Matt Breihan, Jay Davis, Jack Gregory, Ashton Schrage, Sara Schuette, and Lydia Whitney October 14, 2008

Mission Statement The BalloonSat Octagon shall ascend to approximately 30 kilometers while recording the intensity of light as a function of altitude through three photometers with three different light filters. This will determine which wavelength of light should be used to photograph objects when a satellite is at different altitudes. Octagon will also carry a digital camera to photograph the ascent/descent and internal and external temperature and humidity measuring devices to record conditions inside and outside of the BalloonSat. Planned Discoveries We plan to discover the atmosphere’s affect on light penetration. How far different wavelengths of light penetrate the atmosphere can be measured by the relative intensity of the wavelengths of light as a function of altitude and shall give us data that we can use to determine what altitudes are best for observing objects in the universe if using a specific wavelength of light.

Mission Overview Hypothesis Our hypothesis is that as the BalloonSat’s altitude increases, the light intensity will increase because there will be less atmosphere so not as much light is absorbed. We also think that the light intensity of the extremes on the spectrum (violet and red) will increase slightly more than the middle because the lack of atmosphere will result in more ultraviolet and infrared wavelengths as altitude increases. Why we are doing this mission We are proposing to build this satellite because we are interested in astronomy and want to determine the effect the atmosphere has on the amount of light observed by telescopes at different altitudes. The atmosphere absorbs light from objects in space and this prevents astronomers from getting pictures of objects at different wavelengths of light without getting above the atmosphere. Different wavelengths are absorbed at different altitudes so if we can find the lowest altitude that a certain wavelength of light reaches, astronomers will only have to send a telescope up to that altitude to observe objects, which costs less than sending a telescope or camera to an altitude completely above the atmosphere.

 Top Level 0 -1) Construct a BalloonSat to launch on a high altitude balloon that will ascend to approximately 30 kilometers while keeping the cost under $150 and the weight under 1 kilogram by November 15,  Lower Level 1 - 1) The BalloonSat Octagon shall not exceed $150 in cost, 1 kilogram in weight, and shall be completed and ready to launch by November 15,  Top Level 0 - 2) Measure the intensity of light through three photometers with different wavelength filters as the BalloonSat ascends and record the data on a Basic Stamp.  Lower Level 1 – 2) The BalloonSat Octagon shall measure the light intensity through three photometers each with a different light filter (red, blue, and green). The photometers shall be positioned at a 45 degree angle as to not record light reflected of the balloon or from the horizon. The photometers shall take measurements at a set interval throughout the flight and the data shall be recorded on a Basic Stamp.  Top Level 0 – 3) Measure the internal and external temperatures of the BalloonSat during the ascent and record the data on a HOBO data logger.  Lower Level 1 – 3) The BalloonSat Octagon shall include internal and external temperature sensors and shall be programmed to measure the internal and external temperatures at a set interval throughout the flight. The measurements shall be recorded on a HOBO data logger. The internal temperature shall be kept above 0 degrees Celsius through use of a heater. The external temperature sensor shall be placed as far from the BalloonSat as possible in order to get an accurate reading.

 Top Level 0 – 4) Measure the internal humidity of the BalloonSat during the ascent and record data on a HOBO data logger.  Lower Level 1 – 4) The BalloonSat Octagon shall include a humidity sensor that will be programmed to measure the internal temperature at a set interval throughout the flight. The data shall be recorded on a HOBO data logger.  Top Level 0 – 5) Capture pictures of the environment around the satellite using a Canon digital camera and recording the images on an internal memory card.  Lower Level 1 – 5) The BalloonSat Octagon shall include a Canon digital camera with an internal memory card and shall be programmed to take pictures at set intervals throughout the flight. Proposal Requirements The requirements state that our BalloonSat shall include a digital camera, HOBO data logger, external temperature probe, and an additional science experiment. Our design complies with these requirements with our additional experiment including the use of three photometers with different light filters to determine the atmosphere’s effect on light penetration. The requirements also state that the flight string interface tube shall be a non-metal tube through the center of the satellite and that the BalloonSat’s weight shall not exceed 1000 grams, requirements our current design comply with.

 How we are going to complete our mission ◦ Using three photometers with different light filters, we will record the intensity of light at set intervals and store the data on a Basic Stamp. The three filters will measure three different wavelengths of light and will be positioned at a 45 degree angle to avoid pointing at the horizon and the sun. When we recover the satellite, we will retrieve the data from the Basic Stamp and graph the data from each photometer using altitude and light intensity. Then we will determine how far different wavelengths of light penetrate into the atmosphere and what wavelengths of light can be observed at any given altitude.

Other aspects of mission Measuring and recording external temperature, internal temperature, and humidity. This will be completed by measuring and recording measurements with a HOBO data logger. Recording the ascent/descent with photography. This will be accomplished by programming the Canon camera to take pictures every 20 sec. Parts Ordered or Provided: Camera with batteries and 1 GB memory card, heater with batteries and switch, HOBO data logger/external temperature cable, foam core, batteries,3 TSL230 plus spares (from Future Electronics), and Basic Stamp (from Mouser Electronics) Parts still need to be ordered: Development board for Basic Stamp (Mouser Electronics) and light filters.

Drawings Front three panels folded back with internal components

Drawings Front and back views with external components

Drawings Detail of photometer cut-out

Budgets Weight Money All other weights (foam core, insulation, aluminum tape, wires, battery holders, etc.) shall not exceed 363 grams.

To check the how well the satellite absorbs shock; the team shall perform a drop test by dropping the structural housing for the satellite at least thirty feet. To see how well the satellite can withstand extreme cold temperature, the team shall perform a cooler test, in which they shall place the satellite in a cooler with dry ice for an extended period of time. To make sure the satellite will hold together when the balloon bursts, the team shall perform a whip test by attaching string to the satellite and swinging it around. Subsystem tests shall be carried out to ensure that each function of the satellite works properly, including a tests of the heater, camera, HOBO, photometers, external temperature cable and Basic Stamp. Each subsystem test shall include attaching the components to a power source and running basic functions. Functional tests shall be employed to ascertain that each task that the satellite runs smoothly. These tests shall make certain that the camera takes pictures on the correct time intervals, the heater keeps the satellite warm enough, the HOBO functions and the photometers are calibrated. The calibration test shall be carried out by shining different wavelengths on the photometers inside the box to make sure they pick up the right wavelength, and also that they are aligned and focused. Mission sim tests shall be carried out to test that every procedure is executed out at the correct time for the entire flight.

Tests already performed: Drop and Stair Test Oct. 13, we kicked a prototype BalloonSat with rocks as simulated masses drop the steps inside the DLC several times at different angles. Afterward we dropped the BalloonSat off of the top floor of the parking garage twice. The damage done to the outside from the stair test was minimal, corners flattened slightly and small indentation on the top side. The BalloonSat landed directly on a corner when we dropped it the first time, resulting in two of the seams splitting open. We have not opened the BalloonSat to see the damage done on the interior. Test Schedule

Expected Results A general increase in light intensity at all wavelengths as altitude increases. Slightly larger increases in light intensity at the extremes of the visible light spectrum ( violet and red). External temperature drops to well below zero degrees Celsius. With the use of a heater, we expect to be able to keep the internal temperature of the BalloonSat above zero degrees Celsius. Digital photographs taken at approximately twenty second intervals that record the ascent and descent.

Time Programming the Basic Stamp/photometers Getting all the electrical components connected Weight limit