The Reentry Series
Synthetic Meteor Showers
From the exhibition "Reentry: New York City, Studies for Synthetic Meteors", Eyebeam, NYC, Sept-Oct 2006:
View Flash videos or digital images from the HD video installation and DVD, "Studies for Synthetic Meteors V2.0 - New York City"
View Installation Photos, the Mission Profile Animation or an Interview with the Artist from the exhibition.

View HD video clips in Quicktime, Windows Media, or MPEG-2 formats from the HD DVD, "Studies for Synthetic Meteors V1.0".
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View Digital Images and Quicktime, Windows Media or MPEG-2 clips from the HD DVD, "Studies for Synthetic Meteors V1.0".


The Reentry Series uses multiple synthetic meteors to produce luminous, ephemeral drawings in the upper atmosphere. These drawings will persist for only seconds, at most minutes. The behavior of individual synthetic meteors will be similar to that of naturally occurring meteors. However their composition and configuration will be controlled, exhibiting various elementary geometric relationships which will seem obviously premeditated and systematic to any observer. That these are deliberate renderings will be inescapable. The Reentry Series is one of several proposed series of dynamic environmental works which involve the synthesis and aestheticised use of otherwise naturally occurring, very large scale, time dependent visual phenomena.


Space Shuttle Columbia Breakup
AP Photo/Jason Hutchinson
 
Since the beginning of space exploration the atmospheric reentry of man-made artifacts has created what could be considered synthetic meteors (1). The Reentry Series involves the deliberate creation of vast, ephemeral drawings using these reentry events. Historically, the pattern and timing of synthetic meteors has been inadvertent or has been determined as a side effect of other technical or scientific objectives or as the result of accidents. The tragic breakup of the space shuttle Columbia was certainly the most widely viewed of these events. Equally compelling but far less widely known were the tests of the MIRVed "Peacekeeper" ICBM nuclear missiles at Kwajalein Atol in the Pacific. ("MIRV" stands for Multiple Independent Reentry Vehicles"). In these tests up to ten simulated warheads effected simultaneous reentry, creating haunting geometrically organized synthetic meteor showers whose impact was magnified by the realization that this would be the visual precursor to nuclear annihilation.

These works will be executed using multiple, carefully timed, atmospheric reentries consisting of sacrificial payloads which become artificial meteoroids, each possibly from different trajectories and each forming a synthetic meteor which becomes a stroke in a visual composition. Such synthetic meteors can be created by one of two methods, commercial space launch of sacrificial payloads designed to reenter the atmosphere or the interception and de-orbit of extant orbital debris. The vehicle requirements for interception and de-orbit are substantially more complex than those for a simple launch and reentry, so it is almost certain that the former technique will be used, at least initially. It should be noted that the increasing volume of orbital debris has been identified as an environmental hazard, the remediation of which will certainly occur at some time, providing future opportunities to create these works. It may also be possible to mount these works around the planned "controlled demise", as it is called, of a orbital vehicle such as the Russian Progress robotic resupply rockets serving the International Space Station.

The work explores the large scale use of the environment, and the atmosphere in particular, as a medium for visual composition. A consequence of the activity is to highlight the extent to which humankind has impacted and has control over the environment. The work mimics the naturally occurring phenomena of meteors, which have historically been attributed with significant religious or supernatural import as signs or omens and demonstrates that these events can now be synthesized and manipulated at will. It is land art on a mega scale, exposing the degree to which we have altered and have the ability to further modify our environment. The work combines elements and properties of technological, environmental, and conceptual art.


SLG-118A Peacekeeper MIRVed ICBM
US Air Force Photo

 
Due to the nature and scale of the work, the use of advanced technology is essential. It requires the launching into space of significant quantities of material and even more difficult, the precise placement of that material on differing decaying orbital trajectories, designed to reenter the atmosphere at a precise time and place, in a specific pattern, creating a predetermined image composed of luminous reentry paths, a transitory drawing formed by a synthetic meteor shower. It is a form of robotic rendering on a vast scale.

Compositional Constraints

Unlike fireworks, to which a comparison is as inevitable as it is regrettable, synthetic meteors have significant constraints on the forms which may be created. Perhaps this is part of their attraction as a drawing medium. The limited repertoire of markings available is compelling and invokes an almost minimalist practice by necessity.

