Merchant Drop Tanks

[whartung]

Actually, I did include salaries and maintenance -- they're both a big chunk of the overall expense.

But I like the "Boosting empties" part of the system, it just takes a while to "prime the pump" and fill the line.

One of the key considerations was simply getting the fuel from the gas giant to the demarcation point in a timely enough fashion.

Having a semi-continuous supply of tanks flying through space solves that problem, you just need refining capacity at the other end. The other detail is the tanks will be sent back in burst. If you have, say, 1000DTon tanks, you'll send all 25 back in one continuous burst.

I'd also employ at least 2 tugs at each end, simply for redundancy. Those tanks are waiting for anyone and if your one tug goes down for some reason, you can't easily stop the line while it's being fixed.

It is interesting, though, that we've never seen a ratio (at least I've never seen one) of refined fuel to unrefined fuel. If I start with 1000Dtons of unrefined, do I get 900Dtons refined? 800? 950?

I guess it's always been implied that the refining process happens during intake. For an operation like this, I guess it's simply a matter of where the slack in the line is as to where you'd put the refining capability.

But, either way, I think the real point is simply that for any large enough freight operation, the jump tank scenario makes sense. I haven't run the numbers, but it may even make sense to use tanks for Jumps as low at J2, almost certainly would for B5 J2 == 20% fuel mechanics (vs TNE).

Doesn't make sense for smaller freighters, but they're not profitable anyway.

The other thing that I think probably makes sense, expanding on this is basically "Cargo Riders", basically meta-container ships. In my 100Kton example, it had about 56Ktons for cargo. Turn that in to 10 5Kton "containers".

A ship jumps in, drops the containers, docks the outgoing set, and then jumps out with a 1-2 day turnaround. Tugs then take the containers in and out of planetary orbit, perhaps switch crews, etc. While the ship is in J-space and en route back, the containers are emptied and refillied to begin the cycle anew.

You lose some space to the grapples and what not on the mother ship, so you lose a wee bit of Cr/Cargo Ton efficiency, but I think you would make that up in overall time saved, and your expensive J-Drives have much higher utilization than once every 2 weeks.

 

[boomslang]

Originally posted by BetterThanLife:
OK Here is another situation for Drop Tanks. A Ship under 100 tons can't have a jump drive. Yet a Heavy Fighter or a Cutter can be equipped with Drop Tanks. Taking the tonnage over 100. Can it then jump? Can it drop the tanks and jump? If it has sufficient internal fuel tankage, can it then jump again without the tanks?

I was once a party to a design exercise along these lines on the ct-starships mailing list.

We cobbled together what was effectively a 100-dton (unsteamlined due to excessive displacememt) cutter module that had a j-drive (running off the cutter's "drive" and computer), its own 20-dton bridge (to meet displacement requirements for CT starships), and enough fuel to jump the whole carried package. I think we stuck some staterooms and a wee bit of hold space in there, too, since it had 30 dtons (a standard module's worth) of payload capacity available after it mounted the 20-dton basic cutter. (Our "jump sled" only really displaced 50 dtons on its own, and technically carried the cutter it was mounted to, not the other way around.) Our consensus was that as long as the whole assembly was at or over 100 dtons, it could jump. 2-G performance from the cutter it was bolted to, BTW.

(It was envisioned as a sort of cocoon that enveloped the cutter, thus elminating any objections about startship hulls having special jump networks that non-starship hulls lack.)

I would be inclined to disallow anything under 100 dtons jumping, which would include small craft that drop their tanks, but that's only because I am a staunch anti-j-torpedoist... YMMVIYTU...

There is a certain wistful, Euriskoish nostalgia to the idea of jump-capable small craft that drop their j-tanks upon arrival to gain agility for battle: "It's so crazy it just might work!" and all that.

Probably oughta make that mission volunteer-only, though...

 

[robject]

Here's a re-summary of all the drop-tank dreck I've dredged up.

Summary

To fit with those early bits of CT canon, drop tanks appear to be feasible from Day One, in a limited sense, i.e. as demountable external tanks. Prior to TL15, drop tanks could be carried into jumpspace to extend one's range, but they couldn't be used to directly fuel the jump drive.

