11 December 2009

Inbound: Going Bump In The Night

Lupine, a ten-mile-long city in flight Blish never dreamed of, was coasting in zero-g. This is no fun but we'd bounced in a little off-kilter and Navs had so decreed. If you're not susceptible to falling dreams, it's not so bad for sleeping; tuck in the covers and drift off like Little Nemo! I woke up about three-quarters when the alarm sounded and my cabin lights blinked on and then off again. From the phone panel set in the wall next to my bunk: "Final warning! Acceleration in thirty seconds! Take hold!"

It sounded like Navs finally had us lined up for our first inbound course correction.. About time; I was already tired of squeeze-bulb instant coffee. I hoped it was going to be a long burn.

I was still recovering from my brush with death at the hands of a unbalanced Edger -- or a fanatical member of their Home Guard, take your pick; either way, Irene nearly got me. I'd been sleeping a lot and ordering in meals; it's not cheap but even though Dr. Poole himself had cleared me to go back to work (and the Chief was fuming at his restricting me to light duty, or at least faking it convincingly), I was not a hundred percent.

So I just laid there muzzy headed for a few minutes before blinking my eyes into some semblance of focus and palming the lights back on -- there's a handy switch for that, right below the telephone panel -- then took a quick look around. Nothing unsecured but my jeans and they weren't going to hurt anything. It's not like a NASA-front moon shot from the '60s; Lupine ramps up thrust over a period of several hours to get back to our normal three-quarters g, plenty enough to make down stay down. With that happy thought, I drifted back into a big, fluffy gray cloud of sleep.

BA-BUMP! A big double jolt woke me right at the threshold of sleep. I kept my eyes shut, thinking, hoping, probably just a reflexive kick, and drifted back off.

Bzzt. Bzzt. Bzzt. BZZT! BZZT! "BOBBI!" It was later but I had no idea how much. Lights were still on, my pager was bleeping and the telephone was saying my name. I slapped at the big PHONE button, said something and got a worried-sounding reply. "Bobbi? You awake?" It was Kent.

"Mororless... Wha...?"

"I said, are you up?"

"YES. Whaddizzit?"

"I dunno, the 'Drive just dropped off and we can't restart it. Drive Control keeps getting SWR trips. Doc Schmid was here and he said to call you -- he's already headed for the 'Drive compartment."

Lupine's Second Officer is a first-rate Navs boffin and fully-qualified for 'Drive work but it's been a very long time since he slung solder or swung a wrench. Suddenly I was a lot more awake. And it hit me what the double bump had been: 'Drive quits while we're under heavy thrust; we stop bein' so slippery in realspace and the reaction drives throttle up to compensate, almost immediately. "Almost" is what makes it bumpy. The big MHDs downstream of the fusion reactors (all of it tended by the Power Room gang) have significant control lag -- jokingly known as "turbo lag" -- so all the RF-pumped ion maneuvering drives already running on our normal "down" axis were briefly pushed to 120% and then backed off in a not-quite compliment to the MHD starting to roar. All perfectly normal behavior, not that you ever get used to it. I sat up, peeked around the corner to see if I'd left the phone camera off (yes), got up and started digging out clothes. "Tell him I'm on my way." So much for that nice warm bunk and a full night's sleep. "Have you made sure Navs is aware?"

Kemp averred that A) he had; B) the navigators were swearing and C) they wanted our best guess when we'd have the 'Drive online again ASAP. No doubt -- with the 'Drive pulsing away on low, we can cheat at physics; lose it and they're unexpectedly playing at Newton's table. Oh, there'll be one or two what-ifs covering this kind of failure running already, there's a reason most starship navs types are avid chess and Go players, but they've got to get it updated in a hurry and start working up what-ifs based on how soon we get the 'Drive running.

Nice damn timing. An SWR fault, especially at the low power level used for sub-light maneuvering, is about sure to be between the big final amplifiers we were headed in to replace and the CLASSIFIED, or possibly between it and the 'Drive field radiator. Easily-found external evidence of exactly where it might be is unlikely.

