Decatur Mars Atmosphere Team Experiment Explanation
The Need:
We were given the task of designing and prototyping an experiment that could be
performed on Mars on the Mars Sample Return Mission. Through our research we were unable
to find accurate data about the Martian atmosphere at various altitudes. We wanted to design an
experiment that would be able to take measurements at various altitudes on Mars.
Science Objective:
Our science objective was to record and collect atmospheric data at various levels of the
Martian Atmosphere. This data would consist of atmospheric temperature, pressure, wind speed,
radiation, magnetic force, humidity, and density. We also have a secondary objective of taking a
photo of the Mars Sample Return Lander as we are measuring the atmospheric conditions.
Constraints:
We were given certain parameters that our experiment had to follow. The experiment had
to fit into an 18 inch cube. The experiment had to weigh less than 10 kilograms. The experiment
was allocated a continuous supply of 50 watts of energy from the Lander. The experiment had to
contain its own data storage and transmission device. The experiment had to be completed
during the duration of the mission.
Solution:
Our solution to accomplish the science objective is called the Martian Balloon. The
Martian balloon consists of a 9 meter diameter balloon made out of a five mil thick Mylar,
Kevlar, and Polyethylene combination. The balloon is attached to a small payload via a series of
cables. All of the measuring devices, battery, and transmission devices are located on the
payload.
Experiment Concept of Operations:
The initial Concept of Operation is to gather energy for our experiment. We are allotted
50 watts of energy, and that energy will be used to slowly charge battery’s onboard the balloon
payload. The next Con-Op is to inflate the balloon. The entire balloon starts folded up, and once
enough energy is required for the experiment, the balloon starts to inflate. The balloon will be
attached to a helium line that, through regulator valves and switches, will slowly inflate the
balloon. Once properly inflated the next Con-Op will be carried out, deploying the balloon. The
helium line will act as a tether, keeping balloon attached to the Lander. The pressure inside the
balloon will be monitored, and when the right pressure is reached, the helium line will break off,
allowing the balloon to rise. The next Con-Op is data measurement and transmission. While
climbing the atmosphere, data will be constantly recorded and periodically sent back to the
Lander. The balloon will continue to record and transmit data back to the Lander until the
batteries run dry, or the balloon is unable to sustain itself.
Balloon Technical Details:
The folded up balloon is calculated to take up roughly 2000 square inches, or 34 % of the
allotted volume. The balloon will consist of layers of Mylar, Kevlar, and Polyethylene, and
adhesive to hold the layers together. Mylar can be made with a thickness of 1.5 mils, Kevlar can
be made with a thickness of .24 mils, and Polyethylene can be made with a thickness of .24 mils.
The team projects the entire balloon to have a thickness of 5mils. With data obtained from
another source the balloon material is assumed to weigh around 6 Kg, while it would displace
7.63 Kg of Martian atmosphere. When properly inflated the 9m diameter balloon has a volume
of 381.7m3. With this difference, the payload and instruments is allotted 1.25 Kg of mass. There
is a small opening on the bottom of the balloon where a helium line would be attached to.
Payload Technical Details
The payload consists of a very thin sheet of titanium that is 12” by 12”. Titanium was
chosen because it is very strong, and lightweight. All of the instruments are mounted on the sheet
of titanium in a way that they do not interfere with each other. We have found commercially
available instruments that would take the required data measurements, however, if this project
was going to be performed on Mars, custom made instruments would be recommended. We are
using several sensors that were on the Beagle 2 Mars Lander. For pressure, we want to use the
Beagle 2 capacitance manometer. We want to use the instrument that was used to measure
temperature on the Beagle 2 Lander as well. We also want to use the Radiation sensor that was
used on the Beagle 2 mission. To measure our position and velocity, we plan on using a three
axis accelerometer. We want to measure humidity with a hygrometer, wind speed with a hot film
anemometer, and use a magnetic field sensor to measure magnetic field.
Project Team:
The team is comprised of 10 members from Decatur High School. There is one senior, 8
juniors, and one sophomore on the team. The Project Manager is Dhruv Patel. The systems
Engineer is Max Beasley. The rest of the team members are: Trey Hargett, Jonathan Ford, Brent
Higdon, Austin Lambert, Jay Chenault, David Martin, Hayden Naumann, and Trey Keown.