JWST Interview with NASA Goddard | James Webb Space Telescope

hello and welcome to another episode the space update part of the fantastic total space network coming up on today's show we're talking with dr jonathan gardner from nasa goddard uh talking about jim's website space telescope and a whole lot more i'm your host ryan and joining me today is i'm mikko the host of deep dive fridays i'm rich lb co-host of becoming multi-planetary and i am kage also co-host of becoming multi-planetary thanks for joining us guys and as always uh we've got uh dr jonathan gardner here with us so we just briefly like to introduce yourself uh jonathan sure thank you for having me i'm jonathan gardner i am the deputy senior project scientist for the james webb space telescope at nasa's goddard space flight center in maryland in the united states i am also i have another title i'm the chief of the observational cosmology laboratory at goddard fantastic to be here thank you for popping along uh absolutely fantastic having you on the show uh obviously before we get in get into it um some of our viewers might not have heard about james webb's telescope do you want to give us a brief brief overview into the james webb telescope and maybe lead on to what you're hoping to achieve with it absolutely yes the web is the successor to the hubble space telescope one of the most successful telescopes in the history of our planet and web has been uh in production for almost 20 years and we're gearing up for launch later this year now it's going to be a large large telescope bigger than hubble it's the successor to hubble and um the spitzer space telescope another infrared telescope and hubble works in visible light and with web we're going to extend that into the infrared redder light than we can see it's going to be a very cold telescope 225 degrees below zero celsius and it's a an international project of nasa and the european and canadian space agencies so that's kind of the top level view of what it is and as for what it will do i'll be happy to talk in what much more detail about that but uh that basically it's an observatory we will point it at stars and galaxies and planets in the sky and gather the data and learn a whole lot more about what we're looking at with um it's a general purpose observatory instead of being an experiment doing one thing it's multi-capable and will be able to address almost every aspect of astronomy fantastic um just to essentially start from the game beginning leading on from that what were the biggest challenges in the initial design stage if you like um with the james webb space telescope in terms of hardware and what you want to study and achieve and also were there any trade-offs in regards to that in terms of ways you couldn't put something in there that you really wanted because it was too heavy and stuff like that sure so in the mid-1990s about five years after hubble was launched in 1990 uh astronomers and nasa started to think about what do we want to have to come next what's the success are going to look like and it was quickly realized that we didn't just want a carbon copy replacement because that would do the same things that hubble is doing we wanted to take the science beyond and in one way in particular in the early days uh hubble could see um very far away and very far back towards the the beginning of the universe and looked at looking at galaxies um that uh that were existing in the very early universe we realized that some of those galaxies already were old and we needed to go further back and further away and in order to do that we needed a telescope that was bigger than hubble so that's the one thing about web that's that's very different from hubble it's bigger so hovel has a 2.4 meter diameter primary mirror and web will be six and a half meters in diameter yeah the next thing is that um we astronomers decided that they wanted to push into the infrared uh with webb further uh further beyond the um the the visible light that we can see now hubble can work in the ultraviolet and visible light and a little bit into the infrared but astronomers wanted to go further into the infrared and that means it had to be cold so those were the two big design uh characteristics that the engineers then sat down and started thinking how do we how do we make a telescope that's bigger than hubble and how do we let it to be let it cool down to uh as i said 225 degrees below zero so to make it bigger we had to have a foldable telescope the six and a half meter diameter mirror has to fit inside a five meter diameter rocket so we had to fold the whole thing up it had to be light weighted so the the web is actually only about half of the mass of hubble but a much bigger telescope and that led us to having a segmented mirror design so if you can see if you look at the mirror of web you see 18 hexagons put together into the primary mirror and the um in comparison hubble is is a single piece of glass uh then so so web had to be foldable and um it's it's a lower lower mass and then another trade is that in order for it to cool to these very cold cryogenic temperatures we had to get it away from the earth so hubble's in what's called low earth orbit about uh it orbits the earth every 90 minutes and when it goes on the daytime side of the of the earth the sunlight is shining on it and the earth light is reflected back onto the telescope it goes behind the earth each orbit but uh and starts to cool off but we wanted a telescope that would be cold all the time and so webb is going to be in a special orbit that is uh 1.5 million kilometers away from the earth called the second lagrange point and so those are the the basic design criteria of um of web bigger than hubble and cold so it's sitting behind a giant tennis court size sun shield allowing the the heat of the telescope to just radiate into deep space the telescope is always on the dark side of this sun shield and always in uh shielded from both the sunlight and the earth light so those