Skip to main content

Radiance directory

See Also


“Late-time Small Body Disruptions for Planetary Defense”, King et al 2021

2021-king.pdf: “Late-time small body disruptions for planetary defense”⁠, Patrick K. King, Megan Bruck Syal, David S. P. Dearborn, Robert Managan, J. Michael Owen, Cody Raskin et al (2021-11-01; ; similar):

  • We present a fiducial simulation of the nuclear disruption of a small body.
  • We simulate the orbits of the fragments for several plausible impact scenarios.
  • We find that nuclear disruption is an effective strategy for late-time scenarios.
  • Disruption can reduce the impacting mass to ~1% by one month before impact.

Diverting hazardous small bodies on impact trajectories with the Earth can in some circumstances be impossible without risking disrupting them. Disruption is a much more difficult planetary defense scenario to assess, being linked both to the response of the body to shock loading and the much more complicated gravitational dynamics of the fragments in the solar system relative to pure deflection scenarios.

In this work we present a new simulation suite built on n-body gravitational methods that solves fragment orbits in the full gravitational system without recourse to more approximate methods.

We assess the accuracy of our simulations and the simplifying assumptions we adopt to make the system tractable, and then discuss in more detail several specific, plausible planetary defense scenarios based on real close encounters. We find that disruption can be a very effective planetary defense strategy even for very late (sub-year) interventions, and should be considered an effective backup strategy should preferred methods, which require long warning times, fail.

[Keywords: planetary defense, catastrophic disruption, potentially hazardous asteroids (PHAs), celestial mechanics, n-body simulations]

“The Physics of Space War: How Orbital Dynamics Constrain Space-to-Space Engagements”, Reesman & Wilson 2020

2020-reesman.pdf: “The Physics of Space War: How Orbital Dynamics Constrain Space-to-Space Engagements”⁠, Rebecca Reesman, James R. Wilson (2020-10-01; backlinks; similar):

As the United States and the world discuss the possibility of conflict extending into space, it is important to have a general understanding of what is physically possible and practical. Scenes from Star Wars, books, and TV shows portray a world very different from what we are likely to see in the next 50 years, if ever, given the laws of physics. To describe how physics constrains the space-to-space engagements of a conflict that extends into space, this paper lays out five key concepts:

  1. satellites move quickly,
  2. satellites move predictably,
  3. space is big,
  4. timing is everything, and
  5. satellites maneuver slowly.

It is meant to be accessible to policymakers and decision-makers, helping to frame discussions of space conflict. It does not explore geopolitical considerations.

[Review of orbital dynamics: satellites are difficult to hit with any ordinary weapon because of their speed and distance, and are most easily attacked by getting into the same orbit. However, satellites are heavily constrained by their initial fuel reserve and reliant on subtle maneuvers unfolding over many orbits to gradually approach a desired point and time; a bad position or one maneuver could easily cost the entire fuel budget. In lieu of long-distance attack capabilities like powerful lasers, attacks must be planned long in advance, and, like cyberwarfare, are more likely to resemble ambushes than conventional battle.]

“Radiance: A Novel”, Scholz et al 2013

2002-scholz-radiance: “Radiance: A Novel”⁠, Carter Scholz, Gregory Benford, Hugh Gusterson, Sam Cohen, Curtis LeMay (2013-07-06; ⁠, ; backlinks; similar):

E-book edition of the 2002 Carter Scholz novel of post-Cold War science/​technology, extensively annotated with references and related texts.

Radiance: A Novel is SF author Carter Scholz’s second literary novel. It is a roman à clef of the 1990s set at the Lawrence Livermore National Laboratory⁠, centering on two nuclear physicists entangled in corruption, mid-life crises, institutional incentives, technological inevitability, the end of the Cold War & start of the Dotcom Bubble, nuclear bombs & Star Wars missile defense program, existential risks⁠, accelerationism, and the great scientific project of mankind. (For relevant historical background, see the excerpts in the appendices⁠.)

