Nibb31

That's wrong. Actually, 100 years ago, there was a lot of demand for travel. People were cramming themselves into ocean liners by the thousands and railways were being built all over Europe and America. At first, planes were expensive, but they filled a niche because they were fast. From the start, they served a purpose that was obvious to everybody. It took decades for planes to become more and more affordable, over the 60's, 70's, and 80's, but the demand to get quickly from point A to point B was always there. However, the analogy doesn't work for space because space isn't a destination and rockets aren't a form of transport for the masses. People use air travel to actually go somewhere where you can visit family, do tourism, or conduct business. A rocket takes you to orbit, which can be seen as a joyride for a small customer base, it's not an actual destination for mass transport. Currently, there is no demand for frequent launches because there is nothing much to be done in space that can't be done better and cheaper or Earth. For demand to exist, there must be an incentive, a business model. There are lots of ideas, but none of them are viable yet because it's so expensive to get to orbit. Getting to orbit will always be expensive, because the amount of energy that is required to accelerate to 27000km/h is huge, and handling huge amounts of energy like that will always be out of reach of the masses. Don't get me wrong. I think that SpaceX is on the right path for wanting to cut costs, but even if they manage to be 10 or 20% cheaper than the competition, it will take much more than that for any mass-scale business model to emerge.

They were four blokes in a shed for 20 years. They do seem to have been hiring over the last couple of years. I was unable to find an employee headcount, but LinkedIn has them in the 51-200 employee category, which makes them a small business. They seem to be renting a couple of offices in a Culham Innovation Center in Abingdon, UK. They don't have a production center, a test flight facility, or even a runway for that matter. So ok, they are not shed-based, but even as a pure R&D organization, you can't really put them on the same level as Boeing or BAE Systems. Call me back when Burt Rutan puts something in orbit.

Skylon's fuselage structure and outer skin is unique and totally new and unproven. It also doesn't use modern 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. http://www.flightglobal.com/news/articles/skylon-space-plane-places-huge-demands-on-exotic-structural-366179/ It took years for Boeing to industrialize the 787 carbon-fibre fuselage, and it's still much more conventional than Skylon. And Airbus can build four A380s per month. But Airbus and Boeing can do that because they have decades of experience in supply chain management and manufacturing. They have thousands of experienced workers in multiple factories. They have logistic lines in place and approved suppliers. If they had to start from scratch, hiring and training the workforce on new materials and manufacturing techniques, laying out the factories, negociating with subcontractors, designing the tooling, writing the manufacturing and test procedures, etc... It wouldn't take 4 to 5 months. It took Boeing or Airbus decades to develop their manufacturing capability.

That is pure conjecture. Nobody knows what the turnaround times for Falcon stages will be, or how many times they will be able to reuse them. They don't even know if an empty stage can handle the landing or aerodynamic forces without sustaining any damage yet. The Falcon Heavy probably won't use reusable stages anyway, because it seriously cuts into the payload capability, which negates the point of using a heavy launcher. The F9-R will have a 7t to orbit capability instead of 13t for the F9 1.1. This puts it in the same category as Soyuz or Ariane 6. I'm guessing that a reusable Falcon Heavy would be closer to good old Proton and Ariane 5 than to the full 50-ton non-reusable Falcon Heavy. You could build something dwarfing the ISS in a fortnight for a fraction of the cost, then send it on its way to Mars the following week.

