Kryten

How are you supposed to be saving this $75 million in the first place when you still have to pay the idle rocket production workers? They're not saving on components to a significant degree because they have very few external component providers, and materials cost are not going to be remotely that high.

The gap is between the oxidiser and fuel tanks of the (simulated, in this flight) upper stage, and the tanks on the boosters are part of the thrust vectoring mechanism.

Show me something that's not nanotubes that can do an order of magnitude or more more tensile strength than existing alloys; and cheaply. That's the kind of stuff you're asking for here. SpaceX. If somebody had a robust model for lower operating costs, they'd be using it. You just admitted 'build it and they will come' isn't true in this case-in other the launch provider can't create the demand.

Pretty much. You won't get significant results without massive improvements in tensile strength, given the aforementioned balloon tanks. They're already less than a cm thick, no normal material is going to go much less than that with a useful pressure. Major improvements-things like SSTO-aren't viable without majorly increased demand. The expendable, multistage rocket paradigm is around for a reason. He's just stating that 'build them and they will come' doesn't work in this business. Given the number of people that have gone bust banking on it that's basically an established fact. There's no way for the launch provider to increase demand. That's not the same as saying demand can't increase.

It's about the theoretical maximum without nanotubes or somesuch. Nobody even builds their rockets with balloon tank first stages since Atlas due to the manufacturing and handling costs, they're not going to be making rockets out of nanotubes. I've acknowledged there's room for improvement in economic a good few times, as has Nibb, including in his original post. Again, did you actually read it?

For dry mass, theoretical maximum is effectively Atlas-Centaur, without poking into materials that don't really exist yet. Both stages were thin enough to collapse without pressurisation-you can't improve dry mass significantly from that without running out of rocket to shave off. We're already at the point where engine T/W is good enough for them to be only a few percent of dry mass; what other parameters could their be?

You specifically asked me to point out where somebody had computed those values, now you're complaining that I did. EDIT: And where else is this revolutionary increase in performance supposed to come from? We already have stages that can't even hold up their own weight without pressurisation, so you're not going to majorly improve dry mass without running out of rocket-all that leaves you is economic factors, which Nibb acknowledged. Did you actually read his post?

Plenty of people have done that-here's one good example. You get somewhat differing results depending on assumptions like chamber pressure and O/F ratio, note, but nobody is saying there's a huge load of untapped potential. Note it also gives direct energy efficiency for a good few engines-all above 90%. It depends on the assumptions you've made in the calculation-but the site linked above, the least conservative I've seen with these assumptions, gives about 390. There's room for improvement, but not revolutionary improvement.

The theoretical maximum Isp for a Hydrolox engine is about 470 seconds; RS-25 (developed late 70's) has 450 seconds. Kerolox maximum Isp is about 360, NK-33 has 331. There is plenty of room for innovation and ideas in spaceflight but chemical engines isn't it, at least if you're expecting some massive breakthrough in efficiency.

Falcon Heavy payload to TLI is about 15 tons. Would require cut-down service module for a free-return flight.

India's GSLV Mk. III rocket is planned to fly it's first mission at about 4:00 UTC/GMT (i.e. 23 hours after this post). Live coverage should be available here(Indian national news), here(directly from ISRO), and via youtube The payload is a prototype for an Indian crewed capsule, CARE, the full version of which is planned to fly on Mk. III sometime after 2020.

Yes, but what does that 75% cost actually contain? It's not going to be components-in a company with such a large amount of vertical integration-and it's not exactly to be materials, so what's left? Labour. How do you eliminate labour costs? Massively reducing the construction workforce. Will F9R allow him to do that? It's not at all likely, given the limited number of times a rocket would be able to be reused. So where are the savings?

Finding biosignatures would be part of the job of the terrestrial labs analysing the 2020 rover samples. Otherwise we're running into instruments that are simply extremely hard to fit on a rover and within the power and data budgets.

But you haven't got 'an idea', and you haven't done the slightest bit of research to see if such an 'idea' is even possible. Radically increasing the performance of chemical rockets from what we have now isn't going to work not because of lack of 'ideas', it's not going to happen because we're already close to the limits imposed by physics and chemistry, and have been since the 60s or 70s.

The return mission is currently very much in flux (read: nobody wants to pay for it at this point), but would likely be a joint mission with another agency.

RD-193 (under RD-181 designation for export) has been confirmed as the new engine for Antares.

The 2020 rover is intended to cache samples for future return-the focus for the instrument suite is to find the best samples. It has enhanced ability to detect organics as part of that, but just detecting organics in itself would test us very little about possible life. After all, given what we know about comets and C-class asteroids, Mars has to be being bombarded with organics all the time.

If you won't, I will. I hope they bleed them dry.

Expect increased focus on anything that brings in foreign revenue-Dnepr, ILS, cooperative science missions-to the detriment of entirely domestic programmes. As a specific example, the new Luna missions are likely to at least be heavily delayed. Exomars may be in trouble also, given then funding from the European side has itself been squeezed-expect delays there as well.

I thought people had finally cottoned on that global warming and ozone depletion are completely different things with different mechanisms. Sadly not.

if you can't make an economic case for pushing mass into orbit, you most certainly can't make a case with the same technology pushing mass to Australia. Particular as the majority of businesspeople that were assumed Concorde customers turned out to be just fine with normal flights, and the rest got their own jets.

ln is a function, like finding the square root of something. You take the value you get by dividing the masses and do ln on it.

No, because then your rocket would reach the same speed no matter how much payload you had on it.

Exhaust velocity is Isp divided by 9.81. You aren't going to get ÃŽâ€V without using some version of the Tsiolkovsky rocket equation, and the version with ln is going to be the easiest. Just suck it up and use a calculator, there should be a perfectly serviceable one as part of your computer's OS.

Or you could divide m0 by m1, take that value, put it into windows calculator, and press the 'ln' button. If you're a wimp.