Nibb31

Awesome pictures, thanks !

Wouldn't something like CST-100 be cheaper? But you'd still have to pay for it somehow and get US Congress to waiver ITAR. An ARD-derived vehicle (combined with ESA technology developed for the CRV) would be even cheaper and would provide work for European companies. But that boat has sailed, unfortunately.

Nope, it's procedures and more accurate planning that allow same day docking. One of the reasons it took several days to RV with the ISS is because there's a lot of work to do by the crew. From launch preparation (suiting up, boarding, pre-flight activities...) to the actual docking, simplifying procedures has managed to bring the work load down from several days to a well-packed 15 hour work day. The drawback, obviously, is that this puts a lot of pressure on the crews. No, visiting vehicles that are equipped with a CBM (Cygnus, HTV, or Cargo Dragon) need to be berthed by the Canadarm, which is a manual process. Vehicles equipped with a Russian APAS docking system (Shuttle, ATV, Progress, Soyuz) or the new IDS (Crew Dragon or CST-100) can dock autonomously or manually. No it doesn't.

Nobody "flies" rockets. The launch is fully automated. Most spacecraft are flown with computers. Apollo had the AGC, where the pilots entered "verbs" and "nouns" to issue commands. Soyuz has automated sequences, like MechJeb, that can be enabled/disabled by the crew. There are manual controls for maneuvers and docking, although Russian spacecraft also have automatic docking. So using MechJeb is actually much more realistic than messing with the WASD keys.

What about using it as a training ground for testing not *effing* interfering ?

No they don't. We all know what DARPA is, thank you.

I don't think there's the slightest chance it would happen. There actually used to be plans for a crewed version of ATV: http://www.esa.int/Our_Activities/Human_Spaceflight/ATV/ATV_evolution_Advanced_Reentry_Vehicle_ARV The plan was to use it first to return cargo. The capsule would have been based on the ARD from 1998. The capability could later be evolved into a manned vehicle by adding life support and a LAS. Using licensed Orion hardware would be a bad idea. It would be way too big and expensive for its purpose, and you can't fit and Orion on top ov Ariane V. Besides, ITAR prevents NASA from exporting that technology anyway. A crewed ATV would necessarily be much smaller and fully ESA-designed. The service module would rather be based on the ATV SM than on the Orion ESM because it wouldn't need the huge OMS-based main engine (which belongs to NASA anyway).

There were a couple of "mutinies" in the NASA space program. In all cases, the astronauts never flew again.

Department of Defense

It depends on what you want to convey and how your audience will interpret your representation. This sort of representation is bound to be misleading unless it's accompanied with an explanation in very large letters.

The GEO graveyard orbit is only 200 km above actual GEO orbit, so at this scale, it's pretty much the same ring. We've spoken about this representation before, and it's rubbish. The dots are not to scale, they look like they are 50 km wide. In reality, you wouldn't be able to see them.

Yes, this movie set up all the characters and plot for the new trilogy, with lots of winks and references to the old movies. I hope that Episodes 8 and 9 use this basis to move in their own directions instead of rehashing old plots and sprinkling references.

He was only seen as a holo-projection, like the Emperor in TESB. For the same reason: Rebel Alliance => Resistance Death Star => Star Killer Princess Leia => General Organa Sith => Ren Knights Tatooine => Jakku Coruscant => New capital that blows up (forgotten the name) I don't know if it was for merchandising reasons, if it's because Disney wanted to create their own branding, or just to hide that it's using recipes from the original trilogy, but it does seem weird.

Just seen it tonight, I was staying away from this thread until now. At least it was much better than the prequels. Compared to the Darths of the prequels, at least we actually gave a sheet about Kylo Ren. Maybe he needed more character development (and he's going to get it) but he had 10 times more substance than Darth Maul. I just don't get why he feels the need to wear a mask when he takes it off as soon as anybody asks him to. The other supreme leader guy looked a bit too much like space-voldemort to me. The super-mega-death-star-3-plus-with-fluoride was a bit stale. You'd think that they'd have figured out that putting all your resources into a super weapon is a bit dumb, especially as takes less than 30 seconds for the rebels to come up with a plan to blow it up. Oh, and what coincidence that the Falcon, which has been sitting there for years, starts up like it had just come out of an oil change. And what a coincidence that Han and Chewie were just passing by the area to pick them up. Waiter, I don't like coincidences in my movies. We love Star Wars because it's a childhood memory. Watching the original trilogy, to me, is like opening a trunk in the attic with old toys from when you were a kid. This one follows all the same recipes at flaws as the originals. All 3 original movies have their flaws, and that's what makes them so likeable, a bit like your old one-eyed teddy bear or that toy fire engine with with a ladder that couldn't move. Yeah, it has it flaws, and I loved it to bits!

It's not about obligations to customers. It's just that Russia doesn't exactly have a great track record with Mars missions. They have attempted 18 missions to Mars, from 1960 to 2011, all of which were total or partial failures. In that light, it doesn't inspire great confidence.

Each engine is test fired routinely several times before it's launched. This goes for pretty much all liquid engines since the early days. Bill Phil is wrong about this.

It was supposed to be vague and somewhat magical in the original trilogy. Lucas trying to explain it with blood samples and midichlorian counts is one of the things that ruined the prequels.

I've always said that there are very little technological barriers to reusability. I'm pretty confident that they will do it one day. The problems are economical. The same is true for pretty much all of our long term spaceflight goals. When there's a will, there's a way. The technical problems can be fixed, the hard part is justifying those solutions economically and politically.