Nobody knows that yet. The economics are far more complicated than they seem. For prices to actually come down, SpaceX needs to reach a certain volume of launches. They aren't there yet, and the reusability thing complicates the matter, because it actually hurts their mass production goals. It's not clear whether reusability will be economically viable or whether turn-around times will be shorter. Falcon Heavy can only exist if a certain number of launches exists. One sample return mission, or one or two private payloads, is not enough. And nobody is going to build a 50 ton payload that requires Falcon Heavy until a dozen of other people start building 50 ton payloads that require a Falcon Heavy, because otherwise, they might get stuck with a 50 ton payload and nothing to launch it with. SLS is facing the same problem. It has 2 exploration flights and maybe a DoD flight on its manifest. Three flights is not enough to build the confidence for other government agencies to start designing 70-130t payloads for it. It takes years to build confidence and even more years to build payloads. Payloads will only appear for the rocket when the rocket is actually available. SLS is having the same problem, yet it is actually available. Even if they were actually offered an SLS launch for free, JPL couldn't afford a 70t flagship science mission. And the market for launches to LEO or GEO is not growing at an exponential rate. It's a competitive market, so if SpaceX drops their prices, the others will follow. It's not clear whether the market is big enough to support all the suppliers that are on the market, and launch providers that are backed by government subsidies might turn out to be more robust that private companies. The market analysis is much more complex than "build it and they will come" (which has more often failed than succeeded). I understand that. What I said was that you need to get a sample return rocket with enough delta-V to reach Mars orbit, plus the hardware to rendez-vous and dock with an Earth Return Stage, into a 1-ton package. You also need to build a robotics package that will deploy the rocket from the Dragon, and actually pick up the sample and load it on the rocket, plus the power and comm and avionics packages, all in that 1-ton payload. You also need to develop an autonomous Earth Return Stage that will wait on orbit for your sample carrier rocket and bring it back. And don't forget, it needs some sort of capsule and parachute system to actually get the sample back to Earth. While it is possible to fit all that onto a Falcon Heavy, it still isn't a "cheap" option, and the actual launcher would only be a small part of the project.

It takes Airbus, Boeing, or Lockheed-Martin 10 years to go from a concept to a flying prototype. 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 a factory, they need trucks, they need cranes... There are zero subcontractors who have any experience building SABRE engine, their unique airframe, their 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. Even if Reaction Engines magically got funding on par with the SLS or the F35 program, there is no way 4 blokes in a shed are going to fly a hypersonic SSTO before the end of the decade.

In economical terms, need is expressed by demand, which is equivalent for people willing to pay for a product or service. Although missions to Mars are exciting, the economical demand is not high enough to sustain a market of several heavy launchers. There might be actual demand for one sample return mission, but science mission planners are not going to base their mission architecture around an unproven new launcher that only exists on paper, because if that launcher is cancelled, they lose several years of work. Therefore, if a sample return mission ever happens, it will be designed to go on a proven existing launcher, like Atlas V, Delta IVH... or SLS if they can afford it. Also, don't forget that science missions work on shoestring budgets. A bigger payload means a bigger budget, what NASA calls "flagship missions", and nobody can afford a 50 ton or 130 ton science payload. As for Red Dragon, it has an estimated payload of 1 ton to Mars surface, which is basically the same as Curiosity that launched on an Atlas V. A single ton payload is hardly sufficient to carry enough delta-v to return to Mars orbit and to dock with a return vehicle. The Red Dragon concept seems cheap because it reuses off-the-shelf SpaceX hardware, but it still has to be highly modified, requires new dedicated hardware, and doesn't provide any new capability that we don't already have.

Neither FH, nor SLS, nor even the Musk's MCT, have any payloads, nor do they have anyone willing to pay for them. These sorts of expensive engineering projects only get a green light when there are a certain number of firm orders and a flight manifest. Boeing or Airbus don't start building a new airliner until they have a few hundred firm orders. The F35 only started when a number of militaries signed an agreement to purchase a minimum number of aircraft. The only exception I can think of is actually SLS, where an expensive development program is underway with no minimum number of units being agreed to. And that is what will probably cause its demise after one or two flights. As for FH and MCT, they both have a flight manifest of zero. Powerpoint rockets are cool and exciting, but there is no point in building a rocket that nobody wants to buy.

I'd explain the basics of orbital mechanics, Newton's cannon-on-a-mountain diagram, and how reaching orbit is about flying so fast that you are falling beyond the horizon:

Which one we prefer for what purpose? Personally, to drive down to the grocery store, neither of them beat my car.

Falcon Heavy vs SLS Shuttle vs Soyuz Star Destroyer vs USS Enterprise Apples vs Oranges These comparisons are meaningless unless you define the criteria for determining which is best. Falcon Heavy is a proposal based on some proven technology, but with unproven constraints (higher loads, vastly different flight profiles, propellant crossfeed, etc...). It will only fly when a customer has a payload to launch on it. There are currently zero 50 ton commercial or government payloads waiting for a launcher. Until then, nobody can say it will be cheaper or that turn around will be quicker. Current turn around times are approximately 6 months between flights. It's not clear whether they can improve on those times, or whether there is customer demand for faster turn around times or higher launch rates. The cost is also completely unknown. And both Falcon and Dragon was funded in majority by Government Bureaucracy and controlled by NASA estimate committees.

