The Blinne Blog

Shuttle Undone By Environmental Regulation

It has been alleged that environmental regulations have undone the Space Shuttle. That's because a freon-based foam adheres better to the tank than a non-freon-based one.

Environmental requirements requiring removal of freon from the process for spraying the foam insulation onto the tank. NASA has said that the freon-free application method resulted in foam that initially did not adhere to the tank as well, but changes were later made to strengthen the bond of the environmentally friendly foam.

Let's see if this is true. First, a diagram from the Columbia investigation of the various insulation types.

Now a diagram from NASA showing where the failure occurred on Discovery. More detailed pictures to be found at California Yankee.

The foam that failed is NCFI 24-124. Again from the Columbia report.

Most of the External Tank is insulated with three types of spray-on foam. NCFI 24-124, a polyisocyanurate foam applied with blowing agent HCFC 141b hydrochlorofluorocarbon, is used on most areas of the liquid oxygen and liquid hydrogen tanks. NCFI 24-57, another polyisocyanurate foam applied with blowing agent HCFC 141b hydrochlorofluorocarbon, is used on the lower liquid hydrogen tank dome. BX-250, a polyurethane foam applied with CFC-11 chlorofluorocarbon, was used on domes, ramps, and areas where the foam is applied by hand. The foam types changed on External Tanks built after External Tank 93, which was used on STS-107, but these changes are beyond the scope of this section.

So, what's BX-250 and HCFC 141b? Let's ask NASA.

Environmental Protection Agency

In 1987, the United States and 45 other nations adopted the "Montreal Protocol on Substances that Deplete the Ozone Layer." Under the Protocol, class I ozone depleting compounds, such as chlorofluorocarbon 11 known as CFC 11 -- the Freon-based blowing agent used in the production of the External Tank's foam -- was to be phased out of production by the end of 1995. Production of these compounds after 1995 is allowed only by "Essential Use Exemption" and must have Montreal Protocol approval.

After extensive testing the External Tank project proposed hydro chlorofluorocarbon HCFC 141b as the CFC 11 replacement. HCFC 141b is a blowing agent more environmental regulation compliant. At the same time, the Environmental Protection Agency allowed the External Tank program to continue use of stockpiled supplies of CFC 11until HCFC 141b was certified for use on the Space Shuttle and phased in.

However, in 1999, the EPA proposed to expand its regulations by implementing a ban on nonessential products that release class I ozone-depleting substances under section 610 of the Clean Air Act. Under the proposed rule, sale and distribution of BX 250, used to insulate part of the External Tank, would have been banned because it contains CFC 11. NASA asked the EPA to revise the proposed rule to provide an exemption for BX 250 and other foam containing CFC 11 used in applications associated with space vehicles.

The EPA allowed the exemption but limited it to the Thermal Protection System of the Shuttle's External Tank and only allowed the use of CFC 11 as a blowing agent when no other chlorofluorocarbons are used in the foam product.

The "new" foam containing HCFC 141b was first used on the liquid hydrogen tank aft dome of ET-82 and flew on STS-79 in 1996. The foam was implemented on the tank's acreage, or its larger portions, beginning with ET-88, which flew on STS-86 in 1997. In December 2001, BX-265, which contains HCFC 141b, first flew as a replacement of BX-250. However BX250 continued to be flown as BX-265 was implemented step wise through the manufacturing process.

So, the freon-based BX-250 has replaced by the non-freon-based HCFC 141b. Is NASA passing the buck or did the EPA actually do what they said? NASA's summary is accurate, here's the EPA report.

EPA received a comment from the National Aeronautics and Space Administration (NASA) regarding the use of specific plastic foam products for the space shuttle. NASA identified one particular product, BX-250, a foam which is part of the thermal protection system of the Space Shuttle External Tank and which uses CFC-11 as a blowing agent. NASA stated that ``although extensive efforts have been made and continue to be made to replace this material, no viable alternative has been identified.'' NASA requested that EPA revise the proposed rule to provide an exemption for CFC-blown foam products in applications that are associated with space vehicles. NASA suggested that EPA consider using the same language that EPA has previously adopted under 40 CFR part 63, subpart GG (40 CFR 63.742) for the National Emissions Standards for Hazardous Air Pollutants (NESHAPs) program. NASA provided EPA with additional information concerning its proactive pursuit of potential alternative blowing agents.

