This article is from the official account:Planet Office (ID: haibaraemily_planets), author: haibaraemily, Publisher:Popular Science China, Producer: Computer Network Information Center, Chinese Academy of Sciences, title picture from: Visual China

On July 30, 2020, NASA’s Perseverance Mars rover took off from Cape Canaveral Air Force Base in Florida on board the Space God V-541 rocket. [1]. Following the UAE’s Hope and China’s Tianwen-1, the last player of this Mars season went to Mars.

The Space God V-541 rocket equipped with Perseverance ignited into space. Source: NASA

From all angles, Perseverance is full of the shadow of its predecessor Curiosity, whether it is the shape, landing method, detection target, scientific instrument, all show the temperament of Curiosity Pro. And Curiosity, as a super star that has been on Mars for nearly 8 years, its successor naturally gave us a lot of indescribable intimacy, like an old friend who has known for a long time, showing humanity’s exploration of Mars. How is it passed down.

Curiosity vs Perseverance, eight years have passed. Source: NASA/JPL-Caltech

The goal of Perseverance is to continue to exploreFind out the geological and climatic environment of Mars and look for traces of microbes in the past on Mars (see: How far are we from life on Mars?). Compared with Curiosity, what black technology has Perseverance upgraded and replaced?

Fighting against the wind

The most shining star of Perseverance on this trip may be the small drone Wit it carries.

The Wit UAV installed at the bottom of the Perseverance. Source: NASA/JPL-Caltech

So far, humans have four ways to detect other planets: fly by, orbit, land, and patrol. (In fact, there are accompanying flying, but considering that they are generally small flying celestial bodies, and small celestial bodies rotate very fast, so rounding is almost the same as flying around.)< /span>

flyby, orbiting, landing, roving. Adapted from: CGTN [2]

And Perseverance will try to bring a new detection method for mankind: drone detection. You must know that let alone Mars, human beings have not flown a drone on any other planet besides the earth. This is the first time.

How exciting is the use of drones to explore other planets? In the absence of a real test flight on Mars, another drone mission, NASA’s Dragonfly, has been selected for the Xinjiang boundary-class mission in the Nether, and is scheduled to go to Titan in 2026.

‍The imaginary picture of the Dragonfly drone working on Titan. Source: NASA‍‍

But unlike Titan, which has a dense atmosphere, or the Earth, which has a general atmosphere, the atmosphere of Mars is too thin. The atmospheric pressure on the surface of Mars is only 0.6% of that of the earth.It is much more difficult to “fly” with drones on the planet.

The response method of the wit is also very straightforward: it is as light and small as possible, the blades are as large as possible, and the speed is as fast as possible. The entire witty weighs only 1.8 kg, and the total length of the blades is 1.2 meters, and the speed is up to 2400 rpm.[3, 4]< /span>.

Strictly speaking, this is a coaxial anti-propeller helicopter

As a testing machine, the Gizwits does not carry any scientific instruments(cameras are divided into scientific cameras and engineering cameras), and the working hours are not long: It can only fly with full blood for about 90 seconds on a full day of charging, and fly 300 meters away(not a lot, Curiosity can walk 3 kilometers in a year). But it needs to verify many technologies such as heat preservation, charging, autonomous flight, and photography on a distant planet. If the test goes well, it can even detect terrain and plan routes for Perseverance. Wit plans to fly 1 to 4 times.

Gizwit UAV flight operation diagram. Source: NASA/JPL-Caltech [5]

If Wiz can successfully complete the test, it will mean that the way humans explore other planets has been expanded again: probes will not only be able to patrol and gallop on solid planets, but also on planets with atmospheres like Mars. Go up against the wind and use drones to expand our detection horizons.

