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Останнє оновлення:
24.02.2017


Case-lesson «Course to Mars!»
Case-lesson «Course to Mars!»

Category: Science, nature and man

The level (grade): 11

Subject: Physics, chemistry, cosmology.

Objective: Learn the capabilities of astronomy and astronautics to solve problems of present and future.

What information is waiting for me here?

  • What is Mars from the point of astronomy view?
  • The climate and geology of Mars.
  • Mars exploration: history, present and future.
  • Is there life on Mars?
  • Colonization of Mars: is it possible?
10 scans of the subjects, phenomena and practices:
Introduction

The planet Mars is a popular topic for the human imagination and curiosity: the scientists conduct researches, the writers write stories and novels, the producers make movies. Periodically Mars appears in the press: "Humanity has reached Mars!", "Water has been found on Mars!", "There are new unique images of the Martian canals!".

 

The priests of Babylon held a primitive observation of this planet; modern scientists are developing ambitious programs of exploration and colonization.

We will watch this development of human thought to find the answer to the question: whether Mars is the future of the Solar system.

Astronomy

Mars is the fourth planet from the Sun and the seventh planet in size of the Solar system.

Mars is a planet of the terrestrial group with a tenuous atmosphere (surface pressure is 160 times smaller than the pressure of Earth). The surface terrain of Mars can be considered as impact craters, (like on the Moon), volcanoes, valleys, deserts and polar ice caps (like on the Earth).

Mars has two satellites: Phobos and Deimos (from the Greek "fear" and "horror"). They are relatively small (Phobos is 26.8×22,4×18.4 km, Deimos — 15×12.2×10.4 km) and have irregular shape.

 

The topography of Mars has many unique features. The Martian volcano Olympus is the highest mountain in the Solar system. Valley Mariner is a giant system of canyons on Mars, the largest in the Solar system. It was discovered in 1971-1972 by the spacecraft "Mariner-9".

The largest impact crater in the Solar system is on Mars. Its length is 10.6 thousand km, and the width is 8.5 thousand km.

The mass of the planet is 6,418•1023 kg (11% of the Earth). The acceleration of gravity at the equator equal to 3,711 m/S2 (0,378 of the Earth).

According to the linear size, Mars is almost a half of the Earth. Its equatorial radius equal to 3396,9 km (53,2 % of the Earth). The surface area of Mars approximately equal to the land area of Earth.

Polar radius of Mars is approximately 20 km less than the equatorial, although the rotational period of the planet is larger than the period of Earth.

Mars and Earth (for size comparison)

The planet's period of rotation is 24 hours 37 minutes 22,7 seconds (relative to the stars), the average length of solar day is 24 hours 39 minutes 35,24409 seconds. This is only 2.7% longer than Earth days. The Martian year consists of 668,6 Martian solar days.

 

Mars rotates on its axis, inclined to the perpendicular orbital plane under an angle 25,19°. Axial of Mars tilt provides changing of the seasons. In this case, the elongation of the orbit leads to large differences in their duration.

Northern spring and summer consist of 371 days. At the same time, they fall on the plot of Mars orbit that is far from the Sun. So Northern summer is long and cool, while South is short and relatively warm on Mars.

The temperature on the planet ranges from -153 °C at the pole in winter to +20 °C at the equator at noon. The average temperature is -50 °C.

The atmosphere of Mars mostly consists of carbon dioxide and it is very sparse. The pressure at the surface of Mars 160 times smaller than the Earth. The pressure is always changed. The approximate thickness of the atmosphere is 110 km.

Question:


What is in common between the duration of the Martian and Earth's year?

Mathematics

How far is it to Mars? It is not a question of science fiction. This task can be solved with Math, because it is important to know the distance and time "in the way" for projects of colonization or of manned flight to Mars.

Theoretically, Earth and Mars are very close to each other under the following conditions:

1) Mars is in the point of Perihelion (the point of greatest proximity to the Sun).

2) The Earth is in the point of Aphelion (the point of orbit that is farthest from the Sun).

The minimum distance from Mars to Earth is 54.6 million km (when the Earth is exactly between the Sun and Mars). The maximum is about 401 million km (when the Sun is exactly between the Earth and Mars).

The distance between the Earth and Mars (during the confrontation 2014-2061.)