Since human space flight safety is of paramount importance to NASA, prior to implementing any new material, that material must undergo a rigorous development and qualification program for which no suitable substitute has yet been identified. NASA requested that EPA consider using the language at 40 CFR 63.742:

Space vehicle means a man-made device, either manned or unmanned, designed for operation beyond earth's atmosphere. This definition includes integral equipment such as models, mock-ups, prototypes, molds, jigs, tooling, hardware jackets, and test coupons. Also included is auxiliary equipment associated with test, transport, and storage, which through contamination can compromise the space vehicle performance.

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EPA agrees that an exception is necessary, but EPA disagrees with NASA's proposed language. This language is far broader than what EPA concludes is actually necessary based on an evaluation of the information NASA presented. If EPA were to simply exempt all foams used for any applications associated with space vehicles EPA could be exempting products where there are already suitable substitutes. NASA only provided information concerning one particular type of foam used in applications associated with the Space Shuttle External Tank.

Therefore, based on that information, through this action, EPA will modify Sec. 82.66(c) to provide an exemption for foam products manufactured with or containing Class I substances that are used as part of the thermal protection system of external tanks for space vehicles and will add the definition of space vehicles found at Sec. 63.742 to Sec. 82.62. The exemption will be limited to the use of CFC-11 as a blowing agent and where no other CFCs are contained in the foam product. Although EPA did not propose this exemption or the additional definition, they are logical outgrowths of the comment submitted by NASA and thus it is appropriate to proceed to final action without providing any additional proposal or opportunity for further comment.

Thanks EPA for killing our astronauts.

We're All Moderates and Catholics

The word catholic means universal. So, in that sense all Christians are little-c catholics. In the midst of an otherwise decent editorial I found an interesting error in David Brooks concerning the Roberts' nomination. First, the quote. A Competent Conservative - New York Times.

Confirmation battles have come to seem of late like occasions for bitterly divided Catholics to turn political battles into holy war Armageddons. Most of the main Democrats on the Judiciary Committee are Catholics who are liberal or moderate (Kennedy, Biden, Durbin, Leahy), and many of the most controversial judges or nominees are Catholics who are conservative (Scalia, Thomas, Pryor). When they face off, you get this brutal and elemental conflict over the role morality should play in public life.

My question who is the moderate amongst the senators mentioned? And when did Justice Thomas, an Episcopalian, become Catholic? Thomas may very well be Anglo-Catholic and attended a Catholic elementary school but that is not the same thing.  It seems that being a moderate Catholic is where it's at these days. I guess anybody can be one, too. Hat tip: Polipundit.

Rush Flunks Science Again

Every time Rush Limbaugh speaks about science I get nervous. Rush did it again today. He was talking about the chemical contamination caused by arctic seabirds. Rush didn't read the story linked above very carefully because he was thinking that the contamination was natural and the bird droppings did not contain any man-made compounds. The abstract of the study in Science betrays this point:

Long-range atmospheric transport of pollutants is generally assumed to be the main vector for arctic contamination, because local pollution sources are rare. We show that arctic seabirds, which occupy high trophic levels in marine food webs, are the dominant vectors for the transport of marine-derived contaminants to coastal ponds. The sediments of ponds most affected by seabirds had 60 times higher DDT, 25 times higher mercury, and 10 times higher hexachlorobenzene concentrations than nearby control sites. Bird guano greatly stimulates biological productivity in these extreme environments but also serves as a major source of industrial and agricultural pollutants in these remote ecosystems. [emphasis mine]

DDT, Hg, and HCB are not naturally occurring compounds. The study makes the exact opposite point that Limbaugh does. In addition to atmospheric drift, seabirds are vectors that contaminate the Arctic even though it is far away from the original source of the contamination.

