Space

Glide Back

17 Comments

Jon Goff has put up the fourth installment of his survey on space transport concepts. As he noted earlier, it could be the basis of a useful textbook on the subject, with a lot more work and analysis (and accompanying graphs and figures). When I was on The Space Show the other day, David got a chat from an aerospace engineering student about when he’d learn how to design low-cost launchers, because he hadn’t seen anything about that in any of his course work. This would be the text for such a course.

As Jon notes, TPS is a common thread in making reusable entry vehicles practical and cost effective. The Shuttle tiles are too high maintenance, and risky (as we saw with Columbia). However, a lot of these issues go away if the vehicle “swallows the tank” (as Rockwell and others proposed in their X-33 concepts). No external tank dramatically reduces the risk to damaging the tiles, and containing a hydrogen (or even hydrocarbon, though to a lesser degree) fuel tank makes the vehicle much more “fluffy”* on entry, considerably reducing the heat load. Because of the ET, Shuttle had unique TPS issues that future vehicles are less likely to have to worry about. And also, as Jon notes, XCOR is in the process of building exactly the type of “X-vehicle” that will be useful to start to prove out both trajectory and TPS concepts, something that NASA should have done years ago, and probably would have had it still been NACA.

[Update late afternoon]

Notwithstanding the silly microkerfuffle in comments, I should add that when I came up with the term “fluffy,” it didn’t occur to me to apply it to a vehicle. I really intended it to apply to something that actually is fluffy (i.e., homogeneously undense, e.g., liquid hydrogen), rather than something that has low average density, but very high local density with vast volumes of low or zero density. We should probably come up with some other word to describe a large empty tank, to distinguish between the homogeneous and heterogeneous cases.

*A word I came up with years ago at Rockwell to mean the opposite of “dense.” Others may have come up with it independently.

Political Commentary, Technology and Society

Guilt-Free Petroleum

11 Comments

Some thoughts from Thomas James:

…the amusing part is that it is theoretically a carbon-negative fuel source — the microbes take more carbon out of the atmosphere than what they excrete as a useable oil (if that doesn’t seem to make sense, recall that the microbes themselves require carbon for their own structure).

On the other hand, since this approach requires genetic engineering, the watermelons and luddites will no doubt put the kibosh on it regardless of its benefits — the only thing more intolerable than the idea of environmental-guilt-free petroleum sustaining the Western lifestyle of individuality, independence, and material happiness is the knowledge that that guilt-free petroleum comes from “frankenbacteria.”

They’ll hate it even without the bioengineering. As noted, it doesn’t require us to tighten our hair shirts, or depopulate the planet.

Space, Technology and Society

Thoughts On The Number Six

11 Comments

Over at Rockets and Such.

So, it goes from Ares 5 to Ares 6, and it still doesn’t satisfy the mission requirement. And now it has outgrown the MLP.

There’s a concept in the development of a space vehicle known as “chasing your tail,” in which the need to add something to the vehicle (like adequate structural strength, with margin) results in more weight, which results in the need for bigger or more engines to push it, which results in the need for more propellant capacity to accelerate the added mass, which results in…

And the design won’t close.

Now in fact, it is probably possible to get this design to close–bigger vehicles are easier in that regard than small ones. But regardless of the size of the vehicle, mission needs are always going to grow (and they still don’t really have solid numbers on the EDS/Altair/cargo requirements). So it won’t be able to get the mission concept (one and a half launch) to close, particularly as we move beyond the moon, even if it can be done for the moon.

The rationale for the heavy lifter has always been to avoid the complication of orbital assembly (apparently, the false lesson learned from our success with assembling ISS is that we should throw away all that experience, and take an entirely different approach for VSE). But it’s already a “launch and half” mission, needing both Ares 1 and Ares 56, so they’re not even avoiding it–they’re only minimizing it. And even if the lunar mission doesn’t outgrow the Ares 6, it won’t be able to do a Mars mission in a single launch. So if we need to learn to do orbital assembly (and long-term propellant storage) anyway, why postpone it? Why not take the savings from not developing an unneeded heavy lifter (and new crew launch vehicle), and invest it in orbital infrastructure, tools and technology to provide a flexible system that can be serviced by a range of launch vehicles, without the single-point failure of Ares? These are the kinds of issues that a new administrator will have to consider next year.