Stroke Shape
The most significant constraint is the fact that meteors are restricted to forming straight lines. While not necessarily obvious, the very high velocity and kinetic energy of meteors dictate this. Two other alternatives to simple meteors are available from astronomy, the cluster and the bolide. A cluster would involve a group of closely spaced meteors, the net effect of which would somewhat resemble a brush stroke as opposed to a single streak which would be more like a pencil line. The cluster will be investigated in future studies but presents problems in anticipating group behavior, i.e. collisions and other mutual interactions and so is considered less deterministic. A bolide is a very large meteor which actually explodes during reentry, shattering into numerous smaller meteoroids. Very dramatic no doubt, but virtually impossible to model or predict with current meteor understanding and therefore subject to minimal control. Also, bolides, due to their larger mass, usually result in ground collisions of larger fragments so must be excluded for reasons of safety. Perhaps when bolides are better understood they can be used compositionally.

Stroke Orientation
The orientation of meteor trails is determined by the trajectories of the meteors which are in turn governed by the launch profile and resulting reentry path. There are only two major variations, orbital and ballistic. Orbital is the most cost-effective method to obtain a reentry event, via deliberate decay of a "LEO" or low earth orbit trajectory. This technique is potentially more economic due to the possibility of "piggy-backing" on another project's launch. It would dictate velocities in the range of 8 km/s and a more or less zero flight path angle (the angle of the reentry trail with respect to the horizon). Thus for a single launch all of the meteors will be on an essentially horizontal plane with respect to the ground. This plane will be slightly inclined down in to the direction of travel. A major reason for constraining the meteors to be in this parallel plane is to insure they have similar reentry velocities. If the velocities are not well matched, the orbital decays will differ and the meteors will not reenter over same location. Most of the studies show this orbital decay reentry path. At a given observation location the meteor trail could extend from nearly horizon to horizon.


Peacekeeper ICBM MIRV test, Kwajelein Atol
US Air Force Photo

 
A ballistic launch profile involves sending the launch vehicle directly away from the earth in the fashion of an ICBM. The returning meteors can then exhibit very steep flight path angles. This is shown in only one of the studies, that for Albuquerque. Much higher reentry velocities, possibly as much as 30 km/s, can be obtained in this fashion. The final stages of a multistage vehicle can be turned 180 degrees with respect to their flight path prior to ignition, and fired back in the direction of the earth. This technique is rarely used but was done to test the reentry heat shield for the Apollo program as the returning crew module would be reentering at much higher than escape velocity. This is by far the more expensive approach however, almost certainly requiring a dedicated launch. Even with a ballistic launch the direction of all of the meteors is constrained to be in essentially the same orientation, largely parallel lines with some divergence. In order to achieve the intersecting sets of lines or grids shown in the studies, two separate launches are required, with the very rigorous requirement of achieving simultaneous collocated reentry.

The studies show a significant lateral separation between individual meteors. This so-called "cross-range" distance is difficult to achieve and requires significant expenditure of energy to deploy individual meteors with any significant separation. It is most probable that the meteor paths, instead of being truly parallel, will be divergent.

Stroke Color
It may not be apparent but there is the potential for a relatively broad chromatic palette when dealing with meteors. Naturally occurring meteors are often a pure white but can exhibit a wide range of colors including greens, reds, pinks, and yellows, virtually the entire spectrum. In addition, some meteors exhibit what is known as a persistent train, or trail, which can remain visible for minutes after the passage of the meteor. The color of this train can also vary, most typically being greenish or reddish yellow in color. Scientists are beginning to understand the chemical basis for the varying colors of meteors and their trains so it should be possible to exert control over the color of synthetic meteors by doping the artificial meteoroids with varying metallic compounds as with fireworks. The spectra of the allowable metallic ion transitions determine the color of the meteor trail as the metal atoms are ionized and then cool. The use of color and persistent trains are explored in the studies.


SLG-118A Peacekeeper, Deployment Module
A technician lowers the nose cone over the Peacekeeper final
stage or MIRV "bus". The conical shapes are the warheads
which the bus maneuvers to deploy at individual targets.
US Air Force Photo

 
A further possible variation on meteor color is to change the color of an individual meteor during the course of its travel. This could be accomplished by depositing different coloring materials in concentric layers. As each layer burned off the meteor would change color. This was discussed in some depth with leading meteor astronomer, Dr. Peter Jenniskens, and it was determined that the current state of meteor physics would make predictable and consistent behavior problematic. There is some uncertainly about ablation rates and uniformity, making the timing of the color changes uncertain. In addition, the meteorite would need to be imparted with substantial rotational velocity to insure uniform ablation around its circumference. This places a further burden of complexity on the deployment vehicle. Changing a meteor's color during the course of its path, while quite possible, is best reserved for future development when more is known about their behavior.

