Nibb31

Orion is MUCH more expensive than the Commercial Crew vehicles. It is not reusable, and each vehicle costs approximately $500 million. It can only be launched on SLS, which also costs $500 million, because no other rocket is man-rated. That is why NASA can only afford to launch 0.5 mission per year. CST-100 and Dragon are going to cost NASA around $150 to $200 million for each launch. Centaur isn't man-rated. Delta IV Heavy was big enough to launch Orion EFT-1 unmanned, but it also isn't man-rated, so it can't be used for manned flights either. Atlas V will be man rated for CST-100, but it's not big enough to launch an Orion with any sort of mission module. Falcon Heavy could do the job. If you use Orion for LEO, it's also a lot heavier than it needs to be. It's much heavier and larger than Dragon. The trunk is unpressurized volume, but it is limited by mass. It would need to be a very small lander. But really, what is the mission profile you are looking to fulfill here? It seems like you are starting with the hardware and then trying to find something to do with it. What you need is a mission, and then figure out a way to use what you have, or design what you need, to do that mission. Orion is designed to support an active crew of 4 for 21 days. It can be powered down and stay quiescent for 6 months attached to another vehicle. By itself, it's enough to do a circumlunar or EML flight or a trip to a NEO.

I found Elon's quote here: http://www.spaceflightnow.com/falcon9/009/140430firststage/#.VJG8yHsV9Zg Well, I guess I disagree with Elon. If the first stage is 70% of the launch price, then that's over $40 million just for a first stage booster. The infrastructure, R&D, administration, transportation, logistics, facilities, workforce, mission control, etc... plus the upperstage and the payload integration are only one third of the launch? Nope, sorry, I don't buy those numbers.

Artificial gravity is not necessary for any mission profile in the foreseeable future.

Orion is too expensive to waste on launching it to LEO, and sticking an Orbital module on the front is a no go because of the LAS. For LEO, I'd rather see a Dragon with a hab module in the trunk. It could be something inflatable, like BEAM, but with an IDS docking port instead of a CBM. However, if you really want to use Cygnus, there's nothing stopping you from docking with one on orbit or carrying up a Cygnus-based hab module in the cargo area of the SLS, although I would go with something closer to an MPLM than Cygnus. Something like this would extend Orion's 21-day limit for a circumlunar or EML flight, but there really isn't much point. Orion can handle 21 days, which is ample time to do whatever needs doing in lunar orbit without landing, and this isn't suitable for a really lond duration flight like a Mars or Venus flyby.

Even Musk can only colonize Mars if he finds people willing to buy tickets to colonize Mars. Which is already a stretch. Only millionaires will be able to afford a ticket, and millionaires don't typically become candidates for colonization. And that is another stretch. And well, a lunar lander is not the same as a Mars lander.

First of all, launch cost is not launch price. If SpaceX is selling launches at $61 million, I certainly hope it doesn't cost them that. Musk is an entrepreneur, so he should be making a decent margin even with that price. Next, I'd like to find the actual quote for that "75%" number. 75% of the cost of the rocket is not 75% of the cost of a launch, because the actual rocket hardware is only a small part of the operational cost of launching a rocket. Then we'd need to know what that 75% represents. Does it include manufacturing costs, material, development costs, propellant costs, testing, transportation, handling, stacking... ? If you reuse your first stage, you don't save all of those costs. You still need to pay for the development, the propellant, the transportation, handling, storage, integration, tooling and fixtures, etc... You still need to pay a few hundred workers to do all those jobs. You do lay off some of the manufacturing workforce. But much of the manufacturing cost is fixed: facilities, maintenance, administration, infrastructure, tooling, fixtures. This means that if SpaceX reuses each first stage 10 times, they need to build 10 times less first stages. Instead of producing 400 Merlin engines every year (which is what their factory is scaled to produce), they only make 40. This all means that the unit cost of each first stage increases significantly, in addition to the extra hardware (structural reinforcements, grid fins, legs, avionics) that adds to the cost of the reusable stage. In the end, the only actual saving might be the cost of the material and some of the workforce that they use to build the rocket. They definitely don't save 75% on each launch. Optimistically, they might save 50% on the cost of each rocket. If the actual rocket hardware represents 20% of the launch price, then reusability cuts a whopping 10% reduction in launch prices for customers, which in turn is only a fraction of the total cost of operating a satellite.

Remember that composite tanks are more expensive. Using them for disposable tankage might improve performance, but it also increases manufacturing cost. In some cases, it might also impact operational cost (maintenance, repairs) and safety or reliability, because those materials are less well known and trusted. Increased risk means higher insurance costs, which again negatively impacts the launch price. Composite tanks are not a new idea. Aerospace companies have known about them for decades. They don't make rockets out of aluminium because they are stupid. The reason they use the materials they use is because they offer the best combination of various factors. In most cases, it will be cheaper to increase performance through other means with trusted technology: bigger engines, bigger tanks. Engineering is about finding compromises between a multitude of requirements: cost, performance, flexibility, reliability, safety, logistics, schedule, infrastructure, etc... Which is why my first answer to the OP's question "How would you improve current launch vehicles?", was "Improve how?". Because improving one parameter is always going to negatively affect a whole bunch of other parameters.

