, and the Netherlands.

Awards

The society administers a number of awards. These are typically presented during the annual International Space Development Conference that NSS hosts. These awards are in recognition of individual volunteer effort, awards for NSS chapter work, the "Space Pioneer" award, and two significant awards which are presented in alternate years. 

Robert A. Heinlein Memorial Award

The Robert A. Heinlein Memorial Award, is given in even-numbered years (2004, 2006, etc.) to "honor those individuals who have made significant, lifetime contributions to the creation of a free spacefaring civilization. 

Heinlein Award Winners:

NSS Von Braun Award

The NSS Von Braun Award is given in odd-numbered years (1993, 1995, etc.) "to recognize excellence in management of and leadership for a space-related project where the project is significant and successful and the manager has the loyalty of a strong team that he or she has created." Awardees include:

Von Braun Award Winners:

Other scholarships and award activities

Other scholarships and award activities NSS provides or assists with include the following awards:
  • The Space Pioneer Awards
  • The NSS-ISU scholarship, worth $12,000, to the International Space University. Application deadline is December 31 of each year, for study during the following year. The 2005 recipient was Robert Guinness of St. Louis;
  • EURISY international youth science fiction writing competition (NSS provided US support in 2005), and;
  • Permission to Dream space adventure for students, teachers and parents from the Space Frontier Foundation which is partly sponsored by NSS.

Affiliations

The National Space Society is an alliance organization of the Meade 4M Community, the Coalition for Space Exploration, in support of the educational initiatives and outreach of NSS, and a founding executive member of the Alliance for Space Development.

The Mote in God's Eye (Niven and Pournelle)

From Wikipedia, the free encyclopedia
https://en.wikipedia.org/wiki/The_Mote_in_God's_Eye
 
The Mote in God's Eye
The Mote In God's Eye - original hardcover edition.jpg
First edition (hardcover)
AuthorLarry Niven & Jerry Pournelle
CountryUnited States
LanguageEnglish
SeriesCoDominium
GenreScience fiction
PublisherSimon & Schuster
Publication date
1974
Media typePrint (hardback & paperback)
Pages537
ISBN0-671-21833-6
OCLC934734
813/.5/4
LC ClassPZ4.N734 Mo PS3564.I9
Followed byThe Gripping Hand 

The Mote in God's Eye is a science fiction novel by American writers Larry Niven and Jerry Pournelle, first published in 1974. The story is set in the distant future of Pournelle's CoDominium universe, and charts the first contact between humanity and an alien species. The title of the novel is a wordplay on the Biblical "The Mote and the Beam" parable and is the nickname of a star. The Mote in God's Eye was nominated for the Hugo, Nebula and Locus Awards in 1975.
 

Setting

The Mote in God's Eye (originally titled Motelight) is set in Pournelle's CoDominium universe, where a union of the United States and the Soviet Union produced a world government and a number of colonies in other star systems, followed by nuclear war on Earth and the rise of the First Empire based on the planet Sparta several centuries before the events of the novel. There is a reference to these events in Pournelle's novel King David's Spaceship.

Many, but not all, humans are part of the Second Empire, held together by an interstellar navy modeled on 19th century British lines, with all-male crews, a highly competent officer corps grown from midshipmen recruited in their teens and trained on the job, and well-armed and -organized Marines to carry out ground missions. Those who prove themselves worthy can be promoted into the aristocracy. The aristocrats themselves tend more towards duty than privilege. The Empire is predominantly Christian, but other religions are more or less tolerated. The people of the planet Dayan are Jewish, while Horace Bury is a Muslim business magnate from Levant. An upstart religion, the "Church of Him", which was founded when the Mote became intensely bright and was regarded as part of the Face of God, is shown in decline, its founder having committed suicide when the light from the Mote went out.

Plot summary

In the year AD 3017, humanity is slowly recovering from an interstellar civil war that tore apart the first Empire of Man. The Second Empire is busy establishing control over the remnants of its predecessor, by force if necessary. After a rebellion on the planet New Chicago is quashed, Captain Bruno Cziller of the Imperial battlecruiser INSS MacArthur remains behind as Chief of Staff to the new governor, while Commander Roderick Blaine is given temporary command of the ship, along with secret orders to take Horace Hussein Bury, a powerful interstellar merchant suspected of instigating the revolt, to the Imperial capital, Sparta. Another passenger is Lady Sandra Bright "Sally" Fowler, the niece of an Imperial senator and a traumatized former prisoner of the rebels.

