Ullage Motors

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If the reader is interested in the history of aerospace or rocketry, I’d like to recommend the book Saturn, by Alan Lawrie and Robert Godwin, Apogee Books, 2005 (ISBN 1-894959-19-4).  Lawrie is the author and Godwin produced the DVD that is included. The book is a comprehensive history of the Saturn V launch vehicle. 

Flipping through the book I happened to land on page 59 and a section on Ullage Motors.  If you have ever handled bulk liquids in drums or tankers, you know that there must be a certain fraction of the tank capacity left unfilled with liquid.  This gas space, or ullage, prevents rupture of the vessel by expansion of the liquid contents.

Ullage motors were used to get around certain problems associated with using liquid phase propellants in weightless conditions. The contents of a liquid propellant tank always include a volume of ullage.  In free fall it is possible for void spaces to form near the propellant transfer lines. 

Saturn V ullage motors were ammonium perchlorate solid rocket motors externally mounted on the lower part of the second stage.  Immediately after first stage engine cutoff, the first stage would separate and for a short time the upper stages would be in free fall.  To prevent transient fuel starvation problems during engine start it was desirable to force propellant to the bottom of the fuel tank prior to the engine start.  To accomplish this, a group of small solid rockets were fired to provide a bit of acceleration to force the liquid propellant to the bottom part of the tank. The eight ullage motors burned for 4 seconds and each generated a reported 22,500 lbs of thrust. 

Curiously enough, there are a reported 46 intact ullage motors in earth orbit.  The authors conclude that these remnants of the Proton 4 rocket represent explosion hazards. 

To the Moon!

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It is hard for most of us to tell but the US is in the early phases of a moon project.  It has adopted the same configuration of command module and lander as the Apollo program.  NASA intends to make a few exploratory missions lasting a week or so and then develop the capability for 180 day missions to the moon. This lunar “base” project is really a local rehearsal for a more ambitious manned Mars landing.  It is called the Constellation Mission. 

NASA has announced the development of two rockets for this mission- the Ares I and the Ares V.  The Ares I uses an in-line single solid rocket booster (SRB) for the first stage and a liquid propellant second stage to boost a 55,000 pound payload into low earth orbit.  Ares I is equipped with a emergency escape rocket in a tractor configuration analogous to Apollo.  As stated in the website, Ares I will be used to put the crew module in orbit for rendezvous with the ISS or cargo modules. 

The Ares V uses two SRB motors strapped to a liquid first stage engine in a fashion similar to the space shuttle. But the crew module will not be on this system.  Ares V is a cargo lifter and will carry 286,000 lbs of mass into low earth orbit.

NASA will be retiring the space shuttle system in a few years. The next man-lifter will be Ares I.  Evidently their faith in the SRB system is high.

That sucking sound heard around NASA these days is the sound of money being pulled from all over the agency and being dumped into this program. We’re going back to the moon, but with no real increase in funding.  Program managers are nervous. 

Wherein Gaussling Laments the Demise of Chemical Photography

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A sad day it will be when the last image is captured on a photographic emulsion. The transition from chemical photography to digital photography is well underway.  Indeed, it is clear by a simple visit to a big box store that the amount of shelf space given to film cassettes vs digital cameras & accessories is rapidly tipping in favor of the digital.  Consumer demand is well past the cautious early-adopter stage in its evolution.  Many people are several generations into digital photographic equipment. 

I own a low end Hewlett Packard Model P.O.S.  digital camera with a 4.1 megapixel chip.  I suppose I’d be happier with it if it still worked.  Even when it did work, it was a P.O.S.  As long as nothing moved, the image was sharp and the colors were true.  But given the slow shutter response, the slow shutter speed, and the heavy power demand on the battery, using it was a maddening experience. Evidently a capacitor has failed because the flash fails to fully charge. 

Printing is still a chemical process, one way or other.  Printing consumables like paper and inks/dyes are a major cash cow for all of the manufacturers of printers. 

I do not consider photocopier xerography to be strictly digital imaging.  I consider it to be a form of chemical photography because, despite the use of computer driven laser arrays and electrostatics in image formation, there remains a deep and intricate art in the chemistry of the toner composition.  I have actually done some color toner R&D and can attest to the high art required in that field.

Th’ Gaussling laments the demise of chemical photography, at least on the camera side, because of the highly advanced color chemistry knowledge that will inevitably be lost. Lost because skilled practitioners in the manufacture of color films will retire, labs and plants will be shuttered, and the use of color films will dwindle to low volume.  Soon, say 20 years from now, only eccentric purists and “hobbyists” will capture images on emulsions.  Drug stores will sell off their developing equipment to people who drive VW Beetles in Guatemala and fill the space with racks of diabetic candy, NASA diapers, and $4.99 DVDs. 

