Pedantic nit: they used slide rules back then.

Yeah, except they often referred to them as "computers". At least until the "electronic" variety became popular. So shush, you. :-P

Replacing titanium structure with aluminum, for example.

Interesting. I would have pointed to the heat shield, instead. Carbon-carbon was nearly invincible and was used for the leading edges of the space shuttle. But as a cost savings measure, they came up with that screwy tile system instead. It saved a ton on development, but it cost them later on.

And oh man, did it ever cost them.

By artificial gravity, I assume you mean using rotation to produce centrifugal force?

Correct. While we usually think of "artificial gravity" as some sort of sci-fi graviton thingy, von Braun used to term to describe the effect of rotating wheel in space.

That means that to get a full G of apparent gravity, you need a station with a radius of nearly 225 meters. Obviously, you could probably make do with less than a full G.

The original proposal by von Braun and Willy Ley was a 3-deck, rotating wheel with a diameter of 76 meters. Rotation would have been 3 RPM to provide artificial gravity of 1/3 earth normal. Since the effects of weightlessness were not known at the time, I believe von Braun intended the gravity to make the station more operationally efficient rather than meet the health needs of the crew.

I just don't see that being likely until we have a more efficient way than rockets to get material into space

You have to remember that they had the power of the Saturn V at their disposal. No weight was too heavy! No craft too large! And with the Nova drawings on the board, it was only a matter of time before mankind was the master of his solar system!

Of course, the fact that NASA was spending a fairly sizable chunk of the GDP on space exploration was lost on these engineers. There was not going to be a Nova, the Saturn V was seen as too expensive, and their ideas for a space station were simply too grand.

First, your numbers for the shuttle are flat out wrong. You forgot to account for the thrust from the SRBs. Second, your numbers for the SatV are missing. Third, the F-1 and the SSMEs are not comparable. The F-1 == SRB and the SSME == J2. Look them both up and you'll find that the shuttle is WAY more powerful on a per-engine basis.

Here are some corrected numbers:

Saturn V

Thrust: 34.02 MN
Mass: 3,038,500 kg
Thrust to weight ratio: 11.19:1

Shuttle

Thrust: 30.45MN
Mass: 2,030,000 kg
Thrust to weight ratio: 15:1

As you can see, the shuttle has 34% more power for its weight than the Saturn V. This is more than sufficient to accomplish the liftoff goals. The SRBs are actually shaped internally to REDUCE thrust during flight to prevent overstressing of the Shuttle hardware. The idea is to get up to Max-Q as quickly and smoothly as possible, then throttle back until the thickest part of the atmosphere is cleared.

There's a reason why the cosmonauts always like hitching a ride on the shuttle. As launch vehicles go, it's a really nice ride both on the way up and on the way down. ;-)

Compare apples to apples, please. The SSMEs are analogous to the J-2. (SSMEs are more powerful, BTW.) The F-1 analog is the SRB engines.

If you want to get off the ground in a hurry, the SRBs will happily flatten you to a pancake. In comparison, the Saturn V barely lumbered off the pad.

It's not ironic at all. NASA made an economic misstep by developing the Shuttle. The economics of launch vehicles favor the inline stack with smaller boosters for man-rated vehicles and larger boosters for cargo. Ne'er the two shall meet.

In absence of a clear need for a space station as a rendezvous point, taking a step backwards to more sophisticated capsules is how you get back on track for economic success.

What if Kennedy had set a lesser goal, such as orbiting the moon?

There's no tangible goal to take to the people there. What do you say? "Ha! We circled a man around the moon first!"? Doesn't hold much punch.

Do you remember who the first man was to orbit the earth? The vast majority of people wouldn't be able to answer. Some might answer "John Glenn". Only a small fraction of a percent of people would correctly answer Yuri Gagarin.

Do you remember who first set foot on the moon? Do you remember what his first words were? The fact that I don't have to answer either question speaks for itself.

8) SALT II would have long been abandoned and Earth would be surrounded by nuke armed stations.
9) No Cruise missiles. Why build a Mosquito when an Elephant would be cheaper.

Read up on the Revolt of the Admirals sometime. There's a good reason why we have cruise missiles and not nukes. It's not for want of orbital platforms.

4) No Space Shuttle. Rockets all the way. (Why mess with something that works)

We would have a space shuttle. It simply wouldn't be the "jack of all trades, master of none" we got.

The space shuttle was supposed to be a lightweight launch craft for transporting people to/from LEO where they could rendezvous with a space station and take a transport to a location like the moon. Economically, it made a lot of sense. It would have been fairly simple, cheap to operate, and with fewer disposable parts than the Saturn V. (Which basically throws away millions of pounds of hardware to return barely a few tons of mass. Very wasteful.)

So what went wrong?

Obviously, the same politics that killed the moon program. Nixon told NASA that they could have one launch vehicle, and the Saturn V was too expensive to be "it". Oh, and they needed to meet the military's needs for a launch vehicle as well, because the Titan rockets were also too expensive.

NASA got out their abacuses, ran some numbers, decided that the shuttle was key to a future space station, and committed to producing a super-shuttle that could be all things to all people. After all, they had the technology, right? Right?

