DIA, 2010: estudos do AAWSAP propõem aviões movidos a pósitrons e naves impulsionadas por microexplosões de fusão

UNCLASSIFIED//[FOR OFFICIAL USE ONLY, struck through] Defense Intelligence Reference Document Acquisition Threat Support 2 March 2010 ICOD: 1 December 2009 DIA-08-1003-002 Positron Aerospace Propulsion

Positron Aerospace Propulsion Prepared by: Acquisition Support Division (DWO-3) Defense Warning Office Directorate for Analysis Defense Intelligence Agency Author: AAP Person 69 Administrative Note COPYRIGHT WARNING: Further dissemination of the photographs in this publication is not authorized. This product is one in a series of advanced technology reports produced in FY 2009 under the Defense Intelligence Agency, Defense Warning Office's Advanced Aerospace Weapon System Applications (AAWSA) Program. Comments or questions pertaining to this document should be addressed to [AAP Person 1], AAWSA Program Manager, Defense Intelligence Agency, ATTN: CLAR/DWO-3, Bldg 6000, Washington, DC 20340-5100.

Positron Aerospace Propulsion Introduction Antimatter is considered an extremely attractive fuel for aerospace propulsion because of its enormous advantage in energy density over all other known sources of energy. However, because antimatter does not occur naturally and is unstable in the presence of matter, no vehicles have ever flown using it. After a short overview of the various aerospace applications of antimatter, this paper provides a detailed analysis of air-breathing turbojets and turbo-ramjet missiles, as well as rockets for manned interplanetary missions. It discusses new methods of producing and storing large numbers of antielectrons, or positrons, and compares their costs with those of antiprotons. Finally, the paper considers the prospects for the first, modest demonstration of positron propulsive flight within the next 10 years. Interplanetary missions on positron-propelled spaceships are described in detail, with estimates of positron requirements for each mission. Standalone positron power systems are described briefly. Studies of positrons as a fuel for aerospace propulsion applications have been sponsored by the Air Force Research Laboratory, Eglin Air Force Base, Florida, and the NASA Institute for Advanced Concepts, Atlanta, Georgia. This paper is an anthology of that work and not a general review of antimatter propulsion. The positron was predicted by Dirac in 1929[1] and discovered by Anderson in 1932.[2] Along with the antiproton, which was discovered in 1954,[3] the positron has the largest specific energy of any known material. Because aerospace propulsion performance is ultimately limited by specific power, this advantage was immediately appreciated. However, compared with chemical sources of energy, positrons presented new and serious production and storage challenges. Antimatter has a long history of appearing in science fiction literature, dating to a 1942 short story in Astounding Science Fiction and the 1949 book Seetee. It later appeared in the Star Trek television and film series and continues to be an appealing subject for contemporary books and films, such as Angels and Demons. Positron aerospace propulsion is now entering a critical period owing to new technologies that bear on production and storage issues. To their advantage, positrons, unlike nuclear fission and antiprotons, present no radiation or environmental safety problems.

Conclusions Conceptual designs and missions for turbojets, turbo-ramjet missiles, and interplanetary rockets powered by positron annihilation have been presented. Positron requirements range from 150 micrograms for a globe-encircling UAV turbojet flight to 100 milligrams for a mission to Mars. A positron-powered SSRV could take off from Earth horizontally, go to LEO, launch to Mars for a 1-year exploration of the Red Planet, and return to LEO and then Earth with a horizontal landing without refueling. Within 10 years, the 150 µg of positrons required for a globe-encircling, nonstop turbojet flight could be made in 6 months at a cost of $69 million. This first-ever antimatter voyage, approximately 90 years after Lindbergh's 1927 Spirit of St. Louis transatlantic flight, would stir the public's imagination and eventually lead to positron-powered exploration of the solar system in the 21st century. New developments in stabilizing and storing positronium atoms in a matrix of dilute materials are encouraging. Lifetimes of 10 µs have been achieved, and tens-of-millisecond lifetimes are expected in the next round of experiments. Present limits are due to interactions on the walls of the trap container. Application of oscillating gradient electric fields to the huge electric dipole moment of the stable Ps atom should mitigate this problem. With the issue of stabilization in crossed fields now settled, very long lifetimes are but a matter of engineering!

