Adventure on Mars
The desire to know the universe was the engine for a series of technological advances, the proberockets, whom we impose the mission to look beyond our planet.
The search is an adventure bigger every kilometer driven in a space that is considering infinite. A new search module is now landed in the soil of the planet that has undergone more speculation since the “conquest” of the Moon, Mars . Image below shows the Generator used in nuclear MMRTG Curiosity Mars robot.
Curiosity is an unmanned vehicle that was developed by North American Space Agency (NASA) to collect samples and images of the soil and the atmosphere of the red planet, as well as analyze and investigate possible evidence that at some point could have been life on the planet .
This is achieved by using highly sophisticated equipment and high accuracy, all coupled to the vehicle structure – the full name of the adventure is MSL ( Mars Science Laboratory ), and Mars Science Laboratory: Robot Curiosity has on board a complete laboratory, which will analyze the samples collected by its robotic arm.
Unlike previous Mars rovers, powered by solar panels and batteries, the Curiosity is more a curiosity: a source of nuclear energy.
Nuclear power in space
The development of secure systems that provide energy to power equipment such as Curiosity is crucial when it comes to such a hostile environment in which the surface of a strange planet. Not to mention the distance that prevents any kind of maintenance more complex by scientists here on Earth.
Thinking about the lifetime of Curiosity, NASA implemented a system to produce power and heat based on nuclear energy.
Not that this is something new in the field of space missions, after all, the first module to load a nuclear device was released on April 14, 1969, Nimbus III mission.After this successful enterprise, we had over 16 missions, including the latter to Mars.
The importance of a system that is capable of providing power and heat equipment is of utmost importance, and it must be completely independent of weather conditions and external. In this case, a small set of devices became the basis for generating energy to power the Curiosity the next two years of work.
The system used in this mission, developed exclusively for her, is called Radioisotope Thermoelectric Generator Multi-Mission (MMRTG, English Multi-Mission Radioisotope Thermoelectric Generator ).
It comprises a series of devices work together to generate heat of reaction from the natural decay of the isotope of Pu-238. Its design was created so that it can be operated in conditions of extreme vacuum of space or atmosphere of a planet.
The devices work to manage the heat liberated in nuclear decay reactions and generate, by means of thermoelectric conversion modules (thermocouples), the electricity needed to operate the vehicle and its equipment.
The thermonuclear energy is produced within the GPHS modules ( General Purpose Heat Source ).
Each module contains sets of ceramic pellets of plutonium-238 dioxide (PuO2-238), responsible for feeding the nuclear reactions in a total of 4.8 kg of the substance.
These inserts are encapsulated in a protective made of iridium.The capsules are then stored fuel in a box covered with tubes formed from carbon fiber, and then placed in GPHS modules.
Each GPHS module is designed to work separately, providing heat up to 250 watts, but can also be grouped to work together, forming stacks ( stacks ).
The modules used in Curiosity have dimensions of 4 cm X 4 cm X 2 cm each, weighing about one pound and medium. Its engineering construction designed to give priority to the security system, avoiding leakage of radioactive material even possible accidents involving the vehicle.
The generator system has MMRTG operational efficiency 6-7% and can produce up to 110 Watts total electric power. The heat supplied by the generator is a feature that makes the assembly appropriate for maintenance of the vehicle.
Computers and analyzers need to be in a temperature range of operation to be kept constant, regardless of extreme variations in temperature of the planet – the heat will come from the decay process of plutonium stored in the modules, while maintaining the thermal stability of the equipment.
Despite the mission with the Curiosity have a finish time calculated for 687 Earth days, the power generator can be kept open for about 14 years.