were the challenges and that's that's makes for a very complicated space observatory and that's why we've taken 20 years to build it we're almost there almost almost um i know you had a storm during the testing i heard that on the news and everything a sort of emergency delivery of liquid nitrogen during the testing um i know that's a called running the telescope and everything yeah absolutely um the the testing of the telescope and the instruments um was done in a vacuum chamber uh what we call a thermal vacuum chamber or cryogenic vacuum chamber so we put it into this giant giant chamber at the johnson space center in houston texas pumped out all of the air cooled it down using liquid helium down to its operating temperature and uh that was an interesting chamber because that was actually that vacuum chamber was built for apollo and the the lunar astronauts the the apollo astronauts practiced walking uh in their spacesuits inside this same chamber that that webb went into uh that was a couple of years ago and it uh we got hit by hurricane harvey which dumped 51 inches of rain onto the houston area during that time a lot of heroism by the people who were running the test i mean some of them had their houses flooding and they were in there working on the uh the webb telescope testing and at one point it was running the risk of running out of the cryogens running out of the liquid nitrogen and some people got on the phone with the company president um and got a special delivery to the houston area uh to get that in there so we wouldn't have to warm up the telescope and and stop the test that has took about three months it took a month to cool down to its operating temperature a month worth of testing and then another month to warm up put it through its faces and it it it all works so it's worth it in the end and that uh origami style for the mirror is quite quite unique um what apart from making it fit inside the payload fair of the rocket and everything like that what inspired that design did the mirrors just need to be more flexible rather than rigid one-leg hubble so the mirrors itself there are 18 mirror segments each one is 1.3 meters um from the flat to flat on the hexagon um we it's a hexagon design because that's the way tiling works um basically the way optics of telescopes work is that it's good to be close to having a circular telescope you end up with a sharper uh sharper image of a of a star with the circular telescope so the the geometry is simply how to make something pretty close to a circle out of 18 different segments now each of those mirror segments as i said is is 1.3 meters from flat to flat on the hexagon it's made of beryllium is a very lightweight very stiff metal and the uh the the big advantage of beryllium for webb is that um when you get it down to the operating temperature it doesn't change its shape if the temperature varies by uh by a degree or two there will be a temperature gradient across the face of the primary mirror going from about 30 degrees above absolute zero to about 50 degrees above absolute zero uh at the at the top point uh with beryllium it doesn't change shape um we also lightweighted it so the back of the mirror segments is all um etched out so there's this kind of honeycomb structure and then the front of the mirror the reflective part is gold gold is very highly reflective in the infrared and uh um so that's that's what leads to the the gold color of the mirror now you asked about um how it compares to hubble there is uh one thing we had to give up when we coated the mirrors in gold gold will reflect gold colored light that's why it looks gold it'll reflect red light and it reflects infrared very well but it doesn't reflect the blue light and it doesn't reflect the ultraviolet so hubble has been an ultraviolet and visible light telescope there is some overlap in the light that it that you can see but i'll tell you what astronomers really are looking forward to since hubble is still going strong is using the two telescopes together so uh we're we're um planning to use web to follow up all of the discoveries that hubble has made but we wanted to go the other way as well we learned something about a star or a galaxy or a planet in the infrared and we'll say oh i wonder what that looks like in the ultraviolet and so we'll still have hubble um as long as it keeps going we'll be using the two telescopes together fantastic fantastic um do you wanna come in cargill uh rich with a quick question or anything yeah absolutely um so can you walk us through the the process of preparing uh james webb for its mission so uh from from the launch until uh the last of its uh 30-day deployment um can you just walk us through what that looks like sure um should we run the video that shows the deployment sequence is that what you'd like to do after launch the web will be launched from south america on an ariane 5 rocket and we get rid of the rocket we get rid of the fairing and then we start to do all of this unfolding first thing to come out is the solar panels to provide power and a communication antenna and then we will start to fold out the five layer uh sun shield that will protect the telescope from the sunlight and from the earth light you can see in the video the two uh the two pallets have been folded out there's a deployable tower which will separate the sun shield and the spacecraft from the telescope and then we will start to un unwrap and uh fold out the five layer sun shield the membranes on the sunshield are called kapton it's kind of a plastic material fairly thin shiny on one side so that it reflects the sunlight away and there are five layers each separated by almost half a meter to allow the heat to escape in between the five layers the uh last deployments then are the secondary mirror comes out on its three-legged spider and the two side wings of the primary mirror are folded out that's what we just saw is a process that will take place about the first two to three weeks after launch we'll have