New Caledonia is the capital of the Trans-Coalsack sector, on the opposite side of the Coalsack Nebula from Earth. Also in the sector is a red supergiant star known as Murcheson's Eye. Associated with it is a yellow Sun-like star, which from New Caledonia appears in front of the Eye. Since some see the Eye and the Coalsack as the face of God, the yellow star is known as the Mote in God's Eye.

Human ships use the Alderson Drive, which allows them to travel instantaneously between "Alderson points" in specific star systems. Approaching New Caledonia, MacArthur is ordered to investigate when an alien spacecraft, propelled by a solar sail, is detected. After the spacecraft fires upon MacArthur, Blaine has its main capsule detached from the sail and taken aboard. Its sole occupant, a brown and white furred creature, is found dead.

After much debate, MacArthur and the battleship Lenin are sent to the star from which the alien ship came, the Mote. MacArthur carries civilian researchers to make first contact with the aliens, or "Moties" as they are quickly nicknamed. Admiral Kutuzov, aboard Lenin, has strict orders to avoid all contact with the aliens and ensure that human technology does not fall into their hands. The Moties seem friendly and have advanced technology that they are willing to trade, much to Bury's delight. Although they also possess the Alderson Drive, none of their ships have ever returned. This is because, unknown to the Moties, the Mote's only Alderson exit point lies within the outer layers of the star Murcheson's Eye. Human warships can survive there for a limited time because of their protective Langston Fields, which the Moties do not have.

The Moties are an old species, native to a planet that the humans label Mote Prime, that has evolved into many specialized subspecies. The first taken aboard MacArthur is an "Engineer", possessing amazing technical abilities, but limited speech and free will. It brings along a pair of tiny "Watchmakers" as helpers. Some days later, a delegation of "Mediators" (like the dead pilot of the probe ship) arrive. Their specialty is communication and negotiation. The Mediators invite the humans to send a party to Mote Prime. After some debate, the invitation is accepted. Each person in this group acquires a "Fyunch(click)", a Mediator who studies their human subject and tries to learn how to think like them.

Back on MacArthur, the Watchmakers escape, and although it is assumed they have died, they have actually been breeding furiously out of sight. Undetected by the crew, they modify parts of MacArthur to suit their needs. When they are discovered, several attempts to rid MacArthur of the infestation fail, and a battle for control of the ship erupts. The crew is eventually forced to abandon ship after suffering casualties. The party on Mote Prime is quickly recalled without explanation and told to rendezvous with Lenin. Once MacArthur is evacuated, Lenin fires on her to prevent the potential capture of human technology. This reveals that the Watchmakers have improved MacArthur's Langston Field. Nevertheless, MacArthur is destroyed.

During the evacuation, MacArthur midshipmen Staley, Whitbread and Potter are cut off and forced to escape in Watchmaker-modified lifeboats. The lifeboats automatically land in a sparsely populated area of Mote Prime. There the midshipmen find a fortified museum. It provides evidence of a very long and violent history, though the Moties had carefully portrayed themselves as completely peaceful. Following this discovery, the midshipmen are tracked down by Whitbread's Mediator Fyunch(click), who reveals that Moties (other than the short-lived, sterile Mediators) must become pregnant periodically or die. This inevitably results in overpopulation ... and civilization-ending wars. The Masters, whom the Mediators obey, have also concealed the existence of one Motie subspecies from the humans: Warriors more deadly than any human, even Sauron supersoldiers.

The museums exist to help restore civilization after a collapse. The "Cycles" of civilization, war, and collapse have gone on for hundreds of thousands of years, leaving the Moties fatalistically resigned to their destiny. Only a mythical character called "Crazy Eddie" believes there is a way to change this, and any Motie who comes to believe a solution is possible is labeled a "Crazy Eddie" and deemed insane.

The current civilization utilizes a type of industrial feudalism, with coalitions of Masters governing the planet. One faction, led by "King Peter", wanted to reveal the truth to the humans, but was overruled. Colonization of other planets would inexorably bring about conflict with humans, as the inevitable Motie population explosion would force them to seek to take over human worlds. Nonetheless, the more powerful coalition sees this temporary solution as preferable to the impending collapse. Both factions send Warriors after the midshipmen, one to capture them, the other to rescue them. The stronger group's Warriors trap the midshipmen, but the trio refuse to surrender and die as a result.

