Nibb31

Congratulations, you've just figured out the principle of cryo propellants. The point is that by lowering temperature, you raise density, which means that you can build smaller (and therefore lighter) tanks for the same number of molecules. Oxygen and hydrogen take up less space when they are liquid than when they are gaseous but they have to be chilled a lot to become liquid. And yes, they do need active cooling when they are on the pad, and they do have to detank when a launch is scrubbed, and tanks have a limited number of tanking cycles. This is also why they use foam insulation on cryo tanks, and why you can't easily keep cryo fuels on orbit, and long duration missions require either storable propellants or active cryo equipment.

SpaceX has an American flag on its rockets. Up until now, commercial rockets have been sticking to maritime tradition by carrying the flag of their country of registration. Oh, and SpaceX isn't going anywhere without somebody paying for the trip. Even if SpaceX gets to Mars, it will probably be a chartered flight by NASA or an international mission.

I think it's something like 10%. The F9 is actually quite a bit bigger than Soyuz (which is a different class of launcher) and slightly shorter than Atlas V. You just sacrifice some payload fraction to compensate for the extra fuel and trajectory loss. What F9 has that the others don't is the ability to throttle down (each individual engine, plus using only 1 out of engines). That's the key capability for pulling off a vertical landing.

Not sure what you mean. If they don't reverse their horizontal velocity, they land in the ocean. The whole point of the exercice is to achieve RTLS, not a barge landing. There is a dog-leg burn at the end so that if the burn fails, it crashes into the sea and doesn't destroy the pad. http://i.imgur.com/D9BdO86.png

Mars-3 landed a Soviet flag in 1972.

Only just saw it on YouTube, that was an astounding mission ! Congratulations SpaceX !

Dunno why you are necroing, but a mass accelerator shooting ordnance as a weapon would be called a railgun. https://www.youtube.com/watch?v=o4ZqfEJTGzw

I'm not saying it's not enjoyable. I've only watched the first two episodes and it's really quite good, but I don't see what's accurate about it. The universe seems to be a mix of BSG and Alien. The ships seem to have their engines lit up all the time (unless they are just big tail lights) whenever they are moving and everyone evaluates distance in terms of kilometers which is meaningless in terms of space navigation. An enemy ship being 80000 km away is meaningless if you don't know their trajectory. They could be 10 km away, but on a course that would make interception impossible. In reality, they should be reasoning in terms of dV and orbit. Sci-fi is only fantasy where the "magic" plot device is replaced with technobabble. In pretty much any science fiction story, you can replace aliens with trolls and dragons, and technology with magic, and it would still work. That doesn't mean that it isn't good entertainment, but you have to take it for what it is, fantasy, not science.

That's still technology development. As you say, there is nothing about ARM that is funded. NASA doesn't have authorization from Congress to proceed with the ARM mission. In fact, nobody seems to even be mentioning it any more... Yes, and any decision from the next administration will also be preceeded by some sort of committee report (you don't cancel a multi-billion dollar program without spending a few million on an expert commission). Which means that you won't get any decision before at least a year. BEO payloads for a heavy launch vehicle will have to be large projects, which means that they will have to be expensive, which means that the decisions to start them won't be easy to make. That's why there have been no decisions yet. The more Congress waits, the more SLS is going to sit in a hangar waiting for something to launch. This isn't exactly a problem for them, because what the politicians want is for NASA to pay big juicy development contracts to their constituants. What happens after the development phase ends isn't their problem. The problem is that every large project takes years to arrive from inception to launch, and NASA doesn't have the money to run several large development projects at the same time, which means that there is no way SLS will ever have a large mission to launch every year, which means that it will always be sitting around wasting money while waiting for payloads. Morpheus was a small scale lander, mainly to study landing technology and software. To scale it up as a manned lander would still be major 10-year development project. And there is no leftover hardware from the ISS. STS actually had plenty of payloads and missions lined up while it was being designed. It turned out that many of them were unrealistic, but it was nothing like the emptiness of SLS's manifest. Constellation was also based on STS hardware.

Are you guys really talking about "science" for a show where spaceships stop when they switch off their engines or where the actors keep their Hollywood hairdo under zero-g ?

ARM has not been authorized by the US Congress. There is still no development funding for the mission hardware. Requesting a new space policy will not be among the first decisions of the next administration. If there are any space policy changes, they won't happen until at least two years into the next mandate. So there won't be any funding decisions made for any BEO missions for the next couple of years. Add the 10-year lead time that it takes to complete any major aerospace these days, and you'll see that the SLS will be sitting around for years with no payloads. With no flights, high infrastructure maintenance costs, and no major payloads that are relying on it, it is a prime candidate for cancellation. Because there aren't any Apollo rockets left. The lines were shut down, the tooling was scrapped, the suppliers have disappeared. You can't revive 1960's technology because manufacturing processes and materials have changed. You would need to redesign every single part with modern techniques and materials, which would be more expensive and less efficient than redesigning from scratch based on today's technology. Which is basically what they are doing with SLS.