all of the major deployments done but then we need to uh turn 18 individual mirrors into one common optical surface uh this is called phasing the mirror and that actually will take three months it's a three month long process so when we uh when we get all of the deployments done and we move the the mirrors off of their kind of stowed configuration we'll point the telescope at a at a bright star and um once it's cooled down enough that we can turn on the the near infrared camera one of the main imaging cameras we'll take a picture and we will see 18 out of focus images of that bright star so we then start to move each of the 18 mirror segments so that they line up together so they're all pointed at the same place and then we have to measure the the phase or the the whether the the light that's hitting the mirror is being reflected back with the same wavelengths um as the other mirror segments that's a very long complicated process of measuring whether the whether the lights all all phased up it's also an iterative process so we'll go through it we'll get a pretty good picture image then we'll undo it and redo it again and then we'll start once we got it perfect in one place in the field of view one part of the the picture we will then extend that to the rest of that camera the near-infrared camera and once we can turn on the other three cameras we'll make sure that they are phased up in focus as well so that takes us to about four months after launch and then we need to check out all of the instruments there are four scientific instruments i've mentioned the near-infrared camera we have a near-infrared spectrograph a spectrograph uh as as somebody puts it it puts the fizz in astrophysics going from astronomy pictures to astrophysics of really understanding what we're looking at um so the spectrograph breaks up the light and you can see the components the the alchemical elements that make up what you're looking at it also allows us to measure velocities through the the doppler shift so that's the near-infrared spectrograph and that's actually a contribution from the european space agency we also have the uh mid infrared instrument which is the longest wavelengths that webb can see that's a that's a camera that does both imaging and spectroscopy and will be very powerful at studying the formation of stars and planetary systems within our own galaxy and then finally the fourth instrument was provided by the canadian space agency and that's a specialized camera designed to study a particular kind of extrasolar planet or extra exoplanet as well as doing some uh again some specialized things with uh planetary dust discs and uh distant galaxies um so after launch we've got one month to do the major deployments and to cool down the telescope to the point where we can we can start using the instruments three months to phase up the mirrors get the mirror to work perfectly as a single optical surface and two months to check out the instruments and then at launch plus six months we'll start to do the science that people are all excited about amazing thank you um and there's a there's a very complicated dance to uh this this whole thing uh to get from uh leaving earth's uh orbits to getting to the l2 lagrange point where it'll finally rest all the various puzzle pieces that have to uh fall into place in order to basically assemble itself um so what what happens if there is any uh any difficulties with these uh with these puzzle pieces unfolding and assembling if there's any failures with those things like for example a tear in uh one of those sun shields what kind of recovery options are in place well so one of the reasons why it's taken so long to build this telescope is because of the process of making a major space telescope and observatory like this is also iterative what we do is we will build a small component like for example a detector to go into an instrument and we'll test it and make sure that it it works and we'll shake it and blast it with sound as if it were being launched and then we'll make sure that it still works then we put that detector into an instrument into a camera assemble the camera together and we do the testing again we put it into a vacuum chamber to make sure it works we will shake it and and plastic with sound vibration and acoustic testing at the instrument level we put the instruments together into the compartment behind the telescope we test it again we assemble the telescope with the instruments and that was the big test that we did at um the johnson space center in houston that i mentioned earlier testing testing it again and then finally now we're in the process we have assembled the telescope together with the spacecraft and sunshield we put that whole thing through a simulated launch um with the vibration and acoustic uh sound blasting um uh and and did a final deployment test doing the the testing the the deployment of the sun shield and the um the telescope we're now having done that test we're now in the process of the final assembly final uh folding it up getting it into the launch configuration so that we can ship it to the launch site later this summer all of that testing is designed to is a process that nasa has worked out over the last 50 years or 60 years of of the space program it's a process that we've worked out so to make sure that things will work when they get into space nothing's going to to make sure that nothing's going to break due to the vibrations or the sound of the rocket because we've already tested that on the ground things will work in in vacuum and they'll work in the uh at the temperatures that they will see in space again because we've tested that in vacuum chambers in the ground on the ground so yeah it's a it's a complicated process a long process i will say that during the deployments we will be in constant communication with the spacecraft of course um and we've got telemetry telling us where things are how things have gone if we push out the booms to pull out the sun shield and