Improvement came with TL15, apparently with better jump capacitors. It appears that jump capacitors can't hold their charge for long: first, the charge dissipates very quickly, and second, maintaining a continual charge on them must trash them. So perhaps at TL15 the charge could be held just long enough to allow using fuel from the drop tanks. (But: why not be able to use part of the fuel at lower TLs??)

(The "new" jump capacitors appear to be an enabling discovery; once they are learned about, they appear to be buildable at TL 9.)

From other discussions, it seems that the jump "fuel" is used up immediately prior to jump -- that's why drop tanks can work -- but the fuel is not converted into energy. Rather, the power plant (not the jump drive!) charges up the jump capacitors, while the jump "fuel" is used to do something related to forming a connection or entry point to jumpspace.

The TML debated on the timing of events here (in this instance, with droptanks), and the consensus seemed to be that the jumpfield was generated with a link to the ship, the tanks were then blown away, and the ship could then enter jumpspace through the created portal. There were opinions on every side.

Finally, no known drop tanks are reusable. They are damaged in the process: either the separation from the ship is traumatic, or they fall into the wake of jumpspace (how dramatic!), or something else happens. However, reusable droptanks don't automatically destroy a setting, and do assume a very stable interstellar infrastructure. But if droptanks are reusable, then why not dispatch a set of fuel cutters to serve tankless liners?


Corporate Example

The canonical example is the Trimkhana-Brilliance, an 800-ton Tukera Liner running on perhaps 4 drop tanks (80 tons each).

My assumption is that it serves in place of the 1000-ton Arean Lines transport, and with even more capacity. If so, it would require 320 tons of fuel, i.e. four 80-ton L-HYD tanks.

My next assumption is that reusable drop tanks cost approximately the same as a ship hull, i.e. MCr0.1 per ton.

</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;">(800) Hull MCr 80
14 Bridge -
85 Jump drive-M 160
8 M-drive-D 32
16 Power plant,8ep 32
8 Plant fuel -
-- No internal jump fuel --
52 20 Crew/14 SR 7
400 Pass/100 SR 50
217 Cargo -
-------------------------------
Drop Tanks(4x80) 32
-------------------------------
MCr 383</pre>[/QUOTE]

 

[Whipsnade]

Gents,

Re: Drop tanks

Which commercial airlines perform in-flight refueling?

It's feasible, it's done all the time, it extends the range of aircraft, but...

Which commercial airlines perform in-flight refueling?

That's the take on drop tanks IMTU.


Have fun,
Bill

 

[whartung]

Originally posted by Bill Cameron:
Gents,

Re: Drop tanks

Which commercial airlines perform in-flight refueling?

It's feasible, it's done all the time, it extends the range of aircraft, but...

Which commercial airlines perform in-flight refueling?

That's the take on drop tanks IMTU.

Well, the fundamentals all come down to economics. For good or ill, our economics come out of the pages of game books rather than any real market forces.

But beyond that, there's a reason commercial airlines don't provide in-flight refueling. First off, it's simply not necessary due to the limited distances we travel. The tradeoffs vs payload capacity, flight time, safety, etc. just don't warrant in-flight refueling for commercial aircraft. It's the same reason there's no push for supoersonic commercial aircraft. They're simply unnecessary, particularly in todays era of electronic commmunication.

The second major point tho is simply that staging mid-flight refueling operations is quite expensive. There's no difference between a 747 filled with fuel and one filled with passengers. The machines are essentially identical.

Compare that to a Jump ship, where the J-Drive is the primary component of cost in the ship vs a sub-light ship. The tankers here are dirt cheap vs a star-drive equipped ship. The expense (and value for that matter) of interstellar cargo is that leap through jump space. So there's value in maximizing the cargo/per Jump for a cargo ship.

The other part is that the fuel consumed by an aircraft is linear. It burns it up based on how far it travels. But on a Jump ship, that fuel is not linear. It's consumed all at once, and its consumed BEFORE the Jump. So any jump capable ship is always moving a large amount of empty volume through jump space.

But since everything about the ships major systems is based on volume, that empty space is very expensive. It's only value is simply as the enabler of the Jump at all.

If that requirement is removed, tho, if you no longer need to move empty holds through jump space, then your return/displacement ton is MUCH higher.

If a commercial airliner could readily, and cheaply swap out excess fuel capacity for cargo capacity for select flights, they would do so. But apparently they can't. For whatever reason, someone like FedEx doesn't task Boeing with giving them a larger capacity 747 with a fuel load to get them only from Los Angeles to Memphis, rather than from New York to Paris. No doubt there are all sorts of intangibles involved with converting the unused fuel space in to cargo space.

