Pengpai News reporter Nan Boyi Intern Ji Wenlei
[Editor's Note]
July 23, China's "Tianwen-1" Mars rover successfully entered orbit and began to rush to Mars.
This year is a big year for Mars exploration. The UAE, China and the United States will launch probes to Mars one after another. As the planet close to Earth and with the most similar environment, Mars has always been a hot spot for human deep space exploration, especially after the end of the Cold War, Mars exploration is no longer the patent of the United States and the Soviet Union, and more and more countries have joined this ranks. Next, The Paper (www.thepaper.cn) launches a series of articles to present the current situation and future of Mars exploration in various countries.
Europeans had a strong interest in the red planet Mars for a long time. The ancient Greeks named this red planet the god of war more than 2,000 years ago; Kepler calculated the orbit of Mars in 1609; and astronomer Antoniadi observed a "canal" on Mars in the early 20th century.
For a long time, Europeans have made many very interesting observations and imaginations of Mars with their naked eyes and telescopes. Even in the 1897 novel "World War", British writer H.G. Wales vividly depicts the appearance and physiological structure of life on Martian.
On June 2, 2003, the " Mars Express " launched by the European Space Agency (ESA) once again ignited Europeans' curiosity about Mars.
Europe's ExoMars Mars exploration mission also includes orbiter , lander and cruiser.
The super long "Mars Express"
"Mars Express" contains two parts: the "Mars Express" orbital probe and the "Beagle 2" lander. Although the good friends successfully arrived at Mars after a six-month journey, their respective endings were very different: "Mars Express" successfully entered the orbit of Mars on December 25, 2003, and then successfully entered the polar orbit around January of the following year (which means that the Express can cover the entire range of Mars); and "Beagle 2" lost contact with the earth after landing at the scheduled landing point due to the inability to deploy wireless communication antennas. Since then, the "Mars Express" has become the only hope for Europeans.
The "Mars Express" that lost its partner did not disappoint. It soon gave humans a big gift: On January 23, 2004, the ESA announced that scientists confirmed that the existence of water ice in the South Pole crown of Mars by analyzing the spectral data collected by the "Mars Express".
This is the first time that water molecules have been discovered on the surface of Mars. Before this, scientists mostly stayed at the indirect inference level of view. For example, some experts analyzed that some surface landscapes on Mars are very similar to those on the Earth, and they may be eroded by the impact of water flow; in addition, in 2002, the US "Odyssey" probe discovered hydrogen atoms on Mars, and some experts also believed that these hydrogen atoms may come from water. The Mars Express directly used an infrared detector (OMEGA) to detect water molecules present in Antarctic frozen soil. This discovery undoubtedly opened up people's imagination: when humans move to Mars in the future, they are likely to use local materials and directly collect and utilize existing water resources on the Red Planet.
"Mars Express" major discovery about water is more than that. In July 2018, Italian scientists used the Mars Express's "underground and ionospheric detection radar instrument (MARSIS)" to discover the first liquid lake located under the ice sheet of Mars' Antarctic, with a span of about 20 kilometers. This is the first known stable water on Mars. From this, scientists speculate that there is a possibility of life below the surface of Mars. But the question is, the annual average temperature in the Antarctic region of Mars is minus 60 degrees Celsius, so why are the lakes under the ice cap not frozen? Scientists explain that this lake may have lowered the freezing point of water due to the presence of a large amount of salt.
"Mars Express" has achieved many exploration results
In addition to water, "Mars Express" also discovered that the existence of methane on Mars. On March 30, 2004, "Mars Express" ushered in another highlight moment: the ESA announced that "Mars Express" discovered methane in the Mars atmosphere. This news was like a bombshell that sparked heated discussions in the astronomy community.
Why is methane? What is special about it? As the simplest organic substance, most of the methane in the earth's atmosphere is released by various living substances, such as the gas excreted by cattle when they digest food. Therefore, the discovery of methane on Mars led scientists to speculate that there may be some kind of "cow" on this planet. What’s special about methane is that its volatility time is particularly short, but according to the data available now, methane has existed on Mars for at least 300 years. So what kind of substances continue to release methane in these 300 years? Perhaps Mars not only has life, but also has a large number for a period of time.
If "Mars Express" is compared to a student, then the student will not only have good academic performance, but also be particularly diligent and helpful. The reason for being diligent is that according to the plan of the European Space Agency , the "Mars Express" can be retired in December 2005 after orbiting Mars for a year (687 Earth Days). However, as the "only hope for the whole village", ESA has extended its lifespan and tasks to 2026 through a single operation, and has served for nearly 20 years after exceeding the deadline. It is said that it is helpful because the "Mars Express" has helped many other countries to explore Mars equipment over the years. For example, in 2008, the Mars Express tracked the landing process of the Phoenix probe in the United States in real time, providing scientists on Earth with a large amount of login data. In 2012, through mapping the Mars surface observations, the Mars Express helped the US Curiosity rover determine its final landing point.
It can be said that the "Mars Express" that has served for many years has made great contributions to the human Mars exploration cause. It not only proves people's previous inferences about Mars, but also opens up new topics for analysis and research by later generations (such as later trace gas orbiters). It can be said that the "Mars Express" played a role in connecting the past and the future in Mars exploration activities in the early 21st century.
