Sending Stuff to Mars

[Will Fawkes]

Alright. Colonies on Mars need parts that cannot be built on site because reasons and I basically have been nonspecific in the last story what this is.

Say parts can now be manufactured. Given this is America and Kennedy is trashed. Best way to get into orbit? Even if it's a flash forward five or so years down the road as new facilities are built.

I'm thinking setting is Midwest, but if need be could have the launch site moved wherever I suppose.

Target is Olympus Mons and while I know there are specific launch windows to get there in six months isn't the usual wait time closer to two years?

I would model this in KSP but I can't run it.

No idea how much cargo can go up per launch and I have a little wiggle room. Maybe it was parts the governments I intentionally made sure colonies couldn't make home grown with their equipment so they can't break away and once they gain that ability it's self sustaining. Mars has more or less the same stuff Earth has right?

Basically small earth freeze dried and no real global magnetic field to speak of.

While I could just have the parts to make this plotanium device to make widgets be any size I want to give some kind of credibility to the whole thing.

Important detail. Life after people. Population... Robots. Turns out a lot of the helper bots that exist, ranging from mouse catchers to assisted care droids, to smart vehicles are now self aware. This leaves a ot of infrastructure trashed so there is a lot of rebuilding.

Thankfully there is an automated factory that, thanks to mars, now has plans to build things that will get the factory more space to build other things needed to make the way to get widgets back to Mars.

Advice?

[Nibb31]

I'm not quite sure what you're asking for here? Try writing full sentences with proper verbs instead of asking us to fill in the blanks and try to guess what you're trying to say.

Target is Olympus Mons and while I know there are specific launch windows to get there in six months isn't the usual wait time closer to two years?

The typical launch windows for Mars are approximately every 2 years with a transit time of 6 months. You could launch at other times, but it would need more delta-v and the transit time would be longer.

[peadar1987]

Also, Olympus Mons would probably be a bad place to try and land. You're giving yourself 22km less height and atmosphere to shed speed.

[Dkmdlb]

If it has to be in the midwest, your best bet is to put a launch site on the Gulf Coast in Texas - maybe SpaceX's site near Brownsville? Maybe a SLS sized rocket is available. If yes, you can send up 70 tons per launch. Launch 70 tons of supplies, dock it to a 70 ton transfer stage in LEO, and head to Mars. If you only have a Falcon Heavy, you are limited to 50 tons per launch, if you only have a delta heavy you are limited to 28 or something.

But all this assumes a near future setting. I have no idea what the heck you are trying to do because full sentences, so I don't know if this will work for you. If there are no people, and there are manufacturing robots, then it doesn't really matter where you launch. Send up a 200 ton to LEO rocket from downtown Chicago if you want. It doesn't matter.

[Kryten]

Windows for Mars transfer are every eighteen months; specific orbit doesn't really matter. Largest rocket in vaguely near-future setting are SLS (120 tons to LEO in largest config) Yenisei-5/Kaskad/Amur-5/WhateverRKKEnrgiya'sproposalendsupbeing (all about 125 tons) and possibly CZ-9 (100-150 tons to LEO, depending on chosen design). Obviously only one of these is american, but I don't see the other two standing still in this situation.

[Will Fawkes]

I was actually going for 'near enough future the hardware is recognizable' so while I can cheat a little, I was actually thinking of space x's falcon as a goal. Idea I have now is there are salvageable SLS heavies (near future version maybe getting 100 tons up as a nice round number) per launch before having to fall back on a lighter design since can't make the big ones.

So say five sls-type rockets going up for BIG stuff and then having to work around smaller payload sizes.

There is a moon colony and orbital support structure that can act as way station for top off, but what would the idea be: Send the big things up that end up as the actual vehicle all the smaller loads get piled into and shuttled to Mars in before getting bouncy-balled down Olympus Mons for pickup?