But I can assure you that they don't fill the tanks with fuel if they don't have too. There's no reason why FedEx needs to ship fuel from L.A. to Memphis, when Exxon will do it for them cheaper over land. So, whatever fuel they need for the trip is how much they'll carry.

In the same light, if a interstellar shipping operator doesn't have to move empty space through jump space, he won't.

So, given the economics and design sequences presented by TNE, using tankers at the Jump point to charge up the J-Drive of the starship is much, much more cost effective than carrying empty tanks through jump space, despite the large infrastructure involved in setting up the external fuelling operation.

 

[Whipsnade]

Originally posted by whartung:
So, given the economics and design sequences presented by TNE, using tankers at the Jump point to charge up the J-Drive of the starship is much, much more cost effective than carrying empty tanks through jump space, despite the large infrastructure involved in setting up the external fuelling operation.

Whartung,

The OTU has over 6000 years of jump drive use by humaniti and yet drop tanks are not the norm despite their 'obvious' cost effectiveness. I mean, it's cost effective and the Vilani weren't all over it like white on rice?

So, there has to be some reason that overshadows that cost effectiveness. Perhaps the reason is that large explosions happen too often for insurance carriers to swallow when drop tanks are used?

There's got to be some reason beyond your ship design spreadsheets.

In the same light, if a interstellar shipping operator doesn't have to move empty space through jump space, he won't.

Yeah, he doesn't move empty space except when he does. Tell me, do your players always jump with a full hold and full passenger cabins?

To paraphrase a certain melancholy Dane; There are more variables dreamed of in the OTU than found in your spreadsheets, Whartung.


Have fun,
Bill

 

[aramis]

Canon states that they were not even discovered to be useable until the 1000's, Bill.

Mind you, FF&S 2 included them, as did many T4 designers on the net, but....

 

[rancke]

Originally posted by Bill Cameron:
The OTU has over 6000 years of jump drive use by humaniti and yet drop tanks are not the norm despite their 'obvious' cost effectiveness. I mean, it's cost effective and the Vilani weren't all over it like white on rice?

So, there has to be some reason that overshadows that cost effectiveness. Perhaps the reason is that large explosions happen too often for insurance carriers to swallow when drop tanks are used?

The capacitors that makes drop tanks possible were not invented until late 11th Century. Once they were invented, they can be built at TL 9 (well, the rules certainly don't impose a TL limit).

I've always assumed that the Trimkhana Brilliance came from a world (probably Rhylanor) that already had drop tank liner service from another world (Mora) that had connections back towards the Imperial core. The reason drop tank use isn't all over the Regina subsector in 1105 is that the infrastructure is still being built up.

Then the TB disaster had the same effect on drop tank liners that the Hindenburg had on zeppelins. Or possibly the disaster revealed a real, hitherto unsuspected (or ignored) flaw in the technology...


Hans

 

[robject]

Reasonable.

 

[Whipsnade]

Originally posted by rancke:
Then the TB disaster had the same effect on drop tank liners that the Hindenburg had on zeppelins. Or possibly the disaster revealed a real, hitherto unsuspected (or ignored) flaw in the technology...

Hans,

Exactly.

The reason for the seeming 'lack' of drop tank fueled merchants and liners exists outside of our ship design spreadsheets.


Have fun,
Bill

 

[mike wightman]

The TL of drop tanks is given in High Guard first edition as TL12.

The other explanation for the drop tank failure on the Trimkhana Brilliance is deliberate saboutage - either Ine Givar or Oberlindes Lines sponsored covert trade war (sounds like a job for a group of PCs... ).

 

[whartung]

Originally posted by Bill Cameron:

The OTU has over 6000 years of jump drive use by humaniti and yet drop tanks are not the norm despite their 'obvious' cost effectiveness. I mean, it's cost effective and the Vilani weren't all over it like white on rice?

Maybe, but that wasn't the argument you presented, was it Bill? It's not even close. Your argument was trying to correlate the use of drop tanks by far future starship mercantile guilds to how modern airlines work.

I posited why that comparison doesn't hold L-Hyd.