Let us consider the problem: how much time is needed for the sun's rays reflected from the surface of Mars to reach Earth?

The speed of light is 300.000 km/s. Let us use the universal formula, applicable to the most of the movement tasks:

 

Then the sun's rays reflected from the surface of Mars, reach earth at the time:

For maximum distance – 401.000.000/300.000 = 1337 with or 22 min.

For minimum distance – 54.600.000/300.00 = 182 with or 3 min.

The automatic interplanetary station "New Horizons" (NASA) is the fastest spacecraft that left Earth. The speed is about 58,000 km/h. How fast can it reach Mars? The calculation that can be applied to the sun's rays is not applicable to the space station. There are some reasons. The trajectory of the station will be different.

 

Many interplanetary missions are just not feasible without exotic methods of navigation. The velocity of the working body of chemical rocket engines is about 3 km/s. Thus every 3 km/s of additional acceleration can triple a launch mass of space systems. To go to Mars from the low Earth orbit (speed of 8 km/s), it is necessary to collect about 3.5 km/s, to Jupiter — 6 km/s, to Pluto — 8-9 km/s. It turns out that the payload in flight to distant planets is only a few percent of derived on orbit mass, and that, in turn, only a few percent of the rocket starting mass. Homan trajectory — elliptical orbit in celestial mechanics – is used to transfer between two orbits, that usually located in one plane. In the simplest case, it crosses two orbits. The orbital maneuver for moving includes 2-impulse engine acceleration. This trajectory was named in honor of German scientist Walter Homan:

 

The real way out of this situation – start from orbit. Why starting from orbit gives such great benefits? After all, several hundred or even thousands of kilometers from Earth to orbit are nothing compared to the distance to Mars. The fact is that the power of launched multistage rocket is uneven. The total energy of the spacecraft is usually measured by the sum of absolute values of all velocities that the rocket at various stages of flight has to develop. This amount is the characteristic of speed. Note that the velocity (and acceleration, respectively) is a vector quantity. Therefore, there are rules of addition of vectors in three-dimensional space are applied:

 

For the flight to Mars, the overall rate will be more than 30 km/s. Modern missile systems operate with chemical fuel. In the near future, the speed will not be above 15 km/s. Almost a half of the characteristic velocity is spent on reaching the orbital velocity (7.9 km/s plus losses). In addition, every kilometer of speed is the weight of fuel, the starting weight of rocket. At the stage of entering the orbit, a prevailing share of the initial weight of the rocket is realized.

 

Now it is understandable why to start from an orbit is more convenient: the weight of the ship is significantly smaller and the required characteristic velocity for the flight to Mars and back is less in two times than during the flight from the Earth. In addition, the use of several small missile ships is more real than building one big ship, weighing thousands of tons. This way will greatly facilitate the achievement of distant celestial bodies.

Homan trajectory is a special case of existence of Fibonacci fractals. They are a universal principle, applicable to the space and earth objects and phenomena:

Task:


The average distance between Earth and Mars is 227.800.000 km. Calculate the transit time of the reflected beam from the surface of Mars to the Earth.

Chemistry

Mars is called the red planet. Look at the night sky and you can distinguish Mars because of red color. However, when you look at photos taken on Mars, you will find that the planet is multicolored, not monochromatic. What makes Mars the red planet? The answer is in the field of chemistry, but not astronomy.

 

The surface of Mars contains a lot of dust and iron oxide. Dust of iron oxide is in the atmosphere of the red planet. It settles on the landscape.

For this reason, Mars looks like a rusty planet from outer space. The other colors just get lost in this dust. Red is the primary color, although some iron oxides can be brown, black and even green.

Why is in the atmosphere of Mars more iron oxide than in atmosphere of other planet? Scientists have not come to a definite conclusion. Nevertheless, many experts believe that this dust is the result of volcanic eruptions. Solar radiation causes atmospheric water to evaporate, and the steam reacts with the iron, oxidizing it and forming iron oxides.

Iron in the periodic table and an iron meteorite from the Martian surface

Iron oxidation can be described as follows:

 

Next redox reaction occurs in water. It is crucial for the formation of Martian "rust":

 

Iron oxides can also be a reaction product of iron meteorites. Under the influence of ultraviolet, solar radiation iron reacts with oxygen. The result is formation of iron oxides.

