The picture showing on the large wallscreen facing one end of the conference
table was a prototype habitat designed to test ideas and technologies for living
in space. It housed over twelve thousand people, in an immense torus more than
a mile in diameter. Six spokesthree thick, major ones alternating with
three thinner onesconnected the torus to a central hub structure. Part
of the image was shown in a cutaway to reveal miniature cityscapes and residential
areas alternating with multilevel agricultural sectors and parks. At intervals
around its exterior, the colony carried the Red Star emblem of the Soviet Union.
The Soviets had named it Valentina Tereshkovaafter the first woman
to go into space, more than fifty years previously. They claimed that it symbolized
the peaceful goals of their space program and would stand as a showpiece to
the world of what a Marxist economic system could achieve. Completion of "Mermaid,"
as the structure was code-named by the Western intelligence community, was targeted
for the following year, to coincide with the centenary celebration of the Russian
Gerald Kehrn, from the staff of the assistant secretary of defense for international
security, was more concerned about the colonys suspected hidden function,
however. He was an intense, restless man with a bald head and a heavy black
mustache, who radiated nervous energy and paced agitatedly below the screen
as he spoke. "Then, about a year ago, an East German defector appeared
in Austria, who claimed to have worked on construction of Tereshkova
from 2013 to 2014. He was brought back to the States, and in the course of further
interrogations described some of the hardware that hed seen, and in some
cases helped install."
Dr. Jonathan Watts, a civilian adviser with the decade-old US Space Force,
who had come with Kehrn from the Pentagon, interjected for Paulas benefit,
"Big-mother X-ray lasers. Nuclear-driven microwave pulses strong enough
to melt metal. A giant accelerator track buried inside the main ringwhat
youd use to feed batteries of matter-zappers." He tossed up his hands
and shrugged. His face was constantly mobile, changing expression with each
thought progression behind black, heavy-rimmed spectacles. "Other parts
of the place seemed to be for launching ejectable modules, probably fission-pumped
eggbuster lasers. And according to other reports, certain key parts of the structure
are double-shelled and hardened against incoming beams."
"Yet nobody else has seen a hint of all this," Paula remarked. "Enough
visitors have been through the place, havent they?"
"Just on the standard tour," Colonel Raymond said from his seat opposite
Watts. "They only see what theyre allowed to see. The place is over
three miles around, not counting the hub. Thered be enough room backstage
to hide the kinds of things were talking about."
Paula nodded and looked again at the image on the screen. Except for its inner
surfacethe "roof" facing the hubthe main torus was not
visible directly; it moved inside a tire-like outer shield of sintered lunar
rock which, to avoid needless structural loading, didnt rotate with the
rest of the colony. The shield was to exclude cosmic rays. Supposedly. Or was
that another part of the defensive hardening? The question had doubtless occurred
to other people too, so she didnt bother raising it.
In the center of the group, informally chairing the proceedings, was a broad-framed,
craggy-featured man with a dark chin, moody eyes, and gray, wiry, short-cropped
hair. He was Bernard Foleda, deputy director of the Pentagons Unified
Defense Intelligence Agency, and had arranged the meeting. The UDIA was essentially
an expanded version of the former Defense Intelligence Agency, now serving the
intelligence needs of the Space Force in addition to those of the traditional
services. He had said little since Paulas arrival, tending instead to
sit back for most of the time, watching and listening impassively. At this point,
however, he leaned forward to take charge of the proceedings again.
"Obviously this was something we had to check out." Foleda spoke
in a low-pitched, throaty voice that carried without having to be raised. "We
put a lot of people on it. To cut a long story short, we succeeded in recruiting
one of the people who worked on Tereshkovaa Russian, who was code-named
Paulas eyebrows lifted. "As a source? You mean you actually got
yourselves an inside man up there?"
Foleda nodded. "Luck played a part in it. He was someone wed had
connections with for a while. The details dont matter. Magician was an
electrical maintenance supervisor, which meant he moved about a lotexactly
what we wanted. He worked there for almost six months. But as you can imagine,
it wasnt the easiest place to extract information from. The snippets he
did get out to us were tantalizing. He indicated that hed collected a
whole package together, but he couldnt get it down to us. The security
checks on everybody who came back for leave or whatever were too strict. He
wouldnt risk it. But what he said he had up there sounded like dynamite.
We christened it the Tangerine file."
"Dynamite," Jonathan Watts repeated, tossing up his hands again.
"Weapons specks, pictures, firepowers, ranges, configuration data, parts
lists, blueprints, test data, installation dates . . . the works."
