Module 4 - Lesson 9

Module 4 - Lesson 9

Plan a mission to a recently discovered planet

Module 4: The Planets

Timeframe:

This lesson will require approximately four class periods (~50):

l two for research and preparation of presentations

l one for presentations

l one for closing discussion

/debate

TEKS(11) Science concepts. The student knows that organisms maintain homeostasis. The student is expected to:

(B) investigate and identify how organisms, including humans, respond to external stimuli;

(6) Science concepts. The student knows the structures and functions of nucleic acids in the mechanisms of genetics. The student is expected to:

(A) describe components of deoxyribonucleic acid (DNA), and illustrate how information for specifying the traits of an organism is carried in the DNA;

(B) explain replication, transcription, and translation using models of DNA and ribonucleic acid (RNA);

Lesson Overview:

Through role play, students will engage in a space planning mission. While planning their mission to a newly discovered planet, groups will need to consider one of many factors, including spacecraft design, distances in space, mission supplies, and qualifications for life-sustaining planets.

Materials and Resources:

l Cooperative Learning Rubric

l books

l magazine

l websites about manned space travel

Vocabulary:

l Astronomy Glossary

Background Information:

Mars is the fourth planet from the Sun and the seventh largest:

orbit: 227,940,000 km (1.52 AU) from Sun

diameter: 6,794 km

mass: 6.4219e23 kg

Mars (Greek: Ares) is the god of War. The planet probably got this name due to its red color; Mars is sometimes referred to as the Red Planet. (An interesting side note: the Roman god Mars was a god of agriculture before becoming associated with the Greek Ares; those in favor of colonizing and terraforming Mars may prefer this symbolism.) The name of the month March derives from Mars.

Mars has been known since prehistoric times. Of course, it has been extensively studied with ground-based observatories. But even very large telescopes find Mars a difficult target, it's just too small. It is still a favorite of science fiction writers as the most favorable place in the Solar System (other than Earth!) for human habitation. But the famous "canals" "seen" by Lowell and others were, unfortunately, just as imaginary as Barsoomian princesses.

Viking 2 Landing Site

Pathfinder Landing Site

The first spacecraft to visit Mars was Mariner 4 in 1965. Several others followed including Mars 2, the first spacecraft to land on Mars and the two Viking landers in 1976. Ending a long 20 year hiatus, Mars Pathfinder landed successfully on Mars on 1997 July 4. In 2004 the Mars Expedition Rovers "Spirit" and "Opportunity" landed on Mars sending back geologic data and many pictures; they are still operating after more than a year on Mars. Three Mars orbiters (Mars Global Surveyor, Mars Odyssey, and Mars Express) are also currently in operation.

Mars' orbit is significantly elliptical. One result of this is a temperature variation of about 30 C at the subsolar point between aphelion and perihelion. This has a major influence on Mars' climate. While the average temperature on Mars is about 218 K (-55 C, -67 F), Martian surface temperatures range widely from as little as 140 K (-133 C, -207 F) at the winter pole to almost 300 K (27 C, 80 F) on the day side during summer.

Though Mars is much smaller than Earth, its surface area is about the same as the land surface area of Earth.

Olympus Mons

Mars has some of the most highly varied and interesting terrain of any of the terrestrial planets, some of it quite spectacular:

• Olympus Mons: the largest mountain in the Solar System rising 24 km (78,000 ft.) above the surrounding plain. Its base is more than 500 km in diameter and is rimmed by a cliff 6 km (20,000 ft) high.

• Tharsis: a huge bulge on the Martian surface that is about 4000 km across and 10 km high.

• Valles Marineris: a system of canyons 4000 km long and from 2 to 7 km deep (top of page);

• Hellas Planitia: an impact crater in the southern hemisphere over 6 km deep and 2000 km in diameter.

Much of the Martian surface is very old and cratered, but there are also much younger rift valleys, ridges, hills and plains. (None of this is visible in any detail with a telescope, even the Hubble Space Telescope; all this information comes from the spacecraft that we've sent to Mars.)

Southern Highlands

The southern hemisphere of Mars is predominantly ancient cratered highlands somewhat similar to the Moon. In contrast, most of the northern hemisphere consists of plains which are much younger, lower in elevation and have a much more complex history. An abrupt elevation change of several kilometers seems to occur at the boundary. The reasons for this global dichotomy and abrupt boundary are unknown (some speculate that they are due to a very large impact shortly after Mars' accretion). Mars Global Surveyor has produced a nice 3D map of Mars that clearly shows these features.

