Chair Force Engineer

Thursday, December 21, 2006

Frozen Desert

The fairly heavy snows which first hit Albuquerque late on Tuesday essentially shut down the city on Wednesday. Even Kirtland Air Force Base was closed, despite the military's need to fight any foe in any weather (then again, this is the Chair Force where most of its people wage war from a seat.)

Albuquerque was caught totally unprepared for a moderate snowstorm. The roads have been neither salted nor paved; a sprinking of grit on the major roads was the only precaution. The interstates were closed and many businesses closed early.

I grew up near Chicago, and I'd have to call Albuquerque's reaction to this snowstorm pathetic. We'd normally get at least one good storm (12" or more accumulation) per winter in the Chicago area, but there would at least be plows and salt trucks to make things driveable. Schoolkids would only miss about a day of school in an average year, despite the volume of snow that we'd get.

Maybe I expect too much from desert-dwellers in adapting to moderate snow. Granted, I was taken aback by it too, but the local government agencies should always prepare for these weather conditions.

If it's any consolation, the snow-covered mountains are beautiful this time of year. Wish you could be here to see them.

Friday, December 15, 2006

Centaur Stage

Lockheed Martin has publicly talked about a wider Centaur upper stage for its Atlas V rockets. The new Centaur would be scaled up to match the 5.4 meter diameter of the Contraves payload fairing on some Atlas V variants. The bigger Centaur could carry six times the propellant mass of the original Centaur on the Atlas V, and have as many as six RL-10 engines (much like the Saturn I first stage.)

Jon Goff has been somewhat bullish about the idea. The benefit is that payloads that might have needed one or two SRB's can use the bigger upper stage instead. This is significant, in my opinion, because SRB's are a leading cause of failure for rockets in this class. The obvious drawback is that development of the new stage will cost a significant amount of money. With the Atlas V currently not viable in a commercial sense, there appears to be little motivation for pursuing the idea further.

As an interim step, I propose that Lockheed Martin adapt the Centaur G, used on some Titan IV missions, for use on the Atlas V. While the 4.33 meter-wide Centaur G would not have the benefits offered by the 5.4-meter Centaur, it wouldn't cost a lot to develop, either. It wouldn't face any aerodynamic loads because it's probably small enough to fit inside the 5.4 meter fairing instead of supporting the fairing's weight (it would assume the same position that the current Centaur fills inside the fairing.)

Jon also suggests cutting costs by using the Centaur on both the Atlas V and Delta IV. The Centaur's structure is lighter than the Delta IV upper stage. This is because the Centaur uses a partially pressure-stabilized structure (the "balloon tank" concept) like the old Atlas did. In fact, Centaur was originally proposed by Convair as a natural extension of what they had developed on the Atlas program, except that hydrogen was used instead of kerosene (this was a radical idea for the time, as hydrogen was not in widespread use.)

I would assume that the Delta IV would require a wide-bodied Centaur to perform its standard missions. However, the current Single-Engine Centaur on top of a Delta IV first stage could be a suitable replacement for the Delta II (which will soon be phased out, even though there's really nothing in the US fleet that meets the same requirements.)

The Centaur series is one of the oldest families of upper stages that's still being produced. Even so, there's plenty of life left in the design. The balloon-tank concept and RL-10 series engines continue to serve as good solutions for a unique design challenge. Future versions of Centaur may even fill the role that NASA has carved out for its proprietary "Earth Departure Stage" design. That will be the subject of an upcoming post.

Sunday, December 10, 2006

Eyes on the Prize

Earlier this week, NASA made it clear that the ultimate objective of its moon program was a permanently-manned base near the moon's south pole. In my eyes, this appears to be a sorely needed sense of direction behind the national moon effort.

It's worth asking the question, "What was the ultimate goal of Apollo?" The best answer to that question is "to beat the Russkies." There were some scientific secondary goals, but national pride (or, as Tom Wolfe claimed, "single combat" in the mold of David and Goliath) was the ultimate motivator. This explains why Apollo was allowed to fizzle out. We beat the Russkies, rubbed it in their faces with five more landings, and then quit--a sad end to a glorious endeavour.

Michael Griffin has said many times that the goal of America's national space program is a sustained human presence that brings human life to other worlds. By targeting all of NASA's manned moon missions towards a south pole base, all of our efforts will be applied towards that single goal, and (hopefully) nothing will go to waste.

