- Pre-Launch Logistics
We successfully launched Launch Vehicle 2.3 (LV2.3) this weekend in Brothers, Oregon, at the Oregon Rocketry's Brothers Launch Site.
- Estimate elevation of hill by launch tower: 4900 ft MSL
- Launch control was at (GPS):
43 deg 47 min 55.4 sec 120 deg 38 min 54.5 sec @ 4459 ft
- Launch tower was at (GPS):
43 deg 47.652 min 120 deg 39.0889 min @ 4488 ft(2m accuracy w/10 satellites)
- Drogue was 16 paces and main was 34 paces away from LT, and between them was 32. Tim's paces are ~ 6 ft.
We gathered at Tim's house Saturday morning at 9:00am to pack all of our rocket bits: launch tower, antennas, launch control table, etc. We managed to pack it all into the back of Dave's pickup truck and in Dan's brother Bill's "Toy Hauler" - a large 5th wheel ATV carrier (thanks Dan! thanks Bill!). It was pretty amazing, actually: it was probably the fastest packing and smallest number of vehicles carrying rocket bits we've ever had since LV0. And, amazingly, we actually left on time.
We arrived in Brothers around 5:00pm, and in the last few hours of sunlight, managed to raise the launch tower and set up the antennas.
Saturday evening we stayed up late carefully prepping the avionics module and Dan's helicopter... but we - shockingly- even managed to get some sleep.
This was an "airframe only" launch, but we still managed to cram in a bunch of systems into the rocket:
- An Ozark Aerospace ARTS flight computer (hooked to the nose separation ring and the main chute line cutter
- a 2m backup system, which used a Alinco DJ-7T 2m radio hooked into a Atmel ATMega168 with a DTMF decode chip (also hooked to the NSR and 2nd line cutter).
- Keith's Telemetrum flight computer, with GPS (flown as payload only, with it's 900 MHz telemetry sending real-time telemetry and acting as a direction finder).
- An Olimex LPC2148 development board with SCP1000, MP3, and ADXS pressure sensors and ADXL3xx 2 axis accelerometer.
Sunday morning we got back to work 9:00am, did a final checkover of the avionics, attached the igniters, buttoned up the rocket, and took it to the launch tower.
We were ready to go by about 12:45pm, just in time the 12:30pm - 2:30pm waiver that Jeff of BORG called in for us. Again, surprisingly, we were ready to go, we just had to wait for a cloud break. After waiting about 30 minutes for a largish patch of blue sky, we turned on the avionics system(s), and cleared the pad.
One fun distraction was Dan's electric "T-Rex" helicopter. He strapped our spare camera and 2.4 GHz ATV transmitter to the nose and buzzed launch control and the launch tower. We had high hopes to catch the launch from the helicopter's perspective, but a loss of RC control made the 'copter crash and snap a blade. Next time!
Ian hit the "launch" button at about 1340 PDT in our Java "LaunchControl" software that he patched for this airframe-only flight, and it counted down and launched the rocket over the WiFi link to the launch tower. The rocket leaped off the pad on Pete Ekstrom's "N" motor with a eery blue glow. We heard two large reports, which later we figured out was the motor "chuffing" (overpressuring).
Short video from the ground
- Download: launch dk.avi (3.2 MB)
600 FPS High Speed Camera view of liftoff
- Download: launch 600fps.mov (3.3 MB)
- Download: launch onboard.avi (15.6 MB)
We lost track of the rocket as it went above the cloud layer, and we all desperately were hoping the parachute system would work. Keith lost telemetry for a a few seconds, but once he got it back, he was able to announce that we were falling slowly enough that we should be on the drogue.
And indeed, about a minute after that, the drogue and rocket were sighted.
Finally, the ARTS board fired the line cutters and the main chute came out. To top it all off, the rocket landed only a few hundred feet from the launch tower!
And just in time, too: about an hour after the launch, the winds whipped up and started blowing over tents and people, and it started to drizzle. We packed up in record time, and headed back to Portland.
All in all, a perfect flight!
- Thank you to Jeff and BORG for arranging the waiver.
- Giant thank yous to Liz, Casey and Alex for helping out so much.
- Double thanks to Alex Speaks of Zander Speaks Photography for taking such great photos (you can see http://speaksphotographic.com/psas for even more photographs of the launch).
Also thanks to:
All raw and processed data is here:
- 2009-05-31 data from arts.csv
- 2009-05-31 data from telemetrum.gnumeric
- Olimex data: lost due to lack of launch detect
TODO: Post graphs and final altitude and velocity numbers.
