amber straughn is an astrophysicist on the project. >> amber straughn: telescopes really are time machinesthe past. and the reason for that is just due to the nature of how light travels. light from the sun takes about eight minutes to get to the earth. so, we're seeing the sun as it was eight minutes ago. and you can sort of think about stepping that further out into the universe. >> pelley: so, when we walk out under the stars, and look above us, we're not seeing the stars as they are today. we're seeing them as they were perhaps millions of years ago. >> straughn: absolutely. >> pelley: because it took that long for the light to reach the earth. >> straughn: yes, for sure. >> pelley: how much do we know about the universe? >> straughn: everything we know about, everything we can see, me and you, everything on the planet, all the hundreds of billions of other galaxies-- all of that only makes up about 5% of the universe. the rest of it, that other 95%, we have no idea what it is. >> pelley: that 95%, the unknown, is all around us, like a ghost. nearly all the cosmos is made up of what ph

astro physicist amber straughn hopes webb's discoveries will fill in in blanks. >> we hopefully willbe able to see the galaxies for the first time. >> reporter: the gold plated mirror will alline to create one mirror, 21 feet across, six times larger than the one on the hubble space telescope. for more than three decades, hubble has given us stunning humbling views of the universe. but webb will search for heat >> we aroking for thes. the telt cold, it will actually glow brighter than the objoro blo th, engineers designed a first of its kind sun shield, the size of a tennis court. it's five layers will keep the telescope side more than 600 degrees colder than the sun facing side. >> this material here is about 2 thousandths of an inch thick. >> reporter: once in space, webb will carefully unfold and rebuild itself like robotic origami. project manager bill oaks. >> the complexity, the deployment, the materials has never been tried by a n.a.s.a. mission before. >> reporter: if any one of 344 parts fail, the entire mission could be jeopardized. it all has to work. >> it's got to be pre

astrophysicist amber straughn hopes webb's discoveries will fill in the blanks. >> we hopefully wille able to see those first galaxies for the very first time. and of course, galaxies are the homes of stars, and stars are the homes of planets, and planets of course are the homes of life. and so this telescope is our going to be next giant leap in our search for habitable planets in our galaxy. >> reporter: webb's 18 hexagonal gold-plated mirrors will align to create one giant mirror. it's 21 feet across, six times larger than the one on the hubble space telescope. for more than three decades, hubble has given us stunning, humbling views of the universe. but, webb will be a major upgrade. like a night vision camera, this infrared telescope will search for heat signatures of the very first light after the big bang. >> we are looking for the of the faintest objects, if the telescope doesn't get cold then it will actually glow brighter than the objects we're looking for. >> reporter: to block the sun's heat from blinding webb, engineers designed a first of its kind sun shield, the size o

amber straughn is the deputy project scientist for webb communications. >> everything glows in infraredu and i are glowing in infrared. and a telescope, and even in low earth orbit, would glow in infrared. and so, we need to have this telescope out in deep space, so it gets very, very cold, so, in essence, it's not glowing and seeing itself. it has to be cold, so it can see the infrared signals from the distant universe. >> reporter: they have tested the telescope every which way they could imagine. they have shaken it, and exposed it to loud noise to mimic a launch. and, they turned it on in a giant "apollo"-era thermal vacuum chamber at the johnson space center in houston. the hubble experience looms like a nightmare. it was infamously launched with a flawed mirror, rendering the telescope terribly near-sighted, until it was corrected three years later, during the first hubble repair mission. greg robinson is the webb program director. do you feel pretty confident this telescope is not going to be flawed from the outset? >> we try to test exactly the way it's going to be used in this