Everyone on board the starship watched as the hole slowly slipped into view, its gentle lavender radiance appearing like the dawn of a weak sun. It was an illusion that was broken soon enough as the satellite crept closer; the illuminated hole was small by any standards. Then the satellite passed over the rim, slowing to a relative halt. The magnetic flux in tandem with the gravity waves were strong enough to induce a detectable wobble, as if the satellite was floating on a sea. Anna did her best to counter the tiny vibrations, allowing the sensors to peer down carefully.
Four hundred kilometers below the hole, a curved lattice of immense dark strands were gliding slowly across the blue glow that came from deeper inside. As the satellite focused on the strands it became clear that the lattice was anything but a uniform hexagonal honeycomb. The interstices ranged from simple triangles up to twelve-sided grids with some of the strands curving them into near-ellipsoid geometries. The holes were the size of small countries, with strands up to a couple of hundred kilometers wide. One thing was obvious from the curvature and ponderous motion: the lattice was a sphere.
A thousand kilometers beneath it, a second lattice sphere was visible, also composed of dark strands, though this one had a more regular geography, mostly comprised of triangles and pentagons. It, too, was rotating, but in a completely different direction to the outer layer. And below that was a third lattice grid, with wider spacings. Its continent-long strands glowed a strong indigo, helping to create the pervasive glow. Its radiance was complemented to a large degree by streaks of amethyst light that came from underneath it, the indicators of a fourth lattice sphere spinning somewhere in the deeps. Exactly where was unclear; the third lattice appeared to be surrounded by some kind of lambent vapor.
“Son of a bitch,” Wilson whispered. Out of all the things he’d expected to see within the Dark Fortress, a kinetic sculpture bigger than planets was not high on the list. The scale of the barrier was already hammering at his beleaguered human senses. But that at least had been a projection, energy manipulated and folded on a stellar scale, while these lattice spheres looked resolutely solid. This was matter manipulated in quantities incomprehensible to Commonwealth technology. Yet the barrier creators had produced something that from a simple visual viewpoint was almost laughably mechanical, in the truest sense of the word. He wouldn’t be at all surprised now if they were to find gearboxes with cogwheels the size of moons driving the entire edifice. “Are those strands really solid?” he asked.
“I can’t tell,” Anna said. “The electromagnetic environment in there is playing hell with the satellite’s radar.”
“That much matter would coalesce under its own gravity,” Bruno said. “They have to be energy forms.”
“Not so,” Russell immediately claimed. “There’s nothing like a terrestrial planet mass in there. And their spin rates will keep them inflated.”
“Nonsense, they’d have to be metallic hydrogen to maintain their structural integrity under these conditions.”
“So? It’s metallic hydrogen. Apart from those glowing ones, I’d say they were exotic matter. There’s virtually no infrared emission coming from in there.”
“Is the outer shell complete?” Oscar asked. “I mean, is there a corresponding hemisphere on the inside of the barrier, or is this just some giant bearing groove for those lattice spheres?”
“Good question,” Tunde said. “Anna, can you focus the satellite telescope through those grids?”
“No, sir, no way,” she exclaimed. “That haze effect around the third sphere is like looking into a gas-giant cloudscape, and it gets thicker below it.”
“Like oil,” Oscar muttered. “It lubricates the gaps between the spheres.” He realized Tunde was looking at him and smiled an apology. “Just a thought.”
“Anna,” Wilson asked. “Will the satellite survive in there?”
She let out a long breath as she stared at the main image on the twin portals. “I don’t see why not, certainly as far down as the first lattice sphere, anyway. The sensor returns we’ve got show clear space that far in.”
“Okay then,” Wilson said slowly as a sense of real enthusiasm grew inside him. “Let’s do it.”
Anna launched a second Galileo-class satellite, flying it to the entrance hole at the top of what the crew now all called the Dark Fortress. Once it arrived, she sent the first satellite inside, using the second as a relay. As it descended toward the outermost lattice sphere, the energy surges around the satellite picked up noticeably. Eventually, Anna stopped trying to compensate. At that rate she would run out of fuel in a matter of hours. So she let the little craft wobble its way forward, blurring the visual sensor pictures. Every eighty kilometers or so she would stabilize it again, and run a quick check before allowing the vibrations to build up. There was nothing to see en route, the gap between the outer shell and the first grid sphere was empty, with the satellite sensors recording it as a hard vacuum.
When it was halfway there, one of the sphere’s massive struts slid underneath the hole, eclipsing the light pouring up from the inner lattice spheres. By now the crew were successfully recording the geography of the first lattice, and were making good progress charting the second. There seemed to be no logic behind the pattern. But predicting the times of the eclipses was now straightforward.
As the satellite grew nearer to the first lattice sphere, the radar return began to improve. “That’s odd,” Anna remarked as she stabilized the satellite once again.
“Problem?” Tunde asked.
“I’m using parallax to confirm the distance to the strut we’re heading for, but there’s a discrepancy between that and the radar return. Radar places it three klicks closer.”
“Maybe that optical haze effect is throwing the parallax reading?”
She shook her head. “Clear view. There is no haze around these struts.”
The discrepancy began to rise as the satellite closed in. Then they examined the magnetic flux around the strut, seeing the force lines warp like cyclone clouds around the surface.
After a long and heated conference with the rest of the physics team, Tunde said, “Whatever else it is, the outer lattice sphere has electro-repulsive properties. The radar pulses aren’t actually reaching the surface itself.”
“Can we take the satellite in and attempt a landing?” Wilson asked.
“I wouldn’t recommend it. That repulsion force would play havoc with the electronics. We’ll have to study it from a distance.”
The Galileo satellite spent two days hovering thirty kilometers above the first lattice sphere as it rotated slowly underneath. All of its sensors’ booms were fully extended, gathering up as much information as possible. Back on the starship, the physics team worked with the engineers to try to design a simple probe that they could drop onto one of the struts. Its circuitry was all optronic, using a laser for communication; sensors were extremely limited. But even studying its flight path as it neared a strut would tell them something.
Wilson, keen to expand the exploration of the Dark Fortress, authorized its deployment. A further two Galileo-class satellites were launched. Anna and Jean Douvoir had assembled a small team of controllers drawn from the pilot-qualified on board to help remote-fly the probes. Together, they steered the twin satellites through the entrance hole, and took them down toward the first lattice sphere. Anna maneuvered the lead one into the center of a pentagonal-shaped grid, and while Jean held the original satellite fifty kilometers above as a communications booster, she fired its ion thrusters, flying it straight in toward the second lattice sphere. As it passed through the level of the struts, electronic systems suffered repeated crashes. Thankfully the multiple redundancy architecture managed to keep the primary components on-line the whole time, constantly rebooting the failed units. It released the probe and carried on.