No. When you go back to state 4, you move the CoM of your contraption exactly back to where it was in state 1. You have not moved. If this was possible, you could move a train just by transferring mass from the first wagon to the last wagon and back again. Or you could get a satellite to change orbits by successively folding and unfolding its solar panels. However, real-life doesn't work that way. Besides, NASA stopped using the "worm" logo more than 20 years ago.

"Video" is a bit of an inappropriate term. There was "TV" footage, which was transmitted live from the LM, and "Film" footage, which was recorded on 16mm film cartridges and brought back. The reason for the poor quality of the Apollo 11 footage is because of the poor quality of small live TV cameras of the era and the low bandwidth. On later Apollo missions, the quality of the live TV cameras improved. The cameras are described here: http://www.myspacemuseum.com/apollocams.htm There is zero doubt at all. Not a single pair-reviewed paper and not a single professional astronomer, geologist, biologist, or scientist from any other field related to the Moon landings has ever expressed any doubts about the Moon landings. That includes scientists from the Soviet Union and pretty much everywhere else in the World.

Talking about sci-fi, one of the things that bugged me about Star Wars was the use of AT-AT walkers in a universe where there anti-gravity/repulsor-lift technology is massively available (i.e. Luke's speeder or Jabba's barge). If the Empire had sent a fleet of heavy-armoured-speeders or repulsor-lift tanks instead of clumsy old walkers, they would have been running in circles around the ruins of the rebel base before they even knew they were coming. Legged robots seem to be the clumsiest and most tactically unsuitable weapon you could imagine.

The biggest issue with restarting in microgravity is that fuel is not settled in the tanks unless you are already accelerating. The fuel floating around in the tank would cause cavitation in the turbopumps, and a rather catastrophic failure. One solution is to use solid ullage motors to provide a small forward motion, which is enough to settle the fuel at the bottom of the tanks. Of course, solids are one-shot, which means that you only get a limited number of restarts.

I suppose if you were coming in from an interplanetary trajectory, you could do a gravity assist and slingshot away from the Earth faster than you came in. This wouldn't apply when reentering from the Moon though.

Normally, if your reentry is too shallow, you will go through the atmosphere and come out on the other side. If your spacecraft generates lift, then you can actually "skip" and raise altitude. However, you will not reach escape velocity unless you were already on an escape trajectory. If you are orbiting Earth, you will continue to orbit and necessarily lose some energy during the skip. This will bring you down deeper on your next perigee. The risk for Apollo wasn't that it would "skip off into outer-space" as the media sometimes said, but that the CM would fly through the atmosphere and go around another orbit (potentially for several days) for which it did not have enough power or supplies to keep the crew alive. It would eventually come back, but as a dead weight.

