[dramatic percussion music]
- HEY, THERE. WELCOME TO "NASA LAUNCHPAD."
I'M YOUR HOST, JUSTIN TULLY.
SO WHAT'S THE FURTHEST YOU'VE EVER BEEN AWAY FROM HOME?
FOR SOME OF YOU, THAT MIGHT JUST BE
A COUPLE MILES FROM YOUR HOUSE.
OR YOU MIGHT HAVE GONE FROM ONE COAST TO THE OTHER.
OR MAYBE YOU'VE EVEN GONE OVERSEAS.
BUT, HEY, NONE OF YOU HAVE GONE NEARLY AS FAR
AS SOME OF NASA'S MISSIONS.
I MEAN, LET'S JUST LOOK AT ANY OF THE APOLLO MISSIONS.
ONE WAY FROM THE EARTH TO THE MOON
IS ABOUT 385,000 KILOMETERS, WHICH IS ROUGHLY 239,000 MILES.
239,000 MILES?
I'LL BE LUCKY IF MY CAR CAN MAKE IT TO 200,000.
WELL, EVEN THE MOON ISN'T TOO FAR AWAY
IN THE GRAND SCHEME OF THINGS.
I MEAN, NASA HAS SENT MISSIONS TO MARS, JUPITER, AND SATURN.
THEY'VE EVEN SENT SPACECRAFT PAST URANUS AND NEPTUNE
AND ALL THE WAY OUT OF OUR SOLAR SYSTEM.
I'M REFERRING, OF COURSE, TO THE VOYAGER MISSION.
NEVER HEARD OF THE VOYAGER MISSION?
WELL, YOU PROBABLY WEREN'T BORN YET WHEN IT WAS LAUNCHED.
THE TWIN SPACECRAFT, VOYAGER 1 AND 2,
WERE LAUNCHED IN 1977 TO STUDY JUPITER AND SATURN
BUT WERE ABLE TO CONTINUE THEIR MISSION WELL BEYOND THAT.
THEY'RE BOTH STILL GOING STRONG TODAY
BUT WAY, WAY, WAY FAR AWAY FROM US.
VOYAGER 2 IS NOW MORE THAN 85 ASTRONOMICAL UNITS
AWAY FROM EARTH,
AND VOYAGER 1 IS MORE THAN 105 ASTRONOMICAL UNITS AWAY.
OKAY, WAIT. WHAT'S AN ASTRONOMICAL UNIT?
WELL, BASICALLY, IT'S A UNIT OF MEASUREMENT
THAT HELPS US PUT THINGS IN PERSPECTIVE.
YOU ALL PROBABLY KNOW HOW FAR AWAY
THE SUN IS FROM EARTH, RIGHT?
ABOUT 150 MILLION KILOMETERS, OR ABOUT 93 MILLION MILES.
WELL, AN AU IS BASED ON THAT MEASUREMENT.
ONE AU IS THE DISTANCE FROM EARTH TO THE SUN.
SO RATHER THAN GETTING INTO ALL THOSE ZEROS,
YOU CAN KEEP IT MANAGEABLE USING AU.
LIKE, INSTEAD OF SAYING THAT VOYAGER 1
IS ABOUT 15.7 BILLION KILOMETERS AWAY FROM THE EARTH,
WE CAN SAY IT'S ABOUT 105 AUs.
STILL NOT SURE?
OKAY, LET'S LOOK AT IT LIKE THIS.
IF YOU WERE GOING TO GIVE SOMEONE DIRECTIONS
FROM YOUR SCHOOL TO YOUR HOUSE,
YOU WOULDN'T TELL THEM TO GO ABOUT 400,000 CENTIMETERS
AND THEN TAKE A RIGHT ON ELM, WOULD YOU?
AND GOING THE OTHER WAY, IF YOU WERE MEASURING, SAY,
YOUR WINDOWS FOR NEW CURTAINS, YOU WOULDN'T SAY
THEY'RE 5/10,000 OF A KILOMETER WIDE, WOULD YOU?
OF COURSE NOT. THAT WOULD BE RIDICULOUS.
YOU USE THE UNIT OF MEASUREMENT THAT MAKES THE MOST SENSE
AND ALLOWS OTHERS TO QUICKLY UNDERSTAND THE PROPORTIONS.
TO MEASURE HUGE DISTANCES IN SPACE,
ASTRONOMICAL UNITS JUST MAKE SENSE.
ALL RIGHT, THEN. MOVING ON.
AND SPEAKING OF MOVING, THERE'S ANOTHER NASA SPACECRAFT
THAT'S MAKING ITS WAY TO A VERY DISTANT DESTINATION.
IT'S CALLED NEW HORIZONS.
NOW, IT'S ACTUALLY ALREADY BEEN LAUNCHED.
IN FACT, IT WAS LAUNCHED ON JANUARY 19, 2006.
BUT IT'S NOT EVEN CLOSE TO ITS MAJOR POINTS OF INTEREST,
PLUTO AND THE KUIPER BELT.