I provide a HTML transcript prepared from the novel, with extensive annotations of all references and allusions, along with extracts from related works, and a comparison with the novella version.

Note: to hide apparatus like the links, you can use reader-mode ().

“The Physical Principles of Thermonuclear Explosives, Inertial Confinement Fusion, and the Quest for Fourth Generation Nuclear Weapons”, Gsponer & Hurni 2009

“The physical principles of thermonuclear explosives, inertial confinement fusion, and the quest for fourth generation nuclear weapons”⁠, Andre Gsponer, Jean-Pierre Hurni (2009-01-20; ⁠, ; backlinks; similar):

This report is an assessment of the prospect of developing new (ie. fourth generation) nuclear weapons in the context of the Comprehensive Nuclear Test-Ban Treaty (CTBT) that was adopted by the UN General Assembly in 1996 and of the current moratorium on nuclear testing in effect in all nuclear-weapon States.

The conclusion stresses that considerable research is underway in all five nuclear-weapon States (as well as in several other major industrialized States such as Germany and Japan) on ICF and on many physical processes that provide the scientific basis necessary to develop fourth generation nuclear weapons. Substantial progress has been made in the past few years on all these processes, and the construction of large ICF microexplosion facilities in both nuclear-weapon and non-nuclear-weapon States is giving the arms race a fresh boost. The world runs the risk that certain countries will equip themselves directly with fourth generation nuclear weapons, bypassing the acquisition of previous generations of nuclear weapons.

“F✱✱✱ You! Mr. President: Confessions of the Father of the Neutron Bomb”, Cohen & Platt 2006

2006-cohen-fuckyoumrpresidentconfessionsofthefatheroftheneutronbomb3rdedition.pdf: “F✱✱✱ You! Mr. President: Confessions of the Father of the Neutron Bomb”⁠, Samuel T. Cohen, Charles Platt (2006-01-01; ; backlinks)

“A Pedagogy of Diminishing Returns: Scientific Involution across Three Generations of Nuclear Weapons Science”, Gusterson 2005

2005-gusterson.pdf: “A Pedagogy of Diminishing Returns: Scientific Involution across Three Generations of Nuclear Weapons Science”⁠, Hugh Gusterson (2005; backlinks; similar):

A generation of historians, sociologists, and anthropologists of science has learned from actor-network theory and the sociology of scientific knowledge (SSK) to focus on the building of scientific institutions and facts, and from Thomas Kuhn to expect a certain historical rhythm in the evolution of scientific fields of knowledge: first, a dynamic burst of creativity (the “revolution”) as the foundational ideas of the new field are laid down; second, a period of “normal science” in which gaps are filled in as the new knowledge is institutionalized; and, finally, as puzzles emerge that cannot be fully explained by the established paradigm, a new burst of creativity as another generation redefines the fundamental precepts of the field.

In this essay, looking at three generations of nuclear weapons designers, I follow and then depart from the Kuhnian script. Although the first two generations of nuclear weapons scientists conformed perfectly to the Kuhnian storyline, the final story is not about the punctuated equilibrium of scientific revolution, but about a process of scientific involution as nuclear weapons science has simultaneously matured and withered in a way that is beautifully evoked in a blues ballad once sung for me by a group of weapons designers from the Lawrence Livermore National Laboratory:

Went down to Amarillo
Lookin’ for my sweet ’533
It was laying on a long white table
Looked cold and hard to me
Let it go, let it go, retire it
No city scrapers do we need
Take a 614 and modify it.
Call it the mod 11-E
Now you can search this whole world over
From Frisco to Albuquerque
You can mentor anyone that you want to
But you’ll never find designers like me
Now when I’m gone, just put me way down
In a hole off the old Orange Road.
’ttach a cable to my device can
So I can run those legacy codes (fading)
So I can run those legacy codes
So I can run those legacy codes.5

