Stock Types 1 and Radioisotope Thermoelectric Generators (RTGs)
A look at the different types of stocks and NASA's solution to power in deep space
Stock Types
Most people know that stocks are shares in a company. The more shares you have, the more control and profit you get. While this may seem simple enough, stocks can be divided into a multitude of different categories that each focus on different things. These terms come from Investopedia, a website that educates the reader on everything related to finance that I highly recommend checking out.
Common Stock: This is just another name for ordinary stocks. They are what most people think about, which is the more you own, the more control you have.
Preferred Stock: This type of stock allows the holder to receive dividends, like Income Stocks. However, you will also get paid first in a bankruptcy. You do not gain any power with owning it, just consistent cash flow.
Growth Stock: Stocks that are expected to grow at a rate the exceeds that of the standard stock market.
Value Stocks: These stocks trade at a discount to what the company might be performing at. Most of the companies with this type of stock are those that outperform the market when the market is down, like energy and healthcare.
Income Stocks: These stocks are given to holders as part of the company’s profit. Risk averse investors who want passive income usually buy these.
Blue-Chip Stocks: These are stocks that belong to a massive long term established company, like McDonalds, Walmart and Microsoft.
Radioisotope Thermoelectric Generators (RTGs)
Most people are familiar with power generation like solar power and hydroelectric power. These are straight forward. Flowing water turns a turbine to create electricity, or the sun shines on a panel and this creates power. But there is a type of electricity that not many people know about, yet is crucial for deep space exploration. This energy is used in Radioisotope Thermoelectric Generators (RTGs). The easiest way to describe it is that the source of electricity is heat. There is a phenomenon, called the Seebeck Affect, where if 2 different metals with different semiconductive principles are heated to different temperatures, then they will produce an electrical current. While this may sound confusing, essentially, if you had a steel and copper wirer tied together in a circle and heated one of the wires, an electrical current would begin passing through them. Since the vacuum of space is cold, all that needs to be produced is a constant source of heat. You might think that this would require electricity, thereby negating the purpose of generating electricity, but there are materials that, in their natural state, generate heat.
Plutonium-238 is the magic material needed. Plutonium-238 is unstable and constantly emits radiation in the form of alpha radiation until it becomes Uranium-238. This alpha radiation emits a lot of heat. Looking back at the Seeback Affect, this means that you can generate constant, consistent energy for a spacecraft no matter where in the solar system you are. The voyager probes, which are in the process of leaving this solar system used this type of energy generation. These probes were launched in the late 1970s are still able to transmit back to NASA. Over time the Plutonium will become less efficient, since it slowly decays back to Uranium. That is why the voyager probes will at some point die. The long lasting power these generators supply and the fact that there are no moving parts, mean that Radioisotope Thermoelectric Generators (RTGs) will remain a popular choice for probes exploring the edge of our solar system. However, there is work being done to make a more efficient type of radioisotope power… to be cont.
The voyager Probes RTGs
Voyager 1 cross section
resources:
https://www.investopedia.com/types-of-stocks-5215684
https://nasaeclips.arc.nasa.gov/video/launchpad/launchpad-what-are-radioisotope-power-systems