Monday, May 23, 2011

What Might Have Been, Part II

Last time, we looked at some alternate post-Apollo scenarios, with an eye towards leveraging technology that the American taxpayer had already bought and paid for. After discarding more and longer Moon missions as expensive and impractical, we settled on basing the 1970s manned space program around two long-duration space habitats: the S-IVB based Dry Workshop, and the S-IVB based Wet Workshop.

Which begs the question: why are we doing this, anyway?

Mainly, if you want to tackle manned interplanetary spaceflight at some point, you have to address the question of whether or not a human being can stay alive, healthy, and sane after spending between 400 and 600 days in free-fall. There are a lot of ways to simulate the effects of free-fall on a human body. But there's only one way to find out for sure what free-fall does to you. And the key unanswered question pretty much to this day is still this -- can we deliver a crew to Mars that's fit to work once they get there? This series of missions is intended to answer that question.

Now that we've decided that we can afford to do this, and that this is something we actually want to do ... what does the schedule look like? More to the point, what kind of operational tempo can be kept up? As it turns out, the industrial plant at Kennedy Space Center was sized for a pretty heavy workload. There were two Saturn launch pads that were in the original plans, Pad 39C and Pad 39D, that were never actually built. The VAB could have kept all four busy. To get an idea of what kind of tempo KSC would have been capable of, let's look at the schedule that was maintained from December 1972 to December 1973:

December 6, 1972: Apollo 17 (Saturn V)
May 14, 1973: Skylab 1 (Saturn V)
May 25, 1973: Skylab 2 (Saturn IB)
July 28, 1973: Skylab 3 (Saturn IB)
November 16, 1973: Skylab 4 (Saturn IB)

So, in any one calendar year, KSC could support two Saturn V flights, and three Saturn IB flights. Which means that a single Saturn V flight plus three Saturn IB flights are easily within reach. That will form the basis of our alternative schedule.

Little would have been different in the flight schedule, at least up until February 1974, when Skylab 4 returned to Earth. The Wet Workshop R&D cycle would have been running in parallel with Skylab's, and would probably have had flight-ready hardware by early- to mid-1974. The Wet Workshop concept would require a few development test flights before it could be trusted with a long-duration mission. There were no such worries with Skylab, since it could be launched all in one lump. But with the Wet Workshop, first you had to prove that you could actually vent the liquid hydrogen tank and fill it with breathable air. Then, you had to prove that you could erect living quarters inside it, and use it. After that, it's a matter of qualifying the habitat for stays of three months, six months, then a year or longer. Possibly by the fifth flight, you could be ready for your most ambitious missions. With that in mind, let's take a look at what could happen by 1981.

* WWD-1 (Saturn IB): First development flight for the Wet Workshop. After orbital insertion, the crew performs a transposition and docking maneuver, and vents the LH2 tank. In principle, this should work, and then the crew pressurizes the tank with breathing air, and spends about a day fitting out the interior of the tank as living and working space. This first development mission lasts about 30 days. As a small bonus, after undocking from the workshop, the crew chases down and docks with Skylab, boosting it up into a higher orbit. After a 10-day stay at the old station, they return to Earth.
* Skylab B (Saturn V): Bet you didn't know that the Smithsonian exhibit was actually a flight-ready backup. Under this revised plan, the Air and Space museum loses one of its more interesting conversation pieces.
* Skylab B-1 (Saturn IB): First crew to occupy Skylab B. Three-month mission.
* Skylab B-2 (Saturn IB): Second crew to occupy Skylab B. Three-month mission. The intent, more or less, is to try to have Skylab B occupied continuously for as long as its consumables hold out. My guess is that Skylab B will have a design lifetime of two years, from mid-1974 to mid-1976.

* WWD-2 (Saturn V): This is the second development flight for the Wet Workshop. It involves both a more energetic trajectory, and a slightly more ambitious goal. This three-month mission inserts a S-IVB lab module into lunar orbit. Yes, it's actually possible to use a more-or-less stock Saturn V to put an empty S-IVB stage in orbit around the Moon. There was a McDonnell-Douglas design study in 1970 that worked out some of the details. Plus, I've flown this profile in Orbiter, so I know it's doable.
* Skylab B-3 (Saturn IB): Third crew to occupy Skylab B.
* Skylab B-4 (Saturn IB): Fourth crew to occupy Skylab B. It's more or less at this point that a Soyuz crew pulls alongside, docks, and spends about a week on board conducting joint experiments.
* Skylab B-5 (Saturn IB): Fifth crew to occupy Skylab B.