Soon, the experience of dodging a poorly exposed image under the projector, swishing print paper in developing solution under red light, and experiencing the magic of seeing an image appear will be lost to future generations.  The smell of acetic acid and the darkroom clutter of wet film hanging from string will be but a distant memory of the “old ones”. 

When I get to the nursing home I’ll regale my fellow geezers and codgers with harrowing tales of nights spent outside at the telescope shooting time exposures with hypersensitized Tri-X.  They’ll nod off in boredom and I’ll switch on a Star Trek rerun and fall into a deep slumber while Kirk and Spock contend with the Tholian Web.  ZZzzzzz.

Infotainment, Chemistry, and Apostasy

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In the normal course of things Th’ Gaussling gives school chemistry talks or demonstrations a couple of times per year and until recently, I had been giving star talks at a local observatory more frequently.  The demographic is typically K-12, with most of the audience being grades 3-8.  From my grad student days through my time in the saddle as a prof, I was deeply committed to spreading the gospel of orbitals, electronegativity, and the periodic table. I was convinced that it was important for everyone to have an appreciation of the chemical sciences.  I was a purist who knew in his bones that if only more people were “scientific”, if greater numbers of citizens had a more mechanistic understanding of the great intermeshing world systems, the world would somehow be a better place. 

In regard to this ideology that everyone should know something about chemistry, I now fear that I am apostate.  I’m a former believer.  What has changed is a newer viewpoint based on some observations.  

Chemical knowledge is highly “vertical” in its structure.  Students take foundation coursework as a prerequisite for higher level classes.  Many of the deeper insights require a good bit of background, so we start at the conceptual trailhead and work our way up. But in our effort to reach out to the public, or in our effort to protect self esteem, we compress the vertical structure into a kind of conceptual pancake.  True learning, the kind that changes your approach to life, requires Struggle.

What I find in my public outreach talks on science- chemistry or astronomy- is the  expectation of entertainment. Some call it “Infotainment”.  I am all in favor of presentations that are compelling, entertaining, and informative.  But in our haste to avoid boredom, we may oversimplify or skip fascinating phenomena altogether. After all, we want people to walk out the door afterwards with the answers. We want Science to be accessable to everyone, but without all the study.

But I would argue that this is the wrong approach to science.  Yes, we want to answer questions.  But the trick is to pose good questions.  The best questions lead to the best answers.   People (or students) should walk out the door afterwards scratching their heads with more questions.  Science, properly introduced, should cause people to start their own journey of discovery. Ideally, we want to jump-start students to follow their curiosity and integrate concepts into their thinking, not just compile a larger collection of fun facts. 

But here is the rub. A lot of folks just aren’t very curious.  As they sit there in the audience, the presentation washes over them like some episode of Seinfeld.  I suspect that a lack of interest in science is often just part of a larger lack of interest in novelty.  It is the lack of willingness to struggle with difficult concepts.  But that is OK.  Not everyone has to be interested in science.

Am I against public outreach efforts in science?  Absolutely not.  But the expectation that everyone will respond positively to the wonders of science is faulty.  It is an unrealistic expectation on the 80 % [a guess] of other students who have no interest in it.   I’m anxious to help those who are interested.  It’s critical for students interested in science to find a mentor or access to opportunity.  But, please God, spare me from that bus load of 7th graders on a field trip. 

What we need more than flashier PowerPoint presentations or a more compelling software experience is lab experience.  Students need the opportunity to use their hands beyond mere tapping on keyboards- they need to fabricate or synthesize. You know, build stuff. 

It is getting more difficult for kids to go into the garage and build things or tear things apart.  Electronic devices across the board are increasingly artifacts of microelectronics.  It is ever harder to tear apart some kind of widget and figure out how it works.  When you manage to crack open the case what you find is some kind of circuit board festooned with cryptic resin-encased devices. 

The emphasis on information technology bypasses the fact that we still need to build things.  Kids need to develop their mechanical skills. And they do that by building things. 

Urinetown- Hail Malthus!

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When a friend said he had landed a part in a local production of the musical “Urinetown“, I did what most people do.  I shook my head slightly as if to dislodge some interfering muck from my ears and sputtered “Wha, what?”.  I could tell he was weary of this response. To his credit, he politely explained some of the highlights of the show. 

Urinetown is a musical farce about a future with a water shortage so severe that even the flow of urine has to has to be regulated.  Originally slated to open on 9/11/01, the opening was delayed for a rewrite.  In the story, bald political corruption and dastardly corporate greed work together against a Gotham City backdrop to monopolize public toilets and exploit the need of the masses to … pee.  When urinating in the bushes is outlawed, only outlaws will urinate in the bushes.  And if caught, violators are summarily arrested and taken to Urinetown by officers Lockstock and Barrel where they suffer the consequences of their misdeed. 

