This the first flight of the NOEXC Balloon Project program. It launched on 2014/11/16 at 11:50 EDT (16:50 Z) and landed at 13:21 EDT (18:21 Z) after 1h31m flight time.
Our objectives for this flight were:
- Working telemetry received during flight.
- Altitude above 15 km.
- HD camera recording.
- Magnetometer readings.
|Downlink:||145.700 MHz FM||RTTY 45 (170Hz Shift)||70mW|
The telemetry system consisted of an Arduino, 4 3400mAh batteries, a gps module, a magnetometer and enclosure.
The HD Camera consisted of a small hand held 1080p camera and 4 3000mAh batteries.
Weather projected for 2014/11/15 Launch was:
- Temp: 2 C (~36 F)
- Wind: 15 kph ( ~10mph) from SSW to NNE
- Precip: 4%
Launch location was from 40.377194, -83.059285 in Delaware State Park, Ohio. We had launched from this location prior to NBP-1 with no anomalies caused by the launch site location. We predicted that it would land somewhere in between Akron and Youngstown, Ohio, but it ended up landing south of Wadsworth.
Summary of Launch
The launch team woke up early on Sunday morning and headed down to the launch site. The predicted trajectory of the balloon was to follow a north easterly path so we launched at Delaware State Park north of Columbus Ohio. Most of the launch team arrived on time around 11:20 EDT. After setting up and mis-tying things a few times the telemetry was switched on at 11:32 and we started filling the balloon.
At 11:50 the balloon was released and had an initial ascent rate of 2.5m/s. The balloon easily cleared the trees and headed on a north-north easterly path. We did not realize it at the time but there was a slow leak which decreased the ascent rate linearly at 3.46m/s per hour. This linear decrease in ascent rate is what made the altitude plot rather like a parabolic trajectory.
Our entire telemetry system worked well and produced good reliable packets despite not having error detection on the telemetry. Signal strengths for the telemetry were around 59 to 59+40 for a majority of the chase. Mapview worked well and provided a great resource for tracking the balloon.
We tracked the balloon to a field where we were perplexed about its stationary location at 350m altitude. We didn't realize that this was the ground height above the WGS84 ellipsoid. Andrew walked out towards the location it was reporting and found it on the ground in a field.
Conveniently and as planned the balloon track was along the way home. We stopped in at a Burger King had some lunch and talked about the things we liked about the launch, how successful it was, what we'd like to change, and what kind of objectives/goals we'd like to shoot for in the future.
- We hit this issue where Firefox won't connect to a websocket from an HTTPS page when the websocket is not using SSL. In an attempt to work around this without modifying
mapview-sendat the last minute, I disabled SSL for the
nbp.noexc.org/mapview/path via CloudFlare Page Rules. However, I quickly came to realize that this won't work because we have HSTS enabled cross-subdomain. As a last resort, I moved mapview off to an entirely separate domain without HSTS and made
nbp.noexc.org/mapviewredirect to there. The lessons here are:
- Test even things that seem really simple to deploy (like a static mapview page), before the night before the launch.
mapview-sendto be able to work with SSL.
- Take note of our current elevation when chasing the balloon.
- CRC-16 of RTTY downlink
- Battery voltage in RTTY telemetry
- Display a ton of elevation data in mapview
- Callsign not in every RTTY packet
- gpsd integration with
mapview-sendfor local runs (maybe create
- Fix/test lookangle stuff in mapview
- Hydrogen leak
- Make launch checklist
- Include cleanup, and notify assistants of how quickly after launch we have to leave
- Food/fuel/coffee/sleep/proper clothing for weather
- Put batteries in before tying payload
- Ensure all know about hydrogen safety risks
- Hydrogen sensor
- Ensure batteries are isolated from one another (protect against fail-shorts)
- Low-power mode if battery is close to dying
- Figure out what uses most power
- Turn off expensive resources
- If in the last 10 packets, the balloon hasn't moved 25-100m, low power mode
- Separate system for experiments/last-minute "stuff"
- Andrew (KD8JKF)
- Ricky (N8SQL)
- Jimmy (KG4SGP)