Von Neumann’s War

“Yeah, Ronny. We thought on that one a while and came up with making a cage out of radar absorbing material since we couldn’t use metals. It works pretty well, actually; we’re starting to use it in some places where we want shielding but don’t want to put in Faradays.” Roger pointed out some of the RAM materials inside a panel on the little spacecraft. Ronny’s eyebrows went up as he nodded. “We even used inefficient highly resistive carbon wiring on the major wiring harness from the panels to the power supply to reduce the need for metal there.”

“How do we get intel down from it?” Ronny asked while taking a more detailed look at the little spy satellite’s articulate components. “And what type?”

“Okay, it has a ten-centimeter glass optic aperture. We plan to orbit at LEO around four hundred kilometers so that will be about three meters per pixel on the ground. We’re gonna try a real ccd camera instead of film — well shielded from emissions. We also added a little commercial-off-the-shelf tip-tilt atmospheric distortion corrector in the optical path to clean up atmospheric scintillation and such. We should get good three-meter resolution images.” Roger paused for a second and pointed out the primary optic and the optical train of the telescope.

“I see,” Ronny nodded again. “Very interesting, fellas.”

“And this little gadget here,” Roger said, pointing to a black-composite material box with three small windows on the side, “is how we’ll get the data out. It’s a little diode laser communicator. We’ll download each time it comes over our ground stations in the U.S. and that means any place in the country with a meter aperture telescope or bigger will work. We’ve also built several portable ones.”

“Uh, Roger, how does the picosat know where the ground stations are if they’re mobile?” Alan asked.

“That is the beauty of it,” Roger said. “Tom has worked out the orbit model and each time we get a download it will get better. All we do is drive out in the path of the thing and send up a quick coded laser pulse train. The input to the optical system of the satellite detects it and turns on the downlink.”

“Won’t that tip off the aliens?” Ronny asked.

“Possibly, but we’ll send a weak signal and only for a few hundred microseconds. Besides, Ronny, this is laser. It’s monodirectional as hell. In fact, if we use a one-meter aperture beam-directing telescope on the ground, the laser spot size at the picosat including atmospheric spread of the beam will be less than four meters in diameter. We can spot the satellite passively with a telescope and fire the laser on boresight. And in case we can’t get the mobile units in the right place at the right time, the onboard system tracks landmarks of four ground-station locations. When the computer recognizes those landmarks it’ll link up automatically.”

“What type of bandwidth can we get?” Ronny asked.

“Well, we based the point-to-point laser communications system on an old Ballistic Missile Defense Organization program called the Space Technology Research Vehicle-2. That system could achieve 1.2 gigabits per second at eighteen hundred kilometers. We’ll only be at four hundred kilometers. So, rough calculations suggest about 2 to 3 gigabits per second. That’s about one 4 megapixel image per second. We’ll be in line of sight with the sat for about two minutes with each downlink, so, that’s over a hundred images per orbit and that’s about all the solid-state memory capacity the little picosat has anyway. We can also use them to send up a communication and downlink them back to a ground station. It’ll give us some minimal satcom capabilities back.” Roger watched for Ronny’s reaction, but wasn’t sure what he was thinking.

“I like it,” Ronny said, nodding somberly. “I mean, what’s the point of being the DDNRO if you don’t have any satellites? How are we going to put it up?”

“How are we going to put them up, is the right question, Ronny,” Roger said, raising one eyebrow and smiling.

“Them?”

“That’s right, them. We already have ten of them finished and ready to go.” Roger grinned from ear to ear.

“Very nice indeed!”

“They’re so small that we can put them all into two fairly small sounding rockets. John and Tom have already worked it out and one rocket is being put together out at Vandenberg and the other at the Cape right now.” Roger said.

“Why the two different launch sites?” Ronny wiggled uncomfortably in his paper jumpsuit.

“We’ll put half of them in staggered polar orbits and half of them in staggered standard orbits. We’ll maximize our coverage that way. For that matter, we’re moving the tech to make the sounders not on site into the redoubts. As long as the redoubts hold out, we’ll continue to have limited sat-com and ISR.”

“Good, Roger, good,” Ronny said, sighing tiredly. “We need the eyes. Although I’m almost afraid of what we’ll see. When do we launch?”

“Two weeks from today.”

“Good. Let’s hope it works. You got a backup plan if it doesn’t?”