Levitt, Freakonomics

Seth Levine influenced me to 'read' Freakonomics. I actually used OverDrive to listen to the book while working at night. I didn't retain as much as I would focussed purely on a book but I didn't want to completely waste my nights working.

The best part of the book for me was that they would give some surprising or shocking conclusion to something and then they would describe how it came to be. Chapters 1, 2, and 5 were enlightening to spectacular while 3, 4, and 6 were just interesting to me. Chapter 1 was about incentives and cheating, how incentives can go wrong, who cheats, and how cheaters might be caught. Chapter 2 was about information so they detailed a key time in the bringing down of the KKK and considered real estate agent performance.

Do parents really matter? That is the question in Chapter 5 and data shows that the amount of time kids spend watching TV doesn't positively correlate their standardized test scores. In fact, a list of 16 or so issues are considered and I was surprised at others like regular trips to the museum or parents reading daily to the kids don't positively correlate.

Pika Pika

The video below is the first I've heard of Pika Pika. Interesting; creative.



Some of the stuff is clearly flashlights but other stuff looks pixelated - to the point that it seems like the photos were edited with a Koala Pad on a C64. Fun idea though!

We gotta go to the crappy town where I'm a hero.

I bumped into the Hero of Canton clip from Firefly tonight and it gave me some good laughs. Of course, if you aren't a Firefly fan, then it's probably not so fun.



Well done, Joss and crew - that was some great stuff you all created.

That's just freaky.

Read this Wired article: Harvard Physicist Plays Magician With the Speed of Light.

... recently she shot a pulse into one [Bose-Einstein condensate] and stopped it — turning the BEC into a hologram, a sort of matter version of the pulse. Then she transferred that matter waveform into an entirely different BEC nearby — which emitted the original light pulse.

Awesome... and freaky :)

To find out what you don't know, you have to do

Google Alerts informed me of this insightful article. The whole thing is interesting, but the clip that jumped out at me was this:

That's one of the big things I've learned over the past three years at Masten Space Systems - you never know how much you really don't know until you try to find out.

We often talk about the importance of knowing what you know and don't know, but sometimes we forget how to discover what we really don't know. It isn't just about thinking and analyzing.

Solar Power Options

A few years ago, my neighbor offered me solar panels that he wasn't using. I thought that was cool and I looked into what I'd need so I could use them. At the time, I'd need some stuff and batteries - that batteries are more important than the other stuff because they are so expensive.

If the neighbor was still there and was still offering the panels, I'd take them now because it sounds like you don't need batteries now. My understanding, based on a brief discussion with BB, is that Xcel will buy any excess electricity generated so there is no need for batteries any more. Cool - too bad the neighbor moved!

I just read about a new option today on Wired. I was actually enjoying this excellent article, Thanks to Google's Tools, I'm the Most Efficient Time-Waster Ever and then I spotted this article, Selling Homeowners a Solar Dream. Pretty interesting stuff: this new company puts everything in place and you agree to buy your power from them at a fixed rate.

Citizenrē - take a look - interesting.

XO Production Starting / Buy One Get One

I signed up to buy an XO a year or two ago and the time is finally getting close! Production runs of the XO start this month and supposedly we'll be able to buy an XO sometime around Nov 12. To buy an XO, you pay $400 which results in you getting one for yourself and giving one to a child somewhere. More info here.

Yes, they need medicine, food, etc. but help them bridge the technology gap too.

Launch Log 2007.11.03

We only had two launches, but both were great flights. Our first was an Estes Mean Machine, we call it the Rainbow Machine, on an Aerotech E15 motor. It took a second for the rocket to lift off but it then flew straight and higher than I had imagined it would. Our second flight was a Level 1 certification attempt using the Bullet (booster only) on an Aerotech H128W motor. The Bullet flew straight and deployed perfectly at apogee, but had a rough landing invalidating the certification attempt.

The unfortunate landing: by catching the tip of the fin here, it cracked the fin root and will require the joint be soaked in thin epoxy before flying the Bullet again.


