National Aeronautics and

Space Administration

Educational Product

Educators Grades 5–12

Educational Brief

Connecting in Space: Docking With the

International Space Station

EB-1998-27-126-HQ 1 Connecting in Space

Objectives

Students will demonstrate and identify procedures, selecting the best method to complete the docking activity.

Students will identify Newton’s Laws of Motion.

EB-1998-07-126-HQ Connecting in Space

Science Standards

Science as Inquiry

Physical Science

Motions and forces

Position and motion of objects

Math Standards

Problem Solving

Communication

Materials (for each group of two)

String, 4.6 meters

Pencil, sharpened

Tape

Space Shuttle template

Stand-off cross and docking ring template 

2 small plastic cups

Straw

Clay

Background Information

The International Space Station will provide a long-term orbital laboratory in which research in biology, chemistry, physics, and other sciences will be conducted. With an approximate mass of 456,620

kilograms when it is complete, the International Space Station will be

the largest object humans have built in orbit. Forty-five space flights

are required to assemble this orbiting laboratory. These flights will

occur over a 5-year period.

There are three phases to the development of the International Space

Station. Phase One encompasses U.S. participation in the Russian

Mir space station project. Having astronauts live aboard Mir with the

Russian cosmonauts enables the United States to study the longterm effects of space on the human body and to practice procedures

that will be used on the International Space Station. Phase Two of

production for the International Space Station consists of the first

portion of assembly, while Phase Three is the second portion of

assembly. 

In order for the components, crews, and supplies to be delivered to

the International Space Station, a system needs to be in place that

allows the Space Shuttle to dock, or attach, to the structure. One

procedure practiced on Mir includes the docking techniques. After

the Space Shuttle is launched and once inserted into an initial orbit,

the Commander uses the Orbital Maneuvering System to thrust the

Space Shuttle from one orbit to another. Using the Orbital

Maneuvering System and Reaction Control System, the Space

Shuttle is positioned approximately 110 meters below Mir. The

Reaction Control System is used to complete the approach of the

Space Shuttle toward Mir. The Reaction Control System is used to

change speed, orbit, and attitude (pitch, roll, and yaw.) The pitch is

an angular rotation about an axis parallel to the widthwise axis of a

vehicle. The roll is the angular rotation movement about the lengthwise axis of the vehicle. The yaw is the angular rotation movement

about the heightwise axis of the vehicle. The Reaction Control

Systems are located in the nose and tail sections of the Space

Shuttle. When the systems are activated, they are fired in a direction

opposite to that which the Commander wishes to move. If the

Commander wants to move to the left, he or she fires the Reaction

Control System on the right, and if the desired movement is to the

right, the system is fired on the left. The Space Shuttle travels toward

Mir with a force that is equal and opposite to the Reaction Control

System firings (Newton’s Third Law).

The Space Shuttle stops within 50 meters of Mir, which is approximately one-half the length of a football field. From that position the

Space Shuttle waits for clearance from Mission Control to continue.

When the command is given to continue, the Reaction Control

System is activated again and the Space Shuttle closes in on Mir at a

speed of about 0.05 meters per second until it reaches a distance of

about 9 meters. There, the Space Shuttle stops again and waits for

approximately 5 minutes. The Commander and Pilot make sure they

can see the docking target clearly and fine-tune the alignment of the

Space Shuttle with the docking target. A large black cross called the

Stand-off-Cross is mounted 30 centimeters (cm) above the back

plate in the center of the target. When the Commander has the

Stand-off Cross squarely in line with the docking target, he or she

Pitch

Yaw

Roll –

+

– +

+ –
EB-1998-07-126-HQ Connecting in Space

maneuvers the Space Shuttle and makes contact with the docking

ring. Once a series of hooks is engaged, the Space Shuttle is then

successfully docked with Mir. It takes about 2 hours for the passage

between the Space Shuttle and Mir to pressurize. After the passage

is pressurized, the hatch is opened and the crews exchange greetings and supplies.

These procedures, which have been learned during Phase One of

the International Space Station, have been invaluable to astronauts

and supporting ground crews. With the knowledge gained through

cooperation, these procedures will secure the future success of the

International Space Station for years to come.

Astronauts must understand the three important scientific principles

that govern the motion of all objects whether on Earth or in space.

