Nibb31

An aerospikes is a nozzle design. Their main advantage is that they have the same efficiency at sea-level as in vacuum, which makes them good for SSTO applications. However, because there are no operational SSTO rockets, they have never been used. Aerospikes are usually less efficient that bell nozzles that are each taylored for a specific altitude range, which is actually good because you're staging anyway.

The EELV program was initiated because the Titan and Atlas launches were way too expensive: Atlas and Delta launches costs around $100 to $150 million. Falcon is somewhere between 60 and 100 million. I don't have the figures for Ariane, but Ariane 5 is much cheaper than Ariane 4.

There is more offer than demand. The current launch market is saturated. Global launch capability is in overcapacity. To the point where some launch providers are having trouble remaining competitive. You can't have dozens of carts going up and dozens going down at the same time on the same tether. The space elevator is a theoretical construct. Nobody knows the exact operational constraints because we don't know the weight, strength, or cost specifications of materials that don't exist yet.

Planetary Resources' business model is to develop flashy Powerpoint presentations to attract venture capital investors and government grants to keep the company afloat. Sometimes you get a mockup or a trade study, but the main business objective of these companies is keep a paycheck coming in for their CEOs. This is not uncommon in the "New Space" sector: Golden Spike, Mars One, Excalibur Almaz, RocketPlane Kistler, JP Aerospace and yes, Skylon all fall into the same category for me. Wake me up when any of these companies sends up a real spacecraft and has a sustainable business model. Common spacecraft busses have been around since the 70's. They're nothing new. They are mostly for GEO comsats, which usually share the same requirements. There have been lots of plans for LEO constellations, but none of them have been successful (Iridium comes to mind...). Will it be cheaper than land-based LTE towers? How big is the actual market in areas that don't have access to LTE? It will be interesting if Google succeeds, but they would need what, 20 to 30 launches, to build their constellation? That's a nice contract for any launch provider, but that's doesn't make a business model. Or the dozens of other projects that they have started and abandoned: Orkut, Checkout, Wave, Reader, Latitude, Buzz ...and Motorola! Google has a habit of trying lots of different things and abandoning them half way through. They have lots of cash to spend, so it's not stupid to spend it on new ideas to see what sticks. But they accept the fact that some of them will fail.

Technological advances are incremental. You experiment new solutions by improving things that have been done before. You build prototypes and technology demonstrators to test each individual part of the system. When you try to include too many new technologies into a single vehicle, which are all essential, you always end up with a final result that doesn't meet expectations. Examples: Space Shuttle, X-33... SpaceX is a more realistic contender, as it is incrementally improving on existing technology. They don't intend to leap from zero to a fully reusable MCT in one go. A 50% reduction in launch costs compared to their Atlas or Delta competition is possible (that is $50 million instead of $100 million), but it will be more through lean management and innovative business processes than through reusability and it will not be enough to open up asteroid mining or space tourism markets. ESA is not funding Skylon. They have funded trade studies for a few thousand dollars. ESA is having trouble gathering enough money to design Ariane 6, which from the latest news is simply going to be an evolution of Ariane 5. ESA gets its money from governments of member states. In the current economical, no European country is going to suddenly increase ESA funding to build Skylon. That is not going to happen. Rockets are launched from space centers. You need to either build a huge runway at Guyana Space Center or to build a huge Hydrogen production and storage plant at a major airport in the UK. Do you have any idea how much time and effort goes into these sorts of things? There are environmental impact studies, urbanisation studies. There are expropriations and administrative processes that need to be followed. Yes, it does typically take 20 years to build an airport anywhere in Europe. No. We do incremental improvements. SpaceX is on the right track, although they have been promising a lot and they now need to actually deliver. Skylon is just a handful of old dreamers working in a shed. ESA is paying for preliminary trade studies. It's a drop of water compared to the money needed to actually develop any of the technology. It is a challenge. Especially if you want rapid turnaround and several flights per day. So where are your own cost and profit estimates? Where are your examples of similar business models? You started a discussion about economics, but I haven't seen a single number, estimation, or comparison with real-world equivalent industries. Only handwaving tough engineering and political problems away as "easy" or "high school level" or claiming that others are "wrong" without any argumentation.

