1. Welcome to the Challenger Learning Center!

2. On January 28, 1986, the seven crew members of the Space Shuttle Challenger/STS-51L “Teacher in Space” mission set out to broaden educational horizons and advance scientific knowledge. Their mission exemplified man’s noblest and most wondrous qualities – to explore, discover, and teach. Members of the crew were Commander Francis R. (Dick) Scobee, Pilot Michael J. Smith, Mission Specialists Judith A. Resnik, Ellison S. Onizuka, Ronald E. McNair and Payload Specialists Gregory B. Jarvis and S. Christa McAuliffe. To the nation’s shock and sorrow, their Space Shuttle exploded 73 seconds after liftoff.
In the aftermath of the Challenger accident, the crew’s families came together, firmly committed to the belief that they must carry on the spirit of their loved ones by continuing the Challenger crew’s educational mission. In April 1986, they created Challenger Center for Space Science Education (Challenger Center).
They envisioned a place where children, teachers and citizens alike could touch the future: manipulate equipment, conduct experiments, solve problems, and work together-immersing themselves in space-like surroundings. The goal: to spark youth interest and joy in science and engineering; a spark that could change their lives. The result: the creation of a Challenger Learning Center.
The first Challenger Learning Center opened in Houston in August The St. Louis Center opened in Today, there are more than 40 Learning Centers in the U.S., Canada, South Korea, and the United Kingdom. Collectively, these centers reach more than 400,000 middle-school aged students and 40,000 teachers each year. Since 1986, Challenger Center has impacted more than 4 million students. It maintains strong partnerships with NASA, other federal agencies, universities and the aerospace industry who help keep curriculum current. More details on the national organization can be found at More details on the Challenger Learning Center St. Louis can be found at
Challenger 51-L
January 28, 1986

3. Christa McAuliffe
This is Christa McAuliffe, a New Hampshire teacher & the first Space Shuttle passenger/observer participating in the NASA Teacher in Space Program.
She had planned to teach lessons during live television transmissions.
The 51-L crew gathered data from Comet Halley, Christa McAuliffe, the first teacher in space, was given the responsibility of telling students across America what they were learning about the comet.

4. “…The Challenger Crew was pulling us into the future and we will continue to follow them.”
-- President Ronald Reagan
This quotation is from President Ronald Reagan’s address to the nation on January 28, 1986, the day of the Challenger disaster.

5. We are very glad to have you join us to Rendezvous With a Comet.

6. Comet Halley Comet Encke Next approach: July 2061
Perhaps the most famous comet you have heard of is Comet Halley, named for Edmond Halley who computed its orbital period enabled it to be seen from Earth every 76 years. A much smaller comet, Encke, is the comet our simulated mission is scheduled to rendezvous with. As you see in the images, it’s much smaller than Halley’s Comet.
Comet Halley
Next approach: July 2061
Comet Encke
Next approach: October 2013

7. Why Study Comets? Scientific Research
Prevent a comet from colliding with Earth
Potential resources for future missions
Why does NASA send missions to study comets? There are many reasons: scientific research to learn more about the origins and workings of the universe; to learn more about the behavior of comets to help prepare a strategy to prevent a comet from colliding with Earth. It is believed that fragments from Comet Encke impacted an isolated area of Russia in 1908 causing the largest impact event on or near Earth in recorded history. Another reason to study comets is to see if they have potential resources that could be used for future missions in space.

8. Comet Facts Comets are made of: Ice Rock Dust Gases
How comets get their names
Named for the person who observed the comet and analyzed its orbital path
Names assigned by the International Astronomical Union
Short period/long period
< 200 years = short period
> 200 years = long period
Comets are made up of four components: ice, rock, dust and gases. The goal of the mission to Comet Encke is to launch a probe to land on the comet and retrieve samples of its components.
Comets most often are named for the person who first observed them, but sometimes they are named for the person who first analyzed its orbital path. The second option is true of both Comet Halley and Comet Encke. Though originally observed and recorded by Pierre Mechain in 1786, Comet Encke is actually named for Johann Franz Encke who successfully calculated its orbital period in 1819.
Comets are divided into two broad categories based on their orbital period. Short period comets have an orbital period less than 200 years long. The orbits of long period comets last more than 200 years.

9. Anatomy of a Comet Nucleus Blue Gas Tail Coma White Dust Tail
A comet’s anatomy includes the following parts:
Nucleus – Often only a few kilometers across, contains the solid materials: ice, rock and dust. The diameter of Comet Encke’s nucleus is 4.8km.
Coma – can reach up to 1,000,000 miles across; made of sublimated water and carbon dioxide vapors
Tails – can reach up to 100,000,000 miles long; made of dust released from nucleus (white tail) or gas pushed back from coma (blue tail)
Nucleus
Blue Gas Tail
Coma
White Dust Tail

10. Comet Encke Discovered by Johann Franz Encke in 1819
Orbital Period: 3.3 years
Magnitude: 7
Eccentricity:
Mass Density: 0.6 g/cm3
This image shows the orbital path of Comet Encke which comes into view on Earth every 3.3 years. That is the shortest orbital period of any known comet.
Magnitude of a comet refers to its brightness/visibility in the sky. At a magnitude of 7 Comet Encke can be seen with a pair of binoculars or a telescope.
Eccentricity refers to the shape of a comet’s orbit. A value of zero is a circular orbit and values between 0 and 1 belong to objects with an elliptical orbit.
The density of a substance is its mass per unit of volume. Comet Encke’s mass density is near the average for comets. Because of their low mass, comet nuclei do not become spherical under their own gravity, so they have irregular shapes.

11. OBJECT MAGNITUDE MASS DENSITY GASES ECCENTRICITY
(scale of brightness)
MASS DENSITY
(mass per unit volume)
GASES
ECCENTRICITY
(range of 0 to 1; 0 = circle)
Meteor
Asteroid
Comet
Supernova
Planet
- 4 to + 0.7
0.7 to 5.4 g/cm3
CO2, H2, He2, N2
0.0 to 0.2
- 15 to + 6
varies
He2, H2, C, N2, O2
None
- 1.7 to + 11
0.4 to 0.9 g/cm3
CO, NH3, CH4, H, CN, CO2, O2, N2
Less than 0.98 =
short period comet
Greater than 0.98 =
long period comet
+ 4.5 to
0.7 to 5.4 g/cm3
none detected
0.0 to 0.3
- 8 to + 6
1.0 to 8.0 g/cm3
none detected
None
This chart compares the magnitude, mass density, and eccentricity of different objects in space so you can see how they are similar to, and different from, comets. Also included in this chart are gases that you would most often find on each kind of object. Can you identify the type of gas from its chemical element abbreviation on the chart?

12. NASA Comet Missions Mission Name Launch Date Galileo October 18, 1989
Deep Space 1
October 24, 1998
Stardust
February 7, 1999
Contour
July 3, 2002
Rosetta
March 2, 2004
Deep Impact
January 12, 2005
Deep Impact/Epoxi
October 11, 2010
Here is a list of previous NASA missions that investigated a comet. More information about each of these missions and future potential exploration of comets can be found at NASA’s website,

13. Good Luck On Your Mission! Good Luck On Your Mission!
We are very glad to have you with us on our mission set for October 23, See you then!