Work Imagination with Wit. Source: NASA/JPL-Caltech

Life “Detective”

In order to search for traces of life on Mars, Curiosity’s greatest magic weapon is a powerful organic detection device in its belly, called the Mars Sample Analyzer(Sample Analysis at Mars), referred to as SAM(Sam). The solid samples of Mars collected by the robotic arms will be sent to the “Sam”, where they are subjected to pyrolysis to detect whether there are complex organic matter in them. “Sam” is the largest and most complex instrument on the Curiosity rover. It is also the help of “Sam” that allows Curiosity to discover a variety of thiophenes on Mars.(C4H4S), aromatic and aliphatic complex organic matter (see:).

Mars Sample Analyzer SAM and its internal instruments. Source: NASA

The Perseverance used a set of remote analytical instruments to detect organic molecules and possible traces of life-named after the detective “Sherlock Holmes”, this instrument is called Sherlock (full name “Raman and fluorescence scanning livable environment, searching for organic and chemical substances”, abbreviation SHERLOC). Sherlock is installed on the front end of Perseverance’s robotic arm, including an ultraviolet laser Raman spectrometer and a camera nicknamed “Watson”, which can work together to finely detect the mineral composition, organic molecules and possible traces of life on the surface of Mars[6].

Source: NASA/JPL-Caltech

The instrument calibration board of “Sherlock” is also worth mentioning. Many instruments sent to Mars need calibration objects brought from the earth. At the same time, the gradual changes of these calibration objects under the extreme temperature and radiation environment of Mars can also help us understand the impact of the Martian environment.

Feel the size of Sherlock’s calibration board. Source: NASA/JSC [7]

Sherlock carried 10 calibration objects, the most topical of which was a slice of the Martian meteorite Sayh al Uhaymir 008. This meteorite from Mars was found by humans in the Oman Desert in 1999, and this time, Perseverance will send it home.

A slice of the Martian meteorite Sayh al Uhaymir 008. But not only Sherlock, the Perseverance super camera also carried oneMartian meteorites are used for calibration, but that one is much more low-key. Source: NASA/JPL-Caltech/PIA22245

In addition to Martian meteorites, Sherlock’s calibration board also contains five spacesuit fibers and helmet materials. How these materials perform in the Martian environment and how they will age are related to future astronauts when they board Mars. safety. This is the first time humans have sent spacesuit materials to Mars [6].

Thank you Weibo netizens for helping Chinese translation, these materials are all in Chinese, and I have fallen into the blind spot of knowledge Chinese translation: NASA/PIA24033

If you look closely at Sherlock’s calibration board, you can find the (polycarbonate material) in the lower left corner says “Baker 221 Street”, it’s the rhythm of secretly carrying the cue stalk to the end. From now on, Perseverance will be “221 Baker Street” on Mars.

Sherlock’s calibration board. Source: NASA/JPL/collectSPACE [8]

Oxygen production from Mars

The sample analyzer “Sam” (SAM) of Curiosity was removed, and the “belly” of Perseverance gave another unprecedented instrument Free up a bit of space-Mars Oxygen In-Situ Resource Utilization Experiment (MOXIE) (Mars Oxygen In-Situ Resource Utilization Experiment, MOXIE).

(Left) Moxie’s location and parameters. (Right) The real thing is this golden box! Source: NASA/JPL-Caltech

Moxie collects carbon dioxide from the Martian atmosphere, electrolyzes it into oxygen and carbon monoxide. After purifying the oxygen, the carbon monoxide and other products are discharged back into the atmosphere.

The principle of Moxibustion oxygen production. Simplified production based on NASA data

Martian atmosphere approximately96% of the composition is carbon dioxide, and humans who will land on Mars for exploration or even long-term living will need more oxygen for survival. If the carbon dioxide of Mars can be directly used to produce oxygen, then humans in the future will not have to travel all the way from the earth to bring liquid oxygen to Mars, but can directly produce oxygen on Mars for daily breathing and propellant use. Thinking about it is an exciting thing!