You mean to make a plane bigger than the An-225? There are practical operational limits. The biggest one is runway length, width, and strength. Width is important to prevent the engines from ingesting dirt and grass. Strength is important because landing such a heavy airplane imposes huge constraints on the structure of the tarmac as well as the taxiways. There are other practical limits, such as refueling capacity, passenger catering (except for cargo planes, obviously), and cargo handling infrastructure. The infrastructure costs related with upgrading airports negate any benefit you get from having a greater payload capacity. The A380 was already a bit of a stretch and required some airports to make some very expensive adaptations. If Stratolaunch succeeds in its plans, its carrier aircraft will be the biggest plane in the world. Whether it makes sense commercially is very much up to debate...

They still are. The 5th and last prototype had its maiden flight last week. The first deliveries will be to Qatar Airways at the end of the year. A beautiful plane.

I saw it land a couple of times at Toulouse airport as part of the A380 program a few years back. They were using it test to the durability of the runway and taxiways before the A380 and maybe to bring in some big parts before the special convoy route was built. Antonov 124s are much more common. My favorite is still the A300-600ST Beluga that flies in front of my window several times a day.

That is "offer" not "demand". Bigelow has been trying to scrape up enough demand to justify his offer for years now.

Now, with Skylon out of the way, as well as the hypothesis of 90% launch cost reduction, let's move on. How do you know it doesn't need testing? Replace "testing" with "maintenance". Everything needs maintenance. Things that are pushed to hypersonic speed, exposed to vacuum, go through physical stress, and reenter at high temperatures need more maintenance than things that don't. Elon Musk has stated that he hopes to reuse his 1st stage boosters up to 10 times. Rocket stages have a limited number of tanking cycles. They go through extreme thermal and physical loads. You are always going to need to perform some maintenance, cleaning, inspection, and testing on each stage before reusing it. We are not talking about cars or airplanes here. Please explain why you wouldn't need them. And if you are going to find new markets, you are going to need LOTS of marketing and sales people. Do you think seriously think launch providers or airlines don't need marketing departments? How do you run a business without any administrative overhead? How do you get the rocket and payload ready for launch without integrating and stacking the reusable stages? Quote please. That's ridiculous because it implies that for a projected SpaceX launch price at $50 million, each first stage booster alone costs over $35 million dollars! In reality, we don't have the actual numbers of how much an individual SpaceX launch currently costs (hint: it is way higher than the "projected" price of $50 million) because private contracts are confidential or launch slots are purchased in bulk. The actors in this market only distill incomplete information as they seem fit. When Musk talks about reducing by X%, does he mean compared to current ULA prices? current SpaceX prices? Future SpaceX prices? Does he mean with just one reuse? 10 reuses? First stage only? Manned or unmanned? We simply don't know, so we can't take anything for granted. Your numbers are unsubstantiated. I have provided examples and comparisons for mine. Yours are just wishful thinking.

