He was also a Navy fighter pilot who served in combat during the Korean War. We should not forget his honorable service in the military.

        drbuzz0 said:

Except then you can have multiple launchers any one of which can cost the mission if it fails.

What if you need to launch a lander, an earth-departure stage and a habitat?

Your launch of the earth departure stage goes well. The lander goes well. Then the habitat blows up.

Now what?

Just leave the other two up there in a parking orbit for a few years while you build a new habitat and launch it.

No, launch your backup. And same for the rest of your comments. You’re really not getting this, and I don’t have the time to educate you further; there are plenty of online resources if you wish to leave your heavy lift tunnel view…

        cthulhu said:

With all due respect, you’re wrong on all counts in the section of your reply that I’m quoting here.

(1) You do NOT need heavy lift to go beyond earth orbit or put big things into orbit. In fact, heavy lift is a detriment to those things, not an enabler. Think about the terrible risk you’re taking by doing a monolithic launch on a heavy lifter: something goes wrong, you’ve lost everything. This is not a sane engineering tradeoff. It is well known that the way to make something reliable is to build lots of them and operate them regularly: this is true of cars, airplanes, computers, televisions, nuclear reactors, and rockets. Some things you just can’t find out without operating the system. There are learning curve effects on launch, recovery, and on-orbit operations that dramatically reduce the cost as well. A heavy lifter is going to be much more expensive than a moderate lifter, and consequently its flight rate will be much less – nobody’s going to pay to launch on the heavy lifter unless they really need it.

Except then you can have multiple launchers any one of which can cost the mission if it fails.

What if you need to launch a lander, an earth-departure stage and a habitat?

Your launch of the earth departure stage goes well. The lander goes well. Then the habitat blows up. Now what? Just leave the other two up there in a parking orbit for a few years while you build a new habitat and launch it. In that time, the fuel will have boiled off the EDS, so it will be useless. The mission is basically lost.

For stuff like manned mars missions with a lot of capabilities we may well need to launch 300 tonnes into orbit. Better to do that in three launches than ten. Much less complex.

You stated that yourself. If the flight rate is dramatically less, then its reliability will be as well. This is inescapable engineering fact.

Again, unnecessary complexity. A lot of launches. Each rocket with its own expensive guidance system, thrust vectoring, engines etc etc etc.

A single Saturn-V was modified to place a whole functional space station in orbit. Not a small, incapable space station either. One shot and Skylab was in orbit complete with 283 cubic meters of pressurized, habitable volume. In fact, they cut corners and saved money by sacrificing weight. Rather than a water reuse system, they just send up many tons of water. Rather than resupply flights for oxygen, they sent up a huge amount of oxygen on the initial flight.

Skylab weighed 76 tonnes. Had they built a space station from scratch (rather than using am S-IVB tank) and made it lighter, it could have been bigger still. Two Saturn-V launches could have put a massive space station in orbit.

Skylab was 2.2 billion dollars for its entire program. That would be like 12 billion today.

The modular approach that uses many small modules is much much much more expensive.

The ISS has about three times the habitable volume of Skylab. It weighs 370 tonnes.

It took over one hundred billion dollars to build it. That includes a whopping 32 shuttle flights, most of them with assembly of major components. More flights were required by unmanned spacecraft. And this is considering the program is based on programs and hardware that started construction in the early 80’s.

NASA worked on modules for a space station from about 1981, while Russia worked on Mir-2 modules until they canceled the US space station and adapted them for the International Space Station which finally started being launched in 1998. It is still not complete.

Big launches = fewer flights. To build a space station, you get a fully functional facility right off the bat and you can build a huge one in a relatively short period of time. No need to wait decades and spend hundreds of billions to get a mediocre space station.

        drbuzz0 said:

Then as far as SLS: Well, we need an ultra-heavy launch system. That seems clear. If you want to go beyond earth orbit and also be able to have things like next generation space stations and telescopes, you need the ability to put more than 100 tonnes into space in one shot.

Multiple launches gets cumbersome, especially if you have to put in orbit 200 tonnes or more.

With all due respect, you’re wrong on all counts in the section of your reply that I’m quoting here.

