Chapter 47 Day 93 Engine Shutdown
01
I awoke with a start. To silence. Which wasn't right. I tried to get up and the hammock swung wildly. Free fall. That wasn't right either. I swung my legs down and managed to snag my slippers below the hammock and half flew, half stumbled for the starboard door-panel of my sleeping cabin. It opened directly onto the companionway, and grabbing the companionway's railing, I swung myself around the short stretch to the bridge.
'What's wrong?' I asked Molaye and Illy, Molaye perched over the engine room console.
'Emergency engine shutdown,' said Illy.
I touched my com link and called Lilm. 'What's up Chief?
'Hot spot shutdown for the main engine, Skipper,' Lilm answered laconically, adding. 'Not a false reading.'
'A breach?'
'Don't think so. Minor if any. Ten's having a look and Riv's just flown by.'
'I'll be down.'
'Standard un-powered procedures,' I said to the watch and swung out. Illy, at least, knew what had happened. I'd no need to say more.
I stopped at my quarters to pull on old trousers and a rugged jersey and headed for the main well where I met Myes flying down the shaft. 'Hot spot?' he asked as I joined him.
'Main engine,' I said as we dived down the well. 'No breach, apparently.'
We shot past the engineering deck to the platform in the engine room. Myes swung off the platform and continued hand over hand down the steep ladders into the depths. I hurried over to the control platform to join Lilm who was leaning over the railing staring down along the length of the main rocket engine.
'What happened?'
She shrugged without looking up. 'Just a warning and an automatic shutdown. Don't know more than that. You'll have to ask the boys down there.'
'You don't mind if I go down to take a look?' As I've mentioned, the engineering staff does not encourage tourism in their department. It's best to ask their permission just to keep on their right side.
'Go ahead. I'm sure they're just standing around looking serious. Too hot to do anything for a couple of hours.'
'Thanks,' I said, and headed for one of the spidery stairs running along the engine frame for the light thirty yards below. I saw Min arrive from the main access well and paused to wait on her arrival. I gave her the word as we dove downward, pulling ourselves along using the ladder railings leading to the depths of the engine room.
The gang was hidden behind the bulge of the combustion chamber. I found Ten, Myes and Riv right at the bottom of the engine casing where it met the stern bulwark standing about in several directions as Lilm had predicted, looking at a very discolored, semi-melted spot in the support patterns of the engine casing, perhaps 30 centimeters in diameter. Min and I joined them. Nobody said anything, so I decided I might as well ask.
'What are we looking at here, besides that dark spot in the casing,' I added in an effort to forestall any sarcastic replies.
'That's it, Skipper. A hot spot. A breach of the inner liner. The hole allowed a jet of hyper-hot plasma to leak and start melting the outer, D-Steel casing. More than that I can't say until the engine cools enough to send a service bot out to have a look at the rocket liner.'
'Can't be wear. We've decades of service left in this unit, right?'
'Should have. Seeing that it's only two meters into the nozzle, I'd say it's likely impact damage from some meteor that must have hit it when the engine was cold and pitted it badly enough that the plasma has now breached the inner liner,' said Riv, and squatting down and pointing, added, 'If that's all it is, we can deal with it in two watches, but here's what we're looking at – see how the discolored scar looks asymmetrical... And if you look closely, you can see some discoloring flaring out on either side? Here and here. And it's hot too,' he added as he traced a long line from the hot spot with his hand just above the surface. 'I won't know for certain until I can get a service bot into the bell to have a look, but I'm thinking the liner's fractured rather than just holed.'
'Damn,' I said.
'Damn, it is, Skipper, and just by the look and the heat, it's a major one. At least two meters long, maybe more,' Riv said, adding, 'A pin hole would be no problem. We'll just drill through the two layers of casing and plug it with a rivet patch we've on hand. This close to the end, it'll last for years. I've served on ships with engines so old and eroded that hot spots had to be plugged just about every time they were fired up. Had several when we brought the Lost Star across to Azminn half a century ago. Credits seemed a bit thin in the nebula in those days. But a fracture's a star of a different color. I've never had to deal with one myself, but fractures are very likely to spread and get nasty very fast. It's a good thing this was caught in time; we could've lost the stern of the ship if it had breached the outer casing.'
Damn, indeed. I stared at the discolored spot in the D-Steel casing along with the rest of them and glanced around at the grim faces staring at the spot silently. This was not good, not good at all.