it doesn't look like it's right we can back it up and try again um but at the end of the day you know so we'll we'll know what we'll know what's um where it is at every point and uh we'll be able to uh to to try again if something's not working um there is uh also some redundancy all of the electronics have dual electronics so if side a has a component failure or something we can switch to side b no we always aim at no single point failures it would take two failures to actually uh yeah a really bad day so um so that's uh that's the plan and um it's it's why things uh it's it's why space programs are are complicated and expensive because we have to do all of this testing the work and i'm sure it'll be i'll go smoothly on on the day hopefully um last year discovery of a jupiter-sized planet orbiting a white dwarf star caused quite a list among the community um i know we're probably going to see a lot more of uh studies with the james webb telescope studying dwarf stars and everything but absolutely incredible discovery uh will that be on the top 10 list of things to start looking for sure so uh exoplanets actually are something that um was not considered 20 years ago when we first started building or first started designing the web telescope exoplanets were still kind of new we we knew about a few dozen but we didn't know a whole lot about them whereas now we've got uh hundreds thousands of exoplanets that we have and we have a a smaller mission nasa's got a smaller mission called the transiting exoplanet survey satellite um tess and tess is designed from the start was designed to find good targets for webb to follow up it's kind of a i mean it's a it's a wonderful science mission and it's in its own but it's also to some extent a finder scope so what this jupiter-sized planet that orbits orbits a white dwarf um what what that that is a a type or a that's an exoplanet that goes between the star and the telescope it's just a chance alignment but if you look at enough stars that have planets some of them will go across the face of the star and this is very valuable for astronomers because when the planet goes between the star and the telescope then the light from the star goes through the atmosphere of the planet and then gets to guests to web or hubble or whichever telescope's looking at it we can analyze that light that has gone through the atmosphere and determine the constituents of the atmosphere this is one of my colleagues call it sniffing alien atmospheres to see what atmospheres on other planets are made up of and so we can look for things like um you know we've already already with hubble we found hydrogen and some some nitrogen and and but with web we'll be able to start looking for molecules like methane and carbon dioxide and water vapor and look for the types of atmospheres that um might be indicative of planets holding at that would be conducive to having life on the planet uh ozone uh and so forth um that's a that's a very exciting thing that webb can uh will be able to do and we've got a long list of targets some of them were found like this this discovery that you mentioned some of them that were found by tess others that are found by ground-based telescopes and other projects but but the transiting exoplanets are sort of the most valuable uh for follow-up because we can look at their atmospheres but we also have the capability of uh looking with finer detail and separating the planet from the the very bright star that it's in orbit around and getting direct uh reflected light off of the planet or emitted light if it has any um so we can do both those techniques both what's called coronography where we block out the light of the star and see the planet next to it and then also transiting exoplanets and as i mentioned um one of our instruments the nearest near infrared near infrared imager and slitless spectrograph has a special mode that is particularly designed to look at transiting exoplanets around stars that are fairly bright like even perhaps some stars that you can see without a telescope those are bright they're nearby often and we can get the because they're so bright we can get the best data and learn the most about those kinds of planets so yeah we're looking for small rocky planets like the earth earth like planets we're looking for looking for the atmospheres of those planets and uh hopefully we'll be able to see whether or not some of those planets might have liquid water on their surface um like i said uh beachfront property is um most valuable real estate in the universe yeah that's absolutely fascinating and we actually have a friend here on our server ryan mcdonald who is working on the project and he has done the paper on the white dwarf opportunity but i would like to ask you the journey with james webb has been long and complicated what has been the highlight so far for you uh so highlights of the project uh the i would say that that one of the things that i'm most excited about what web can do is studying distant galaxies this is actually the research that i did with hubble um uh both before i started working on web and also my own scientific research uh uh continues uh working with hubble to study the statistics of galaxies and the uh the change in the average properties of galaxies over time this is evolution of galaxies um this was a very first idea that um that astronomers thinking about what the successor to hubble should be came up with they wanted to understand how galaxies change and in particular how can we see uh further back in time to when the first galaxies formed after the big bang um so that's that's the type of science that i'm most excited about and uh you might be wondering how we can look backwards in time and that's because as you look at things that are further away it takes time for the light to travel from a distant star or distant galaxy to the to the earth to our telescope uh if it's the nearest star four light years away it takes four years to travel for the light to travel