Stroke Timing
Since this is a time-dependent work, that would suggest the ability to stagger strokes over time. Again, the orbital or ballistic dynamics conspire against this, dictating essentially simultaneous reentry of the meteors from a given launch. Attempts to create staggered arrival times for meteors from the same launch involve either significant maneuvering of the deployment vehicle, requiring an unreasonable energy expenditure, or involve altering meteor velocity, requiring release during the boost phase of the launch. This would require an independent de-orbit thruster per meteor, again, an unreasonable complexity. The differing velocities would also make it extremely difficult to achieve arrival over the same geographical position, as an attempt to create a later arrival with a lower velocity would result in up range reentry. In short, all the meteors from a given launch are require to arrive more or less simultaneously.

A Limited Vocabulary
As can be seen, the available marking vocabulary for synthetic meteors is highly limited. While meteors share the luminosity and spectral character of fireworks they possess nothing of fireworks immense geometric diversity. This makes the medium interesting to the artist concerned with working in a restricted vocabulary as well as restricting the scope for commercialization. Thus the generation of synthetic meteors becomes an area of "pure" aesthetic practice.

Compositional Strategies
Within the confines of the limited vocabulary available, the compositions attempt to relate to the physical or geometric structure of the target site, whether built or natural; the rectilinear grid of Manhattan, the diagonals of the Bay Area, or the strong parallelogram shapes of Albuquerque. The compositions for other locales focus on specific places, the Capital Lawn and opposing structures of the Washington Monument and Capital building or the signature towers in Dallas. The minimalist compositions of the meteor showers attempt a site-specific relationship to the target locale, mirroring selective structures or highlighting others.


Peacekeeper ICBM MIRV test, Kwajelein Atol
US Air Force Photo
 
Cultural Associations of Meteors

Working with meteors demands acknowledgment of their powerful historical presence as omens and signs and a position with respect to that legacy. "...comets and meteors since time immemorial have functioned as symbols of change".(2) Many religions and cultures which are based on a linear concept of time (as opposed to the cyclical time perceived by Native Americans for instance), posit an end to worldly life, an apocalypse. Meteors figure prominently in many religious texts as precursors to such a "Rapture". The fixation with this supposed imminent end on the part of American Evangelicals highlights the disparity between popular culture and high culture in the US. Issues of theism or agnosticism aside, Apocalyptic and eschatological thought are rooted in the idea of linear history, an idea which firmly propelled modernism. In the light of postmodern thought apocalypse is either impossible or has already occurred, an idea which apparently does not have resonance with the Evangelical movement.

This work demythologizes meteors, removing their status as portents and acts of God, and instead incorporates them into the repertoire of artist's tools and materials. It is anti-apocalyptic in the sense that these works artificially create a portent of the apocalypse, and thereby strive to invalidate prophecies of apocalypse, revealing them to be archaic and obsolescent, historical religious fictions increasingly awkward to maintain in the light of advanced society. Should a global catastrophe occur, with the leading candidate perhaps being environmental disaster, it will be man-made, like these synthetic meteors. These works also serve to refute the idea of an apocalypse bringing an end to time. If interpreted as portents, these meteors are synthetic, and any concept of apocalypse is equally synthetic, an act of man, not god. It is ironic that the Kwajalein Atol ICBM tests, the reentry event most closely prefiguring these works to date, only serve to reinforce this position.

These works also function as a post-modern Apocalyptic Sublime. Both comets and meteors are consistent with Edmund Burke's doctrine of the Sublime and were a frequent subject in British art of the late 18th and early 19th centuries. The Reentry Pieces provide a literal realization of Danby's "Opening of the Sixth Seal", but without the repercussions, without any impending Apocalypse, without the ending. They are epic in scale but temporally transient and eminently reproducible. They support not the end of time, but the end of an idea of the linear development of art or culture.