I'll not go into too much detail, but briefly, a rocket engine is largely build with D-matter alloys designed and built from the subatomic level up to create characteristics not found in naturally occurring elements. D-matter materials are a result of the ancient discovery that elementary particles were not pieces of matter but something analogous to small bits of code, a description of a function rather than an object. In the centuries that followed, a method of re-programing this cosmic code was developed. It involves vast amounts of energy and rare elements and extremely high temperatures, but D-matter materials are now produced routinely, though because of the energy involved, on remote moons and in the drifts for safety. The same process could be used for naturally occurring matter, but mining those elements is a lot less expensive with the almost unlimited supply that exists in the drifts.
The inner liner of a rocket engine is a 3 cm thick layer of one of these D-matter materials called D-matter radshield, or simply D-Rad. It's engineered to be impervious to the full spectrum of radiation from thermal to cosmic. It lines the rocket's combustion chamber preventing both the radiation and intense heat of the plasma drive from escaping. The same D-Rad alloy is also used to shield all the ship's atomic reactors and as a layer of the ship's hull as well. It is not, however, structurally strong enough to contain the pressures within the combustion chambers of the engine and so there's an outer casing made of D-matter steel, or D-Steel a super strong steel that is used in the outer casing to contain the intense pressure of combustion. A third D-matter alloy is used in the rocket engine – D-matter Therm or D-Therm – which is an alloy that absorbs and withstands temperatures several magnitudes beyond that which would turn ordinary matter into plasma and it is used to radiate the intense heat generated by atomic fission to achieve a nearly complete conversion of our hydrogen fuel into propulsion.
A small hole, and likely a crack, in the inner, D-rad liner appears to be allowing the intense hot plasma of combustion to reach and begin melting through the outer D-Steel casing. This is a known hazard and the outer casing is monitored with heat sensors, that would automatically shut the engine down before the plasma jet burns all the way through – with luck. If the liner did have more than a pin hole, if it was indeed a crack, the plasma would likely work its way along the crack, vaporizing the underlying D-Steel casing, rapidly extending the crack, creating a large fissure in the outer casing allowing a powerful jet of plasma to be released into the engine room under intense pressure, wreaking havoc on equipment and people, potentially destroying the ship as well as it vaporized everything it touched.
A pin hole can be mended aboard the ship by drilling out a small hole and securing a broad rivet-like D-Rad headed patch over the hole, but in the case of a fracture, it is rarely possible to get a large enough patch to securely cover the whole of the fracture to keep it from spreading. The standard remedy for a fracture is to cover the affected part of the engine with a large D-Rad ring – a second lining as it were – that allows a v
ery generous margin of coverage to make sure that the plasma under great pressure and super-heat would not reach the fracture area under the patch. In this case, the entire bell of the engine would likely have to be have a second layer of D-Rad installed. It would be a fairly expensive repair, and we'd need a shipyard to do it.
'Damn,' I sighed yet again. I turned to Min, but she only shrugged. 'Nothing more to be learned staring at this. Send up your report once your bot has had a look. We'll need to know our options.'
'Right,' said Riv, with a nod to Min and me. 'If it's a fracture, there won't be many options. It's a shipyard for certain.'
'Then let's hope it's just a pin hole after all.'
'If wishing works, it will be. But I'd not hold my breath.'
Min and I turned away and hauled ourselves slowly up through the maze of platforms along the lines of steep stairways in silence. The good thing was that we were in no immediate danger.
'You're quiet. What are you thinking?' asked a somber Min as we reached the control platform.
'I'm trying to do the math in my head. I'm thinking we should have time to decelerate using the balancing engines and not end up deep in the Myzar Drift.'
Having just cleared the Anjur passage we had been using our main rocket to shape our course for Zilantre. We had another 24 hours of main engine burn left to make that course change. Then we would've coasted for 36 days before firing up the main rockets to begin our deceleration to match speeds with Zilantre.
'The balancing engines flat out can provide about 30% of the power of the main engine, so we'll need at least 70 additional days to decelerate and that'll extend our passage to at least 90 days from this point, putting us a bit over two weeks beyond our delivery deadline,' she replied. 'I think we can assume it's a fracture and that we're not only going to be paying the late delivery penalties, but the expense of relining the engine as well.'
I glanced aside. She was calm, but grim. I don't know her credit balance, nor did I know what a liner patch would cost...
'Our insurance will not cover the cost of repairing the liner – it's considered a consumable item, but we should be able to claim the delivery penalties, since I don't see how a meteor fracture could be considered negligence. It will, I suppose, take time to see those credits though. Still, I'd think that Zilantre as a gateway world to the deep drifts would have shipyards capable of repairing the liner. I'd imagine this type of damage happens fairly frequently in the drifts,' I said, as cheerfully as I could manage.
Reaching the bridge, I briefly relayed what had happened to the crew on watch, and Min and I retired to my office.
