Red Fang

There is a fart joke in there, I'm sure.

In the current market, Big Dumb Boosters would never work, however new expendable launchers tend to keep being more and more cost effective with each generation, which is more or less in line with your 2nd paragraph. Wether reusable launchers will ever get to a point of displacing expendables or opening new markets by significantly lowering launch prices, remains to be seen in the upcoming decades.

Trying to approach this from another angle. I'd go for as many reusable/permanent items in lunar mission architecture, in order to turn it into a pork project that is difficult to cancel after the first successful flight. STS flew for thirty years before it got dumped, ISS is probably going to satay in LEO for 30 years... Apollo got caned early, and its specialized and expendable nature made it easier. Reusables/permanent structures make governments commit to a long-term project.

Any welder will confirm that not drying stick electrodes before welding is a bad idea, especially electrodes with cellulose coating. Hydrogen from electrode coating or rust buildup on the filler wire will easily penetrate deep into the weld and potentially parent metal at welding temperatures making the weld brittle. Not super important on some things, but very important on pressure vessels, or other items that may fail due to a poor weld and do damage to people and property.

I've totally read into your previous post something you haven't said. Sorry 'bout that. Yeah, a 100km sounding rocket or similar system might have been on the table at some point, maybe before procurement of FROG-7. Too much guesswork on my part. I'll shut up now.

Wow. I thought that the project was dead. That movie is really gonna kick off another wave of tinfoilery around here. lajoswinkler, I really doubt that there was a rocketry program as advanced the Redstone. The idea was probably discussed at the Central comity, maybe there was even a preliminary or feasibility study done. ...maybe.

Yeap. Science and engineering/machining are much easier in metric. Basically anything that requires precision or work on various scales, such as archaeology (plotting points on a skeleton while excavating a grave, with mm precision, on a site that is tens or hundreds of meters across, kilometers away from referent points on national grid, by using an EDM with an integrated GPS. Work scales: 1:10000:1000000:1000000000), ship building, ballistics...

and I think this personal observation might be relevant.* I make a lot of different things, but I mostly build medieval armour, which involves sheet metalwork, blacksmithing (making tools and some fittings) and some sewing and leather work. I find that using inches is slightly easier when you have to eyeball things, draw patterns cut straps, make buckles, fit things to people etc. Same applies to general blacksmithing and rough woodwork. To go to the extreme, If you use ruler/tape/string for measurement and eyeball Mk1 for precision imperial or similar system kicks ass. If you need calipers do do your measurements and your precision is in the sub mm range, you are better off using metric system (ie. in machining). Older systems, such as Imperial were developed to be very practical in certain applications, and units were specialized and scaled properly. Changing scales ended up being... unsystematic. Ie 12" to foot, 3 feet to yard, 2 yards to fathom, god-knows-how-many-whats to a mile. BTW, which mile? Than you add on top of that units for surface, volume, weight, etc all of which had similar differences, and similar types of specialization. Go to medieval times, and you'll see a terrible mess of physical units being based not only on physical world, but also on social climate: trade, taxes, labor, available measuring tools and very different calculating devices. Then there is the metric system, which is not particularly good on any scale, but is good enough on most scales, and is much more convenient for large-number-crunching. *I lived in a metric country all my life, and I mostly think in metric. I've had to learn and get the feel for imperial units 15 years ago, as most armouring books and forums available at the time were heavily using imperial units.

Probably thousands of tonnes + tens per colonist. To get a semi-self sufficient colony. You need to establish large/medium scale production of air, water (has to be dug up/piped up and purified), construction materials, steel, glass, plastics, food, copper, lubricants, industrial chemicals, machined products... You may need to ship in compost for a while as well. That list is just big enough so you could sustain basic consumables production and construction of buildings. If almost anything breaks down, you need to bring spare parts. Good luck setting up a ball bearing factory on Mars, or anything close to mass producing electronic components, or even making space suits. Setting up anything resembling a decent industrial capacity that can be self sustained for decades? Thousands of people... Almost anything you would need to set up industry on Mars is either Hi-tech, heavy or both. On an SF note... Even in Red Mars trilogy, which is optimistic at best, Mars stays dependent on technology shipped from Earth for a century. That is in a world where Arabs decide to get rid of Bedouins and other desert folk by moving them to Mars. With a good enough machining you can start rocketpunking your way by building some instruments (pressure gauges, valves, tachometers), electric motors etc... But you also need to reproduce industrial capacity for making all sorts of materials on Mars. IDK how much of that can be done with local chemistry. You'll be short on nitrogen and hydrogen for sure.