Unaware of the midshipmen's fate, Lenin leaves the Mote system, taking with it three ambassadors, a sterile Master and two Mediators, whose mission is to open the galaxy to their species while concealing their terrible secrets.

An Imperial Commission is on the verge of granting colonies to the Moties, but MacArthur Sailing Master/Lieutenant Kevin Renner figures out the truth just in time. It is the passengers on the original probe, ejected into space and burned up by solar radiation, that give the game away. Not only is there a Warrior among the group, but several are visibly pregnant, demolishing any argument about them being statues or religious icons.

The decision is made to gather a battle fleet to either disarm or try to annihilate the Moties. The ambassadors are faced with the extinction of their species, knowing that the Masters would never submit. However, a Mediator comes up with a third option: a blockade of the system's only Alderson exit point. This plan is adopted, over the strenuous opposition of Bury, who views the Moties as the greatest threat humanity has ever faced. 

Characters

Commander Roderick "Rod" Blaine 
A navy officer and member of an influential aristocratic family, Blaine is promoted to captain of the Imperial battlecruiser INSS MacArthur. On return to New Scotland from the Mote, he is retired from active service and appointed to the Commission charged with negotiating with the Moties.
Lady Sandra "Sally" Bright Fowler 
After leaving the Imperial University at Sparta with a master's degree in anthropology, she and a classmate named Dorothy embarked on a trip to study primitive cultures (such as human colonies isolated by the civil war) first hand. They became caught up in the revolution on New Chicago. Dorothy disappeared and Sally was imprisoned in a concentration camp, where she took on a leadership role. Months later, she and her servants were rescued by Imperial forces. The niece of an Imperial senator, she is sent home aboard MacArthur, then recruited for the expedition to the Mote based on her skills.
His Excellency Horace Hussein Chamoun al Shamlan Bury 
An Imperial magnate, Chairman of the Board of Imperial Autonetics, and a leading member of the Imperial Traders Association, Bury instigates the rebellion on New Chicago. The Navy suspects his involvement, so he is made a virtual, though unofficial, prisoner aboard MacArthur, with the intent of sending him to New Sparta to face the judgement of the Imperial Court. Although rich, he is not in a position to bribe Blaine, whose family is even richer. His experiences during the evacuation of MacArthur turn him into an advocate for isolating or even destroying the Moties.
Nabil 
Bury's servant, skilled with dagger and poison. Travels with Bury to New Scotland, the Mote, and eventually to Sparta. At Bury's command, he captures two "Watchmaker" Moties and places them in a spacesuit's air tank in suspended animation. Later Bury throws the tank away, having become intensely fearful of Moties.
Commander Jack Cargill
First lieutenant of MacArthur, promoted to executive officer after the battle of New Chicago.
Commander Jock (Sandy) Sinclair
MacArthur's chief engineer. Born in New Scotland.
Jonathon Whitbread 
A MacArthur midshipman, he becomes the first man to make contact with a living Motie. He has an easygoing personality in contrast to his shipmate Horst Staley. Whitbread is described as being "17 standard years old", slightly younger than the more senior Staley.
Horst Staley 
A MacArthur midshipman. Born on the former rebel planet Sauron, he adheres rigidly to naval regulations and the chain of command, and displays no sense of humor. Like the other midshipman, Staley is still in his teens. Despite this, he is put in command of a boarding party of marines ordered to rescue trapped passengers and retrieve Motie technology during the evacuation of MacArthur.
Gavin Potter 
A MacArthur midshipman. Born on New Scotland, he joins the crew when MacArthur refuels at a moon of one of the outer planets in the New Caledonia system. Potter serves as the guide to New Scot culture for other characters, particularly the cult known as the Church of Him. He describes the intense light seen coming from the Mote a century earlier, convincing the crew that the incoming probe from there was launched using lasers.
Kevin Renner 
The sailing master of MacArthur and former merchant navy officer does not regard himself as a permanent Navy officer. He displays a somewhat irreverent attitude towards the Navy and its traditions while supporting the Imperial Aristocracy style of government.
Admiral Lavrenti Kutuzov 
Kutuzov is chosen to command the mission to the Mote because of his ruthless devotion to duty by whatever means are necessary: He once reduced a populated planet to ashes in order to stop a dangerous rebellion against the Empire of Man.
Senator Benjamin Bright Fowler 
Sally's uncle, dispatched to New Scotland to meet Lenin on return from the Mote, and head of the Commission to negotiate with Moties.
Father David Hardy 
The ship's chaplain aboard MacArthur and an expert linguist, he becomes part of the team that meets the first Motie delegation. Incorrectly regarded as "unworldly", he does not believe everything the Moties say, observing that "priests hear a lot of lies". He is also the first to interpret some Motie communication.
Dr. Anthony Horvath 
Minister of Science for Trans-Coalsack sector. Leader of the New Scotland science delegation to the Mote. He advocates for open contact with the Moties, ignorant of any threat they represent.
Dr. Jacob Buckman 
An astrophysicist whom Bury cultivates as a source of information about the activities of the rest of MacArthur's crew.
Admiral Plekhanov 
Fleet Commander in the Battle of New Chicago, then Acting Governor-General of the recaptured colony.
Bruno Cziller 
Captain commanding MacArthur, then Rear-Admiral on Plekhanov's staff on New Chicago, ceding command of his ship to Blaine.