Make the life support system in “The Martian” possible. Source: Movie “The Martian”

The acronym Moxie also has a different meaning. MOIXE means “courage, boldness, tenacity, and adventurous spirit.” This is also NASA’s expectations for this exploratory instrument.

NASA also cueed a soda drink brand called MOXIE by the way, which was acquired by Coca-Cola in 2018. Source: Wiki

strong “arm”

Compared to Curiosity, Perseverance’s biggest adjustment in appearance is to put more of its focus on the robotic arm. It can be said that Perseverance will be the strongest “one-armed hero” in the current rover.

The robot arm of the Perseverance. Source: NASA/JPL-Caltech

In addition to the drill and camera that Curiosity has, Perseverance also installed two of its seven major instruments on the front of the robotic arm: one is the life detective “Sherlock” mentioned in the previous section, and the other It is an X-ray fluorescence spectrometer (The Planetary Instrument for X-ray Lithochemistry, abbreviated PIXL) that can detect the ultra-fine chemical composition of rocks.

Another meaning of PIXL is the homophony of “pixel” (pixel), which is used to express how this instrument will “see the details”. It can not only detect the ingredients contained in the rock, but also restore the pixel-level resolution to clearly capture the arrangement of these ingredients.

(Left) PIXL sensor probe; (Right) PIXL has advantages over other instruments that detect elements (such as the APXS carried by Curiosity). Source: NASA/NICOLAS MICHEL-HART, UNIVERSITY OF WASHINGTON

The combination of PIXL and Sherlock’s double swords can help us detect more reliable suspected microorganisms on Marsremains.

Did you dizzy? Two steps without dizziness? Come and come and strike again. Take one of the oldest biological fossils on earth-stromatolites as an example. PIXL can detect which elements and the microscopic arrangement of the elements are contained in this stone, and Sherlock can detect what is in this stone. Which minerals and organic molecules are contained. Source: References [9]

In addition, Perseverance has also upgraded its drill bits: The Curiosity drill bit can only collect Martian rock and soil powder, while the Perseverance drill bit can directly collect the complete core, which will help future human analysis “Non-destructive” Martian rock samples. This will also be the first time humans have collected a core sample of Mars.

(Left) Schematic diagram of Yilihao sampling; (right) Schematic diagram of core drilling. Source: NASA, References [10]

Sampling returns to pioneers

In the “Sam”, the predecessor Curiosity’s instrument for detecting life on Mars, there is a complete set of “test tube sets” like a double-layer carousel. These “test tubes” are the chemical experiment cups for Curiosity to analyze samples.

The Perseverance still carries a set of “test tubes”, but these “test tubes” are only used to encapsulate the Martian samples collected by the drill.

Yilihao’s sample collection tube. Source: NASA, References [9]

Yes, Perseverance completely abandoned Curiosity and even Viking’s model of direct collection and contact analysis of samples through robotic arms, and was only responsible for sample collection and packaging:

Perseverance Drill The sampling and packaging process is shown. Source: NASA/JPL-Caltech

After that, Perseverance will transfer the sample tube to the designated location:

The second station is the sample cache station. If there are further expansion tasks (the dotted line), the samples collected by the expansion task will be returned and sent back Cache station. Source: NASA

Reserved for future Mars missions to pick up and return to Earth, for humans to personally study:

Indicating the return mission of Mars sampling. Source: NASA/JPL-Caltech

Embrace the future

As a player holding all eight successful Mars landing missions, NASA has undoubtedly the most experience in Mars exploration and is also at the forefront. With the experience of the predecessors and the strongest capital investment, the Perseverance Mars rover worth US$2.4 billion obviously still has too many details worth digging and learning. This is not something that can be covered in one or two articles. There is a chance. Let’s talk about it again.

For example, Perseverance combines Curiosity’s original mast camera (Mastcam) and chemical camera (ChemCam) upgraded to a zoomable mast camera (Mastcam-Z) and a super camera that can analyze minerals and molecules and take color photos Camera (SuperCam).