That would't surprise me at all. And I have nothing against speculation.

I'd try to explore a different angle on the whole export thing... To export anything from anywhere, in a broader sense, the property does not need to change physical location, only property rights have to be switched to an external entity. That way any permanent Martian society will at first be able to sell goods on Mars that can be competitive to goods shipped from Earth. I'd guess food and water (fuel, oxygen to cut down on amount of gear needed to recycle those?) would be first, then recycled/virgin metal and after that locally produced items of increasing complexity (structural elements, tools, pressure vessels, habs, rovers, electric motors...), including IP. Eventually, when (if) the martian population gets high enough (millions) Mars will be able to have a full range of technologies that are produced on Earth, and start physically exporting manufactured goods - ie. spaceships made in LMO. I'd expect this development to take centuries, at least. So, in this view, most of financial transactions would be happening on Earth, without money leaving it, while Mars-bound missions would be buying as much of the needed supplies and equipment at lower, local, Martian prices, therefore depressing costs of going to Mars and spending time there. How you start permanently populating Mars and how you go around economics of that, beats me.

That goes without saying. IMO SpaceX is trying to figure out a way to make the biggest, cheapest, long lasting, reliable, reusable system that can be made with minimal development in short amount of time, while probably leveraging NASA and private sector for mission specific and most of ground hardware. If they get one or two of those things wrong, they won't be going to Mars any time soon, and may go bust as a company. There fore concept of the BFR/MCT must be perfect, and then again all the steps in actual development, production and use have to be practically without fault for the system to work in a financially reasonable manner. I think they won't announce anything until they are 100% sure that they have nailed down rocket reusebility and I'd expect them to start actually designing the system after that. God knows how are they going to find money and justification for setting up anything more than a couple of semi-permanent research stations on Mars, but I wouldn't be surprised if they start a huge marketing/lobying campaign when they get confident that MCT/BFR can be made.

Rumor from L2 leaks implies SpaceX is contemplating even larger diameter core for BFR/MCT - 12m or 15m IIRC. We'll have to wait and see what they come up with at hte MCT/BFR announcement.

SomeGuy123 - More or less, yes. That is the idea. Though, i don't think masks could work very well. You would run into issues of sealing it properly against your face. What happens to eyes and eardrums if you manage to get a good seal? A vizor with a soft "helmet" and an adapter collar could be made very compact, probably less bulky than a gas mask. suicidejunkie - I don't know enough about rapid decompression to weigh in on utility of corset-like garments, but I know that any permanently rigid clothing is a poodle to wear, especially if you have to work against it. Anything that restricts your movement around the waist and/or restricts your breathing gets annoying to wear really fast. Nuke - Yes, we are mostly on the same page here. Let's say Newman manages to develop the BioSuit for a 2-year mars mission. That thing will have to endure thousands of hours of EVA in a dusty abrasive environment, so it will have to be though as @#$ck. Sacrificing some durability so you could wear in situations when combat is imminent (for hours, days or months?) in generally much less hostile environment, should not be that difficult. If it can be made reasonably comfortable, it could be worn for prolonged times. The question remains: how comfortable can it be made in the time-frame we reach conditions int the OP?

Super Guppy Airbus Beluga You can find decent encyclopedic info on most almost any aircraft on Wikipedia.

When you say big ship, In terms of size, I am thinking ISS, with a larger crew of up to 10-12 people. 1st layer of damage control: seal your compartment. Each compartment can be sealed, and has independent life support for several hours/days. It contains several pressure suits with several hours of life support. 2nd layer od DC is to get to a refuge. Each crew bunk can be sealed and has several hours of life support, and contains a pressure suit. 3rd layer of DC is to get into a pressure suit and evacuate/fix damage if you were not in the suit before hull breach. Pressure suits are are made to be donned and doffed in a pressurized environment, they should allow enough freedom of movement to operate basic ship functions, move through the ship and perform minimal repairs. Suit autonomy of several hours should not be a problem. (Chest-mounted diving re-breathers regularly have 3h+ scrubber and oxygen supply @ ~6m depth.) Sokol suit is about 10kg and a pack with a decent battery/O2/CO2 can probably be under 10kg, detachable and small in size. If you are flying in interplanetary/stellar combat craft or such, I would wager that you can make a good version of one-size-fits-all version of Sokol, with better ergonomics, mobility and bring its weight down by several kg. Specifically for combat ships I'd pursue a uniform for which you'd use a mechanical counter-pressure suit that is self-tightening on command. Such command could be issued by a pressure switch, manual switch, or by putting on a helmet. External packs with life support could be distributed all around the ship, while a small life support pack with 15-30min of air supply and CO2 scrubbing capacity could be carried around at all times, somewhere on your body or as an integral part of your helmet. Judging by info available on MIT BioSuit, we may be years to decades away from a working model, and even further away from an advanced model described in this paragraph. However, we are much further away from developing manned warships/torchships etc. so suit technology should not be a problem.

