This Old Rock (6 page)

••∞••

Liz went jogging. The track circled the small habitat—if you
ran spinward you were heavier. She ran spinward—punishing her body helped with
the frustration. They had enough power to divert the planetoid now, but no way
to couple that power efficiently to the planetoid. It would require engineering
a new reflector to couple the beam’s momentum to the planetoid. But if they
waited until they could get one installed, it would take so much power the
project would be compromised. The dilemma seemed to have no solution.

David, of course, would never understand that. Liz continued
going in circles, mentally and physically. Finally exhausted, she stopped at
the locker room, showered, dressed, and headed back to David’s quarters.

David wasn’t there.

••∞••

David stowed his Martin suit and a big duffel bag behind a
bulkhead then geckroed his feet by the airlock as the last shuttle from
Martin’s surface docked. His course was settled, but he wanted to make sure no
one else would be harmed. He waved to them as they came out of the access tube
and pulled themselves down the corridor, accompanied by robots pulling bags of
samples and gear. They all smelled of dust from the surface.

“Is everyone off the planet now?” David asked the last one
off, a stocky man named Ned Oh.

He nodded. “Everyone’s here and accounted for.”

“Very good. I will try to get back before departure for
Minot, but if not, go ahead without me; I may be some time, and can take this
shuttle back.”

Ned looked at David oddly, then smiled. “You? Late?”

David forced a smile. “The collision apparently will
not
be late, and there is still much to do.”

Ned patted him on the shoulder; the lack of an effort to
divert the planetoid had been a disappointment for all of them. They shook
hands and Ned followed his group down the corridor.

David boarded the shuttle and stowed his gear. Settling in
at the controls, he contacted the busy port manager. “I need to make a fast
trip down to the surface. There is a last minute discovery at a new ice lake.”

The man, tall and light-haired with a bushy mustache and an
easygoing manner, squinted and smiled. “Well now, someone might think you just
wanted to be the last one off the planet.”

David smiled back nervously and didn’t say anything. Let him
believe what he wanted.

The man shrugged. “Okay, it’s fueled and ready. No other
traffic, so you’re cleared.”

The trip down to the planet took four hours. The ice lake
actually existed; he landed on its shore. If nothing else, he would find out
one or two more things about this world. He pulled one of two boxes out of the
duffel bag and replaced it with a survival tent and a couple days’ worth of
rations. He carried the box down the ladder and set it down outside the
shuttle’s airlock. Then he went back up, opened the panel to the ship’s main
processor, and disconnected it. That should set some alarms going, he thought.

On his way out he touched the box and hesitated, going over
everything again. No, he had to do it this way. There could be only one way to
get him off the planet alive, and that would be to divert the planetoid. He
took a breath, threw the switch on the timer, climbed down the ladder, picked
up his gear, and headed for the lakeshore.

Ten minutes later, the blast severed his only way off the
planet.

They had not really listened before; perhaps they would
listen now.

Later, on a small rise, he looked out over the lake. At
early evening by local time, the scenery here, in one of the few places on
Martin’s surface not covered with ice, was breathtaking. The steep sides of the
caldera were a study in deep red and black, with glints here and there of
volcanic glass. The ground was cracked and brittle—he would have to watch his
step; getting himself killed too soon would defeat the whole purpose of this mad
exercise.

Would Liz or Mutori pull out the stops and divert the
planetoid? Or, would they let him be blown to smithereens along with the
planet? He looked at the still lake, reflecting the glowing crags of the
caldera’s rim. Was it really still, he thought, or was it, too, teaming with
life, every bit as deserving of saving as the damned, all too important, Black
Hole Project?

••∞••

Liz was deep in concentration on an idea that just might
work. Array construction robots in orbit about Canning were hurriedly
fabricating a huge net, a thousand kilometers in radius. A large magsail, meant
for a starship, would be attached to the net, along with several million tons
of ballast, weighted around the rim of the net. If everything went right, the
whole assembly could be pushed with planetary transport beams to intercept the
planetoid about a hundred planetary radii from collision with enough momentum
to cause it to graze Martin’s atmosphere instead of colliding directly. But it
would be very, very close.

