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welcome to future path I'm a Mariko for

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Astari the director of External Affairs

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at the NASA Lewis Research Center in

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this series we are exploring research

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and technology programs that may affect

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our lives this show deals with the

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present and the future in a little while

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we'll see how an advanced propeller

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aircraft engine now under test may

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replace conventional jet engines but

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first let's take a look at the space

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station here at Lois we have had an

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ongoing program to design power systems

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for future spacecraft before Lewis began

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to work on a power system for the space

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station however many years of research

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went by throughout the 30-year history

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of space exploration there has been an

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evolution in our understanding and use

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of space

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we began with exploration pioneering

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kind of missions we've demonstrated some

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initial space operational capability

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with the shuttle we now want to make

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space a place where we live and work

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permanently so space station we believe

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is the next logical step in that

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evolutionary process the next logical

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step we have visited space for short

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periods we now have the capability and

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resources to make it a place to go to

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stay permanently a place where we go to

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work and to do useful tasks a space

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station is a logical place in which to

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do this

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the main horizontal keel will have solar

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powered electrical generating systems

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and pressurize crew and laboratory

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modules the space station is being

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designed to serve a variety of users

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many experimenters have been identified

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these will be earth viewing space

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viewing experiments many microgravity

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experiments Space Station will be used

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for assembly of large structures

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servicing of satellites and other

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payloads and as a transportation node in

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the sense that payloads would be taken

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off of the space shuttle and put on to

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some other rocket to go into

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interplanetary space or to high Earth

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orbit space station will be a research

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laboratory to conduct science and to

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develop new technologies a permanent

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Observatory enabling us to look down at

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earth and up at the stars the station

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will be a servicing manufacturing and

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assembly plant as well as a storage

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depot and a staging base there are many

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other uses the bottom line is that space

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station will be a multi-purpose facility

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very much unlike the spacecraft that

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nASA has designed in the past which were

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designed for essentially one mission

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space station will be very different it

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will be multi-purpose and it will be

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very long-lived compared with previous

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spacecraft in the sense that space

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station is designed for approximately a

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30-year lifetime you contrast that with

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single purpose satellites which might be

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designed for a few years at most the

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role of Lewis Research Center in the

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space station program is to design the

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electrical power generating conditioning

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and storage systems power the use of

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power for civilization is a measure of

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its development if you chart the usage

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of power on earth you find that the more

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advanced societies use more and more

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electric power the less advanced you are

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the less you use in space we've been

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absolutely primitive in the first 25

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years of the space program scarcely

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using more than 10 kilowatts put that in

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perspective your house uses about 25

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kilowatts so we're limited in what we

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can do

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and that means we can't really flex our

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muscles in space we can't utilize it we

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can't understand it well so we're power

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poor and so we can't explore power is

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vital the space station without power

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the station could not work other space

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missions use a small amount of power in

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comparison to space stations needs

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communication satellites use up to about

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10 kilowatts of power previously the

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largest user of power in near space was

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Skylab it used about 15 kilowatts of

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electricity space station may use more

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than 20 times that or nearly 300

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kilowatts to make that much electricity

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space station will eventually rely on

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hybrid or combination of both solar

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cells and a solar dynamic system the

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system to be used first is a solar cell

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system solar cells in large panels or

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solar arrays collect sunshine and

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convert it directly into electricity the

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hardware to be launched first by the

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shuttle will be solar panels they've

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been used to power spacecraft now

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throughout the history of the space

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program and we have great confidence

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that they will work that we will be able

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to manufacture test and verify their

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performance to a very high level of

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confidence early solar array panels are

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about 7% efficient but now new improved

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solar arrays run at about 10% efficiency

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solar panels have a drawback to produce

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about 300 kilowatts 30,000 square feet

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of panels are needed that's a lot at

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first to complete solar panels will be

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orbited for Space Station each unit will

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be about 110 feet long by 33 feet wide

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another problem created by the large

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size of the panel's

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is atmospheric drag even though space

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station will orbit at about 250 miles

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there are enough atoms of air at that

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altitude to impact on the panel's and

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cause the station to slow down ever

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so slightly so the station must be

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periodically boosted back into its

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original orbit NASA is designing a

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system with a smaller area to reduce

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atmospheric drag this system is the

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solar dynamic system solar dynamic

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system uses a concentrating mirror to

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collect and focus the sun's energy into

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a receiver that accepts that energy in

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the form of heat that's very different

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than solar cells which converts sunlight

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directly into electricity solar dynamic

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systems operate on heat use that heat to

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heat a fluid that runs through a turbine

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causing it to rotate the turbine of

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course is attached to a generator which