All of those VTVL SSTO designs are actually pretty cool. I doubt they could have been made SSTO with the materials of the day, but they would make a great reusable first stage.

All liquid engines are test fired at least once before launch. Solid motors aren't (obviously). However, most engines are designed to be disposable. They have a very high performance, but are not designed for servicing (meaning that some parts aren't accessible without taking apart the whole thing) and they are designed for a total lifetime of less than 30 mins. Airliner turbofans, on the other hand, are designed with servicing and long duration in mind. The result is that they are actually much more expensive than rocket engines. Access for maintenance actually adds cost. Rocket engines are a bit like Formula 1 engines: very high performance, but only designed to last one race. After the race, the engine is scrapped.

Actually, it's quite likely that they have made their own trade studies and decided that it didn't make sense, for them, in the their market, to invest a lot of money in a technique that hasn't been proven. Maybe they have determined that it is unlikely that reusability will actually lower their costs (because their organisation is different from SpaceX's), and maybe they have determined that lowering costs doesn't necessarily increase their revenue and that the investiment isn't worth it.

They have a backlog because they haven't launched really many rockets. Some of that backlog (the Orbcomm constellation) comes from cancelling the Falcon 1. A backlog doesn't mean that there is a sustainable increase in launch market volume. In the near term, they can aim for 10 launches/year, which means that they would need: expendable: 10 cores, 10 upper stages, 100 engines. disposable: 1 core, 10 upper stages, 19 engines. A production run of 19 engines/year is going to have a much higher unit cost than a run of 100 engines/year. You will need pretty much the same factory, with the same maintenance cost, power bills, and property taxes. That expensive tooling for welding/building core stages will sit around unused for most of the year. You will need most of the same specialized workforce, with pretty much the same number of higher paid engineers and administrative workers, and a few less lower wage technicians, floor workers and handling guys. You will also pay higher procurement prices for materials, parts and supplies.

I'll just repost this I guess: We still don't know if recovering a stage actually allows economically viable reusability. Reusing and refurbishing the first stage might allow some cost savings compared to building a new one, but there are many more factors involved in the cost of orbital launch. The manufacturing cost of the first stage is actually only a small part of the total cost of launching a rocket, maybe only 30% (optimistically). The rest of the cost is mainly the workforce, planning, infrastructure, logistics, R&D, transport, administrative overhead, etc... And there's transport, integration, launch services, and a lot of stuff that isn't recoverable (upper stage, fairing...). The payroll of the workforce is the biggest part of the launch cost, and reusability doesn't magically reduce the workforce. SpaceX is just about as lean as a launch provider can be and has already slashed prices as much as they could. Even with reusability, they will still need a factory and lots of engineers. Even if you need a few less people on the production lines to build less boosters, you need people to refurbish, prepare, and transport the recovered stage, which wasn't needed before. And this assumes that the first stage is actually free, which it isn't. It's designed to fly maybe 20 times, but not indefinitely. You could assume that by spreading the manufacturing cost over 20 flights reduces the cost per flight by 95% of the above-mentioned 30% figure, but it isn't even that simple. Disposable rockets (especially the Falcon 9) are actually designed to be (relatively) cheap, partly because they are produced in numbers. Manufacturing costs diminish with volume, meaning that as launch volume increases, the unit cost of each booster decreases.If you have 50 launches per year, with a disposable model, you need to mass produce 500 Merlin engines and 50 first stages. With 100% first stage reusability, the same factory has to build only 2.5 first stages and 72.5 engines. The result is that due to lower procurement volumes and higher fixed costs, those reusable stages are going to cost a lot more than the disposable ones. Enough to seriously cut into the reduction induced by reusing the stages in the first place. Instead of saving 95% on the manufacturing cost of the first stage, for the same amount of flights, the real cost reduction might only be 50%. So in the end, what sounded like a 95% (of 30%) reduction of launch cost might only turn out to be a 15% reduction, which has the potential to bring the cost of a Falcon 9 launch from $60 million down to $45 million. It's a nice perk to pass on to your customers, but it's not a game changer. Now, from the customer's point of view, the actual launch is only a small part of the total cost of a typical project. Maybe, again, 20%. The rest is the satellite itself (the biggest part of the budget), the ground stations, the insurance, and the actual operations. This means that in the grand scheme of things, the total saving that a customer can expect when they put a satellite in service is 15% of 20%, which is only 3%. On a $200 million comsat project, that's a whopping $6 million saving on their total expenses. Again, it's a nice saving, but it's not a revolution. Note: The above figures are educated guesses, but I believe the orders of magnitude are pretty close.

Do you read forums before posting in them ? We've been discussing this for a week. Do we really have to repost everything we've already said in your thread ?

Already discusses plenty of times, but all complex systems have a shelf life. For the same reason it's not practical to keep on running your car for 30 years, especially if it runs in an extreme environment. Parts get harder and more expensive to source and the whole thing grows obsolete. At one point, maintenance gets more expensive that buying a new one. Not yet, but by by 2024, some core components will be 30 years old, the solar panels will be producing much less power. ISS costs NASA $2 billion per year. After a while, you reach diminishing returns on the science that you are getting back out of those $2 billion. It's not designed to go any higher. The radiation shielding is not adequate for long duration stays at higher orbits. High orbit is also a riskier environment in terms of MMOD. Yes, a new station will almost certainly be cheaper to run. It will most likely be simpler and smaller and launched when it's needed. NASA could even rent smaller commercial stations when they need one.