Nibb31

Spaceship 2 can make it to the 100km mark. There isn't much doubt about it. They are just finally understanding that it isn't as easy as it looks. But I agree that VG cannot reach orbit with SS2 technology.

Did anyone ever claim that Humanity was smart?

The ultimate test for civilization will be to actually survive on Earth the next century or two. If we can get through the climate changes, while coping with our population growth, the rarification of easily available resources, and technological mutations, all at the same time and without losing our humanity, then we can do anything.

You are talking about a game that is a huge simplification of reality. We are talking about complex real-life industrialisation. There are multiple problems with your idea: - Most rocket stages are not refuelable, restartable or recoverable. They are designed to be disposable. They are not rated to survive more than a few minutes or hours in space. The paint tarnishes and peels off. Insulation materials flake off. Toxic residuals aggregate around the debris. One-go valves are gone. Pyros and ullage motors are spent. Any rubber or soft material will outgas and go brittle. Tanks deform when they lose pressure. Ablative material is destroyed. You would basically have to either redesign all your hardware to be reusable (with a large cost, complexity, and weight penalty) or plan for a total teardown-rebuild on orbit. This is the main reason why Space Shuttle ETs were never put to use. There were proposals to collect them on orbit and to build huge wet-tank space stations out of them. However, when you look closer at the idea, it's an inherantly bad idea. The insulation material was not space-rated and would have formed a cloud of flaking orange foam debris all around the tank, making the approach and docking hazardous. The modifications needed to stabilize and reuse the tanks would have used too much weight and reduced the payload fraction (docking rings, airlocks, internal fixtures, avionics, RCS...) and the orbital refurbishment work would have been too complicated. It was cheaper to build and launch dedicated space station modules. - The inspection and refurbishment work on individual components would be tremendous. Manned EVAs are long, dangerous, and require planning and training. You would need facilities for storage, repair, crew support. Look at the VAB or the SpaceX HIF at KSC. That's the sort of facility that is required to assemble and integrate a spacecraft with brand new components on the ground. Now imagine the complexity of constructing such a building on orbit, with support for the dozens of workers that are needed. Imagine the number of SLS flights such a building would need. - The sheer effort of getting to the debris, catching it, then taking it back to your orbital facility is going to use propellant. That propellant will need to be sent up. You will also need to send up spare parts, seals, paint, pyros, insulation... Everything that can't be recovered from a spent stage, including some large parts like engine nozzles. You will also need to send up the propellant needed to refuel that stage. That's 90% of the weight of a rocket stage. To do that, you'll need a tanker spacecraft, which is basically a rocket stage with it's own power, tug avionics, manoeuvering system, docking, and refueling capability. A tanker spacecraft is therefore going to be heavier than an actual equivalent rocket stage. So you refill your refurbished rocket stage and you are left with a spent tanker. Therefore, you might as well have sent up a brand new rocket stage and saved yourself the expense of refurbishing the old one and now refurbishing the tanker stage. Hardware is cheap. People are expensive. A worker on the ground costs thousands of times less than a worker in space. That's why we build stuff on the ground and launch it to space. The whole effort of paying billions to put people in space to refurbish hardware that costs a few millions is simply not worth it.

In KSP? How could you make it economical when there is no economical aspect to the game? Let me guess: all your debris is on an equatorial orbit at pretty much the same altitude, right? Unlike KSP, in real life, stuff is launched into all sorts of different inclinations and altitudes. To rendez-vous with each tiny piece of debris, an "orbital scrapper" would have to perform dozens of extremely costly manoeuvers. That's a hell of a lot of energy (and therefore heavy propellant) for a few tons of scrap metal, composite fairings, screws, covers, paint flakes... And once you have all that crap, what do you do with it? An orbital smeltering furnace or garbage recycling facility is not going to be cheap.

I wonder what puts you or your country on a moral high ground compared to different and much older cultures. The important thing isn't who accomplishes something. It's what Humanity accomplishes. Those countries are just as representative of Humanity as yours.

I wonder what makes you so optimistic? If you're lucky, you might get to see a manned Mars mission (although there are some 90 year old NASA retirees who have been waiting all their life to see it), but I doubt that a manned expedition to Saturn or Jupiter will happen in any of our lifetimes.