None of those payloads are funded or committed to. They are notional concepts at best with no political or financial backing. From the moment Congress gives the kick-off to the moment they are ready for launch, you need to count 10 years. When you have an infrastructure that costs you $2 billion per year just in maintenance, and you only use it every 2 years, it just doesn't make sense to keep it. At one point, someone is going to notice the money sink and shut it down.

Not really, no. It takes pretty much a decade to develop any new major spacecraft, and lander is no exception. That means that I don't see how they could develop a Moon lander any earlier than 2025, which is 4 years after EM-2. A whole other presidential cycle. One launch every 4 years (or even every 2 years if they manage to fit Europa Clipper in between) is not enough to amortize the infrastructure. With no payloads in the pipe, SLS is a sure candidate for cancellation after EM-2, but probably before that.

Linux certainly isn't for everyone. For all its problems, Windows just works out of the box and most people know how to use it intuitively. Linux usually doesn't, and many of the programs that most people are used to on Windows aren't available. Linux is great for a server. I have a home server that runs Debian, and for that purpose I really enjoy it. But for a desktop/laptop/everyday computer, Windows is perfectly adequate. PS. I'm not touching anything Apple with 10-foot pole.

SLS development costs $10 billion. Pad infrastructure upgrades are $2 billion. Then, the unit cost for each launch is $500 000 (low estimate). If you only launch it a dozen times, then each launch will have cost the taxpayer $1.5 billion, which is 6 times the cost of a Delta IV Heavy and 15 times the cost of a F9H. However, there are only 3 launches planned: EM-1, EM-2, and maybe the Europa Clipper. Anything beyond that is speculation at this point.

They can say what they want. They are in the business to attract investors in order to keep paying the bills. There is no way they will ever be profitable. Asteroid mining might become a thing one day, but not in our lifetimes, and it certainly will not involve humans living in space. If you're in a business to make money, you don't want to make stuff more expensive by man rating everything and adding life support and habitation volume. Teleoperation and IA can already do wonders, and there's no reason to believe that robots won't get better in the future.

Good luck with that. Either you put your orbital stations in GSO and you beam down to a single ground station 36000 below (say goodby to a "focused" beam) or they are in LEO and have to constantly repoint themselves to a different ground station, which is going to cause more loss. Oh and those microwave array ground stations aren't going to be cheap either. I suspect that solar panels are way cheaper than just the microwave converters, let alone the space factories and orbital power stations. But this should be moved to a separate topic because it really doesn't have much to do with BFR/MCT plans.

Those figures are as pessimistic as it gets, but who cares. Just build your ground-based solar farm in the desert and make it 10 times larger than your orbital solar farm. It will still cost 10 times less (at least). Which will cost how many times more than a conventional solar panel factory?

No way can orbital solar be competitive against ground solar. Even if ground solar had half the efficiency, you can simply double the surface at very little cost. The difference between putting a solar panel on the ground and putting one in space is several orders of magnitude, as is the cost of manufacturing one on the ground and manufacturing one in space, and that is without adding in the losses, environmental impact, and extra costs of the microwave transmission (which is something that has never been tested).

Yeah, I was misled by the article that quoted the announcement from SpaceX HQ at Hawthorne, but the static test is at the pad. Got it.

Do they really plan a hot fire a Hawthorne and launch the same rocket 2 days later from Canaveral ? That can be possible.

No, but he still needs a business plan if he wants to raise the money to do it. He "only" has $14 billion, and that money is tied up in his companies so he can't spend it. And the people who go there are also going to need a business plan. People and corporations won't invest money if the only activity is survival. Somebody has to spend a lot of money to keep all those people alive, and it's only worth it if there is much more money to be made.

Explorers are not settlers. Those 17th Century colonies also weren't very successful... There aren't any minerals on Mars that would be economical to trade with Earth.

Barnstorming was never a big contribution to air travel. It didn't really boost design and mass production of barnstorming planes, nor did it evolve into a large industry. The reason why analogies with air travel fall flat is that there was huge demand for fast transportation from point A to point B before the airplane was even invented, or before rail or ships. People have always needed to travel to real destinations where people live and work, so that they could meet friends and relatives, conduct business, exchange goods, or just visit. Space is not a destination, it's litterally the middle of nowhere, and people have no reason to go there. Air travel was a solution to a problem. Space travel is a solution to a non-existing problem. With no existing demand, building a mass transport infrastructure to orbit is like building a bridge to nowhere.

This is not news. 2024 or 2028 have been the working dates for retirement of the ISS for years. The actual date is 2024 and a decision has to be made with the ISS partners if it is extended to 2028.