"Hollywood,” the fox repeated. Again he was motionless, no doubt having one of those life-assessing moments. Lifting his head, at last, he faced me. “How can you be so certain she did it?"
"She tried to kill us, too.” I explained how the vixen had tunneled into Champion's stall and how we discovered her expired human meat suit below the phony National Park Information Center. He shook his head at last, got up on all fours, turned toward the back of the chamber, jumped up on a ledge, and seemingly vanished into the rock. We heard his voice say, “This way."
I moved up to where Quartermain seemed to have vanished and saw a shelf of stone. Just beneath it was an opening that was impossible to see unless one was right up on it. “This way, Shad."
"I found something,” he said.
I moved back down and crossed the water to where Shad's light was illuminating something the size of a dinner roll that looked sealed in waterproof plastic. “Is that the missing portable image imprinter?"
"She tried to hide it in the water. The vixen carried it down here holding the plastic bag in her mouth. Tiny, sharp, little teeth. Water got in the bag. We'll be able to match Wurple's bio to the bite mark impressions."
"We'll need the tracked mech to bring it out, Shad. Before we do that, call it in to Police Constable Lounds for the arrest. That ought to raise his esteem in the park constabulary."
"I'd love to see his boss's face when he finds out his case fell apart."
"Let's get to Quartermain's den. Your old roommate is about to give up his mate."
* * * *
"Why did you kill Miles?” we heard Quartermain demand as Shad and I came out of the tunnel into a chamber where the only illumination was provided by our lights.
"I didn't mean to at first,” answered the vixen's tearful voice. She looked at us, her eyes wide. Looking at Quartermain she said, “Really I didn't. I'd hoped to frighten him out of the—Oh, I can't look at you and tell you this!"
"It doesn't matter. I'm sending you over,” said Quartermain. He seemed to laugh to himself—at himself—then he glanced at Shad's micro and hung his head. “Yeah. I'm sending you over,” he repeated as he slunk out of the chamber.
She turned from watching Quartermain's departing tail, and laughed nervously. “Oh—he frightened me for a moment. He was joking. That's it. After all, I'm carrying his babies. He was joking, wasn't he?"
"Don't be silly,” said Shad in that special Bogart voice of his. “You're taking the fall. You killed Miles and you're going over for it."
"How can you ... how can he do this to me?” She broke down and began a really irritating series of whines.
"Listen,” said Shad after awhile. “This won't do any good. You'll never understand me, but I'll try once and then give it up. When a fox's partner's killed, he's supposed to do something about it. It doesn't make any difference what the fox thought of him, he was your partner and you're supposed to do something about it. And it happens they're in the fox hunting business. Well, when one of your fox hunters gets killed by a fox, it's bad business to let the fox get away with it. Bad all around. Bad for every fox hunting operation everywhere."
Shirley Wurple didn't know her next line from The Maltese Falcon, which left Shad with nothing left to say.
The vixen looked at me and said, “What if I run? You two little pocket pips couldn't stop me."
"No, we couldn't,” I answered. “In Houndtor Down Lodge this instant, though, equipped with the best riding stock and guided by the most competently trained hounds in the world, is an assembly of the most proficient and fanatical fox hunters in the world. You've never run before the hounds, doctor. You don't know how. I fear in a matter of minutes you and your unborn cubs would be cornered and most likely torn to pieces. Why not let a judge and jury decide your fate?"
"I can run faster than you can move. My human body can—"
"Your human body is dead, Dr. Wurple,” said Shad.
Her eyes grew wide as she faced me.
"Carbon monoxide poisoning from your generator,” I explained. “There was nothing we could do.” I could see the defeat in her face as I turned away, sad for her.
* * * *
She cooperated in exiting the burrow once PC Lounds arrived to caution her and make the arrest. He put her in a dog cage and drove off with her in the electric. There wasn't anything we could say to console Archie Quartermain. All we could do was to give him the number of a facilitator for an amdroid grief group, see to it that DCI Stokes released Lady Ida Bowman with all due apologies, and head back to Exeter, the sun actually making it through the clouds for a minute before a new front came in and the rainfall resumed.