One item in our favor I didn't find out about until I got to the 'Drive compartment was we had some extra and very high-zoot test gear; while I slept, Dr. Schmid had received a Mad Rushin' delivery of an elderly but nice Network Analyzer, on loan from the Company HQ, Earthside -- Earthsideish, that is: Farside City on the backside of the Moon. He had decided it couldn't hurt to have a look at the CLASSIFIED and the new combining system using our own gear and ansibled the request right before we dropped back into normal space.

A quick aside for readers not out here on the Hidden Frontier: "Mad Rushin'" or "Mad Russian" is a nickname; the outfit calls itself "Express Delivery Service," only in Russian, and they fly small, egg-shaped FTL vehicles that consist of a hot (in more than one sense) power plant and oversized Stardrive, a smallish cargo bay, a screamin' basic Navs setup and one (1) young, well-trained, enthusiastic and optimistic Russian star-flyer in a ruggedized space suit; there's no other enclosed life-support. Most of the "drivers" were born on the old Red planets, nearly all are former Soviet Space Arm (the real one) and every last one of them is a born gambler. The death toll isn't quite as bad as you might think but nobody's offering them life insurance policies -- and when it absolutely, positively has to be there in four days or less and price isn't a concern, your best (and most often only) option is a Mad Russian, popping in and out of a high-order 'Drive field and taking exactly as many Rads as his employer's medical advisers permit. A difficult-to-read font I assume is Cryllic says "BisPosEtKom"[1] on the olive-and-crimson labels, but in English just about everybody calls it some version of "Mad Rush Shipping," including them. Story is that most of their courier ships have been retrofitted to modern fusion reactors now but nobody's willing to sneak aboard to check and most of the hulls still have "hot" spots, so you can't be sure from a distance. So, now you're up to speed -- and so was I, on a mad rush of my own.

It's a good ways to the closest connection between the crew-level slidewalk system and the ship's only direct maintenance-vehicle connection between the control center and the 'Drive compartment. This is all to the good, as there's no slidewalk in it, just narrow, railed walks along the sides. I jog-trotted that stretch, grabbed wildly at the rail when the deck swayed once, kept moving and was out of breath when I came through the hatch to find Dr. Schmid, Big Tom and four suited-up riggers looking every bit as happy as you might expect guys who'd normally be hitting the bars and/or the arcade about now. Tom looked sheepish and the conversation shortly revealed why.

Dr. Schmid said, "Oh, hi, Bobbi," and as I dogged the hatch,he added, "The Chief'll be here any minute with the adapters and cables."

I looked at him and raised an eyebrow.

Tom spoke up, "Um, I was told was to bring the analyzer; I didn't see anything that looked related near it."

Dr. Schmid managed to look tired and noncommittal at the same time. "Power's up as high as we can make without VSWR shut-down."

I glanced at the control rack display for the 'Drive finals: idling at about two percent peak power, with a duty cycle that should knock our effective mass down to about 85 percent, and asked if the riggers had 'laid hands' on the big coax yet. The crew boss, Dan, shifted uneasily and said, "Nope; we'll have to rig and I figured you guys would want to make with the Big Science first."

"Can you send two guys out with an IR camera, scope the line, and then get started with as much as can be done without shutting down the Stardrive?"

He nodded and glanced at Dr. Schmid, who nodded back and said, "Might as well. We'll watch on the monitor in here, get as many eyes on it as we can. At ten percent..."

"Yeah, we might not see much." The boss rigger turned to his crew. "Randy, Jer, gear up and head on out."

* * *

Sure enough, we didn't see much; maybe a warm spot seventy meters out but zooming in didn't resolve it any better. The riggers packed up the IR camera and began, well, rigging, setting up the lines and winch they'd need if we'd lost a section of transmission line. In the accessway along the CLASSIFIED, Big Tom and I unstowed two spare concentric-line sections (19.35 feet long, 6.125" OD and much too heavy even at Lupine's normal three-quarter g; there's a lot of copper in them) and laid them ready on the deck.

As we ambled back into the 'Drive compartment proper, the Chief arrived carrying a mailbin loaded with books (hey, Starship Company, ever heard of CD-ROMS? Thumb drives?), bright blue precision cables and two big boxes of adapters and calibration ends (shorted, open and cal-lab-accurate 50 Ohms) for the network analyzer, each marked KEEP WITH NET. AN. AT ALL TIMES!!! "Found it under a 50-foot coil of 12/3 cable, the whole thing bungee-netted to the deck," he puffed.