THERE'S STILL A LONG ROAD AHEAD OF NEW HORIZONS.
HOW LONG?
WELL, WE CAUGHT UP WITH ALLEN LUNSFORD,
NASA TECHNOLOGIST ON THE NEW HORIZONS MISSION,
AND HE GAVE US A LITTLE INSIGHT
INTO THE TIMELINE OF THE PROJECT.
- IT TAKES A LONG TIME TO GET TO PLUTO.
IT'S 35 TIMES FURTHER FROM THE SUN
THAN THE EARTH IS, 35 AU.
TO PUT IT IN CONTEXT, JUPITER IS 5.5 AU AWAY.
SO IT'S A LOT FURTHER TO PLUTO.
IN FACT, WE LAUNCHED, AND WITHIN A YEAR AND A HALF,
WE'D FLOWN PAST JUPITER, AND IT'S STILL GOING TO TAKE
EIGHT MORE YEARS TO GET TO PLUTO.
IT WAS THE FASTEST SPACECRAFT EVER LAUNCHED FROM EARTH,
AND IT'S STILL GOING TO TAKE THAT MANY YEARS TO GET TO PLUTO.
AND WE DON'T HAVE THE FUEL TO SLOW DOWN,
SO WE JUST FLY PAST, AND AS WE'RE FLYING PAST,
WE TAKE ALL THE PICTURES WE CAN, STORE THEM ON BOARD,
AND THEN TAKE THE TIME AFTER WE'VE LEFT PLUTO
TO BROADCAST THEM, TRANSMIT THEM BACK TO EARTH
AND DO OUR ANALYSIS.
- SEE THERE?
SCIENTISTS REALLY DO TALK ABOUT AUs,
ASTRONOMICAL UNITS.
THAT MAKES SENSE NOW, RIGHT?
ANYWAY, SOMETHING ELSE HE MENTIONED
WAS HOW NEW HORIZONS HAS ALREADY PASSED JUPITER.
AND HOW IT DID SO IS ACTUALLY REALLY INTERESTING.
THEY USED A LITTLE SOMETHING CALLED GRAVITY ASSIST.
THIS TECHNIQUE HAS ALSO BEEN REFERRED TO
AS THE SLINGSHOT EFFECT,
AND IT'S BEEN USED BEFORE ON SEVERAL MISSIONS,
INCLUDING VOYAGER.
IT HELPS SAVE FUEL AND IS A BIG PART OF THE REASON
WHY THESE MISSIONS ARE ABLE TO SUCCEED.
BASICALLY, THE SPACECRAFT TAKES ADVANTAGE
OF THE GRAVITATIONAL PULL OF A BODY
TO SLIGHTLY ALTER ITS TRAJECTORY AND GAIN SPEED.
SO THE SPACECRAFT IS BEING PULLED
BY THE GRAVITY OF THE BODY,
BUT IT'S MOVING QUICKLY ENOUGH THAT IT DOESN'T ENTER ORBIT.
THE FORCE OF THE GRAVITY
IS ADDED TO THE SPACECRAFT'S VELOCITY,
INCREASING IT.
THE PLANETARY BODY IS ALSO AFFECTED.
BUT BECAUSE ITS MASS IS SO LARGE RELATIVE TO THE SPACECRAFT,
ITS CHANGE IN SPEED IS MINISCULE.
AS YOU CAN SEE IN THIS ANIMATION,
AS NEW HORIZONS PASSES JUPITER,
ITS TRAJECTORY CHANGES AND ITS SPEED INCREASES
AS IT SLINGSHOTS PAST.
NOW, BOTH OF THOSE FACTORS ARE IMPORTANT,
BECAUSE AS YOU CAN SEE, THEY HELP PUT NEW HORIZONS
ON THE RIGHT COURSE AND TIMELINE
TO PASS VERY CLOSELY BY PLUTO.
SEE, THIS ISN'T HAPPENING BY CHANCE,
AND IT'S NOT EASY.
ALL OF THIS HAS BEEN PLANNED.
RESEARCHERS HAD TO MAP OUT ALL OF THIS IN ADVANCE,
DOING ALL SORTS OF CALCULATIONS
ABOUT WHERE PLANETS WOULD BE WHEN,
THE NECESSARY VELOCITY FOR THE SPACECRAFT
TO ARRIVE AT THE RIGHT TIME,
THE DISTANCE NEW HORIZONS HAD TO BE FROM JUPITER
TO MAXIMIZE ITS INCREASE IN VELOCITY--
IT REALLY BOGGLES THE MIND.
AND I THOUGHT FIGURING OUT THE LOGISTICS
OF AN OVERNIGHT TRIP TO GRANDMA'S WAS COMPLICATED.
WELL, THAT'S IT FOR NOW.
UNTIL NEXT TIME, I'M JUSTIN TULLY.
THANKS FOR WATCHING "NASA LAUNCHPAD."