With the emergence of space travel as a form of business, value driven spacecraft design is starting to become an emerging trend. The old way of delivering payload was to get the most there in one trip. The problem with this is that the heavier a payload is, the more expensive it is to deliver it to its target. Lighter and more efficient payload deliveries are a way to increase the overall value of a spacecraft, which is the main focus of the space exploration industry. An American Astronautical Society organized competition called CanSat challenges university students to design, build, and enter a probe into a competition based on certain requirements. The competition Nevada CanSat will build a probe for will focus on aero braking and successful payload delivery. This probe will be launched by a rocket, eject, deploy a heat shield and slow down to 50 meters/sec, slow down again to 5 meters/sec at 300 meters above the ground, and land all while maintaining orientation, recording various types of data, and carrying an egg that must survive the entire mission. The probe must also be 500 grams and fit within a 310 mm length x 125 mm diameter cylinder envelope.
The Nevada CanSat project is part of the space exploration industry. The main focus of the project is to create smaller, lighter probes to get into space for less money than before. In the past the idea was to get as much into space as possible per flight, but recently engineering has changed to support the idea of getting as much technology into space as possible with the least amount of weight. The main producer of space probes is NASA, but more and more private companies are starting to compete to get space probes in the sky. The Nevada CanSat project does not compete directly with any of these companies, but we work with probes for a better understanding of weight reduction, and different engineering principles to better understand the process.
Our team has focused on designs that reduce the weight of our probe. It will be competitive in the cansat probe competition. Our main competitors are other universities looking to make a superior CanSat probe to ours
Proof of Concept
The Nevada Cansat team is endeavoring to develop a space probe that will be able to control its descent and have the ability to land safely and protect a fragile payload. To accomplish these tasks the team developed the following design. There are two drawings, one with the assembled probe, and one with an exploded view.
For the protection of the payload, a hen’s egg, there is a two part harness (3) (4)* that will rest on four springs that all slide along the main frame (2). The probe has to have the ability to relay information to “mission control”, so the probe will be outfitted with multiple sensors, a battery, and a motor. All of these will be affixed to the lower frame (1), underneath the payload. It is outlined in the competition that the probe must be able to shed its heat shield (6) during the flight. So, our design has a dual shell that will be able to break apart when the probe has reached the desired altitude. During landing, the probe must be stay upright, and have a solid foundation. To solve this problem, four spring loaded legs (5) are attached to the outside of the frame and will be released when the heat shield is lost.
Team 10 has done calculations of the CanSat Probe for a proof of concept. The calculations are an important step in showing the probe will work and can be applied to future research and testing for the Nevada CanSat. Hand calculations were carried out to find sizing of parachutes, and strength of springs.
Cost for space travel is based mainly on the weight and size of equipment to be delivered past Earth’s atmosphere. Nevada CanSat’s main goal is to help bring the cost of payload delivery and space flight down by designing a small lightweight probe. The probe itself will have to endure the forces experienced through re-entry and will have to be small enough to fit inside of a small rocket. The probe will also have to protect a payload during launch and re-entry. The product design specifications were developed with the idea of keeping the probe small and lightweight, and at the same time having some of the capabilities that are associated with larger, more expensive probes.
For physical attributes of the probe, it must have the ability fit inside a 125 mm diameter x 310 mm tall cylinder, its total mass must be 500 grams ± 10 grams, and it shall have a 50 mm diameter x 70 mm length compartment to hold payload. Although there are more tedious restrictions including lack of sharp edges and no openings in the heat shield, the previous stipulations have mainly influenced the probe’s design.
Functionality of the probe is far more complex with a great number of requirements. Directly following deployment from the rocket airframe, the probe must be traveling approximately 50 m/s with the heat shield deployed. At 300 m altitude, the heat shield will deploy and a parachute will be released to slow the probe down to approximately 5 m/s. During its entire descent, the probe must not tumble and needs to maintain a constant downward orientation. All structures, including descent control devices and attachment components, shall survive 30 Gs of shock and 15 Gs of launch acceleration.
During descent, the probe shall collect air pressure, outside air temperature, GPS position and battery voltage once per second and time tag the data with mission time. This telemetry needs to be relayed to the team and plotted continuously or in bursts, using XBEE radios. These electronics must be powered by alkaline, Ni-Cad, Ni-MH or Lithium batteries and must be properly protected from the outside environment.