Who Was Novak's Original Source?

Last year, I caught second-hand speculation within the CIA that Valerie Plame was "outed" from inside the CIA because she and her husband were politicizing intelligence. (A friend of mine had contacts in the Iraq Survey Group.) That speculation seems to be even more likely today.

Question from the Captain's Quarters.

I think it may even be more than that, at least on the media's part, and specific to the New York Times. They know who Judith Miller's source is, and they're trying their best to keep it quiet. One wonders why they're carrying so much water for a story they never broke. Could it have something to do with their publication of Joseph Wilson's original op-ed article that started the whole mess?

I could care less who Miller's source was (unless it was the same as Novak's). Rather, who was Novak's original source given that Rove was the confirming one? Let's look at the characteristics as described by Novak:

1. A senior administration figure
2. Not a partisan gunslinger
3. Would know the answer of why the CIA sent Wilson to Niger

This would give us either Colin Powell or George Tenet. (Commenters please give any other candidates here.) A spokesman for Powell denied that he ever talked with Novak at all about the Plame affair. This leaves George Tenet. A friend of Wilson's asked Novak about Wilson on July 8, 2003, the same day that Rove confirmed Novak's story. Novak told Wilson's friend:

“Wilson’s an asshole. The CIA sent him. His wife, Valerie, works for the CIA. She’s a weapons of mass destruction specialist. She sent him.”

On July 10, Wilson confronted Novak before Novak ran the story:

Novak apologized, and then asked if I would confirm what he had heard from a CIA source: that my wife worked at the Agency. [emphasis mine]

After Novak ran his story, Wilson contacted Novak again and noted the discrepancy of Novak's sourcing. Novak replied, "I misspoke the first time I contacted you".

What if Novak didn't misspoke and was trying to protect his source? What if characteristic number 4 is works for the CIA? That leaves George Tenet as the source of who sent Wilson to Niger. Whether the source specifically named Valerie Plame is difficult to surmise because apparently her identity was an open secret. In the end, that's for the prosecutor and the grand jury to figure out. 

Bill Clinton: Statesman

Yesterday, Tony Snow gave a challenge on his radio show. He asked for a single quote where a Democrat was acting like a statesman in light of the London bombings. This was a difficult test. However, I found a notable exception from a surprising quarter.

The Rocky Mountain News reported the following quote from former President Bill Clinton:

Clinton, a late addition to the festival's lineup, fielded questions from Aspen Institute President Walter Isaacson and select participants in the event that wasn't open to the public.

Clinton pointed out that in the recent national elections in Iraq, turnout was an astounding 58 percent - higher than in recent U.S. elections. "It's clearly a legitimate process and the people want it to work, so I think we can try to make it work," Clinton said.

The former president said the United States and its allies should continue to help Iraq build its defense capabilities. Clinton also scoffed at the notion that America is embroiled in another war like Vietnam.

"This is not Vietnam. It might be a quagmire, but it won't be for the reason it was in Vietnam. Our problem (in Vietnam) was we didn't have a legitimate government to back," Clinton said.

Clinton also commented on Thursday's bombings in London, saying that, from the terrorists' viewpoint, it was a huge mistake. "I actually think they made a tactically bad decision to do this thing in London, from their point of view," Clinton said. "The British underwent the (Irish Republican Army) terrorism and the blitz bombing (from the Germans in World War II), and they are tough as nails. And they can take it and dish it out."

Well done, Mr. President, and thank you.

Evolutionary Straw Men

The New York Times reported today that a leading theologian of the Roman Catholic Church is concerned that the view of the Church with respect to evolution is being misrepresented.

The cardinal, Christoph Schoenborn, archbishop of Vienna, a theologian who is close to Pope Benedict XVI, staked out his position in an Op-Ed article in The New York Times on Thursday, writing, "Evolution in the sense of common ancestry might be true, but evolution in the neo-Darwinian sense - an unguided, unplanned process of random variation and natural selection - is not."