Like the Beagle 2 lander, the Schiaparelli lander failed to land on Mars smoothly.
The twists and turns ExoMars
Although the Mars Express has achieved many exploration results, it will not satisfy ESA, not to mention that the previous "Beagle 2" mission to land on Mars is difficult to say. Against this background, the "ExoMars" mission, which was born in the 2001 "Goddess of Dawn" project, began to surface.
In March this year, the ESA and the Russian Space Agency announced that the original plan to launch ExoMars to postpone in July this year, the sixth postponed for the mission, and its earliest planned launch in 2009. As for Mars exploration, there is a "family barrel" model that major countries are very pursuing, that is, a complete Mars exploration plan must include three parts: orbital probe, lander and rover. ExoMars initially included only two projects: Lander and Mars rover. ESA plans to undertake the ExoMars mission in 2011 by the Russian "League" Rockets. From a planning and design perspective, this is also similar to the design of the Mars Exploration Rover mission at that time.
By 2006, the ExoMars mission was changed to add a "cost-effective" orbital probe, which can not only perform exploration missions in Mars orbit, but also serve as a platform for relay communications. Because the lifespan of several orbital detectors that have been in service for many years, including the "Mars Express" cannot be guaranteed, launching new detectors has become a requirement for the situation.
But the problem is: the total weight of the three projects has increased greatly after the merger of the three projects, which has exceeded the carrying capacity of the original "League" Rockets, and other rockets that can meet their carrying needs are very expensive (for example, the price of the "Arian 5" Rockets in Europe is twice that of the "League" Rockets). Afterwards, the ESA turned its attention to Russia. In June 2007, the ESA proposed to provide assistance to Russia's Phobos mission in exchange for the same price of the Proton rocket, but Russia rejected the proposal and had to postpone the mission.
Russian-made Cossack lander
In 2009, NASA extended a helping hand, and the ESA signed the Joint Mars Exploration Initiative (MEJI) with it, planning to use two "Cosmic God" 5 rockets to undertake launch missions in batches. At the same time, Russia's previous attitude of rejecting the ESA has also begun to become active, and after negotiation, it has determined to use the Proton as a backup rocket for launching the rover. In return, Exomers rover will be equipped with Russian instruments, and ESA will also provide support for Russia's Forbes-Soil mission.
html There were unexpected events in 0 days. By 2012, due to budget overspending, NASA unilaterally withdrew from the joint Mars exploration initiative, and the plan to use the "God of the Universe" 5 rocket ended in vain. In this case, the backup plan begins to appear. The Proton rocket eventually officially became the ExoMars launch vehicle. At this time, Russia also happened to need the ESA because the Forbes-Soil detector failed to launch. Under such circumstances, ESA and Russian Aerospace reached a cooperation again in 2013: First, Russia provides two "Proton-M" rockets and all launch services; second, it carries two Russian instruments that were originally equipped with the "Forbes-Soil" on the trace gas orbiter TGO; third, it shares all scientific data.According to the European-Russian agreement, the ExoMars mission will use the "Proton-M" rocket to transport Mars exploration equipment in two phases: the first phase is also called ExoMars 2016, and the ESA launches the "Trace Gas Orbiter" (TGO) and the experimental "Schiaparelli" EDM lander. The second stage is also called ExoMars2018. ESA's Rosalind Franklin and Russia's Kazachok are scheduled to launch in 2018. The detectors of the
ExoMars mission were launched by Russian "Proton" rockets
History is always surprisingly similar. ESA's "Trace Gas Orbiter" (TGO) arrived on Mars in 2016 and began scanning the Martian atmosphere in 2018 for methane. It carries a sieve and bottom point spectrometer (NOMAD) and atmospheric chemical spectrometry measurement combiner (ACS) to monitor low concentrations of methane. TGO weighs 3.7 tons and is launched by the Russian Proton rocket. When it works in Mars orbit, the spectrometer can observe the Martian surface and draw a map of methane hotspots on the Martian surface; in addition, it can also obtain detailed information on methane content at different altitudes. TGO carries the 600kg lander, Schiaparelli, which is regarded as the successor of the Beagle 2. The lander plans to land on the meridian plateau near the Martian equator. After landing, it will rely on batteries to work on the Martian surface for several days, but unfortunately, the Schiaparelli lost its signal before landing.
and the second phase of ExoMars is also not going well. In May 2016, ESA announced that it would postpone ExoMars 2018 for two years due to equipment and instrument manufacturing issues, and ExoMars' second phase was renamed ExoMars 2020. On March 12, 2020, the ESA and the Russian Aerospace Administration once again decided to postpone the launch plan to 2022, and ExoMars2020 once again became ExoMars2022. Considering the "tradition" of constant delays, it is also a big question whether ExoMars can really launch on time in 2022.
Generally speaking, looking back at the ESA's Mars exploration mission over the years, although it has achieved fruitful results, it is also "unlucky". However, looking back at history, isn’t every human space adventure mixed with “scars” in its “glory”?
Editor in charge: Xie Ruiqiang
Proofreading: Yu Chengjun