from there to here so we see that star as it was four years ago but with galaxies um the nearest galaxy is a million light years away and distant galaxies can be billions of light years away and the universe is 13.8 billion years old so 13.8 billion years since the big bang and hubble can take us to galaxies that are within the first billion years after the big bang that's how far we can see with hubble but when we see when we look at those galaxies some of them appear to us to to have evolved stellar populations so the stars in the galaxies are indicative that they're already several hundred million years old so to see the first stars sorry the first galaxies that formed in the universe we need to go further than hubble and that's uh that's the the initial motivation for a telescope that's bigger than hubble and that goes further into the infrared so looking backwards um to when the first galaxies form it it's kind of a paradigm of physics that if you can specify the initial conditions if you know what something's like when it first started it's much easier to understand changes over time so how those how the the gas from the um that started in the big bang turned into galaxies evolved over time to be galaxies like our own milky way with stars and uh planets in them um so that's that's the that's the science i've been uh most motivated by and i'll tell you there's a really cool piece of technology in our near-infrared spectrograph that will make that um that science uh easier and that's a micro shutter array um so this is a mems device men stands for micro electro electro mechanical systems mems it's basically a moving part on a chip on a computer chip so we have a an array of tiny windows each window is 100 by 200 micrometers so a tenth and two tenths of a millimeter and each of these windows is individually openable or closable through by sending commands to the telescope so what we'll do is we'll point the spectrograph at a a field like the hubble ultra deep field that's filled with galaxies and will open up the little windows where there's a galaxy and will close the windows around it to block out any contamination background light or or other galaxies and be able to measure the properties of a hundred or more galaxies in each picture and so to build up the statistics of how galaxies change over time we will be able to instead of doing them one at a time or maybe if you have a long long opening long slit opening you can get two at once if you line it up right we'll be able to do a hundred galaxies at once and this will give us the statistics to understand things like the formation of the heavy elements over time how did those how did the elements build up in stars and be redistributed through supernova and then form into later generation stars that build up over time from the first galaxies to the present day that's actually the capability that i personally am most excited about in this telescope other astronomers have their favorite uh favorite um part of the instruments or the favorite science that they're going to do as well fantastic fantastic as well uh black falls are also the universe's greatest mystery and what secrets could theoretically be unlocked using the james webb telescope sure so black holes um are by their nature um they're black in and of itself they don't emit any light however uh anything falling into a black hole will get um get heated up as it falls down basically the gravitational energy as things fall into a black hole heats it up and and makes the makes it glow it black holes will also tear apart anything that's falling into it so something that starts out as a star that gets too close to a black hole and starts to fall in it'll get ripped into pieces and uh turned into a stream or even a disk of material around the black hole that disc will heat up and start to fall in as material falls in over time the black hole then gets bigger it accumulates mass and so webb will be very good at studying this how black holes grow over time particularly black holes that are in the center of galaxies we have shown with hubble astronomers have shown with hubble and other telescopes that pretty much every large galaxy has a black hole in its center whether or not it's it's a bright one if it is if it is very bright it's called a quasar if it's moderately bright it's called an active galactic nuclei or agn and then some black holes in galaxies you can only tell they're there because they're um of the the effect on the on the stars in the galaxy their motions but um they're not it's not emitting emitting light but there's a black hole at the center of most galaxies including our own milky way and determining what powers these black holes how they um how they accrete matter and um uh how they grow and what causes the emission um often often these discs around black holes are very dusty they've got lots of the heavier elements that build up into little pieces of dust and that dust will block visible light but the infrared light that webb will see can get through dust clouds um kind of like radio waves can go through even the walls of your house and get into your you know your wi-fi receiver on your computer um infrared light can get through dust clouds and so we'll be able to see into the inner parts of these discs around black holes see how they're how they're powered and also a really interesting thing is that since we since every galaxy has a big black hole at its center um there's a relationship between the size of the galaxy and the size of the black hole and that means that galaxies and black holes grow together they change over time together and figuring out why that happens and how it happens will be one of the goals of webb for studying black holes i mean it sounds amazing yeah that really does dr jonathan i was wondering whether you could talk to us today it's all about luvoir what could you share with us today about luffoir sure so um just as in 1995 astronomers got together and and started thinking about what should