Alright. First of all Skylon. Here's a mashup of my previous arguments about it. Skylon's engine, airframe, TPS, and pretty much every other technology are unproven. In theory, with some very optimistic margins, it should be capable of SSTO with a payload, but that's only theory. In practice, not a single large aerospace projects has gone without cost, weight, or schedule overruns. Attempting to implement so many new ideas in a single project that relies on each one of them working flawlessly only multiplies the chances of that project to fail. Especially when you are a small organization with limited resources. - Skylon's fuselage structure and outer skin is unique but it also doesn't use conventional construction techniques. Airliner fuselages are typically cylinders that are bolted together. The same tooling and transport jigs are used for all of the sections. It uses all sorts of exotic materials that nobody has much experience with. So even then manufacturing techniques and tooling need to be developed from scratch. It took years for Boeing to industrialize the 787 carbon-fibre fuselage, and it's still much more conventional than Skylon. - Skylon's TPS uses a new mix of superthin carbon-ceramic material that has never been tested. On paper, this isn't enough, so it also uses active cooling by vaporizing LH2 on the wing edges. Again, this has never been done before and is purely theoretical. Nobody knows how feasible these new techniques are in the real-world or what happens if the vaporization system fails or underperforms. Until someone flies a tech demonstrator through reentry, it's a no-go. Reentry demonstrators are expensive things to do. For example, ESA's IXV program took 5 years and 150 million to design, and it is just a subscale model that will fly on a Vega rocket. - And of course, there is SABRE, on which the whole idea relies and that hasn't even been made into a subscale test bench demonstrator yet. They are decades away from making a flight-capable engine, let alone achieving the reliability and serviceability requirements that you need for flight operations. Yes, they have a prototype pre-cooler, which was the trickiest part to get working. Yet, how durable is it and how close is it a flight-ready component? Another comparison: It takes $1 billion and 10 years for P&W or GE to develop civilian jet engine. High performance military engines are typically more expensive. Because none of the technology has been proven, nobody can tell what the actual capabilities will be, or even if it will be viable at all, because nobody has any experience in operating SABRE engines, in constructing an airframe like Skylon's, in commercially operating a reusable SSTO spaceplane, or even if the TPS is capable of withstanding the reentry constraints. We don't know how reliable it can be, what the service intervals or operation constraints will be, how much payload it can carry, how much it will cost to buy and fly, or if it can be economically viable. In the end, if the SABRE engines slightly underperform, or if the airframe ends up slightly heavier than planned, or if the TPS needs to be slightly thicker, then there goes your payload ratio and the viability of the project. That is a huge risk. Skylon is bigger than an Airbus A380. Just to build a conventional heavy airliner requires a major airport with a reinforced runway, a production facility the size of a small city, and a supply chain involving hundreds of subcontractors. It took Boeing $32 billion and 10 years to develop the 787, which is just an airliner with fairly mature and well-understood technology, except for the carbon-fiber body. EADS spent $25 billion dollars to develop the A400M, which is just a conventional turboprop cargo plane. These are companies that have supply chains, armies of engineers, and they are working with reliable and proven technology. It takes years just to design stupid things like the landing gear or engine mounts... It takes more years to set up the logistics, to build or adapt a factory, to negociate supplier contracts, and so on. They need factories, test facilities, upgraded airport infrastructures, transportation, cranes, tooling... There are zero subcontractors who have any experience building something like a SABRE engine, a unique carbon composite airframe larger than an A380, a unique TPS, the avionics... Just developing the tooling, the jigs, the test fixtures, and the software is going to take years. Heck, it even takes years just to hire the workforce that you need to do all those things. Skylon is bigger and heavier than an Airbus A380. There's only a limited number of airports in Europe that have the reinforced runways that could handle it plus manufacturing facilities for large aircraft. The Airbus plants in Hamburg or Toulouse, and maybe a couple of others. So if Airbus is not a partner, and not willing to move their current production lines to make place for Skylon (airliners are much more profitable) they need to build a new factory and/or a new airport. Skylon runs on LH2. It need lots of it if you want a fast turnaround. There are zero airports that have massive LH2 production or storage facilities nearby. So they also need to build that, which might not be possible at any of the existing manufacturing sites at all due to all sorts of environmental, industrial or political problems. Now, things like factories, airports, supply chains, or hydrogen plants don't get built over night. They require years of paperwork, planning, paperwork, money, paperwork, construction, more paperwork, and political lobbying at a very high scale. You're going to need a strong political support to get such a project off the ground, so you are going to have to convince local, national, and EU parliamentaries and government officials. This alone is a huge effort that is going to cost millions. Those are only some of the problems that they have to solve. There is no way a small R&D company can pull off such a large project. Even if there was a market for it, even if it was technically viable, and even if ESA, Airbus, and several European governments were on board, there's no way Skylon can fly any time soon. And that's an awful lot of "ifs". Yet REL estimates that Skylon will only cost $12 billion, and that each unit will be cheaper than a good old Airbus A330, despite everything in Skylon being new, unconventional, and made of exotic new materials, and despite the production numbers being much lower than those of a typical airliner. The cost estimates are simply not realistic, and therefore neither is their business model. Compared to the programs above, with all the groundbreaking technology and materials involved, I can't see it costing less than $30 billion to develop. If they optimistically find customers for 50 vehicles, it can't have a price tag of less than $1 billion per vehicle. Now, to cover the cost of a $1 billion dollar reusable spacecraft over a 10 year period, at SpaceX projected prices (~$50 million), if the cost of the vehicle is 50% of the operational cost (which is optimistic), you are going to need to fly each vehicle at least 40 times. That's 40 launches x 50 vehicles / 10 years: 200 launches per year. If you cut the price of a launch to $10 million and miraculously managed to squeeze 200 flights out of an airframe, you're going to need 1000 launches per year to pay for the fleet. What sort of new market is going to suddenly appear that is capable of paying $10 million for a flight to LEO 20 times per week? This is why Skylon will never fly: it requires an upfront investment in billions of dollars, with no promise of a future market and no promise of even technically working. Airliners and military aircraft projects have a market, with firm orders years before the first test flight and minimal risk. tl;dr There currently simply isn't a mass market for hundreds of Skylons with daily or weekly orbital launches, even at the cost of an airline ticket. Which is why EADS, BAE Systems, Rolls Royce or Boeing and Lockheed Martin are not lining up to buy their idea.