Shanelle caught this pretty launch while we were there. This is not one of our rockets but it sure is a nice picture so I'm posting it.

installing mysql and sshd on Ubuntu 7.10

One of my programmers asked me how to install MySQL and SSHd on Ubuntu 7.10. I assumed that it would be Applications -> Add / Remove -> MySQL and SSHd. I learned that Ubuntu 7.10, out of the box, doesn't have the repositories configured for these servers and also that there is a little different approach for services.

Here's what I ended up doing, and I like it:

System -> Administration -> Software Sources
    Ubuntu Software
        X Canonical-supported Open Source software
        X Community-maintained Open Source software
        X Software restricted by copyright or legal issues
    Third-party Software
        X http://archive.canonical.com/ubuntu gutsy partner
    Close

Applications -> Accessories -> Terminal
    sudo apt-get install mysql-server
    sudo apt-get install openssh-server

Good stuff.

von Braun, Space Frontier

I definitely read this book again. von Braun covered details about every aspect of space flight at the time: the reason for the countdown starts the book, details about the various types of escape rockets and how they work are covered, different styles of pumping and pressurizing liquid fuels and discussed, and all kinds of other stuff.

Rocketplane Global... XCOR Aerospace...

The two companies that have lingered on my mind since the X Prize Cup have been Rocketplane Global and XCOR Aerospace. I hope that both companies become tremendously successful, but I spend a lot of time wondering if either of the companies can find success.

On the surface, XCOR seems to me to be the most likely company in the new race-to-space to succeed. The things that I see on the surface is that they have a couple rocket planes that actually fly with the rockets, they have developed and patented technologies critical to improving the engines (and others are using the technologies), and they aren't publicly speculating / promising when flights will be available.

XCOR's Xerus should be impressive if they can pull it off. Having built and flown the EZ-Rocket 20+ times and built and flown the next generation, Rocket Racer, it seems that they are evolving and iterating fantasticly.

Rocketplane has all the right people and just dumped the Leer that they've been working on for a couple years. To me, that says that they have no hope - sounds just like a dot-com run by rich kids. On the other hand, they are contracting almost everything out except for the stuff that is truely their core competency.

No matter what happens - those people in those companies are doing some way cool stuff. Good luck to all - yes, I think that it takes some luck to make a successful company.

The purpose of the countdown is to:

Assure maximum safety for flight crews (if any), ground crews, and equipment, while the vehicle is prepared for flight.

Avoid wearing out critical flight or ground equipment by activating it too long before launch.

Enable the launch director to launch at an exact instant - corresponding, say, to a favorable position of celestial objects, or to requirements for orbital rendezvous.

Synchronize launch preparations with supporting operations, such as the readying of radars and tracking cameras, or the setting up of road blocks near the launch site.

- Dr. Wernher von Braun

I think that for many hobby rocketeers with kids, that last bit may need to be changed to, "Synchronize launch preparations with supporting operations, such as the rounding up of the kids, the covering of the little ears, readying of radars, ...".

Close to a Thor Simulation

Entering rocket details into RockSim is not my favorite task. Fortunately for me, I almost finished creating the Thor in RockSim - that means that I'll be able to start running simulations soon.



As for construction: Greg M provided the drill press and drilled the holes in the aft centering ring last night for the motor retainer. Joe at HobbyTown helped me find another forward centering ring since one of the rings provided with the kit was consumed by the motor retainer. I expect to set all the centering rings today and hope to do some glassing with Warren on the airframe tomorrow.

Clary, Rocket Man

i borrowed Rocket Man from the local library with the hope of learning a bit about Robert Goddard. The book was pretty difficult to read, so I don't expect to ever read it again. The biggest problem was that the author bounced around in time so it was confusing about what had happened versus what was going on at the time. Another confusing bit was that the author used different names for the same people, but there were so many names in the book that it became a blur.

A particularly interesting bit in the book was that they dispute a lot of Goddard's claims. Goddard was certainly an intelligent visionary, but he was exclusive and when he found people that were likely smarter or more qualified he either convinced them to work on his team or he shunned them. Goddard received more publicity than any other scientist, but he never published in scientific journals.

Launch Log 2007.09.22

We had 7 launches on this awesome late-summer afternoon. We pulled out the Renegade which hasn't flown in a while, melted the Stingray, and broke the fin on the Purple Rhino - again. Spencer wanted to fly the Firestreak SST but it has a broken fin from little boys playing with rockets so we'll have to wait for a replacement part.