While we rode off into the truncated sunrise, I asked my new partner, “How would you like to be on that jury, Shad? He was the fantasy love of her life, and the price of her union with him was she'd have to remain helplessly by while he was killed over and over again. What to do?"
"We just catch ‘em, Jaggs. We don't cook ‘em."
"Indeed, Shad. Too bad we resolved things so quickly, though. I really wanted to meet Dorothea Tay. Back in the dim reaches of time, I fear she was my childhood heartthrob."
After a moment of silence, Shad said, “Speaking of old movies, The Maltese Falcon was a script Archie and I had memorized front to back. ‘I'm sending you over.'” He chuckled and said with Humphrey Bogart's voice, “'When a fox's partner's killed, he's supposed to do something about it.'” He glanced at me and said in his own voice, “Why did you let me go on like that?"
"My dear chap, I never would have dreamt of deprivin’ you of your moment of triumph."
He frowned, regarded me with one dark eye, and said, “The Scarlet Pimpernel, Anthony Andrews vid remake, nineteen eighty-two."
"Quite right,” I said as I beamed at my new partner. “Excellent."
Copyright © 2006 Barry B. Longyear
[Back to Table of Contents]
SCIENCE FACT: THE INTERSTELLAR CONSPIRACY by Les Johnson & Gregory L. Matloff
Interstellar travel is (no pun intended) a long way off—but the first steps may already be underway.
What if...
If we were designing a human-carrying starship that could be launched in the not-too-distant future, it would almost certainly not use a warp drive to instantaneously bounce around the universe, as is done in Isaac Asimov's classic Foundation series or in episodes of Star Trek or Star Wars. Sadly, those starships that seem to be within technological reach could not even travel at high relativistic speeds, as does the interstellar ramjet in Poul Anderson's Tau Zero. Warp speeds seem to be well outside the realm of currently understood physical law; proton-fusing ramjets may never be technologically feasible (Matloff, 2000). Perhaps fortunately in our terrorist-plagued world, the economics of antimatter may never be attractive for large-scale starship propulsion (Mallove and Matloff, 1989).
But interstellar travel will be possible within a few centuries, although it will not be as fast as we might prefer. If humans learn how to hibernate, perhaps we will sleep our way to the stars, as do the crew in A. E. van Vogt's “Far Centaurus.” However, as discussed in a landmark paper in The Journal of the British Interplanetary Society, the most feasible approach to transporting a small human population to the planets (if any) of Alpha Centauri is the worldship (Bond and Martin, 1984). Such craft have often been featured in science fiction. See, for example, Arthur C. Clarke's Rendezvous with Rama and Robert A. Heinlein's Orphans of the Sky.
Worldships are essentially mobile versions of the O'Neill (1974, 1977) free-space habitats. Constructed mostly from lunar and/or asteroidal materials, these solar-powered, multi-kilometer-dimension structures could house ten thousand to one hundred thousand humans in Earth-approximating environments. Artificial gravity would be provided by habitat rotation, and cosmic-ray shielding would be provided by passive methods, such as habitat atmosphere and mass shielding, or magnetic fields (Johnson and Holbrow, 1977). A late twenty-first century space-habitat venture might support its
elf economically by constructing large solar-powered satellites to beam energy back to Earth.
But how might a multi-billion-kilogram space habitat be propelled if its inhabitants choose to attempt an interstellar migration without antimatter, ramjets, or space warps? A landmark paper by Dr. Anthony Martin, who currently edits The Journal of the British Interplanetary Society, addresses this issue (Martin, 1984). Gravity-assist maneuvers using the giant planets may be used to fling a spacecraft toward the stars, as has been demonstrated by our first extrasolar probes, Pioneer 10/11 and Voyager 1/2. Unfortunately, this is a time-consuming technique—about seventy thousand years would be required by the fastest of these vehicles to reach Alpha Centauri, if any of them happened to be traveling in that direction.
If interstellar migrants intend to cross the forty trillion kilometers between the Sun and Alpha Centauri within a millennium or so, there are only two propulsion systems that currently appear promising. These are nuclear-pulse propulsion and the ultra-thin solar-photon sail unfurled as close to the Sun as possible.
