In this 2nd Edition of SPACE Camp, learn all about Telemetry. What is it, how do you use it, and what are the options for HAB weather balloons?
SPACE Camp Lesson #1 - Nozzle Lift
Quick Launch Inflation System for High Altitude Balloons
Assembly Includes:
- CGA-580 regulator to adapt to standard Helium tanks
- 25 ft. High-Pressure Hose
- Quick-Detach Hose Adapter
- Quick-Detach Balloon Adapter and Fill Nozzle (for 3cm Neck balloons)
Benefits:
- All the parts required to attach to a CGA-580 helium tank and fill your balloon!
- Lightweight and durable design
- Saves time and hassle during the fill process
- Quick-disconnect feature for measuring Nozzle Lift during filling to confirm accurate helium volume and lift
- Nozzle easily adapts to balloon during filling
- 25' Long Hose Allows balloon and helium tank to be separated during filling
- Provides a quick attachment point for the Payload Attachment Line (P.A.L.) [COMING SOON] - No knot tying or zip-ties required!
- Flight-tested to be rugged and safe
Specifications:
- CGA-580 Regulator for Safely Attaching to Helium Tank (Warning: Never use a helium tank to fill a weather balloon without a gas regulator. The gas coming out of the tank can be in excess of 2000psi, even if you "only" crack the valve open a little)
- Pressure-Rated 25'L Hose and Fittings
- 40-75CFM maximum fill rate (We do not recommend filling at maximum flow)
- Designed for 3 cm (up to 1500g Kaymont/Totex balloons) or 5 cm (2000g and 3000g Kaymont/Totex balloons) throat diameter balloons
Product Description:
Finding a regulator that has the correct attachments required can be an issue (and expensive), and by the time that you have purchased all the required regulators, hoses, fittings, and adapters from various sources, you have invested a substantial investment of your precious time and money to piece something together that you hope works, based on some article that you read online. Not to mention that after you have all the pieces you need, you still have the hassle of attaching the balloon to the fill device, disconnecting and re-attaching it several times to obtain accurate Nozzle lift measurements during fill, and finally tying off the balloon throat in a safe way that won't leak and won't risk a premature burst at a low altitude. Sound familiar?
Filling up your weather balloon can be one of the most time consuming and expensive steps in the entire high altitude balloon launching process...but it doesn't have to be!
With the Quick Launch Inflation System, you receive all the pieces you need to make the weather balloon inflation and launching process a SNAP - literally! With built-in snap quick-disconnect adapters, you can easily snap your balloon on and off the inflation nozzle during filling, and quickly attach it to the Space-P.A.L. (Payload Attachment Line) to reduce the time to launch, as well as remove room for error with tying knots, attaching zip-ties or tape, and tying off the balloon.
Available standard for 3-cm neck diameter balloons (e.g. up to a 1500g Kaymont/Totex design), and available for larger neck sizes upon request.
Instructions on how to operate the Quick-Launch inflation nozzle can be found here.
Doubling Down on Doge - Engineering Flight Test (EFT) 4
Our fourth Dogeship launch went up over Virginia this past weekend, racking up a second successful flight! The Doge appears to have attained an altitude of roughly 65,000 feet with a flight time of one and a half hours. The winds were light on launch day, so the total distance traveled was roughly 26 miles through the Shenandoah Valley. A more thorough post of the flight will come in the next few weeks after we've gotten a chance to analyze the data.
For this launch we attempted to fly two video cameras - one knockoff Go-Pro which was cheap enough to be considered expendable, and our trusty Canon digital camera which was space qualified on EFT3. Unfortunately the videos all terminated after around 25 minutes of flight. The Canon, mounted on the outside appears to have frozen. The Faux-Pro was inside the Doge and overheated due to the heat of the hand warmers. One major observation was the recurrence of a high frequency rolling motion of the payload combined with a downright violent spinning of the entire system during the climb. Once we post the video this will become immediately apparent - it'll make you sick!
Many more lessons learned on this flight, but the big success was the second flight of the telemetry tracker, and the first flight with our enhanced mission code, which is just begging for a future blog post. This system is smart enough to detect launch and land, and has a number of fault codes that trigger various actions to attempt to provide locations in the event of an in-flight emergency. More on this one to come soon.
The Doge has Landed! - Engineering Flight Test (EFT) 3
Date: 14 March 2015Equipment: DS Rev 3 (aka Dogeship-3)
Launch: Greensboro, NC
Landing: Warrenton, NC
Time of Flight: 89 Minutes
Distance Travelled: 91 miles
Burst Altitude: TBD (~61,000 ft)
After our first successful balloon launch with EFT-2 (still to be recovered), plans for EFT-3 were immediately underway with great enthusiasm and vigor. The biggest planned improvement (aside from launching in a warmer location) to the hardware arsenal for EFT-3 would aim to prevent the payload from getting stuck in the tree, by means of a “cut-down” circuit.
The thought of the cut-down circuit would be to attach the payload to the parachute via a single string, and activate a mechanism which would sever that attachment and allow the payload to fall from the tree while the parachute remains suspended in any branches. The original concept would use the phone as the activation mechanism. By playing an audio signal (none other than the Star Spangled Banner for us) from the phone, it would trigger a signal in a circuit and trigger a relay to dump current from a small battery through a piece of Nichrome wire. The hot Nichrome wire would melt the attachment to the parachute, and voila! The payload would fall from the tree. Unfortunately, the cut-down circuit was abandoned last-minute due to insufficient time for prototyping and getting the circuit ready. However, there are plans to use the cut-down circuit as a means for delaying the deployment of the parachute on descent in the future to further reduce mission distance.
