Sept. 7 is an unpleasant day for Indian space flight. At about 2:15 a.m. local time on the 7th (4:45 a.m. Beijing time on the 7th), the Indian Space Research Organization (IRSO) announced that the Indian Lunar Ship 2 lander lost its signal when it was 2.1 kilometers from the lunar surface. This means that Indias first lunar soft landing mission ended in failure.
When the lunar soft landing mission failed, there was encouragement, regret, teasing and irony on the Internet. Then, how to treat Indias Lunar Exploration Mission Lunar Ship 2 as objectively as possible, the author talks about his own point of view, throwing a brick to attract jade.
Vikram Lander on Moonship 2
Great Rocket Progress
The Lunar Ship 2 spacecraft, weighing 3.85 tons, is the largest self-launched spacecraft in India. It uses the GSLV-MK3 rocket developed by India. This is the third launch and the first practical operational launch of the GSLV-MK3 rocket. Whatever the success of the Lunar Ship 2 probe, its successful launch into space alone shows that India has made a big step forward in space development.
The GSLV-MK3 rocket is Indias most capable rocket at present.
Indias original GSLV-MK2 rocket has a synchronous transfer orbit capacity of only over 2 tons, which results in many large satellites launching by foreign rockets. Lunar exploration, as a project to boost public morale and highlight national honor, is obviously not suitable for launching by foreign rockets. Fortunately, the GSLV-MK3 rocket completed its development test in time and caught up with it. Launch of Lunar Ship 2.
The GSLV-MK3 rocket consists of two S-200 large solid boosters, plus L110 core stage I and L25 core stage II. S-200 indicates that the solid booster charge is about 200 tons, L110 indicates that it contains about 110 tons of liquid propellant, L25 is about 25 tons of liquid propellant, but the core stage L110 is not the same: the core stage L110 is partial dimethyl. Hydrazine and nitrogen tetroxide at room temperature propellant, while core secondary L25 is liquid oxygen liquid hydrogen propellant. The launch weight of the GSLV-MK3 rocket is 640 tons, and it has the ability to deliver 8 tons of load to 600 km high near-earth orbit or 4 tons of synchronous transfer orbit. Its appearance almost doubles the carrying capacity of the Indian rocket. The L110 core stage is the first liquid engine parallel design in the Indian rocket, and the L25 core stage is self-developed by India. The 20-ton CE-20 liquid oxygen and liquid hydrogen engine made in India is a major advance in space technology.
The GSLV-MK3 rocket has been successful in both half-rocket test flights at the end of 2014 and two test launches in 2017 and 2018. The Lunar Ship 2 spacecraft was originally scheduled to launch on July 15, but the leak of helium supercharger system occurred in the low-temperature hydrogen and oxygen stage of the rocket L25 before takeoff. The Indian astronauts solved the problem within a week and successfully launched it on the 22nd. From this point of view, the progress of Indian space in the comprehensive level of rockets is still very obvious.
Yuehuai 2 in rocket fairing
Detectors are of high quality and low cost
The Lunar Ship 2 has its own advantages. ISRO says the mission cost only 9.78 billion rupees ($142 million). Whats more shocking is that the Lunar Ship 2 probe itself spent only 87 million dollars. You know, the Lunar Ship 2 probe is very complicated. It consists of a 2,379 kg orbiter, a 1,471 kg lander named Vikram and a 27 kg lunar rover named Pragyan. Each of the three parts carries different detection loads, and the lander is large. Quantity sensors are used for soft landing on the moon, which once again reflects Indias space style of doing big things with little money.
The Lunar Vessel 2 probe includes an orbiter, a Vikram lander and a Lunar Vehicle Wisdom.
Lets first look at the orbiter of Lunar Ship 2, which is responsible for the orbit change from Earth orbit to lunar orbit, and is the head of the probe in terms of weight. Lunar Ship 2 is a soft landing mission, the most concerned is Vikram lander and Wisdom lunar rover, and its orbiter design is also remarkable: its design life of one year, will use topographic mapping camera (TMC-2) to generate three-dimensional images of the moon again; it also carries SAR radar, the last Lunar Ship 1 It also brought infrared imaging spectrometer and soft X-ray spectrometer to detect the material composition and distribution on the surface of the moon. What is most expected is that the orbiter has a high resolution. Cameras, known as 0.32 meters resolution, to know that the United States LRO detector is only 0.5 meters resolution, Indian lunar camera to make a world first, if the United States Apollo lunar module or Chinas Change 3/4 to take photos, these probes may have many new photos.
The scientific instruments of the Vikram lander have few bright spots, but the sensors that guarantee the soft landing still have some bright spots. In order to ensure the soft landing, it is equipped with position detection camera, horizontal velocity camera, Ka-band radar altimeter, laser altimeter and obstacle avoidance camera, which can be said to be the eighteen weapons sample of lunar landing technology. From the Moon series of the Soviet Union to the Apollo of the United States to the Change series of landers in China, there are not as many landing sensors installed as in India. The orbiter is equipped with Alpha Particle X-ray Spectrometer (APXS) and Laser Induced Breakdown Spectrometer (LIBS), which are used to analyze the composition and abundance of the lunar surface. Indias Lunar Ship 2 probe spends so much money, but it can use so many new equipment, which is also a reflection of Indias advantage after space flight.
Lunar soft landing is not easy
On the morning of September 7, the Vikram lander carried out power descent and lunar soft landing. It was equipped with five 800 bull main engines and eight 50 bull attitude control engines. At the beginning of the descent, four 800 bull engines on the outside were fully powered on, two 800 bull engines on the hovering stage and one 800 bull engine in the center on the landing moon. Indias reluctantly changing thrust engine is also a recipe for failure of the India lander.
The Indian Space Research Organization (ISRO) broadcast live the lunar landing challenge of the Vikram lander. With so many sensors, the lander went down fairly smoothly in the early stages, but suddenly lost contact at an altitude of 2.1 kilometers. According to the flight trajectory shown on the live Indian video, the lander then deviated from the intended design and accelerated. Its obviously very abnormal. Combining all the information, it is likely that there is a problem in the attitude during landing and descent. When the engine works downward but the attitude becomes unstable, it loses the signal and the control program shuts down urgently to prevent the lander from accelerating and descending. Although the lander will automatically adjust later, it will not be high enough to complete the normal lunar landing and eventually fall on the surface of the moon.
Specifically, there may be two reasons for the failure of lander soft landing: one is that the hardware of inertial navigation system is out of order and the attitude information is out of order; the other is that the algorithm of soft landing control is out of order, which leads to the abnormal attitude and the failure of landing on the moon. This year, Israels Genesis failed to land on the moon due to inertial navigation hardware problems. The failure of India and Israel to land on the moon shows that the technology of soft landing on the lunar surface is still very difficult. The side also reflects that Chinas Change 3/4 successfully landed on the moon is very rare.
Aerospace is a high-risk undertaking, and failure is inevitable. To find out the reasons and overcome them after failure is also the stepping stone of human beingscontinuous success in the vast universe.
Although Indias Lunar Ship 2 lander failed in soft landing, its orbiter will still complete many exploration missions in orbit, which can improve Indias understanding of the moon. Formal launch of manned space program, launching probes to Mars, exploring the moon... I have to admit that todays Indian space is no longer the Wuxia Amon of the past.
Source: Peng Mei News Responsible Editor: Li Zaixing_NBJS9026