I'd like to see international effort to test some nuclear golf concepts on asteroids. It may prove to be a viable option, for some, or most intercepts. Depending on number of shots, development prices may skyrocket like a Sprinting Gazelle, especially if it turns out development of new warheads is needed. Nuking an asteroid to give it several cm/s or m/s to change its orbit enough to miss Earth would answer several questions. - Is it feasible at to use nukes to disturb asteroid orbits? - How do different asteroids react to different nukes? (solid iron, solid rock, rubble piles, comets... vs. regular/neutron/shaped charges) - What are optimal parameters (ie, standoff distance, yield, warhead type) for redirecting different asteroids? - What are ultimate limitations of nuke-the-asteroid method in regards of object size, composition, mass, orbit, warning time etc... And an additional, programmatic questions: - How to integrate warhead, kill vehicle and launch vehicle in a way that is low-cost, storable long term, and quick to launch (hours/days). - How many different rocket types would you need to have on-hand? (Would a heavy ICBM derived vehicle do for most cases? ...like Dnepr-1. Would you need capability to quickly integrate, fuel and launch a pulse unit on a heavy/medium launcher such as DeltaIV heavy, Proton, Ariane 5 / Soyuz, Falcon 9 ?) - How would you store pulse units to make them safe from theft and unauthorized access? Now that I have listed all those things, I think this would not be cheap. Lets say 5-10 test-shots, with several test-launches... developing 1-3 standard delivery vehicles in different weight classes. Potential development of new warheads. In the end, buying a stand-by force of some 20 ( ? ) launchers and delivery vehicles, new storage facilities, refurbishing some dozen ICBM silos, paying for storing those things for decades... Yeah, this goes well into tens of $ billions easily. At best, I can imagine someone, somewhere having a paper project on how to crash-launch a nuke to intercept an asteroid...

That landing was magnificently uneventful. Great job SpaceX!

So you are saying that the cable for a working, realistic, "we can start making it now" space lift cable weights on the order of 100 tons? Am I reading this right?

I wouldn't unless I really have to. That said, if you need a lot of dV and don't have an atmosphere to fight, you can get 0.5 mass ratio for a NTR 6500m/s rocket stage. That should be more than enough for propulsive Mars landing and takeoff without refueling (propellant issues aside). Using NTR has the benefit of spewing very little fallout in the form of hot particles, so it would take only a couple of days, (maybe even hours if you don't have to stick around the lander for long!!! ) to be safe to leave the lander. A couple of tons of water around the crew compartment should provide sufficient shielding against gamma particles from the landing fallout, while the propellant itself and a shadow shield should protect you from the engine. Atomic rockets has a detailed article on a more powerful NSWR called "Polaris". Quick calculation says that you can make a 100t SSTO by strapping 3x Timberwind75 NTRs using 70t of LH, with a payload in the range of 10-15t provided you are prepared to put up with some fallout. Thermal protection for atmospheric landings and long spool-up periods for NTRs would probably render this design non-deployable from orbit. That made thinking of what to do on a planet with an atmosphere that provides significant lift and drag, ie. enables flying. If you manufacture your spacecrafts off-world, you might be able to land an empty lander after it discards heat shield, top it up with propellant and launch in as many stages as you need. That seems quite expendable. Using nukes, it might be possible to make a reusable one, which would require a runway, a base and a dedicated launch aircraft. My math just about adds up, but it's back-of-the-napkin calculation...

My question, as an armourer, is: ... was stopping them to get the shape of the body-can semi ergonomic on these prototypes? People have worked out ergonomics of rigid suits way before Coulomb established scientific principles of engineering. With 60s technology it should not have been to hard to reshape that cylinder into something less bulky. For Jeb's sake, the suits actually used for moonwalks were orders of magnitude better designed. Why make a such a half ass effort in the early stage of design?

