Now, let's get back to reality. Compared with dark matter and dark energy, asteroids are easier to detect and more worthy of detection than Pluto and Kuiper Belt objects ... Planetary scientists have found that the origin of life on earth may come from an ultra-old lake, not an ancient ocean. Where did the water of the ancient earth come from? In fact, water and primitive life are likely to be related to asteroids. Primitive life is inseparable from the help of asteroids. There are many water resources on asteroids, especially comets ... these small celestial bodies have played a certain role in the formation of life on earth.
In other words, asteroids are like machines that spread life. In fact, in addition to studying the origin of life on earth, asteroids can also study the early state of the solar system and the origin of the sun. It is through asteroids that astronomers understand that the sun was born in a dusty disk and will become a white dwarf in the future.
Whether it is economic value or research value, the charm of asteroids is no less than that of Mars and the moon. This is our asteroid. Next, let's take a look at the asteroid detector technology, which is a difficult space exploration field today. Why? We can look at three different stages of asteroid detectors and enjoy the most advanced asteroid detection technology at this stage.
First, let's take a look at the Rosetta asteroid probe, which is the third mission of the European Space Agency's Horizon project in 2000, aiming to rendezvous with comet 67 P Gramenko. From the beginning of the mission, the European Space Agency planned to place a probe on the ground to study comets from orbit and fly over at least one asteroid during the flight. The main purpose of Rosetta asteroid detector is to study the origin of comets, the relationship between comets and interstellar matter and its influence on the origin of the solar system.
In fact, there are many studies on asteroids, such as the overall characteristics of asteroid cores. Do you think only planets have cores? In fact, some asteroids also exist. In addition, the dynamic properties, surface morphology and composition of asteroids are also determined, which is very important for studying the origin of the sun. It can be said that these asteroids are fragments. If they are successfully collected, the mystery of the solar system and the origin of the sun can be solved.
Rosetta asteroid detector will also study the chemical, mineralogical and isotopic composition determination of volatiles and refractories in comet nucleus. The probe will also study the interaction between dust and gas on the surface and inside of the asteroid to study the asteroid itself and determine how to capture it more effectively for human use in the future. A word from human beings: Know yourself and know yourself, and win every battle. It is also possible to use it on celestial bodies.
The design of Rosetta asteroid detector is based on the box-shaped central frame, 2.8m x 2. 1m x 2.0 and the aluminum honeycomb main platform. The total weight is 3000 kg, including 100 kg lander and 165 kg scientific instrument. Two solar panels, each 32 square meters. The spacecraft consists of two main modules, one is the payload support module PSM for carrying scientific instruments, the other is the payload support module PSM of two payload arm deployment mechanisms installed at the top of the frame, and the other is the bus support module BSM and other loads.
We can look at the general structure of the Rosetta asteroid detector. First of all, it is a steerable 2.2m diameter parabolic antenna with high gain. The lander is installed opposite the antenna, and the scientific instrument panel is installed at the top. It is designed to face the comet continuously in orbit, while the antenna and solar panels face the earth and the sun. Radiators and louvers are installed on the back and side plates, facing the sun and comets. Protruding from the center of the spacecraft, from the bottom is a vertical thrust tube, which is fixed on the reinforcing ring with corrugated aluminum.
The driver of the "Rosetta" asteroid probe provides mobile propulsion function, which consists of two 1 106 liter propellant tanks, which are filled with propellant and oxidant. A total of 660 kg of propellant (the propellant is monomethyl hydrazine) and 1060 kg of oxidant (the oxidant is nitrogen tetroxide) are needed. This can help the Rosetta asteroid detector to brake flexibly in the comet 67p orbit, which is actually one of the standards of the asteroid detector.
Next, let's look at other loads. The launch mass of the spacecraft including fuel is 2900 kg. And four 35-liter pressure tanks. The type of spacecraft stabilization system is three-axis stabilization, the direction is controlled by 24 10N thrusters, and the attitude uses two trackers, a sun sensor, a navigation camera and three laser observation modules. Solar cells are composed of low-intensity and low-temperature silicon or GaAs solar cells.
The data detected by Rosetta asteroid detector, the observed images and so on need to be transmitted back to Earth, so the return antenna of the detector is very important. The antenna power is stored in four 10 Acher nickel-cadmium batteries, which will provide 28V bus power. Communication is realized by a high gain antenna, a fixed 0.8m medium gain antenna and two omnidirectional low gain antennas, and the transmission rate is at an excellent level. Rosetta asteroid detector will use S-band remote control uplink and S-band and X-band telemetry scientific data downlink. The Rosetta lander named Philae will be connected to one side of the Rosetta spacecraft and released some time after Rosetta reaches the orbit of the comet.
Rosetta was launched from Kourou Space Center in French Guiana at 07: 17 UTC on March 2, 2004. The spacecraft then entered the heliocentric orbit and carried out earth flight and gravity assistance on March 4, 2005. On February 25, 2007, flying over Mars and gravity boosting were completed in one go. In 2007165438+1October 13, and in 2009165438+1October/0/3, the Mars gravity boost was completed twice.
On September 5th, 2008 18: 58 UTC, Rosetta flew within 800 km of the asteroid at a relative speed of 8.6 km/s, and the spacecraft entered the hibernation phase on June 20th11. 20 14 65438+1On October 20th, Rosetta came out of hibernation and joined the comet on August 6th, 2014.