Question:


In what earth processes does the oxidation of iron occur?

Physics

It is difficult to find a physical law or phenomenon that is not involved in space technology. Especially in such demanding field as the exploration of Mars.

The first thing we remember talking about the planets from the point of view of physics – gravity.

 

The law of universal gravitation of Newton describes the gravitational pull. This law states: the gravitational attraction between two material points of mass m1 and m2 separated by distance r, is proportional to both masses and inversely proportional to the square of the distance:

 

Here is the gravitational constant equal to approximately

 

Gravity is a universal interaction between all material bodies.

In addition to the gravity, applied to the planets, we can also speak about the force of gravity.

The force of gravity is a force acting on any material body located near the surface of the astronomical body. The force of gravity on the planet surface consists of gravitational attraction and the centrifugal force of inertia (caused by the planet rotation around the axis).

The acceleration caused by the force of gravity is called the acceleration of free fall.

 

For Mars, like for other planets, the force of gravity can be calculated by the formula:

 

This is a variation of the formula that we have previously considered, but given the height of the body above the surface of Mars and the radius of Mars.

As it is known, the mass of the red planet in 9,31 times less than the mass of the Earth and the radius is 1.88 times less than the radius of the globe. Therefore, because of the action of the first factor, the gravity on the surface of Mars must be 9,31 times less, and because of the second – 3,53 times more (1,88 * 1,88 = 3,53). Ultimately it is little more than 1/3 part of the earth's gravity (3,53 : 9,31 = 0,38).

The study of cosmic bodies, including planets of the Solar system, requires the use of the latest technology.

For example, there is a special laser on the board of Curiosity. It is the pride of engineers who created the device. The laser will allow answering many important questions in Mars exploration. It vaporizes small pieces of the substance for spectral analysis.

Laser or optical quantum generator is a device that transforms pump energy into the energy of a focused radiation flux. The name laser is an abbreviation.

Light Amplification Stimulated Emission of Radiation

 

As the working environment for laser, substances are used in different state of aggregation: solid, liquid, gaseous and plasma.

The electromagnetic wave passing through matter, spend energy on the excitation of atoms of matter. The radiation intensity varies according to the Bouguer law:

 

Since the dependence is exponential, the radiation is quickly absorbed.

Scientists call lasers as a "ready-made solutions to problems that has been unknown yet." Therefore, the use of laser in the study of Mars is expanded especially for spectral analysis. What is the spectral analysis?

The atoms of each chemical element have well-defined resonance frequencies, because of these frequencies they emit or absorb light. This leads to the fact that lines (dark or light) can be visible on spectroscope in certain places, which is characteristic for each substance. The line intensity depends on the amount of a substance and its state.

The example of a line-spectrum, obtained in the study of "space" substances.

Optical spectral analysis is characterized by relative ease of implementation, no complex sample preparation before analysis, a minor amount of a compound (10-30 mg) for analysis on a large number of elements. These are important factors in space research.

Question:


Do you know other areas where laser is used? Have you ever seen the laser?

Climatology

The climate of Mars is the closest to the climate of Earth. Presumably, in the past the climate of Mars could be warm and moist.

There is quite a bit of water vapor in the Martian atmosphere. At low pressure and temperature, it is in a state close to saturation, and therefore goes into the clouds. Only the greatest of clouds are visible in a telescope. However, observations have shown that there are clouds of various shapes and types: pinnate, wavy, leeward (near large mountains and on the slopes of large craters, in places protected from the wind).

There are often foggy over the valleys and at the bottom of craters in the cold days. In the winter of 1979 in the landing site of "Viking-2" the first Martian snow was seen. It has lain for a few months.

The example of temperature distribution on the surface of Mars

The average temperature on Mars is much lower than on Earth, around -40°C. When the most favorable conditions in summer on the daytime half of the planet the air is heated to 20°C. It is an acceptable temperature for the Earth inhabitants. However, in winter frost can reach -125°C at night. Such large temperature differences caused by the fact that the thin atmosphere of Mars is not able to retain heat long. Because of numerous temperature measurements at various points on the surface of Mars, it turns out that the temperature can reach +27°C during a day, but then it drops to -50°C.

