What are RTGs, made for the most distant spaceships of us, and why are they so important? NASA’s Voyager mission may explain to us.
Feeding solar spatial naves may not seem like a challenge given the intensity of sunlight on earth. Space ships near Earth use large solar panels to obtain the electricity necessary for the functioning of their communication systems and scientific instruments.
Space ships have to support intense sunscreens, radiation and temperature variations of hundreds of degrees below zero to hundreds of degrees above zero, the engineers developed Innovative solutions To feed some of the most remote and isolated space missions.
Os RTGs They are essentially batteries fed by nuclear energy. But unlike the AAA batteries of their television command, RTGs can provide energy for hundreds of millions or thousands of miles from Earth for decades.
Nuclear
Thermoelectric generators of radioisotopes do not depend on chemical reactions such as the piles of your mobile phone. Instead, they are based on the radioactive decay of elements to produce heat and eventually electricity. Although this concept seems similar to that of a nuclear center, RTGs function according to a different principle.
Most RTGs are built using PLUTONIO-238 As a source of energy, which is not usable in nuclear power plants, since it does not support fission reactions. Instead, the -238 is an unstable element that will suffer radioactive decay.
O radioactive decay, or nuclear decay, It occurs when an unstable atomic nucleus emits spontaneous and randomly particles and energy to achieve a more stable configuration. This process causes the element to transform often on another element, since the core may lose protons.
When the plutonium-238 decays, emits Alfa particleswhich consist of two protons and two neutrons. When the 238 plutonium, which begins with 94 protons, releases an alpha particle, loses two protons and becomes uranium-234, which has 92 protons.
These alpha particles interact and transfer energy to the material surrounding the plutonium, heating this material. The radioactive decay of the 238 plutonium releases enough energy so that it can shine in red Due to its own heat, and it is this powerful heat that constitutes the source of energy to feed an RTG.
Heat as energy
Thermoelectric generators of radioisotopes can transform heat into electricity using a principle called SEEBECK effect, discovered by German scientist Thomas Seebeck in 1821. As an additional benefit, the heat of some types of RTGs can help maintain electronics and other components of a mission in hot space hot and function well.
In its basic form, the SEEBECK EFFECT It describes how two wires of different conductive materials united in a loop produce a chain in this loop when exposed to a temperature difference.
Devices that use this principle are designated by Thermo -ethical pairs, or thermocouples. These thermocouples allow RTGs to produce electricity from the temperature difference created by the heat of the decay of the 238 plutonium and the cold cold of the space.
Conception of the thermoelectric radioisotopes generator
In a thermoelectric generator of basic radioisotopes, it has a 238 plutonium container, stored in the form of plutonial dioxide, often in a solid ceramic state that provides extra safety in the event of an accident. The plutonium material is surrounded by a protective layer of insulation sheet to which a large set of thermocouples. The whole set is within an aluminum protective enclosure.
The interior of the RTG and one side of the thermocouples are kept hot – close to 1,000 degrees Fahrenheit (538 degrees Celsius) – while the exterior of RTG and the other side of thermocouples are exposed to space.
The strong temperature difference allows an RTG Transform the heat of radioactive decay into electricity. This electricity feeds all kinds of spaceships, from communications systems to scientific instruments and Rovers on Mars, including five current NASA missions.
The true advantage of RTGs is their ability to provide predictable and consistent energy. The radioactive decay of the plutonium is constant – every second of every day for decades. Over the course of about 90 years, only half of the RTG plutonium will have decayed. An RTG does not need moving parts To generate electricity, which makes it much less likely to break or stop working.
In addition, they have excellent safety registration and have been designed to survive their normal use and also to be safe in case of an accident.
RTGS in action
The RTGs have been fundamental to the success of many of the solar system and NASA’s deep space. And no mission captures the power of RTGs as the Voyager missions.
The probes Travel 1 th travel 2 There are about 15.5 billion miles and 13 billion miles (almost 25 billion kilometers and 21 billion kilometers) from Earth, respectively, which makes them the Human objects more distant ever. Even at these extreme distances, their RTGs continue to provide them with consistent energy.
These spaceships are a testimony of the engineers’ mill that conceived the first RTGs in the early 1960s.
