SpaceX Dragon Panorama

SpaceX has a neat internal panorama up of their Dragon space capsule.

SpaceX Dragon capsule, internal iso/orthogrid panels and grid stiffened structure, forward/port view

Sears--Haack Body for Mini-Estes

We have a little company here in Dayton that does print on demand (Fabbr) with Makerbots. They specialize in printing RepRap kits, but I think I'm going to see if they can print me a little rocket to use with Estes mini-motors.
The 1/4 and 1/2 A motors are 13 mm in diameter and 44 mm long.

The first thing you need to print a part with these hobby printers is an stl file. I followed a some-what torturous route to generating one.
First I made a little python script to find the minimum volume Sears-Haack body that would fit a 13x44 mm cylinder. The bold black curve is the minimum volume body; it happens to have a length of twice the motor length.

As you can see in the script, I also dumped an svg file of that curve. This is easily imported into Blender. Then the svg curve must be converted into a Mesh, and the Spin method applied to generate the body of revolution.

I played with the number of steps to get a mesh that looked like it had surface faces with near unit aspect ratio (not that it really matters, but old habits die hard).

Now I should be able to add some fins and export an stl from Blender for my rapid prototyping friends to play with. The design goal for this rocket will be to have positive static margin with the motor in the rocket, but neutral or negative static margin once the ejection charge pops it out the back (that way it does a tumble recovery).

OpenFoam Now with Fedora RPMs

Well, I was pretty excited that OpenFoam was acquired by SGI, and they created a foundation to hold the copyrights for the project. That is good news for building a healthy open source community around the software. Looks like I jumped the gun with the install from source option I detailed back in November. If only I were a little more patient, I could have installed from rpms. The new release has lots of interesting additions. We live in exciting times for open source CFD.

McCain's Hangar Queen on Trend

Looks like McCain's Hangar Queen is on Norm's trend.

Entire Defense budget to buy one airplane

See the video; linked from Make. Related post on Roger Pielke's site.

Nuclear Politics Prior

One of the recurring themes of Climate Resistance (which I've mentioned approvingly before) is that the politics around the solutions proposed for climate change are prior to any consideration of the science of the environment (or the more interesting question Lorenz asked about the existence and uniqueness of long-time averages of the earth's weather).

This state of politics prior is unavoidable, and therefore not unique to the field of climate policy. I think this talk by Kirk Sorensen on the history of US breeder reactor development provides another good example.

The policy maker (Nixon in this case) picked the solution based on desired political outcomes (jobs and lucre for politically useful districts). "The Science" was merely a part of the marketing and public relations campaign for that choice. Dissenting scientific positions (the molten salt folks in this case) were suppressed with "Rickoverian dedication".

See this extensive remix for lots of info on LFTR.
"There's been a very bipartisan approach to scaring the public." Kirk Sorensen (~1:20 or so)
"The whole aim of practical politics is to keep the populace alarmed (and hence clamorous to be led to safety) by menacing it with an endless series of hobgoblins, all of them imaginary." H.L. Mencken

Setting up a project on Github

I've been an SVN user for a while, but it seems like more and more projects are going distributed version control systems like Git so I wanted to learn how to use Git. I found this crash course on Git for SVN users which provides a useful Rosetta stone, and this warning:

SVN is based on an older version control system called CVS, and its designers followed a simple rule: when in doubt, do like CVS. Git also takes a form of inspiration from CVS, and its designer also followed a simple rule: when in doubt, do exactly the opposite of CVS. This approach lead to many technical innovations, but also lead to a lot of extra headscratching among migrators. You have been warned.

This sounds a lot link Linus Torvalds' talk, WWCVSND: What Would CVS Not Do?

Github has a set of steps for setting up on linux. Git comes in the Fedora repos (and probably every other repo), so install is easy. A nice bit of documentation that comes with the install is Everyday GIT With 20 Commands Or So.

Since I already use password-less ssh to hop between the boxes in my little network, I didn't move my old public key as in the instructions. I created a config file in the .ssh directory containing these lines:
Host github.com
User git
Port 22
Hostname github.com
IdentityFile ~/.ssh/id_rsa_git
TCPKeepAlive yes
IdentitiesOnly yes
Where id_rsa_git.pub is the key I uploaded to github. Authenticating to github is then just:
ssh -T git@github.com
Then you accept their RSA key like you would for doing any other ssh login.