There are temperature oases on Mars. In the areas of "lake" Phoenix (plateau of the Sun) and the earth Noah, the temperature ranges from -53°C to +22°C in summer and from -103°C to -43°C in winter.

“Viking” made the first pictures from the surface of Mars. Scientists were very surprised. They were surprised very much to see that the Martian sky is not black as it had been supposed, but pink. Dust that hang in the air absorbs 40% of sunlight, creating a color effect.

"Dust devil"

Wind is one of the reasons of temperature changing. Strong winds often blow above the surface of the planet. The rate of wind can reach 100 m/s. Small force of gravity allows even rarefied airflow to raise huge clouds of dust. Such clouds are called as "dust devils".

Question:


What Earth climatic phenomena can be compared with the Martian "dust devils"?

Geology

Mars is formed from materials, which are similar to those that entered other terrestrial planets.

During the evolution its surface was subjected to an impact of various sizes - from small dust grains to kilometer blocks. Meteorite strikes formed countless craters, and the upper layer of soil was turned into a Martian regolith. Regolith is a reddish dust, small and large debris.

The reddish color of Mars is inherent in all images obtained with telescopes. Over dark or light areas correspond to differences in the composition of the surface, in particular, different iron content.

Water and erosion traces on Mars are very numerous.

Martian terrain.

The thickness of the Martian crust ranges from 40 km to 70 km (at heights).

Topographic map of Mars

The thicker crust (red) is under the huge Tharsis volcanoes, and thinner (dark blue) is a pool Hellas.

First changes in the gullies were discovered in MarsOrbiterCamera images in 2006.

This image shows new deposit in the crater of Gaza in mid-latitudes of the southern hemisphere.

The composition of the infrared spectrum of Mars gives an idea of the rocks types. Basalt is dominated in the southern hemisphere; in the north is an andesite. In the equatorial region are deposits of hematite (their presence is indicative of the impact of water). Streams of lava of Mars contain komatiite and ferropicrite. These rocks are the source of precious and non-ferrous metals: nickel, copper, platinum group metals. Therefore Mars is a promising source of valuable minerals.

Technologies

Space Research (and the planets of the solar system in particular) is one of the most "tech" areas of human activity. The phrase: "It can be used in space" is often perceived as a "This is qualitatively and reliably." There are many "Space" technologies; they affect different areas of innovation and research. Let us try to understand some of them.

Technology "with the place of residence - the orbit."

Speaking of them, first it refers to the Hubble Space Telescope. Its capabilities were used to produce pictures of Mars with the highest resolution ever obtained on Earth. HST can create images of the hemispheres of the planet, which allows simulating weather systems.

Hubble Space Telescope

Many spacecraft was launched to Mars. The most famous of them: Vikings, Mariner, Mars rover, Sojourner, Spirit, Opportunity, and others. Each of them added information available on the planet, said the technical, scientific and technological information in the data base to plan and implement the development program of Mars.

Technology “with the place of residence - Mars."

 

Opportunity was the second of the two rovers launched in 2003 to land on Mars and begin traversing the Red Planet in search of signs of past life. The rover is still actively exploring the Martian terrain, having far outlasted her planned 90-day mission. The name to Opportunity was given by 9 years old girl, within the framework of the NASA traditional competition.

Since landing on Mars in 2004, Opportunity has made a number of discoveries about the Red Planet including dramatic evidence that long ago at least one area of Mars stayed wet for an extended period and that conditions could have been suitable for sustaining microbial life.

The shadow of the Opportunity on the surface of Mars Curiosity is third-generation Mars rover. On August 6, 2012, it literally "fell" on the surface of Mars. The rover was taken within the framework of the research program NASA MarsScienceLaboratory (MSL) directly into Gale Crater.

Curiosity has a mass of 900 kg; it has a maximum value of equipment and slow crawling on Mars, studying its surface.

Curiosity’s "Selfie" in the crater Gale

Technology "with the place of residence - the future."

A manned mission to Mars or colonization is not only the imagination of writers and directors, but also of planned projects, such as:

MarsOne is private project, led by Bass Lansdorpa. It involves a flight to Mars, followed by the base of the colony on the surface and the translation of what is happening on television.

According to the organization, it is not an aerospace company and all work on the development, production and launch of spacecraft will be transferred to subcontractors. The company employs 8 people.