'Any idea what the repairs will run?' she asked.
I shook my head. 'I was a mere pilot during our last major refit and was on a long leave as well. I'll look in our logs and Guild estimate tables, but in the drifts, who knows what the going price is? We should be able to get by just re-plating the bell section, since it's a very common N33 standard engine.'
'Oh, I'm sure it can be fixed. But at what price? Delivering the boats late will put a big dent in our profits, so it's likely at least part of the repairs will have to come out of my contingency fund... which is not bottomless,' she added grimly.
'Still we've insurance to cover the delivery penalty, and two quarter boxes of trade goods that should bring in at least fifty thousand credits. We might have to dip into the contingency fund while we wait for the insurance credits, but I'm certain we'll get by.'
'Oh, we'll get by... this time. I just hate the thought of losing all those credits.'
'I don't see how that can be avoided. Still, it could have been a lot worse – we might have been in the long boat with a long voyage ahead of us or dead... As it stands now, it is not a matter of life or death, just credits.'
'My credits,' she said grimly.
'Your credits,' I agreed.
02
'A fracture,' Lilm said, as she, Myes and Tenry filed into my office (Riv had the watch), 'Runs close to three meters long.'
No surprise. 'I suppose we'd best see Min,' I sighed. I pinged her to see where she was, and then pinged Vynnia to join us as well. I rose to my feet. 'What do we need to do. Chief?'
'Get to a shipyard and reline the bell,' she replied tartly as we stepped out into the passageway and headed for the main access well to take us up to the owner's suite. 'Though Myes has a drifteer option.'
I looked to Myes, 'A better option?'
'A drifteer option. Let's just say another option. An old drifteer trick,' he replied.
'And what, would that... Oh, let's wait until we have Min in on this. This isn't going to be my decision anyway.'
Min and Vynnia were waiting for us in the companionway outside of Min's quarters, and after we'd filed into the small office and found a place to sit or perch, I asked Lilm to give her report.
'...so with the fracture running around the bell, and no more than three meters in, we might be able to get by relining only half of the bell. If we were in the planetary trade, with a day or two burns at a time, I'd say we could go with that. But with these long burns, well, it's an iffier call. A full bell reline would be my recommendation,' she concluded, adding, 'However Myes has suggested another approach. I've heard stories of it being done, but have no experience with it myself.'
'Myes?' asked Min, turning to him.
'Well, Tally,' said Myes, shuffling in his seat a little. 'I grew up and worked in the shipyards of Larvella in the Alantium Drift,' he began. 'They're little drift shipyards which devote most of their time salvaging and keeping wrecks of ships semi-space worthy. The deep drifts are pretty poor so even the most decrepit ships are kept operational until they no longer can hold air, and only then are they broken up for parts.
'One of the techniques we used to extend the life of a rocket engine with holes or fractured nozzle chambers – pretty common in the deep drifts – was to remount the engine so that the damaged part of the nozzle bell extended from the ship. Then we'd trim the nozzle to eliminate the fractured section. The profile of the bell, after having been cut down is, of course, less than optimal, but with the danger of fracturing removed, the engine could be reliably operated as usual.
'Now I must say that all the ships I've seen this done to were much smaller than the Lost Star. Small, drift traders mostly, but I'm thinking that in principle, it should work for a ship our size too. We're only looking at moving the engine some 4 meters down and trimming off the last 4 meters of the nozzle bell...'
'But can we do that in space? we don't have a shipyard handy,' I asked.
'Well, that's the question. We'd have to look into what it'd take to do it and make it work. Still, we have more than a month to detach the engine – reactors and all – from the mounting frame, move it down and reattach it. I don't think that would be a problem in free fall. Of course, that's just the beginning. We'd have to extend and jury-rig the fuel lines and controls again, and cut the nozzle down – service bots can do that while the other alterations are going on. And in the end, we'd have a rocket engine that would be perhaps 10% to 15% less efficient but could go on operating more or less as usual likely for years, if necessary. And there's no reason why we couldn't save the section we trim off, and when we wanted to re-plate the bell, bolt it back on and move the engine forward again when the credits are available.'
'So what you're saying Myes, is that we could – if we're willing to accept a less powerful engine – fix the problem in transit and in time to use the engines to decelerate on schedule and make our delivery deadlines,' asked Min, leaning forward over her desk.
'In theory. We'd have to chart the whole process out to see what would need doing, if we could do it, and how long it'd take before I'd say yes. Even if possible, it might be too iffy to try it in transit. We could just wait until we're in Zilantre orbit, where we'd have the resources of a shipyard to call on if needed.'