And the point flew over your head. My point was that the smart people who tend to invent new stuff also tend to get an education and find themselves working in an industry that pays for smart people like them to invent new stuff. They tend to publish papers and attend conferences where they interact with their peers, not internet forums. It used to be possible for someone to invent a new groundbreaking technology in his garage (or in his cave). That is not really the case any more, especially when you are dealing with vast amounts of energy that require a heavy infrastructure to work with, and a technology field that is too complex for any single person to be an expert in all aspects of it. The low-hanging fruit have mostly been picked by now.

Frizzank, The Gemini pod is broken in 4.99. When you put it on the pad, you don't get the crew photos or the staging sequence. I traced it down to the Spaces/FASAGeminiInt2/internal.cfg that had name = FASA_Apollo_CM_Int in it. I changed it to name = FASAGeminiInt2 and the problem was solved.

I'll just add that there is a multi-billion dollar industry based around space flight. Some of the smartest people in the world are employed by some of the most capable institutions and corporations in the world to design rockets. These organizations have been continuously innovating and improving technology for decades. Neophytes on an internet forum are not going to come up with a breakthrough technology. If you've had this crazy idea that might well work, let me tell you: chances are that someone else has already had that crazy idea and if nobody is using that crazy idea, then it's probably for a good reason. Aerospace engineers and scientists aren't idiots. Believe me, if there was an easy and cheap way to get stuff into orbit, we would be using it by now.

All the commercial crew vehicles use a variant of the IDS adapter. SpaceX is only going to fly something that they get paid to fly. If NASA does an RFP for lunar hardware, they'll bid.

PR is secondary. NASA isn't in the entertainment business. Flying to an asteroid or a circumlunar flight has very little scientific or technological value. They are just stunts that don't demonstrate or validate any new technology. They are just poor attempts at self-justifying Orion. The truth is, Orion was designed to fly to the Moon as part of the Constellation. Constellation was cancelled, but Orion wasn't, and now that NASA has Orion, and isn't going to the Moon, they are trying to shoehorn it into missions that it wasn't designed for. Mars is one them. So is the asteroid mission. If you want to visit Mars, Orion isn't particularly necessary. If you want to study an asteroid, Orion isn't the best way to do it. If NASA or Congress or the POTUS want to use Orion, then they need to stick a lander on top of that SLS and return to the Moon.

Improve how ? There are very little gains to be obtained in chemical rocketry. It's going to be increasingly hard to squeeze more efficiency out of chemical engines. If you want to increase performance, you would a higher energy density, which means either fantasy unobtanium or nuclear. Nuclear is a no go for plenty of reasons. If you want to reduce costs, then there are no other choices than to increase demand. A larger market allows economies of scale, lower unit costs, and reusability. A small market increases infrastructure and manpower costs. There is no way around that. The problem is that there are no viable business models that lead to increasing demand for space access. There are a couple of dubious ideas floating around, but none are proven. In the end, you will always need vast amounts of energy to accelerate a payload from 0 to 27000km/h, and the energy density of chemicals isn't going to change. Handling vast amounts of energy will always be expensive and complicated. That is why, as long as energy is at a premium, and as long as it's dangerous to handle huge energy sources, spaceflight is always going to be a niche business.

$50 million was the 2013 price. The current listed launch price is $61 million: http://www.spacex.com/about/capabilities Yes SpaceX fanboys, the price has gone up! Inflation, infrastructure, marketing and a full flight manifest are to blame. If reusing the first stage scrapes more than 15% off the listed price, I'll be impressed.

10 years from now, Space X will have some experience with first stage reusability. With a bit of luck, they might have managed to cut prices down to $50 million for an unmanned LEO launch, which is impressive compared to the $150 million it was a couple of years ago. Commercial crew will be winding down with the EOL of the ISS. They might be able to offer tourist tickets for $15 million per seat, but I don't think that price is low enough to maintain a sustainable business model. Constellations will go up on a single rocket. You can launch 200 sats in 10 launches. It will keep lunch providers busy for a while, and it might compensate for the saturation of the GEO market, but it won't generate volumes to make an frequent-flyer SSTO sustainable. Bigelow had no customers 10 years ago and they have no customers now. I don't see why they would have more customers in 10 years. The issue with the launch market is not really a matter of price. It's just that demand is not there. Those who need into space are willing to pay the price for it. Those who don't need it won't buy it, however low the price is. Cut prices in half, or even divide them by 10, it won't change the game.

Skylon is a hypothetical design. It might really well on paper, with highly optimistic margins and fantasy funding, but it is unlikely to ever fly, for reasons that have been explained in a dozen threads in this forum already. FTFY. Partially reusable. It was an awe-inspiring machine, but it was also a fundamentally flawed design that didn't make any sense economically. Theoretical rockets are always better than operational rockets on paper. Reuse isn't always economical. There are many sectors where disposable is more economical than reusable. It all depends on the volume. A reusable launcher isn't necessarily more economical than an expendable one. Experience proves that aerospace projects ALWAYS end up at least slightly overweight, slight underpowered, and hugely overbudget. The truth is that nobody has the faintest idea how Skylon will perform exactly, what its margins will be, and what its operating costs are going to be. It's an investment. And an investment calls for a return on investment. A fully-reusable launcher is only viable if you fly it frequently. There simply isn't a market to support frequent orbital flights. It's not a matter of interest, it's a matter of return on investment. At the current flight rates, vertical launch rockets simply offer a better return on investment. Quite possibly. But is it NASA's role to spend billions of taxpayer's money on developing new transportation technology when there is no market to back it up?