* WWD-3 (Saturn V): This is the third Wet Workshop development mission. It will be launched on a trajectory that will place the S-IVB lab module into an orbit 23,500 miles above the Earth, at an inclination of 28 degrees. This is almost, but not quite, like a geostationary satellite orbit. Instead of remaining stationary over the same point on Earth's surface, it will trace out a figure-8 between 28 degrees North and 28 degrees South. There was a proposal to fly the mission such that the figure-8 is anchored over Europe and Africa. Over the course of six months, seasonal change can be observed in both the Northern and Southern hemispheres. This is a tricky mark to hit from a piloting standpoint, but it's well within the Saturn V's capability.
* Skylab B-5 (Saturn IB): Sixth and last crew to occupy Skylab B.
* Skylab C (Saturn V): Third Dry Workshop station. This one is built with some resupply capability in mind. I expect this model will last for about three, maybe four years.
* Skylab C-1 (Saturn IB): First crew to occupy Skylab C.
* Skylab C-2 (Saturn IB): Second crew to occupy Skylab C.

* WWD-4 (Saturn V): Fourth Wet Workshop development flight. The mission profile is similar to WWD-3, but with a duration of at least one year. One possible wrinkle is that, instead of a fixed figure-8, the station is placed either slightly above or slightly below synchronous altitude. Then, instead of a perfectly-fixed figure-8, the figure-8 wanders eastward or westward with time. I found this out by accident, when I tried to nail a perfectly-fixed figure-8 and failed. There's some possible value in this: you get long loiter times over a region, but over the course of the whole mission you could cover the entire Earth, at least between 28 North and 28 South. With the successful conclusion of this mission, the Wet Workshop is considered proven for longer-duration missions.
* Skylab C-3 (Saturn IB): Third crew to occupy Skylab C.
* Skylab C-4 (Saturn IB): Fourth crew to occupy Skylab C.
* Skylab C-5 (Saturn IB): Fifth crew to occupy Skylab C.

* Skylab C-6 (Saturn IB): Sixth crew to occupy Skylab C.
* Skylab C-7 (Saturn IB): Seventh crew to occupy Skylab C.
* Skylab C-8 (Saturn IB): Eighth crew to occupy Skylab C.
* Manned Venus Flyby: And here's the payoff for having developed the Wet Workshop capability. As mentioned previously, you don't need to stay in Earth orbit exclusively. Once you've proven the technology, you can go strut your funky stuff across the Solar System ... within reason.

The dates are wildly optimistic, though ... starting from 1968, there's no way, no way at all, that this mission would be ready for launch by October 1973.

1977 and beyond:
* Skylab C-9, C-10, C-11, C-12: These are the last missions to Skylab C. Skylab D will probably fly in 1978, and will be used into the 1980s.
* Manned Mars Flyby: The other obvious target, accessible within a reasonable time frame.
* Manned Asteroid Flyby: This is contingent on finding a suitable target. Eros would be a good candidate. Or Icarus. It's just a matter of finding one or two that come close enough to make a flyby worthwhile.

And, The Downside...

Every option taken carries with it an opportunity cost. For example, having decided to build the Space Shuttle, we closed the door on getting the most out of our investment in the technology built for Project Apollo. This program is no exception. Having decided on a more ambitious manned program in the 1970s, the development work that would have led to the Shuttle is never accomplished. Which means that some of the Shuttle's unique advantages are not available in the 1980s. Such as:

No Hubble Space Telescope. Honestly, I could stop here. If you had to pick one single instrument that has revolutionized our knowledge of the Universe more than any other in the last 25 years, you'd have to pick Hubble, hands down. No Shuttle means no Hubble. That means no Hubble Deep Field. And none of the stunning images we've become accustomed to. Hubble was a key instrument in the observations of Supernova 1987A, and of the Shoemaker-Levy 9 impacts on Jupiter. And if that weren't enough all by itself...

Fewer Scientists In Space. The Shuttle can carry seven people at a time, only two of whom have to be pilots. Apollo could only carry three, two of whom were pilots. This, the fact that the Shuttle can carry up to five scientists at a time, made things like the Spacelab module possible. Now, after thirty years of Shuttle flights, I think it's probably safe to say that most of the people who've flown in space have been scientists or engineers; this would not have been the case otherwise.

So, as glorious as this alternate program would have been, I have to say that it's just as well that we didn't. Maybe this really is the best of all possible worlds.

Next in this series: Once upon a time, it was thought that Space Shuttles would fly fairly often, as many as fifty flights a year for the whole fleet. What would have to have happened to make that possible?

Saturday, May 14, 2011

What Might Have Been, Part I

We are currently counting down to the last flight of the Space Shuttle program. Just over thirty years ago, Columbia roared into the Florida sky for the first time; late this year or early next year, Atlantis will be the last to touch down on Runway 33.

Others will write about what the end of this program means. I may be one of them. But not today. Instead, I want to spend some time imagining what else might have been. Today, we're setting the Way-Back Machine to 1968, and take a quick peek at NASA's post-Apollo plans.