All of these specifications are very important for a successful launch and reentry. A budget of $1,000 keeps the cost to the user low, and can provide a cheaper payload delivery option than what is currently on the market today. Our goal is to provide an economically efficient probe that, down the road, can be marketed and utilized by not only large scale corporations, but the common consumer. At this time, consumers are mainly large-scale investors interested in collecting data in space, and this probe, with further development, could offer an innovative way to do just that.
The fabrication for Nevada CanSat’s probe is a very simple process. Light weight aluminum sheets were measured and cut to the required dimensions with a rotary grinder. In order to save weight, all of the parts of the probe are fabricated from aluminum.All aluminum sheets were bent into their required shapes and were riveted together. The rivets provide a lightweight and high strength method of securing the sheets together.
Testing and Results
Testing for the Nevada CanSat probe needed to be thorough and was broken up into two parts: proof of concept testing and prototype testing. Both parts were equally important in deciding function parameters and the final probe design.
Proof of concept testing included four separate tests to determine the accuracy of initial calculations and thought processes. First, the temperature sensor included with the Arduino was tested to evaluate accuracy and ability to use Arduino programming. Using open source temperature-reading codes found online, Arduino software, an Arduino board, and the included temperature sensor were used to gather and relay the room temperature in graphical form. Testing was extremely successful as the code worked without fault. However, the presented graph was very noisy and sporadic which was largely due to the quality of the sensor itself. Next, a small, 10 g servo motor was tested to determine its ability to pull a large mass to simulate its required pulling force during probe descent. To do this, the servo was placed on a flat table and attached to the servo arm was a 500 g mass, or the maximum weight the servo would be expected to pull. The servo arm was faced towards the ground, with the weight attached, and voltage was applied to allow the arm to rotate 180°. This test was also highly successful. After ten runs of servo testing, the motor was able to quickly rotate the arm with the attached mass with no stalls or stutters. The last two tests, efficacy of the purchased parachute to slow the probe and the egg carriers ability to protect the egg, were conducted at the same time. A small pseudo-probe made of PVC piping was fitted with memory foam and the parachute, which had its expected necessary diameters calculated previously. A small hen’s egg was inserted into the PVC piping with the memory foam and five different drop tests were conducted from a height of 50 ft. while recording time from parachute deployment to touch down. The pseudo probe was then attached with additional weights to bring it up to 500 g before it was dropped from the specified height and results were recorded. Results from these tests were, once again, very promising. Average fall velocity of the 500 g pseudo probe with the parachute was found to be 3.26 m/s which is well below the required 5 m/s. Also, the egg containment device protected the egg during every touchdown with no visible cracks or breaks.
The second part of the testing process, during the prototype phase, was much more “guess-and-check” oriented. After reviewing previous sketches and SolidWorks builds of the expected prototype design, actual fabrication was found to be much more difficult than expected. The first test assess the ability for the servo-motor to pull the pin used to release the heat shield, as opposed to a simple 500 g mass. Upon testing, the motor was unable to generate enough force to pull the pin due to much higher frictional forces than was expected. To fix this, the entire heat shield was redesigned to form a more efficient and simpler way to deploy the shield. As can be seen in the deployment video, the new design uses the force of the initial drag parachute to pull against a servo-motor inside of the probe. When the probe is activated by the Arduino, the servo rotates allowing the the drag shoot to pull off the head shield lid which then leads to the full heat shield falling off. Testing with this new method has proven to be extremely effective and in over 30 tests, it has not failed once. A simulation of this new release apparatus in action can be seen in the supplied video. The final testing required was incorporation of all other required sensors for the probe, allowing them to all collect and relay data simultaneously. During coding, the largest obstacle was the inability to have all different data sets, five in total, to graph their data independently of one another. Original graphs with less intricate coding attempted to graph all five different data sets on the same line which lead to graphs with extremely high frequency oscillations going from 0 to 10,000 on the y-axis. The team then consulted with other computer science students who were helpful in forming a code that could successfully collect and graphically relay all necessary data. This final test concluded all necessary testing for the Nevada CanSat probe.
The Nevada CanSat probe solves the problem of heavy, expensive space travel. Although this current probe is only launching 600 m into the troposphere, the basis for its design and fabrication will be carried on to probes that will reach space. Currently, the Nevada CanSat probe is the only of its kind that is over 150 g lighter than its weight requirement while using only one third of its $1,000 budget for construction. Although the main goal of this project is to build the most lightweight, cost effective probe possible, we also hope that this opens a new door for others looking to invest in this field as Nevada CanSat offers an innovative and unthreatening version of space exploration. Although we have not been able to market this product officially, users at the Nevada Innovation Day were thoroughly impressed and interested in the product itself.