No. The Delta IV Heavy is the largest rocket in the US inventory, yet it could only send Orion into a high orbit with an apogee of 5900 km. The Moon is at distance of 384000 km. The only rocket that can send Orion to the Moon will be SLS. There are no plans to ever fly Orion on Delta IV again because Delta IV isn't man rated. Orion has no life-support systems yet, so a manned flight is out of question until Orion is finished. SLS will be perfectly capable of sending an Orion around the Moon. In fact, its first flight (EM-1) is likely to be an unmanned circumlunar flight, but you'll have to wait until 2019. The second flight (EM-2) will likely be a manned circumlunar flight around 2021. They wanted to do the asteroid retrieval mission for EM-2, but it's a bit risky for a first manned flight. There are no further missions planned for Orion at this time. Only 2 service modules have been ordered from ESA and nobody is working on mission modules or landers, so it really can't do anything else than fly around the Moon. If we started working on a Moon lander today (which isn't going to happen), it would take at least 10 years. That means that Orion and SLS will be sitting around gathering dust for years with no flights, which isn't sustainable budget-wise. It will probably be cancelled before any mission modules are ever built.

Not really. The cost of sending out ships to recover the spent SRBs, repairing, refurbishing, and checking them, was higher than making new steel casings from scratch. They were just steel tubes. The expensive parts of the SRBs (skirts, parachutes, cones) weren't reused.

Typically the default page for a directory is index.html or index.htm. If you want it to be something different, you can change that in the web server configuration file. I think you can also set the name of the index page in an .htaccess file that you put in the directory.

Just use Google Now.

Yes, the numbers compute. My question is with the noticeable inner-ear effects claim. I don't think we have any experience of a 224m centrifuge operating at 2 rpm in microgravity (even on Earth, I don't know if there are any experimental centrifuges that big)

Typically, solar panels have mechanical deployment mechanisms, which makes them more failure-prone (that was a lesson learnt from Skylab). They also need to point in direction of the sun, which means either pointing the craft in the proper direction (like Soyuz), which would have been a major annoyance for a vehicle that was supposed to do all sorts of delivery, construction and maintenance jobs, or you need even more mechanical failure points with rotating joints and hinges. Having them deploy out of the payload bay would have interefered with mission equipment deployment. Having them deploy out of side hatches meant more openings in the heatshield and yet more mechanical failure points. On the other hand, fuel cells were simpler, lighter, and also provided drinking water. Why bother with solar panels?

Again, SSTOs or spaceplanes ? I just explained to you that SSTO is less efficient than MSTO because it has a smaller payload fraction. A conventional MSTO rocket typically has a payload fraction of 0.5%. This means that you need a 1000 ton rocket to launch a 5 ton payload (0.5% if the total weight of the rocket). An SSTO rocket typically has a much lower payload fraction because it is less efficient. It is less efficient because it has to carry all that heavy tankage and those high-thrust first stage engines to orbit. The payload fraction is eaten up by that extra weight and ends up either negative (it can't reach orbit) or so insignificant that it's useless (0.005% of your 1000-ton rocket) So how is a rocket that can't put a payload into orbit more cost-efficient than a rocket that can ?

[Citation needed]

We don't have single-stage-to-orbit launchers because they suck at launching stuff. Dropping stages along the way makes your vehicle lighter and therefore much more efficient. SSTO is easy as long as you don't care about the payload. The ancient Mercury-Atlas was nearly an SSTO (it only dropped its engines on the way up), and the Titan first stage or the Saturn 1B with nothing on top had enough dV to reach orbit in a single stage too, although it was never tested because they weren't throttlable or restartable and because it was pointless. With modern technology, it would be easy to make an expendable SSTO launcher with a tiny payload. The thing is, designing an SSTO launcher with a sucky payload is pointless when you can launch a multi-stage rocket with a significant payload. PS. And yes, I know you weren't really asking about "SSTO" but about "reusable spaceplanes". So please use the term "reusable spaceplane" when talking about reusable spaceplanes and not "SSTO", which is a flight profile, not a type of vehicle. It's quite possible to envision SSTO rockets, reusable rockets, multi-stage spaceplanes, and all sorts of other combinations... To summarize: - The reason we don't have SSTOs is because MSTOs are much more efficient. - The reason we don't have spaceplanes is because they are much heavier than rockets because you need to carry all that plane stuff in addition to all your rocket stuff. Therefore you can't carry any payload unless you invent some new breakthrough material and breakthrough engines. - The reason we don't have reusable launchers is because the demand for orbital launches doesn't allow launch rates frequent enough to make them economically viable.