UNCLASSIFIED//[FOR OFFICIAL USE ONLY, struck through] Defense Intelligence Reference Document Acquisition Threat Support 11 March 2010 ICOD: 1 December 2009 DIA-08-1003-007 Advanced Nuclear Propulsion for Manned Deep Space Missions

Advanced Nuclear Propulsion for Manned Deep Space Missions Prepared by: Acquisition Support Division (DWO-3) Defense Warning Office Directorate for Analysis Defense Intelligence Agency Author: AAP Person 72 Administrative Note COPYRIGHT WARNING: Further dissemination of the photographs in this publication is not authorized. This product is one in a series of advanced technology reports produced in FY 2009 under the Defense Intelligence Agency, Defense Warning Office's Advanced Aerospace Weapon System Applications (AAWSA) Program. Comments or questions pertaining to this document should be addressed to [AAP Person 1], AAWSA Program Manager, Defense Intelligence Agency, ATTN: CLAR/DWO-3, Bldg 6000, Washington, DC 20340-5100.

Advanced Nuclear Propulsion for Manned Deep Space Missions Preface My interest in space flight dates to when I was about 10 years old and received as a birthday gift a popular book about the feasibility of space flight. From it I learned for the first time about Oberth and Goddard and of the possibility of reaching the Moon with a multistage rocket. This occurred at the same time that Hahn and Strassmann announced the discovery of nuclear fission, with the possibility of an atomic bomb by a fission chain reaction. Having been born in Germany in 1929, I received my Ph.D. in physics under Heisenberg in 1955. Inspired by the 15-megaton hydrogen bomb test conducted by the United States in 1952, I have been deeply interested in the nonfission ignition of thermonuclear reactions by inertial confinement since 1954. At the time all fusion research in the United States was still classified, but I had quite independently discovered the basic principles of inertial confinement, the Guderley convergent shock wave, and the Rayleigh imploding shell solutions. In 1956 I presented my findings at a meeting organized by von Weizsäcker at the Max Planck Institute in Goettingen. The abstracts of this meeting reside today in the University of Stuttgart library. In 1958 I had delivered a paper at the 2nd United Nations Conference on the Peaceful Use of Atomic Energy on Nerva-type nuclear rocket reactors. The paper turned out to be of some importance as I was invited by the U.S. government to come to the United States under "Operation Paperclip." In San Diego I met Ted Taylor and Freeman Dyson, who were working on the famous "Orion" nuclear bomb propulsion concept. This concept is generally credited to Stanislaw Ulam, but I know from conversations I had with Heisenberg that a similar idea had been presented to Heisenberg by Wernher von Braun in Berlin in or around 1942. Because of my idea to use the Guderley convergent shock wave solution for thermonuclear ignition, Ted Taylor and Freeman Dyson were interested in my joining their group. But because at that time this work was classified and I was not yet a U.S. citizen, this was not possible. In 1967 I saw a new possibility for the nonfission ignition of thermonuclear microexplosions by intense relativistic electron and ion beams, driven by a high-voltage Marx generator. This ignition concept could be used not only to control the release of energy by nuclear fusion, but also to propel a spacecraft, replacing the pusher plate of the Orion concept with a magnetic mirror, reflecting the plasma-fireball of the thermonuclear microexplosion (Reference 1, 2). This idea was adopted by the British Interplanetary Society in its 1978 Project Daedalus starship study, replacing a neutron-rich deuterium-tritium (DT) thermonuclear explosive with a neutron-poor deuterium-helium3 (DHe3) explosive (Reference 3). Unlike the DT reaction, in which 80 percent of the released energy goes into neutrons, most of the energy in the D-He3 reaction goes into alpha particles, which can be deflected by a magnetic mirror. But because He3 is not abundantly available everywhere, it was proposed to "mine" it from Jupiter's atmosphere. Studies have been conducted on spacecraft propulsion with the matter-antimatter annihilation reaction, however, it is an enormous technical challenge to produce antimatter in appreciable quantities. The idea of using nano-gram amounts of antimatter for the ignition of fission-fusion microexplosions appears to have credible potential, but even there the production and storage of nano-gram quantities of antimatter pose serious technical problems (Reference 4). We have little reason to expect that new fundamental laws of physics that could lead to a breakthrough in propulsion still await discovery. Very much as America was discovered only once, it is quite possible that all the fundamental laws of physics relevant to propulsion have been discovered, challenging our imagination to find out if they are sufficient to invent propulsion systems that ultimately might bring us to Earthlike planets of nearby solar systems. I conclude this preface with an imaginary talk by Ted Taylor to Freeman Dyson as recorded by the latter's son, George Dyson, in his book Project Orion - The True Story of the Atomic Spaceship (Reference 5), followed by a dream of Ted Taylor's. "Freeman's hope for the Orion had rested on the fact that there seems to be no law of nature forbidding the construction of fission-free bombs," and on the belief that "improvements in the design of the nuclear devices (by reducing the fraction of total yield due to fission) might achieve reduction factors of 10^2 to 10^3 • This belief in small, fission-free bombs has largely evaporated." "One exception is Ted (Taylor). He remains convinced that small, clean bombs could propel Orion - but he still fears more than ever that such devices would be irresistible as weapons, until we outgrow the habit of war. There are lots of different routes to that final result of a very clean bomb." "Could you make a one-kiloton explosion in which the fission yield was zero, which is bad news on the proliferation front, but could turn Orion into something quite clean?" "Freeman thinks Ted is wrong - and Ted hopes Freeman is right." I for my part think Freeman is wrong. Many years later, shortly before his death, Ted Taylor reported: "I had a dream last night, about a new form of nuclear weapon, and I am really scared of it." He reported that when he woke up, he wrote down his dream, and it appeared scientifically sound and feasible. What was it? We never will know with certainty, but I have a guess: it is the possibility of chemical superexplosives (explained in the appendix) powerful enough to ignite a thermonuclear bomb.

