BY STARDUST

Our Rechargeable Storage Project for Nasa Space Apps Challange by Team StarDust

"Somewhere, something incredible is waiting to be known."

About NASA Space Apps Challange

The NASA International Space Apps Challenge (Space Apps) is an international hackathon for coders, scientists, designers, storytellers, makers, builders, technologists, and others in cities around the world, where teams engage the National Aeronautics and Space Administration’s (NASA’s) free and open data to address real-world problems on Earth and in space.

Each October, over the course of two days, Space Apps brings participants from around the world together at hundreds of in-person and virtual local events to solve challenges submitted by NASA experts. After the hackathon, project submissions are judged by space agency experts and winners are selected for one of 10 Global Awards.

Since its inception in 2012, NASA’s International Space Apps Challenge has engaged 180,000+ registrants from 150+ countries/territories in using NASA’s open data to build innovative solutions to challenges we face on Earth and in space.

OUR CHALLANGE

Our challenge is to design an energy storage system that will power a surface lander or rover on the surface of Venus for at least 60 days, so that there is a viable energy storage capability for long-duration exploration missions.

For in situ planetary exploration missions, energy is required to power scientific instruments, gather and process the data collected, and communicate the results back to Earth. Energy is also often required to move a vehicle on the surface. Batteries are typically used to store and deliver this energy. However, currently available batteries cannot operate in the extreme environment on the surface of Venus. The temperature is extremely hot (~460 C) and the high-pressure atmosphere (~93 bar) contains caustic chemicals (SO2, HCl, HF). Exposed to these conditions, common batteries would rapidly fail. All previous missions to the surface of Venus have been designed to operate for short durations (less than two hours). In those missions, the components were contained in a pressure vessel, which eventually heated up to a temperature at which the components could no longer operate and the mission ended.

VENUS

Venus is the second planet from the Sun and is Earth’s closest planetary neighbor. It’s one of the four inner, terrestrial (or rocky) planets, and it’s often called Earth’s twin because it’s similar in size and density. These are not identical twins, however – there are radical differences between the two worlds.

Venus has a thick, toxic atmosphere filled with carbon dioxide and it’s perpetually shrouded in thick, yellowish clouds of sulfuric acid that trap heat, causing a runaway greenhouse effect. It’s the hottest planet in our solar system, even though Mercury is closer to the Sun. Surface temperatures on Venus are about 900 degrees Fahrenheit (475 degrees Celsius) – hot enough to melt lead. The surface is a rusty color and it’s peppered with intensely crunched mountains and thousands of large volcanoes. Scientists think it’s possible some volcanoes are still active.

DaVinci Probe

OUR IDEA

With our research, we thought up an energy system which produces energy by making use of Venus’s atmospheric pressure. Our system is designed to be able to last for long periods of time under critical conditions. We planned to achieve this by using piezoelectric materials to generate energy while protecting the energy generators and batteries with titanium and aerogel. Titanium protects the system from high atmospheric pressures and aerogel provides heat insulation to preserve the batteries. There is also microgap cooling technologies installed inside the protective layers to keep the batteries’ capacity to a maximum.

The main goal of our project is to propose an energy generating and storing system which will allow a surface rover to last on Venus for at least 60 days. To achieve this, we researched for 3 main aspects: How we could generate the energy required for this mission, where the generated energy would be stored, and how the entire system could be protected from the extremely high pressure and temperature of Venus.
To continously generate energy for the rover, piezoelectric generators can be used. These generators essentially make use of the pressure applied unto them to generate electricity. With the generator being placed in a special compartment designed to allow it to be exposed to Venus’s 93~ bar atmospheric pressure, it will be able to constantly produce a sufficient amount of energy.
These generators will then transfer the produced energy to lithium-ion batteries which are widely used in space misssions. These batteries are rechargable and therefore our choice for the system.
To prevent the batteries from growing ineffective because of Venus’s temperature, the entire system will be covered by silica-aerogels. Silica-aerogels are extremely good heat insulators and will help with helping the system from overheating. On top of that, there will also be microgap-cooling technologies installed with the system to cool it down whenever it’s necessary.
Lastly, to protect the system from collapsing under the pressure of Venus’s atmosphere, all of these materials will be put inside a protective layer of titanium. Titanium is one of the matters that are the strongest against pressure. It’s also not as dense as it’s alternatives and therefore the best choice to keep mass to a minimum.