Big Tom looked relieved at this news. I took the bin from the Chief, hauled it around behind the Stardrive final amplifers to the analyzer, sat it down and dug out a book, right volume on my first try; it'd been at least a decade since I'd messed with one of these and the trick we needed to do -- swept bandpass time domain reflectometry, "radar on a rope" -- is not the most obvious mode to set up. If all you remember about a thing is that it was difficult and counterintuitive, it can be a powerful incentive to relearn fast. All the more when your boss and his boss have both walked back to look interestedly over your shoulder.

Chapter 2, INSTRUMENT MODES, page 2-12, TIME DOMAIN, just a brief description of Option 010. Chap.6, MEASUREMENT, page 6-29, pay dirt! Bandpass TDR, yes, yes.... I punched buttons and got into Transform mode, nifty, set Start and Stop and hey-dammit! Can't get the thing pushed out past a couple hundred nanoseconds, not ten pecent of the time (distance) we'd need. I looked around in frustration to see the Chief take his celphone from his ear and make a throat-cutting motion, turned to see Big Tom walk back to the front of the 'Drive finals and heard the big contactors thud open as the Lupine jolted with the ion drives throttling up in transition. The 'Drive was off; Dr. Schmid cranked the manual coax switch knob around, disconnecting the CLASSIFIED and connecting the line to the 'Drive radiator array with the test port; he hooked one of the precision cables to it and leaned over to connect the far end to the Network Analyzer.

I tried setting the Stop limit to the right value: nothing doing. Knew I was overlooking something but there's nothing in the book... Sweep menu? Start freq, stop freq, right across the critical (and, you bet your life, classified!) band, okay. Now, linear or log sweep? H'mm, it's in linear; I toggled it and went back to the the Transform menu and Lo! A shining victory for semi-panicked fobbing-at-controls! I punched the STIMULUS: STOP button, spun the manual-setting knob and walked the end of the displayed 'scope trace out the line... At 95 meters, a small spike, fine; then at 165, pow! Right off the scale! "Got it, Doc!"

"Don't be hasty," he warned me, "You're not even halfway out."

But there were no other big blips, right out to the gentle trailing-off of the 'Drive array. One-sixty-five was our culprit. Dr. Schmid used his phone to dial into suit radio comms and have the riggers give the line a good whack at the proper point (82 and half meters, since the analyzer gives you the there and back distance). I took out my calculator and came up with the flange between line sections 10 and 11 as the most likely and sure enough, slapping that flange made the spike on the Analyzer's TDR trace dance.

It was enough to even convince Dr. Schmid; he smiled and agreed we needed to replace both sections, while cautioning me to be prepared to find even more damage, "...once the big discontinuity is remedied." He's right far more often than not.

Dr. Schmid took the Chief off to one side and started a whispered conversation. I didn't really intend to overhear but caught, "...found it now...might as well go get what sleep you can. You look like hell and you were awake two days straight when we almost lost--" He noticed me not-really-listening, shot me a look that was almost a glare and I decided to see if there was something useful I could do farther away.

Finding the problem is half the repair; with the 'Drive offline, Lupine was still burning through reaction mass at a wasteful rate. The long accessway for the CLASSIFIED ends at the regular airlock the first pair of riggers had used. The hatch between the accessway and the 'Drive compartment is a full airlock hatch, not just pressure-rated, with a second set of indicators and controls for exactly this job, hauling sections of high-power concentric-line out into the Great Beyond. It's an annoyingly large enclosed volume and takes awhile to pump down. As soon as we'd decided to replace the two suspicious sections, boss rigger Dan and his helper Adrian ("He's a new guy -- transferred up from window-washer in the greenhouse." Or maybe he has a Ph.D. Riggers, I never know if they're serious) had sealed up their suits, shut the hatch and started it cycling. You can't scavenge all the air with a practical pump but you can save a lot of it; unfortunately, the amount lost is proportional to the enclosed volume. So we don't use the big lock unless we must; Lupine is huge but this is a negative-sum game.

