International Space Station
Crew Return Vehicle: X-38
Acrobat version of this entire brief is available. This version preserves
all formatting of the original hardcopy; it will provide an easy source
for downloading a printable version of this activity.
reader for the Acrobat file is available online.
The International Space Station (ISS) will provide the world with an
orbiting laboratory that will have long-duration micro-gravity experimentation
capability. The crew size for this facility will depend upon the crew
return capability. The first crews will consist of three astronauts from
Russia and the United States. The crew is limited to three because the
Russian Soyuz vehicle that will remain docked to the ISS can only hold
three people. It is imperative that the crew members be able to return
to Earth if there is a medical emergency or if other complications arise.
In development at this time is a Crew Return Vehicle that will be able
to hold up to seven crew members. This will allow the full complement
of seven astronauts to live and work onboard the ISS.
The Crew Return Vehicle, or X-38, uses a lifting body concept originally
developed by the U.S. Air Force in the mid-1960s. These wingless lifting
bodies attain aerodynamic stability and lift from the shape of the aircraft.
Lift results from more air pressure on the bottom of the body than on
the top. Following the jettison of a deorbit engine, the X-38 will glide
from orbit and use a steerable, parafoil parachute for its final descent
to landing. The high speeds at which lifting body aircraft operate make
it dangerous to land. The parafoil is used to slow the vehicle down and
make it safer. Its landing gear con-sists of skids rather than wheels.
The skids work like sleds so the vehicle will glide to a stop on the ground.
Both the shape and size of the X-38 are different from the traditional
Space Shuttle. The Crew Return Vehicle can fit into the payload bay of
the Space Shuttle. This does not, however, mean it is small. The X-38
weighs 10,660 kg and is 9.1 meters long. The battery system, which will
keep its charge for nine hours, is used for power and life support. If
the Crew Return Vehicle is needed, it will only take two to three hours
for it to reach Earth.
The parafoil parachute, employed for landing, is derived from technology
developed by the U.S. Army. This massive parafoil deploys in stages for
optimum performance. A drag chute will be released from the rear of the
X-38. This drag chute is used to stabilize and slow the vehicle down.
The giant parafoil—which has an area of 687 square meters—is then released.
It will open in four stages (a process called staging). While the staging
process only takes 45 seconds, it is important for a successful chute
deployment. Staging prevents high-speed winds from tearing the parafoil.
The spacecraft’s landing is completely automated. Mission Control sends
coordinates to the onboard computer system. This system will also use
wind sensors and the Global Positioning System (a satellite-based coordinate
system) to coor-dinate a safe trip home. Since the Crew Return Vehicle
was designed with medical emergencies in mind, it makes sense that the
vehicle can find its way home automatically in the event that crew members
are incapacitated or injured. If there is a need, the crew will have the
capability to operate the vehicle by switching to the backup systems.
Some of the technologies used for the creation of the X-38 have come
from many places and are not new. Combining these technologies with new
ideas and capabilities has created a vehicle that will be tasked with
the mission of carrying home the crew of the ISS if there is an onboard
emergency. By utilizing technologies from the 1960s in the 1990s and by
being fast, safe, and dependable, the Crew Return Vehicle will provide
peace of mind to all those who will live and work onboard the ISS.
Construct A Parafoil
To construct a parafoil similar to the one that will be used for the X-38.
To test the parafoil's performance capabilities.
|| Physical Science: Motions
Science and Technology: Abilities of technological design
Computation and estimation
- Paper pattern*
- Sewing thread
- Cellophane tape
- Glue stick
- Weights (different sized metal washers and nuts)
- Metric ruler
- Sharp knife
- Cutting surface
- Cut out the paper pattern for the parafoil.
- Use the sharp knife to cut small slots for the tabs. It may be necessary
to assist younger students with this step.
- Prefold the parafoil on the dashed lines.
- Insert the tabs marked "port" and "starboard"
into their corresponding slots.
- Hold the tabs securely by taping them on the inside of the parafoil.
- Fold the left and right sides of the parafoil together so that the
flaps come together. Spread glue on the inside of the flaps and press
- Fold over the flap and glue it to the lower side of the center airfoil
to hold it together.
- Bend the port and starboard airfoils slightly downwards so that they
join the center airfoil along the edges. Make sure the tabs are slipped
inside the model for strength. Hold the airfoils together with a small
amount of cellophane tape.
- Attach two pieces of thread to the front and back of each side with
a small piece of tape. Each thread should be 30 centimeters long.
- Tie the ends of the threads together and then tie a weight to the
|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.
- Hold the parafoil off the floor and drop it. Observe how it flies.
- Make adjustments to improve the parafoil's flight. Possible adjustments
- Tying the weight higher up on the threads
- Adjusting the flaps up or down
- Using a heavier or lighter weight
- Shortening or lengthening the front or back threads to change the
angle of the parafoil to the vertical
Measure how far the parafoil glides when dropped from a given altitude.
Graph the glide distance of the parafoil with different weights.
Compare and contrast the operation of a parafoil with a traditional parachute.
Small parachutes can be made from circles cut from plastic grocery bags.
Attach threads with tape and hang a weight from the ends.
* The shaded small rectangles on the leading edge of the parafoil represent
the open cells in the real parafoil that take in air so that the parafoil