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VOIDS - Final Project for AAE 25100: Introduction to Aerospace Design
The search for life on a faraway world.
The search for life on a faraway world.
For the final project in AAE 25100: Introduction to Aerospace Design at Purdue University, student teams of six were tasked with conceiving, designing, and modeling a theoretical mission to Venus in search of potential signs of life. This project required comprehensive planning, including launch, space travel, and arrival, with all mission parameters determined and calculated by the team. Each team member gained hands-on experience in various aspects of rocket mission design. The project culminated in a detailed report and a recorded "hype" video, showcasing our design choices and the rationale behind them. The explanation video is attached at the bottom of this webpage.
Project Background
Project Background
As part of the Aeronautical and Astronautical Engineering (AAE) curriculum at Purdue University, the AAE 25100 course offers students the opportunity to design a fully-sized, calculated, and student-led space mission. Throughout the semester, we were introduced to critical space mission design techniques and theories, including rocket equations, Vis-Viva and orbital maneuver equations, among others. These concepts were directly applied to our mission design project, where we were encouraged to develop original ideas for our theoretical mission.
My team and I conceptualized VOIDS: a swarm of atmospheric probes to be strategically deployed by an orbiter into Venus' atmosphere at designated points of interest. These points would be identified by the orbiter itself, which would be equipped with wide-angle cameras to scan for high-altitude atmospheric anomalies. Upon detecting such an anomaly, the orbiter’s flight computer would adjust its orbit to bring it closer to the region of interest.
The probes were designed to carry atmospheric instruments to measure characteristics that might indicate signs of life within Venus' atmosphere. Due to the extreme conditions, the probes were also designed to self-destruct upon descending through the atmosphere, minimizing the overall mass of the mission. To ensure the transmission of valuable data, the probes were equipped with communication devices to relay all collected information to the orbiter before their eventual destruction. The orbiter, in turn, would transmit the findings to mission control on Earth, providing scientists with valuable data regarding potential signs of life in Venus' atmosphere.
The inspiration behind our mission stemmed from a particular altitude in Venus' atmosphere—approximately 30 miles above the surface—where past missions have found temperatures ranging between 86° and 158° F, which could be conducive to life. The probes were armored to withstand the harsh conditions of Venus’ atmosphere up to this altitude, after which they would begin to degrade due to high pressure, temperature, and acidity. Additionally, recent observations have detected dark streaks in Venus' atmosphere that persist despite strong wind conditions at the planet's highest altitudes. These streaks could represent areas of interest for our mission. The probes would descend through these regions, gathering atmospheric data and immediately transmitting it back to the orbiter for further analysis.
This mission is also driven by the fact that there has been a lack of large-scale missions to Venus in recent decades. Much of what we know about Venus' atmosphere comes from missions conducted decades ago, and advancements in technology now allow us to gather more precise data from extreme environments. Motivated by the goal of obtaining answers to these pressing questions, we set out to design this mission.
My Work
My Work
The initial phase of the space mission design process involved addressing the fundamental questions that would shape the mission: Why choose Venus? Who are the stakeholders, and what are their needs? What will the mission consist of? Venus is the closest planet to Earth and shares similarities in size and composition with our planet. It also shows potential signs of past and possibly present life within its dense atmosphere. This makes Venus an attractive target for scientific exploration, especially for astrobiologists interested in gathering novel data to examine for signs of life. Furthermore, a mission to Venus would be funded through taxpayer money, so it must adhere to a reasonable budget.
Once the foundational questions were answered, we proceeded with the detailed mission design process. We established requirements for each stakeholder involved in the mission. These included ensuring the probes survive to a specific altitude in Venus' atmosphere, housing the necessary instruments for atmospheric readings, and adhering to weight and budget constraints. Additionally, we conducted a comprehensive risk assessment to identify potential threats to the mission's success and devised mitigation strategies for each identified risk. Below are the risks and corresponding mitigation strategies:
Launch Risks:
Launch Risks:
Mission delays due to missing the scheduled Hohmann transfer window, resulting in suboptimal trajectories and travel paths.
Mitigation: Detailed mission scheduling and coordination with launch providers to ensure timely launch within the designated transfer window.
Launch failure, including failure to reach orbit or other technical issues (explosion, fuel leak, launchpad malfunctions).
Mitigation: Comprehensive testing of launch vehicle systems and redundancy protocols to ensure backup systems are in place.
Payload fairing deployment failure, potentially compromising payload deployment.
Mitigation: Thorough pre-launch testing and real-time monitoring of the deployment process.
Transport Risks:
Transport Risks:
Initial stage separation failure, preventing the transport vehicle from reaching heliocentric transfer orbit.
Mitigation: Rigorous testing of stage separation mechanisms and backup deployment systems.
Navigational deviations during interplanetary travel, resulting in trajectory issues.
Mitigation: Continuous trajectory tracking and course correction maneuvers.
Venus orbital insertion failure, preventing successful entry into Venus' parking orbit.
Mitigation: Redundant systems for orbit insertion and precise mission planning.