Dr. Schmid and I passed the time running the network analyzer and showing Big Tom how to use it. I'd called up the suit radio channel on the 'Drive compartment phone and in speaker mode, we listened to Dan and his crew discussing the job, with occasional comments from the safety officer on duty in the Control Room. Eventually, we felt more than heard the outer hatch open; by then, the first two riggers had unbolted the line sections, jacked the line apart and removed them, and were ready for the two new pieces.

The rest is "mere mechanics," as they who don't have to do it say. The riggers dropped the new sections in, bolted them up and we repressurized the line with dry air to 3 psi above ship standard.[2] Meanwhile the riggers gathered at the hatch, killing time. Takes about fifteen minutes to air the line back up and another fifteen to be sure we don't have any really egregious leaks; there's no point cycling them back in 'til we're sure their work has succeeded.

The first part of pressure-testing doesn't take much attention. Much more interesting was the network analyzer display, now minus the big mismatch blips. There were a few tiny wiggles on the display but nothing's perfect. Ten minutes after shutting off the air supply, the gauge hadn't budged a tick down from just-over-three. Doc Schmid cocked an eye at me and said, "Let's apply some power!" He reached up and started cranking the transfer switch back from TEST to NORMAL.

I went over to the phone, picked up the handset, "Dan? You have have your field-strength meters handy? We're going to bring the 'Drive up slowly; if they get even close to yellow, sing out!" 'Drive energy is nothing to get casual about. "Yellow" on the little meters riggers are supposed to carry is well below the danger level: better safe than cooked.

Punched up another line, the hotline to Drive Control. Eric answered. Good; he's nearly unflappable. "Eric? We're gonna try running the 'Drive up to about ten or twelve percent; set it at 20% duty cycle. Match me with the ion drives, okay?"

"Are you callin' Power Room, or should I? They're kind of unhappy since the big glitch."

"I'll leave that to your tact and diplomacy. Five minutes -- you'll see the rig fire up on the remotes. I'll start at zero and bring it up slowly."

He laughed and hung up. Doc Schmid gave me a nod. "Five minutes. You do it."

Fine by me -- brass he may be but he's got entirely too much faith in the goodwill of the universe to suit me.

Our 2/O has an endless supply of anecdotes, a good many for the days when men were men and 'Drive techs occasionally got knocked into the middle of next week, not always metaphorically. This one involved the old City of Louisville, a water-cooled Klystron-like 'Drive final and contaminated cooling water. I really hope it's not true, but it does begin to explain how the Lousy got its other nickname. After five minutes of that, I double-checked the Christmas Tree displays on the front of each 'Drive power amp, green side lit to READY and red all off, and pushed the BEAM ON button. The compartment lights flickered as the high voltage supplies step-started; the 'Drive came up at zero power, standing current only, and then one of the three finals crowbarred to OFF.

I said a Very Bad Word (as is my habit when these noisy little bobbles occur), checked to see that output was indeed zero, cleared the fault and put that final amp back to STANDBY. Quick as it was, the timers were still happy and the READY led lit up in a few seconds. Gave Dr. Schmid a glance, he nodded and I pushed the BEAM button again. The reluctant amplifier came up, stayed on and I started to breathe again.

Time to see what happens next; I tapped on the RAISE POWER button and watched the Forward Power meters for all three finals and the combined output lurch up a tick. One percent, two, three.... The floor briefly felt a bit greasy underfoot, then steadied. Eric was tracking the (apparent) change in real-world mass very closely. He's good at it. Ran power up a little more, inching up to ten percent. Not a wriggle on the Reflected Power meter. This is what we can safely call A Good Sign. I stepped on up to twelve percent and it stayed steady.

A quick word about power: the meters on the 'Drive finals (and the remotes at DQ) are reading peak power; average power is what fiddles with our relationship to the rest of universe. The average power depends on the waveform, which in normal space is just a pulse, with varying on/off times depending on just how skittery Navs wants the ship to be. It gets way worse making a hole in reality and wrapping the ship up in it but Highly Classified Complexity aside, it's still average power that does the work.[3] So who cares about peak power? Engineering does; it's on the peaks that insulators break down, phantasmajector tubes find fun new ways to fail, and so on and so forth. Like the time we proved (by unwanted example) that Tweed's baseplates for the high voltage safety switches tended to absorb moisture from the air, though we had some help from defective E&PP climate-control with that one; but that's another story. Keep notes -- you might fall on hard times and have to work as a 'Drive tech some day!