Well, sort of. The engineers did an amazing job of producing the most sophisticated piece of space equipment ever designed. The power curves were incredible and the engines left the Saturn V in the dust. Only problem: It was a hellva lot of mass to send up and bring back, leaving little room for cargo. Worse yet, it was so complex that maintenance costs were through the roof. In the end, it would have been cheaper to continue operating the Saturn V with the economics of scale resulting in MORE cost reductions than the Shuttle ever realized!

What I'm getting at is that if we're going to play along with this dream-world where politics don't kill off programs, we'd have the Saturn V, the space shuttle, the space station (with artificial gravity!), and transport tugs originally envisioned by NASA. Because all those pieces have to fit together to make this mythical lunar base of 5,000 people possible.

Back here in reality, all those ideas were doomed from the beginning. The politicians only ever supported the space program to combat the USSR. By the 1970's, the Soviet Union had already collapsed. They were just coasting on momentum from there on out. That's why (save for a push by Regan to push the USSR to the brink of bankruptcy) the space program never recovered. There was no political need. And anyone who knows anything about politics knows that there has to be a need commiserate with size of the solution before there will be a large commitment. Hopes, dreams, and peaceful exploration ala Star Trek just don't cut it. :-(

No offense, but that's exactly the type of bullshit Microsoft wants you to believe. They've implemented some of the CSS stuff, but they're a LONG way from meeting a standard even as simple as FF1.5.

Call me when IE's DOM support leaves the DOM1 standard and moves on to the DECADE OLD DOM2 support. Then we'll talk.

Well, that explains the post. However, that's not 1337, that's LOLCAT; a derivative of texting language, itself a derivative of common IRC abbreviations.

1337-5p34| was developed to make the text hard to read/index and was "cool" for the hip 90's h4X0rz generation. i.e. Back when putting Zs on everything was kewl. :-P

I'd insert some completely random references that make fun of the movie Hackers, but that would be admitting far too much about my knowledge of the 90's computer culture. ;-)

My first reaction to the parent post is, "I'll bet he encoded a cool circuit design into the ASCII of his text!!! COOL!"

Then I realized he was posting from a cellphone. Probably the same one he had when he learned HDL "10 YEERS AGO". :-P

Now that Xilinx has released new chips, the old ones are pretty cheap.

The old ones were always cheap. I got my Spartan-3 kit about 5 years ago for $150. That's what the smallest Xilinx kit is selling for now.

As many people have pointed out, FPGAs are so cheap now that there are plenty of other boards for less. My problem with those boards is that you don't often get the comprehensive devkit you get from Xilinx. As a hobbyist getting started with FPGAs, I found the Spartan kit to be incredible at hand-holding you through the basics of getting into hardware design. Diving into logic theory took care of the rest.

The board layouts ended up being far more of a challenge. Without an instructor to guide you, getting the correct solutions for circuit voltages was a bit of a challenge. Not to mention selecting the right parts among the 11 billionty parts available. A little persistence can get you through it, though. I just wish I'd stop forgetting how a transistor works. Drives me nuts having to relearn it every time. (Probably because it still boggles me a bit. It makes perfect sense... and then it doesn't. Grrr.... :-P)

Trying to explain to a potential employer why you know JHDL and not verilog or VHDL is kind of depressing. JHDL's last release was 2 years ago and I'm not sure if it is an active project any more.

I think you miss the point. I'm not saying that he shouldn't learn VHDL and/or Verilog. Just that doing a bit of JHDL can give him some good experience with the way circuits lay out. He can actually see how, say, an adder circuit is constructed. Armed with that knowledge, he can more confidently write VHDL/Verilog code that will translate into the hardware he wants rather than some random circuitry that seems to do the right thing.

The lack of updates is disappointing, but not really a show-stopper. Even if the hardware JHDL supports falls into disuse, the simulation tools will still operate. And that's all one really needs for the learning experience. :-)

Hardware: I highly recommend the Spartan Starter Kits. They're dirt cheap, well supported by the industry, and come with a good toolkit. There's not much more you need to know other than you'll probably want a serial cable in addition to the JTAG cable the kit ships with.

I'll grant you that the fabric isn't very large by today's standards, but it's still enough space to learn about the hardware. By the time you outgrow the fabric, you should have a good idea of what size hardware you want. In fact, your next board may even be a custom design based on a bus like wishbone. ;-)

Software: The Xilinx stuff (pronounced "Zy-Links") comes with a full toolkit for VHDL/Verilog development including an IDE, place and route tools, and software to reconfigure the FPGA. It's all quite slick and easy for a beginner to use.

Language: The most common route taken by new hardware developers is to learn Verilog. They do this because it's similar to C and that makes them comfortable. THIS IS A BAD IDEA. I can't count how many hardware designers swear up a storm when they see a Verilog project with loops and other software constructs stuck into them. See, the comfort and familarity of C makes new hardware developers forget that the hardware is a fixed layout. There is no for loops or control logic as you think of it. It all ends up flattening to hardware. If you write regular software constructs, you'll end up with the least efficient circuit possible.

From this perspective, learning VHDL is better because you won't have that comfort and familiarity that might tempt you into creating poor circuits.

I actually recommend doing some JHDL code for a while. It's lower level than VHDL, but that's a good thing. You have to think about every wire connection and how it all links up. When you're done, you can easily step through your circuit and see how it plays out in hardware. Even better, you learn how to properly use software constructs like loops to create a large number of static hardware objects. This will make your code better without falling in the trap of trying to write software.

That's my 2 cents anyway. Good luck! :-)