(1) You do NOT need heavy lift to go beyond earth orbit or put big things into orbit. In fact, heavy lift is a detriment to those things, not an enabler. Think about the terrible risk you’re taking by doing a monolithic launch on a heavy lifter: something goes wrong, you’ve lost everything. This is not a sane engineering tradeoff. It is well known that the way to make something reliable is to build lots of them and operate them regularly: this is true of cars, airplanes, computers, televisions, nuclear reactors, and rockets. Some things you just can’t find out without operating the system. There are learning curve effects on launch, recovery, and on-orbit operations that dramatically reduce the cost as well. A heavy lifter is going to be much more expensive than a moderate lifter, and consequently its flight rate will be much less – nobody’s going to pay to launch on the heavy lifter unless they really need it. You stated that yourself. If the flight rate is dramatically less, then its reliability will be as well. This is inescapable engineering fact.

(2) So, if you don’t build a heavy lifter, what do you do? Modular design and on-orbit assembly is the way to go here, and this is a place where NASA can really lead the way. There is a lot of work needed to prove out these approaches in a full-scale engineering sense; NASA can jump start this inevitable path and work out enough of the nitty-gritty details so that the commercial sector can take over. In my thesis, this is NASA’s true role in space exploration.

(3) So how do you get beyond earth orbit? You develop on-orbit fuel depots. Again, NASA can and should do the work to prove out this technology at full scale; once you can refuel in LEO, you can go anywhere in a steppingstone fashion.

This trinity of technologies – high flight rate, highly reliable medium lift; payload modular design and on-orbit assembly; and on-orbit fuel depots – will create a reliable, cost-effective infrastructure for continued space exploration and commercialization, with zero need for an expensive, low flight rate, white elephant heavy lifter.

And there’s no real reason to pine after the Saturn launchers, or really any of the Apollo infrastructure: they were all economically unsustainable; the whole lunar orbit rendezvous architecture of Apollo, requiring the heavy-lift Saturn launcher, was chosen purely for time reasons – it was clear that the earth orbit rendezvous concept, while much more parsimonious with resources than LOR, would take significantly more time to develop, and as such could not meet the “before this decade is out” requirement.

        cthulhu said:

That doesn’t mean that we need to spend tons of the people’s money on it though. Amazingly enough, the current administration more-or-less has the right idea: set up ways for NASA to do the hard technology development, but leave the more mature technologies (like delivering humans and cargo to LEO) to the private sector. It kills me to see ostensibly free-market politicians embracing huge government programs like the Senate Launch System.

The current administration has some things right. One thing they are missing is giving a nasa a good clear-cut path and mission. What is NASA supposed to be shooting for? It’s very hazy and not well defined.

Contractors have always built the hardware for the space program. One of the problems we have now is that we have good privately built spacecraft for ISS resupply, but not much else. NASA has been dragging its feet on taking it further and seems to be unsure what path to take.

Then as far as SLS: Well, we need an ultra-heavy launch system. That seems clear. If you want to go beyond earth orbit and also be able to have things like next generation space stations and telescopes, you need the ability to put more than 100 tonnes into space in one shot. Multiple launches gets cumbersome, especially if you have to put in orbit 200 tonnes or more.

In hindsight, we really should never have abandoned the Saturn line of launch vehicles. But oh well, you can’t go back.

NASA will likely need to shoulder the burden for that, because there’s such limited commercial potential for that. Nobody has a 100 tonne communications satellite.

SLS looks horrible, however. It uses a limited number of very expensive engines to build a very expensive launch system that has limited capacity over existing systems and will be flying half-empty most of the time anyway.

        drbuzz0 said:

I feel like if you imposed today’s social and political climate on the Apollo missions, they would not have happened.

You’d have people protesting that the Saturn-V was a frivolous use of energy and petroleum and others protesting that the missions carried plutonium-238 powered RTG’s. Others would say that building such a large rocket was sabre-rattling since some of the technology could be used for ICBM’s.

Well, there were protests about the Apollo program; lots of community organizers (among others) decried spending money on space when people were hungry back on earth. And public support cooled very rapidly after Apollo 11. The vast majority of people don’t get why manned space exploration is important – it’s not the science, it’s (I hate to use the term, but it fits perfectly) manifest destiny. “Because it’s there.”

That doesn’t mean that we need to spend tons of the people’s money on it though. Amazingly enough, the current administration more-or-less has the right idea: set up ways for NASA to do the hard technology development, but leave the more mature technologies (like delivering humans and cargo to LEO) to the private sector. It kills me to see ostensibly free-market politicians embracing huge government programs like the Senate Launch System.

        I’mnotreallyhere said:

You know, I’m not so down on the space program since the Apollo missions.

Skylab and Mir paved the way for the ISS, allowing oodles of reasearch to be done on all sorts of topics.

The Hubble space telescope has taught us all sorts of things we never really knew about the universe.

I see your point. One thing that is important to remember is that as far as NASA is run, the manned space program and unmanned space programs are different sides of the coin and are funded and administered separately.