He said that he had been "angry" for years about writers and theologians, many Catholics, who he said had "misrepresented" the church's position as endorsing the idea of evolution as a random process. [emphasis mine]

Evangelical and Catholic scientists expressed dismay with the Cardinal's statements.

Dr. Francis Collins, who headed the official American effort to decipher the human genome, and who describes himself as a Christian, though not a Catholic, said Cardinal Schönborn's essay looked like "a step in the wrong direction" and said he feared that it "may represent some backpedaling from what scientifically is a very compelling conclusion, especially now that we have the ability to study DNA."

"There is a deep and growing chasm between the scientific and the spiritual world views," he went on. "To the extent that the cardinal's essay makes believing scientists less and less comfortable inhabiting the middle ground, it is unfortunate. It makes me uneasy."

"Unguided," "unplanned," "random" and "natural" are all adjectives that biologists might apply to the process of evolution, said Dr. Kenneth R. Miller, a professor of biology at Brown and a Catholic. But even so, he said, evolution "can fall within God's providential plan." He added: "Science cannot rule it out. Science cannot speak on this."

So have evolutionists misrepresented the Catholic Church's doctrine or is it the other way around? The following is a description of it at the National Center for Science Education web site:

Evolutionary Creationism (EC). Despite its name, evolutionary creationism is actually a type of evolution. Here, God the Creator uses evolution to bring about the universe according to his plan. From a scientific point of view, evolutionary creationism is hardly distinguishable from Theistic evolution, which follows it on the continuum. The differences between EC and Theistic evolution lie not in science, but in theology, with EC being held by more conservative (evangelical) Christians (D. Lamoreaux, p.c). I will therefore move on to theistic evolution.

Theistic Evolution (TE). Theistic Evolution is a theological view in which God creates through the laws of nature. Not just the physical laws, either: it is acceptable to TEs that one species can give rise to another; they accept descent with modification. TEs vary in whether and how much God is allowed to intervene — some slide pretty close to Deists. Other TEs see God as intervening at critical intervals during the history of life (especially in the origin of humans), and they in turn slide closer to PCs. In one form or another, TE is the view of creation taught at the majority of mainline Protestant seminaries, and it is the official position of the Catholic church. In 1996, Pope John Paul II reiterated the Catholic TE position, in which God created, evolution happened, humans may indeed be descended from more primitive forms, but the Hand of God was required for the production of the human soul. (John Paul II, 1996).

I included the description of evolutionary creationism (my position) because I find that the description was a fair description of what I believe. The description of the Catholic view in no way described it as endorsing "an unguided, unplanned process of random variation and natural selection". I share Drs. Collins' and Miller's concerns in that the statement could drive Evangelical and Catholic scientists away from their respective faiths by removing the middle ground.

A Way Out

With the retirement of Justice Sandra Day O'Connor we will probably embark on another divisive episode on top of the divisive episodes we have seen in the early 21st Century. Justice Connor's career was marked as being in the middle and she also was associated with compromise in church/state relationships. But how well has this compromise served us as Evangelicals living in the United States? Noah Feldman wrote a provocative piece in last Sunday's New York Times Magazine. Here he turned the compromise on its head.

In the courts, the arrangement that I'm proposing would entail abandoning the Lemon requirement that state action must have a secular purpose and secular effects, as well as O'Connor's idea that the state must not ''endorse'' religion. For these two tests, the courts should substitute the two guiding rules that historically lay at the core of our church-state experiment before legal secularism or values evangelicalism came on the scene: the state may neither coerce anyone in matters of religion nor expend its resources so as to support religious institutions and practices, whether generic or particular. These constitutional principles, reduced to their core, can be captured in a simple slogan: no coercion and no money. If no one is being coerced by the government, and if the government is not spending its money to build religious-themed monuments or support religious institutions and practices, the courts should hold that the Constitution is not violated.