The nuclear-pulse rocket, which is derived from the DoD/NASA Orion Project of the 1960s, would ignite nuclear or thermonuclear “devices” as close as safely possible to the spacecraft. A properly shielded combustion chamber would reflect explosion debris, thereby propelling the spacecraft by Newton's Third Law. As demonstrated by Dyson (1968), a thermonuclear Orion could propel a worldship on a voyage of less than 1,300-year duration to Alpha Centauri, if the world's nuclear powers agreed to sacrifice most of their thermonuclear arsenals. Fat chance!
A somewhat sanitized nuclear-pulse starship, Project Daedalus, was studied by a British Interplanetary Society team during the 1970s (Bond et al, 1978). Daedalus would have been propelled by electron-beam-initiated explosions of fusion micropellets. The fusion fuel of choice was a combination of deuterium and helium-3. Although theoretically capable of accelerating a large starship to 10 percent of the speed of light (0.1c), the Daedalus concept was hampered by the terrestrial rarity of helium-3. Unless we can mine this isotope from a cosmic source—the solar wind, lunar regolith, or giant-planetary atmosphere—Daedalus would not be a practical solution to starflight.
Another disadvantage to nuclear-pulse propulsion is scaling. No matter whether the payload is a billion-kilogram worldship or a 10-kilogram microprobe, the propulsion system will still be enormous.
The remaining interstellar option—the solar sail—is quite scalable, which is a good thing for the budgets of present-day sail experimenters. The concept of interstellar solar sailing was developed independently by two teams in the late ‘70s and early ‘80s. Chauncey Uphoff of NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California, considered this as an alternative propulsion method for the NASA Thousand Astronomical Unit (TAU) extrasolar probe study, but his work was only incorporated into that study as an “unpublished memo” (Jaffe et al, 1980). In a series of papers beginning in 1981, Gregory Matloff and Eugene Mallove presented various aspects of this propulsion option in the peer-reviewed literature (Matloff and Mallove, 1981, 1983).
As described in the cited references, an interstellar solar sail would approach the Sun as closely as possible with the sail either directed away from the Sun or otherwise protected from solar radiation pressure prior to perihelion. At perihelion, the sail would be partially or fully unfurled and exposed to sunlight, accelerating the solar sail by the radiation pressure of solar photons.
Analysis revealed that if ultra-thin (20-30 nm), space-manufactured, all-metal sails are used with perihelion passes that are as close to the Sun as physically possible (within about 0.04 AU of the Sun's center), and if the cables joining sail to payload approximate the tensile strength of an industrial diamond, even large payloads could be accelerated in this manner towards Alpha Centauri on trajectories requiring about one thousand years. After acceleration (at 1 g or higher), cable and sail could be wound around the habitat section to provide extra cosmic-ray shielding. Assuming the space-manufactured sail has a very long lifetime in the galactic environment, sail and cables could also be used again for deceleration at the destination star system (Matloff, 2000a).
Of course, we could not construct such a starship today. But a NASA project—the In-Space Propulsion (ISP) Technology Project—is gaining knowledge about sail films and structures, high-acceleration operation of gossamer structures in space, and the application of ultra-thin filaments that could lead to the development of sail cables. Since this capability is being developed to support modestly funded science missions, not voyages of interstellar colonization, the work of ISP may be thought of as an “interstellar conspiracy,” by which means humanity is developing an interstellar capability almost as an afterthought.
What is...
The In-Space Propulsion (ISP) Technology Project?
Managed at the NASA Marshall Space Flight Center in Huntsville, Alabama, the In-Space Propulsion (ISP) Technology Project is an outgrowth of the NASA “Interstellar Initiative” of the late 1990s. The initial ISP research concentration was on propulsion systems, such as current-technology Earth-launched solar sails unfurled 0.2—0.3 AU from the Sun, that would enable in situ exploration within a few hundred AU of the Sun on missions of a few decades duration (Johnson and Leifer, 2000). The purview of ISP has since been expanded to include propulsion systems that could enable or enhance all scientific space missions under consideration by the NASA Science Mission Directorate with destinations above low-Earth orbit (LEO).
