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Author Topic: JumpShips YES, DropShips NO  (Read 3422 times)

Daryk

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JumpShips YES, DropShips NO
« on: 10 April 2019, 18:32:04 »
So... growing out of an idea up in General Discussion, what if the BattleTech universe developed JumpShips without the magical fusion engines that give us DropShips?

Initial thoughts:
Colonization of other star systems still happens.  The incentives are just too powerful.

Interstellar warfare is MUCH harder, and skews much further toward high density firepower (i.e., 'mechs).

The above puts more of a premium on information and irregular warfare, as the best way to get infantry (for all of their very necessary functions) is to recruit them locally.

WarShips may or may not exist.  The lack of efficient fusion rockets means they can't maneuver very well, or for any length of time, but capital scale weapons would still be useful for dominating jump points.  That said, bigger ships may be the most efficient way to get an invasion force to a planet.  The necessary fuel fraction will mean relatively light armament, though.

Planetary defenses will be much harder to crack.  For rich planets, it may mean go nuclear or go home.

Other thoughts are more than welcome!

Maingunnery

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Re: JumpShips YES, DropShips NO
« Reply #1 on: 10 April 2019, 18:41:53 »

What about Small Craft?
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monbvol

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Re: JumpShips YES, DropShips NO
« Reply #2 on: 10 April 2019, 18:54:41 »
Falcon Heavy is already listing a maximum payload of 64 tons to orbit in the real world.  So a 200 ton reusable shuttle is not out of the question in such a setting.

True ASFs would be more problematic really.  Mostly I'd just nix conventional fighters all together and prohibit ASFs from actually operating in space, handwaving the whole engine thing as much as possible.

Daryk

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Re: JumpShips YES, DropShips NO
« Reply #3 on: 10 April 2019, 19:12:32 »
Surface to orbit Small Craft wouldn't be too much of a problem, but long range ones would be right out.  Reaction mass is the main limiter.  ASFs could work, but again are very short legged.

monbvol

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Re: JumpShips YES, DropShips NO
« Reply #4 on: 10 April 2019, 20:00:09 »
It would still be very troublesome but it would make the idea of the Banshee actually a bit more reasonable.

Daryk

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Re: JumpShips YES, DropShips NO
« Reply #5 on: 10 April 2019, 20:02:55 »
A fast assault 'mech?  I'm trying to see the connection, but I'm not quite there yet...

monbvol

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Re: JumpShips YES, DropShips NO
« Reply #6 on: 10 April 2019, 20:12:06 »
The ASF that tried to mount two different engines Banshee, not the mech.

Sartris

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Re: JumpShips YES, DropShips NO
« Reply #7 on: 10 April 2019, 20:19:15 »
He with the mostbest asfs wins

Tai Dai Cultist

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Re: JumpShips YES, DropShips NO
« Reply #8 on: 10 April 2019, 21:43:59 »
So... growing out of an idea up in General Discussion, what if the BattleTech universe developed JumpShips without the magical fusion engines that give us DropShips?

If you just re-define the limitations imposed by gravity, you can replace Zenith/Nadir jump points with local Planet/Star system lagrange points.  Pretty much everything else can stay the same (e.g. Pirate points, etc) but with smaller interplanetary distances to cover between jump points and orbit, you don't need magic fusion drives.  As much, at least.

Daryk

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Re: JumpShips YES, DropShips NO
« Reply #9 on: 11 April 2019, 03:21:48 »
The ASF that tried to mount two different engines Banshee, not the mech.
Ah, hadn't seen that one before.  Thanks!

He with the mostbest asfs wins
Hmmm... so carriers will be necessary for an assault.  And they'd be big and slow in comparison (much like today's)… I'm liking it!

Easy

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Re: JumpShips YES, DropShips NO
« Reply #10 on: 11 April 2019, 10:04:00 »
cleanup
« Last Edit: 29 May 2019, 14:56:33 by Easy »

monbvol

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Re: JumpShips YES, DropShips NO
« Reply #11 on: 11 April 2019, 10:16:01 »
Strap enough rockets to something and anything can be put into orbit.   ;D

More realistically though chemical rocket power roughly in line with what we have now would severely limit ground to orbit lift capabilities compared to the standard setting.

In a way I think this would better represent the implied reality of early Battletech where it was heavily implied you needed notable advantages in terms of numbers, mass, or the combination of the two to stand up against Battlemechs with any hope for success when it comes to vehicles and infantry and I'll be honest I think the game needs to be more explicitly like that.

Elmoth

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Re: JumpShips YES, DropShips NO
« Reply #12 on: 11 April 2019, 10:21:10 »
If we do not have fusion power we do not have mechs either, right?...

monbvol

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Re: JumpShips YES, DropShips NO
« Reply #13 on: 11 April 2019, 10:48:57 »
Fusion power in of itself still exists, just not the physics breaking magic transit drives.

Tai Dai Cultist

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Re: JumpShips YES, DropShips NO
« Reply #14 on: 11 April 2019, 10:59:42 »
Yeah one ton of reaction mass moving tens of thousands of tons of dropship a half a G's worth of acceleration is magical.

