The Journey to Psyche Exploration Begins! The Target is More Than Just the "Golden Planet"

At 22:19 Beijing time on October 13, the US Falcon Heavy rocket lifted a probe into space from the Kennedy Space Center, and the romantic journey to explore Psyche began. This probe has the same name as Psyche, and its target is the much-anticipated "golden planet". It is planned to carry out a mission of at least 8 years. So what is the charm of Psyche in the minds of scientists? In order to complete its mission, what "special skills" does the probe have? What results can scientists expect from this mission?

Falcon Heavy rocket launches probe

The hidden secret of “gold attribute”

Scientists have discovered that Psyche is an asteroid that is almost entirely made of metal, with rich reserves of various rare metal minerals. Some people have given Psyche a valuation of up to 100 billion US dollars and given it the title of "Golden Planet".

In fact, what attracts scientists to Psyche is far more than its "golden properties". Scientists believe that Psyche is likely to be the only celestial body in the solar system that is completely composed of a core. In other words, it gives humans a rare opportunity to directly observe and study the core of a planet. Obviously, compared with existing indirect detection methods, direct observation is expected to better help scientists study the internal composition of celestial bodies, summarize the laws of celestial evolution, and then reveal the secrets of the Earth's core by analogy.

Psyche is nicknamed the "Golden Planet"

Therefore, NASA proposed five main goals for the Psyche exploration mission:

First, it is necessary to confirm whether Psyche evolved from the remnant core of a celestial body or was formed from unmelted matter.

Second, determine the relative age of various regions on the surface of Psyche.

Third, find out whether these small metallic objects contain so-called "light elements." Scientists believe that such substances are widely present in the high-pressure core of the Earth.

Fourth, study the formation environment of Psyche, especially whether it is more oxidizing or more reducing compared to the Earth's core.

Fifth, describe the surface terrain features of Psyche.

To achieve these goals, NASA has invested more than $1.1 billion in the development of the probe, planning an exploration journey that will last at least eight years. According to the latest estimates, if the probe is launched in mid-October this year, it will attempt to fly over Mars and enter the asteroid belt between 2023 and 2026. If all goes well, the probe will likely take about three years to adjust its route and reach the orbit of Psyche around 2029, with a total voyage of about 3.6 billion kilometers. Then, the probe is expected to fly around Psyche between 2029 and 2031, conducting 26 months of scientific mapping and research.

The probe is bound to face many challenges in completing this journey. The first is likely to be the long-term maintenance of power and energy supply. The second is the communication problem during the long journey. After all, the probe needs to maintain reliable and high-quality communication with the earth at an ultra-long distance and transmit data efficiently and accurately. In addition, the adaptability problems brought about by the peculiar structure and potato-like shape of Psyche cannot be ignored. This will determine whether the probe can safely approach Psyche and collect scientific data.

Advanced equipment has highlights

In order to ensure the completion of long-term missions in harsh environments, the probe is equipped with various advanced equipment, striving to overcome the "ninety-nine eighty-one difficulties" on the journey.

Overall, the probe consists of a solar electric propulsion system, flight computer, sensors, and flight laser transceiver, many of which are innovative.

The first is the largest main structure of the probe - the solar electric propulsion system, which is mainly composed of two solar arrays, a system chassis, a propulsion tank, etc. Among them, the cross-shaped solar array composed of five panels is equivalent to the size of a tennis court when unfolded, setting a record for the largest solar array ever deployed by NASA's Jet Propulsion Laboratory.

The huge array is mainly used to meet the power needs of the probe in the low-light environment of deep space far away from the sun. It can not only maintain the operation of scientific instruments and equipment, but also drive the electric propulsion device to support the probe's "long journey". It is worth noting that the so-called "super-efficient" solar electric propulsion system is one of the innovative technologies used in the probe, and the core equipment is the Hall thruster. This trip to explore Psyche is also the "first show" of the spacecraft driving the Hall thruster in space outside the lunar orbit.

Schematic diagram of the Psyche probe deploying its solar array

Next, it is necessary to understand the "brain" of the probe - the flight computer. Due to the strange shape of Psyche, scientists speculate that it may have a very irregular gravity field. Therefore, when designing the probe, more efforts must be made in the field of navigation and control to ensure that it can safely operate in an orbit far away from Psyche and accurately measure the gravity field of Psyche. Then, by modeling and improving the gravity field model in real time, a control strategy is formed to make the orbit of the probe continue to descend and slowly approach Psyche.