The interactive maneuvering system reduces the speed of the spacecraft relative to the comet to about 25m/s, and enters the stage of near-comet drift. After a while, observations of comets and distant orbits began. This stage lasts about 90 days. At the end of this phase, the Rosetta asteroid detector is located opposite the asteroid.
Rosetta is funded by the European Space Agency. Before the launch was delayed, the total cost of the mission, including launch and operation, was about $900 million. This mission was originally intended to rendezvous with comet 46 P/Wirtanen. The mission was postponed because of something wrong with Ariane booster.
Undoubtedly, the Rosetta Asteroid Detector of the European Space Agency is one of the pioneers of human asteroid exploration, and its data brought human eyes to asteroids for the first time. At first, the word "small but fine" is the best description of the probe ... Next, let's take a look at NASA's OSIRIS-Rex asteroid exploration mission, which is also an excellent asteroid exploration mission.
At first, no one supported the asteroid exploration mission. At a public meeting, NASA explained how to use a tool called OSIRIS-Rex laser altimeter OLA to scan the surface of the Benoit asteroid. The instrument draws a 3D image of the hard surface emitted by the laser, which enables NASA researchers to see the rocky surface of the asteroid in detail.
Next, NASA explained the most dangerous operation of the probe landing site, as well as the short landing and sample collection. Landing in an area with too much rubble may be disastrous for the probe, which will damage the spacecraft itself and may damage one of its main targets.
The detection paths are different. After many years, the detection methods of OSIRIS-Rex asteroid detector are more and more advanced. OSIRIS-Rex 3D laser model provides a special 3D model for NASA team. Avoiding some huge boulders is the key, but because the surface of the asteroid Benu bird can't bear to look straight, there are too many fragments and boulders, it is a challenge to decide where to collect samples ... Later, NASA also comprehensively analyzed the future role and some economic significance of asteroids, and finally set up a special budget to support the Osiris-Rex asteroid detector.
On February 3, last year, at 2: 43 pm on Kloc-0, 65438, the Osiris-Rex asteroid probe circled the 500-meter asteroid Benoit, and the engine burned for 8 seconds. The $800 million OSIRIS-Rex mission, whose name stands for "Origin, Spectral Interpretation, Resource Identification and Security", aims to help researchers better understand the early solar system and reveal the role of C-type carbon asteroids like Benoit in the origin of life on Earth.
Now, most of the information of scientists comes from the analysis of the original data of the OSIRIS-Rex asteroid detector. In the future, the OSIRIS-Rex asteroid detector will dive in mid-2020, grab a large number of asteroid soil and gravel samples, and the samples will land in the Utah desert in September 2023.
OSIRIS-Rex asteroid detector will also make outstanding contributions in other aspects. For example, this mission will improve scientists' understanding of the threat level of Benoit-like asteroids (500 meters), help researchers fine-tune the rules of potentially dangerous space rocks, and draw the trajectory of the asteroid Benoit. The mission of the OSIRIS-Rex asteroid detector is still in progress, and it will bring samples back to Earth in the future. Let's look forward to it. What OSIRIS-Rex needs to do next is to land and get samples.
Speaking of asteroid exploration, I have to say that Japan's Hayabusa-2 Hayabusa-2 mission is an ambitious plan of Japanese asteroid exploration mission. Its basic goal is to fly to the nearby asteroid Dragon Palace, that is, Ryugu, and then collect samples on the ground, then use a space gun to launch metal to hit the surface, collect samples in the crater, and finally send the samples back to Earth.
Earlier this year, the spacecraft just completed the fourth step. While conducting scientific research, it landed and took some amazing photos. The samples collected by Hayabusa II this time are different from those collected by Osiris Rex and Rosetta mentioned earlier. Previous samples were collected from the surface of asteroids, and the situation was basically the same for many years. But Hayabusa II has a space launch system with several copper bullets in it, which are launched by thrusters at a speed of 2000 meters per second. It formed a crater, so that samples inside the asteroid could be collected. Therefore, it can be said that Hayabusa II is the first spacecraft to sample the interior of an asteroid.
In July this year 1 1, the spacecraft landed on the asteroid Ryugu for the second time. This time, the detector hit the surface of Ryugu with an impactor and found some samples from the crater.
Underground sampling operation is a complex task. Hayabusa II must first find a good place for the sampling point. Once it chooses the sampling position, it will start its small impactor SCI.
Before launching the copper bomb, Hayabusa II needs to leave a camera before the impact point. This camera is called DCAM 3, and its task is to observe and draw the impact point. Then, Hayabusa II made a two-week journey at a distance of Ryugu 100 km to protect itself from impact.
The scientific phase of Hayabusa II will end in 20 19 12. At that time, the sample will be packed in a protective tank, and the spacecraft will ignite its ion engine and return to Earth. When it approaches the earth, it will send a sample to the earth and return to the tank SRC, and the parachute will slow it down and land on the ground. There, it will be collected.
According to JAXA, these samples will be sent to Earth in June 5438+February 2020. These samples will be sent to the off-ground sample collection center of Japan Aerospace Exploration Agency, and scientists can request some samples for research.
It can be seen here that our technology of detecting asteroids is gradually deepening from simplicity, and the methods of detecting asteroids in the future will be more diverse. There will be many kinds of institutions facing asteroids in the future. One is scientific institutions, and scientists will be responsible for studying and exploring the deep value of asteroids. Another kind of organization is a commercial organization. Some people who are optimistic about the future of asteroids will develop their own space mining machines and so on to gain benefits.
However, whatever it is, it is good news for mankind. In the future, space will become more and more lively, symbolizing the great progress of human science and technology.