come after hubble um astronomers now are starting to think about what comes after webb and in fact every 10 years there's a process run by the united states national academy of sciences which will look at all of the the ideas that people have it's a really big process and results in a book length report and it's done every 10 years so it's called a decadal survey of astronomy and astrophysics and that is provides the recommendation to nasa to the national science foundation and this year also to the department of energy within the united states about what each of the agencies should do in the area of astronomy and astrophysics so the web telescope it wasn't called that then but in the 2000 decadal survey was the number one priority so nasa said all right we've had this as an idea let's just start building it now and in 2010 the um the top recommendation was a project called that at that time was called wfirst or the wide field infrared space telescope now it's called the nancy grace roman space telescope named after uh the astronomer who worked for nasa that is considered to be the mother of the hubble space telescope nancy roman and the the uh the roman telescope will be uh the same size as hubble but a much bigger field of view it will be able to map the sky large areas when you look at large areas you can find rare things and if we can get roman launched before the end of webb's mission we'll be able to have the two of them working together so you asked about luvoir so luvoir is one of the possibilities that is currently being studied for what is the 2020 decadal survey they're they're about to bring it out in a couple of months and um astronomers and and nasa are eagerly waiting to see whether um whether luvar gets the thumbs up for um being the successor to web the successor to the roman roman space telescope um and the next big thing so luvoir would be even bigger than webb and uh going back to visible light ultraviolet light it's called the large uv optical infrared telescope that's what luvoir stands for there are competing concepts there's uh there's an idea a mission called havex or that would be focused on studying exoplanets there's a uh a mission called the origin space telescope which would be taking beyond web in in further into the infrared longer wavelengths and then there's an x-ray telescope called links those are kind of the four concepts that the decadal survey is looking at and we'll be making a a ranked priority list which which one do we does that should nasa be starting first um so lupoire is a better even than web at studying exoplanets and looking for either the conditions of life or possibly even what astronomers would call biomarkers which would be um consid um things in the atmosphere of an exo exoplanet that probably can only be there because of uh because there's life on that planet so that's something that that's probably beyond the capabilities of web although astronomers will certainly be looking uh looking with webb to look for the conditions of life but webb will probably be able to tell us whether or not a planet has um liquid water on its surface is it the right temperature for water-based life but uh seeing things like um ozone and methane and disequilibrium the way they are in the in the earth uh the earth's atmosphere the ozone and the methane in the earth's atmosphere is maintained by life on earth perhaps directly if you can see the color of chlorophyll that's an indic indication that you've got plants and again if you if you looked at the earth from space and you you could see that there is green there are green forests there are plants um you can you can see the uh the colors of chlorophyll those kinds of things are beyond webb but that's what luboir is designed to do amazing amazing um we've talked about uh things coming online and offline and everything but we've seen the likes of mars insight and juno the juno mission getting mission extensions recently and would you fully expect james woods telescope to last double or triple it triple its planned operational use a bit like hubble's continually ongoing right so um with webb we have only one thing that gets used up over time and that is fuel so web is in uh in orbit around the second lagrange point that's not a stable point it doesn't just stay there um we have to use the the rockets the thrusters to maintain that orbit so we'll be firing the rockets about every three weeks during the course of its mission not using a lot of fuel but it does use up the fuel that we have on board to maintain that orbit if we didn't do that it would drift away from the l2 point and get too far away from the earth the other thing that we need to do with those rockets is uh manage the angular momentum of the observatory so when we point the telescope the the sun shield acts like a sail and the sun will push on it and impart angular momentum into the telescope um and then we point in a different direction and it builds up in a different way we store that angular momentum in reaction wheels and every so often we need to use the the thrusters to get rid of that angular momentum into space again about every three weeks we'll use the rockets and webb will carry 10 years of fuel so 10 years is is the nominal lifetime of of the mission because um when we run out of fuel then we no longer can uh can operate the observatory but um it's always good to carry some extra just in case and so we've topped up the tanks all the way to the top and so we do have extra fuel how much extra fuel we won't know until after the launch and that's because some of that fuel in the tanks is there just in case the launch doesn't go quite right so if we get a really good launch that puts us right onto the track to uh the l2 point you know exactly the way we want it then that extra fuel directly translates into extra lifetime and there's a lot of leverage on that um we we could be getting you know five years longer uh maybe even more than that so the prospect of um of having webb continue