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actually converts the mechanical energy

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of rotation into electrical energy and

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that circulating fluid is then reused in

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a closed system so solar dynamic systems

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take sunlight convert it to heat that is

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transformed into mechanical energy and

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then finally into electrical energy that

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sounds like a complex process but the

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overall system efficiency there is

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greater than it is for photovoltaic

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devices besides having a smaller drag

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area the solar dynamic system is more

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than 15 percent efficient and NASA is

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looking at other systems which are more

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than 30 percent efficient they use

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different engines to drive generators

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but what do you do if there's no

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sunlight communication satellites orbit

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at an altitude of 22,000 miles these

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satellites rely on solar cells and

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storage batteries for power batteries

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supply electricity to the craft when it

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is in Earth's shadow at 22,000 miles

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those satellites rarely pass into the

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shadow of Earth in low-earth orbit space

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station will be in the shadow of earth

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for about half of each 90-minute orbit

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the initial space station relying

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exclusively on solar cells will require

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much larger batteries than previously

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used in space but as solar

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amic power systems are added energy

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storage will be a different matter

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altogether

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in the case of the solar dynamic system

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that energy is stored in the form of

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heat the leading contender for storing

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that energy that heat energy now is some

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type of salt a phase change material

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that converts from a solid to a liquid

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and by virtue of doing that is able to

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store much greater amounts of energy

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these salts or phase change materials

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are not like common table salt the

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special salts melt at a very high

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temperature when space station passes

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into the Earth's shadow sunlight will no

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longer be focused on to the receiving

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cavity of the solar mirror the salts

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will slowly cool and change from a

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liquid to a solid giving off large

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space station power systems will make a

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lot of electricity initially more than

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75 kilowatts and more later how will all

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this electricity be used probably the

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users will be the largest consumers of

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power there is a class of experiments

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called materials processing that are

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estimating their needs and the tens of

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kilowatts by far in a way that will be

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the single largest user of power

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we also lump power into another category

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called housekeeping by this we mean

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electrical energy required to operate

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the environmental control and life

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support system for regenerating the air

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and water on board the space station

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housekeeping also includes lights

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preparing food in the galley

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entertainment devices and so forth

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personal care devices that the

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astronauts might use and communications

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and computer systems all of that we lump

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into housekeeping power and it will be

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not as large a user of electrical energy

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but it since we lump so much into that

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single category it looks like a big

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number the shuttle will first launch

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space station elements

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the mid-1990s shuttle will be used in

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the assembly and check out of the

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station a number of launches will be

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needed and there will be various phases

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of capability that the station will go

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through it will be unmanned at first

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then mant ended within a year and a half

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beyond that the station is to be

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permanently manned the ultimate benefit

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of space station to mankind will be to

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extend man's capability to explore the

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solar system space station will provide

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the necessary first step for future

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manned missions in space a permanent

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lunar base a manned mission to Mars a

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manned survey of the asteroids space

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station will enable the staging of

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future unmanned missions to the planets

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with the possibility of sample returns

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but most importantly Space Station will

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now let's turn from the space station to

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a story about how propellers may again

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be back on passenger planes in the late

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1950s jet aircraft entered into

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commercial service and essentially

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replaced the slower but more efficient

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propeller driven aircraft then in the

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late 1973 the oil embargo hit NASA was

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mandated to explore all technologies

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that could significantly reduce

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commercial aircraft fuel consumption the

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Lewis Research Center responded with the

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advanced turboprop program what might

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look like a step backwards is actually

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two giant steps forward on the future

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since 1941 the Lewis Research Center has

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developed an international reputation

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for its research on jet propulsion

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systems however in 1977 the researchers

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at Louis began to take a new look at the

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propeller their challenge was to combine

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the efficiency of the propeller with the

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power of the turbine engine what has

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evolved is ATP the advanced turboprop

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project Keith severs manager of the NASA

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advanced turboprop project office at the

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Lewis Research Center back after World

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War two jets for the thing the coming

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thing her powers were very efficient in

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those days but they couldn't go fast it

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couldn't go to high altitudes and quite

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frankly they were not jazzy like jet

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engines and which gave way then to

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turbofan engines and high bypass ratio

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engines and when fuel was chief people

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didn't worry much about it ten cents a

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gallon as long as they get speed high

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altitude capability which the air

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transport system required propellers

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just kind of withered on the vine for 20

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or 30 years the Arab oil embargo of the

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early 70s not only hit American

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consumers at the corner gas station but

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was also reflected at the airline ticket

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counter due to the soaring price of jet

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fuel in 1973 the price of a gallon of