Going American because the colonies only sent, so far as the books are concerned, one probe with a trio of robots (one from each colony) out to see if anyone was home. A few more might get sent, but Mars has limited staff and without being able to secure replacements doesn't really want to risk more than needed. Plus with an automated factory under it's thumb on earth they can just beam it designs to build, or at least build things that can build the things it wants. I wanted to avoid it looking like it's easy given we've actually lost stuff we sent up there and figure there would be similar problems.

Hah. Now that I think of it Olympus Mons extends past the martian atmosphere, so turns out to not only be a great barrier to hide under but just from laypersons perspective looks like a /great/ launch site.

I just remember the ISS taking what, about a decade to build? Would five years for Project Costellation* be feasible? Sure there is a smashed infrastructure, but now there's no red tape left you can't send a few earth movers over to shut up so you can get back to work. Ten years would probably be a safer bet. Have the colony go more or less into standby other than three month check-ins and maintenance once current projects to connect the three finish.

*Sorely tempted to just call it Project Voltron and be done with it.

Edited October 14, 2014 by Will Fawkes

[Nibb31]

Oh, alright. So this is for a book? Maybe you should have explained this to begin with.

I'm not sure what you mean by "salvageable SLS" or what sort of universe this is supposed to be in, but you're not going to launch rockets without some heavy infrastructure, high technology, and industrial capacity. You need power to produce and store cryo fuels. You need the VAB and crawler transporters to lug them to pad 39B (no, there is no way any launch infrastructure will ever exist in the Midwest, or you could even transport the rockets there. The cores are built in Louisiana and have to be transported by barge to KSC). You need the SRBs. You need to test all the valves, pumps, pyros, wiring, etc... You need functional computer guidance systems and people who can configure them for the mission. You need a skilled and trained workforce or hundreds of people to run all those systems.

If you want to describe something like pulling the Saturn V out of a museum to make it flightworthy again, it's a stupid idea. Unless of course you want to play it like Star Trek or Armaggedon and just wave stuff away with storytelling magic, in which case anything goes.

Olympus Mons might sound like a great place to launch from, but it's a really sucky place to land at. No aerobraking means that landing needs just as much delta-v as launching and you would be exposed to extreme temperatures and cosmic radiation.

I'm still not sure what it is you want to do in five years or ten years or whatever. You're not giving us enough context to understand what you really want.

Edited October 14, 2014 by Nibb31

[Will Fawkes]

Here is what I want: I am writing a book about a post humanity earth where colonies on mars sent a couple robots to earth to see why nobody's been calling. These robots have secondary orders to try securing parts to return to mars so the colonies can keep functioning. Setting aside all the ground based problems of busted infrastructure, hostile scorched earth weapons roving the earth, and random AI trying to reprogram everything to serve them, I want to know what it would take to get several hundred tons of stuff to mars.

As for the comment about SRS rockets, look above my last post, person was talking about those along with gross tonnage/lifting capacity. I know precisely squat about rocketry, or at least I am setting aside what I think I know because pretty sure a bunch of actual rocket scientists hang out here.

As for 'pulling rocket out of a museum', that had actually occored to me because supposedly the one at Kennedy only needs to be reassembled, and fueled. However even something like the falcon nine would require massive investments to get going and I expect just standing the Saturn up would be something of an achivement much less getting it in space.

Five years, or maybe a decade. Either way I want an actual timeline to sorta hang things off of to make things, if not completely realistic, 'good enough' that in a world where your toaster hops around to look the world over for a piece of bread it's believable.

You do raise a point on landing on Olympus Mons. However that is what the colonies are under. Each has an entrance set into the mountain since originally they were made by three different nations. So how do I get stuff there? Keep in mind they do have heavy construction equipment because how else are you going to dig in? There's also humanoid robots to do the actual handling (humanoid because 'we're sending tools for people to use. We have robots that have hands and general similar range of motion. Why not just teach/program them how to work this stuff?)

How workable is 'send several craft up to make the ferry vessel that all the other stuff will be put in?' Envisioning those inflatable kevlar capsule type things to maximize interior space and provide some shielding against micrometeors and the like. Thing gets in Mars orbit, then either segments drtatch and land, or... I don't know. My notes put that there would have been an orbiting station built and put around mars that might have acted as a good drop off point and ferry, but it's not there because space got canceled due to war.