Officer Lockstock serves as both constable and narrator in this self-referential satire about the collusion of business and government.   UGC (Urine Good Company) has a government sanctioned lock on the “Amenities”, public pay toilets, and enforces their use through corrupt police on the take.  But when the government raises the fee for the use of an Amenity on behalf of their corporate paymasters, ostensibly to pay for continued “corporate research”, a rebellion begins and ends finally with a Malthusian note.

I will refrain from disclosing further details about the story.  I will say that I thoroughly enjoyed the show and heartily recommend it to friends and colleagues. 

Friday Link-o-Rama

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The Russian cruise missile submarine Kursk went down in the Barents Sea, killing all aboard.  The first link has interesting pictures of the remains of the sub after it had been recovered. The second has interesting background information.

Need a spectrograph for your backyard telescope?  Check out this cool instrument from SBIG.  The good folks at Brookhaven have a table of nuclides online as well as a “Nuclear Wallet Card“. Golly, maybe one day we’ll have electricity too cheap to meter…

Check out the Deep Space Exploration Society- DSES.  They have resurrected a pair of dishes for the purpose of amateur radio astronomy.  They have been doing a sky survey at 1420 MHz.

Looking for something more refractory than the head of Karl Rove?  Check out FiberFrax.

Where are all the BA/BS organic chemists?

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Over the years I have interviewed many hopeful candidates for a position of entry level BS/BA bench chemist in a synthesis lab.  Recently, I have interviewed a couple of candidates for synthesis chemist position and have refreshed myself with the challenge. 

It is surprisingly difficult to find and hire a decent candidate for position as a synthetic chemist at the bachelors level.  In fact, I am having trouble finding fresh BS/BA graduates that can show me the mechanism for the acid catalyzed hydrolysis of an ester, or can suggest a reagent for the reduction of benzaldehyde to benzyl alcohol.  These are fundamental transformations and a BA/BS in chemist should be able to go to the board and noodle through a little bit of arrow pushing.

Most of the candidates sent in by our favorite temp agency are analysts either by temperament or by experience.  Granted, analysts may be the meat and potatoes of the temp chemist trade.  But what astonishes me is the small number of candidates out there with more than 2 semesters of organic chemistry and an even smaller number with any inorganic lab experience at all. 

In previous searches we have looked for BA/BS people from an ad in C&EN.  Rarely did we find that students had taken an advanced organic class/lab, let alone an organic qual class.  I know that such classes are offered out there.  Are all of these bachelors level students who take advances coursework going to grad school or med school?  Maybe most of them are.

As a former supervisor of undergraduate research, I am tickled pink that bachelors students are getting experience with advanced equipment, but we still need to graduate people who can make a target molecule and fish it out of a product mixture.  I’m glad that Bobby or Suzie can do capillary electrophoresis or use a peptide synthesizer to make a decapeptide.  I just hope that a few students are learning how to take a substrate through at least two steps of a literature procedure synthesis and then purify by fractional distillation or a recrystallization.  Furthermore, I hope that chemistry departments are still hiring an occasional mainstream organic chemist or inorganic chemist who can pass along lab techniques.

Perhaps the bachelors organikkers are drawn to grad school for advanced education.  That is what I did.  But I’m still shocked by the number of bachelors level candidates I see that show very little retention of organic concepts, apparently the result of disuse in their junior or senior years. 

Part of this problem might be geography as well.  My region does not have the industrial legacy that other regions have.  Perhaps the situation might be different in NJ, CT, or TX. 

Sorry. I’ve filled the position, so don’t send a resume.

A380 Evacuation Test

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Here is a link showing the evacuation of an A380. This airplane disgorged 873 people in 77 seconds.   So I’m thinking, what if you don’t have a planeload of orderly Germans who know how to get moving? What if you had a load of fat, jetlagged American touristas with expensive stuff in the overhead storage? You’d never get out of that airplane alive because some nimrod would have to get up and grab something out of the inside of a zipped bag, dooming everyone to incineration.

When one of these meat wagons eventually goes down, it is going to be like a small town got wiped out.  Like a screaming village falling out of the sky.  In a water landing, this thing is going to cartwheel like a drunken gymnast when a wing dips and grabs the water, and from the parts of the fuselage that shredded open will fly whole rows of horrified passengers, some still gripping their bags of pretzels.  The cabin sections will come to a halt and sink like a stone. 

Oh.  Well, I guess most of them do that.  Regardless, it ain’t gonna be pretty.

Here is a test of the braking system of the A380.  Ever wonder what happens when a big turbofan throws a blade?  The folks at Rolls Royce released this video of a test.  P&W released one as well.  This is what you try to avoid when working around jet engines.