And don’t get me started on the Ares 1 problems:

The currently favored mitigation approaches – still undergoing a trade study – for thrust oscillation will add around 500 lbs to Orion for shock mounting on the crew seats and vital components.

So, because the geniuses behind this concept decided to put the crew on top of the world’s biggest organ pipe, they’ll add a quarter of a ton to an already-overweight vehicle with no margin, so that the astronauts will (might?) be able to survive watching the rest of the capsule being vibrated even more intensely around them.

There is a word for this. It starts with a “k” and ends with “ludge.” And then there’s this.

Thrust oscillation is now categorized as a 5×4 risk for the upper stage.

I’m not sure which axis is which in that formulation, but it either means that there is a very high likelihood of a catastrophic outcome, or that that it is probable that there will be a near-catastrophic outcome. And no mitigation has yet been found.

They really need to consider going from one and a half launches to (at least) two launches of a single medium-sized vehicle type. Two launches is two launches, it would save them a huge amount of development costs, provide much better economies of scale in operation and production, and get completely around the “stick” idea, which is proving to be a programmatic disaster waiting to happen, if it hasn’t already. Let us finally end the cargo cult of Apollo, and develop real infrastructure.

[Late morning update]

Here’s more discussion over at NASA Space Flight.

[Update a few minutes later]

In a post from a week ago, Chair Force Engineer has some related thoughts as well, on the wisdom of choosing solids at all:

The solid-liquid trade study is one that couldn’t have been adequately analyzed during the 60 days of the ESAS study, and will likely end up as an interesting footnote in the Ares story. The question is whether the Ares story will fall into the genre of historical nonfiction, or fantasy and tragedy. If the latter is true, perhaps liquids were the answer after all. But the decision to not cap the weight of Ares V (even at the expense of payload) is one that taxpayers shouldn’t forget if the massive rocket, and its shiny new infrastructure, ever get off the drawing board.

It seems pretty clear (as it did at the time) that the decision to build “the Stick” was pre-ordained, and that the sixty-day study was a rationalization, not a rationale, and that none of the CE&R recommendations were seriously considered. An Administrator Steidle would no doubt want to revisit it.

Political Commentary, Science And Society, Technology and Society

Seek, And Ye Shall Find

32 Comments

Another huge oil discovery in Brazil.

What’s amazing is not so much that Congress won’t allow us to pump oil, which we badly need to do. They won’t even allow us to look for it, especially if it’s in a “pristine” (aka barren coastal plain, frozen in the winter and a mosquito-infested bog in the summer) region, at least according to Senator McCain.

What are they afraid we might find?

Business, Humor, Technology and Society

Only Cat 5?

12 Comments

For that kind of money, I’d expect Cat 8, at least.

An audiophile and his money are soon parted.

[Update a few minutes later]

As noted, the Amazon customer reviews are hilarious.

[Update in the evening]

Stephen Dawson (from Down Under) has a defense (albeit pretty flimsy. as he admits) of Denon.

I have to admit my disappointment as well. I’d always respected Denon up until this. As someone in comments said, one hopes that the marketing person responsible will have a few of these cables run through them from one end to the other. Or be keelhauled with them.

Space, Space History

Len Cormier’s Final Flight Plan

I just got the sad news from Pat Kelley:

Len took his final journey this morning, passing peacefully. His family is going to have his ashes interred at Arlington cemetery, but I have no schedule. For those who wish to express condolences, you can reach his life partner, Anne Greenglass via email, [email me for the address if you want to do so–rs].

I tried to address this notice to all the people on my list, but I’m sure there are others I may have missed, so please forward this to anyone else you feel would want to know. I do intend to continue trying to get backing for Len’s last design (Space Van 2010) as a tribute.