The interior of Mars is known only by inference from data about the surface and the bulk statistics of the planet. The most likely scenario is a dense core about 1700 km in radius, a molten rocky mantle somewhat denser than the Earth's and a thin crust. Data from Mars Global Surveyor indicates that Mars' crust is about 80 km thick in the southern hemisphere but only about 35 km thick in the north. Mars' relatively low density compared to the other terrestrial planets indicates that its core probably contains a relatively large fraction of sulfur in addition to iron (iron and iron sulfide).

Like Mercury and the Moon, Mars appears to lack active plate tectonics at present; there is no evidence of recent horizontal motion of the surface such as the folded mountains so common on Earth. With no lateral plate motion, hot-spots under the crust stay in a fixed position relative to the surface. This, along with the lower surface gravity, may account for the Tharis bulge and its enormous volcanoes. There is no evidence of current volcanic activity, however.

Valley Network

There is very clear evidence of erosion in many places on Mars including large floods and small river systems. At some time in the past there was clearly some sort of fluid on the surface. Liquid water is the obvious fluid but other possibilities exist. There may have been large lakes or even oceans; the evidence for which was strenghtened by some very nice images of layered terrain taken by Mars Global Surveyor and the mineralology results from MER Opportunity. Most of these point to wet episodes that occurred only briefly and very long ago; the age of the erosion channels is estimated at about nearly 4 billion years. However, images from Mars Express released in early 2005 show what appears to be a frozen sea that was liquid very recently (maybe 5 million years ago). Confirmation of this interpretation would be a very big deal indeed! (Valles Marineris was NOT created by running water. It was formed by the stretching and cracking of the crust associated with the creation of the Tharsis bulge.)

Early in its history, Mars was much more like Earth. As with Earth almost all of its carbon dioxide was used up to form carbonate rocks. But lacking the Earth's plate tectonics, Mars is unable to recycle any of this carbon dioxide back into its atmosphere and so cannot sustain a significant greenhouse effect. The surface of Mars is therefore much colder than the Earth would be at that distance from the Sun.

Mars has a very thin atmosphere composed mostly of the tiny amount of remaining carbon dioxide (95.3%) plus nitrogen (2.7%), argon (1.6%) and traces of oxygen (0.15%) and water (0.03%). The average pressure on the surface of Mars is only about 7 millibars (less than 1% of Earth's), but it varies greatly with altitude from almost 9 millibars in the deepest basins to about 1 millibar at the top of Olympus Mons. But it is thick enough to support very strong winds and vast dust storms that on occasion engulf the entire planet for months. Mars' thin atmosphere produces a greenhouse effect but it is only enough to raise the surface temperature by 5 degrees (K); much less than what we see on Venus and Earth.

Developing the Lesson:

Anticipatory Set

Open class with a "news flash" about a new mission to the Red Planet. Until recently, this planet has been unreachable due to financial and technological restraints, but new improvements in space flight technology have provided means to traverse space to reach our closest neighbor. Several nations are now working together to compile a team of astronauts and scientists for an exploratory mission to Mars, and need help in planning the mission.

Introduction

Your students' assignment is to assist this international team by

researching the following:

spacecraft design
distances in space
concerns for astronauts on a long-term mission
qualifications for life-sustaining planets and what mars needs to be so

Explain the parameters of the assignment as follows:

the class will be divided into four groups. Each group will be responsible for one of four research areas:

1. spacecraft design: students should look at past

lunar missions and deep space probes (i.e.,

Voyager) to determine spacecraft requirements for

cargo/supply transport, long flights and unassisted

take-off and landing. Keep in mind life support systems.

2. distances in space: students should research

relative distances between Earth and other planets

in our solar system, determining from this the

approximate length of time necessary to reach the

new planet. Students should also plan when to launch the space ship in order to reach Mars at the right time in space.

3. concerns for astronauts on a long-term mission:

students will need to research past lunar missions

(Apollo) to determine those items necessary for a

long-term manned mission in space -- consider

things such as food, water, waste management,

fuel, exercise equipment, air recycling,

maintenance/repairs, etc.