…The 1970s and the 1980s, when nuclear testing moved underground, were a period of routinization: the institutional apparatus for nuclear weapons design and testing grew, its scientific achievements shrank, and the arteries of the weapons design bureaucracy hardened. Attempts to perfect a third-generation nuclear weapon—the x-ray laser—failed and were abandoned in an atmosphere of scandal and disgrace.11 The art of weapons design progressed, but by increments rather than great leaps: weapons designers learned to squeeze greater yields out of smaller quantities of plutonium so that nuclear weapons could be made lighter and smaller, weapons were made safer through the addition of Permissive Action Links (PALS) and the substitution of Insensitive High Explosive (IHE) for conventional explosives,12 and the supercomputer codes used to model the behavior of nuclear weapons were gradually refined. The names of the men (and now women) behind these achievements are largely unknown outside the nuclear weapons bureaucracy, and in some cases their achievements are only partially known within the weapons laboratories, thanks to the compartmentalizing effects of official secrecy in the weapons complex.13

Nuclear tests were forbidden after the end of the Cold War, and the practice and pedagogy of nuclear weapons science shifted again. Forced to largely abandon their nuclear test site in Nevada—a place where the desert sands encroach on the old bowling alley and cinema, now disused, as tourist buses disgorge camera-laden voyeurs to gawk at the nuclear craters—many of the old-timers elected to retire. Those that stayed have regrouped their forces in the virtual world of simulated testing, where they are attempting to train a new generation of scientists to maintain devices they cannot test. In some ways the scientific challenges of nuclear weapons design have shrunk to microscopic proportions: new designs are not built or deployed, and even the decision to substitute a new epoxy in an aging weapon can send a tremor of fear through design teams unsure if their weapons will still work. In other ways, the scientific challenges are suddenly magnified: how to design implosion, shock wave, and laser fusion experiments that will shed light on the performance of aging nuclear weapons in the absence of nuclear testing? How to use the physics knowledge of today to understand test data, long buried in dusty filing cabinets, from the 1950s and the 1960s? And how to convert old two-dimensional codes designed for Cray supercomputers into three-dimensional codes that can run on massively parallel systems now being designed?

“Planetary Defense Workshop”

1995-teller.pdf: “Planetary Defense Workshop” (1995-01-01; backlinks)

“Old Legends”, Benford 1995

1995-benford-oldlegends.pdf: “Old Legends”⁠, Gregory Benford (1995-01-01; backlinks)

“Tacit Knowledge, Weapons Design, and the Uninvention of Nuclear Weapons”, MacKenzie & Spinardi 1995

1995-mackenzie.pdf: “Tacit Knowledge, Weapons Design, and the Uninvention of Nuclear Weapons”⁠, Donald MacKenzie, Graham Spinardi (1995; ⁠, ; backlinks; similar):

Tacit knowledge⁠, embodied in people rather than words, equations, or diagrams, plays a vital role in science.

The historical record of the development and spread of nuclear weapons and the recollections of their designers suggest that tacit knowledge is also crucial to nuclear weapons development. Therefore, if design ceases, and if there is no new generation of designers to whom that tacit knowledge can be passed, then in an important (though qualified) sense nuclear weapons will have been uninvented.

Their renewed development would thus have some of the characteristics of reinvention rather than simply copying. In addition, knowledge may be lost not only as a result of complete disarmament, but also as a consequence of likely measures such as a nuclear test ban⁠. [cf. Fogbank]

“The Astounding Investigation: The Manhattan Project's Confrontation With Science Fiction, Published in Analog Science Fiction/Science Fact”, Berger 1984

1984-berger.pdf: “The Astounding Investigation: The Manhattan Project's Confrontation With Science Fiction, published in Analog Science Fiction/Science Fact⁠, Albert I. Berger (1984-09-01; backlinks; similar):

In the spring of 1944, agents from the Manhattan Project’s security division interviewed Cleve Cartmill and John Campbell in the wake of Campbell’s publication of Cartmill’s short story “Deadline” in the March, 1944 issue of Astounding Science Fiction, in which U-235 had been separated from non-fissionable isotopes and was ready to be detonated in a functional bomb, whose details were described. As described, Cartmill’s bomb would not work; and it did not resemble the uranium bomb being built by the Manhattan Project. However, suspecting a leak from the Project (whose most difficult engineering problem with uranium was its separation into fissionable and non-fissionable isotopes), agents interviewed both author and editor. “Where did you get this idea?”

