Aether I - 3/14/2014

Bryant's first encroachment on space - Aether I.

A brief introduction to the 2014 Aether project

Sample video from the Aether I

The Challenge - Aether I was the first stab at space made by Bryant Hornet Engineering's Aeronautics and Space division. Students from our Aerospace Engineering class headed the charge with additional support from H.E.A.T. members. Mr. Williams, Aerospace Engineering instructor and project supervisor, had conducted a similar experiment in the past, bringing some experience to the project. This capsule, however, was destined to be much more advanced than Williams' previous effort.

Initial capsule construction

Design - Aether I 's shape was decided upon early in class discussions after it was determined that re-purposing a commercially available cooler was not ideal for this application. The pyramid shape offers reasonable interior volume and very low/centered center of gravity, offering great stability upon (sometimes rough) landings; better ensuring that the capsule would remain upright upon rough landings. All loaded weight/equipment was positioned as low and centered as possible. Students designed the capsule's shape and dimensions in Autodesk Inventor before construction.

Further capsule construction

Construction - The bulk of the Aether I capsule materials can be found at Lowe's. As you can see here, the capsule was constructed of rigid insulation. It was critical to insulate the interior of the capsule to ensure that batteries continued operate at max altitude where atmospheric temperatures can drop below -40 degrees. Great Stuff sealed seams nicely. In these photos, you can see a final wrap of reflective, semi-flexible insulating material that adds to the overall R-factor while looking great and "spacey."

Beware: Wrapping with a foiled material such as this one, while being an excellent and lightweight insulator, can cause a significant Faraday Effect - blocking radio signals from entering or escaping your little Faraday Cage. Due to the last-minute completion of the Aether I capsule, we had little opportunity to test all equipment with the door of the capsule closed. Lesson learned.

A peek inside the completed Aether I capsule

On-board Equipment - Aether I carried significant tech along its journey.
- A GoPro equipped with battery bacpac recorded 1080p bird's eye video through the bottom of the capsule.
- A Canon Elph point-and-shoot camera captured stills out the side of the capsule thanks to a CHDK hack that allowed the small camera to run a script, firing the shutter every 60 seconds.
- An APRS unit equipped with a specialty GPS chip (unlocked to work above the federally regulated 60,000' ceiling typically imposed on civilian GPS) allows for telemetry to be radioed over amateur bands and bounce off digi-peaters until an internet gateway is found. The location of the unit can then be tracked in real-time over the internet.
- A flight computer, again equipped with a similar GPS chip, served as a redundant telemetry recording device and recorded additional data such as outside temperature, atmospheric pressure, and humidity. An attached probe protruded from the capsule to monitor conditions outside the capsule.
- This equipment was powered by eight Energizer Ultimate Lithium AA batteries. Lithium batteries, while much more expensive, are significantly lighter and operate at much lower temperatures than their alkaline counterparts; making them ideal for this application.
- A voltage regulator (you can see the attached heat-sink) was utilized to allow our 12V APRS unit and 5-7V flight computer to use the same eight batteries rather than hauling additional batteries along.
- A pair of credit-card-sized temperature loggers were stowed in the capsule to record internal temperature and later evaluate the performance of the capsule's insulation.

Fully equipped, flight-ready weight - 45.9oz.

Where did the name come from?

In Greek mythology, Aether was a personification of the upper sky; embodying the air breathed by the gods. Later, the name became attached to a theorized element that was believed to fill the void of space.

What does Aether do?

The capsule itself houses and protects all of our equipment along the journey. The Aether capsule is designed with insulating properties to keep power sources warm in the sub-zero temperatures of the upper atmosphere. (The chemical reactions that allow batteries to provide voltage slow down in severe temperatures, reducing their efficiency.)

Do you need permission to do this?

We notify our local FAA authorities and follow FAA regulations for free balloons defined in FAR 101.

Will it come down?

As the capsule will not accelerate fast/long enough to escape Earth's gravitational pull, it must at some point come down. The balloon will expand throughout its flight (due to dropping atmospheric pressure). When it can stretch no further, it will pop. The capsule will then accelerate back towards Earth's surface.

How do you find it?

Ideally, our on-board APRS (Automatic Position Reporting System) unit will be sending us coordinates of the capsule's whereabouts every two minutes, and we are simply able to chase the capsule to its landing site. Future Aether models will likely utilize additional systems of other varieties to operate as back-ups.

Why do you launch in late-winter/early-spring?

Prevailing winds typically carry balloons east from Bryant, making our potential landing areas predominately farm land. By this time of year, duck season is over and most fields that are flooded for the season have been drained. Fields are bare (making a reflective capsule and bright-colored parachute easier to spot), and farmers are out and about preparing for planting (bettering the chances of someone spotting it).

How did you know where it may come down?

We use Cambridge University's Spaceflight Landing Predictor (github). The system gathers weather data to predict the flight path of weather balloons, given launch location, time, and ascent/descent velocities.

How high does it go?

The max altitude of a sounding balloon such as those used in the Aether Project can vary, dependent on many variables such as weight of payload, maximum volume of the balloon, volume of the balloon at launch, and weather conditions, to name a few of the more critical ones. Our target with Aether I was 100,000'; however, the decision was made to sacrifice altitude for a quicker ascent speed and a larger volume at ground level was dialed in. The balloon traveled to a max altitude of roughly 80,000' very quickly as a result.

Why is Aether I pyramid shaped?

Initially, the idea for a pyramid shaped capsule was proposed in class discussion, almost in jest. Upon quick consideration, it was clear that a pyramid would have a very low center of gravity and have great stability upon landing, bettering the likelihood of the capsule landing upright (which is critical to the operation of the GPS units inside).

How does it get back down?

Gravity; but seriously, getting down safely is a concern. Once the balloon bursts, the capsule rides back to the ground on a parachute that hangs near the center of the line between Aether and its balloon. The capsule falls very quickly at first until the atmosphere's density becomes sufficient to actually fill the chute and slow Aether to a safe landing velocity.

Where is it now?

Currently, the capsule is residing in Building #22 (The Bryant Engineering Center) being assessed for contributions to its successor, Aether II. When this is complete, electronic components will be removed and Aether I may make a tour of display cases/tables throughout the district before returning to Building #22 for permanent display.

What was inside?

Aether I contained - a GoPro Hero 3, an APRS unit (GPS4 chip/15 watt radio), an Eagle flight computer (recording position, outside temp, humidity, and pressure), a Canon Elph point-and-shoot camera (running a CHDK script to capture stills in 60 second intervals), a pair of data loggers (recording interior temp), eight Energizer Ultimate Lithium batteries, a voltage regulator w/heat sink (to power the 12V APRS and the 5-7V flight computer from the same 12V source), a pair of Hot Hands, three Bryant Hornet Engineering buttons (one given to Channel 7 Daybreak crew, one currently in Mr. Pickering's office, one currently in Mr. Williams' office), and a fun-size Twix bar.

How cold did it get?

Temperatures outside the capsule reached a recorded -43 degrees (C and F are very near the same at this temp). Temperatures inside the Aether I capsule never dropped below 64 degrees Fahrenheit.

How far did it go?

Aether I traveled almost exactly 100 miles across Arkansas.

How fast did it travel?

Traveling 100 miles across Arkansas in only an hour and twenty minutes, Aether I averaged an impressive 75mph. Since windspeed near the surface was obviously nowhere near 75mph, it can be safely assumed that the capsule must have broken 100mph while traveling through the jet stream. Pretty impressive.