4. qualifications for life-sustaining planets: students

should answer this question by considering our

home planet's resources, and determining which

elements are necessary for sustaining human,

animal, and plant life. Consider factors such as:

distance from the Sun; surface conditions;

atmospheric conditions (both for air and for

protection from asteroids and from the Sun's

harmful rays); presence of water (either frozen or

liquid); etc. They Should also recognize what Mars doesn’t have and be able to find solutions to these issues.

- refer students to the Cooperative Learning Rubric, by

which they will be evaluated. Students will be expected to

participate fully in their group's assigned topic, debating

and contributing to the group's progress.

- students (at the teacher's discretion) may be instructed to

either display their findings in poster format, overheads, or

may simply prepare an oral presentation of their research

for the class.

- Allow students approximately two class periods to research and

prepare their findings for the class, after which time one class

period should be allotted for group presentations.

Hands-on Activity

Students must first plan their research strategy and task assignments and check it over with the teacher before beginning. Students will then have approximately three classes to complete their research and to prepare their presentation. Short skits,

multimedia presentations, or simple posters may be used in the presentations.

Check for Understanding

The teacher will spend about 10 minutes with each group double checking their research strategies and offering suggestions to help students get started.

Independent Practice

Since students will be working in rather large groups, most of the work will be done during class time. There will of course be the option to practice and work outside of class but not required.

Closure:

Allow a final class period for a whole-class discussion regarding the plausibility

of such a mission, given the fact that humans have (as yet) not ventured

beyond the Moon on manned missions. Students will should consider the

following questions:

1. Is a longer mission possible?

2. Should deep space manned missions be a goal of space programs in

Canada and internationally?

3. Since space programs can be very dangerous, is it right to place lives at risk for the advancement of science?

4. Since space programs can be very expensive, is it right to spend

millions and billions of dollars for the pursuit of science?

Given the "political" nature of such questions, the teacher may wish to

structure the closure lesson in a debate format.

Extension:

As an extension activity, students could be asked once they have arrived on the planet, what physical characteristics an alien on such a planet might need to have to survive. Students should consider temperature, ice-covered surface, small influence from gravity, access to direct sunlight (rotational period), etc.

Evaluation:

Evaluate students' group work based upon the Cooperative Learning Rubric.

Cooperative Learning Rubric and the presentation rubric.



Student Name: ________________________________________

CATEGORY	4	3	2	1
Quality of Information	Information clearly relates to the main topic. It includes several supporting details and/or examples.	Information clearly relates to the main topic. It provides 1-2 supporting details and/or examples.	Information clearly relates to the main topic. No details and/or examples are given.	Information has little or nothing to do with the main topic.
Amount of Information	All topics are addressed and all questions answered with at least 2 sentences about each.	All topics are addressed and most questions answered with at least 2 sentences about each.	All topics are addressed, and most questions answered with 1 sentence about each.	One or more topics were not addressed.
Diagrams & Illustrations	Diagrams and illustrations are neat, accurate and add to the reader's understanding of the topic.	Diagrams and illustrations are accurate and add to the reader's understanding of the topic.	Diagrams and illustrations are neat and accurate and sometimes add to the reader's understanding of the topic.	Diagrams and illustrations are not accurate OR do not add to the reader's understanding of the topic.
Notes	Notes are recorded and organized in an extremely neat and orderly fashion.	Notes are recorded legibly and are somewhat organized.	Notes are recorded.	Notes are recorded only with peer/teacher assistance and reminders.
Internet Use	Successfully uses suggested internet links to find information and navigates within these sites easily without assistance.	Usually able to use suggested internet links to find information and navigates within these sites easily without assistance.	Occasionally able to use suggested internet links to find information and navigates within these sites easily without assistance.	Needs assistance or supervision to use suggested internet links and/or to navigate within these sites.
Sources	All sources (information and graphics) are accurately documented in the desired format.	All sources (information and graphics) are accurately documented, but a few are not in the desired format.	All sources (information and graphics) are accurately documented, but many are not in the desired format.	Some sources are not accurately documented.
Presentation	All members full participate equally sharing the responsibilities involved with the project	All members particpate in the presentation, but to a varying degree of speaking and developement.	Some members of the group participate and some do not.	Only one person particpates in the presentation.

Teacher Relections:

_______________________________________________________________