The 7 major instruments of Perseverance. Source: NASA/JPL-Caltech

Perseverance and my country’s Tianwen-1 rover carry subsurface radars. Two ground surveying radars will deeply detect the shallow underground structure and water ice distribution along the rover. Mars, who has never seen the patrol geodetic radar, will welcome two in one breath.

Schematic diagram of the subsurface radar (RIMFAX) of Perseverance. Source: NASA/JPL-Caltech

The Perseverance carries more cameras, 23 at all, with “eyes” all over her body.

The camera distribution of Perseverance. Source: NASA/JPL-Caltech [11]

Perseverance updated its software system on the basis of Curiosity and designed more durable wheels.

Curiosity vs Perseverance Wheels. Source: NASA/JPL-Caltech

But in general, Perseverance obviously has a bigger goal and a more pioneering goal than upgrading equipment and exploring more scientific puzzles-not obsessed with using limited resources to get everything. There may be as many scientific achievements, regardless of the momentary gains and losses, but really focus on the future. Whether it is the Witt UAV or the Moxie Oxygen Concentrator, it is the “test mission” of this Perseverance. Their biggest goal is to verify the feasibility of the technology for future manned Mars missions. paving. Collecting rock cores and encapsulating samples of Mars leaves more “discovery” opportunities to the future, perhaps ten years later.

7 months later

Perseverance’s Mars journey is planned to spend about 6 and a half months on the road, with 5 to 7 orbit corrections on the way.

The Perseverance Project Track. Knock on the blackboard to review, this is the fast transfer track discussed in the previous issue. Source: NASA/JPL-Caltech

If all goes well, the Perseverance rover will hit Jezero on the surface of Mars on February 18, 2021. (Jezero) pit.

This is the remains of an ancient lake, with delta and flowing water landforms, rich volcanic lava products and mineral deposits. It is an environment carefully selected by planetary scientists that may breed and preserve life traces. The nuclear battery plus Perseverance has a design life of 1 Martian year(about 2 Earth years), of course, according to our previous NASA rover From experience, it will actually work longer if nothing happens.

The rich sediments in the delta of the Jezero impact crater: green is clay minerals, yellow is olivine and carbonAcid salt. Overlay of MRO CTX image and CRISM spectral image. NASA/JPL/JHUAPL/MSSS/Brown University

Even if we don’t talk about this, just 7 months later, the sky crane black technology will be reappeared over Mars, which must have already excited many friends.

The aerial crane/ aerial crane landing was once a unique landing method for Curiosity, and Perseverance will also be used. © NASA/JPL

What’s more-there is also NASA’s traditional performance of “Take your name to Mars”! By then, there will be another 10.93 million names of people on Earth packed in small chips that will be on the surface of Mars with Perseverance[12 ].

The names are all here. Source: NASA/JPL-Caltech

However, in addition to these, Perseverance also installed an 8×13 cm aluminum plate on the left side of the Mars rover chassis. The picture shows the Asclepius rod, which represents medicine, lifting the earth, and on it is the exploration The aircraft flew out of the earth and went to more distant planets. This aluminum plate is intended to pay tribute and thank medical workers all over the world during the new crown epidemicHis great dedication, it is because they are guarding the earth that mankind can continue to explore more distant places.

(Left) Commemorative aluminum plaque carried by Perseverance; (Right) Asclepius’ rod representing medicine, which is also a World Health Organization Elements in the logo. Source: NASA/JPL-Caltech/WHO

See where this aluminum plate is?

Thank you to medical workers all over the world. Source: NASA/JPL-Caltech/WHO

So far, the three players of this Mars season (UAE Hope, China Tianwen-1, NASA Perseverance) have all submitted their papers. Go smoothly to Mars. In February next year, the “Mars Test” of the three countries will usher in their first round of “acceptance of results”, let us look forward to it together.