The guidance, navigation and control software used by the flight computer will play a critical role in this process. It will help the probe's antenna point accurately to the Earth in order to transmit data and receive commands from the mission control system. This type of software is not only crucial in controlling the direction of the probe's flight, but is also essential for the solar electric propulsion system to work.

Then, the "eyes" and "tentacles" of the probe will take on the heavy responsibility. They are various sensors, including magnetometers, multispectral imagers, gamma-ray and neutron spectrometers. Among them, the magnetometer is used to measure the magnetic field of Psyche. The multispectral imager is used to obtain sufficiently high-resolution images of the surface of Psyche, assist in identifying the metal, silicate and other material components on the surface of Psyche, and then collect geological and topographic data. Gamma-ray and neutron spectrometers are the "main force" for identifying chemical elements on the surface of Psyche, and the data obtained will help draw a map of the material composition of Psyche. There is also a microwave radio communication system for high-precision measurement of Psyche's gravity field and collecting clues about its internal structure.

Finally, the "mouth" and "ears" of the probe are equally important. Their scientific name is flying laser transceivers, which together with ground-based laser receivers form a deep space laser communication system, which is expected to increase the efficiency of information transmission in deep space exploration missions by geometric multiples.

“Pathfinders” take on important tasks

From the composition of the equipment, it is not difficult to find that the Psyche probe is responsible for the practical verification of a number of new aerospace technologies.

For example, after the Hall thruster "captures" active electrons in the magnetic field, it uses the electrons to fully ionize the propellant to obtain efficient power. It is generally believed that this type of thruster consumes less propellant than chemical thrusters of the same thrust, and its design is simpler than the ion thrusters commonly used in existing electric propulsion technology. It can be said that based on the Hall thruster, scientists and engineers are expected to develop lighter, smaller and more economical spacecraft to meet the needs of long-term deep space exploration missions.

Psyche probe undergoes testing before launch

Deep space laser communication technology uses near-infrared wavelength photons (rather than radio waves) to encode data, and undertakes the task of efficient communication between deep space probes and the Earth. According to estimates, compared with current radio communication systems of the same size and power, laser communication systems are expected to increase the data transmission rate of space flight missions by 10 to 100 times, making it possible for probes to transmit higher-resolution images and larger volumes of scientific data to the Earth, significantly improving the level of deep space communication.

NASA plans to verify the technology through this exploration of Psyche. The main test will be carried out in the early stage of the probe's cruise phase, which will last about 1 year. In 2014, NASA used lasers to transmit high-definition video from the International Space Station back to the ground. In deep space without the interference of atmospheric refraction and scattering, laser communication will undoubtedly play a more significant advantage. As NASA's most distant high-bandwidth laser communication test in history, the Psyche probe has the potential to revolutionize aerospace communication technology and apply it to the next frontier - deep space.

Although the Psyche exploration program encountered many technical difficulties and management problems, which led to repeated delays, NASA's persistence in exploring Psyche has not wavered. The reason is certainly not only the desire for the rare metal resources on Psyche...

On the one hand, if the probe can obtain a large amount of important data on Psyche's elemental composition, gravitational field distribution, geological topography, etc., it is expected to provide scientists with a large amount of valuable information, gain a deeper understanding of the planet's internal structure and evolution process, and thus help answer questions about the Earth's core and the formation of the solar system.

On the other hand, the Psyche exploration project will provide valuable practical experience for a number of new technologies, and the feedback from the results may help future deep space exploration to achieve leapfrog progress. It is not only expected to obtain more detailed information from more distant celestial bodies, but also may help humans perform more complex and more profitable deep space missions. In the future, when space mining and other aerospace economies are scaled up and normalized, people may remember the Psyche probe as a "pioneer" in technology and engineering practice.

In short, regardless of the success or failure of the mission, the Psyche probe has demonstrated mankind's beautiful wish to explore deep space. (Author: Art Image source: NASA's review expert: Jiang Fan, deputy director of the Science and Technology Committee of China Aerospace Science and Technology Corporation)