By 1968, it was fairly clear that they would probably take a swing at the first Moon landing sometime in 1969. Having hit the mark that President Kennedy set for them in 1961, they needed another goal to keep as many of their staff gainfully employed as possible. They had already been working on a set of post-Apollo options under the label Apollo Applications Program, but were also working on much more ambitious plans. What they presented to the Nixon Administration in 1969 was an ambitious, integrated program that included a reusable space shuttle, nuclear space tugs, a space station, and a manned mission to Mars by 1986.

That's not the might-have-been I want to look at. Going down that road requires you to imagine that Congress would be willing to fund NASA at its peak levels for another ten or fifteen years. That was never going to happen. But what might have happened is that a more modest program could have been proposed: one that built on technology that the American taxpayer had already bought and paid for. The question before us is, what could be done with a second production run of Saturn boosters and Apollo spacecraft? Further, what can be done with a fairly modest investment in additional spacecraft research and development?

Some of this ground had already been covered by the Apollo Applications Program design studies. For our purposes, though, only two pieces of AAP will be of interest to us: the Wet Workshop space station, and the Dry Workshop space station. While a lot of AAP's focus was on extending Apollo lunar technology towards building a semi-permanent or permanent base, the additional R&D funding to make that happen probably wouldn't be forthcoming. But there are practical considerations to contend with as well. As it turns out, three days is about as long as the A7L space suit could last in the lunar environment. By the end of the Apollo 17 moonwalks, the joints in Cernan's and Schmitt's suits were beginning to seize up from the moon dust. It just wasn't realistic to expect this suit to stand up to a full week of daily use, much less a month or more. This is a problem that could be cracked, given enough research focus; but the funding required to solve that problem just isn't forthcoming in the time frame we're talking about. So, as a practical consideration, we're going to restrict our consideration to things we can do without having to contend with dust.

This is the problem that AAP was faced with. With landings taken off the table, what's left? The only thing left is long-duration space flight. Which is why this alternative program centers on two different space station platforms: the Wet Workshop, and the Dry Workshop. Each one has its own strong points, and its own drawbacks.

The key advantage of the Dry Workshop is the reason why it's the one we actually built and flew in the Skylab program: it's a far better, and far more well-equipped research platform. More than one crew can use it. And you don't have to worry about packaging anything to withstand exposure to cryogenic propellants during launch. But the drawback to a Dry Workshop is that you can only put it in one place: in low orbit around Earth.

When you're talking about a Wet Workshop, the term "space station" may be a bit of a misnomer. You're using the liquid hydrogen tank of the spent S-IVB stage as living space for your crew, but the spent S-IVB stage isn't necessarily in low Earth orbit. There are any number of mission profiles. It's possible to put an empty S-IVB stage in orbit around the Moon, for example, giving the crew a place to stay while they spend a month or two doing detailed observations from lunar orbit. Or, it's possible to put an empty S-IVB stage in an inclined 24-hour period orbit, where it will trace out a figure-8 on a globe, giving you the opportunity to make observations of the same region of Earth over an extended period of time. The most ambitious mission profiles involve interplanetary fly-by trajectories to Mars or Venus. You can't carry as much equipment as you could with a Dry Workshop. But, the equipment can be more closely tailored to the specific mission at hand. It's a marvelously flexible concept.

We know that such a thing would have been possible. But would it have been affordable? Probably so: between 1968 and 1981, about $30 billion was spent on STS research and development. The marginal costs for a Saturn V launch were $185 million in 1969, and $55 million for a Saturn IB in 1972. A second production run of Saturn V boosters, 15 units, would run $2.775 billion; and a second production run of 30 Saturn IB boosters would run $1.650 billion. Skylab cost $2.2 billion, so we can guess that the wet workshop would cost at least as much. Call it $5 billion, for R&D for the first unit of each, and $500 million per unit thereafter. Fiscally, it looks doable.

Next time, we'll attempt to unpack the schedule, to see how much might have been done in the 1970s. And we'll also take a look at the downside: what we'd have given up on by going down this road.

Friday, May 13, 2011

Video Del Fuego, Part XLIV

or, Blogger Ate My Homework

Some sort of techniwockle confoogality at Blogger seems to have eaten the draft I was working on. So, until I figure out what to do about that, enjoy this track from They Might Be Giants.

Monday, May 02, 2011

Better Late Than Never

Well, I had intended to go on hiatus for a few weeks, but for obvious reasons, this won't wait.

Six years ago, give or take a few months, I wrote:

"To paraphrase Hunter S. Thompson, you can stand on a hill in eastern Afghanistan and look west, and with just the right kind of eyes, you can see the high-water mark where Islamofascism's wave crested, and fell back. In a weird way, I'm glad we didn't put paid to him at Tora Bora. I'm glad he's survived to witness these moments. He will die, eventually, with the searing knowledge of his utter DEFEAT burned indelibly into his synapses. Yes, this, too, is justice."

