Solar Express

by L. E. Modesitt Jr.

  “As if it were an impenetrable hull.”

  “Your words, not mine. But I’d tend to agree.” The colonel paused. “How would you like to go take a look at it?”

  “You want an armed FusEx ship … because of the Sinese? What about scientists?” Tavoian’s eyes went back to the screen.

  “First, we have to get someone there, to make certain they don’t monopolize it. We aren’t sure what it is, and it’s hard to get that large a commitment of resources without that. The other problem is that there’s no ship immediately available with sufficient habitability to support a team and all they need for more than a week or so. Possibly a month. We also have to gather a team and get them together. All that takes time that we don’t have.”

  “So … a ship with one man and an array of AI devices that can investigate and probe immediately. With enough arms to keep the artifact open to us.”

  “Precisely.”

  “With a pilot who has no significant other and a talent for AI.”

  “That would be useful.”

  “It sounds like a minimal resources mission,” ventured Tavoian.

  “Not quite minimal, but close. We’re not skimping on fuel, drives, or habitability. We’ve also beefed up the radiation shielding because of the time you’ll be out there, but there’s not enough time to develop specialized equipment, not if we want to look at the object before it grazes the sun.”

  “You’re gambling that there’s something of value there.”

  “Wouldn’t you, Captain?”

  Rather than comment verbally, Tavoian let a wry smile appear. “What if the Sinese reach it before we do?”

  “That’s unlikely, but the pilot’s mission is not to forbid their exploration, but to allow ours when a team arrives, and to set out as many AI devices to discover what those devices can determine in the meantime.”

  “What about communications?”

  “We won’t restrict your comm. The pilot will have full comm, through targeted encrypted burst.”

  “Including personal messages?”

  “After review … yes.”

  “When would this … mission begin?”

  “Tomorrow morning. We’re awaiting additional AI equipment. Are you interested?”

  “How could I not be?”

  “There’s a definite element of danger. You’ll have to match inbound velocity, and you may have to stay with the object for quite some time, depending on what you discover.”

  “Weeks?”

  The colonel barked a laugh. “More like two months, if necessary. Theoretically, if any FusEx had the fuel capacity, it could reach the object in four days of constant one-gee acceleration and then constant decel. The ship is having additional Hel3 tanks installed, but not that kind of capacity, and the drives can’t maintain that acceleration near long enough. There are also habitability concerns…”

  “No one has spent months in a FusEx, only a few weeks.”

  “Five weeks at most with three people. The systems weren’t strained.”

  Tavoian understood the unspoken concern. No one knew how long the systems would remain unstrained. They weren’t designed the way lunar or satellite systems were.

  “The other aspect is that if you stay with the object until it nears the orbit of Mercury, perhaps somewhat longer, you’ll have enough fuel to depart, but there would be no way for any ship to reach you if matters turned black.”

  Tavoian frowned. That didn’t make sense.

  “Think about it. What’s the maximum safe continuous thrust at one gee.”

  “Two hours. Two and a half under optimal conditions.”

  “That thrust will give you a terminal velocity just over seventy kays per second … I can’t do all the math in my head, and I’m not about to ask the AI to calculate for reasons I trust you understand, but even with an acceleration and drive rest cycle, and given fuel limitations, it would take a FusEx nearly seven days at speed to reach where you were. But by the time this object nears Mercury, it will be traveling at somewhere in the range of sixty kays per second, accelerating to as high as 250 by the time it reaches perihelion … a real solar express.”

  “I get the picture, sir. I’d be at perihelion with the object before any ship could get close.”

  “There’s also the small problem that the solar escape velocity much inside the orbit of Mercury would test the capability of any of our burners, except on an elliptical flyby, and that doesn’t provide the best odds for a rendezvous.”

  Tavoian understood that as well. A tangential course from the object might be possible, even halfway between Mercury’s orbit and the sun … but it wasn’t something he’d want to bet his life on, and an elliptical orbit around the sun was likely too close for the shielding, besides which, it would add to the ship’s speed, and any rescue attempt after perihelion would face an even greater initial exit velocity.

  “Would you be willing to take on this mission? This is not a perfunctory request, or the kind where failure to accept would damage your career. I want a committed and interested volunteer. If you’re uncertain, I will understand, and not a word of this meeting will ever appear anywhere.”

  Tavoian didn’t think of hesitating. “I’d very much like to do it, sir. Very much.”

  “Good. I thought you would. You’ll have a formal briefing early tomorrow. We’re aiming for a 0700 departure. You’ll have to hold off informing your astrophysicist friend for several days. After that, it won’t matter.” The colonel’s smile turned wintry. “It might not matter anyway, but there’s always the chance that it might.”

  “There’s not a problem with what I tell her when I can message her?”

  “Not about your undertaking the mission. Some details should remain undisclosed, but you know what those are.”

  The colonel’s matter-of-fact attitude about Tavoian’s messaging froze him for a moment, before he asked, “And messages from her?”

  “You’ll get all incoming messages. Burst sent all at once.”