Charles Bolden claimed that resurrecting the Altair lunar lander would cost 9 to 10 billion dollars. In terms of complexity, I agree that it probably requires more R&D work than a big dumb booster like SLS or even than Orion itself. This would come on top of the spending for Orion and SLS, which will be peaking between 2017 and 2021. I don't think Congress will fund new NASA hardware until the development work ramps down on SLS/MPCV, which won't happen before 2021. Therefore, I don't think that a kick-off date for a lunar landing architecture in 2016 is possible, but if it was, don't count on having an operation lander before 2026 at best. More realistically, 2030 or beyond. Bringing in private companies does not automatically reduce costs. Private companies that are building Orion and SLS are not making it substantially cheaper. SpaceX and Orbital Sciences aren't more private than Lockheed Martin and Boeing, and it's still NASA footing the bill here. Morpheus is not a basis for a lunar lander. It's a demonstrator for landing technology. A lunar lander would not share any commonality with Morpheus, except maybe some software heritage. A satellite at EML-2 would be useless for comms and couldn't communicate with a satellite at EML-1. Neither are really suitable or necessary to support a base at Shackleton. Prospecting to find a suitable location for a base is something that we should be working on, but we aren't. Ideally, there would be several generations of unmanned expeditions, first for prospection, second as ISRU prototypes, and third to prepare for manned activity. These don't rely on SLS or MPCV and could be part of NASA's science budget instead of the HSF budget, even though it relies on a political decision to start a manned base on the Moon. As a comparison, LRO and LCROSS were initiated in 2004 as part of Constellation and launched in 2009. If the budget was approved today, it might be possible to perform the first prospection launches by 2020, but probably not before. It would also take a year or two to analyze the data and to produce a recommendation report for the second generation of ISRU hardware. Count 5 more years for that, and you might have a first ISRU prototype at TRL-6 by 2025 if you're lucky. Optimistally, count at least 5 more years to reach TRL-9, which is the required level for manned operations and evaluation. ARM isn't funded yet, so there is really nothing to cancel and redirect. Oops. With a first EM-1 flight in 2021 and no lander before (at best) 2026, that means that Orion/SLS will be either sitting in hangars burning dollars or flying meaningless circumlunar flights for at least 5 years. By that time, I expect SLS to be cancelled as the ultimate hangar queen, especially if there are any delays on the lander (which there will be). I'm not sure why you would want to mobilize Falcon Heavy while SLS will be twiddling its thumbs. I don't think I would actually develop a Lunar Cargo Vehicle that would fly on FH while at the same time I would be working on a manned lander that would fly on SLS. It would be cheaper to develop a single lander that can be reconfigured to carry either cargo or an ascent vehicle. Both would use the same EDS and launcher. Your whole plan is sound and straightforward, and I pretty much agree with the direction: - Unmanned prospection - ISRU development - Cargo and Hab landing - Long duration manned excursion - Regular crew/cargo rotations However, I cannot agree with the timeline. You seem to think that hardware can be designed and built in months. This might have been true during Apollo, but industry, economy, quality assurance, and project management is different nowadays. Major engineering projects are planned over decades and always exceed budgets and schedules. I can't think of a single modern aircraft project that hasn't taken over a decade from start to delivery, and those use more conventional technology and have a lot more people working on them. I simply don't believe that even if we kicked-off a return to the Moon today, with a huge budget increase and strong political support, we could aim for a manned landing before 2030 at best. Again, I don't see what the incentive for private industry is, other than to receive a paycheck from NASA, which is how NASA has always operated anyway. And I don't see how any of this could be achieved without Congress doubling NASA's budget. Nowadays, there is a limited pool of resources (I mean actual engineers, facilities, computing resources, support personel, etc...). Resources that are working on one project only become available when that project ends. You can't develop SLS, Orion, a manned lander, a cargo lander, prospection probes, ISRU technology and a manned base all in parallel. There is only enough money and headcount to do one thing at a time. For the moment, resources are already stretched between SLS and Orion. When those are done, NASA will be able to concentrate on what comes next. My fear is that SLS has nothing to do during the decade it takes to design what comes next, and I'm not the only one who shares that concern: http://www.nasaspaceflight.com/2014/02/asap-claim-nasa-employing-indecision-roadmap-flexibility/

They already can't find payloads for SLS, so there really is no need for a multi-billion dollar super-heavy triple-core SLS.

Well, the UK is still part of ESA. I didn't mention it, but one of the reasons for the failure of Europa was because of the UK's insistance to use the Black Streak first stage, which simply wasn't up to the task of putting large payloads into a useful orbit. There were also arguments about whether the European launch site should be Woomera or Kourou, and the UK withdrew from the project when the French singlehandedly invested in Kourou. BAE Systems severed its ties with Airbus Group, which owns 30% of Arianespace, but the UK still contributes nearly 10% of ESA's budget. I'd love to see the UK contribute more, and therefore get substantially more out of the deal. Each country has its own specialty in ESA (France does rockets, Italy does pressurized habs, Germany does ATV, etc...) and one area of expertise where ESA is lagging behind is manned spaceflight systems. It would be great to see the UK take the lead in that area.