Meanwhile, Dr. Schmid was already on the horn with the riggers, asking for another IR scan and redundantly cautioning them to mind their field-strength meters. He hung up and turned to me, "Have Eric hand off thrust to the MHD and we'll run 'er up some more. Might as well find out now if it's going to fail." He was grinning. Unusually for the breed, he loves this kind of dice roll. Me, not so much.

Still, he's right. I'd rather find out inbound to a planet than heading for a Jump or part-way through, especially when our destination has repair facilities. Another call to Eric and some discussion of ion thrust hand-off to Power/MHD, 'Drive duty-cycles and peak power later, Drive Control had walked us down to 1% on-time and I was gradually increasing power again. Without the complex modulation that wraps the ship up in a pocket universe and squirts it along at a rate that has outpaced light when we pop back into normal space at the end of a Jump, it's highly predictable but the shorter the duty cycle, the worse the effects if there's any stutter or irregularity. It nearly always goes okay; but even 10,000-sided dice with one bad side still do have that bad side.

On the other hand, every Jump is a dice roll, too, with a lot more at stake than the jars and bumps of abruptly varying thrust. Lupine is huge but resilient; built for battle, her structure bends under stress instead of breaking. I wasn't especially worried but I kept a hand on a grab bar and my toes under the footrail[4] as I ran the output past 70 percent peak power. The rig stayed steady as can be. Not a tick on the Reflected Power meter.

The boss rigger called in to admit their field strength meters were now indeed at the lower edge of yellow, so we held at 70 for ten minutes, fifteen, twenty.... Dr. Schmid pronounced himself satisfied. He had me run the 'Drive back down to ten percent and hand off full control to Eric in DQ, adding, "Have him call up Navs for their latest runcharts and load them in the automation; I have no doubt we'll soon be hearing from Port Control."

As it turned out, he was right.

The riggers were already cycling the lock, having carried the bad line sections in with them. The bad line would have to go off to one of the machine shops for repair. We were back in the starship business once again.

1. "Bistro Postev'tee Etu Kompaniya," something like, "Deliver This NOW Co." Alternatively and with typically-mordant humor, if you catch one of their brave (or shal'noi, loony; most likely both) pilots when he's well-rested, he'll tell you it means "Now deliver (save) this company," profit margins being very slim when your business model is based on what amounts to a nuke-powered top fuel dragster with a cargo bed. Increasing Internet connectivity is helping a lot, since their dispatching and routing problems are, literally, cosmic. It has paid off for them in other ways, too: every Mad Rushin' vehicle carries an ansible, an e-mail node, ginromous RAID arrays and several different versions of normal-space wireless data transceivers. They've got contracts with many planetary ISPs to carry the e-mail but their own traffic comes first.

2. For the nuts'n'bolts types, what we're breathin' is an oxygen/nitrogen mix at less-than-Denver pressure and with a bit more oxygen than they serve in Colorado. We could air up the concentric line with anything nonreactive, as all we're really after is to keep the inner-conductor connectors from vacuum-welding, prolong the life of the PTFE parts and give hot spots a little extra cooling help. In the old days, they used high-pressure tanks of nitrogen, hauled up and aft from E&PP's chemical plant (greenhouse fertilizer, gunk for air, water and sewage processing and on and on), but a pair of nifty little commercial gizmos do the job now with a lot less heavy lifting and a way lower chance of inadvertent cold-gas torpedoes.

3. Well, really it's RMS power, but you either knew that already or don't care. If you ever need the info, you'll learn it.

4. After every stretch of zero-g time, in addition to the usual bumps, bruises and et learning the hard way that mass remains even when weight is imperceptible cetera, the ship's clinics receive a steady stream of patients with sore feet, skinned toes and suchlike; bracing your feet under the toerails when they don't stick to the deck by themselves gets to be a habit but humans're not really built for it.