MORE DETAILS ABOUT MATERİALS

AEROGEL (Insulation)

We used aerogel as the insulation system in our rechargeable energy storage project because; Aerogel is the world's lightest and lowest-density solid, with 99%, almost all, air. The surface area of only one gram can increase from 250 m2 to 3000 m2. In other words, you can spread 2-3 cm3 of aerogel over an area larger than a football field. This low density of aerogel allows it to be used as a very light material, while its very large surface area makes it a super-insulating solid material. With these features, aerogels offer a wide range of uses from space studies to ornaments.
Aerogels are a class of synthetic porous ultralight material derived from a gel, in which the liquid component for the gel has been replaced with a gas, without significant collapse of the gel structure. The result is a solid with extremely low density and extremely low thermal conductivity. Aerogels can be made from a variety of chemical compounds. Silica aerogels feel like fragile expanded polystyrene to the touch, while some polymer-based aerogels feel like rigid foams.
The first documented example of an aerogel was created by Samuel Stephens Kistler in 1931, as a result of a bet with Charles Learned over who could replace the liquid in "jellies" with gas without causing shrinkage.
Aerogels are produced by extracting the liquid component of a gel through supercritical drying or freeze-drying. This allows the liquid to be slowly dried off without causing the solid matrix in the gel to collapse from capillary action, as would happen with conventional evaporation. The first aerogels were produced from silica gels. Kistler's later work involved aerogels based on alumina, chromia and tin dioxide. Carbon aerogels were first developed in the late 1980s.

TITANIUM (Outer Plating Metal)

Big Title

We used titanium as the outer plating metal ; Titanium is a very strong metal that is used in special applications. The most common isotope has 26 neutrons. Titanium was discovered in 1791 by William Gregor. It is chemical element number 22 on the periodic table. Its symbol is Ti. It has 22 electrons and 22 protons. Its name comes from the name of the strong Greek gods called titans.
Titanium can combine with other chemicals to make different materials. When titanium mixes with oxygen from the air, it forms titanium dioxide (TiO2), or titania, which forms a shell around the metal and prevents chemicals from damaging it. Titanium dioxide is a white pigment that is often used to make things less transparent, brighter, or rougher - because it does not react with chemicals inside the human body, it is safe to use in foods and other applications, like toothpaste.
Titanium alloys are used in aerospace engineering to make very strong and light parts of aeroplanes. These alloys can replace steel because they are almost as strong as steel but much lighter. They are also much stronger than aluminium alloys, but only a little heavier, meaning that titanium parts can be thinner and lighter, while still withstanding the same forces. It does not corrode in most conditions, even when exposed to sea water or chlorine. However, it can burn at high temperatures, and like many metal powders, titanium dust is extremely flammable.

Some other properties of Titanium include:
• Excellent heat transfer properties
• High melting point - 3,135 degrees Fahrenheit (This is 400 degrees above the melting point of steel and 200 degrees above that of aluminum)
• A high degree of resistance to minerals, acids, and chlorides
• Non-toxic - Makes it a candidate for use in medical devices that are inserted in the human body
• High-degree of electrical resistance

LITHIUM-ION (Battery)

