Space

Now We’re Just Haggling Over The Price

Jon Goff has some more good posts up on exploration (and particularly lunar) architectures. Here’s a key point that undercuts NASA’s rationale for HLVs:

Why doesn’t NASA land enough stuff to support 4 people for 6 months on a single lander? Or 6 people for a year? Because it would require much too big of a lander, which would cost too much to develop, and way too much to operate. By making the lander smaller, and less capable, but using LSR, ESAS provides a much cheaper approach than trying to do a Battlestar Galactica scale lunar lander. However, you could see where that logic goes…

And Doug Stanley more or less admitted it. He said that had the 4 people for 7 days edict not been “blessed” by Mike Griffin as one of the ground rules, that EELV based architectures would have traded a lot better compared to the chosen ESAS architecture. And he’s right. All the numbers I’ve run show that you could probably do a reasonable 2-man lunar architecture using st0ck, or nearly st0ck EELVs (or EELV equivalents like Falcon IX if it becomes available).

They admit the need for assembly on the moon, because they know that (as Jon notes) it’s completely unrealistic to get a full-up base to the surface with a single launch of any vehicle short of Sea Dragon (come to think of it, that’s one HLV that I could get behind, because it’s innovative and wouldn’t necessarily cost that much). Now admittedly, it is easier to do assembly in a gravity field (though in some ways, it’s harder as well, since with weight, you need cranes, etc.). But it’s not so much easier that they should have ruled out doing orbital assembly, something that we need to learn to do anyway, and that they will have to do for Mars, even with Ares V.

Again, as Jon points out, the entire architecture, and justification for an expensive (in both development and operations) heavy lifter is based on an arbitrary requirement–four crew for seven days. Remove that constraint, and the trade space blossoms tremendously. But it apparently doesn’t satisfy political imperatives, whatever their source.

Space

Now We’re Just Haggling Over The Price

Jon Goff has some more good posts up on exploration (and particularly lunar) architectures. Here’s a key point that undercuts NASA’s rationale for HLVs:

Why doesn’t NASA land enough stuff to support 4 people for 6 months on a single lander? Or 6 people for a year? Because it would require much too big of a lander, which would cost too much to develop, and way too much to operate. By making the lander smaller, and less capable, but using LSR, ESAS provides a much cheaper approach than trying to do a Battlestar Galactica scale lunar lander. However, you could see where that logic goes…

And Doug Stanley more or less admitted it. He said that had the 4 people for 7 days edict not been “blessed” by Mike Griffin as one of the ground rules, that EELV based architectures would have traded a lot better compared to the chosen ESAS architecture. And he’s right. All the numbers I’ve run show that you could probably do a reasonable 2-man lunar architecture using st0ck, or nearly st0ck EELVs (or EELV equivalents like Falcon IX if it becomes available).

They admit the need for assembly on the moon, because they know that (as Jon notes) it’s completely unrealistic to get a full-up base to the surface with a single launch of any vehicle short of Sea Dragon (come to think of it, that’s one HLV that I could get behind, because it’s innovative and wouldn’t necessarily cost that much). Now admittedly, it is easier to do assembly in a gravity field (though in some ways, it’s harder as well, since with weight, you need cranes, etc.). But it’s not so much easier that they should have ruled out doing orbital assembly, something that we need to learn to do anyway, and that they will have to do for Mars, even with Ares V.

Again, as Jon points out, the entire architecture, and justification for an expensive (in both development and operations) heavy lifter is based on an arbitrary requirement–four crew for seven days. Remove that constraint, and the trade space blossoms tremendously. But it apparently doesn’t satisfy political imperatives, whatever their source.

Space

Silk Purses From Sow’s Ears

When NASA first proposed a single-SRB-based launcher, one of the issues that jumped out immediately to many familiar with vehicle design and Shuttle design was roll control. As designed for the Shuttle, there are two SRBs, both of which can gimbal the engines. This allows roll control of the Shuttle stack by gimbaling them in opposite directions. But when there’s only one, the engine gimbal provides pitch and yaw control, but there’s no way for it to control roll.

