- GIANT CONES MADE
OF INFLATED KEVLAR TUBES STACKED TOGETHER
MAY SOMEDAY ALLOW CARGO OR EVEN PEOPLE
TO LAND ON OTHER PLANETS OR RETURN TO EARTH.
NASA CALLS THIS NEW SPACECRAFT TECHNOLOGY HIAD:
HYPERSONIC INFLATABLE AERODYNAMIC DECELERATORS.
BUT WHAT'S SO SPECIAL ABOUT HIAD?
FIND OUT MORE NEXT ON "REAL WORLD."
ENGINEERS MUST CONQUER THE CHALLENGES OF DESIGNING
AN INFLATABLE SPACECRAFT AND FLEXIBLE HEAT SHIELD
THAT CAN SURVIVE THE HIGH SPEED
AND HEAT OF ENTRY INTO AN ATMOSPHERE.
HIGH-TECH FLEXIBLE MATERIALS AND INFLATABLE STRUCTURES
ARE BEING DEVELOPED IN LABORATORIES RIGHT NOW.
BUT BEFORE THEY CAN BE USED TO TRAVEL TO MARS,
WE NEED TO DO SOME FLIGHT TESTING HERE ON EARTH.
THE INFLATABLE REENTRY VEHICLE EXPERIMENT,
OTHERWISE KNOWN AS IRVE-3,
PROVIDED A FLIGHT DEMONSTRATION OF THIS INFLATABLE CONCEPT.
- IRVE IS AN INFLATABLE REENTRY HEAT SHIELD
WHICH WE'RE TESTING IN THE EARTH'S ATMOSPHERE.
IN 2009, WE FLEW IRVE-2,
WHICH WAS VERY SUCCESSFUL
AND DEMONSTRATED THAT WE COULD INFLATE
A PACKED VEHICLE TO ITS FULL DIAMETER IN SPACE
AND THAT IT WOULD BE STABLE THROUGHOUT REENTRY.
NOW WE'RE TESTING IRVE-3,
WHICH IS THE FOLLOW-ON TO THE PREVIOUS MISSION.
AND IT WILL DEMONSTRATE HIGHER HEATING
USING A LARGER ROCKET TO LAUNCH A HEAVIER PAYLOAD,
INFLATE STILL BEHIND THE SAME
THREE-METER-DIAMETER HEAT SHIELD,
BUT WITH SIGNIFICANTLY HIGHER REENTRY HEATING
THAT IS RELEVANT TOWARD A REENTRY ON MARS.
- WHENEVER A SPACECRAFT
TRAVERSES AN ATMOSPHERE TO LAND ON A PLANETARY SURFACE,
WHETHER IT'S HERE ON EARTH
OR AT SOME OTHER PLACE, LIKE MARS,
THE SPACECRAFT MUST WITHSTAND TREMENDOUS FORCES
AND LAND SAFELY TO PROTECT ITS PRECIOUS CARGO.
AN INFLATABLE SPACECRAFT COULD ALLOW NASA TO SEND
MORE SCIENTIFIC INSTRUMENTS TO DISTANT WORLDS.
SINCE THE INFLATABLE EXPANDS
AFTER BEING PACKED INSIDE A ROCKET,
IT CAN DELIVER LARGER PAYLOADS.
THE INFLATABLE SPACECRAFT
IS DRAPED WITH A FLEXIBLE HEAT SHIELD.
THE PURPOSE OF THE HEAT SHIELD
IS TO SLOW DOWN THE SPACECRAFT AS IT ENTERS THE ATMOSPHERE
AND PROTECT THE SPACECRAFT
FROM HIGH TEMPERATURES EXPERIENCED DURING REENTRY.
SO WHY DOES SIZE MATTER?
WELL, THE LARGER THE TOTAL DIAMETER OF THE HEAT SHIELD,
THE GREATER THE DRAG FORCE THAT'S GENERATED.
YOU CAN THINK ABOUT DRAG AS THE RESISTANCE TO MOTION
AN OBJECT HAS AS IT PASSES THROUGH THE ATMOSPHERE.