The 1st flight of SLS is Orion EM-1 and is scheduled for 2017 as an unmanned lunar flyby. The 2nd flight of SLS is Orion EM-2 in 2021, maybe. The launch tower is for the Orion EFT-1 flight, which launches on a Delta IV. It has nothing to do with SLS. Also, the EFT-1 launch tower is a boilerplate, not the real thing. You're comparing apples and oranges. Dragon is a capsule. Dragon X doesn't exist. SLS is a rocket. ESA is unrelated to either. It's a government funded agency, not a company. And as such, it's about as transparent as it gets. Pretty much all of NASA's activities, including their plans for SLS, are in the public domain and on http://www.nasa.gov/

Rocket fuel is the cheapest part of the launch. You will always need a huge amount of energy to reach orbital speed. You will always need a damn heavy vehicle to carry that amount of energy. Adding a giant airplane into the equation doesn't make it cheaper. It makes it more complex, more dangerous, and more expensive. And expendable rockets are made to be expendable, which makes them relatively cheap compared to an airplane.

You're wrong. It takes approximately a decade to design and build a spacecraft, from the initial funding decision to the launch. Even if the budget for a payload was voted today, it still couldn't fly until at least 5 years after SLS is operational. Which means that all the NASA employees and infrastructure that are needed to operate SLS will be sitting around doing secondary work and costing millions of dollars while waiting for a payload. Millions of dollars that won't be available to build the payloads. Maybe we will get some lunar flyby stunts, but there will be questions raised in Congress and in the public about the wiseness of maintaining SLS capability for only a handful of payloads. If Congress wants SLS to be useful, then they should be funding missions and payloads NOW, at the same time. The problem is, they are not interested in SLS being useful or in space exploration. All they want is to keep NASA money flowing into their jurisdictions. December is the EFT-1 launch of an Orion prototype on Delta IV. It's not SLS.

Ah, I have fond memories of the days of usenet.

What doesn't make sense? Just like everything else, space hardware has an expiration date. It has rubber seals, tubes, lubricants, filters that have a limited life. It has tanks that have a limited number of tanking cycles. It has solar panels and batteries that need replacing. It has communication and data processing equipment that gets old and obsolete. External paint and insulation is bombarded with UV rays. It has consumable fluids and gasses that need replacing. And all of this hardware is running 24/7 in an extreme environment with vacuum and extreme temperature variations. At one point, it becomes cheaper to build a new module than to fix and upgrade the old one. It's not much different to a car or a computer really... Mir had suffered some major problems, including fires, leaks, and some modules had to be shut off completely. It had been repaired with duct tape and wires and pipes running through the access tunnels. The life support systems were outdated and insufficient. It's a miracle that it lasted as long as it did. It was also in an orbit that was convenient to reach from Baikonur, but not necessarily optimal for access by the Space Shuttle. So it wouldn't have been a great basis for the ISS.

Doomed? I dunno, but nothing lasts forever, not our own lives, not humanity, not even stars. I can live with that and just enjoy what life offers while I can. Old stuff gets always replaced with new stuff, so it's no big deal in the grand scale of the Universe. Space isn't hopeless, but with our current technology, it's not much more than a big expanse of nothingness where we can't do much. It isn't hopeless, but maybe it is a bit pointless in the foreseeable future. And yes, as you have pointed out, it's a chicken and egg cycle. The only way out of that cycle is going to be through decades of slow incremental improvements, until we reach a balance between offer and demand. It's unlikely that we see some magical breakthrough in physics that reduces the energy cost of accelerating stuff to orbital speed. Space is an extreme environment, like Antarctica, the Gobi desert, the summit of Mount Everest, or the Mariana Trench. These places are interesting to study, inspiring to explore, and might have some niche commercial applications one day, but they are never going to be booming with activity because they will always be difficult to reach and difficult to survive in.