Len was a truly unique man, and a rare breed these days. Always the gentleman, honest to a fault, and always ready to give credit where it was due (and sometimes even allowing the unworthy to take credit for his work, for the sake of an important effort). He is unreplaceable, and will be sorely missed.

Ad astra, cum laetitia, Len.

[Previous post here]

Space, Space History

Len Cormier’s Final Flight Plan

3 Comments

I just got the sad news from Pat Kelley:

Len took his final journey this morning, passing peacefully. His family is going to have his ashes interred at Arlington cemetery, but I have no schedule. For those who wish to express condolences, you can reach his life partner, Anne Greenglass via email, [email me for the address if you want to do so–rs].

I tried to address this notice to all the people on my list, but I’m sure there are others I may have missed, so please forward this to anyone else you feel would want to know. I do intend to continue trying to get backing for Len’s last design (Space Van 2010) as a tribute.

Len was a truly unique man, and a rare breed these days. Always the gentleman, honest to a fault, and always ready to give credit where it was due (and sometimes even allowing the unworthy to take credit for his work, for the sake of an important effort). He is unreplaceable, and will be sorely missed.

Ad astra, cum laetitia, Len.

[Previous post here]

Media Criticism, Political Commentary, War Commentary

The George Romney Democrats

9 Comments

James Kirchick writes that the Democrats are trying to lie their party to victory, and the country to defeat in Iraq:

In 2004, the Senate Intelligence Committee unanimously approved a report acknowledging that it “did not find any evidence that administration officials attempted to coerce, influence or pressure analysts to change their judgments.” The following year, the bipartisan Robb-Silberman report similarly found “no indication that the intelligence community distorted the evidence regarding Iraq’s weapons of mass destruction.”

Contrast those conclusions with the Senate Intelligence Committee report issued June 5, the production of which excluded Republican staffers and which only two GOP senators endorsed. In a news release announcing the report, committee Chairman John D. Rockefeller IV got in this familiar shot: “Sadly, the Bush administration led the nation into war under false pretenses.”

Yet Rockefeller’s highly partisan report does not substantiate its most explosive claims. Rockefeller, for instance, charges that “top administration officials made repeated statements that falsely linked Iraq and Al Qaeda as a single threat and insinuated that Iraq played a role in 9/11.” Yet what did his report actually find? That Iraq-Al Qaeda links were “substantiated by intelligence information.” The same goes for claims about Hussein’s possession of biological and chemical weapons, as well as his alleged operation of a nuclear weapons program.

Four years on from the first Senate Intelligence Committee report, war critics, old and newfangled, still don’t get that a lie is an act of deliberate, not unwitting, deception. If Democrats wish to contend they were “misled” into war, they should vent their spleen at the CIA.

Yes. Bill Clinton’s CIA, since George Bush foolishly left George Tenant in charge of it, even after 911, and never even seriously attempted to clean house, other than the failed attempt by Porter Goss. The president got bad intelligence. But the Democrats are being mendacious in their selective memory and rewriting of history.

I loved this:

A journalist who accompanied Romney on his 1965 foray to Vietnam remarked that if the governor had indeed been brainwashed, it was not because of American propaganda but because he had “brought so light a load to the laundromat.” Given the similarity between Romney’s explanation and the protestations of Democrats 40 years later, one wonders why the news media aren’t saying the same thing today.

I assume that the last phrase is simply a rhetorical flourish. There’s no reason to wonder at all.

Political Commentary, Space, Space and Campaign 2008

The Way Forward

8 Comments

Very little in this essay is new to people who have been following the arguments in space policy circles for years, but it’s useful to pull it all together into one place, and bring it up to date. I and many others have long advocated that we need to resurrect NACA (which was absorbed into NASA half a century ago) and start developing technology that can support private industry, as we did for aviation. With the new private space passenger vehicles now starting to be developed, the time is ripe for it, and Jeff Foust and Charles Miller have made a very powerful case. This should be must reading for both presidential campaigns.

[Update mid morning]

This piece I wrote a few years ago on the centennial of flight seems pertinent.

[Mid-afternoon update]

More commentary over at Jeff’s site, Space Politics.

Biting Commentary about Infinity…and Beyond!