Getting to the Moon at TL9

[AlexanderHowl]

I think that, from a practical point of view, you would require armor on any section that contains a volatile system for safety reasons (which fuel tanks that carry HEDM most definitely are). Likewise, I do not think that spacecraft that have volatile systems would be allowed smaller control rooms for safety reasons, as inferior handling means more accidents. Concerning safety, once again, you would need a second rocket or a soft-landing system to allow people to survive in case of primary rocket failure during liftoff (not a necessity for automated cargo vehicles, but mandatory for crewed passenger vehicles).

Hanger bays allow for quick transfer of cargo and passengers, especially if your location does not have a hanger bay to receive your spacecraft, which impacts turn around time. For example, it is easier to transfer a passenger capsule than to having passengers cycle through an airlock every time they make a transfer. In the case of cargo, hanger bays also allow larger individual pieces through than cargo bays, with SM-3 being the largest for hanger bays and SM-4 being the largest for cargo bays.

If you went with the stripped down version, an accident that ended up costing human lives would have the company sued six ways to Sunday for negligence, and it would be up to its eyeballs in government investigations. Of course, companies would likely attempt a strip down version first, so you could have a campaign where a nascent lunar colony has to survive after the company is forbidden from using its HEDM rockets to supply them, requiring them to depend on local resources. Nitrogen would be a real problem, as a SM+10 mining unit would only produce a maximum of 10 pounds per hour as a byproduct of processing, and humans require a lot of nitrogen for life support (not only in the breathing mixture, but also for the production of food).

[Varyon]

Originally Posted by AlexanderHowl

I think that, from a practical point of view, you would require armor on any section that contains a volatile system for safety reasons (which fuel tanks that carry HEDM most definitely are). Likewise, I do not think that spacecraft that have volatile systems would be allowed smaller control rooms for safety reasons, as inferior handling means more accidents. Concerning safety, once again, you would need a second rocket or a soft-landing system to allow people to survive in case of primary rocket failure during liftoff (not a necessity for automated cargo vehicles, but mandatory for crewed passenger vehicles).

The risk of impactors that might sufficiently damage a fuel tank to cause HEDM to explode isn't a factor until you reach orbit (where you need to worry about orbital debris, micrometeorites, etc), and you're out of fuel once you're in orbit so that's not an issue. A smaller control room impacts Hnd because you have insufficient maneuvering thrusters/gyros, but you aren't using those during lift-off, so it's not an issue.

In any case, all of the above problems don't matter for cargo (yes, there's a small risk of loss, but unless my design results in you losing every other shipment, you're still coming out ahead). For people - who are probably the least by weight cargo you'll be shipping - feel free to use up some of the cargo space for armor, larger soft landing systems, a larger control room, passenger seating, etc.

Originally Posted by AlexanderHowl

Hanger bays allow for quick transfer of cargo and passengers, especially if your location does not have a hanger bay to receive your spacecraft, which impacts turn around time. For example, it is easier to transfer a passenger capsule than to having passengers cycle through an airlock every time they make a transfer. In the case of cargo, hanger bays also allow larger individual pieces through than cargo bays, with SM-3 being the largest for hanger bays and SM-4 being the largest for cargo bays.

I don't see anywhere in Spaceships where it actually states cargo in a hangar bay can be unloaded more quickly (the speed appears to be entirely dependent on the facilities at the destination - see SS1:44). Additionally, skilled workers (which may be robots, depending on tech assumptions) can maneuver just as large of objects through cargo bay doors as through hangar bay doors (SS1:42). Hangar bays are a waste of resources for our purposes.

Also, if we do assume the 1 man-hour per 100 tons figure is appropriate for unloading from hangar bays, how much time does that actually reduce? The heaviest-at-launch spacecraft I can find was the space shuttle Atlantis during STS-117. That was around 2,000 tons, or SM+9. Let's say we go one SM higher than that, for SM+10. My design gives around 45% as payload, for 4,500 tons. That takes 450 man-hours, or 150 hours (16.7 work days, assuming 9 hours of work each day) for a small 3-man team. If we replace our cargo bays with hangar bays, we reduce payload to only 2,700 tons, but that only takes 27 man-hours - 9 hours (1 9-hour work-day) for a small 3-man team. How much time do you suppose it takes to get a vessel ready for launch? 1 day per 1,000 tons of total vessel weight would be pretty fast, but let's go with that, for 10 days. Every 1 launch of the cargo version delivers as much payload as 1.67 launches of the hangar version, so we're looking at something like 27 (rounding up) days for the cargo version to deliver 4,500 tons, 18.3 days (16.67 days prep, 1.67 days unloading) for the hangar version. That's not worth the additional expense. Maintenance after each launch for those hangar bays cost $3.15M - $1.17k per ton of payload - and you're launching 1.67x as often, increasing cost per ton by another $6.2k/ton or $3.2k/ton, depending on launch method. Total cost for the hangar version is $16.67k/ton or $9.17k/ton, as opposed to $9.2k/ton or $4.8k/ton. I don't think that's worth saving a few days. Maybe if you're launching so frequently your rate determining step is unloading (meaning you can launch an SM+10 vessel every day, yet still only have 3 people doing the unloading in orbit), but that seems unlikely.