There are two potential solutions to this–to modify the SRB itself to add roll-control thrusters, or to incorporate them into the new upper stage. The latter has the disadvantage of oversizing the roll-control system for the period after stage separation, which adds weight and affects performance, but it simplifies design by requiring only one system.

In any event, the concept seems to be in trouble. Now this certainly isn’t a show stopper, and issues like this are inevitable in the development of a new launch vehicle, but it’s just one more demonstration of the fact that deriving a new launcher from existing pieces isn’t as easy as has been advertised by many, both within and out of the agency.

[Late morning update]

Gary Hudson emails one other option:

There is a third possibility: let it roll. Depending on the rate and duration, it may not be a problem. Some current vehicles do this (Taurus, for one) and we are planning a subset of it for the AirLaunch QuickReach. In our case, we have a Stage Two roll thruster but its purpose is to limit the rate, not hold a specific roll attitude. Makes for a much small thruster. It is later used as part of the normally smaller sized Stage Two attitude control subsystem.

Space

Silk Purses From Sow’s Ears

When NASA first proposed a single-SRB-based launcher, one of the issues that jumped out immediately to many familiar with vehicle design and Shuttle design was roll control. As designed for the Shuttle, there are two SRBs, both of which can gimbal the engines. This allows roll control of the Shuttle stack by gimbaling them in opposite directions. But when there’s only one, the engine gimbal provides pitch and yaw control, but there’s no way for it to control roll.

There are two potential solutions to this–to modify the SRB itself to add roll-control thrusters, or to incorporate them into the new upper stage. The latter has the disadvantage of oversizing the roll-control system for the period after stage separation, which adds weight and affects performance, but it simplifies design by requiring only one system.

In any event, the concept seems to be in trouble. Now this certainly isn’t a show stopper, and issues like this are inevitable in the development of a new launch vehicle, but it’s just one more demonstration of the fact that deriving a new launcher from existing pieces isn’t as easy as has been advertised by many, both within and out of the agency.

[Late morning update]

Gary Hudson emails one other option:

There is a third possibility: let it roll. Depending on the rate and duration, it may not be a problem. Some current vehicles do this (Taurus, for one) and we are planning a subset of it for the AirLaunch QuickReach. In our case, we have a Stage Two roll thruster but its purpose is to limit the rate, not hold a specific roll attitude. Makes for a much small thruster. It is later used as part of the normally smaller sized Stage Two attitude control subsystem.

Space

Silk Purses From Sow’s Ears

When NASA first proposed a single-SRB-based launcher, one of the issues that jumped out immediately to many familiar with vehicle design and Shuttle design was roll control. As designed for the Shuttle, there are two SRBs, both of which can gimbal the engines. This allows roll control of the Shuttle stack by gimbaling them in opposite directions. But when there’s only one, the engine gimbal provides pitch and yaw control, but there’s no way for it to control roll.

There are two potential solutions to this–to modify the SRB itself to add roll-control thrusters, or to incorporate them into the new upper stage. The latter has the disadvantage of oversizing the roll-control system for the period after stage separation, which adds weight and affects performance, but it simplifies design by requiring only one system.

In any event, the concept seems to be in trouble. Now this certainly isn’t a show stopper, and issues like this are inevitable in the development of a new launch vehicle, but it’s just one more demonstration of the fact that deriving a new launcher from existing pieces isn’t as easy as has been advertised by many, both within and out of the agency.

[Late morning update]

Gary Hudson emails one other option:

There is a third possibility: let it roll. Depending on the rate and duration, it may not be a problem. Some current vehicles do this (Taurus, for one) and we are planning a subset of it for the AirLaunch QuickReach. In our case, we have a Stage Two roll thruster but its purpose is to limit the rate, not hold a specific roll attitude. Makes for a much small thruster. It is later used as part of the normally smaller sized Stage Two attitude control subsystem.