• Firehawk | 1/2 A3 | straight flight, higher than usual on 1/2 A3, drifted in recovery to land 100 yards from pad


• Renegade | C6 | Isaac did most of the prep, some weather cocking, drifted in recovery to land 120 yards from pad


• Army Man | B6 | impressive flight on a B6; no weather cocking but drifted a lot in recovery; landed about 200 yards from pad - bounced in a parking lot


• Stingray | 1/2 A3 | Spencer thought about prep'ing the rocket, weather cocked just enough to land close to pad on streamer recovery


• Purple Rhino | 4 x A10 | beautiful flight - love this rocket; no weather cocking; light wind so landed pretty close to pad


• Firehawk | 1/2 A3 | neighborhood kid joined us and did the prep; chute got stuff in ejection so motor ejected; no damage to rocket (other than lost motor retainer


• Stingray | 1/2 A3 | the ejection charge blew the nose-cone off the rocket and melted / deformed the top 60% of the fuselage; fuselage and nose-cone both recovered but rocket is damaged beyond repair because of the deforming of the fuselage

Before the final Stingray flight, we attempted to launch Mighty Mouse 2. I didn't have anything to use for flash-in-the-pan ignition, so we tried using solar igniters. After 3 attempts of getting rocket to pad, count-down, fail, check connection and for shorts, we gave up. We're thinking we need to build or buy a bigger launcher (one that uses a bigger battery anyway).


Spencer can't hold down the launch key, so Isaac holds the key and Spencer pushes the button.


Team work - and the rocket lifts off. Note that it is the person pushing the launch button that does the count-down.


Spencer finishes off his launch by doing his own retrieval. Well done, Spencer.

Bullet Ground-Testing

I've been reading a lot lately that you need to always ground-test to make sure that the charge can separate the loaded rocket. I had actually planned to fly the Bullet without ground-testing but I'm ready to fly the Bullet and the next available date isn't until November so ground-testing sounded kinda fun.

I prep'd the rocket (without an engine) and fed the wire for the Main ejection canister through the static port hole. Some people, so I'm told, do their ground-testing using a tube taped to the static port hole and they suck on the tube and then when they release, the AV bay represurrized and the computer fires the charges. I manually tested the computer separately a few days ago using it's built-
in test sequences and am just testing the separation in my ground-testing here.

Isaac thought that the test failed; he knew that the rocket wasn't going to launch but he thought that the chute was supposed to open. I used the canisters that I built a couple weeks ago and calculated that I needed about 2.5 g of FFFFg black powder for the ejection charge. A failure would have either been the whole upper section shredding from too big a charge or the nose code not popping out with force from too small a charge. Looks to me like the 2.5 g was just right.

Launch Log 2007.09.20

We met up with some friends at the park at 6p to play and launch some rockets. We had 5 launches and ended the evening by losing Mighty Mouse - yes, the original. Very sad.

By the time we all ate, it was after 6:30p - that means the sun was about to go down. The field had been in use by a bunch of soccer teams, so we weren't just waiting to finish eating. We performed a rapid setup and prep on the Firestreak SST and launched it for a nearly perfect flight on a 1/2 A3.

The second flight was the Firehawk on an A3, but we had intended to use a 1/2 A3. With dusking coming and a bit of a break, we needed to keep landings close to the pad and that meant lower flights. The Firehawk is a great flyer and it went out of sight on the A3. There was almost no weather cocking so a long walk crossed my mind; fortunately, the chute only opened about 70% so decent was quick but not destructive.

Third flight was the Firestreak SST again but this time with Sam pushing the button. Another great flight on a 1/2 A3 - Spencer loves his rocket and set it asside with the intention of us launching it again right after launching the Stingray. The Stingray was unexciting on a 1/2 A3 - just too small to see in the near dusk conditions.

The Firestreak SST wasn't ready for a flight yet, so I loaded up Mighty Mouse for a flight on a C6. What was I thinking? Bad choice - so long Mighty Mouse. After spending some time looking for Mighty Mouse, we cleaned up and went home.

Recovery Canisters

When I built the Bullet, I went with a common canister for storing the recovery charges: a PVC cap attached to the AV bay. Now that I've watched many people prep for flights, I've decided to switch to these Polyethylene tubing-based canisters. I'm hoping to do ground tests tomorrow for separation for main chute deployment so I made some canisters today.