That is A LOT of radiating heat coming of burning fuel particles. I wouldn't be surprised if the smoke coming of the hill next to the booster was actually water vapor being pushed out of the ground by the heat, in addition to dust being picked up by the air current.

Nice of you t o start this topic, as I have been reviewing Zubrin's speeches for the past couple of days. Too bad I have not been able to a hold of his books by now. I'll see to remedy that asap. Meanwhile, here are my opinions on Mars Direct: Mars Direct sounds as a solid plan, better than most, semi direct more so, regarding safety. There are some hurdles along the way. 1. Unfortunately, it seems it is to late for quick and dirty development of an STS derived vehicle, suc as Jupiter of the DIRECT proposal, so we are probably stuck with SLS and/or something new, and hopefully cheaper. Up to two or three docking launches might be acceptable: one for Earth departure stage, one for trans-Martian habitat and Mars orbit insertion stage and the third just for the crew. With a bigger launch vehicle, you might get all that launched on one really superheavy launch vehicle such as an SLS BlockII was planed.. (not sure if they still have Block II in the foreseeable future). 2. Sabateur converter has not been tested in Martian atmosphere. It should require a dedicated robotic mission to be done. The part I am most concerned about is supplying enough empty tanks to the converter as well as landing a large volume of liquid hydrogen without rupturing the tank. ~8 tons or about 85 cubic meters! Alternative is an automated system for extracting water from Mars surface and supplying it to the converter which will extract H2 and O2 from it. 3. The mission design calls for a 50-100 kW reactor that should work in Martian atmosphere. AFAIK we do not have a working design for such a machine. OTOH, even with a 25kWe reactor on Mars the mission should be doable, while a smaller design, such as a modified Topaz II with a decent turbine or a Stirling engine might work for a prototype. I do not know enough thermodynamics to judge whether cooling at such low atmospheric pressure should pose a significant problem. 4. The heaviest payload that we have landed on Mars is ~1 ton. How do we land a 20t habitat and a huge Mars Return Vehicle in the same weight class but with a huge volume and height? There might be some significant challenges to developing a heat shield and parachutes for that. There might be some merit in propulsive landing. 5. Radiation. That is a big scarecrow, or as Zubrin would say: "a dragon to be slayed". We do not need much more than several long term missions beyond the Van Allen belts to prove and IMPROVE our knowledge about radiation shielding both from cosmic rays and solar flares. 6. Life support. We need high efficiency to keep the mission weight down. That is especially important for O2 and H2O. Food should not be an issue as it is routinely packed to high nutrition/weight ratio. 7. Doublecheck everything to see if that fits into mass limits of a 20-30ton landing habitat and MAV. 8. Methane engines. No, seriously, liquid methane engines have never been in serial production, so if you want them to be reliable, Other challenges include selection and development of rovers, making a choice of Habitat+Rover or just a bigass rover, (re)development of NERVas, choice of fuel for EDS depending on the mission architecture (any docking/orbital assembly operation will most certainly be better done with hypergorlics, and a single launch mission would be doable with hydrolox. There is a big mass penalty for hypergorlics. ); building a global survey and navigation network, testing a tether system for artificial gravity to confirm mass and reliability etc. Oh, and one more problem: wee need vehicles with long term storage capability in space. To sum it up, you need several precursor missions: 1 or 2 - sabateur converter, tanks and reactor test on mars. 2 - Mars landing mission with heavy, bulky payloads Methane engine testing and development, HLV, and a small station in high Earth orbit with several crews staying up for 6-24 months at a time. I am certain that all that should be doable within a decade provided sufficient motivation and financing. HLV might be a problem that could only be solved in a CCDEV way. The thing that scares me if the Mars Direct program gets of the ground is becoming to expensive not to be shutting down the program before committing to colonization, the way Apollo got cut.

I didn't say they don't work.

It is basically a benzodiazepine. I hate those things and use them very, very rarely. 2-3 times a year, at most, and i take the minimal dose that would get the job done. They ARE addictive and they do mess up your cognitive functions to a certain extent. I just love my brain too much to use them as much as i should. OTOH, they have a nice effect of making people not give a frack. Search wiki for benzos, and it should scare you enough to actually follow doctor's advice and use them only when there is no other option.