Technological Risks:
Technological Risks:
Heat shield malfunction during interaction with Earth's or Venus' atmosphere.
Mitigation: Use of advanced heat shield materials and real-time monitoring to adjust for atmospheric conditions.
Probe deployment failure, preventing successful atmospheric observations.
Mitigation: Robust deployment mechanisms and extensive pre-launch tests to ensure probe functionality.
Communication loss between the satellite/probe system and Earth, preventing data transmission.
Mitigation: High-reliability communication systems with backup channels for data transfer.
Solar panel degradation, leading to insufficient power for spacecraft and probe functions.
Mitigation: Use of high-efficiency solar panels and battery backup systems.
Instrument calibration failure, preventing accurate measurements.
Mitigation: Continuous monitoring and recalibration of instruments throughout the mission.
Operational Risks:
Operational Risks:
Budget overruns due to unforeseen difficulties.
Mitigation: Close budget tracking and contingency planning for unexpected costs.
Schedule delays, preventing the timely launch of the mission.
Mitigation: Careful scheduling and allocation of resources to meet mission milestones.
Environmental Risks:
Environmental Risks:
Solar flares and radiation impacting spacecraft instruments, reducing or destroying their functionality.
Mitigation: Radiation shielding and careful mission planning to avoid high-radiation periods.
Temperature variations in space and Venus' atmosphere, affecting spacecraft instruments.
Mitigation: Thermal control systems and temperature-resistant materials for instruments.
Micrometeoroid and space debris impacts damaging spacecraft structures or instruments.
Mitigation: Shielding and impact-resistant materials to minimize damage from space debris.
After conducting the risk analysis, I moved on to developing the mission profile, which would outline the goals and stages of our mission. The mission profile, provided to the left, was crucial in guiding our design process. With the profile in place, we began working on calculating all the parameters relevant to each stage of our mission.
Our first task was to estimate the maximum mass and size of our entire payload, which we determined to be approximately 5000 kg. Based on this estimate, we concluded that the SpaceX Falcon Heavy rocket would be the most suitable choice for inserting our payload into low-Earth orbit (LEO). Knowing that launching from lower latitudes is more efficient for achieving the required ΔV for LEO, we selected Cape Canaveral, Florida, as the launch site.
Using principles taught in class, combined with MATLAB for efficient calculations, we were able to determine the necessary ΔV for each stage of the mission. The ΔV calculations for every stage were integral to understanding the energy requirements for our spacecraft. I have attached two key figures: the stage outline of our mission and the ΔV calculations for each stage.
Through this stage of mission design, I learned how to apply theory from Vis-Viva and other relevant equations to calculate the necessary ΔV for a basic Hohmann Transfer, achieving a parking orbit around a celestial body, performing orbital plane changes, and accounting for orbital losses from external factors. These calculations were fundamental in ensuring the feasibility of our mission.
Mission Stages
ΔV Maneuver Calculated Values
After completing the initial calculations, we proceeded to size our rocket and internal payload. As mentioned earlier, we decided to use the SpaceX Falcon Heavy rocket for the launch into Earth's orbit. Our mission was divided into three rocket stages, each playing a crucial role.
The first stage would launch from Kennedy Space Center (KSC) to Low Earth Orbit (LEO). This would be achieved by the rocket delivering a ΔV of 11.48 km/s. Once the first stage’s role was complete, the empty rocket components would detach. Following this, the second stage would provide 3.172 km/s of ΔV to achieve a heliocentric transfer orbit to Venus. Like the first stage, this stage would also detach after fulfilling its task. Finally, the third stage would deliver a further 3.278 km/s of ΔV to establish an initial orbit around Venus, and an additional 0.143 km/s would fine-tune the orbit to its final long-term trajectory. The third stage would detach from the payload after this final maneuver. All stages would separate via pyrotechnic fasteners once their ΔV contributions were complete.
To choose the appropriate propellants for each stage, we considered the propellant selection principles from class. For the second stage, we opted for an RP-1/LOx combustion reaction due to its high specific impulse (ISP) of 348 seconds. However, for the third stage, which would operate in deep space where cryogenic oxidizers like LOx can boil off due to solar radiation, we selected a hydrazine/pentaborane combustion reaction, offering an ISP of 327 seconds.
Once we had determined the ISP values, we focused on sizing the payload. Using prior art as a guide, we estimated the mass of each internal component. Our solar panels, based on the power input required for the payload's functionality, had to be 0.4 square meters, resulting in a mass of approximately 8 kg. We chose lithium-ion batteries to provide the necessary energy storage, which added 80 kg to the payload. The high-gain antenna, responsible for communication between the payload and Earth, was estimated to weigh around 15 kg. We also added two complementary low-gain antennae, each weighing 2 kg, to facilitate communication between the Venus Orbital Instrument Deployment Systems (VOIDS) and the orbiter. Since the VOIDS would disintegrate as they fell through Venus' atmosphere, they needed to transmit data to the orbiter before doing so, and the orbiter would then communicate this data to Earth.