What you were saying was that reducing cost *automatically* increases demand. I'm glad you seem to have realized that this is not *always* true and that it is much more complicated than your *basic* rule. You insist that reusability yields some sort of huge cost savings. Again, let's take an example of the costs of running a launch business. - Booster R&D - Booster manufacturing - Booster testing - Launch site facilities - Transportation - Stacking - Payload integration - Propellant - Launch operation - Sales and Marketing - Administration and HR Now, for each of these steps, you need to pay people. Salaries are the biggest cost factor here, not the material of which the rocket is made. A few tons of aluminium is cheap compared to the salaries of the folks who are needed to operate the company. Reusability only removes the Booster production step. The only cost savings are: the material needed to build the booster and salaries of the people on the manufacturing floor. With a 10 time reusability as envisioned by SpaceX, you still need to maintain a manufacturing facility with a lower production capability (and therefore a higher unit cost because you lose in terms of economies of scale), so you don't even save that much. You still need the hundreds of people in all the other departments. In fact, if your launch rates increase, you actually need more people in these departments. That's where most of the cost is. The actual booster hardware is maybe around 20% of the total launch cost, at best. If you reuse it 10 times, then you can cut your total launch cost by 18% at best. On the other hand, you will have increased the R&D cost and the individual cost of the booster (which now has to be much more robust and is produced in lower numbers). The economy due to reusability is marginal at best. No, my arguments about why Skylon is unrealistic is in those threads. If you want to insist that Skylon is going to happen, you need to address my arguments in those threads. I've provided my numbers and my demonstration. The onus is on you to demonstrate that it is feasible if you want to keep on using Skylon as an example. I'd like to see those examples. You can reduce some of the cost, yes, but not all of it. And because a 90% reduction in launch cost is not realistic, then hypothesizing about other costs if that happened is pointless. To support any business case for "cheap" launches, you are going to need to demonstrate first that there is demand for 500 launches per year instead of 50. There simply isn't. In fact, it's the opposite. The current market is saturated and the demand for GEO comsats is going to decrease because their latency makes them really only useful for broadcast, which is becoming a niche market. In a few years, the bulk of communication, including TV broadcast, will be through LTE and optical fiber links. Without even talking about launch cost, cell towers require a lot less energy to operate than GEO satellites.

An N1 as a nuclear weapon would be useless. It takes weeks to prepare and fuel liquid rockets for launch. Baikonur would have been vitrified before the N1 was even rolled out of its hangar.

Maybe you should try to understand instead of trying to explain. The technology in cars has increased dramatically over the last decade. Prices not so much. You are getting more technology for the same price, hence they are cheaper. But that wasn't the point. The was that you claimed that reducing the cost automatically increases the market. I used cars, but I could have used hamburgers or refrigerators. Reducing the price of hamburgers will not automatically create new markets for hamburgers. You claim that reducing the cost automatically increases the market is wrong. Therefore it is not a universal economical rule. You didn't even read the link I gave you to the Skylon thread, did you? You keep on droning on about Skylon. I've already asked you to stop using it as an example because it simply isn't realistic. None of their technology exists and their business model estimates are all wrong. Yes, I do. This is an example of a basic rundown of the costs of an operational satellite. - Spacecraft $300 million. - Ground systems: $100 million - Launch: $100 million. If you reduce the launch cost to 10$ million, you only reduce the total cost of the project from $500 million to $410 million. That sort of reduction will not open up new markets. And I've already explained why 90% is not realistic, by any standard. Please stop using that number. SpaceX claims a realistic reduction of around 10 or 20% in the long term. If you are so certain about your 90% number, then go ahead and show us how you combine development cost, unit cost, infrastructure cost, and flight rates to bring launch costs down by 90%. No it doesn't. I already explained why in my previous post, which you ignored. I already told you that you the hardware cost is only a small part of the launch cost. But you are ignoring what I explained. Skylon again? No it isn't, and I already explained why. I'm done talking with. You keep on ignoring everything we say and stick to your idiotic claims to the point where this discussion isn't going anywhere. Let's meet again in 10 years and look at where Skylon and SpaceX are. Then we can decide who was right.

Probably not. To perform the same kind of work, a human geologist would need a 500 kg of lab material, a mobile lab, and some heavy life support equipment. He would have to drive his mobile lab, prepare for an EVA, egress the rover, pick up his sample, ingress the rover, take off his suit, and run his experiments. He'd also have to stop to eat and sleep and would only be operational half of the time. He would also have to remain in a safe radius around his Mars Ascent Vehicle and would only be able to stay on the surface for a few weeks or months. The whole expedition would cost $100 billion. For the cost of a manned mission, we can send hundreds of MSLs to all sorts of different places and get decades of scientific data out of them.

You should, if you want to participate in the discussion. Mars One is specifically a one-way manned mission as the basis of a TV show. What you suggest would not be Mars One.

It's the biggest one in our solar system.

Also I don't see why "big and dumb" would automatically be cheap. Your average container ship is big, dumb, and made of steel, and still costs more than a Falcon 9 launch.

Animals are less affected by humans because their average lifespan is shorter, therefore they die of natural causes before any cancer or leukemia has time to develop.