These large scale environmental works also reflect on the development of electronic imaging. The strokes of the meteor's path faithfully mimic the first vector graphic displays. These vector displays drew lines of the desired orientation directly on the CRT phosphor, much like the stroke of a pencil, unlike contemporary raster displays which are scanned sequentially in a grid-like pattern. The short life of the meteor is very much like a single scan of the electron beam across the phosphor of a vector display. With CRT displays, the formation of a solid image is dependent on the continuous repetitive scanning of the image. It was common in early vector computer animation to scan the image only once per film exposure, with the single rapid pass of the electron beam over the face of the CRT having very much the same visual result as a meteorís rapidly fading trail due to the short persistence of the CRT phosphor. This suggests that synthetic meteors as a rudimentary form of atmospheric vector drawing might be the precursor to a more persistent raster atmospheric imaging method, perhaps formed by inducing ionization via laser or other means.


Leonids Meteor Shower (detail)
photo Pierre Martin & Michael F. Vasseur
 
Technology

The realization of these works will involve substantial planning and expense. Research is currently underway to determine the mass required of an artificial meteoroid to produce a given meteor visual magnitude in a night sky. This investigation is being done with the assistance of the NASA Orbital Debris Program Office. Initial estimates are as high as hundreds of kilograms of mass per synthetic meteorite. Preliminary investigation has indicated that a Pegasus air-launched three stage booster, developed by Orbital Sciences Corporation, might be the most cost effective launch vehicle. With a payload capacity maximum of about 400 kg and assuming a sacrificial payload mass of 100 kg per meteor, one vehicle launch could produce four meteors at a preliminary cost of approximately 2 million dollars assuming a rudimentary vehicle to disperse the individual payloads. These four meteors would exhibit effectively identical parallel orientations. To create drawings with differently oriented lines, for instance simple intersecting lines or a grid, would require a second near-simultaneous launch. The minimum lead time for a Pegasus launch is 22 months.

Interestingly, the LGM-118A Peacekeeper Missile (formerly known as the MX) would make an ideal launch vehicle for synthetic meteors. Capable of launching 10 reentry vehicles, each weighing 400 to 800 pounds, the final stage consists of the so-called "bus", a guidance platform capable of the precise individual release of each of the 10 reentry vehicles (originally nuclear warheads). The missiles are gradually being decommissioned with all of the 50 produced scheduled to be removed from service this year. Some are being converted to a satellite launcher role by Orbital Sciences, the Pegasus system supplier. Inquiries are underway to determine if this OSP-2 Peacekeeper variant still possesses the MIRV capability and the launch cost. The LGN-118A Peacekeeper program's cost was in excess of $20 billion.

A more detailed Implemetation Roadmap describes the steps required to develop the technology to mount the Reentry Series and includes updated mass requirements.


A red Perseid meteor photographed on August 9, 2002
photo Pierre Martin
 
Studies

Studies depicting synthetic meteor drawings are currently in preparation. The final works will almost certainly occur at night to minimize the mass required of the sacrificial payload for a given visibility. Depicting the meteor drawings against dark sky, at night, introduces obvious challenges to create a proper sense of space and scale. Some studies will employ a night sky and celestial bodies such as the moon, however, most studies will use night cityscapes as a backdrop both to site-specifically place the events as well as to provide a sense of scale. This also interrelates with the concerns of the Grid Switch Series. Computer video renderings of the reentry events are being composited into high definition video cityscapes and compiled as an HD DVD. Efforts are also underway to produce visualizations using the planetarium at the Rose Space Center of the American Museum of Natural History in New York.

While it might be desirable to execute the final works in the skies over cities for the obvious presence of an audience, there are severe obstacles to this. In addition to the potential for alarming the populace in a post 9/11 environment, extreme measures would have to be taken to assure that the sacrificial payloads were completely demised before reaching the ground. NASA now requires all space missions to undergo a risk assessment evaluation where the likelihood of physical harm to individuals from orbital debris which survives reentry is calculated using computer models. Even if it could be convincingly determined that the risks to those on the ground were minimal, the potential for alarm may militate overwhelmingly against that venue. Current practice is for the controlled demise of orbital vehicles to be conducted over remote unpopulated areas, such as the South Pacific.

"Studies for Synthetic Meteors V1.0"

View HD video clips in Quicktime, Windows Media, or MPEG-2 formats from the HD DVD, "Studies for Synthetic Meteors V1.0".
requires reasonably recent hardware, see specific requirements for each format

View Digital Images and Quicktime, Windows Media or MPEG-2 clips from the HD DVD, "Studies for Synthetic Meteors V1.0".