Foleda resumed, "Then somebody had an idea." He stopped and then
looked at Colonel Raymond. "It might be better if you explain the technicalities,"
Raymond turned his head toward Paula. "It involved the packet-header and
checksum protocols used in the Soviet communications link down from Mermaid."
Paula nodded. The terms related to data-communications networks.
In many ways, communications networks are like road systems: their purpose
is to move traffic quickly from one place to another with minimum congestion.
They therefore present similar problems to their designers. Speed is important,
of course, and so is safety, which means essentially the same in communications
as it does on highways: what arrives at a destination should bear as close a
resemblance as possible to whatever left the departure point.
Also important in both fields is using system resources efficiently, which
means avoiding situations in which some channels become choked while others
are not being used at all. Thus, morning commuters seek out alternative routes
for getting to work, which spreads traffic out over all the available roads,
to come together at a common destination. A standard technique for sending large
files of information from one computer to another through a communications network
works the same way. The sending computer breaks the file up into data "packets,"
which follow different routes through the network to the destination, with different
computers along the way deciding from moment to moment which way to route any
given packet, depending on the conditions at the time.
To guard against errors due to interference, equipment faults, or other causes,
the computer at the sending end uses the data content of a packet to compute
a mathematical function known as a "checksum," which it sends along
with the message. The receiving computer performs the same calculation on what
should be the same data and compares its checksum with the one that has been
sent. If they match, then the message is clear; or more precisely, the chances
against it are astronomically remote.
Raymond went on, "We figured out a way to transmit Magicians Tangerine
file down, using the Russians own Earthlink. Basically the idea was very
simple: rig the packets to carry a bad checksum, which means that the receiving
Soviet groundstation throws them out as garbage. But NSA is watchlisting the
mismatches. Get it?"
Paula was already nodding and smiling faintly. It was neat. When the checksums
failed to match, the receiving computer would simply assume that the message
it had assembled was corrupted, disregard it, and signal for a repeat transmission.
What Colonel Raymond was saying was that the checksums for the packets containing
the Tangerine file would be deliberately miscalculated. Therefore they
would, in effect, be invisible to the message-processing computers at the Soviet
groundstation. But the computers in the US National Security Agencys receiving
posts in Japan, Australia, Britain, and elsewhere, which eavesdropped on the
Soviets communications all the timeand just about everyone elses,
too, for that matterwould be programmed to look for just those mismatches.
Thus they would be able to intercept the information that the Soviet system
ignored. (It went without saying that it would be a simple matter to abort the
retransmission attempts for each packet after a couple of tries, to avoid getting
the system into a loop that would otherwise go on forever.)
"Tricky, though," Paula said. "Magician would have to get inside
the communications center up there."
"He was a maintenance supervisor," Raymond reminded her. "That
part was okay."
"Yes, but it would involve actually getting into the system software somehow,
and tampering with it. Was that really Magicians field?"
Foleda gave a heavy sigh. "Youve hit it, right on the nail."
Paula glanced around quickly. "I take it from the way were talking
that this didnt work out."
"We worked with what we had," Foleda said. "Magician wasnt
an expert on Soviet software. But we got the job down to what seemed like a
straightforward procedure, and he was confident he could hack it. . . .
But something went wrong. He got caught. The last we heard he was back in Moscowin
the Lubyanka jail."
"The Tangerine file wasnt transmitted?" Paula said.
Foleda shook his head. "Nothing ever came through."
"Presumably they got him first," Kehrn said, still below the wallscreen.
He came back to the table and sat down at last.
Paula looked away and gazed at the image of Valentina Tereshkova again
while she thought over what had been said. So, if it was a disguised battle
platform, in combination with the other weaponry that the Soviets were known
to have deployed in space, it would outgun everything the West had been putting
up for the past decade. But why did that call for the meeting in progress now,
and in particular her presence at it? Then it came to her suddenly what the
meeting was all about. She jerked her head away from the screen to look at Raymond
and Foleda. "That file is still up there," she said.
"Right on the nail, again," Foleda confirmed. "Magician managed
to get a message through to us after he was arrestedit doesnt matter
howsaying that as a precaution, he created a backup copy of the file.
Apparently the Soviets never found out about it." Foleda gestured at the
screen. "Its up there right now, inside a section of Mermaids
databank, stored invisibly under a special access code. We have that code. What
we dont have is somebody up there who would know how to break into a Russian
computer system and use it."
Paula stared hard at him as the meaning of it all became clear. They had risked
using a nonspecialist, and the gamble had failed. But by a small miracle, the
prize was still waiting to be claimed. This time they wanted an expert.
She swallowed and shifted her gaze from one to another of the faces staring
back at her questioningly. "Now wait a minute . . ."