Most technologies considered by ISP researchers are approaching flight readiness, although some attention in the past was devoted to more speculative, higher-risk propulsion concepts with potentially high payoffs, such as plasma sailing (Lai, 2004). A prioritization system has been developed by ISP to match in-space propulsion technologies with planned or proposed space missions in an effort to pace their development so they will be ready when needed.
Six in-space propulsion technologies dominate the ISP research spectrum. These include advanced chemical propulsion, advanced solar electric propulsion (SEP), aerocapture, solar photon sails, solar thermal propulsion (STP), and tethers.
Advanced Chemical Propulsion
Today's chemical rockets are approaching their practical and physics-driven limits. To maximize the scientific return from space probes designed to descend for landings on planetary surfaces or ascend from such surfaces to return samples to Earth, a number of improvements to chemical rocket technology are under study and development.
Goals of this research include increased performance and safety, reduction in propellant storage uncertainties, and improved system efficiency. As well as advanced chemical fuels, researchers are investigating improvements in cryogenic fluid management to improve the efficiency and handling of cryogenic components. Another high-payoff improvement would be the reduction of the mass and complexity of structures utilized to carry and transfer propellants. While advanced chemical propulsion systems would not be applicable to interstellar voyages, this evolutionary technology could enable more ambitious exploration of our Solar System.
Advanced Solar Electric Propulsion (SEP)
Also called the “ion drive,” solar electric propulsion works by using collected solar energy to first ionize and then accelerate propellants to exhaust velocities considerably higher than the 4.5 kilometers per second (km/sec) exhaust velocity of state-of-the-art chemical fuels. The exhaust velocity of the ion engine aboard the highly successful NASA Deep Space 1 probe was about 30 km/sec. The best SEP propellants are inert gases such as xenon and krypton.
Although high velocities are possible using SEP (and its nuclear cousin NEP), ion drives have low thrust and will always be utilized in space, never for Earth-to-orbit transportation. A number of improvements are planned to increase the performance of future SEP-propelled interplanetary probes.
One approach seeks to reduce the complexity and increase the operating lifetimes of SEP systems. To meet these needs, laboratory demonstrations of Hall-effect thruster
s are currently underway. This will allow efficient SEP operation on missions significantly more challenging than previously flown.
Researchers are also working on methods for increasing the exhaust velocity of next-generation SEP to around 50 km/sec. Because of the higher exhaust velocity, fuel requirements for a given mission using next-generation SEP will be reduced, which also promises to increase the scientific payload mass.
Increasing the efficiency of ion thrusters will result in longer-duration SEP missions farther from the Sun, some of which may serve as interstellar precursors.
Aerocapture
Aeroassist technology has been used since the early days of space travel. Every Earth-returning capsule and the space shuttle have applied the atmosphere as a drag brake and thereby greatly reduced the requirement for reentry fuel.
A related technology is aerobraking, whereby a spacecraft in an elliptical orbit around a planet with an atmosphere dips into that planet's atmosphere repeatedly, to gradually circularize the orbit and decrease the spacecraft's distance from the planet.
An interplanetary spacecraft will be able to use the new technology of aerocapture to become a satellite of a planet by performing a single pass through its atmosphere.
Current aerocapture research under ISP emphasizes integrating a low-mass aeroshell with a thermal protection system and the development of aerocapture instrumentation. Various advanced aerodynamic decelerators are under consideration for aerocapture missions, including rigid structures, trailing and attached ballutes (a ballute is a combination balloon and parachute), and inflatable aeroshells. Figure 1 illustrates the different technology approaches for aerocapture.
* * * *
* * * *
Aerocapture is a fast maneuver, with a spacecraft decelerating from interplanetary to orbital velocity within one orbital pass. Decelerations in some cases are higher than 1 g, and knowledge of the destination planet's atmospheric profile is required to optimize the aerocapture trajectory.
Analog SFF, November 2006 Page 8
