Nibb31

The X-37 was flying 4 years ago. Dragon 1 wasn't. Dragon 2 still isn't. The USAF didn't pay for it, they got it for free when NASA decided they wanted to cancel it. What competition ? It's a top secret USAF X-project. There is no competition.

The RCS uses hypergolic propellant. Nasty stuff.

Voskhod 3 and 4 were supposed to be a 19 and 20-day missions, but they were cancelled.

Launchers don't typically launch the satellites to GEO directly. Usually, the upper stage puts the satellite into GTO (geostationary transfer orbit), which is an orbit with an apogee at GSO altitude and a low perigee, and is discarded. That is where the launcher's responsibility ends and the satellite operator takes over. However, they don't go straight from GTO to GEO in one go. They typically orbit in GTO a couple of times while systems are checked out and deployed. Also, satellites are usually equipped with small thrusters (their main purpose is station keeping), so the satellite has to raise its perigee over multiple apogee burns. This means that it might take a dozen of GTO orbits to actually reach GEO. Of course, each of these burns are carefully planned, and with the final burn circularizing the satellite in the target longitude position. The number of GTO orbits, the apogee manoeuvers, as well as sun exposure and battery life, determine the launch window.

I don't see why not. If zero G manufacturing ever becomes a thing, it will most likely use unmanned orbital platforms like X-37 or DragonLab.

You need more than iron to make a robot. You also need sealant, isolation, lubricants, solvents, and lots of fairly complex components made with all sorts of materials that would also need to be sourced locally. For example, electronic component production needs all sorts chemicals. On Earth, making something as simple as a switch, a transistor or an air filter requires a complex industrial supply chain that we can take for granted. Making those things out of Mars rock would be a huge challenge.

There would be no need to make it reusable. Just launch a dozen of expendable ones on a single launch instead, or make a big one with enough propellant to last 20 years. The X-37 is constantly tracked by amateur astronomers. It would be instantly detected. A kinetic weapon doesn't need much maintenance. If you're going to relaunch an upgraded sat, then just launch a second one and keep the other one up there as a bonus.

There are fixed costs and per volume costs. Attempting to separate one from the other is a mistake. It is very difficult to to determine the actual cost of a single launch vehicle, because it depends on the fixed costs divided by the number of launches. The price of a launch includes: - Several years of R&D - Production (including sourcing, testing, firing ranges) - Consumables (propellant) - Launch Infrastructure (multiple launch sites, fuel storage, factories, IT, coms, mission control) - Integration (white rooms, power and test fixtures) - Logistics and handling (transporting people and stuff around) - Sales and Marketing (PR, selling flights, responding to RFPs, etc...) - Business stuff (finance, taxes, operations, HR, IT, maintenance, catering, etc...) - Taxes - Employee benefits - Profit (if any) for the shareholders To manage all that stuff, a company like SpaceX pays for thousands of highly qualified (=very expensive) employees and maintains some very expensive facilities. The cost of the actual rocket is only a small fraction of the $60 million price tag (which is why reusablity isn't as big a deal as some people think it might be).

They can be rebuilt after the siesmic shock. I'm not saying it would be easy, or that there wouldn't be billions of casualties, but there are more chances for a decent number of humans to survive a doomsday scenario on Earth than a power failure on a Mars colony.

You don't land a billion dollar spacecraft containing new top-secret technology and military-grade materials in enemy territory to abandon it there. You want to be sure you'll get it back. And the advantage, compared to sending in a Chinook or an Osprey is... ? Just stick a capsule on an ICBM. No need for an orbital spaceplane.

If Humanity is destroyed, then there isn't much point in having a backup. It's not like you could rebuild everything or bring people back. If everything is gone, you won't be there to lament about it being gone and there won't be anyone left to care. But seriously, what sort of event could really wipe out Humanity totally? If we can survive in closed-loop habitats on Mars, we could survive any of the extinction-event impactors that have hit Earth in the past. We could dig ourselves underground and live off the same hydroponic tomatoes and recycled urine that would keep us alive in space. Even if 99% of humanity was wiped out, there would still be millions of survivors that would still find life much easier on a scorched Earth than on Mars.

An X-37 would be an easy target. It's only hypersonic for a short period, but that would be outside of the theater of operations anyway. After reentry, it goes subsonic, it glides down on a very predictable trajectory at a medium altitude, and is still glowing hot with no evasion capability. I see no reason why it couldn't be easily detected and shot down a few kilometers from its landing zone. But why would you need to launch 5 guys into orbit on an Atlas V from Vandenberg AFB to make them land at a friendly base in one of those countries? The region is surrounded by thousands of troops in US and NATO bases, US Navy supercarriers, and mid-air refueling is a thing. It would make a nice movie, but in real-life you could buy them a plane ticket and get there faster. There is no location in the world where you couldn't get a carrier group or stage substantial ground troops in less time than it takes to prepare an Atlas V launch.

What you are describing there is a lot like NASA's Design Reference Mission for Mars. There have been several iterations of it, the latest being DRM 5.0 that involved (cancelled) Ares V launches: Although in this case, you would only need the cargo lander. If you had all the hardware available, you could probably do the one way cargo mission with 100 tons to Mars in two SLS launches, one for the propulsion stage, the other for the spacecraft. If you don't do aerobraking, 90% of those 100 tons would have to be propellant to perform the landing, the 10% left would be the spacecraft and you might have a few pounds of actual payload. Arrival at Mars really does require aerobraking (typically, several passes) so you would have to land at the foot of Olympus Mons, which is probably a few hundred kilometers from the summit. Launch windows to Mars occur every 18 months and the journey is around 6 months. You would have to launch your spacecraft stage first and the propulsion stage at the last minute because of boil-off. Cryo rocket fuel can't hang around in orbit for more than a few days. You would need to build a factory to produce the LH2 and LOX for the rocket engines, the cryo storage tanks, and everything needed to handle rocket fuel. If your rocket uses SRBs, you are also going to need to make them. They aren't usually left around fully fueled in storage and chemicals have a shelf life.