Pros:

The knowledge exists as do the plans

.

No beurucratic red tape or hand wringing about budgets.

Automated factories that can be made to work night and day on bits that need building so eventually infrastructure will be put in place.

Cons:

The existing infrastructure is smashed. Other than isolated pockets of city states or the odd military site there are few gurentees outside of finding raw materials to work with.

You will need to build everything, or failing that, fix anything that is found and looks usable. Going back to the Saturn v. You would need to check over every millimeter for cracks, warps, weak spots, or any other defects to make sure you're not putting the world's biggest non-nuclear bomb on the pad.

There is no human oversight. Robots have been uplifted, but save for a few there generally won't be anyone around to give non a intuitive solutions to problems, such as reorienting craft and using the low gain antenna, or find a way around a bum Navy computer.

Edited October 15, 2014 by Will Fawkes

[Dkmdlb]

You do raise a point on landing on Olympus Mons. However that is what the colonies are under. Each has an entrance set into the mountain since originally they were made by three different nations. So how do I get stuff there? Keep in mind they do have heavy construction equipment because how else are you going to dig in? There's also humanoid robots to do the actual handling (humanoid because 'we're sending tools for people to use. We have robots that have hands and general similar range of motion. Why not just teach/program them how to work this stuff?)

You could put the landing site at the base of Olympus Mons, and then put a mass driver up the side of the mountain to launch into space. That might be fun. The low density atmosphere might make it at least conceptually possible. Any cargo launched via the mass driver would only need to do a small burn at apoapsis to circularize.

[Will Fawkes]

Why am I visualizing the world's longest potato gun angled off the side of it aimed away from the direction the planet's spinning?

[Nibb31]

How workable is 'send several craft up to make the ferry vessel that all the other stuff will be put in?' Envisioning those inflatable kevlar capsule type things to maximize interior space and provide some shielding against micrometeors and the like. Thing gets in Mars orbit, then either segments drtatch and land, or... I don't know. My notes put that there would have been an orbiting station built and put around mars that might have acted as a good drop off point and ferry, but it's not there because space got canceled due to war.

What you are describing there is a lot like NASA's Design Reference Mission for Mars. There have been several iterations of it, the latest being DRM 5.0 that involved (cancelled) Ares V launches:

Although in this case, you would only need the cargo lander. If you had all the hardware available, you could probably do the one way cargo mission with 100 tons to Mars in two SLS launches, one for the propulsion stage, the other for the spacecraft.

If you don't do aerobraking, 90% of those 100 tons would have to be propellant to perform the landing, the 10% left would be the spacecraft and you might have a few pounds of actual payload. Arrival at Mars really does require aerobraking (typically, several passes) so you would have to land at the foot of Olympus Mons, which is probably a few hundred kilometers from the summit.

Launch windows to Mars occur every 18 months and the journey is around 6 months. You would have to launch your spacecraft stage first and the propulsion stage at the last minute because of boil-off. Cryo rocket fuel can't hang around in orbit for more than a few days.

You will need to build everything, or failing that, fix anything that is found and looks usable. Going back to the Saturn v. You would need to check over every millimeter for cracks, warps, weak spots, or any other defects to make sure you're not putting the world's biggest non-nuclear bomb on the pad.

There is no human oversight. Robots have been uplifted, but save for a few there generally won't be anyone around to give non a intuitive solutions to problems, such as reorienting craft and using the low gain antenna, or find a way around a bum Navy computer.

You would need to build a factory to produce the LH2 and LOX for the rocket engines, the cryo storage tanks, and everything needed to handle rocket fuel. If your rocket uses SRBs, you are also going to need to make them. They aren't usually left around fully fueled in storage and chemicals have a shelf life.

[Will Fawkes]

So essentially to JumpStart Mars I'd have to effectively rebuild a nation just to have the supply lines and factories going on top of actual build times for equipment, testing for flaws, then the six months or so transit followed by aero breaking at the colony's doorstep.