The official website of the project: www.mars-one.com

Inspiration Mars Foundation - fond founded Dennis Tito, plans to send in January 2018, a manned expedition to Mars flyby. The organization plans to use the start of the edge window to start in January 2018 flyby of Mars expedition to return to Earth.

The official website of the project: www.inspirationmars.org

NASA also plans to build a colony on Mars.

Biology

Biology of Mars can be seen in two ways. First, look for an answer to the question "Is life on Mars possible?". Second, to explore the physiological, biological problems at colonization.

Own life on Mars.

Truvelo Etienne was one of the first, who tried to attempt a scientific foundation for the existence of life on Mars. In 1884 he told that the observed changes in spots on Mars may indicate seasonal changes in Martian vegetation.

Many countries are exploring this question seriously.

From November 2009 more than 24,000 meteorites were found on Earth. Martian (ie flown with Mars) are considered to be 34. Researchers conducted by Lyndon B. Johnson Space Center, show that at least three of the identified meteorites contain potential evidence past life on Mars in the form of microscopic structures that resemble fossilized bacteria (called biomorphs).

Photographs taken by rover Curiosity, show objects with a significant resemblance to the "structures" of cyanobacteria on the Earth. This may indicate the microorganisms in water on Mars in the distant past.

fossils photo (Curiosity, NASA)

To date, any theory of space biology does not deny the high probability of the so-called biogenic hypothesis of the origin of detected samples.

In April 2012, scientists’ research was published in the German Aerospace Center (DLR). There were investigated the possibility of the survival of terrestrial organisms in the Martian environment. Lichens and blue-green algae collected in the Alps (at altitudes up to 3500 meters) and Antarctica were placed in an atmosphere having the composition of the Martian. Scientists have reproduced the existing on the surface of the Martian atmospheric composition, soil, pressure, temperature, and solar radiation.

 

The experiment lasted 34 days, during this time lichens and blue-green algae not only survived but continued to photosynthesize. The experiment confirmed that living beings have a chance to survive on Mars in rock crevices and small caves (for UV protection), even after staying there for a long period.

Biological aspects of the Mars colonization.

Man cannot live on the surface of Mars without any protective gear.

Colony project for MarsOne

Recent studies show that there are significant and thus directly available deposits of water ice on Mars. The soil is suitable for growing plants. A sufficiently large amount of carbon dioxide is present in the atmosphere. All this together allows the expectation (if there is enough energy) about the possibility of plant foods production. Also, carbon and oxygen can be produced from local resources, which significantly reduce the need for life-support technology closed loop that would be needed on the Moon, asteroids, or on a remote space station from Earth.

History

The recorded history of Mars observation dates back to the era of the ancient Egyptian astronomers in the 2nd millennium BCE. The Egyptians made the horoscope predictions watching the stars. Celestial bodies were associated with certain gods of their pantheon. Mars, for example, they connected with Gore. Gore often depicted with a bird's head.

Gore -, the ancient Egyptians Mars.

But first calculations the position of Mars made the Babylonian priest-astronomers. They have developed a series of mathematical methods for predicting the position of the planet.

Using these data, scientists have developed the Hellenistic world the heliocentric model that explains the movement of the planets. This model was used until the XVI century.

"The figure of the heavenly bodies" - illustration of a geocentric system of the world, made by the Portuguese cartographer Bartolomeu Velho in 1568. (Kept in the National Library of France).

Indian and Arab astronomers have estimated the size of Mars and its distance from the Earth.

In the XVI century, Nicolaus Copernicus proposed a heliocentric model for the description of the solar system (with a circular planetary orbit). His model was revised by Johannes Kepler, who introduced a more precise elliptical orbit of Mars, coincides with the observed one.

Kepler's heliocentric model (left) and Copernicus (right).

The first telescopic observation of Mars was by Galileo Galilei in 1610. During the XVII century, astronomers have discovered a planet on different surface details. The first map of Mars was published in 1840.

Later lines of water molecules have been detected in the Martian atmosphere. After this discovery is becoming popular thought of the possibility of life on Mars. Percival Lowell, for example, believed that he saw artificial canals on Mars.