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jet fuel was 12 cents and represented

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one-quarter of the direct operating cost

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of the jet in 1981 the cost of jet fuel

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was over a dollar eight cents a gallon

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with the rising fuel prices a fuel

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efficient propeller engine again became

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the object of an aeronautical propulsion

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research effort

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the researchers objectives were to

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develop a powerplant that would be fuel

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efficient dew point eight mach cruise at

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35,000 feet operate at a reduced noise

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level well these propellers look a lot

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different there are very highly swept

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they're very thin compared to old

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propellers

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and the thing that hits you first is

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their eight to ten blades on these would

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rather than three or four is that you've

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00:15:30,350 --> 00:15:28,320
been accustomed to in the past and what

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the sweep doesn't in the propeller and a

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fitness is is to reduce the drag losses

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at the higher tip speeds and higher Mach

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numbers also helps to reduce the source

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noise of the propellers the higher

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blade count and we've loaded these

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blades up much higher than old fellers

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so we get a lot more power at a lot

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smaller diameter and this saves weight

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on the propeller and I say it's weight

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on the engine and it also packages

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better on the aircraft earlier two turbo

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props were limited both in horsepower

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and in flight speed mainly because of

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the compressibility effects that occur

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at the propeller tips with the recent

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advances in computer design technology

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we are now able to optimize the blade

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shape to minimize the compressibility

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effects occurring at the blade tips

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allowing the planes to fly faster up to

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six hundred miles an hour and at higher

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altitudes up to thirty five thousand

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feet as you approach the speed of sound

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you run into a problem where the

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apparent pressure that you're trying to

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push through suddenly takes a quantum

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leap and because the blades are very

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large in diameter to thirteen feet in

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diameter the tip speed is upwards of 800

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feet per second which is just under Mach

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00:17:08,240 --> 00:17:04,020
1 or the speed of sound as you try to

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00:17:10,250 --> 00:17:08,250
push through that Mach 1 range you run

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into this compressibility factor it's

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almost like running into a brick wall

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with the blade blade construction is now

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a composite type arrangement where you

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have a metallic leading edge such as

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aluminum and a graphite epoxy resign'd

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internal construction that allows the

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blades to be very lightweight and

357
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because they're lighter weight minimizes

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the centrifugal stresses that occur when

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the propeller system is

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dated at 12,000 rpm ultimate goal is to

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save fuel commercial aircraft and also

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military aircraft were it can be applied

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and this fuel saving is very dramatic

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compared to the fuel burn that aircraft

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00:17:54,200 --> 00:17:50,789
have today such as a 727 737 that type

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00:17:56,029 --> 00:17:54,210
of air cream aircraft a prop van driven

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00:17:59,060 --> 00:17:56,039
airplane can do the same mission that

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like forty to fifty percent of the fuel

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that they use today if you look at just

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the u.s. fleet existing today for medium

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to short range aircraft I'm talking 727

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00:18:15,230 --> 00:18:13,200
737s dc9 md-80s those aircraft in a

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00:18:18,649 --> 00:18:15,240
typical year burn about five billion

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00:18:21,799 --> 00:18:18,659
gallons of fuel if these aircraft were

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equipped with pop fans they could do the

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same mission they're dirty today and

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save two to two and a half billion

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00:18:41,750 --> 00:18:39,500
propeller-driven airplanes have

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traditionally been noisy advanced

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00:18:46,039 --> 00:18:44,280
turboprop researchers are tackling the

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problem of trying to build a turboprop

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00:18:51,770 --> 00:18:48,630
to rival the relative quiet and

383
00:18:53,780 --> 00:18:51,780
smoothness of the jet well we've had to

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look at the entire aircraft as a system

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we didn't look just at sticking a new

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widget call of profiting on them better

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00:19:01,820 --> 00:18:59,850
look at what to do to do to the rest of

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the aircraft and particularly we're

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00:19:05,840 --> 00:19:04,080
concern about passenger comfort it

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00:19:08,390 --> 00:19:05,850
doesn't matter how much fuel was saved

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00:19:14,450 --> 00:19:08,400
if the people don't like it or they're

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00:19:17,150 --> 00:19:14,460
uncomfortable sound vibration so part of

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00:19:18,650 --> 00:19:17,160
our project goal is to to make sure that

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people have the same comfort that

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00:19:23,419 --> 00:19:20,160
they're used to on today's wide-body

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00:19:25,100 --> 00:19:23,429
aircraft in addition we're concerned

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00:19:26,480 --> 00:19:25,110
about community noise these things are

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allowed and we have to provide the

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00:19:33,570 --> 00:19:28,540
technology so we think it will