Shock absorbers do nothing against high Gs. X-37 can't reach a Molniya orbit without everyone noticing. Plus, it would take days or weeks to reach it, which would give the Russians ample time to shoot down every US bird from the sky. And I don't think the X-37 has that much delta-V. To incapacitate a sat, all you need to do is spray it with black paint or a goo-like substance. That will mess with the optics and comms and will make it overheat and die. But you specifically don't want a reusable vehicle for that. A small minisat with a spray can is enough. The smaller the better actually, because it would be undetectable. That would be rather convoluted way of sending a package to troops on the ground. It has far too many limitations: - They need to be near long runway where the X-37 can be retrieved and brought back on a C-17, so why not send a C-17 anyway? - It takes lots of delta-v for a satellite to get itself into the proper inclination, and then multiple orbits to get that inclination over the target. Each Earth orbit is ~90 minutes. If you're going to spend days to preposition your sat into a proper delivery orbit, then again, you might as well put your package on a C-17 and fly direct. - There is no need for any sort of package to loiter on orbit for months. Ignoring the fact that it's against international treaties, it's still much easier to shoot down than an ICBM reentry vehicle and it takes more time to reach its target than a SLBM. Orbital bombing has been proven to be ineffective. What kind of rocket would be needed to launch a troop transport X-37 variant? X-37 fits on an Atlas V with a payload of 200Kg. An X-37C would need a much larger rocket. It already takes months to integrate a payload and prepare for an Atlas V launch, and the X-37 needs a runway to land. How would that be any better than flying your troops to that runway in a business jet or one of those stealth Black Hawks they used to get Bin Laden?

A spaceplane also provides a gentler re-entry and landing, which is pretty important for anything delicate enough that it needs to be manufacturing in microgravity. Why would you need cross-range to interfere with hostile sats ? Why would you even need to re-enter for that matter ? You're not going to takes parts off of an enemy sat or capture it because: - The other party would take that as a casus-belli and you risk retaliation on your own sats. - You have to assume that any military sat is equipped with some sort of anti-tamper system that would incapacitate your own spacecraft. - Why go through so much hassle? If you want to disable it, there are easier ways. If you want intelligence, just take pictures. Fedex is cheaper. At any rate, most military and diplomatic services have their own courier services and transportation methods. Going all the way to orbit just to deliver a 200 Kg parcel makes no sense at all. And there is nothing "quick" about integrating and launching an Atlas V payload. It takes literally months to prepare a launch from Vandenberg. Again, there is nothing stealthy about a straight-line orbital re-entry and landing. It's highly visible from hundreds of kilometers away, and an easy hot target. The launch, orbital maouvers, and re-entry of the X-37 are easily tracked by amateurs with telescopes all over the world. They'd be better off delivering them with a nuclear submarine, an unmarked van or a go-fast speedboat... Launching them to orbit is too risky and too obvious.

They didn't abandon it. They transferred it to ESA, to which the UK is one of the major contributors.

The French space program started, like the US and USSR, after WWII, by tinkering with captured V2s, but that program wasn't very successful and was closed down because the government wanted to concentrate on anti-aircraft missiles. Charles de Gaulle started the french nuclear program in 1958 and it quickly became apparent that rockets would be necessary as a vector for French nukes. The French space program was officially started in 1959, with the creation of CNES in 1962. The first French satellite Asterix was launched into orbit in 1965 on a Diamant rocket from Hammaguir in French Algeria. This made France the 3rd country to develop an orbital launcher. Because of the Algerian independence war, it became clear that France couldn't continue launching from the Sahara launch site, so the Centre Spatial Guyanais was created at Kourou in French Guyana in 1964 and agreement was met with the new Algerian government to allow France to use Hammaguir until 1966 (a similar agreement existed for nuclear tests which were also conducted nearby Hammaguir) About the same time, the ancestor of ESA, called ELDO, was created, including France and the UK, to build a common launcher called (unimaginatively) Europa. Europa was launched from UK's launch site in Woomera, Australia, with a British first stage, a French second stage, a German third stage, an Italian satellite, Dutch telemetry and Belgian ground systems. It was pretty much a failure mainly due to disfunctional cooperation between the various space agencies. ESA is created in 1975. At the time, the UK's contribution is mostly in satellites and Germany concentrates on the Spacelab module that will fly on the Shuttle. However, France is the main contributor to the Ariane launcher program with CNES and French corporations building most of the hardware. The first Ariane 1 rocket was launched from Kourou in 1979, and became the first European launcher capable of putting satellites into GEO orbit. Ariane 2, Ariane 3 and Ariane 4 improved on the design in 1984, 1987, and 1988. Ariane 5 came later, but was more of a clean-sheet ESA design, which is probably off-topic for this post...

In most fiction, wizards, computer geeks, and scientists are interchangeable. Magic and advanced tech are used in exactly the same way as plot devices by Hollywood and book authors. Stick LOTR in a sci-fi universe, and Gandalf would be hacking into the cloud to do his magic, instead of waving his staff. There really is no difference as far as the story is concerned. The rest is just decorum.