Conspicuously absent from the NASA announcement is a strategy for transferring control of that lunar base to a private entity. Such a move will only take place if a commercial rationale for manned moon missions can be found. The plan for this transfer will grow more important as the moon program moves along. Without it, NASA will be forced to tend a moon base and have its hands tied in terms of initiating missions to Mars or asteroids. NASA did say that this base would be international in nature; perhaps NASA will rely on international partners to carry the burden of a moon base (akin to what will soon happen to the space station.)

How's this for a twist of fate: what if Russia is forced to sustain the moon base America started, by launching Ares rockets from pads originally designed for the similar Energia rocket?

Thursday, December 07, 2006

Virginia is for Haters

The imminent launch of TacSat-2 aboard a Minotaur rocket has many Virginians (and plenty of people from Maryland as well) excited about their state's future in the space launch business. Their hope is that NASA's Wallops Island facility will host a boom in the space sector, and pour millions of dollars into the local economies.

Politically, this is a good thing. And it would seem that politics is the only thing going for Wallops, at least as far as orbital missions are concerned. As I've noted before, Wallops is less than ideal for orbital launches. It can hit far fewer inclinations than Cape Canaveral (due in part to overflight restrictions on Brazil and Bermuda) and provides less of the earth's rotational velocity to a rocket traveling on an easterly trajectory.

With all of these things working against Wallops, why would Orbital build a brand-new Minotaur pad there (especially when Minuteman pads at Cape Canaveral could have been modified for the task?) It's a good question for a certain DoD agency that wanted to use the Minotaur for a future mission requiring an easterly launch, and it's a good question for the Virginia and Maryland congressional delegations. For Orbital Sciences, having a launch pad near their offices in Dulles, Virginia is a definite plus.

I really can't say if the current slate of Minotaur missions (TacSat-2 and two more DoD launches in 2007) is indicative of the future for Wallops. My guess is that it's not a sign of real prosperity, as Minotaur has little chance of commercial viability apart from DoD launches. And for all we know, Falcon I might have the bugs ironed out in time to replace the Minotaur for future DoD missions in the same class. Falcon I will launch from Omelek Island, which is great for all the reasons that Wallops is bad, but it's a bitch logistically since it's so far from the continental US (the one area where Wallops is great.)

Maybe it's the fact that I spent four of the best years of my life in Central Florida, but I'll take Cape Canaveral for my east-coast launch needs anyday.

Wednesday, December 06, 2006


It appears that NASA is giving up on the Mars Global Surveyor, which fell silent over a month ago due to a failure in the solar array joint. MGS didn't fall victim to the "Great Galactic Ghoul." It simply wore out after a ten-year mission that represented ten of the most productive years for exploring Mars and unlocking its mysteries.

Even though the mission is likely over, the legacy of MGS is only now starting to become clear. Today it was announced that MGS images seem to show liquid water on the surface of Mars. If confirmed, this discovery turns our ideas about Mars completely upside-down. Since the Mariner 4 flyby of Mars, scientists thought of the planet as static, dead, and fairly dull. But then we started to learn that the Martian poles were predominantly made of water ice. And then there were tantalyzing hints of methane in the atmosphere that could indicate some form of extant life.

NASA's philosophy towards Mars has been to "follow the water." The channels that criss-cross the Martian surface, plus minerals in the soil discovered by the Opportunity rover, indicate that the planet had been wet at one time. Mars Odyssey gave us tantalyzing hints that water lie just under the surface of much of the planet. But the newly-released MGS photos lead us to believe that this underground water may seep out of the ground and exist as a liquid under certain temperature and pressure conditions.

The view of Mars is continually evolving, and the recent trend is that Mars is less hostile towards sustaining life than we once thought. What does that mean for the discovery of life on Mars in the past, and the possibility of Martian microbes in the present? What does it mean for the potential of restoring life to Mars, by way of human colonization and terraforming? These are fascinating questions that will be pondered for centuries to come. We will always remember that MGS was the very start of it--launching as NASA resumed its exploration of the red planet, and ending as NASA finally found the water that will be the lifeblood of the humans who will live on Mars.

Monday, December 04, 2006

A Review of "The Space Review"

I really enjoyed this week's installment of The Space Review. While I usually do enjoy reading it every Monday, this week was exceptionally good. It made me want to comment on two of the more stimulating articles.

Wayne Eleazer talks about how the Delta IV and Atlas V were developed and why we're at this point today. He points out that the Air Force tried to envelope the needs of the commercial sector when the EELV requirements were initially drafted. The service's failure to accurately predict the needs of commercial vendors led to the adoption of solid rocket boosters for both rockets.