Something was trying to get her attention. Amongst the
numbers and trajectories, a signal light was flashing.

“Yes?”

“It’s Ned. I’m at the door. I thought I should deliver this
news in person.”

That didn’t sound good. “Come in.”

One look at his face confirmed that he was the bearer of bad
news.

“Liz, have you heard about David?”

She shook her head.

“He’s gone to the surface of Martin, making a human shield
out of himself.”

“Oh… crap! I’m sorry, I should have seen this coming. He’s
never… he…”

“I didn’t see it coming either.”

“I’ll need to talk to Cyan.”

Ned nodded. “Let me know if there’s anything I can do.”

As he left, Liz touched the net.
Cyan, emergency, Cyan,
we have a problem,
she sent. The light speed delay was maddening.

What, Liz? What is the matter?

David has gone human shield on us.

Wait.

Human shield?

He’s gone down to Martin in hopes we’ll divert the beam
projector to save his life.

Wait.

You know him better than any of us, Liz. Can you talk him
out of it?

I’ll do what I can. I’ll get absolutely nowhere talking
on the radio. I’ll have to do this in person.

Wait.

The momentum exchange mesh—the big net—is almost ready,
Cyan
said.
Hopefully we can spread the push over the entire area and hold the
major pieces together. If we use BHP projectors, we can load less ballast and
launch it now, then give it a major push.

No! Keep the projectors on the impactor. We can’t risk
screwing with that. I’ll go down to Martin myself and try to bring David back.

Wait.

Liz, do you think that is wise? Much could go wrong.

Liz remembered how David had helped her stand up to DeRoot,
how he’d been at her side when things had seemed darkest, and all the
wonderful, sweet moments of lovemaking they’d shared.

Cyan, I owe him too much. I have to try. I’d never forgive
myself if I didn’t.

Wait.

I understand. You will take several robots, of course,
armed with tranquilizer darts; I will authorize the exception to the Asimovian
rules. I know you will try to get his voluntary cooperation first, but time is
short. And Liz we’ve been over David’s recent communications. Voice stress
analysis, word patterns, and other things. He doesn’t seem to be well.

Chaos! What?

People still occasionally got brain tumors, Liz knew. They
were quickly cured when detected, but they had to be detected first. Then there
was the stuff he was working with; the quarantine was very good, and the human
immune system should be totally lethal to anything that hadn’t evolved ways to
counter it. But there was still a chance. Deep in thought, Liz barely noticed
the light speed delay.

We don’t know without doing a scan and taking samples—it
could be strictly psychological, stress-induced. But I think it’s important to
know if he’s been affected by anything in the environment, because a layer of that
environment will be plastered all over this planetary system in a few years as
a result of impact debris. At any rate, he’s presenting the beginning stages of
classic paranoid schizophrenia, progressing rapidly. Also, whatever he does,
you should not blame him, or yourself. I know this is hard when it happens to
someone you love, but tragedies happen. If the worst happens, remember him as
he was. Finally, and I am very sorry to say this, but he may strike out
irrationally. Remember that if he does, it’s not him. But still, be very
careful. And remember that it is not always possible to fix everything. If it
gets too late, come back.

I will, Cyan. Thank you.

Could she hunt down David as if he were a zoo animal out of
his cage? Could she leave him to die? Did she have any choice?

••∞••

David found that he was off the net. The relays may have
been removed or someone may have thought that denying him access would give
them an advantage. That meant they were going to try to resolve this by force
instead of negotiation. His heart sank; that would cost several hours. No, he
thought, they might work the problem in parallel; even now some way to divert
the planetoid might be in the works, something that could be turned on or off
at the last moment.