The incident has become part of science fiction folklore. Campbell spoke of it often before his death, and it is often referred to by members of the Analog Science Fiction/​Science Fact science fiction community, usually in the context of discussing the genre’s anticipation of actual scientific and technological developments. However, the military intelligence agents kept records of the investigation, records which have just been released in response to a request under the Freedom of Information Act. Seven separate documents, comprising some 39 pages of reports and memoranda filed under Cleve Cartmill’s name, show just how the people who were guarding the building of the real atomic bomb responded to the news that a disreputable pulp fiction magazine was apparently keeping pace with this recent and most secret research. Coincidentally, they shed light on Astounding’s fabled editorial practices just as World War II was disrupting the “stable” of famous science fiction writers John Campbell had assembled there between 1937 and 1941.

The Manhattan Project sought to provide internal security through compartmentalization. Only at the very top, and on a need-to-know basis, were the participants supposed to know what they were working on. Campbell and Cartmill had created a problem by naming what was intended to be unnameable: the near-term practical possibility of an atomic bomb. Campbell seems to have known something was up: “I’m stating fact, not theory”, he had written to Cartmill. Cartmill was afraid before he began writing that “Deadline” would do exactly what it did do: inadvertently call attention to a real bomb project. As contemptuous as Project security and the censor were of science fiction, they were also little afraid of precisely what Campbell’s science fiction did best: putting scattered bits of scientific knowledge together into a specific, concrete idea or device, and speculating on what that idea or device’s impact might be on the world at large. That kind of speculation represents a way of thinking distinctly at odds with those of bureaucracies like the Manhattan Project. The latter are often perfectly aware that two and two add up to four, but they equally often want to control the distribution of that news, for legitimate (as in this case perhaps) as frequently as for disreputable reasons.

So the affair represents more than just the anecdote which it has become. Cartmill’s letters reveal many of the constraints under which Campbell labored during the war; the affair as a whole shows the extremely casual way in which Campbell regarded so-called “voluntary censorship”. But that casualness, juxtaposed with the grim concern for control and fear of undue speculation on the part of the Project, marks an early and quite concrete example of the tension between the imagination engendered by science fiction and the concerns of the giant bureaucracies (governmental or private) which have so dominated scientific research and technological development since the end of World War II. It is probably belaboring Analog readers to remind them that this tension has furnished themes for more than a generation of science fiction stories.

“Possible Observation of Tachyons Associated With Extensive Air Showers”, Clay & Crouch 1974

1974-clay.pdf: “Possible observation of tachyons associated with extensive air showers”⁠, Clay, Crouch (1974; backlinks)

“Laser Compression of Matter to Super-High Densities: Thermonuclear (CTR) Applications”, Nuckolls et al 1972

1972-nuckolls.pdf: “Laser Compression of Matter to Super-High Densities: Thermonuclear (CTR) Applications”⁠, John Nuckolls, Lowell Wood, Albert Thiessen, George Zimmerman (1972-09-15; backlinks; similar):

Hydrogen may be compressed to more than 10,000× liquid density by an implosion system energized by a high energy laser. This scheme makes possible efficient thermonuclear burn of small pellets of heavy hydrogen isotopes, and makes feasible fusion power reactors using practical lasers.

[Very wrong.]

“The Legacy of Hiroshima”, Teller & Brown 1962

1962-teller-thelegacyofhiroshima.pdf: “The Legacy of Hiroshima”⁠, Edward Teller⁠, Allen Brown (1962-01-01; backlinks)

Deadline (science fiction story)