Robotic probes give us the biggest science return for the lowest effort. There is nothing that you can learn from a manned mission that you can't learn from a robotic mission (other than studying the human himself). It's just a matter of cost of designing and carrying the experiment there. For the foreseeable future, sending a robotic experiment will always be cheaper than sending a manned experiment, plus the man, plus the equipment to keep the man alive and sane and to bring him back when he's done. Robotic probes have the avantage of costing less, covering more ground, doing longer missions, and don't need to come back. You can potentially learn more from 20 rovers running for several years in different locations than from 1 manned mission for 3 months in a single spot. Humans have the advantage of quicker reaction times and faster understanding of their surroundings, but those are not major advantages when it comes to planetary science. There is no need for quick reaction or fast understanding because we are in no hurry. The point of using H2 is that it provides the highest amount of energy for the lowest volume. Volume means weight, but it also means tankage, which also means weight. Other fuels can only provide the same amount of energy with a higher energetic density, which means that your spacecraft is much heavier and requires even more propellant. The weight advantage of using an NTR is that you only need H2 and no oxydizer. If you are going to haul up H2O and the equipment to separate it into H2 and O2, then you lose the weight advantage of using a NTR in the first place.

You wouldn't see much, because a flyby would fly over the dark side of the planet. You'd see a sunset, 30 minutes of darkness, a sunrise, and you'd be on your way for another 10 months of travel... Not much point.

The SSMEs that are used by SLS are paid for and have been amortized over 30 years. In other words, they are free, and you can't get much cheaper than that. So there is no point in reusing them. The RS-25s that are supposed to go on the later SLS (if more than 3 ever fly, which I doubt) are designed to be cheaper than the old SSME design.

At the molecular level, everything is porous. H2 is the smallest molecule you can get, so it's very hard to prevent it from passing through another material as the gas expands. The only way to prevent it from expanding is to keep it liquid, which requires cryogenic cooling, which itself requires quite a lot power and cooling equipment. The other option is to use storable propellants such as RP-1 and hydrazine, but those have less Isp.

The only thing a VG joyride gives you is 5 minutes of weightlessness for $200000 and the ability to brag about having been above 100km. By comparison, a zero-G Airbus ride is $6000 for a similar duration (12x22 seconds). KSP is not reality. If science is what you want, then a balloon or a sounding rocket are cheaper. Cubesats offer longer duration experiments.

It would take a huge amount of dV to bring all those bits of debris to a common orbit for recycling and reuse. The energy balance between moving and recycling debris and launching new hardware is largely in favor of the latter and will remain so for a long time.

To launch in 2017, the design should have started years ago and construction should already be underway. All NASA funds are directed towards SLS and Orion at this point, so new ISS hardware is no go. The separation of the OPSEK modules has been Russia's plan since 2009 when it was announced. The only unknown is the date, but it has been assumed that it would be at the end of life of the ISS. Zarya would stay connected to the USOS. It is too tightly integrated with the rest of the ISS systems and it belongs to NASA, and additionally, it needs to stay attached because there is nowhere else for a deorbit Progress to dock. Zvezda is planned to be part of OPSEK, but it's old and nearing the end of its shelf-life. As a service module, it's old and noisy with outdated computer and life support systems, so it doesn't have much use as the main core of a 3rd generation space station and would have to be complimented pretty soon. Pirs, Poisk, and Rassvet are minor modules with no vital systems. The most essential part of OPSEK is therefore Nauka, but its launch has be postponed (yet again) until 2017 now. At any rate, disconnection of these modules can't happen overnight. It would require lots of EVA activity and load transfer planning, because there are quite a few power, fluid, and optical connections between the modules. This all requires very tight cooperation between the control centers, because you can't perform a Russian EVA while certain US experiments are underway or during manoeuvers and you can't disconnect systems on one side without reconfiguring other systems on the other side. Actually disconnecting the ROS from the USOS would require much more cooperation between the two countries than a status quo.

The whole point of a space shuttle is to bring back the SSMEs, which are the most expensive piece of the kit. If you are putting the engines on the core, then it simply doesn't make sense to have a reusable spacecraft. The Russians figured this out when Buran flew, which is why it was cancelled so early. It was simply too expensive to throw away the engines for each flight. The only reason they built Buran was because of American propaganda. They were afraid of the capabilities that it didn't have, but they needed to build one for themselves to find that out. The whole space shuttle paradigm simply doesn't make much sense at all. It was a great technological achievement and it was pretty, but it was a fundamentally flawed concept.

If all you're interested in is altitude, then yeah. But we all know here that space is about speed, not altitude. Altitude is pointless if you're just going to fall down again. You might as well just get into a stratospheric balloon and pull off a Red Bull stunt. If it's about experiencing weightlessness, then a Zero-G Airbus will get you more of it in one flight than VG and for much cheaper. X-15 was closest to a spacecraft because in addition to the altitude, it was actually exploring hypersonic boundaries, which is something that neither VG nor CS are capable of doing.