So, there has to be some reason that overshadows that cost effectiveness. Perhaps the reason is that large explosions happen too often for insurance carriers to swallow when drop tanks are used?

Perhaps. But I've never seen a failure rate, die roll, or DM modifier affecting such a task as jetisoning drop tanks, so I can't really judge the risk one way or the other, can I? At least not in any definative sense vs. an IMTU thing.

Who's to say whether drop tanks are any more risky than the Jump itself? Even today sea and air travel is "safe enough", but hardly "completely safe".

</font><blockquote>quote:</font><hr />In the same light, if a interstellar shipping operator doesn't have to move empty space through jump space, he won't.

Yeah, he doesn't move empty space except when he does. Tell me, do your players always jump with a full hold and full passenger cabins?
</font>[/QUOTE]*sigh*

The reason a ship jumps with empty cargo or passenger cabins is because they have other factors demanding the jump, such as already taking on some passengers or freight with a promised delivery, or perhaps a schedule, or some other overriding business or personal concern. Perhaps their kids are having a birthday party. Who knows.

But at that point, for whatever reason, clearly waiting for full hold or passenger complement is not as important to the merchant as making the trip, thus they fly with empty holds or cabins.

An empty Jump Fuel tank, however, is a cost of doing business. A fixed expense. Just like a trucking company will buy more fuel efficient trucks if the numbers work out overall than if not, if a interstellar merchant didn't have to move those empty tanks through Jump space, they won't. If there was a viable, more efficient alternative, they'd use it.

Around here, all of the little delivery companies (like reprographic houses, etc.) use the smallest cars and pickups on the market, even though Hybrids like the Prius get better gas mileage.

Why is that? Because while a Prius may get better MPG, it doesn't do better dollars/mile than the smaller cars. The price of gas isn't the sole contributor to the cost of the vehicle. The total cost of ownership for the task at hand is higher for a Prius than a small 4 cylinder compact car.

So Prius's go to the feel good crowd, or the folks that want a free ride in the car pool lane, despite its demonstrably better fuel mileage.

That's the market at work. That's what the market does.

If an engineer from MegaCorp A presents a solid plan regarding the use of tankers and fuel ships that can save operating costs, the company is going to give a serious look at it. The large carriers have the capital and long term return horizon to make the investment in infrastructure necessary to make this plan work.

This doesn't affect the tramp freighters of the Traveller universe, they are smallfry. They don't operate ships in the 100KTon range.

All I did was run the numbers, as given, to see if the scheme would work. It's a non-intuitive conclusion, but given the numbers of the TNE world and FF&S design sequences, the numbers DO work, and they work surprisingly well.

If there's an intangible risk of failure using external fuel, then fine, that TOO would affect the final numbers. But I haven't seen anything regarding that.

I will say, tho, that the scheme seems to have enough margin, because it is so much more efficient and cheaper than the conventional mechanism, that I could see a reasonable amount of capital being invested to solve and reduce any of those risks if possible.

To me, in operation, it all boils down to how fast the fuel is consumed in tons/minute, and making sure the ship has enough on board storage to meet the need of the final phases in enough time for the tanks/tankers to "get out of the way".

The farther away things need to be, or the faster the drive system consumes the fuel, the more fuel that is actually necessary on the ship. Just like Jump Capacitors store "Jump Energy" (or whatever), Fuel Tanks store Fuel Energy, and you only need enough fuel for the final phase of the jump sequence.

To paraphrase a certain melancholy Dane; There are more variables dreamed of in the OTU than found in your spreadsheets, Warthung.

Yes, there are, but since Traveller has history of being as "hard science" as practical, it's also "hard economics". If you want something to not happen in YTU, then make it either impossible or unprofitable.

But given the sources I cited, drop tanks are neither, and I think worth exploring. I think popping in to a small pocket empire that had this infrastructure in place would add interesting color to a campaign.

Finally, I assume that <i>Warthung</i> is merely a typo, even though it appears twice, rather than something else.

 

[robject]

Originally posted by whartung:

Who's to say whether drop tanks are any more risky than the Jump itself? Even today sea and air travel is "safe enough", but hardly "completely safe".

Given, of course, that the Trimkha's fate was indicative of a serious problem, and basically halted all (known) commercial droptanking in the Marches. It's a plot hook dropped into our laps, which, regardless of its cause, has the effect of making droptanks dangerous enough to completely stop commercial use, at least along frontier routes. But, we don't know anything more than that.