War Commentary

Barbarians At The Gate

Victor Davis Hanson writes that the West faces a crisis of confidence:

Just imagine in our present year, 2006: plan an opera in today’s Germany, and then shut it down. Again, this surrender was not done last month by the Nazis, the Communists, or kings, but by the producers themselves in simple fear of Islamic fanatics who objected to purported bad taste. Or write a novel deemed unflattering to the Prophet Mohammed. That is what did Salman Rushdie did, and for his daring, he faced years of solitude, ostracism, and death threats–and in the heart of Europe no less. Or compose a documentary film, as did the often obnoxious Theo Van Gogh, and you may well have your throat cut in “liberal” Holland. Or better yet, sketch a simple cartoon in postmodern Denmark of legendary easy tolerance, and then go into hiding to save yourself from the gruesome fate of a Van Gogh. Or quote an ancient treatise, as did Pope Benedict, and then learn that all of Christendom may come under assault, and even the magnificent stones of the Vatican may offer no refuge–although their costumed Swiss Guard would prove a better bulwark than the European police. Or write a book critical of Islam, and then go into hiding in fear of your life, as did French philosophy teacher Robert Redeker.

…Note also the constant subtext in this new self-censorship of our supposedly liberal age: the fear of radical Islam and its gruesome methods of beheadings, suicide bombings, improvised explosive de-vices, barbaric fatwas, riotous youth, petrodollar-acquired nuclear weapons, oil boycotts and price hikes, and fist-shaking mobs, as the seventh century is compressed into the twenty-first.

In contrast, almost daily in Europe, “brave” artists caricature Christians and Americans with impunity. And we know what explains the radical difference in attitudes to such freewheeling and “candid” expression–indeed, that hypocrisy of false bravado, of silence before fascists and slander before liberals is both the truth we are silent about, and the lie we promulgate.

There is, in fact, a long list of reasons, among them most surely the assurance that cruel critics of things Western rant without being killed. Such cowards puff out their chests when trashing an ill Oriana Fallaci or a comatose Ariel Sharon or beleaguered George W. Bush in the most demonic of tones, but they prove sunken and sullen when threatened by a thuggish Dr. Zawahiri or a grand mufti of some obscure mosque.

[Evening update]

Eric Raymond had a post last February that’s quite relevant.

Science And Society

Only Three Times As Much?

I know you’ll be shocked to learn this, but women talk more than men. I also found this an interesting statistic:

…what the male brain may lack in converstation and emotion, they more than make up with in their ability to think about sex.

Dr Brizendine says the brain’s “sex processor” – the areas responsible for sexual thoughts – is twice as big as in men than in women, perhaps explaining why men are stereotyped as having sex on the mind.

Or, to put it another way, men have an international airport for dealing with thoughts about sex, “where women have an airfield nearby that lands small and private planes”.

Studies have shown that while a man will think about sex every 52 seconds, the subject tends to cross women’s minds just once a day, the University of California psychiatrist says.

My, how politically incorrect.

Popular Culture

Close, But No Cigar

What American accent do you have?

Your Result: The Inland North

You may think you speak “Standard English straight out of the dictionary” but when you step away from the Great Lakes you get asked annoying questions like “Are you from Wisconsin?” or “Are you from Chicago?” Chances are you call carbonated drinks “pop.”
The Midland
The Northeast
Philadelphia
The South
The West
Boston
North Central
What American accent do you have?
Take More Quizzes

OK, they’ve got the general region down, but they don’t seem to be able to differentiate between Michigan and Wisconsin, which is pretty weird. Just one more question (bubblers versus drinking fountains) would nail it down.

And for the record, I’m a “pop person.” Soda is a thing with ice cream.

Biting Commentary about Infinity…and Beyond!