And once you get into the hand-waiving involved in transit mode fuel consumption, that's even more magical than hyperspace jumps.

The_Caveman

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Re: JumpShips YES, DropShips NO
« Reply #15 on: 11 April 2019, 11:39:42 »
Yeah one ton of reaction mass moving tens of thousands of tons of dropship a half a G's worth of acceleration is magical.

And once you get into the hand-waiving involved in transit mode fuel consumption, that's even more magical than hyperspace jumps.

All could've been fixed early on if they'd made the construction rules for spacecraft more sensible. Fuel fractions are absurdly small, max armor on warships is basically a rounding error in terms of weight. And space combat trying to look like WW1 dogfights on a scale of thousands of kilometers...

Wait, somebody remind me what the "baby" we're trying not to throw out with the "bathwater" is here....
Half the fun of BattleTech is the mental gymnastics required to scientifically rationalize design choices made decades ago entirely based on the Rule of Cool.

The other half is a first-turn AC/2 shot TAC to your gyro that causes your Atlas to fall and smash its own cockpit... wait, I said fun didn't I?

monbvol

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Re: JumpShips YES, DropShips NO
« Reply #16 on: 11 April 2019, 12:35:41 »
A lot of problems with Battletech are nicely solved if heavy lift to orbit is a more major effort and likewise moving in space is a much more difficult undertaking.

Daryk

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Re: JumpShips YES, DropShips NO
« Reply #17 on: 11 April 2019, 15:11:31 »
The tweak I've always thought about putting in was to cut the transit drives down by a factor of 10 (i.e., "Station Keeping" is as good as it gets).  Tactical fuel consumption is roughly high enough as is, I think.

Charistoph

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Re: JumpShips YES, DropShips NO
« Reply #18 on: 14 April 2019, 00:44:04 »
Odds are, if one does not have the transit drives for Dropships, then ASFs and Small Craft as we know them would be closer to Conventional Fighters.  Fighters would either be void-based or atmo-based, and woe to the pilot that confuses them.

Dropships would still exist, but they would literally be focused on transitioning between surface and orbit, and little else, while another ship-type would be focusing on transitioning from orbit to Jump Point.

As others have stated, the idea of Warships would be painful to consider.
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The_Caveman

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Re: JumpShips YES, DropShips NO
« Reply #19 on: 14 April 2019, 20:46:06 »
Odds are, if one does not have the transit drives for Dropships, then ASFs and Small Craft as we know them would be closer to Conventional Fighters.  Fighters would either be void-based or atmo-based, and woe to the pilot that confuses them.

Dropships would still exist, but they would literally be focused on transitioning between surface and orbit, and little else, while another ship-type would be focusing on transitioning from orbit to Jump Point.

As others have stated, the idea of Warships would be painful to consider.

WarShips would be essentially spaceborne mobile fortresses for taking/holding jump points (with the greatly increased importance of LaGrange points due to long transit times, this actually matters now). Battle doctrine would involve sending in the WS first to establish a beachhead at the jump point, then bring in the larger JS fleet with the troop and fighter carriers as part of the second wave once the enemy's defenses were committed. The sheer size and thick PD screens of WarShips would give them the staying power to hold the jump point while forces inserted and returned. No one in their right mind would send a WarShip near a planet.

Which actually gives them a *role* unlike the current paradigm where they are either ludicrously expensive transport JumpShips or irreplaceable nuke-magnets serving the same role as a fleet of assault DropShips.

DropShips would become primarily shuttle or fighter carriers, with a need arising for short-range small craft capable of inserting 'Mechs to the surface and retrieving them. The current-standard 150-ton 'Mech bay would have to go away, at least for small craft, or the maximum size of small craft would need to be bumped to 3-400 tons. Assault DropShips would be the centerpieces of planetary defense fleets, but not something you bring along on an offensive sortie because fuel burn would be prohibitive. Your carrier DropShips would be left in low orbit where they wouldn't need to burn precious fuel, and function as flying supply depots for shuttles to dock with.

I agree with the splitting of fighters into two roles. You would have primarily space-based fighters with large fuel fractions, low-to-medium thrust and long-range weapons, which would escort DropShips and protect high orbits and LaGrange points. And you would have primarily atmospheric fighters with high acceleration, heavy short-range firepower, and less loiter time, whose job would be to scramble and intercept shuttles coming down from low orbit, and then to support the ground battle. This second group would consist of both ASF and CF in a high/low mix, with the ASF attempting to stop invaders prior to reentry and the CF wings mopping up anything that got through.
Half the fun of BattleTech is the mental gymnastics required to scientifically rationalize design choices made decades ago entirely based on the Rule of Cool.

The other half is a first-turn AC/2 shot TAC to your gyro that causes your Atlas to fall and smash its own cockpit... wait, I said fun didn't I?

idea weenie

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Re: JumpShips YES, DropShips NO
« Reply #20 on: 14 April 2019, 22:34:33 »
One thing to consider is that offensive/exploration Jumpships would want to have astronomical gear and good computers on board, to try and spot any Pirate points.  Instead of spending ~10 days to transit from Jump point to target planet, the Jumpship would arrive in-system, plot a pirate point while charging, jump to that pirate point, and then launch the invasion/raiding force.  If you are raiding, you should have the rough dates, and a good enough astronomy database will tell you where the target planet is.