SEVERAL FACTORS INFLUENCE DRAG:
THE SHAPE OF THE VEHICLE, THE DENSITY OF THE ATMOSPHERE.
BUT ONE FACTOR STANDS OUT,
MATHEMATICALLY SPEAKING.
DRAG IS DIRECTLY RELATED TO THE SURFACE AREA.
SO WHEN ALL OTHER FACTORS
THAT AFFECT THE AERODYNAMICS OF A SPACECRAFT REMAIN THE SAME,
IF YOU INCREASE THE DIAMETER TO DOUBLE THE SURFACE AREA,
YOU DOUBLE THE DRAG.
THIS INCREASED DRAG CAN THEN BE USED
TO SLOW DOWN THE SPACECRAFT,
ALLOWING IT TO LAND
WHERE NO SPACECRAFT HAD LANDED BEFORE.
RESEARCHERS AND ENGINEERS
APPLY MATH LIKE THIS IN THE MODELS AND TESTS,
BUT THEY CAN'T RELY SOLELY ON COMPUTER SIMULATIONS.
- THE COMPUTATIONAL MODELS ARE GOOD AT MODELING
EVERYTHING THAT WE HAVE A GOOD UNDERSTANDING OF.
FOR A NEW TECHNOLOGY,
WE REALLY NEED TO DO A FLIGHT EXPERIMENT
TO SHOW THAT THERE ARE NO UNKNOWNS OUT THERE
THAT ARE GOING TO BITE US
IF WE TRY TO USE THEM
ON A MUCH LARGER PAYLOAD.
- THE HIAD TEAM DEVELOPED MODELS,
CONDUCTED SIMULATIONS,
AND CONDUCTED TESTS
IN LABORATORIES ACROSS THE COUNTRY
AND THEN USED THESE
TO PREDICT HOW IRVE-3 WOULD PERFORM.
BUT ON THE GROUND,
YOU CAN'T SIMULTANEOUSLY MATCH
ALL ENVIRONMENTAL CONDITIONS
THAT A SPACECRAFT WILL EXPERIENCE
DURING AN ATMOSPHERIC FLIGHT.
SO THE NEXT STEP WAS TO ACTUALLY LAUNCH A HIAD
ON BOARD A SMALL ROCKET
TO DEMONSTRATE THE TECHNOLOGY WITH IRVE-3.
AND THE FLIGHT TEST WAS A GREAT SUCCESS.
ENGINEERS ARE NOW TAKING THE DATA AND KNOWLEDGE
THEY'VE GAINED FROM THE IRVE-3 FLIGHT
AND APPLYING IT
AS THEY LOOK AHEAD TO FUTURE HIAD APPLICATIONS.
WITH EACH GROUND TEST AND FLIGHT OPPORTUNITY,
THOSE MODELS ARE ANCHORED AND VALIDATED.
THIS PROVIDES CONFIDENCE AS WE PREPARE
FOR LARGER HIAD CAPABLE OF TRANSPORTING MORE CARGO.
- THIS IS ALL PART OF THE ENGINEERING DESIGN PROCESS.
IN ORDER TO GET A PAYLOAD
THAT MEETS THE MISSION REQUIREMENTS,
WE NEED TO FIRST COME UP WITH A DESIGN,
ANALYZE IT,
SEE HOW IT WILL DO
AGAINST THE EXPECTED ENVIRONMENTS,
AND THEN WE CONDUCT A SERIES OF TESTS
ON SUBSCALE HARDWARE
TO SHOW THAT EACH OF THOSE WILL WORK.
ONCE THE SYSTEM IS SHOWN TO WORK,
WE PUT IT ALL TOGETHER
AND GO AHEAD AND DO THE FLIGHT TEST.
- ENGINEERS HAVE BEEN MODIFYING THE SAME BASIC TECHNOLOGIES
TO EVERY NASA MISSION TO MARS SINCE VIKING.
BUT WITH HIAD,
NASA ENGINEERS ARE REALLY HEATING THINGS UP
WITH INFLATABLE TECHNOLOGIES
THAT CAN CHANGE THE WAY WE EXPLORE OTHER WORLDS.
SEE YOU NEXT TIME ON "REAL WORLD."