Moties

Moties are described as bipeds, about 1.3 meters tall, covered with fur whose color depends on the subspecies. Their most obvious feature is the asymmetric arrangement of arms, with two dexterous right arms and one heavily muscled left arm whose musculature attaches to the head, so that Moties have no left ear to match the large, membrane-like right ear. The backbone is jointed rather than flexible and the entire upper body swivels to turn the head. The face is simple and incapable of expression. Gestures replace facial expression. 

Master Moties have all white fur, described as silky. Engineers have brown fur, while Mediators have patchy fur in brown and white. They are sterile hybrids of Masters and Engineers. Siblings tend to have identical patterns of patches. Masters are obeyed by all other Moties, though Mediators have some independence to negotiate between Masters. Other Motie subspecies include Warriors, optimized for hand-to-hand combat and weapon usage, Doctors with extra dexterity, and semi-sentient Farmers who raise crops. The Watchmaker species is related to Moties but is about one-third the size and has four arms in a symmetrical arrangement.

Moties alternate between sexes as part of their reproductive cycle, except for Mediators who cannot reproduce and have shorter lives. Mediators are referred to as females throughout the novel. Master Moties may become sterile males with hormone treatment, at which point they can become "Keepers", preserving common resources that should not be fought over.
The Asteroid Miner 
After MacArthur appears in the system, the first ship to rendezvous comes from a group of Trojan asteroids related to the only gas giant planet. The pilot is a Brown Motie, an "idiot savant engineer" with instinctive understanding of science and technology, amazing dexterity, and poor communication skills. Whitbread boards the Miner's ship and finds it occupied by the Miner and dozens of Watchmakers, smaller Moties with similar abilities but lower intelligence. The Miner accompanies Whitbread back to MacArthur, bringing two Watchmakers and killing the rest by evacuating her ship's air. The humans are unable to communicate with the Miner, not realizing her status, but discover her ability to improve gadgets. Before the next delegation of Moties arrives, the Miner dies from failing to become pregnant in time. The Watchmakers reproduce in vast numbers and re-make MacArthur under the humans' noses, eventually leading to the ship's evacuation and destruction.
Whitbread's Motie 
When the midshipmen land on Mote Prime, Whitbread's Fyunch(click) arrives in an aircraft with "Charlie", another Mediator, and a Brown Motie technician. Whitbread's Motie serves a Master Motie who was given jurisdiction over interaction with humans, but will kill the midshipmen rather than expose the truth about Moties. At this point all the other Fyunch(click) Mediators are either "Crazy Eddie" or helping their Master. She is instrumental in helping the midshipmen get away from the Museum, explaining their peril to them, and instructing the Brown to work on weapons and transport for them. She apparently kills Whitbread to prevent his capture, Whitbread having done the same for Potter while Staley died fighting, and is later executed in shame for having killed her Fyunch(click).
"Charlie" 
Charlie is a Mediator whose Master, called "King Peter", is willing to protect the midshipmen and send them home. Charlie regards Whitbread's Motie as Crazy Eddie but is willing to work with her to prevent a war. Later Charlie is one of the Motie ambassadors to the human Empire. It is Charlie who suggested the blockade of the Motie system, to prevent the annihilation of her species.
"Ivan" 
Ivan is a "Keeper", a sterile Master Motie in the male phase who cannot have children and theoretically has no interest in dynastic conflict. Keepers have jurisdiction over vital common resources, such as the Museums. Ivan is the official Ambassador from the Moties to humans.
"Jock" 
Jock is a Mediator, and is the third ambassador to the humans. She was in the first delegation of Moties that met MacArthur but did not become a Fyunch(click). She serves the same Master as Whitbread's Motie. Her job was to study Kutuzov, the one human who commanded all the others but never communicated with Moties.