  “Encrypted, of course.” Tavoian managed a smile.

  “Of course. We wouldn’t want to make it any easier for the Sinese.”

  As he left the colonel’s office, Tavoian had the feeling that making it hard on the Sinese to intercept communications would be the easiest aspect of the mission. He also began to question how such a mission would be even possible with a conventional FusEx or even with the reconfigured Recon burners. The object was somewhere beyond Mars, and Mars was about as far as burners could travel with passengers, under current fuel and habitability considerations. Going months? Even with a crew of one…?

  Yet … for a possible alien artifact … a onetime solar express? How many pilots would have a shot at something like that?

  30

  DONOVAN BASE

  1 NOVEMBER 2114

  Late on Wednesday afternoon, Tavoian received word that his departure time had been shifted to 1100 UTC and that his briefing would begin at 0800 the next morning. That didn’t exactly help his thoughts, especially the more he considered the mission, exciting as it had seemed initially. At 0755 on Thursday, he stepped into the colonel’s inner office. His mouth was dry.

  Unlike most times, the colonel stood. He also wore the dark blue uniform shipsuit of the Space Service. He handed Tavoian a flat package.

  “Sir?”

  “At ease, Major. Those are your new rank patches. There needs to be some reward for what you’re about to do.”

  After that indirect reminder that he was about to undertake a dangerous mission with less than optimum resources, Tavoian thought, only momentarily, about replying in Latin—with the old phrase “morituri te salutant,” but instead said, “Thank you.”

  “I know what you’re thinking. You’re right. It’s dangerous, but no more so that the other mission you’ve been training for … and it might even be less so. Especially for you.”

  Tavoian didn’t miss the double meaning behind the colonel’s words, but just nodded.

&n
bsp; The colonel gestured to the vacant chair and seated himself. “First, some preliminary explanations. The basic problem we have is that almost everything in the solar system is in the wrong position for an easy and quick approach to the target object. The object’s already in-system of Jupiter, even of the asteroid belt, and still well above the ecliptic. Mars is nowhere close to where you could use it as a gravitational fulcrum to kill your outbound velocity and change course. Given the Earth’s position, you’ll get a boost from its orbital velocity after separation. We also can’t get you to rendezvous with the object with enough remaining fuel or habitability, not with a conventional burner. That’s why we had to come up with another approach. We’ve stripped another burner down to the basics, and turned it into the equivalent of a booster. It’s little more than engines, directional thrusters, and fuel. The flight profile is simple enough. The booster will accelerate your Recon bird for two hours at one gee, rest for two hours, accelerate for two hours at one gee, using the same pattern for the first sixteen hours. Then you do an early turnover and coast for a bit less than a week before beginning decel…”

  Early turnover?

  Even before Tavoian could verbalize the thought, the major replied to the unspoken question.

  “That allows you to lead with the booster fusionjet. The way the connector structure is designed, if you do encounter something that you can’t detect fast enough to avoid and too large for the Whipple shields to handle, the entire booster will absorb it. You’re going to be moving about as fast as any piloted craft has ever gone.” The colonel continued without even commenting on the velocity required for the mission, as if it were obvious.

  Tavoian supposed he should have realized the reason for the early turnover.

  “… The booster should last long enough to kill your outbound velocity. Then you’ll separate, unless there’s fuel remaining. You’ll need about an hour of acceleration to match speeds with the object and close on it. The target is calculated to reach an inbound speed of thirty-six kays per second at the time it crosses the orbit of Mars. You will intercept it inside the orbit of Mars at a solar distance of approximately one point two AU on November eighth. You will deploy all cubesats and other recon equipment as expeditiously as possible, and then follow with exploratory AIs, depending on what initial reconnaissance discovers.”

  Tavoian nodded. “How did you manage the booster conversion so quickly?”

  “We didn’t. It was something we’d already tried for other reasons.”

  “Since it was there and no one had another use for it?”

  “There are other uses for it, but nothing as pressing as your mission.”

  “Aren’t the Sinese going to do the same thing? Or the Indians? Even the EC?”

  “It’s a matter of fuel and timing. By sending a single-pilot ship, we get more time on station because of habitability. Even so, for safety’s sake you’ll need to break off near or just inside the orbit of Mercury. For purposes of the mission, we’re calculating that distance at an average of fifty million kays.”

  Tavoian managed not to frown. Mercury’s orbit was the most eccentric of all the true planets in the solar system, ranging from roughly forty-five million kays from the sun to seventy million. Selecting an orbital figure slightly larger than the orbit at perihelion gave a greater impression of a safety margin, while allowing several more days of dealing with the artifact. But it’s only an impression.

  “At that point, you’ll have a closure rate with the sun in excess of fifty kps. With a solar escape velocity of close to seventy kps at that point…”

  Tavoian got the picture. The longer he stayed with the target, the longer the fusionjet would have to fire, and he would need roughly four hours of acceleration to reach escape velocity, except that was an oversimplification because he couldn’t risk more than two hours of continuous acceleration without overstraining the drive. Then, once he canceled the solar closure rate, each hour of acceleration would move him farther away where the escape velocity was lower. Even so, getting close to the sun was pushing it, given that fusionjets weren’t designed for long stretches of continuous use, even at power settings of less than one gee. If he had time, then there were other options, but since sustaining habitability for more than two and a half months would also be a problem, he likely wouldn’t have that much margin in terms of time.