Reusability actually goes against economies of scale. If you were suddenly able to reuse your rocket stages 10 times without multiplying the number of launches by 10, the actual cost of each rocket stage goes up, not only because a reusable stage is more complex than an expendable one, but also because you still have the same fixed costs to build those stages and you are producing less of them. And there is no market for 10 times more launches than what we have now, even if you divided the launch cost by 10 (which simply reusing hardware can't). But even if you do manage to reduce hardware costs through mass production, the cost of going to orbit will always be super-expensive, simply because the amount of energy needed to accelerate stuff to 27000 km/h is huge. Large amounts of energy are expensive to produce, to store, to handle, and to convert into velocity.

Only if: - The target runway is long enough for the X-37 to land on. - The runway is already under your control so that you can retrieve your billion dollar spaceplane without exposing it to the enemy. - You don't care that everybody can detect the straight-line hypersonic reentry trajectory and shoot it down with a 1960-era heat-seeking SAM. - The mission is worth paying $250 million for an Atlas V launch that is prepared months in advance. - You only need to drop 3 or 4 troops. Besides, there is no need to go all the way to orbit and loiter there for a 500 days in this scenario. Seriously, a C-130 will be quicker to deploy, cheaper, safer, and carries way more payload. Could be, but it would still be cheaper to launch it on an expendable rocket, and the payload really isn't very big for HD optics. I put this into the category of "testing long-duration exposure of new top secret materials".

I don't know where you picked that up. There was no propellant transfer in the Apollo architecture. The LM and CM were loaded on the pad. The cryo stir was a routine action that had to be done on a regular basis to prevent the fuel and oxidyzer from solidifying to maintain temperature uniformity inside the tanks. However, you're right that propellant transfer has existed for a long time. It was first experimented between a Soyuz and Salyut 5 and fully integrated into the Progress spacecraft for Mir operations.

Please read the forum before posting: http://forum.kerbalspaceprogram.com/threads/96902-Lockheed-claims-breakthrough-on-fusion-energy-project

Searching for the name in the article and Lockheed points to this wikipedia article: http://en.wikipedia.org/wiki/High_beta_fusion_reactor It looks like they have been making various presentations of it for a couple of years.

Vega. Also Pegasus, but it's cheating a bit.

The launch vehicle would need extra sensors, instrumentation, and thrust termination systems. Which would require new wiring and new avionics. Those are heavy mods. It would also require lots of studies and paperwork to ensure that all failure modes throughout the flight profile are safe for abort. You also need upgrades to the launch infrastructure, training for all the personnel involved, communication channels and presence of recovery forces in the abort zones. None of this is trivial or cheap.

The USAF has been playing with experimental stealth satellites (they have to be small enough to not be easily detected and covered with radar/light absorbing material), but the X37B is not one of them and there is no way an orbital launch can go undetected these days. Launch any rocket into a polar orbit without announcing it beforehand, and red telephones will be ringing between Washington and Moscow.

100 megawatts in the back of a truck? I wonder what happens if it gets rear-ended. also: doesn't give me much confidence in whoever wrote the article.

Of course. Satellite launches and orbits cannot be held secret. There are amateur sites such as Heavens Above who permanently track everything. Anything the X-37B does is monitored permanently: http://www.heavens-above.com/PassSummary.aspx?satid=39025&lat=0&lng=0&loc=Unspecified&alt=0&tz=UCT If the X37B approached any other nation's satellite, they would notice. It would be a pretty obvious manoeuver and would certainly trigger protests (and retaliation) from the targetted country. Note that the Heavens Above site has a "Close Encounters" feature, which will tell you if it ever gets within 5km of another object. And again, why would you want to bring back a spy-sat? Instead of wasting payload mass on wings, wheels, TPS, hydraulics, and avionics, just add more propellant and make it last 20 years, or make it smaller and stealthier. The X37B would be a rather poor weapon platform. Why would you want to bring back a weapon platform every year or two? Just leave it up there and use the extra payload for more propellant or a bigger weapon. I think we would have noticed if it had been maneuvering all over the place with a magical propulsion technology. It does perform some orbital changes, but nothing that suggests a secret new warp drive. Proceeding by elimination, my personal guess is that it's used for experimental orbital manufacturing (growing crystals, wafers or microfibers in microgravity) or long duration exposure testing of new materials. Whatever they have on board is something that they want to bring back to use on Earth which means that it is valuable or rare or impossible to obtain otherwise, and no other purpose makes any sense.

Rubbish. Very few asteroids share the same orbits. Going from one orbital inclination to another is extremely expensive in terms of delta-v and can potentially take years. Flybys can be coordinated if you're lucky, but actually matching orbits is hard and expensive, even more so if you are moving hundreds of tons of construction material from one orbit to another. Humans have only ever migrated to pursue a better life. That is human nature. We seek to increase the wealth, the comfort, or the safety of ourselves and our children. Migrating to space increases none of those things. In fact, living in space typically costs more, is less comfortable, and much more dangerous than living in even the most inhospitable places on our planet. It might be fun to travel to space for the thrill of a short vacation or an adventurous job opportunity, but moving their permanently with your children and expecting them to have a better life than they would have anywhere on Earth is simply wreckless.

What makes you think that?