We used lithium-ion as a battery because ; A lithium-ion battery or Li-ion battery is a type of rechargeable battery composed of cells in which lithium ions move from the negative electrode through an electrolyte to the positive electrode during discharge and back when charging. Li-ion cells use an intercalated lithium compound as the material at the positive electrode and typically graphite at the negative electrode. Li-ion batteries have a high energy density, no memory effect (other than LFP cells) and low self-discharge. Cells can be manufactured to prioritize either energy or power density. They can however, be a safety hazard since they contain flammable electrolytes and, if damaged or incorrectly charged, can lead to explosions and fires.
M. Stanley Whittingham discovered the concept of intercalation electrodes in the 1970s, and invented the first rechargeable lithium-ion battery, which was based on a titanium disulfide cathode and a lithium-aluminum anode, patented in 1977, and assigned to Exxon. John Goodenough expanded on this work in 1980 by using lithium cobalt oxide as a cathode. A prototype Li-ion battery was developed by Akira Yoshino in 1985, based on the earlier research by John Goodenough, M. Stanley Whittingham, Rachid Yazami and Koichi Mizushima during the 1970s–1980s, and then a commercial Li-ion battery was developed by a Sony and Asahi Kasei team led by Yoshio Nishi in 1991. Lithium-ion batteries are commonly used for portable electronics and electric vehicles and are growing in popularity for military and aerospace applications.
Chemistry, performance, cost and safety characteristics vary across types of lithium-ion batteries. Handheld electronics mostly use lithium polymer batteries (with a polymer gel as electrolyte), a lithium cobalt oxide (LiCoO2) cathode material, and a graphite anode, which together offer a high energy density. Lithium iron phosphate (LiFePO4), lithium manganese oxide (LiMn2O4 spinel, or Li2MnO3-based lithium rich layered materials, LMR-NMC), and lithium nickel manganese cobalt oxide (LiNiMnCoO2 or NMC) may offer longer lives and may have better rate capability. Such batteries are widely used for electric tools, medical equipment, and other roles.
NMC and its derivatives are widely used in the electrification of transport, one of the main technologies (combined with renewable energy) for reducing greenhouse gas emissions from vehicles. Improperly recycled batteries can create toxic waste, especially from toxic metals and are at risk of fire. Moreover, both lithium and other key strategic minerals used in batteries have significant issues at extraction, with lithium being water intensive in often arid regions and other minerals often being conflict minerals such as cobalt. Both environmental issues have encouraged some researchers to improve mineral efficiency and alternatives such as iron-air batteries.
Research areas for lithium-ion batteries include extending lifetime, increasing energy density, improving safety, reducing cost, and increasing charging speed, among others. Research has been under way in the area of non-flammable electrolytes as a pathway to increased safety based on the flammability and volatility of the organic solvents used in the typical electrolyte. Strategies include aqueous lithium-ion batteries, ceramic solid electrolytes, polymer electrolytes, ionic liquids, and heavily fluorinated systems.

PIEZOELECTIRICIY(Energy Sourses)

We used piezoelectiricity as an energy source because piezoelectricity (also called the piezoelectric effect) is the appearance of an electrical potential (a voltage, in other words) across the sides of a crystal when you subject it to mechanical stress (by squeezing it).
In practice, the crystal becomes a kind of tiny battery with a positive charge on one face and a negative charge on the opposite face; current flows if we connect the two faces together to make a circuit. In the reverse piezoelectric effect, a crystal becomes mechanically stressed (deformed in shape) when a voltage is applied across its opposite faces.
Using this property of the crystals, we use them in our system. The way they can produce energy this way in Venus is, by making use of its geography. Venus is a planet filled with hundreds of active volcanoes. These volcanoes cause many earthquakes and storms. When our system is exposed to these movements, a titanium plate placed on top of the piezoelectric generators will vibrate and transfer that to the generators. This way, there will be a constant way to generate energy.

MICROGAP COOLING SYSTEM

We used microgap cooling system because; With microgap cooling, heat generated by tightly packed electronics is removed by flowing a coolant — in this case, a fluid called HFE 7100 that doesn’t conduct electricity — through embedded, rectangular-shaped microchannels within or between heat-generating devices. As the coolant flows through these tiny gaps, it boils on the heated surfaces, producing vapor. This two-phase process offers a higher rate of heat transfer, which keeps high-power devices cool and less likely to fail due to overheating.
The embedded cooling approach represents a significant departure from more traditional cooling technologies. With more conventional approaches, designers create a “floor plan.” They keep the heat-generating circuits and other hardware as far apart as possible. The heat travels into the printed circuit board, where it is directed eventually to a spacecraft-mounted radiator.