  “Did anyone consider a totally robotic mission?”

  The colonel looked unhappy at the question. “Let us just say that there are issues of both equipment and security involved.”

  Like the fact that it might be far more difficult for the Sinese to deny involvement with an “unfortunate” accident to a manned mission? Or even that requesting certain equipment might scuttle the mission? “I take it any data or information sharing will be handled by Space Command? And to say that if anyone commlinks and asks me to share anything?”

  “Exactly. We’ll immediately release any spectacular visuals … for a number of reasons.”

  But not any that might reveal tech secrets.

  “Also, no comms for forty-eight hours. Except in case of an absolute emergency. After that, standard commlink procedures. As I said earlier, personal comm messages are allowable, but they’ll be checked and relayed.”

  “Yes, sir.”

  “There’s another aspect of this you need to remember. The booster linkage isn’t feasible for an attack or anything but straight-line constant acceleration or deceleration. You can’t make rapid shifts in acceleration or deceleration, or you could break the linkage.”

  And that would abort the mission and maybe worse.

  “You will carry two torps, but they won’t be usable until after you separate the booster. You shouldn’t need them until after separation in any case.”

  Because there won’t be conflict or danger until you near the target, and then, only if it is an alien artifact.

  “We need to go over the basics of your cargo, mainly AI components with a variety of body types and propulsive systems, some with grabbers, saws, that sort of thing.”

  “What about a diamond nanorod drill or a drill or sampler like it? An artifact with that kind of albedo and no marks on its surface might be incredibly difficult to obtain pry samples from.”

  “Silvered silicon…” The colonel paused. “I’ll see what I can do. Just a moment.” Whatever the colonel did was near-instantaneous, most likely through an implant. “Back to the AIs and the associated equipment…”

  Tavoian listened.

  After fifteen minutes, the colonel smiled. “You’ll have a week en route to go over all of this. There are complete schematics in the ship’s database, two sets, one in the AI and one in your personal infobank. There’s also a print manual as backup.”

  After that, Tavoian got a briefing on the mission profile, from the timing, the possible corrections necessary, and if the object turned out to be alien, what Space Command would like, and if it did not, all the astrophysical and other data the scientific types would like. In the event of the second case, the mission would be much shorter, but it was clear that Space Command believed strongly that the object was more than a unique asteroid. It was also clear that time was of the essence, especially in getting a Noram spacecraft to the object, and that the colonel had been ordered to get the most suitable pilot from those available at Donovan Base.

  Carrying his kit, Tavoian reached the lock for Recon three at 1030 UTC, meaning that he had little time to waste. But any delay was the colonel’s, and a few minutes won’t change much for something that’s been there a long time, especially since this isn’t a preprogrammed mission where every second changes every calculation.

  Except every second did change every calculation. It was just that Recon three’s AI could make those adjustments so that a few minutes or seconds didn’t change much, especially since Tavoian wasn’t getting any help from any other planet’s gravity field, beside Earth’s.

  He cycled the locks and lock doors to enter the spacecraft
and, once aboard, made an interior inspection, noting that Recon three had been converted from a standard fusionjet, with a tiny galley in the passenger space and an extensive food supply, extensive for a fusionjet.

  He stowed his kit before making his way to the controls, where he strapped in and activated the control system. “Commence booster checklist.”

  Tavoian went through the booster checklist with the AI, because he wasn’t familiar with it, although it was effectively a second, if shorter, FusEx checklist. Then came the checklist for Recon three.

  When he finished, he commlinked Operations. “OpsCon, Recon three, ready for release.”

  “Recon three, you are cleared for ungrappling and release this time. Cleared for use of thrusters. Notify when you have full separation before ignition.”

  Those weren’t precisely standard release instructions, but clearly Operations did not wish to broadcast that the boosted Recon three needed greater clearance from the docking link and Donovan Base … or that it might be boosted or otherwise different.

  “OpsCon, will notify readiness for ignition.” Tavoian watched and monitored the AI as it eased the overlong booster and ship combination away from Donovan Base.

  “Begin orientation.”

  Tavoian had to wait several minutes before the AI reported, ORIENTATION COMPLETE.

  “OpsCon, Recon three, ready for ignition.”

  “Recon three, you’re cleared for ignition this time.”

  “OpsCon, commencing ignition. Request departure clearance.”

  “Recon three, you are cleared to depart.”

  “Activate drive.”

  DRIVE ACTIVATED.

  The gentle pressure began to build, pushing Tavoian into his couch as it gradually approached a full gee of acceleration. It had to be his imagination, but he felt that the Recon three booster combination was somehow slow and sluggish. Yet a one-gee acceleration was a one-gee acceleration. It just took more power to accelerate more mass. And much more Hel3 …