There are plans in place to properly deorbit the ISS into the pacific. Technically, it would be similar to how they currently reboost the station with a Progress, only in the opposite direction.

I know that this really qualifies as two parts and you only want to make one, but I would really really really like a Centaur stage configurable with one or two RL10 engines.

Note: Virgin had nothing to do with SS1. SS1 was an XPrize entrant by Scaled Composites. Virgin got involved much later. I don't have much interest in suborbital. It's really much closer to high-altitude ballooning or a parabolic Airbus ride than to orbital flight. To qualify as a spacecraft in my book, you need at least RCS and a TPS. The X-15 was more of a spacecraft than these things are.

The Russians plan to detach the new modules to reuse them on OPSEK. The old Zarya and Zvezda are so tightly knitted into the ISS systems and operations that they can't be detached or removed from the USOS without ditching the ISS itself. Oh, and Zarya actually belongs to the United States, so Russia can't take it back.

Yes, but to optimize the science return, your test bed would need a variable rotation rate and radius in order to observe the results with various parameters. As such, a giant ring doesn't make much sense. A "bolo" arrangement with a counterweight and a variable-length cable that you can spin down and spin up would make more sense. I agree that it makes sense as a science facility, but I don't think we will ever see any 2001-style giant orbital rings.

The Soviet N-1 explosion was estimated to be equivalent to 0.5 kT of TNT. The W54 nuclear warhead (used in the Davy Crocket nuclear bazooka or the AIM-26 air-to-air missile) ranged from 0.01 to 0.25kT of TNT. So yes, a Saturn V pad explosion would have been akin to a small yield nuclear device. There are some definite high-energy pad explosions in that video. Detonation or explosion, the payloads of those rockets get a heavy beating. If an NTR had been on top of a Saturn V in the same situation, I would be hard pressed to guarantee that the reactor would survive in one piece. Hazmat suits protect from alpha and beta radiation, not gamma rays which are the worst. The main reason they use hazmat suits is to avoid contamination of skin and clothes. They throw them away after use and they still have to limit exposure to gamma radiation. The only way to safely clean up in a radioactive environment is to rotate crews while limiting exposure time. That's why most of the Chernobyl liquidators survived by only working for a few minutes each on the site. They brought in thousands of men by train for only a few minutes work. It requires organization and lots of manpower and it's expensive. Some of the public's reaction to nuclear energy is irrational, but that's not a reason to blankly dismiss the real dangers and precautions that are necessary.

There are no spinning stations in reality. I don't see what the problem is to dock with a rotating station as long as you approach it on the axis and your roll matches to the roll of the station. For an observer on the spacecraft, the station would be stationary. However, I really don't see what the point of a large rotating station in LEO would be. The reason for building a facility in space would likely be to take advantage of microgravity, so you would design it specifically NOT to have gravity. Microgravity is what makes LEO appealing in the first place. If you want gravity, then there are plenty of places only a few hundred kilometers below where you have it. The only place you *might* need artificial gravity is on long duration interplanetary manned missions. However, even then it might not be a hard requirement because exercice and medication might be able to allow us to live indefinitely without gravity, and that is much easier than building large rotating space cruisers.

Any predictions of the future are going to be wildly wrong. http://thesoftanonymous.com/2012/08/19/imagining-the-year-2000-in-1900/ When I was a kid in the 1970's, we were told that by the year 2000 there would be colonies on Mars, we would all be commuting in flying cars, and our meals would be made of protein pills. Yet nobody ever predicted the Internet. However, I would suggest that in the next 20 or 30 years, the trend will go towards more virtualization and dematerialization. Both oil prices and technology will make physical travel obsolete. We would no longer need to physically go anywhere because we will be able to work and visit everything and everyone in the cloud. All this space malarkey will become obsolete because if we wanted to muck around in microgravity or go visit Saturn or Europa, we could just don our VR goggles (or plug our implants into the cloud) and go there by telepresence. There would be no point in sending humans to the Moon or anywhere else, because it will all be mapped in hi-resolution 3D and simulated in a computer.

You're partly right, but I don't think that cheap launches will increase demand. Even dividing prices by 10 will not cause launch demand to multiply by 10. Demand is created by purpose. There needs to be a reason to put stuff in space. Space needs new applications with a decent return on investment or at least some sort of incentive. The only economically viable space activity right now is comsats. Even if SpaceX was capable of cutting launch prices from $70 million to $7 million, it won't make new applications appear out of thin air.