Thinking of Dorrie reminded him of her gift. He opened it. It was a ceramic cup in harvest colors, ornamented with a cornucopia of fruits. The card said, “This is a way of telling you that I love you.” And it was signed Dorrie.

All of Torraway’s signs were stable now, and we were getting ready to phase in the mediation circuits.

This time Roger was well briefed. Brad was with him every hour — after taking a large share of the President’s ass-kicking, he was chastened and diligent. We deployed one task force to oversee the phasing-in of the mediation circuits, another to buffer the readout-readin of data from the 3070 in Tonka to the new backpack computer in Rochester, New York. Texas and Oklahoma were going through one of their periodic brownouts just then, which complicated all machine data handling, and the aftereffects of the flu were still with the human beings on the staff. We were definitely short-handed.

Moreover, we needed still more. The backpack computer was rated at 99.999999999 percent reliable in every component, but there were something like 108 components. There was a lot of backup, and a full panoply of cross-input paths so that failure of even three or four major subsystems would leave enough capacity to keep Roger going. But that wasn’t good enough. Analysis showed that there was one chance in ten of criticalpath failure within half a Martian year.

So the decision was made to construct, launch and orbit around Mars a full-size 3070, replicating all the functions of the backpack computer in triplicate. It would not be as good as the backpack. If the backpack experienced total failure, Roger would have the use of the orbiter only 50 percent of the time — when it was above the horizon in its orbit and thus could interlink with him by radio. There would be a worst-case lag of a hundredth of a second, which was tolerable. Also he would have to stay in the open, or linked with an external antenna otherwise.

There was another reason for the back-up orbiter, and that was the high risk of glitches. Both the orbiting 3070 and the backpack were heavily shielded. Nevertheless they would pass through the Van Allen belts at launch, and the solar wind all through their flight. By the time they got to the vicinity of Mars the solar wind would be at a low enough level to be bearable — except in the case of flares. The charged particles of a flare could easily bug enough of the stored data in either computer to critically damage its function. The backpack computer would be helpless to defend itself. The 3070, on the other hand, had enough reserve capacity for continuous internal monitoring and repair. In idle moments — and it would have many idle moments, as much as 90 percent of its function time even when in use by Roger — it would compare data in each of its triplicate arrays. If any datum differed from the same datum in the other arrays it would check for compatibility with the surround data; if all data were compatible, it would examine all three arrays and make the one aberrant bit conform with the other two. If two did not conform, it would check against the backpack if possible.

That was all the redundancy we could afford, but it was quite a lot. On the whole, we were very pleased.

To be sure, the orbiting 3070 would require a good deal of power. We calculated the probable maximum draw against the probable worst-case supply of any reasonable set of solar panels, and concluded that the margin was too thin. So Raytheon got a preempt order for one of its MHD generators, and crews went to work on Route 128 to modify it for space launch and automatic operation in orbit around Mars. When the 3070 and the MHD generator arrived in orbit they would lock to each other. The generator would supply all the power the computer needed, and have enough left over to microwave a useful surplus down to Roger on the surface of Mars, which he could use both to power his own machine parts as needed or for whatever power-using equipment he might like to install.

Once we had completed all the plans we could hardly see how we had thought we could get along without them in the first place. Those were happy days! We requested, and were promptly given, all the reinforcements we needed. Tulsa went without lights two nights a week so we could have the energy reserves we needed, and Jet Propulsion Laboratories lost their entire space-medicine staff to our project.

The read-in of data proceeded. Glitches chased themselves merrily around both new computers, the backpack in Rochester and the duplicate 3070 that had been rushed to Merritt Island. But we hunted them down, isolated them, corrected them and were keeping right on schedule.

The world outside, of course, was not as pleasant.

Using a home-made plutonium bomb made out of materials hijacked from the breeder reactor at Carmarthen, Welsh nationalists had blown up the Hyde Park Barracks and most of Knightsbridge. In California the Cascade Mountains were burning out of control, the fire-fighting helicopters grounded because of the fuel shortage. An exploding epidemic of smallpox had depopulated Poona and was already out of control in Bombay; cases were being reported from Madras to Delhi as those who were able fled the plague. The Australians had declared Condition Red mobilization, the NPA had called for an emergency meeting of the U.N. Security Council, and Capetown was under siege.

All of this was as the graphs had predicted. We were aware of all of it. We continued with our work. When one of the nurses or technicians took time to worry, he had the President’s orders to reassure him. On every bulletin board, and placarded in most of the workrooms, was a quote from Dash:

We didn’t need the reassurance, we knew how important the work was. The survival of our race depended on it. Compared to that, nothing else mattered.

Roger woke up in total blackness.

He had been dreaming, and for a moment the dream and the reality were queerly fused. The dream had been of a long time ago, when he and Dorrie and Brad had driven down to Lake Texoma with a few friends who owned a sailboat, and in the evening they had sung to Brad’s guitar while the huge moon rose over the water. He thought he heard Brad’s voice again… but he listened more closely, his brain clearing from sleep, and there was nothing.

There was nothing. That was strange. No sound at all, not even the purrs and clicks of the telemetry monitors along the wall, not even a whisper from the hall outside. However much he tried, with all the enhanced sensitivity of his new ears, there was no sound at all. Nor was there light. Not in any color, not anywhere, except for the dullest of dim red glows from his own body, and a glow equally dull from the baseboards of the room.

He moved restlessly, and discovered he was tethered to the bed.

For a moment terror flooded through his mind: trapped, helpless, alone. Had they turned him off? Were his senses deliberately blacked out? What was happening?

A small voice near his ear spoke again: “Roger? This is Brad. Your readouts say you’re awake.”

The relief was overpowering. “Yes,” he managed. “What’s going on?”

“We’ve got you in a sensory-deprivation environment. Apart from my voice, can you hear anything?”

“Not a sound,” said Roger. “Not anything.”

“How about light?”

Roger reported the dim heat glow. “That’s all.”

“Fine,” said Brad. “Now, here’s the thing, Roger. We’re going to let you work in your new sensorium a little bit at a time. Simple sounds. Simple patterns. We’ve got a slide projector through the wall over the head of your bed, and a screen by the door — you can’t see it, of course, but it’s there. What we’re going to do — wait a minute. Kathleen’s determined to talk to you.”