Outcome

Speculative Proposal / Conceptual Design: 

Describe your vision. What is the driving idea behind it? What are your goals and motivations?

  We want to design a garden that directly addresses the basic needs of a plant to ensure its growth: proper watering, proper air quality, and proper sunlight. In response to these three needs, we have implemented three simple systems. The water pumps control the dispensing and collection of water, the carbon dioxide sensors open and close the solenoid, and the light sensor on top of the habitat reads the existing sunlight levels to operate the other systems. We believe that focusing on the basic needs of the plant makes the overall mission easier in terms of complexity and technicalities. We envision this system to work autonomously and separate from human interaction. There will be opportunities for human intervention, but our goal is create a series of systems that respond to Mars’ natural environment or to the climate within the structural shell.  

Prototype:

 Describe your working prototype: What did you create, how, etc.? What tools and technologies were involved? Include appropriate content and illustration

  We designed a habitat that regulates the plants growth through three systems. As mentioned before, each system deals with one of the plant’s basic needs. To water the plants, we pumped water into the habitat from a separate water holding tank, and the pump head releases the water in the form of mist into the habitat. The misting pump runs on a timer, and every five minutes, the pump will mist and humidify the enclosed habitat. To regulate the humidity and air quality, we have used a carbon dioxide sensor that opens and closes an aperture located on the lid. The systems are controlled by a Photon controller, which operates the three systems and sends back data regarding the performance of the three systems. The basic idea is to set up and to arrange different kinds of sensors that control different kinds of functions.    

Precedents: 

Describe the prior work, ideas and projects that influenced your design. What work informed this idea. What other technologies, tools or investigations did you draw on.

  For our precedent studies, we researched aeroponic systems and analyzed their costs and benefits. An aeroponic system removes the need for a growing medium, and having a low pressure system instead of a high pressure system simplifies the project in terms of required systems. While the existing systems that are successful here on earth may not be completely fit for a Martian habitat, they still provide a good indication of what plants need, and how people have used different techniques use the surrounding habitat for their advantage. The precedents and projects that we looked at mainly inspired the whole idea of using a low-pressure aeroponic system; the specific systems we chose and their designs were based on intuition and self-analysis.    

Process: 

Describe how you arrived out the outcome. What iterations, refinements, design decisions and changes were made? Who did what?

Katelyn designed the holding structure for the plant within the jar, which involved taking the jar’s measurements and using the laser cutter to produce adequately sized pieces. The structure takes on a scaffolding approach to hold the plant specimen in place in the middle of the jar.

Marc programmed the systems to operate at their correct times and under their correct circumstances. The water pump operates on a schedule, misting the plant for a minute and then waiting another five minutes to repeat the cycle. The carbon dioxide sensor reads the carbon dioxide levels within the habitat, and it responsively opens and closes the solenoid located at the top of the jar accordingly.

Matthew designed the solenoid plug mechanism that responds to the carbon dioxide sensor’s readings. There was an issue in trying to make sure that when the solenoid received the command to close the system, the seal was completely tight. The neoprene and rubber seal kept falling off due to a weak connection. We ended up threading a wire through the solenoid and the rubber seal, creating a tight connection that was able to seal the habitat completely.    

Reflection: 

What did you learn? What would you do differently?

We struggled mainly with assembly, as it was difficult to set the designed structure and arrange the systems within the limited space. To prevent the structure from moving around or falling over, we designed the structure to have circular plates whose total diameters matched the diameter of the jar. However, because the diameter of the jar’s opening is smaller than the diameter of the whole jar, we struggled fit all the pieces within the volume. We would redesign plant-holding structure to fit the proposed volume in a simpler manner.

We learned that even though we only implemented three systems, things can become complicated quickly. Our previous prototype of having rotating panels to regulate the intake of sunlight became very messy, as evidenced by the sprawl of wires connecting the prototype to the Raspberry pi controller. This shows the need to have individual systems working for a large collective of plants. We cannot have individual jars that each have their own working system. When we build this project on a larger scale, there needs to be one water system, one humidity system, and one light-sensing system for the entire habitat.  

Open Questions and Challenges: 

What questions remain to be addressed? What are the challenges we’ll face when we build the structure at scale?

Based on the response above, one of our concerns is the variety of plant life that we are deciding to have within the habitat. If we are to keep things simple, we ask that only one type plant be chosen, as that leads to a higher accuracy and precision of the levels and thresholds we need to set for each system. However, if we decide to grow a variety of plants to build a case for the versatility of this habitat, we would need to create different sets of levels and data to cater to each plant type.

The struggle of assembly will be alleviated when the habitat is built at full scale, as most of the problems relating to assembly dealt with the shape of the jar itself. However, the overall shape can influence the effectiveness of the systems we set in place. For example, could the shape of the habitat increase the effectiveness of the water collection system? Could the shape of the habitat affect the location of the solenoid plug, changing the process of refreshing of the air within the habitat?