Admittedly, this approach goes against the trends of the last several decades, which are for stricter regulation of public religious symbolism and more permissive authorization of government financing and support for religion. At first blush, then, the proposal may strike both sides of the current debate as mistaken, since it requires each to give up some victories in exchange for an alternative solution. Nonetheless this approach is not only faithful to our constitutional traditions; it also stands a chance of winning over secularists and evangelicals alike and beginning to close the rift between them.

As Evangelicals such a proposal is worthy of our consideration. This is because the current compromise is corrupting us. For example, those who propose Intelligent Design pretend that such a position is motivated by secular rather than religious reason. Truth is, neither those who support nor those who oppose Intelligent Design believe this. I believe in design for religious rather than scientific reasons, but I oppose so-called "Intelligent Design" because it is not honest about its motivations. By insisting on a secular purpose our religious expression is muted. The corrupting influence is that we are tempted to equivocate in order to be able to speak in the public square. Ironically, succumbing to that temptation lessens our power because in the end our witness is dependent on our truthfulness.

The other temptation is related to money. The government has their own "golden rule": He who has the gold makes the rules. When we accept government money for faith-based institutions we must accept the restrictions. This also corrupts us. One of these restrictions disallows proselytizing. While we ought not force someone to be converted, an Evangelical who cannot speak the "evangel", the good news, is a contradiction in terms. This temptation gets resolved either by not preaching the Good News or not helping the poor. The Bible makes neither of these optional.

In short, Feldman provides a way out and is a reasonable proposal as seen at least by this Evangelical. I don't have a sense how this will play with the secularists but if it is acceptable to them then maybe we can move beyond the "Culture Wars".

Deep Impact: Gone in a Flash

This image shows the initial ejecta that resulted when NASA's Deep Impact probe collided with comet Tempel 1 at 10:52 p.m. Pacific time, July 3 (1:52 a.m. Eastern time, July 4). It was taken by the spacecraft's high-resolution camera 13 seconds after impact. The image has been digitally processed to better show the comet's nucleus.

Image Credit:

NASA/JPL-Caltech/UMD

Here's the before picture of Comet Tempel 1 six minutes before it ran over NASA's Deep Impact probe at 10:52 a.m. Pacific time, July 3 (1:52 a.m. Eastern time, July 4). The picture was taken by the probe's impactor targeting sensor.

Image Credit: NASA/JPL-Caltech/UMD

Here's the before picture of the impactor spacecraft while it was being built at Ball Aerospace & Technologies Corporation, Boulder, Colo:

Image Credit: NASA/JPL/Ball Aerospace & Technologies Corporation

Images from other observatories follow beneath the fold.

The Faulkes Telescope North can clearly see the expanding ejecta in the coma. Attached is an image obtained by dividing an R-band image obtained at 08:35 UT by one at 06:24 UT. Positive (bright) pixels show the enhancement in R-band brightness in the inner coma at 08:35 UT. Image size is 85x62 arcsec, the apparent enhancement has a maximum brightness 2.5 arcsec from the center of the comet.

Image Credit: A. Fitzimmons and the Maui Deep Impact Workshop students and educators.

This is a series of images taken at the CFHT (Canada France Hawaii Telescope) equiped with the Megacam camera, pre- and post-impact. The images are 10s exposure time and were taken through the r filter. North is up, East is left. The field of view is about 120 x 120 arcsec, which corresponds to about 15,000 km at the comet. The three images of the animations were taken respectively at 05:50:47 UT, 05:52:59 UT, 05:54:03 UT (one pre-impact and two post impact). The increase of brightness after impact (which occurred at 05:52:24 UT as seen from Earth) is obvious on the second and third images.

Image Credit: R. Cabanac (CFHT), J. Pittichova, Y. Fernandez, K. Meech (Institute for Astronomy, Hawaii), M.B. Laychak and P. Martin (CFHT)

What Are the Limits of Conventional Computing?

For their 125th anniversary Science magazine asked the Top 25 science questions, one of which is in my area of expertise. That question is:  What Are the Limits of Conventional Computing?.