This is a huge job. I mean I'd figured five years, but that might be just to get the things build I need before the actual mission.

The problem is how to condense that process into something interesting? I can see the milnet node I'm showing being just the biggest one left that's being aggressive, and can further cheat by stitching settlements together. Just trying to find a way to show the process without bogging down.

Maybe have a between chapters newsletter to gloss over details not relavent to the actual plotline. I'd already intended on that as a blog I can post to. Sound workable?

[Kryten]

Soyuz rockets and proton rockets are stockpiled near the launch site, so you might be able to get some of them working assuming you can restart the fuel production infrastructure (also near the launchsite). Neither will put a terribly large payload mars-ward, though.

[SciMan]

Since you mentioned "hostile scorched earth weapons roving the earth", you might be able to find a few ICBM's to use to launch smaller stuff, or just bulk cargo like fuels or small parts. Nuts, bolts, screws, wire, that kind of thing. Maybe even chemical-fueled engines, 1 at a time.

And as we all know, ICBM's are basically just shy of being orbital launch vehicles anyways, so modifications would mostly be simple stuff like swapping warheads for payloads, and re-programming the guidance systems. Delta I/II/7000 series, Titan III and Titan IV, etc. are all basically re-purposed and upgraded ICBMs, although they don't have much in common with their predecessor designs anymore, so this approach has a well know history of working.

The current ground-based ICBM that the US uses is entirely solid fueled except for the last stage, and they're in bunkers specifically designed to take a (nearly) direct hit from a nuke and still be able to launch, complete with support infrastructure.

The liquid fueled rockets would be able to get better performance, but they've been decommissioned so they're probably not available except as museum pieces.

On the other hand, the solid's are probably more likely to still be around in a recognizable or possibly even useful form after a long amount of time, anything less than a total nuclear exchange, or a limited amount of both. Then again, they're DELIBERATELY not connected to the internet, so figuring out if there's any available, or what condition they're in, would be problematic.

Regarding ressurecting "museum rockets", I'd suggest that they NOT be brought to flight ready status. Instead, use them as a pattern to copy off of, compensating for any defects that are encountered, and replacing the guidance systems with something more modern.

If more modern guidance systems aren't an option, you could probably still get away with vacuum tubes, reed relays, and core memory if the situation is really desperate.

However, a better use for that "primitive" level of electronics would be to build controls for a basic semiconductor fab. Even if there was a nuclear exchange that disabled all the solid-state electronics that you can get access to, you could still MAKE solid state electronics by recycling the "fried" silicon into material suitable for use by the semiconductor fab. Also, any solar panels that could be scavenged would be useful with a little bit of refining. Solar panels are already diodes, at least from an electrical point of view, but the quality of silicon that they use is lower than chip-grade silicon. Recycling would certainly beat refining raw beach sand into chip-grade silicon, at least at first, simply because it's so much closer to the form you need it in anyways. The stuff from the dead chips literally IS in the form you need it in, just damaged and non-functional.

Recycling also saves energy, which is sure to be scarce in a post-global-conflict age.

Speaking of energy, that's another reason the Gulf coast of Texas is a great place for this rocket-centered industry "re-boot". Easy access to large-scale petrochemical deposits, (rocket fuel) and a good location to launch rockets from. That's a winner if I ever saw one.

[Kryten]

I doubt any modern ICBM would be able to put a payload on Mars. Even R-7 required entire extra stages for planetary payloads, and it was built for far larger warheads than any today.

[SciMan]

I wasn't aiming for Mars with the ICBM's. I was aiming for them to be used to put supplies and components into LEO for assembly into a ship or payload for said ship that would then be sent to mars.

The transfer stage for the ship would be either launched separately or built on-site using components launched on the ICBMs or other available launch vehicles, with a preference for as large of a launch vehicle as available.

The decision to go for one method over another would depend on what type of engine is used, among other factors. Cryogenic-fueled transfer stages would likely need to be launched separately as described above, unless you launched the transfer stage early, then launched a fuel tanker (or just the full main fuel tank) shortly before departure.