The next thing is to create a repo. Clicking through the instructions brings you to a page with several "next steps". Which for my example are:
mkdir FalknerSkan
cd FalknerSkan
git init
touch README
git add README
git commit -m 'first commit'
git remote add origin git@github.com:jstults/FalknerSkan.git
git push -u origin master
Which gives some output ending in something like: Branch master set up to track remote branch master from origin.

If you'd like, you can read up on the Falkner-Skan ODE at the viscous aero course on MIT's OCW:

• Local Scaling. Falkner-Skan Flows.
• Solution of Falkner-Skan Equation by Finite Differences

Now you have N problems

(10:40) It's not that regulators don't understand information technology, because it should be possible to be a non-expert and still make a good law. MPs and Congressmen and so on are elected to represent districts and people, not disciplines and issues.

That couple of sentences reminded me of a recent post on single-issue advocacy by Roger Pielke Jr. So, in that spirit, here's a fun word game: How applicable is Doctorow's criticism if you substitute "climate" for "copyright" below?

(22:20) But the reality is, copyright legislation gets as far as it does precisely because it's not taken seriously, which is why on one hand, Canada has had Parliament after Parliament introduce one stupid copyright bill after another, but on the other hand, Parliament after Parliament has failed to actually vote on the bill. [...] It's why the World Intellectual Property Organization is gulled time and again into enacting crazed, pig-ignorant copyright proposals because when the nations of the world send their U.N. missions to Geneva, they send water experts, not copyright experts; they send health experts, not copyright experts; they send agriculture experts, not copyright experts, because copyright is just not important to pretty much everyone!
Canada's Parliament didn't vote on its copyright bills because, of all the things that Canada needs to do, fixing copyright ranks well below health emergencies on first nations reservations, exploiting the oil patch in Alberta, interceding in sectarian resentments among French- and English-speakers, solving resources crises in the nation's fisheries, and thousand other issues! The triviality of copyright tells you that when other sectors of the economy start to evince concerns about the internet and the PC, that copyright will be revealed for a minor skirmish, and not a war. Why would other sectors nurse grudges against computers? Well, because the world we live in today is /made/ of computers. We don't have cars anymore, we have computers we ride in; we don't have airplanes anymore, we have flying Solaris boxes with a big bucketful of SCADA controllers [laughter]; a 3D printer is not a device, it's a peripheral, and it only works connected to a computer; a radio is no longer a crystal, it's a general-purpose computer with a fast ADC and a fast DAC and some software.

Full Transcript

Fedora 16 Install Notes

Notes on using the pre-upgrade method to go from Fedora 14 to 16 (yes, it's risky to skip a version). The reason for my upgrade is that Fedora 14 is now at end-of-life, I'd like to get FEniCS working, and some of the new spins look pretty cool.

One of the things I had to manually fix after reboot was the TexLive development repo (only 60% complete, estimated for Fedora 17). I had this activated to get the IJ4UQ styles to work.
yum remove texlive-release
rpm -i http://jnovy.fedorapeople.org/texlive/packages.f16/texlive-release.noarch.rpm
Manually remove some old conflicting packages (some from Fedora 12, yikes! I'm a lazy sys-admin).
List the repositories to make sure everything is pointing at the correct release version.
yum repolist
Sync things up.
yum distro-sync
I got this error: grubby fatal error: unable to find a suitable template. According to the forum I did,
mv /boot/grub/grub.conf /boot/grub/grub.conf.old
and then,
yum reinstall kernel
yum clean all && yum install texlive

The other problem I ran in to was with the hwloc package. I had to downgrade it to the 1.2.1 version, the 1.3 version seems to be missing the shared library needed by mpich and scotch.

McCain's Hangar Queen

Senator McCain's colorful statements about the F-22 are getting lots of coverage.