I glanced at Lilm and Tenry. 'What do you two have to say about this idea?'
'Oh, it wor
ks,' said Tenry, 'I've seen it done in smaller craft anyway, and it should, in theory, work on a ship of any size as well. But I can't say I've ever heard of it being done on a ship like ours. Ships our size are worth the expense of re-plating. And you're crippling the ship's engine and will have a higher fuel bill because of it. So it has some serious downsides.'
'So at this point you're not all in on this idea,' I asked. The engineers would stick together once they settled things amongst themselves, but they hadn't yet, so I wanted to get each individual's opinion now, if I could.
Tenry shrugged, 'Do we need to be?'
'I'm not entirely sold on the idea either, Skipper,' admitted Lilm. 'In part because we haven't had the time to look into it. I'm sure there's a hundred big and little things involved in moving the whole engine and reactors that we haven't had time to consider yet. And I'm not sure we've the resources. Myes is talking about a shipyard operation.'
'By resources do you mean things like tools, extra piping, wiring and such, or hands to do the job?'
'All that. I'd have to examine the ship's support structure to make certain that can even be done, and there’s all the fuel pipes and controls that would need to be extended, fuel line supports and the injector module remounted... and, well, the list goes on,' replied Lilm. 'We can manufacture the extra piping, and jury-rig the mountings and such, nothing beyond our expertise, but we'd have to have everything working within 35 days with no margin of error. Run into something unexpected, and well, we'll be in the drifts beyond Zilantre before we've killed our velocity. We're going to have to look very closely at everything involved in the operation before we can give you a definite answer.'
'Ten?'
'As I said, I've seen some pretty jury-rigged engine rooms in my time, so I'm certain it's possible, Skipper. But on a ship this size... well it's not the way we did things in the Patrol.'
I turned to Vynnia. 'Anything to add Vyn?'
'Speaking without knowledge of Tally's credit balance, I'd say that since we can make it to Zilantre on our balancing rockets, late, but reliably so, we might want to consider long and hard about making such a semi-permanent adjustment to the ship. In orbit we can price out our options and if this still seems viable, we can go for it.'
Thank you, Vyn, I said to myself. That was pretty much my opinion too, but she saved me from having to say it.
'Can it be done while under power? If you work while we're decelerating using balancing engines, we'd not be taking the big chance, save the trimming down of the nozzle to the last when we're certain it'll work, and depending on when we start and how aggressive we are about decelerating with the balancing rockets, we might be able to make our schedule...'
'That would make the work harder just because we'd be looking after the balancing engines at the same time' said Lilm. 'Plus, we'd have to set up and work from a lot of scaffolding which would make the work more time consuming. Perhaps in the final stages it wouldn't matter as much.'
I glanced at Min and gave her a Your call look.
She swatted it back with a look and a shrug. 'What do you think, Wil?
'I'm thinking along the same lines as Vyn, on this one.' I had rather hoped to avoid sounding like cautious old Captain Crofter, but well, I had to be honest too, though I did add, 'I'm willing to be convinced, but it'll take a solid, unanimously agreed on plan from our engineers.'
'Right. Still it sounds like it's worth looking into,' said Min. 'But we'll need to see a detailed outline of every step you'd have to take and how long it would take you to accomplish each step. We need to be certain of success since we'll be digging ourselves a hole in the deep drifts if we hold off decelerating only to find out it won't work. Take the time over the next few days to go over every little detail. We'll resume our course change using the balancing rockets and that'll now take us the better part of four days, and we won't need to start decelerating with them if we go that route for a few days after that – so you have time to go over the whole idea very carefully.'
After the engineers had left, Min, Vynnia and I sat about talking over our various options. Owners and captains have slightly different priorities. My first priority was getting the ship to orbit safely. Repair costs were not my direct providence and I didn't know Min's credit balance. Our trade goods should provide immediate credits if needed, and the insurance down the line would cover our loss for missing the delivery date, so I didn't view the situation as a dire crisis requiring desperate measures. I was happy to see that Vynnia was taking the same, safest, course I'd prefer, but except for voicing my support of Vynnia's caution, I kept my personal opinion to myself as much as possible. Vynnia, I was certain, could get away with being a lot more direct than I, so I'd let her push the sure and safer course, especially since I knew enough about Min to suspect that she's wouldn't shy away from taking a chance to deliver the boats on schedule despite our misfortune. It would be a coup, and could establish a very useful reputation for the Lost Star.
I suppose, in the end, my luck had to run out sometime. We'd been pretty lucky, and were lucky even now. We could be in the small boats with several months of travel ahead of us. Or we could be dead. We'll see what the engineers come up with.