I love a good mystery, though.

Around here, all of the little delivery companies (like reprographic houses, etc.) use the smallest cars and pickups on the market, even though Hybrids like the Prius get better gas mileage.

Why is that? Because while a Prius may get better MPG, it doesn't do better dollars/mile than the smaller cars. The price of gas isn't the sole contributor to the cost of the vehicle. The total cost of ownership for the task at hand is higher for a Prius than a small 4 cylinder compact car.

ASIDE:

I'll note that they also want their "transport supply" in mass-volume-per-time to match demand as closely as possible for the same reason. Which is why I like to assume (and I do mean assume) that the Book 2 trade tables are useful indicators of interstellar traffic in the Marches.

Regardless of what the output of any of those fictional worlds really "is supposed to be".

Oh no, the same old cans of worms. Those worms are looking pretty mushy-dead by now.

All I did was run the numbers, as given, to see if the scheme would work. It's a non-intuitive conclusion, but given the numbers of the TNE world and FF&S design sequences, the numbers DO work, and they work surprisingly well.

I have no problem with this. I've never been able to wrap enough of my brain around TNE to become invested.

To me, in operation, it all boils down to how fast the fuel is consumed in tons/minute, and making sure the ship has enough on board storage to meet the need of the final phases in enough time for the tanks/tankers to "get out of the way".

If the tankers are smaller than the refuelled ship, the distance may be very short indeed. Jump Masking is one of the factors we're wrestling with in the T5 "Playtest" aka "Development" forum.

[...] since Traveller has history of being as "hard science" as practical, it's also "hard economics".

Non sequitur, though I understand the sentiment.

If you want something to not happen in YTU, then make it either impossible or unprofitable.

I agree that loopholes must be closed.

 

[Whipsnade]

Originally posted by whartung:
Maybe, but that wasn't the argument you presented, was it Bill? It's not even close.

Whartung,

The argument I presented was that, while in-flight refueling is safe enough for military organisations, it is not safe enough for commerical organisations.

When drop tanks are discussed, the Gazelle(1) is always the design used as an example of their feasibility. My argument is that the Gazelle is a warship and not a merchant, that militaries have different views of what is economical than shipping companies.

Finally, I assume that <i>Warthung</i> is merely a typo, even though it appears twice, rather than something else.

Not a typo. Instead it was stupidity on my part. I first 'read' the name incorrectly and then spelled it wrong twice. The spelling has now been corrected in the post in question.


Sincerely,
Bill

1 - The Gazelle is broken in several aspects, not the least of which is that it is at the same time a post-LBB:2 and pre-High Guard design.

 

[Scott Martin]

Originally posted by whartung:
Having a semi-continuous supply of tanks flying through space solves that problem, you just need refining capacity at the other end. The other detail is the tanks will be sent back in burst. If you have, say, 1000DTon tanks, you'll send all 25 back in one continuous burst.

Actually the refinery is at the "crude" end, which is a contrast to how you would think of our current oil distribution system. This makes more sense, because you don't need to have enough "Crude" accumulate at a point to make a refinery cost-effective, you have a whole *planet* that is made of crude, so do the refining there. About 1 container in 20 is "cargo" instead of fuel: refined hydrocarbons, inert gasses and ion-drive fuel are also salable commodities, and since the "refining" process needs to remove them anyway it's very little effort to seperate them out and save them for sale.

The other thing that I think probably makes sense, expanding on this is basically "Cargo Riders", basically meta-container ships. In my 100Kton example, it had about 56Ktons for cargo. Turn that in to 10 5Kton "containers".

A ship jumps in, drops the containers, docks the outgoing set, and then jumps out with a 1-2 day turnaround. Tugs then take the containers in and out of planetary orbit, perhaps switch crews, etc. While the ship is in J-space and en route back, the containers are emptied and refillied to begin the cycle anew.

You lose some space to the grapples and what not on the mother ship, so you lose a wee bit of Cr/Cargo Ton efficiency, but I think you would make that up in overall time saved, and your expensive J-Drives have much higher utilization than once every 2 weeks.

