Monday, October 6, 2008


So apparently this gets read by more people than I expected. Had to delete some content from the last post, so as not to upset anyone. Sincere apologies to the parties concerned. Who knew that getting this blog read would be the opposite of what I wanted??

No, I'm just kidding, keep reading, and please comment if you feel compelled!

Saturday, October 4, 2008

Happy Sputnik Day!

Ok so it technically isn't anymore, since it was launched on October 4th UTC, and at this time, it is October 5th UTC. But it is still October 4th in the Antelope Valley, so I'm going to party if I want to! And by party, I mean write a blog post.

More progress on XA-0.1B this week. Ben has done a great job figuring out the noise issues and Dave's control code is good to go. Installing bandpass filters in the sensor lines reduced the amount of noise by an order of magnitude, and gave us the extra bits of resolution needed for a working rocket. Thus far the mods have been done to one engine, and we're working on finishing the others. We're redoing the wiring on the engine position actuators too, to try and reduce the noise there, along with putting EMI (ElectroMagnetic Interference) shielding on just about everything we can get our hands on.

We were initially planning on firing one of the four 500lb-thrust engines on the vehicle on Friday, but the airport staff were worried because our test stand looks like a piece of shit. It really isn't, but since it's a steel structure that's been sitting in the elements, it got all rusted. The blast deflectors are four angled steel frames, into which we put concrete tiles that ablate as the rather hot exhaust gasses hit them. However, on a couple of the pads, the hot gasses leaked around the edges of the tiles near the center and melted the frame slightly. This doesn't weaken the structure any, nor does it have any other adverse side effects, but it just looks a bit unsightly.

Jon and I went to the site on Friday to start getting things set up for the testing regime. We moved our nice Toshiba 46" 1080p HDTV out to the site to act as our "Window to the World". The test trailer does actually have a couple windows, but those are all pointing away from the test site, for obvious reasons (this TV also happens to make a great screen to watch Mythbusters and other such awesome-ness on). So instead, we have a Canon Vixia HV30 that will be streaming (and recording) live 1080p video of the rocket to our lovely TV inside. We also have acquired a Casio Exilim EX-F1 high speed digital camera for other photography. This camera can do up to 1200fps video, along with 1080p at 60fps and a whole slew of speeds and resolutions in between. The 1200fps videos are just cool to watch, especially when you record something like water falling or igniting isopropyl alcohol. It should also provide some really cool engine start videos when we start testing the 750lb-thrust engine. There is a third camera, an Aiptek A-HD video camera will actually be affixed to the vehicle, and probably pointed straight down to provide some onboard footage of the flights. The Aiptek camera is cheap enough (<$200) that we won't be too terribly saddened if it somehow gets harmed in the line of duty.

The goal for this upcoming week is to actually get our vehicle firing. We have enough done to at least fire one of the thrusters, as stated before, and by the end of the week, the entire rocket should be fully functional and ready for ground tests. The first few tests are going to be static firings, to ensure that everything is working as it should be. After that, we are going to try and fly the vehicle. For all of these tests, the vehicle will be attached to a tether, going from the nose to what is essentially a very high forklift. Until earlier this year, these did not count as suborbital flights, according to the FAA. Recently, they changed their regulations, and all of the activities described above count as flights. Since we're "launching" from an airport, there's even more red tape to clear, what with getting launch waivers and what not. Just for reference, XA-0.1b is not going to be capable of anything near suborbital flight. It has an endurance of approximately 45 seconds and the thrusters are optimized for low-altitude flights (ie. small expansion ratio). As it stands now, XA-0.4 will be the first vehicle capable of breaking the 100km barrier. That vehicle, however, is still only conceptual.

In other news, life in Mojave is still, well, life. Last weekend, Ben, Ian, and I went to the Friends of Amateur Rocketry (FAR) launch site to watch the Paul Breed's of Unreasonable Rocket test their latest vehicle. Unreasonable Rocket is a father and son team (both named Paul Breed) who are working on developing a hydrogen peroxide monopropellant rocket to compete in this year's Lunar Lander Challenge, out at Holloman AFB. The date is not certain at the moment, due to some top-secret activities going on at Holloman. The Paul's will be competing against eight other listed teams in the LLC. Their vehicle will be capable of competing in Level 1 of the competition (90 seconds+ of flight time). We went out there on Saturday to view their tests. Their first set of 3 tests were from about 3ft above the ground (the rocket was sitting on pylons) and they hovered for 5 seconds or so, till they throttled down for a soft "landing" where it was hanging on the tether. Their second set of flights included their first ever launch from the ground (and subsequent soft landing). Most of the tests were fully successful, but on one flight, they had a problem with their sodium permanganate catalyst feed, and flew only for a couple seconds. After fixing that problem, and having one more successful flight, they decided to call it a day. It was really cool to see what they're doing and how far they've come along, and I wish them the best of luck at the LLC competition!

Oh, and one last thing (geez, I'm getting to be almost as bad as Jon, with the length of these posts...). On Friday, as Jon and I were going out to the test site, I glanced back towards the flightline, and caught a few fleeting glances of this beautiful white twin-hulled aircraft. Scaled Composites Model 348 WhiteKnightTwo, A.K.A. VMS Eve, was sitting outside. Unfortunately, I didn't get a better view of the aircraft that day. Today though, as I was walking to the shop, I glanced over to my left and over the tops of the Scaled buildings, and two tails with "Virgin" emblazoned on them were visible. Between the buildings, you could see the wings, the PW308A turbofans without their cowlings, and the left-hand cockpit, with the "Galactic Girl" nose-art. Derek and I later went to Voyager for lunch, and from the restaurant, the aircraft was clearly visible. It's kind of weird, thinking that that is the aircraft that will be dropping SpaceShipTwo sometime in the future as it rockets off into space. Man, what a cool place this air/spaceport is!