I would consider myself to have a libertarian perspective on life; I shun big government (yes, the big bloated bureaucracy that cuts my paychecks) and I embrace free-market capitalism. My approach to EELV would have been to let the industry develop the rocket based on their own commercial projections, and to treat the government as just another customer. Of course, national security demands that a launcher be built regardless of commercial projections. To solve the problem, I would have the government guarantee a certain number of launches to the first vendor that could meet the government's requirements. That's similar to how Falcon I was devloped and the Defense Department's current contract with SpaceX.

Eric Hedman (who has previously written on an EELV-based architecture for lunar return) makes valid points regarding the viability (or lack thereof) of the Ares rockets and the alternatives. He shows some bias (as do I) towards Direct Launcher. I especially like this paragraph:

If NASA management won’t seriously look at this proposal, I’m asking Congress to do their job as the “board of directors” of our government. This decision is crucial for the future of the US manned space program. Don’t let the design be finalized before know that a potentially much better option wasn’t considered. If this proposal is dismissed without serious consideration, NASA may lose the support and confidence of the many space enthusiasts that pester their representatives in Congress who, in turn, help keep NASA funded. I can’t say if the Direct Launch concept is the best ultimate choice, but I do think the concept need a fair hearing before irreversible changes to NASA’s infrastructure are started.

I don't believe that Direct Launcher is being given a fair hearing within NASA, because Michael Griffin is irrationally enamored with The Shaft. At least the NASA senior management gave lunar orbit rendezvous a fair hearing back in 1962 (back when it was a fringe idea,) and their open-minded approach allowed Apollo to get to the moon by 1969.

Mark Whittington tries to rebut Eric Hedman's call for congressional scrutiny, and while I share his concerns about congressmen (who largely aren't savvy on technical matters) making engineering decisions for NASA, I also believe in the congress's constitutional power of the purse, and their moral obligation to American taxpayers to ensure that tax dollars are wisely spent. We can only pray that the legislative aides will do their homework about the competing moon plans, and make compelling cases to their bosses to approve the best of those plans.

Saturday, December 02, 2006

Independent Thought Alarm!

Jon Goff has run the numbers and showed that a two-man moon mission is both feasible and realistic. Out-of-the-box thinking will certainly help us get to the moon (as it did when maverick engineers proposed Lunar Orbit Rendezvous instead of Direct Landing or Earth Orbit Rendezvous for Apollo.) An EELV-based approach was being considered during the O'Keefe days, and might have been able to see the light of day had Sean O'Keefe and Admiral Steidle not packed their bags and skipped town. But Michael Griffin and his band of Zubrinistas are opposed to anything that runs counter to The Case for Mars. Project Constellation is now consigned to the Stick rocket, mammoth heavy-lift rockets that only exist on paper, and... congressional cancellation?

Jon is right to challenge the assumption that we need to put four men on the moon for seven days (a requirement which essentially sizes the entire architecture.) This is twice the size of Apollo's Lunar Module crew, and they stay for about three times as long as Apollo did. If the Orion capsule can operate unmanned in lunar orbit as NASA wants, a two-man moon mission could achieve all of Apollo's objectives. It should be noted, though, that Project Constellation should surpass the achievements of Apollo rather than merely recapture the glory of days past. Still, crew size and duration of the surface mission should be opened to impassioned debate rather than an arbitrary, politically-imposed solution.

NASA originally specified a crew of three for Apollo with a logical reason in mind: a crew of three allows the crew to operate for 24 hours a day, with one crew member taking an 8-hour rest at all times of day. I believe that the Orion Lunar Module should be sized for a similar contingient, based on a similar logic. I also agree that longer surface stays (seven days for initial Orion missions) are perfectly justified.

In a lunar-surface rendezvous architecture (as Jon proposes,) a total crew of three astronauts will be able to achieve the type of mission I have laid out. For a lunar-orbit rendezvous profile (as NASA has baselined,) a fourth crewmember is only justified if he/she stays aboard the Orion command module. Frankly, if I were an astronaut on the moon, I'd like to know that my buddy was up there in the command module, if for no other reason than to back up the automated control systems which will handle rendezvous after we left the lunar surface.

After thinking about it, Jon's proposal sounds a lot like Early Lunar Access from General Dynamics back in 1992. ELA was a brilliant plan, but it came in the dying days of the Space Exploration Initiative. Nevertheless, ELA stood in stark contrast to the "First Lunar Outpost" plan, which returned to the Direct Landing mission mode and made use of an enhanced Saturn V known as "Comet."