The flight computer was estimated to weigh about 10 kg. After accounting for these components, the remaining mass was allocated to the VOIDS. Each VOIDS unit would house industrial-grade temperature sensors, high-temperature silicon carbide MEMS gas sensors, Huygens atmospheric structure instruments, and ion-sensitive field-effect transistors (ISFET) pH sensors. These instruments would gather essential data on Venus' atmosphere. By summing the masses of these components, we arrived at a total payload mass of 6437.8 kg.
Using the final payload mass, we applied the rocket mass calculation equations from AAE 25100 to calculate the masses of the rocket's stages. This process was done top-down: using the final mass to determine the initial mass. The mass of stage 3 fuel was calculated to be 37,882.46 kg, bringing the total mass for stage 3 to 40,843.63 kg. Stage 2 fuel mass was calculated to be 13,928.45 kg, with a total stage 2 mass of 15,322.83 kg. The total mass of the rocket, after including all stages, was calculated to be 1,483,392.26 kg.
Next, using the Oxidizer/Fuel (O/F) ratios for each fuel combination along with the calculated propellant masses, we proceeded to determine the required tank sizes. The results of these tank sizing calculations are shown to the left, highlighting the necessary tank sizes for each of the selected propellants and oxidizers. This step was crucial for ensuring that the tanks would be properly sized to hold the required amounts of fuel and oxidizer for each stage of the mission.
CAD Model for Orbiter
CAD Model for an individual VOIDS
We then entered the concept generation phase of our mission design. With the main idea already decided—a swarm of atmospheric probes (VOIDS) that would be deployed through the atmosphere and strategically inserted by an orbiting spacecraft—I began developing a basic CAD model of the orbiter using Siemens NX. The orbiter design featured three antennae, sized based on prior missions like Cassini and BepiColombo, which are included in the model to the left. Alongside this, I also created a CAD model for the VOIDS, which is shown to the right of the orbiter model.
With the size of each VOID already estimated, we proceeded to design their deployment mechanism from the orbiter. Although a full CAD model wasn't created due to the complexity and limited time, I proposed a concept that involved using a stacked revolver system for deployment. The orbiter would be nearly hollow inside, with instrumentation at the top and wide/narrow-angle cameras at the bottom. The revolver system would function like a pistol, where each "slot" in the revolver would hold a stack of VOIDS. Over time, the VOIDS would eject one by one, and once a stack was emptied, the revolver would rotate to the next one. This process would continue until the orbiter was empty, signaling the end of the mission. The stacks would be arranged in a way that maximized space, utilizing the entire interior of the orbiter.
The VOIDS themselves would be hollow spherical cones with packed instrumentation. The external shell would feature two gridded air slots, which would open during descent due to atmospheric drag, allowing the internal sensors to measure the outside conditions while remaining protected. The VOIDS would descend with the flat side facing downward to minimize atmospheric drag, while the rounded bottom would have a thicker shell to offer additional protection, similar to the heat shields on astronaut reentry capsules.
These ideas were refined through collaboration, with the use of weighted decision matrices to evaluate and compare other potential designs. Two of these decision matrices are provided below to demonstrate how we systematically weighed each idea’s effectiveness and feasibility.
VOID Ejection Method
VOID Design
This marked the conclusion of the design phase of our project. Following this, we compiled a detailed 73-page report outlining our entire process, which included sections on potential future changes and lessons learned. In addition to the report, we scripted and recorded a concise explanatory video aimed at breaking down our entire project in an engaging, informal format. The video is available below.
Skills Learned & Applied
Skills Learned & Applied
Spending an entire semester on this project provided me with invaluable insights into the space mission design process. There are numerous factors to consider, especially when making initial decisions. Stakeholders for such missions can range from the general public to government agencies and private companies, each with their own specific interests and goals. As an engineer, my objective is to meet as many of these requirements as possible, as they are the ones contracting me for the job.
Additionally, this project taught me just how challenging it is to get mass to space. Even small amounts of mass add up to an enormous final rocket mass. This experience was the perfect complement to the coursework for this class and helped me apply the theory we were learning. My favorite part of the design process was defining the orbital parameters and calculating the ΔV values for the mission.
One key lesson I learned that is incredibly useful during the design stages of any project is the importance of concept design reviews. These reviews provide valuable external feedback from both academic and industry experts, which can significantly improve the quality of my work by applying the intuition and experience I might not yet have.
Finally, and most importantly, space is hard. It presents immense challenges, and engineers must answer highly specific and complex questions. But that's the beauty of mission design. It's all up to you to make the best decisions. This project was truly inspiring for me, as it aligns perfectly with my career aspirations as an astronautical engineer. My dream is to see my ideas come to life in space exploration, contributing to the advancement of humanity's understanding of the universe.
Technical Skills
Siemens NX
SolidWorks
MATLAB
Data Analysis (Microsoft Excel & MATLAB)
Technical Writing
Mission Design Theory
Orbital Mechanics
Personal Skills
Teamwork
Time Management
Creativity and Originality
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