In addition to the cut-down prototype, we were ready to try for a higher altitude in order to capture more spectacular pictures. The Kaymont 600 balloon has a published burst altitude of 75,000-90,000 feet. The plan was to fill it with an entire 125 cu ft. tank again, which is an overfill condition and would result in a pre-mature burst altitude somewhere below the published burst altitude, but would allow us a shorter driving distance for recovery.
The last major detail was planning the location. Priority 1: it should be warmer than the first two launches. Priority 2: again, let's do a warm launch! The team decided to take a flight to Durham, NC to visit a family member currently attending Duke University there and launch in North Carolina (warm!).
Pre-Flight
The launch date was selected for the March 13 weekend and plane tickets were booked. A Test Readiness Review (TRR) meeting was held again 1 week prior to ensure that nothing was overlooked and that the pre-flights were completed and go/no-go launch criteria established.
Mission Objectives
Primary Objectives (Mission Critical):
- Verify Telemetry (TM) system utility, including collection of lost frames
- Verify Payload Cutdown System
- Verify validity and assumptions of flight simulation using TM and Flight Data Recorder (FDR) data
- Finalize TRR, Preflight, and Launch Procedures
- Optional Objective: Record photos during ascent and descent
EFT-2 Flight Hardware
The hardware configuration for EFT-3 was exactly the same as with EFT-2, with the exception of using a smaller parachute for a faster descent, and a Kaymont 600 balloon instead of a 350 for additional altitude before burst. The cell phone was a different model, but served an identical purpose by running the latest TM software for EFT-3.
Risks
In addition to much more rigorous flight planning, the highest risks for EFT-2 were determined as outlined in the chart below. The cut-down device had been originally planned to retire the "tree landing" risk, but had to be abandoned last minute due to lack of testing.
Telemetry
The Telemetry (TM) software was updated for EFT-3 to allow for a few improvements and to test some theories for future flights.
Mainly, the TM software was updated to be able to receive commands once back on the ground, to allow for changes in the message length, the frequency of which messages are sent, and a few other parameters. The software also accepts the “sever” command for the cut-down mechanism, which may prove to have use in future flights as a cut-down or parachute delay mechanism.
Launch Day
Parameter | Imperial | S.I. |
Final Payload Weight | 1.8 lbs. | 0.8 kg |
Measured Nozzle Lift | 6.2 lbs. | 2.8 kg |
Free lift (Nozzle lift – payload weight) | 4.5 lbs. | 2.0 kg |
Estimated Burst Altitude | 79,000 ft. | 24,000 m |
Launch Log:
0 minutes – with a small speech and the dual-salute, EFT-3 is sent off. She disappears into light mist falling from the thick clouds. We flew down to NC for this; we weren't about to scrap our launch just because of a little rain!
1 minutes – Communications have already ceased. Although not unexpected this flight, we had hoped to maintain communications a little longer before losing contact. A plot of temp vs. time shows that the temperature is much more reasonable with 2 hand-warmers. And now we wait.
75 minutes – modeled landing time. Still no messages have been received.
90 minutes – CONTACT. EFT-3 is on the ground in the middle of no-where. She appears to be right on the fringe of what appears to be a grove where very tall trees meet some very short bushes. We route towards the landing zone and wishfully hope that it is in the small bushes…
100 minutes – our team parks at a Methodist Church just outside the tree farm. After reading the posted signs that just forbid firearms and hunting on the land without a permit, we proceed to walk the mile or so towards EFT-3. SMS messages are still coming in loud and clear.
As we proceed along the banks of a small stream, we near the location where the EFT-3 TM beacon has been emitting from. Tall trees on our right, but small trees to our left….still praying that EFT-3 landed a little to the left.
120 minutes – we see her, and she’s on the ground! After de-tangling the lines from thorn bushes, we start the trek back out.
Conclusions:
EFT-3 marks the first successful recovery of a launch, including access to both the FDR data and camera pictures. Although it appears that the balloon may have burst earlier than anticipated (even for the overfill condition), the descent ended up going much longer than expected, so we lucked out in not having it go as high as it could have.
The pictures up at the high altitudes indicated that the payload was experiencing severe sway, potentially flipping end over end at times. It is also worth noting that the balloon to parachute attachment line had wound itself around the parachute
suspension lines about half way up, which
effectively reduces the line length and hence reduces the drag coefficient of the parachute. For future launches, a longer balloon to parachute attachment line should help increase stability, and hence make it more stable on ascent. Furthermore, a parachute deployment mechanism (potentially utilizing the cut-down device hardware) that waits until a prescribed altitude before deploying the parachute would decrease the changes of any lines tangling and reduces the distance and time that would be required for recovery.
Comparison of the actual GPS (red) with pre-flight predictions (yellow) show good correlation with winds, taking into account earlier than expected burst of actual system.
For those interested, the plot of temperature vs. altitude shows that our hand-warmers and cooler insulation design maintained the cell phone temperature within a desirable range for the duration of the flight.