IMTU (what started all of this in the first place) I have "Jump tenders" that are up to a kilometer long and have a 10m x 10m cross section. They contain an "oversized" jump drive, a small fuel reserve, Ion propulsion and *lots* of grapples for 6m x 10m end sections along the "sides" and connectors on the "top" and "bottom" for drop tanks. Operation in "serviced" areas is to load up, initiate the jump and drop the tank(s). "Unserviced" areas retain one bank of tanks through jump, and use this fuel to return (retaining the tank on return, and reducing the "return" tonnage) although this is generally only done on military operations, since it's fairly cheap to drop off a fuel tanker and have a few tanks left in the other system to be filled in the month or so between visits.

Turnaround time can be as low as a few hours, since the arrival point is well known and the modules just need to be dropped and pushed out of the way, with "outgoing" cargo already on tugs waiting to be loaded. So just drop the "inbound" cargo in a clear direction, load the "outgoing" cargo and jump out, leaving the tugs to clean up while you wait the day or so for the next inbound transport.

This works IMTU because the jump entry / exit points are very constrained, and the time for transit is very well characterized (Jump takes from 2-10 days, but it always takes exactly the same amount of time between two "jump points" plus or minus minutes.)

Compare that to a Jump ship, where the J-Drive is the primary component of cost in the ship vs a sub-light ship. The tankers here are dirt cheap vs a star-drive equipped ship. The expense (and value for that matter) of interstellar cargo is that leap through jump space. So there's value in maximizing the cargo/per Jump for a cargo ship.

Actually that's one of my issues with the OTU: In CT the computer is generally more expensive than the jump drive, and when the OTU "Advanced" to TNE/T4 the computer was still a significant expense (which you couldn't skimp on for insystem ships, in CT you could have a small craft with a model/1 or even IIRC no computer at all doing pick up duty) but if you compared the actual cost of components, the jump drive was generally less than 20% of the cost of a starship, making the "savings" of Rider-type configurations fairly trivial. In point of fact, if you assumed that you had to pay for refined fuel, your monthly expenses significantly offset the cost of installing more capable (and in TNE more efficient) jump drives. This is especially true at Tl 9-12 where the cost of a power plant-1 is 2x the cost of your jump-1 drive, but higher TL's make power plants "cheaper" since they are the same cost/volume but more space efficient. Oversized J-Drives make more sense in TNE / T4 (or LBB2 for that matter) where you can
have a jump drive significantly larger than your power plant (so Jump-4 M-Drive-1 P Plant-1 is "legal")

The jump frames described earlier are about 20% J-Drive with a very small stationkeeping drive (about 1cm/sec/sec accelleration unloaded, or roughly 0.01G) and a smallish powerplant and batteries to power the actual jump. These give an effective Jump-4 for a LOT of cargo at very low cost, but they have absolutely no maneuver or defensive capability to speak of.

Scott Martin

 

[robject]

You know, Sigg always did think that High Guard sort of muddled up the drives section a bit.

 

[mike wightman]

Yup, I've flat out stated several times that I think there was a transcription error in first edition High Guard that swapped the jump drive and maneuver drive percentages. Swap them back and you are closer to the CT LBB2 numbers.

We've been stuck with the error ever since

 

[Scott Martin]

Doesn't change a J-1 ship, bus it makes a *significant* change (especially in cost) to ships with higher jump performance.


Hmmm...

Scott Martin

 

[robject]

Thread Resurrect

Currently, I'm considering a variant of an opinion I've heard from the TML about droptanks.

In short: when someone initiates a jump within 100 'diameters' of something else, the smaller thing suffers a mishap or takes critical damage or something.

This applies to everything. Drop tanks, ejected during jump initiation. Escape pods or vac-suited individuals who disconnect from the ship. Another ship. Asteroids. Whatever. And if your ship initiates jump too close to something bigger than it, your ship is the one to suffer the consequences, like always.

Yeah, it's a fancy handwave that brings up more questions. And it's theoretically exploitable, too.

Taken to extremes, if you jumped an entire planet, its moons and orbiting equipment would all be critically damaged, or misjump to the four winds, or something. And if that planet were within the 100D limit of its star, the planet itself would take damage or misjump. Etc.

 

[selunatic2397]

That seems to be a little harsh to me Robject.

It would let the missjumps happen so often that no one in their right mind would travel...all that spacejunk out there!

"Ooops! ya must have missed that little piece of rock...MISJUMP!!!"

Far too strict for me...if you don't want droptanks just don't use them...