Another example of how flawed the Pentagon’s weapons procurement process is can be found in the F-22 RAPTOR program. When the Pentagon and the defense industry originally conceived of the F-22 in the mid-1980s, they intended it to serve as a revolutionary solution to the Air Force’s need to maintain air superiority in the face of the Soviet threat during the Cold War. The F-22 obtained ‘full operational capability’ twenty years later -- well after the Soviet Union dissolved. When it finally emerged from its extended testing and development phase, the F-22 was recognized as a very capable tactical fighter, probably the best in the world for some time to come. But, plagued with developmental and technical issues that caused the cost of buying to go through the roof, not only was the F-22 twenty years in the making, but the process has proved so costly that the Pentagon could ultimately afford only 187 of the planes -- rather than the 750 it originally planned to buy.

“Unfortunately, the F-22 also ended up being effectively too expensive to operate compared to the legacy aircraft it was designed to replace. It also ended up largely irrelevant to the most predominant current threats to national security -- terrorists, insurgencies, and other non-state actors. In fact, if one were to set aside the F-22’s occasional appearances in recent big-budget Hollywood movies where it has been featured fighting aliens and giant robots, the F-22 has to this day not flown a single combat sortie -- despite that we have been at war for 10 years as of this September and recently supported a no-fly zone in Libya.

“Politically engineered to draw in over 1,000 suppliers from 44 states represented by key Members of Congress and, by the estimates of prime contractor Lockheed Martin, directly or indirectly supporting 95,000 jobs, there can be little doubt that the program kept being extended far longer than it should have been -- ultimately to the detriment to the taxpayer and the warfighter. As such, it remains an excellent example of how much our defense procurement process has been in need in reform. We may fight a near-peer military competitor with a fifth-generation fighter capability someday, but we have been at war for 10 years and until a few months ago had been helping NATO with a no-fly zone in Libya. And, this enormously expensive aircraft sat out both campaigns.

“Moreover, as a result of problems with its OBOG (On-Board Oxygen Generating) system, which has caused pilots to get dizzy or, in some cases, lose consciousness from lack of oxygen, on May 3, 2011, the Air Force grounded its entire fleet of F-22s. While this grounding was lifted earlier this year, exactly why F-22 pilots have been experiencing hypoxia remains unknown -- but similar unexplained incidents continue.

“And then, there is the issue of the sky-rocketing maintenance costs to the Air Force in trying to sustain a barely adequate ‘mission capable rate’ for the F-22. Its seems that the ‘plug and play’ component maintenance features that were supposed to reduce costs for the Air Force over the life cycle of the aircraft doesn’t really play well. And, each time a panel is opened for maintenance, the costs to repair the ‘low-observable’ surface in order to maintain its stealthiness have made this critical feature of the aircraft cost-prohibitive to sustain over the long-run. Finally, it seems that the engineers and technicians designing the F-22 forgot a basic law of physics during some point of the development phase -- that dissimilar metals in contact with each other have a tendency to corrode. The Air Force is now faced with a huge maintenance headache costing over hundreds of millions of dollars-and-growing to keep all 168 F-22s sitting on the ramp from corroding from the inside out.

One thing is clear: because of a problem directly attributable to how aggressively the F-22 was acquired -- procuring significant quantities of aircraft without having conducted careful developmental testing and reliably estimating how much they will cost to own and operate -- the 168 F-22s, costing over $200 million each, may very well become the most expensive corroding hanger queens ever in the history of modern military aviation.

REMARKS BY SENATOR JOHN McCAIN ON THE “MILITARY-INDUSTRIAL-CONGRESSIONAL” COMPLEX

What bothers me most about the F-22 is not the maintenance problems, operational difficulties, or danger to air-crews. These require mere engineering fixes. What really bothers me is the damage these huge programs cause to rational risk assessment and national security.

"The reality is we are fighting two wars, in Iraq and Afghanistan, and the F-22 has not performed a single mission in either theater," Gates told a Senate committee last week.

Carlson ["We think that [187 planes] is the wrong number"], however, told a group of reporters earlier in the week that the Air Force was "committed to funding 380" of the fighters, regardless of the Bush administration's decision.

According to an Air Force official briefed on the Thursday rebuke, Gates telephoned Air Force Secretary Michael W. Wynne, who was on vacation at the time, to express his displeasure with Carlson.

The senior defense official said Carlson's remarks, reported Thursday by the trade publication Aerospace Daily, angered the Pentagon's top leadership, adding that they were "completely unacceptable and out of line."

Fighter Dispute Hits Stratosphere

That's not something that more money or more technology can fix.