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00:19:33,570 --> 00:19:33,580
listing for 37 states we regulate

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00:19:33,580 --> 00:19:47,490
by around airports and communities

402
00:19:50,620 --> 00:19:49,510
most of the time we really don't even

403
00:19:54,070 --> 00:19:50,630
know what's running inside the cockpit

404
00:19:56,380 --> 00:19:54,080
it's that quiet and we're only what 15

405
00:19:58,720 --> 00:19:56,390
feet away from after several years of

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00:20:00,880 --> 00:19:58,730
wind tunnel and static engine testing a

407
00:20:04,630 --> 00:20:00,890
full flight test of the advanced

408
00:20:07,659 --> 00:20:04,640
propeller system was held on May 19 1987

409
00:20:10,419 --> 00:20:07,669
at Lockheed Georgia company in Marietta

410
00:20:13,510 --> 00:20:10,429
Georgia so far operation has been very

411
00:20:16,110 --> 00:20:13,520
good everything is about as predicted

412
00:20:17,760 --> 00:20:16,120
that the engineers had predicted

413
00:20:20,610 --> 00:20:17,770
from their initial assessment of the

414
00:20:24,330 --> 00:20:20,620
program we haven't really had any big

415
00:20:27,360 --> 00:20:24,340
surprises I should say when you pull the

416
00:20:29,519 --> 00:20:27,370
prop fan in and add power to it the

417
00:20:31,019 --> 00:20:29,529
pilot really knows it but there again

418
00:20:32,940 --> 00:20:31,029
this airplane wasn't really designed to

419
00:20:34,080 --> 00:20:32,950
fly with an engine out on a on the left

420
00:20:37,169 --> 00:20:34,090
wing

421
00:20:38,760 --> 00:20:37,179
but again what our engineers predicted

422
00:20:40,860 --> 00:20:38,770
is pretty much what's happening with the

423
00:20:42,960 --> 00:20:40,870
airplane so I'd have to say so far it

424
00:20:45,810 --> 00:20:42,970
looks good so far it looks very good if

425
00:20:48,180 --> 00:20:45,820
all goes to plan prop fans will probably

426
00:20:51,810 --> 00:20:48,190
be fitted on short to medium range

427
00:20:54,120 --> 00:20:51,820
aircraft we hope to have as a part of

428
00:20:57,810 --> 00:20:54,130
the project goal to have the technology

429
00:21:00,570 --> 00:20:57,820
in hand by the end of 1980s so that

430
00:21:02,820 --> 00:21:00,580
industry the engine people the aircraft

431
00:21:05,340 --> 00:21:02,830
people can make marketing decisions

432
00:21:07,590 --> 00:21:05,350
because it's a involves a lot of private

433
00:21:10,320 --> 00:21:07,600
capital that's a make sure breaks

434
00:21:13,100 --> 00:21:10,330
they're companies so the way things are

435
00:21:16,320 --> 00:21:13,110
proceeding right now it looks like

436
00:21:18,120 --> 00:21:16,330
Boeing and McDonnell Douglas are aiming

437
00:21:21,480 --> 00:21:18,130
for new aircraft injuries or with the

438
00:21:27,540 --> 00:21:21,490
prop fans and say the 1991 92 93

439
00:21:32,020 --> 00:21:30,190
the advanced turboprop program that you

440
00:21:33,790 --> 00:21:32,030
just saw will help maintain the US

441
00:21:36,220 --> 00:21:33,800
aircraft industry in a dominant world

442
00:21:38,230 --> 00:21:36,230
leadership position well we've nearly

443
00:21:40,330 --> 00:21:38,240
come to the end of our show but before

444
00:21:43,060 --> 00:21:40,340
we go let's watch this NASA Lewis

445
00:21:44,170 --> 00:21:43,070
Research Center overview this segment

446
00:21:45,850 --> 00:21:44,180
will show you some of the high-tech

447
00:21:47,890 --> 00:21:45,860
facilities and people who make it

448
00:21:50,560 --> 00:21:47,900
possible for Louis to accomplish its

449
00:24:33,009 --> 00:21:50,570
mission to develop advanced technology

450
00:24:37,369 --> 00:24:35,149
thank you for spending some time with us

451
00:24:39,019 --> 00:24:37,379
please stop by and see the many displays

452
00:24:41,450 --> 00:24:39,029
and programs at the Visitor Center here

453
00:24:43,489 --> 00:24:41,460
at Lois we are located near Hopkins

454
00:24:45,409 --> 00:24:43,499
International Airport in Cleveland Ohio

455
00:24:48,440 --> 00:24:45,419
admission is free and we are open every