Surveying a brand new system would be difficult as you need to figure out the plane of the system, and from there you have to search the doughnut to try and find an inhabitable planet (star emissions can be observed, and the Goldilocks zone calculated easily).  As a result, there would be a demand for old Star League charts, as those would have most of the survey data already present.

Trade would be conducted in a similar manner, but with freighters contacting an HPG center to crunch the numbers needed for a Pirate Point to Pirate Point jump.  So whoever is in control of communications would wield massive economic power.  Comstar might even as a courtesy send a notification to the receiving system that a freighter was inbound, along with its rough description (and if the Jumpship keeps providing the wrong description, they are fined and eventually blacklisted).  This means whenever a planet change hands, this disrupts the trade greatly as the existing networks are not just politically severed, but trading Jumpships often can't get easy access to the system as well.  So new networks have to be developed in the capturing empire's region, and in the meantime the planet is trying to make something work.  Expect border worlds that trade sides often to be very self-sufficient because of this.  Not high-tech, just self-sufficient.

Giovanni Blasini

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Re: JumpShips YES, DropShips NO
« Reply #21 on: 14 April 2019, 23:00:40 »
I actually played around several times with this kind of idea, and began redoing the SLDF WarShips with realistic fusion engines and fuel tanks. It was also a staple of Cray's non-canon Battletech 2100/2200 setting.

Oddly enough, it's not as awful to do as you would think, though the Union becomes your lance transport and the Overlord your company transport. The cap on how big you can be and realistically land also has a major effect on deployments.
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Daryk

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Re: JumpShips YES, DropShips NO
« Reply #22 on: 15 April 2019, 03:25:35 »
I actually played around several times with this kind of idea, and began redoing the SLDF WarShips with realistic fusion engines and fuel tanks. It was also a staple of Cray's non-canon Battletech 2100/2200 setting.
*snip*
Is that still around here somewhere?  Do you have a link?

Hptm. Streiger

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Re: JumpShips YES, DropShips NO
« Reply #23 on: 15 April 2019, 03:38:04 »
Can't be the fuel (water) be broken up into hydrogen for the park/transit drive? Same water can be used to increase thrust for tactical movement, according to atomic rockets.
However, you still have to drop the maximum thrust by a great margin.
What I have problems with is the landing - who is so suicidal to defend his home turf by shooting down drop-ships. not to mention that their engine will shoot a lot of radiation-death into my atmosphere. (Ok maybe it can be reconfigured for atmosphere flight by making the engines close cycle and suck in some atmosphere, for ram-jets)



The_Caveman

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Re: JumpShips YES, DropShips NO
« Reply #24 on: 15 April 2019, 07:10:10 »
Fusion engines don't produce radioactive exhaust.

Not the way fission engines do, that is. The exhaust itself is hot enough to emit x-rays but once it cools it isn't going to poison the atmosphere like a high-power NERVA rocket.
Half the fun of BattleTech is the mental gymnastics required to scientifically rationalize design choices made decades ago entirely based on the Rule of Cool.

The other half is a first-turn AC/2 shot TAC to your gyro that causes your Atlas to fall and smash its own cockpit... wait, I said fun didn't I?

VhenRa

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Re: JumpShips YES, DropShips NO
« Reply #25 on: 18 April 2019, 00:26:42 »
Fusion engines don't produce radioactive exhaust.

Not the way fission engines do, that is. The exhaust itself is hot enough to emit x-rays but once it cools it isn't going to poison the atmosphere like a high-power NERVA rocket.

Even a NERVA isn't too bad. A Gas Core Open Cycle on the other hand....

Giovanni Blasini

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Re: JumpShips YES, DropShips NO
« Reply #26 on: 18 April 2019, 12:05:08 »
Is that still around here somewhere?  Do you have a link?

Buried on half a dozen different hard drives, PCs and thumb drives, at least.  Not online anymore.
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Alsadius

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Re: JumpShips YES, DropShips NO
« Reply #27 on: 18 April 2019, 12:32:20 »
Is that still around here somewhere?  Do you have a link?

Not the same version, but there was a discussion about this last summer that may be of interest: https://bg.battletech.com/forums/index.php?topic=62209.msg1428784#msg1428784 tl;dr, if you use tactical fuel consumption on a typical WarShip, the mass spent on fuel is fairly realistic by sci-fi standards (the linked post may have been optimistic - I think someone took me to task in another thread for missing an important part of the math - but it's at least close enough to feel like you're being good about realism).

Daryk

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Re: JumpShips YES, DropShips NO
« Reply #28 on: 18 April 2019, 16:47:31 »
Yep, I was in that thread too.  And I stand by what I posted back then: reduce transit drives to station keeping thrust(divide by 10), and leave tactical consumption alone.  That's MUCH closer to "right" than what we have now.

Maingunnery

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Re: JumpShips YES, DropShips NO
« Reply #29 on: 18 April 2019, 16:56:23 »

Just handwave it as the fusion torches drawing extra energy from hyperspace.  ;D
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