Introduction As Hermann Oberth proved for chemical rockets in his 1923 book The Rocket into Planetary Space (Reference 6), this paper will try to prove for thermonuclear rockets the following: • At the present state of science and technology one can build spaceships driven by deuterium thermonuclear reactions, able to reach the outer limits of the solar system. • Such spaceships permit the manned exploration of the entire solar system and beyond, with the ultimate potential to reach nearby solar systems. • The cost in research and development to build such spaceships will be high but still well within what is economically feasible. • Using the same physical principles as for deuterium fusion rockets will also lead to the realization of clean nuclear energy, justifying the expenditures for these large projects. Deuterium can be used as the rocket fuel of choice in addition to any inert material that is suitable as a propellant. This propellant material is available on most planetary bodies and particularly on the comets of the Oort cloud. The main idea is that by gradual radial expansion from the Sun by building bridges over the Oort clouds, which presumably surround all suns, Earthlike planets in neighboring solar systems can eventually be reached. The first and most important step toward this goal is to reach the focus of the Einstein gravitational lens at 550 AU (astronomical units). At this location, one can use the Sun as the lens of a super telescope, an idea first proposed by Claudio Maccone in 1993. Present knowledge is that there are planets in nearby solar systems that are likely Earthlike planets. It is only with this gigantic telescope that one can determine if life on these planets is possible. But because of the complexity of this task, a manned mission to the Einstein gravitational lens focus is likely to be needed, possible only with advanced nuclear rocket propulsion.

Conclusion If large-scale manned spaceflight has any future, a high-specific-impulse, high-thrust propulsion system is needed. The only known propulsion concept with this property is nuclear bomb propulsion. However, since large-yield nuclear explosions are for obvious reasons undesirable, the nuclear explosions should be comparatively small. But because of what Freeman Dyson described as the "tyranny of the critical mass," small fission bombs or fission-triggered fusion bombs become extravagant, with only a fraction of the nuclear material consumed.[1] In the original Orion bomb propulsion concept, the propulsive power was through the ablation of a pusher plate. There the energy is delivered to the pusher plate by the black-body radiation of the exploding bomb. The propulsion by non-fission-triggered fusion bombs not only has the advantage that it is not subject to the "tyranny of the critical mass," but the propulsive power is there delivered by the kinetic energy of the expanding hot plasma fireball repelled from the spacecraft by a magnetic mirror. This is particularly true for a pure deuterium bomb, where, compared with DT, more energy is released into charged fusion products (in a DT bomb, 80 percent of the energy goes into neutrons). Whereas in a fission explosion most of the energy is lost into space by the undirected black-body radiation, much more propulsive energy can be drawn from the plasma of a pure deuterium fusion bomb explosion, in conjunction with a magnetic mirror. Manned space flight requires lifting large masses into Earth orbit, where they are assembled into a large spacecraft. While this can be done with chemical rockets, it would be much more economical if it could be done with a chain of small nuclear explosions. Without radioactive fallout, this can be done with a chain of laser-ignited fusion bombs, with one laser for each bomb, where the lasers become part of the exhaust. Ignition can be done not by infrared chemical or CO2 lasers, as was suggested by the Los Alamos team (Reference 18), but rather by an ultraviolet laser driven by high explosives, as suggested by the author (Reference 9). Looking to the future, using deuterium-widely available on most planets of the solar system and in the Oort cloud outside the solar system-as the nuclear rocket fuel would make manned space flight to the Oort cloud possible, at a distance at about one-tenth of one light year. [1] The same is true for nuclear fission gas core rocket reactors, where much of the unburned fission fuel is lost in the exhaust.