In the 1920s, the range of temperatures of the Martian surface was measured. It was found that the surface of Mars is located in the extreme conditions of the desert.

In 1969 was organized the International planetary patrol of seven observatories. They are located relatively evenly in longitude and close to the equator. Patrol Observatory is equipped with the telescopes and cameras with electronic equipment. They monitor clouds and dust storms, and seasonal changes in the surface of Mars.

Missions to Mars, both failed and successful

Since the 1960s began launching unmanned interplanetary probes to study the planet, beginning from the trajectory-flight, and then from the orbit of an artificial satellite, and directly on the surface.

From the 1950s it was began to be developed projects of manned missions to Mars. But the "Moon race" (a competition between the Soviet Union and the United States to study the Moon) pushed them into the background.

Color map of Mars with a high separation capacity (based on images created with a "Viking" orbiter)

Since 2010, the Ames Research center developed a project «Hundred-YearStarship». The main idea of the project is to send people to Mars permanently. This will lead to a significant reduction in the cost of the flight; it will be possible to take more cargo and crew. According to calculations, to send four astronauts to Mars and bring them back will cost as much to send 20 people and leave them. The whole expedition would cost $ 750 billion. It can be halved if astronauts will not be returned on Earth.

Business

There are three projects of Mars colonization. Detailed information about the cost of each phase of the project has not been disclosed, but the estimated cost of the whole project is available to the public. The cost of these projects is measured in billions of dollars, with the bulk of the spending is on the stage of implementation. This is due to "high cost" of origin of goods on the orbit. To send and return 100 kg of cargo is about 200 million dollars. Projects that do not involve the return of the mission on the Earth cut the figure to 100 million dollars.

Optimization of the "weight" of the mission is a way to reduce its distribution costs.

 

Mars exploration projects are expensive and ambitious. The near future will show which of them will be realized and may bring profit, and not only "scientific dividends." Development of Mars can give not only the most valuable natural resources, but also the opportunity to cultivate new species of cultivated plants and microorganisms, exercise techniques that are impossible on Earth.

Lesson summary

Name

Содержание

1

As a result of Case Knowledge Hypermarket can add the following findings of students:

 

2

What are the 3 most significant sites help getting information?

http://edufuture.biz/

http://galspace.spb.ru/index41.html

https://ru.wikipedia.org/wiki/%D0%9C%D0%B0%D1%80%D1%81

 

3

To help the student and coach:

http://edufuture.biz/

http://galspace.spb.ru/index41.html

http://www.sai.msu.su/ng/solar/mars/latest_after1996.html

https://www.youtube.com/watch?v=RkMCAjQ4LLE

 

4

Where to take information of the Case:

http://edufuture.biz/

http://galspace.spb.ru/index41.html

http://www.sai.msu.su/ng/solar/mars/latest_after1996.html

https://www.youtube.com/watch?v=RkMCAjQ4LLE

http://galspace.spb.ru/index41.html

http://www.mars-one.com/

http://www.inspirationmars.org/

https://www.nasa.gov/centers/ames/home/index.html

http://galspace.spb.ru/orbita/12.htm
https://ru.wikipedia.org/wiki/%D0%93%D0%BE%D0%BC%D0%B0%D0%BD%D0%BE%D0%B2%D1%81%D0%BA%D0%B0%D1%8F_%D1%82%D1%80%D0%B0%D0%B5%D0%BA%D1%82%D0%BE%D1%80%D0%B8%D1%8F

http://texnomaniya.ru/dobicha-poleznih-iskopaemih-na-marse

 

5

Locations of the lesson:

Кейс - урок проходит в классе. Возможно проведение в музее, библиотеке.

6

Race:

Teams of boys and girls.

Targets for them:

7

Hometask:

по пять вопросов к материалу кейса (индивидуальное задание).

8

Duration of Case:

90 мин (спаренный урок)

 

9

Ability to circuit classes with student-double for: 

возможно.

10

The results produced and competence:

 

Умение быстро найти необходимую информацию по теме;

Получение практических навыков применения полученной информации.

11

Tags:

 

redox reactions , gravity , acceleration, laser, Bouguer's law , the optical spectrum , relief, telescope,

cyanobacteria , lichens .

12

Authors:

 Грабовская Лариса Леонидовна

13

Took part in case apgrade:

 

The End

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