This was in the optimistic blush of a brief wave of elections and promises of elections that swept the Middle East in late 2004 and early 2005. I was, to say the least, overly optimistic. But I still agree with the broad outlines of what I had written.

Osama bin Laden is dead. He was killed not by an anonymous missile strike, but by a SEAL team that had been infiltrated into his compound. And while I'm happy he's no longer breathing our air, I'm just as happy that he saw Tahrir Square before he checked out. He died not in glory, but in defeat. Now, some quick observations.

One: As I often say when these things happen, there's an extent to which this changes nothing. Bin Laden was in direct operational control of Jack and Squat, and Jack left town a few years ago. He kept in touch by courier, which proved to be his downfall, but how much detailed planning can you really do that way? We still have the Taliban to deal with in Afghanistan, and Al-Qaeda in the Arabian Peninsula to deal with, led by Anwar al-Amriki in Yemen. Or so it's thought. So, the plate's still pretty full.

Two: On the other hand, this does change a lot. Bin Laden was an important symbol of the movement. He was the one man that everyone in the movement looked up to and respected. He was, unquestionably, The Big Cheese. And don't forget the detritus that was taken from his compound upon his demise. Al-Qaeda in Iraq pretty much folded up like a cheap tent once Abu Musab al-Zarqawi got his ticket punched. Everyone bin Laden was in direct contact with has to be sweating bullets right about now. If they go to ground now they might be able to break contact and stay a step ahead of pursuit. Or, they might not. They won't know until a SEAL team shows up at the door yelling "CANDYGRAM!"

Three: And that's also an important point, all by itself. Ten years ago, the CIA didn't speak to the special-ops community well, if they even spoke at all. Now, they work together fairly seamlessly. It's taken a decade to do it, but the CIA has returned to its OSS roots, and rediscovered the old-school arts of human intelligence. And they've also added a few new wrinkles, such as teaching commandos police forensics techniques. These things take time to work, when they can work at all. It may take years to finally get that last piece of the puzzle. But a sufficiently patient and dedicated investigator can crack the coldest of cold cases, if they get the right resources to do so.

Four: Pakistan has some 'splainin' to do. Like, just how was he able to hide in plain sight like this, just outside of their capital city? Mind you, the Pakistani ambassador had a good point. Two words: Whitey Bulger. That said, the point still stands that Pakistan's intelligence agency basically set up the Taliban, back in the day. There's been a long-standing suspicion that the ISI had been tipping off Taliban and Al-Qaeda targets when raids had been planned. They weren't trusted with the information on this raid until it had already happened. There's a serious conversation that has to happen between our governments, and it ought to happen soon.

Five: While this doesn't destroy Al-Qaeda, or even come close to it, Al-Qaeda is essentially irrelevant. The sweeping changes seen this spring in the Arab world have basically left them behind. You see, for all his faults, George Bush got one thing right: they key problem in the Arab world could be traced to a lack of self-determination. Al-Qaeda's answer to that was to re-institute the Caliphate, under a strict system of Islamic law. But this spring's demonstrators want no part of that program. They want democratic government, laws that mean something, and protection for their civil rights. The upcoming Arab generation is grabbing hold of self-determination with both hands, and are winning for themselves the honor and the self-respect that come with it. They have no need of Al-Qaeda. It probably won't die, but it'll persist more as a criminal syndicate than as a political movement.

Six: This ought to put paid to the ridiculous notion that President Barack Obama is some sort of pacifist, who won't even use military action as a last resort. It also ought to put paid to the equally ridiculous notion that President Obama is a closet Muslim that will shy from spilling a fellow-traveler's blood. And while Trump was having a fit about Obama's birth certificate, Obama was busily planning a surprise bullet fiesta for Osama bin Laden. This man will take care of business when it's necessary. You doubt this at your peril.

Seven: It's far too early to tell where this all ends up. I do believe that a wave of change is sweeping that part of the world, and that there's not a single government over there that will escape unscathed. Not all of the movements will succeed. Some will fail to fulfill their early promise. Some of them, maybe even most, will succeed at least partially. And a few will succeed brilliantly. And the world will be a better, safer place for it. There's still some excitement to come, but at least there's more hope in the air than there's been in many, many years.

Eight: And lastly, what effect will this have on next year's elections? Probably not much. A year and a half is an eternity in politics, and besides, the economic conditions next summer will have a far more profound effect. What this unquestionably does is give Obama one more positive point to hit regarding his record in office. And possibly most telling, it's a foreign policy point. It's ludicrous now to campaign against him as being soft on terrorism. Not that it'll stop them from trying. I'm just saying, it won't work. If next year is as incumbent-friendly as I'm beginning to suspect, it'll just make them look pitiful.

OK, now back to my regularly-scheduled vacation. See y'all in two weeks, give or take.