Meet the Team
The most challenging engineering project Damond Goodwin has been a part of was at his internship at Integrated Systems Incorporated in South Carolina. The project design involved using robots to palletize hospital bed trays. The job was difficult because of the programming and wiring involved to complete the project. Goodwin did not have much experience in electrical work or programming, but was able to quickly learn on the job to get the autonomous systems working, with the help of his coworkers. One of the engineering skills Goodwin has improved upon over his college career include his ability to quickly assess and solve problems on the job site. He has also improved his CAD and SolidWorks skills over the years to a proficient level.
Outside of school Goodwin has designed and built the largest hammock in Reno NV. The dimensions of the netting for the hammock are 10’ by 25’. The loads and forces created on the hammock are very large and were considered in the design process. The hammock is capable of holding up to 15 people weighing 160lbs with a factor of safety of 3. The hammock is an example of something he is proud of building outside of school and work. The design process allowed him to assess a problem and use analytical techniques for designing accordingly to solve the problem of considerable weight in the hammock.
Damond Goodwin is From Cedarville, California. His main goal for right now is to finish college and pay off his student loans. He is working almost full time while going to school to accomplish this. After he graduates he plans on getting an engineering job to save up money to buy a Bluewater capable sailboat. He then intends to modify the sailboat for a trip around the world via the five capes. The boat will need considerable reinforcements to the mast and rigging to be considered safe for the Southern Ocean, where knockdowns are not unlikely. After the boat is fully modified and safe he plans on completing a circumnavigation via the five southern capes.
Brandon Alber, born and raised in Las Vegas, Nevada is a senior in the Mechanical Engineering program at the University of Nevada, Reno. Brandon has held many positions throughout his college career, working construction and engineering internships where he has learned the values of a strong work ethic and attention to detail. His most challenging engineering experience came with his internship at Integrated Systems Inc. in South Carolina. ISI is a company that integrates automation into company’s production process. Brandon drew from his previous engineering coursework to complete tasks such as wiring, assembly, design and building of parts utilizing SolidWorks and various machines to meet customer needs. This internship tested Brandon’s knowledge and abilities he had acquired from school and expanded his skills with a hands on approach. Brandon plans to seek engineering employment following his graduation in the Fall of 2018.
Andrew Bradford is from Las Vegas, NV and is currently in his fifth year at UNR. Andrew will be graduating in the spring of 2017 with a bachelor’s degree in mechanical engineering with a minor in business administration. Outside of school, Andrew enjoys skiing, going to the lake, and doing just about anything outside. Andrew has been employed at Gardner Engineering, Inc., a local HVAC and plumbing contractor, for over two years as an estimation and project management intern. After graduation, Andrew plans on working in the field of project management.
As a presidential scholar, Gunner Scott has always taken his education seriously and has proven this by being on the Dean’s list every semester of his undergraduate career. Gunner has be a member of multiple research teams, and found his greatest challenge while working at the University of Shanghai, where he was tasked with modeling and developing a Magnetic Deformable Mirror for image resolution aberration correction for optometry and astrology applications. Through multiple testing and developing a gridded double layer system, with varying copper coil sizes, was established. The double layer system allowed for both large and small stroke capabilities, which allows for a greater range of aberration correction.
Gunner Scott is a larger member in Concrete Canoe and is the paddling team’s main steersman for men’s sprint and endurance. During competition Gunner and his teammates won every race gaining a large portion of points for the overall team.
Gunner Scott was born on the East Bay of California and spent a large part of his youth in the area, until moving to Truckee California, and finally Sparks Nevada. During the remainder of his undergraduate career Gunner’s goal is to graduate with a high enough GPA and enough extracurricular activities to apply and move onto graduate school in Engineering Education, eventually striving for a Ph.D.
Davison Beenfeldt is a current senior from Reno, Nevada in the mechanical engineering program at the University of Nevada. Through his college career, Davison has strived for academic and personal excellence through his extracurricular activities and classes. As an engineering student, he has acquired a position on the Dean’s List for the College of Engineering for the past 3 semesters. Davison has used his knowledge of engineering in many aspects of his life, including design of a Homecoming float which required tedious and thorough calculation to successfully build. Next to taking classes, Davison has also held positions in his fraternity, Sigma Phi Epsilon, the Interfraternity Council, and the Associated Students of the University of Nevada throughout his college years.
Davison’s goal for after undergrad is to attend medical school at the University of Nevada or at another nearby school. He hopes to then gain residency in orthopedic surgery so he is able to apply his mechanical engineering degree to the medical field.