Something like a nuclear-electric ion propulsion system could be sent up with a much wider tolerance, because their reaction mass is a compressed inert gas, however some electric propulsion methods can use hydrogen as well for better specific impulse. Now that I think of it, I would probably go with the Nuclear-electric route, and leverage the advantages of both fuel types for higher overall performance, while only slightly complicating the plumbing.

Basically, I would use something like an MPDT or VASIMR with the Trans-Martian-Injection fueled with hydrogen in drop tanks, swapping to an on-board noble gas supply for mid-course maneuvers, taking advantage of an aerocapture maneuver to enter Mars orbit, followed by using the engines to raise the orbit out of the atmosphere before cargo delivery starts. Cargo delivery would be done by a number of containers each capable of independent self-targeted re-entry, with a small hypergolic propulsion system used for the de-orbit burn, followed by a pretty standard heatshield - parachute - airbag EDL sequence. The heatshield would probably be inflatable with a rapid-setting foam that would produce an insulating char layer if the facing of the heatshield is breached. Additionally, the foam could provide the final few inches of padding that the airbags might not catch. The containers would likely be aluminum, carbon fiber, or some mix of the two, and probably end up with some rather familiar dimensions (standard cargo-ship container, heatshield on one end, chute pack and de-orbit motor on the other) The only things that the guidance system would have control over would be when the engine is fired, what direction, and when the recovery devices are deployed. It does not attempt to maneuver during re-entry, as an attempt to reduce overall system complexity and cost for what is, after all, largely a disposable system.

There's actually a fairly simple solution to moving the cargo over the surface of Mars once it gets there. A certain fraction of the containers would contain self-driving rough terrain electric cargo trucks, along with a number of wheel-sets similar to a trailer dolly, that can be attached to the exterior of the containers after they touch down via the same points that connected them to the spacecraft during the interplanetary transfer. The cargo trucks would have equipment for attaching and detaching the wheels to the containers, and would be equipped for drone control as well as being capable of automated driving as an augment and a backup to their programming. The self-driving programming would also act as an automated collision avoidance system while the drone control system is active, because the drone control system would likely be used for fine maneuvers that the autopilot couldn't otherwise handle.

[Rakaydos]

If Mars is sending out a mission to retrieve the stuff they need, dont they already have a transfer stage? They might need to refuel it, but at the very least there should be an earth return transfer stage and a earth reentry vehical.

[Will Fawkes]

Well that last does bring up a fair point. Sending a minimal resource recon team to see if anyone's at earth is one thing. There has already been talk of prepping a second mission if the first didn't send word back after landing.

However I really like the idea of 'use existing rockets as templates to send icbm's and or other smaller rockets into orbit to build a spacecraft.

Keep in mind I'm thinking large scale. Hundreds of tons of material, and most likely far more than one or even two launches could do independently. Plus with intelligent systems you're far less likely to lose stuff like we do now, or at least that's the theory.

Is there a doc that goes into more detail of the cargo truck idea?

Come to think of it how hard would it be to make fuel? I can see ion engines being somewhat readable in orbit due to the technology still existing to service/create nuclear batteries (I have no idea on the construction or if it's even possible. However if you fail an overdrive check when pushing an atomic battery. Boom. I'm guessing that's containment breech and radiation leaks fry internal components more than *mushroom cloud* but I dunno, details are light.)

[Kryten]

A 'nuclear battery' (RTG)is just a lump of radioactive material, the heat from the decay of which is used to generate electricity. There's no way you could 'overdrive' it or anything like that; the worse that could happen is material escaping.

[Will Fawkes]

Eh, it's a game mechanic I was trying to search for a way to actually explain. Hasn't come up, and with that information in mind it probably won't.

[Will Fawkes]

Possibly this deserves its own thread, but it's part of the same reason this thread exists.

What goes into making rocket fuel, and given the idea I would have to justify facilities either being tediously cared for, or rebuilt, what would be the simplistic to use that would both be able to get me into earth orbit, and would be stable enough to use for a long duration mission?