In the pictures above, you can see the first couple steps I use. Since the glue takes a moment to set and the ROL article is light on details on technique, I decided to record my steps for future reference. I found it easiest to put a partial ring of glue around the bottom before involving the e-match. There would be just a little gap open to get the e-match in. After the partial ring set, I put the e-match in and put just a small drop of glue in to hold the match and then let that set. Finally, I'd put in the final bit of glue and fill it out at the bottom.

The reason for the multiple steps was that putting too much glue in at once made it too difficult to manage the e-match. For the separation tests tomorrow, I'll need to add 3g of black powder to the canister and cap it with masking tape but the hard part is done now.

Launch Log 2007.09.09

Mom and I briefly attended the Tripoli Colorado commercial launch on Saturday (2007.09.08) but we didn't launch anything. We got to see an impressive flight on a SkyRipper K motor - that was the first flight I'd seen on a hybrid (other than a couple Alpha Hybrid test flights that blew up the rockets). I attended the Tripoli Colorado research launch on Sunday (2007.09.09) for about 5 hours and got to see some static tests, more Alpha Hybrid tests (yes, again, they destroyed the rocket), and some big launches on home-built motors.

When we got home from our trip in the mountains, we all went over to the field by our house and launched a few rockets of our own. The first flight was Spencers new purple rocket: the Firestreak SST. The Firestreak SST was purchased to replace Spencer's previous favorite: the 'silver nose' Outlaw which finally broke a fin and is no longer flyable. The Firestreak SST used a A3-4T for its first flight and flew great but recovery was not ideal: it uses a streamer for recovery but the streamer didn't appear to slow the rocket much.

Our second flight was Isaac's new Firehawk. Isaac built and put the decals on the Firehawk himself but I assisted with the glueing. Isaac even tied the shock cord on. We flew the Firehawk on an A3-4T but recovery here was also a bit of a problem: chute didn't open right and got tangled up. We'll have to watch it closely on the next flight - perhaps we didn't pack the chute good enough on this first flight.

It was a bit windy: we had to tilt the launch rod quite a bit to keep the rockets coming down within walking distance.

We flew Mighty Mouse on a B4-2 and Army Man also on a B4-2. Might Mouse landed in a pine tree but was recovered and had no damage. Great straight flight and drifted a bit in recovery. Army Man landed behind the school; Shanelle was hoping it was on the school but the boys recovered it without trouble. It flew great on the B4 with very little weather cocking (which is why it landed so far away :) ).

Launch Log 2007.09.01

We launched at the NCR North Site which is in the Pawnee Grasslands. The launch ceiling was around 20,000 or 25,000 feet but none of our rockets were sent to even 1/10th that altitude today. We launched the Purple Rhino, Migthy Mouse, Army Man, and then Mighty Mouse 2.

Our first flight was a flash-in-the-pan ignition of the Rhino. It flew 4 A10-3T's which carried it high and straight even though only 3 of the 4 motors lit. The second flight was the Mighty Mouse on a C6-7. The 7 second delay was nice because that kept the Mighty Mouse pretty close to the pad even though it was a nice, high boost. The third flight was Army Man with the split set for the center of the rocket. Past flights of Army Man suggested that it was heavy or not aerodynamic so we used a C6-3; I'm pretty sure it hadn't hit apogee when the chute opened. We had to walk quite a ways to recover Army Man but we did find it. Finally, we launched Might Mouse 2 for the first time. We used 3 A3-4T's with a flash in the pan (but the pan in this case was a Cherry Coke can rather than our usual ceramic dish). I was worried that the flash wouldn't light all motors because the can wasn't as close as I usually like but all motors did light and it was high and straight.

We saw a couple dozen other flights. There were quite a few problems - more than I've seen at a public launch. One rocket got tangled on the rod, caught fire, and then knocked the launch pad over. Two rockets went unstable immediately and landed in the viewing area. Quite a few recovery failures; this one in particular was interesting:

This bowling pin and ball was pretty and flew nicely, but recovery failed completely. It went ballistic and fortunately landed quite a ways away from the launch line because was a big, fast impact.