These were described by English scientist Sir Isaac Newton in 1687

and are now called Newton’s Laws of Motion. In simple form, they

are:

1. Objects at rest will stay at rest and objects in motion will stay

in motion in a straight line unless acted upon by an unbalanced

force.

Newton’s First Law of Motion is demonstrated by the Space Shuttle

using the Reaction Control System to align itself with Mir. If the system were not used, the Space Shuttle would continue to move in its

orbit instead of changing position to encounter Mir.

2. Force is equal to mass times acceleration.

This equation is used to determine how much force is needed to

move the Space Shuttle from one position to another.

3. For every action there is always an opposite and

equal reaction.

A good example of this law is the use of the Reaction Control

System. When the Commander wants to move the Space Shuttle to

the left, he or she fires the system on the right, and if the movement

needs to be to the right, the system fires on the left.

Docking Activity

Invite two students to demonstrate the activity for the class.

Introduce the Space Shuttle on a string apparatus. Help the students

tie the loose end of the string around their waists as illustrated in the

drawing. Place an empty, small plastic cup on the floor between the

two students. Tell the students the cup represents the docking ring

on the Mir space station. Explain that their task or mission is to get

the orbiter inside the cup without tipping the cup over. The students

may not use their hands. Allow them to demonstrate for the class.

They will find teamwork is very important as they decide how to

maneuver. Different techniques are to move back and forth, move

closer together, and bend at the knees. Students should experiment

to find the best and quickest way to dock the orbiter. 

After demonstrating the activity, show the illustration and have the

students estimate how long a string they will need to tie between

them. Make sure each team has a copy of the Shuttle template and

instruct them to tape the cut-out Space Shuttle orbiter onto a sharpened pencil. The sharpened end of the pencil needs to be at the

nose or front of the orbiter. Have the students estimate the length of

string that will be needed to tie the orbiter to the string that connects

the students. Allow students time to practice the docking maneuver.

When the students have practiced docking, bring the class together

and discuss what problems may have occurred and how those problems were solved. Discuss Newton’s Laws of Motion, and have the

students give examples of those laws in their docking procedure.

For older students:

Copy the docking target, and enlarge the Stand-off Cross to

150 percent on heavy paper. Have the students cut out the docking target. Construct a docking apparatus by placing a piece of

clay at one end of a straw. Affix this to the bottom of a small cup.

Put a small hole through the docking target, and slide it over the

straw. The straw should be tall enough to protrude 2–3 cm above

the docking target (i.e., above the bottom of the cup). Identify the

center of the Stand-off Cross. Mount the center of the cross on

top of the straw over the center of the docking target. The cross

should be 2–3 cm above the target. It needs to be below the top

of the cup. The top of the cup simulates the actual docking ring,

which is the surface that is contacted by the Space Shuttle docking system capture ring. 

Have the students dock the orbiter using the same techniques as

stated for younger students. When dockings have been practiced

with two students, a third student might be added. This student

would stand directly over the docking target and Stand-off Cross

and control the string with the orbiter attached. This student would

communicate to the other students what they need to do in order to

line up to dock. This student would communicate to the two students attached to the string which way to move to line up with the

Stand-off Cross. The center student would use his or her hands on

the string to control the orbiter movement in an up-and-down

motion and thus control the docking. These three students simulate

the x, y, and z axes (roll, pitch, and yaw) used in docking the Space

Shuttle in orbit.

Assessment:

Each group will prepare a demonstration to show which techniques

they found to be the best procedure. In this demonstration, they

should state the reasons they chose this procedure. The students

should discuss which of Newton’s Laws of Motion pertain to the

activity.

Extensions:

1. Restrict students’ view of the docking ring by using glasses or a

headband that has blinders affixed to the sides, such as those

used for horses. Then they should practice the activity with their

vision impaired.

2. Use a shorter string for the docking string.

3. Use a different size cup: taller, smaller, larger, different shape.

4. Use two-way radio and/or video camera to simulate actual

communication with Mission Control.

For more information about the International Space Station, please

visit: http://station.nasa.gov

Please take a moment to evaluate this product at

http://ehb2.gsfc.nasa.gov/edcats/educational_brief

Your evaluation and suggestions are vital to continually

improving NASA educational materials. Thank you.

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EB-1998-07-126-HQ Connecting in Space

Note: Two copies of the Shuttle orbiter are provided for ease in duplication.

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