EDIT: I made a few math errors above, those should all be corrected now. More importantly, there's a question of the speed of emptying a cargo bay. The rules for the hangar bay give a rate at which it can launch vessels (for our SM+10, this is up to 300 tons per minute - 100 tons per minute per hull section, and I assume with 9 systems we could spread it amongst all three hull sections). However, SS1:44 states that moving a vessel around in a hangar bay uses the 10 tons per man-hour value instead. This implies that, while the bays can empty quickly, you have to move the vessels (or, in this case, cargo) into position manually to let the hangar machinery work to move it out of the vessel. If you can have all of your cargo already set and ready to be tossed out, you can manage it in 9 minutes. If we instead assume the hangars are only able to have ready to launch at once the largest vessel they can actually launch, that means the first 900 tons (each hull section could fit a 300 ton vessel - SM+7 - through its doors) can be launched in 3 minutes, but the remaining 1,800 tons take 180 man-hours - 60 hours (6.67 days, for 9-hour workdays) for a 3-man crew - because that's how long it takes to load the remaining cargo onto the launchers. That means we're looking at 27 days (and one trip) for the cargo version to deliver 4,500 tons, 27.78 days (and 1.67 trips) for the hangar version.

[Flyndaran]

Safety is a cultural issue. It's perfectly plausible to have some societies accept risk that would appall us, and others that are equally appalled by us.

You could even have a disconnect between planet-bound and Luna-bound groups' view of acceptable risk. Short time frames of set up may not matter due to the major self selecting bias of colonists.

[TGLS]

Originally Posted by Varyon

With the Winged feature, you technically don't need a high thrust to escape into orbit - you just need enough thrust to generate lift. Sadly, I don't know how to calculate stall speed for such aircraft - if you know how, divide that by 2,500 mph and square the result to find what acceleration, in G's, is your minimum.

Well, there's an alternative option. Instead of using some kind of space-plane or rocket to reach orbit, instead you could use a ridiculously large airship. The static lift provided by the airship would offset the low acceleration of the higher efficiency drives, allowing for a cheaper to orbit cost. While Spaceships 7 calls gasbags on SM +10 ships superscience, at least one company is apparently seriously proposing this (JP Aerospace).

[Fred Brackin]

Originally Posted by TGLS

While Spaceships 7 calls gasbags on SM +10 ships superscience, at least one company is apparently seriously proposing this (JP Aerospace).

The last 40 years of airship (non)development indicates that such proposals should not be taken seriously.

[AlexanderHowl]

Originally Posted by Fred Brackin

The last 40 years of airship (non)development indicates that such proposals should not be taken seriously.

I have to agree. It is a bit like anyone who suggests space elevators or Earth-based orbital mass drivers, it will not happen. It may be an interesting idea, but reality murders such ideas and does not bother to hide the bodies.

[Anthony]

Originally Posted by AlexanderHowl

I think that, from a practical point of view, you would require armor on any section that contains a volatile system for safety reasons

Reality doesn't agree with you. Ordinary rocket fuel tanks are perfectly capable of exploding (and do so every so often) and are not armored. Instead, you have a combination of "be very careful" and "locate your launch facility somewhere where a rocket blowing up won't do too much damage"

Originally Posted by AlexanderHowl

If you went with the stripped down version, an accident that ended up costing human lives would have the company sued six ways to Sunday for negligence

Accidents that kill people happen in industry. It costs money, but it doesn't stop people from doing those things as long those things are valuable enough to cover the losses. In any case, you can assume cargo launches will be automated with no crew.

[Rupert]

Originally Posted by AlexanderHowl

I think that, from a practical point of view, you would require armor on any section that contains a volatile system for safety reasons (which fuel tanks that carry HEDM most definitely are). Likewise, I do not think that spacecraft that have volatile systems would be allowed smaller control rooms for safety reasons, as inferior handling means more accidents. Concerning safety, once again, you would need a second rocket or a soft-landing system to allow people to survive in case of primary rocket failure during liftoff (not a necessity for automated cargo vehicles, but mandatory for crewed passenger vehicles).