Crazy Eddie

The Moties frequently refer to the mythical character they call "Crazy Eddie" when talking to humans. There are many Crazy Eddie stories, but all revolve around the inevitability of repeated cycles of collapse of Motie civilization and the pointlessness of trying to prevent them. The drive that humans call the Alderson Drive, which allows human ships to travel between star systems, is called by Moties the Crazy Eddie Drive, because although it is founded in sound science and has been reinvented many times by Motie civilizations, ships that attempt to use it disappear and are never seen again. The Moties do not know that the ships they send appear inside the hot photosphere of Murcheson's Eye. Human ships are protected by the energy-absorbing Langston Field. The point in space where the Alderson Drive operates is known to the Moties as the Crazy Eddie Point. This is the title of the second part of the novel. The other parts are titled "The Crazy Eddie Probe", "Meet Crazy Eddie", and "Crazy Eddie's Answer". From the Moties point of view, humans are Crazy Eddie. Several Moties, including Rod Blaine's Fyunch(click), become Crazy Eddie after exposure to human attitudes. 

Reception

Robert A. Heinlein, while giving the authors extensive advice on a draft manuscript, described it as "a very important novel, possibly the best contact-with-aliens story ever written". Theodore Sturgeon, writing in Galaxy, described The Mote in God's Eye as "one of the most engrossing tales I have encountered in years", stating that "the overall pace of the book [and] the sheer solid story of it" excuse whatever flaws might remain, with the one complaint being that he found it unlikely the Moties would not have used genetic engineering at some point to curb their population growth. Portsmouth Times reviewer Terry McLaughlin found the novel "a superior tale, told without the pseudo-psychology background that seems to mar many a new science fiction novel."

Brian W. Aldiss and David Wingrove reported that while the imagined aliens were "fascinating creations", the "style and characterization [emphasize] the weaknesses of both Niven and Pournelle."

Awards and nominations

Sequels

Pournelle and Niven followed up with the sequel The Gripping Hand and in 2010 Pournelle's daughter, Jennifer, published an authorized sequel entitled Outies

Other related works

60,000 words were cut from the novel before publication. The short story "Reflex" was instead published in 1983 in the first There Will Be War collection, edited by Pournelle and John F. Carr. It details an early phase of the battle for New Chicago, told from the rebels' point of view. MacArthur, with Captain Cziller in command and Blaine as Exec, engages and defeats a rebel ship, but because of the technology, particularly the Langston Field, the ship is still deadly and surrender is a complex matter. Midshipman Horst Staley is sent to board and disable the ship while carrying a suicide bomb to prevent interference. He makes a mistake, allowing the "political officer" aboard the ship to snatch away the bomb, but the crew who are sick of the revolt overpower the officer. This preys on his mind during the events of the main novel. The rebel ship was taken over as the prize ship Defiant, commanded by Blaine during the final battle.

"Motelight" was also originally written as part of the novel, but was never published except as part of the non-fiction piece "Building 'The Mote in God's Eye'" that appeared in Pournelle's collection "A Step Farther Out". It describes how two astronomers on New Scotland try to continue their work during the war with New Ireland, and are thus the first to see the sudden brightening of the Mote due to the laser launch system being activated. The rest of the population are hiding under the Langston Fields protecting their cities from bombardment, until one day the field fails and they see the Coal Sack with a glowing green Eye. The story also mentions "Howard Grote Littlemead", who believes that the bright Mote really is the Eye of God, and founds the Church of Him. It is in one of the churches that Potter shows Renner and Staley a holographic picture of the Coal Sack showing the intense green glow of the Mote. 

Larry Niven also wrote a poem "In Memoriam : Howard Grote Littlemead" that was published much later.

Lie point symmetry

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