Using the calibration board behind the launching rocket and the high speed camera we are able to extract high quality data from the first few moments of flight.
Using the open source video analysis tool Tracker we are able to estimate the altitude, velocity, and acceleration of the rocket over the first 0.3 seconds of flight.
The large black and white blocks of the calibration board are 30 cm in height. A calibration stick is used to set the size of pixels in the video. Then the position of the rocket is tracked with the subpixel tracking feature in Tracker. The axis is set such that the motion of the rocket is assumed to be entirely vertical.
Data from the fight speed video shows a smooth take off.
Some noise seeps into the data now, but smooth acceleration is shown here.
The rocket comes up to about 10 g's almost immediately. Because of the double differentiation and the quantization noise in the image, the acceleration graph is very noisy, this one has been smoothed heavily.
- We need straighter fins
- better fin clamps? Screw holes so close together may torque fins?
- Bar between clamps and fins? Could use shims between clamp and bar.
- 2m backup system
- horizontal polarization of the bird feeder didn't reach the rocket on the rail (again)
- Better long wire antenna?
- Arm rocket by local HT at pad,
- or multiple (diverse) 2m uplink antennas
- Goal: verify 2m operation in flight.
- Here's the hand drawn schematic of the 2m backup system.
- Here's the backup pyro system source code for the AVR microcontroller.
- Avionics issues
- Really didn't like lack of feedback from all the different systems
- Need a post-launch checklist for what to do with the avionics
- Launch lugs
- Decide how to really do it. The bottom lug was seemed silly.
- Too hard to deal with: too tight! Tim: Make them looser.
- Need to think about sequencing how everything fits together.
- Things that were great
- Dan's brother Bill's toy hauler (thanks Bill! thanks Dan!).
- A dirt bike was awesome to have to explore the area and go back and forth from LC to the LT.
- The two canopies were enough, as long as we had the inside of the Toy Hauler.
- Possible August launch
- Won't be ready with Avionics
- Two months: pretty darn close
- October BRD launch
- Four months away
- Initial avionics: APS, 2m, pyro and ATV nodes (keep DVR?)
- Bonus: FC, IMU, etc.
- Two airframes for two launches?
- Yellow caution tape for coax to antennas.
The actual launch is taking place:
- Sunday May 31st, 2009 after 12:00pm and most likely before 3:00pm
- South of Brothers, Oregon at Oregon Rocketry's flight line (Click here for a map of coordinates +43.79942 -120.65086). For more explicit directions, see Oregon Rocketry's directions page.
- We must know you are coming ahead of time (email 'info' at 'psas.pdx.edu'), and attendees must sign both a PSU and Tripoli Rocketry Association liability waiver.
|8:00am||Saturday 5/30||Meet at Tim's house in Tigard, and pack up remaining rocketry supplies. Go over final checklists.|
|10:00am - 2:30pm||Saturday 5/30||Drive to Brothers, Oregon launch site (4.5 hour drive).|
|3:00pm - 7:00pm||Saturday 5/30||Set up in Brothers, with dinner.|
|Evening||Saturday 5/30||Final prep, marshmallow roast, star viewing.|
|10:00am - 12:00pm||Sunday 5/31||Final prep, watch BORG launches.|
|12:00pm - 1:00pm||Sunday 5/31||Target time for launch of LV2.|
|1:00pm - 3:00pm||Sunday 5/31||Recovery LV2, pack up, watch BORG launches.|
|3:00pm - Evening||Sunday 5/31||Return to Portland (4.5 hour drive)|
- You can camp out at the launch site, but you must observe OROC's site regulations.
- There are several hotels and motels nearby.
- Bart may have some places to stay.
Possible showers on Saturday, partly sunny on Sunday. It'll be ~ 60-70 during the day, but it's going to get awfully chilly at night. Here's the weather forcast.
|Who||In What||Other people?||With What|
|Andrew||red van||1, maybe 2||tools, pop-up tents, etc., 2nd Yeasu for backup|
|Dan||truck?||?||"Toy hauler", tools, rocket.|
|Dave||truck||Candace, 3-4 other people||Dan's trailer, with launch tower and other large things, and tools.|
|Glenn||car||No||HTs, arrow antenna, 2x SLA batteries, SWR meter, 2m birdfeeder.|
People looking for rides who have not yet found one:
People not caravaning:
|Who||In What||Other people?||With What|
|Bart||car||Keith, Jules, Ian Duffe||-|
|K||car||Paula, 1-2 others||-|
- Jay and Doug (by car)
- Steve and Louise (by plane, rendezvousing with Glenn)
- Morgan and Margaret and friends
- Nathan with parents