I suppose my big problem is with the manned program. I believe manned spaceflight is important and must continue, not simply for the scientific data it returns (which arguably can often be done by robotic missions) but because it is part of mankind branching out.

It’s a long process. First we get to the point where we can reliably send humans to orbit. Then to deeper space missions. Then we have outposts on the moon and mars. After that comes more contained communities and finally full-blown colonization.

We will not live to see colonies of humans who live their lives on mars, but we might see outposts and research stations. That is a very big step toward humanity moving from a single-planet species to a fully space-faring species and perhaps, in the distant future, even going beyond the solar system.

One of the problems with NASA is what their mission has been since Apollo.

After the Apollo program the main focus was on the Space Shuttle. The idea behind the Shuttle was to break free of the expensive ELV launch systems used to send the first missions into space. The Shuttle was supposed to be “cheap, routine” spaceflight. A reusable spacecraft that could do quick turn-around, reasonably cheap runs to a space station. It would never be as cheap as an airliner, but perhaps on par with the SR-71 or something. Something you could run without each launch being a major event.

This was a very worthy goal and would have changed spaceflight. It would have also opened up the moon and more distant exploration, since getting to orbit is half the problem. If you look at the missions NASA profiled in the late 1960’s and early 1970’s, they were very impressive. A shuttle to bring humans to a space station as a way-point to the moon and beyond. Space-based tugs with nuclear rockets would take humans even further. Think about the mission shown in “2001 A Space Odyssey,” where an orbital space plane takes passengers to a rotating space station where they board a second spacecraft to go to the moon.

So what happened?

The Shuttle did not even remotely live up to what it should and could have been. First, the government made the requirement that it be the ONLY NASA space vehicle. This was horrible. It’s difficult enough to build a fully reusable spacecraft, but forcing it to be a heavy life vehicle killed most of the potential. It’s like driving a dump truck to the supermarket.

The budget was cut repeatedly for the design and it was decided that it had to make maximum use of Apollo-era infrastructure. The Shuttle was transformed from a two-stage, fully reusable winged spacecraft to carry humans into a weird hybrid of a side-straddling heavy life space plane strapped to a massive tank and SRB’s.

The result: The shuttle was more expensive than capsules. It had some amazing capabilities for LEO operation, but it lacked the ability to take humans any further. Cargo capacity was about as good as a big ELV, but more expensive. It had a complex TPS and no launch escape system. It proved to have about a 1-2% chance of loss of vehicle and crew.

The Shuttle was only somewhat reusable. The Orbiter could be reused, but it had to be completely torn down and refurbished. All the systems had to be removed and rebuilt. The tiles all had to be inspected and many re-set. The engines needed to be removed and refurbished. Even the windows sometimes needed to be re-ground.

The SRB’s are only somewhat reusable. After recovery the thrust vector control system is only good for one mission. The electronics and actuators need to be replaced. Really, all that is salvageable is the big metal tubes that are re-packed with solid propellant.

The external tank is a complete loss. Granted it’s “just a big tank.” However, that big tank is made of a high tech lithium-aluminum alloy, precision manufactured and packed with sensors and special plumbing. The tank alone is one hundred million dollars and thrown away with each mission.

After it became obvious that the Shuttle had not fulfilled its mission, NASA continued to focus on the whole “Cheap, safe, routine” access thing. Again, a worthy goal, but they never had a good solid program they focused on.

First it was the NASP, which was supposed to be the next thing throughout the 80’s but canceled in the early 1990’s. They spent some time and effort on the DC-X/Delta Clipper concept before shelving that. Then came Venturestar, which received a massive investment, before it was completely disbanded, after going over budget and after a tank test failed (no, they didn’t even give it a second try with a different tank design). The hardware and facilities for Venturestar were sold off as surplus at a huge loss.

What NASA needs is a coherent plan and they need to stick to it. They need the budget necessary to achieve it. My feeling is either do it properly or don’t do it at all, but don’t do a half-assed job of it.

I tend to think that government research dollars are best spent on “Pure science” as opposed to “applied science.” Private industry is good at R&D with the aim of providing a viable product, such as a drug, transportation method or power source. But there’s no money in basic research for the sake of curiosity – such as particle physics, space exploration and such.

Pure science does yield data that can be used to produce usable products, but it’s hard to predict what kind of products will develop from it or how long it will take to get that data or how much that data will be worth. Also, the data is often very general and therefore can’t be patented.

Private for-profit enterprise therefore does not usually build sophisticated space telescopes or facilities aimed at pure research.