At first glance, the ultimate limit of computation seems to be an engineering issue. How much energy can you put in a chip without melting it? How fast can you flip a bit in your silicon memory? How big can you make your computer and still fit it in a room? These questions don't seem terribly profound.

Unless of course, you've actually been involved like I have in semiconductor design. It always amazes us that any of this stuff works. With time, the physics gets nastier and nastier. When I started my career we were designing 4 micron gates (the distance measured here are the length of the gate of the transistor). Now we are working on 90 nm gates and next year it will be 65 nm. We now have to worry about capacitance, resistance, inductance, setup times, hold times, on chip variation, power consumption, crosstalk avoidance, electromigration, latch up, charge antennas, planarization, leakage, and electrostatic discharge (and these are just the ones I can think of off the top of my head).

In fact, computation is more abstract and fundamental than figuring out the best way to build a computer. This realization came in the mid-1930s, when Princeton mathematicians Alonzo Church and Alan Turing showed--roughly speaking--that any calculation involving bits and bytes can be done on an idealized computer known as a Turing machine. By showing that all classical computers are essentially alike, this discovery enabled scientists and mathematicians to ask fundamental questions about computation without getting bogged down in the minutiae of computer architecture.

This is true. In fact, the basic architecture of a computer has not fundamentally changed since Turing described binary digits, von Neumann developed automata theory, and Shannon developed information theory before and during World War II.

For example, theorists can now classify computational problems into broad categories. P problems are those, broadly speaking, that can be solved quickly, such as alphabetizing a list of names. NP problems are much tougher to solve but relatively easy to check once you've reached an answer. An example is the traveling salesman problem, finding the shortest possible route through a series of locations. All known algorithms for getting an answer take lots of computing power, and even relatively small versions might be out of reach of any classical computer.

Mathematicians have shown that if you could come up with a quick and easy shortcut to solving any one of the hardest type of NP problems, you'd be able to crack them all. In effect, the NP problems would turn into P problems. But it's uncertain whether such a shortcut exists--whether P = NP. Scientists think not, but proving this is one of the great unanswered questions in mathematics.

First some definitions. P stands for polynomial time and NP stands for non-deterministic polynomial time. It is really, really important to find an order P solution. Given a fast enough traditional computer, this can be solved in reasonable time. An NP complete problem is in essence unsolvable for a computer. To see how many problems are probably NP complete check out this non-exhaustive list. If a mathematician can show P equals NP or P does not equal NP, it will be an instant Fields Medal for such an individual.

If it is the latter we may need to abandon the von Neumann architecture that has served us so well. But, how would we do that?

But there is a realm beyond the classical computer: the quantum. The probabilistic nature of quantum theory allows atoms and other quantum objects to store information that's not restricted to only the binary 0 or 1 of information theory, but can also be 0 and 1 at the same time. Physicists around the world are building rudimentary quantum computers that exploit this and other quantum effects to do things that are provably impossible for ordinary computers, such as finding a target record in a database with too few queries. But scientists are still trying to figure out what quantum-mechanical properties make quantum computers so powerful and to engineer quantum computers big enough to do something useful.

By learning the strange logic of the quantum world and using it to do computing, scientists are delving deep into the laws of the subatomic world. Perhaps something as seemingly mundane as the quest for computing power might lead to a newfound understanding of the quantum realm.

The reason why quantum computing could be so powerful is the difference between a bit and a qubit. A qubit consists of multiple entangled quantum states. A bit can be 0 or 1. A qubit consists of superpositions of whole binary strings.  Thus we can do things in parallel which we are currently doing serially. One of the current challenges is maintaining what is know as coherence. Coherence can be lost by observing the state of a qubit as a result of the Heisenberg Uncertainty Principle.

The first half of my career has been marked by doing the same thing but making it smaller and smaller, and faster and faster. We've ridden Moore's Law far longer than I had personally anticipated. The question for the second half of my career is whether we will see Python's (Monty) Law: "And now for something completely different."