That would be the addition of Emergency Ejection to the Control Room, which if it's two sizes smaller should be legal on a SM+10 ship. As for armour - that's not how we build rockets today, and it never has been, and it's not going to stop most accidents that cause the HEDM fuel to blow anyway.

Hanger bays allow for quick transfer of cargo and passengers, especially if your location does not have a hanger bay to receive your spacecraft, which impacts turn around time. For example, it is easier to transfer a passenger capsule than to having passengers cycle through an airlock every time they make a transfer. In the case of cargo, hanger bays also allow larger individual pieces through than cargo bays, with SM-3 being the largest for hanger bays and SM-4 being the largest for cargo bays.

Actually, you can fit just as large an item through a cargo hatch, as long as you're careful. As for turn-around time, why are you in such a hurry? Refueling and pre-flight checks will be taking a lot of time anyway. The reduced turn-around time is not going to recover the cost of losing 40% of your carrying capacity. As for passenger transfers - you shouldn't need to cycle them through the airlock - use a Passage Tube.

I feel like you're setting

If you went with the stripped down version, an accident that ended up costing human lives would have the company sued six ways to Sunday for negligence, and it would be up to its eyeballs in government investigations. Of course, companies would likely attempt a strip down version first, so you could have a campaign where a nascent lunar colony has to survive after the company is forbidden from using its HEDM rockets to supply them, requiring them to depend on local resources. Nitrogen would be a real problem, as a SM+10 mining unit would only produce a maximum of 10 pounds per hour as a byproduct of processing, and humans require a lot of nitrogen for life support (not only in the breathing mixture, but also for the production of food).

Per SS, you don't need to be doing that - total life support or sufficient open spaces will do.

I feel like you're setting up all these conditions and constraints like you're looking to prove that this can't be done. Perhaps it would be better to see how it can be done using the rules (as that's what you've said you want to do), and then see how much 'slop' there is that can be used up in safety features and frills. Or, if the price per person/pound comes out too low using 'on the cheap' builds, you should then add in annoying safety regulations until the price is high enough to suit.

[hal]

Originally Posted by Rupert

... Perhaps it would be better to see how it can be done using the rules (as that's what you've said you want to do), and then see how much 'slop' there is that can be used up in safety features and frills. Or, if the price per person/pound comes out too low using 'on the cheap' builds, you should then add in annoying safety regulations until the price is high enough to suit.

That is what I've always liked about having a system to explore things and figure out what is or is not possible by the constraints of the "system".

What intrigued me most about the idea of a TL 9 lunar colony was the concept of "how do I fill in the missing bits". For instance, suppose I wanted to build a maglev accelerator to loft half ton lots into lunar low orbit. I want to be able to collect those half ton lots so they can be transported by the Magsail tug, back to High Earth Orbit where they will be used for the construction of a space station.

Problem is - we need all those specialized manufactured parts - brought up out of Earth's Gravity well and sent to the Moon. Could we send up factory modules into orbit around the Moon, keep it in a lunastationary orbit just shy of the dark side of the moon? If so, would it be worth considering the prospect of using the Moon to shield it from Solar Flares? Would cosmic Radiation force the stations to have more "rock Shielding" just to make long term life aboard the stations viable? Maybe we rotate personnel on/off the stations to keep the radiation doses tolerable for long term use?

If we don't have perfect life support that is self-replenishing, then we need to have constant supply runs. If we do have those magleg catapults, then we need to insure that those don't become weapons against the home world. Perhaps the maglev's point of aim is such that it can never send any payload directly at Earth, which is why a low Lunar orbit works?

Part of me would LOVE to build a game setting based on those particular conjectures. While I sort of like the TRANSHUMAN SPACE ship building rules, I kind of get turned off by all of the massive genetic engineering and the introduction of ubiquitous AI proliferation. What happens when you kill the power to an AI? Does it perish? Does it hibernate and then spring into full functionality when the power returns? What happens when sufficient blocks of humanity can no longer actively participate in the economy due to lost jobs that the AIs now handle? What happens when manual labor performed by humans can be taken over by robotic labor - at a cheaper price than a human needs to survive?

All of these "things" were glossed over, which is why I never ran a Transhuman Space campaign despite buying 80% of the books the line produced.

If Elon Musk were to have his way, we'd be on Mars already. In 30 years, his dream may be realized. I hope I live long enough to see the first ever Mars Landing by humanity.

It would be a disappointment were I to die and it hadn't happened...