This is the first in a series of Reentry studies and which began in the Fall of 2004 and will be completed in the summer of 2005. This series of studies consists of high definition and standard definition video and digital prints. The Studies originate with a sequence of high resolution (8 Megapixel) digital camera images, typically 60 to 100, taken in rapid succession of the same scene, usually night cityscapes. These digital images are then subtly retouched and the meteor visualizations are rendered over them at a variety of resolutions, ranging from 3k x 2k pixels for digital prints to 1902x1080 and 1284x720 high definition video and finally 720x480 standard definition video. The typical video clip length is 20 seconds while digital prints are typically 20"x30".


Studies for Synthetic Meteors - San Diego
Still from HD Video Animation
 
The effects of atmospheric disturbance (the "shimmering" of distant lights or stars) are simulated by digital image processing of the original digital camera images. In addition, the night sky in the scene is usually darkened and a star field synthesized to create a ground for the simulated meteors. The meteors and shimmering are rendered at video frame rate while the digital image is updated every eight to ten frames. The result provides a final scene which is obviously different from simple recorded reality. The atmospheric effects and meteor trails are realistic but the scene itself "stutters" due to the 8 fps update rate of the original digital images. The final quality is slightly discordant in that "reality" is rendered less accurately than the simulated meteor events. Additionally, the meteor trails themselves are not rendered using 3D modeling software but are essentially sketched. Simple line drawings are made over the digital camera images. the endpoints digitized, and a drawing program was written to render these "meteor trails" with appropriate decay timing. All of the drawing occurs in the two-space of the original digital images so the perspective effects are very much "eyeballed" and show some hand. This satisfies the objective of not creating a perfect Hollywood-style digital rendering of the scene; these are, after all, studies. All software for the project was written by the artist.

The high definition video clips are each intended each to be viewed on individual HD displays. As an alternate, multiple clips from the same city could be presented on a single display. Consisting of 20 second loops, the meteor events typically last only a few seconds. The correct display is essential for proper presentation of the high resolution HD. As of this writing, there are only a handful of displays capable of the required resolution, which is 1920 pixels in width. The preferred presentation device is a wall-mounted LCD flat panel. Two 24 inch diagonal computer displays and one 45 inch diagonal digital television are the only current devices which are acceptable. Video projection would be equally desirable but the only 1920 video projector currently available is prohibitively expensive. A small number of laptops have acceptable displays as well as some CRTs, but these present difficulties in regard to installation.

The work may be released as a limited edition High Definition DVD, depending upon HD-DVD player availability. The "Blue-Ray" HD-DVD standard has been adopted and consumer players are expected in the fall of 2005. Pending the availability of HD-DVD players, a computer is required for HD playback. Several computer-based HD-DVD formats are available for distribution.

These studies have been shown to NASA offices and researchers as well as staff from the Rose Center for Space at the American Museum of Natural History in support of the project. It is intended to exhibit them in a variety of venues, fine art and otherwise, to attract additional support for the project.

Project Chronology

5/5/04, 3/2-4/05, 6/1-6/05, 7/19-20/05
Estancia, New Mexico

1) The reentry of man-made orbital objects creates luminous trails which are not strictly the same as meteors. Meteoroids (the celestial objects whose atmospheric reentry creates meteors) are usually very small, having the mass of a grain of sand. They are traveling at very high velocities, typically about 20 kilometers per second. Their reentry creates an atmospheric shock wave that produces a luminous plasma field which is nominally 50 meters in diameter. Manmade reentry objects have velocities less than 8 kilometers per second and produce somewhat less visible paths, consisting of a smaller luminous mantle, requiring a much greater mass to achieve the same apparent brightness. The physics of the reentry at these lower velocities are somewhat different than those of meteorites. However, in discussions with staff at the NASA Orbital Debris Program Office, the terms "synthetic meteors" or "artificial meteoroids" were deemed appropriate. Meteoroids which survive reentry to reach the earth's surface are called meteorites.

2) "Fire in the Sky: Comets and Meteors in the Decisive Centuries in British Art and Science" Roberta J.M. Olson and Jay M. Pasachoff, Cambridge University Press, 1998, p.3