Night fell. The planetoid was less than a day away, near the
ecliptic plane, coming posigrade. He looked to the west and found it easily—it
had a huge coma of gas, like a comet. The nucleus was already a small disk. It
would stay there, fixed among the stars. That was how one could tell if
something was going to hit you—the angles stay the same.

Very well. If they were going to try to force him off, they
would come with robots, sensors—the whole nine yards. They would succeed,
unless he could somehow anticipate them and strike first. He had dealt with
terrorists back in the Israeli defense force; he was on the other side now, but
he knew the territory. Maybe they would not anticipate that.

To get a surprise, he would have to make them think he was
here but actually be there. He took a reflective blanket and some line, then
climbed up a small lava dome until he could see the landing site. He built a
couple of small towers with flat volcanic rocks and anchored the top of the
reflective blanket to them. Then he anchored the bottom of it at about
forty-five degrees so it formed a kind of lean-to. He went back down and moved
his campsite until he could see the distorted reflection of the still-glowing
wreck of his shuttle in this jerrybuilt mirror. The radio in the emergency
stores had both infrared and radio frequency bands, as did the suit. He set it
up in sight of the mirror. If this worked, he’d be able to speak on infrared
from his suit, the infrared would reflect off the mirror to the emergency comm
pack, and his voice would come out on the radio from the campsite.

He took a second box from the duffel bag and headed for the
landing site.

Halfway there he keyed the infrared channel in his helmet.
“Hello everyone. Liz, Cyan. You know I am very sorry to cause you so much trouble.
You must also know that this is more important than your inconvenience, or even
my life, if it comes to that. You must do what you can to prevent the impact. I
must do everything I can to make you do that. I have no choice in this. I hope
you understand this. I am sorry.”

He heard his little speech on the radio as he said it; a
distracting echo, but it proved his system worked. Unless they had managed to
deploy a very sophisticated surveillance system on very short notice, they
should think he was at the campsite on the shore of the lake; he’d left a
heater on there, and the radio would be coming from there.

“David, this is Liz. I’m coming to get you. We’ve figured
out a way to divert the planetoid; a huge mesh net is on its way from Canning.
It will probably work, but if the planetoid breaks up in the net, some of it
may get through. It’s too dangerous to stay on the surface of Martin.”

David’s heart beat rapidly. There was hope. Then he thought
again. What proof did he have that anything was actually being done? They’d cut
him off from the net. She could be lying. Why not? She would do anything to
save her damn project.

“Liz,” he said. “That sounds very hopeful. Thank you for
making the effort, if it is true. But I must take the risk that it is not true,
or I give up all my leverage. Please go back and get me after the impact is
diverted.”

“David, you might be dead!”

“I know this. I have thought this through very carefully. It
is my choice.”

“David, I am coming to get you. That is my choice.”

He could think of nothing to say to that. He quickly covered
the distance to the landing site and hid himself in a broken lava tube near the
wrecked shuttle. None too soon; just as he settled in, he heard the sonic boom
of the approaching shuttle, and soon the glow of its engines lit up the
landscape. He watched the bullet-shaped vehicle’s landing gear extend as it set
smoothly down, the hatch side turned mostly toward him.

David agonized. But he would have to do what he had to do;
he had come too far to waver now. If Liz were lying to him, she had sealed her
own fate as well.

As soon as the shuttle landed and Liz had popped the hatch,
he opened his comm line. “Liz, my camp is on the shore of the lake, about ten
minutes walk from here, uh, I mean from where your shuttle is coming down.”

“I see it, David. Please come meet me at the landing site.
We’re doing everything we can.”

He shook his head automatically, even though she couldn’t
see him. “I cannot take that chance. I am sorry. If you want to talk, come to
the camp. We still have several hours.”

Liz didn’t answer him. The hatch swung open and she
descended, followed by three black circular robots hovering on their fans. He
could barely see them, but this close he could hear them.