to work uh well into its second decade is a very real process possibility um the uh the nominal prime what's called the prime mission is actually only five years but that's really just a planning a planning thing we've got you know we've got the budget for five years in the plan but just like hubble we know that nasa is going to keep it going as long as it works it's hubble's lifetime is not going to be limited by money it's not going to be that oh we decided it's not worth it anymore we'll keep it going as long as as long as it's returning good science we'll keep hubble going um same is true for webb so with um there's been a lot of uh incredibly fast advancements with spacex especially but also other major players in the space industry we might have new glenn here soon and many other options that were not even on the radar when james webb was first being designed is do you think that are there any uh options that are currently being considered for serviceability for james webb exploring for example the possibility to use a starship or many of the other options that are coming down the road so um you ask about serviceability so hubble was designed to be serviced to some extent you could say that the space shuttle and hubble grew up together that um the launch of hubble was one of the most challenging launches on the space shuttle um that it did so the space shuttle was sized to hold hubble and hubble was sized to fit in the in the bay of the of the space shuttle but hubble was also designed to be very modular you know if you if you look at the pictures of these astronauts pulling the cameras out they kind of you know they've got handles on them and they just slide out um and they're they're it's like pulling a suitcase out off of a shelf um it's designed to be a a single uh a thing that's on rails that comes out um the the choice was made or the trade was made early on for webb that we would not make the uh mission the observatory modular like that because when you make it when you make the it modular you end up putting a lot of extra mass and volume into having that serviceability essentially if you don't design it to be serviceable you can make things much more inter inter connected fit much tighter um and uh you know you can put one instrument in the middle and then you can put another one on the outside um and that's the way web was designed uh basically to make it lower mass and more capability in the same amount of mass the same amount of volume web is also cryogenic it's it's very very cold once it's fully deployed and cooled we wouldn't want to have anything get too close to it because any kind of gases would condense on the telescope fog up the mirrors and so forth so we don't have plans for servicing webb it was not built it was not designed to be serviceable it doesn't have that modular design the way hubble does that said if it's not working and somebody wants to go out there and fix it um i would be all for that uh but um but we we're at at this point um and for the last 20 years we've been very focused on getting the telescope launched um uh with its current design and not adding complication or mass or volume in order to uh to make it serviceable um because at the moment we don't have the capability of going 1.5 million kilometers from the earth that is four times the distance of the moon so the furthest that we've sent astronauts it's four times that distance uh to get out to the l2 not impossible but um you know um there um there will be human uh space flight missions out that far and and further uh in the future um but we don't have that now and so it's not designed for that yeah absolutely at this point we take one q weaver question uh joey asked what can you say about how how wavelength spend around distant galaxies and how likely is it that we can get multiple views of the same distant galaxies at different times in the past yeah very good question um what you're referring to is called gravitational lensing and that is because under general relativity einstein's theory of gravity light itself responds to gravity you can kind of imagine if if you think of light as as photons particles they would have a mass and they would fall into um fall into a gravitational field it's like that it's actually a little bit um more than that with uh general relativity but that means that a big concentration of dark matter or even light matter with a strong gravitational field will bend the light that's going by there so when you have a cluster of galaxies and behind it you've got um more further further away you've got other galaxies the light from that galaxy will kind of go by the cluster and get bent around and fall into it as it goes um and if you've got it lined up right you can have light that comes out um light goes in all directions from the the lens to object the the distant galaxy it goes out this way and it comes around i don't know if you can see this with the camera but comes around the galaxy and reaches the telescope from that direction and then it can go around the other direction and reach the telescope um so light that went out in two different directions will then get focused back and and reach the telescope and if those paths are different then you're seeing light from different times because it took longer to get there that will happen most often with um with a a very high concentration of of dark matter like perhaps even a um lensing by uh by a black hole but by measuring if you can actually have something that varies over time and you see the light change in one image and then you see it change a little bit later that's a way of measuring properties of the universe itself the um the distances and and basically the shape of space-time so that's a very powerful uh observation and this astronomers are very excited to make that kind of observation so we have two advantages of gravitational lensing one is that just like a telescope or like a lens it can make things brighter um so we can see very distant galaxies um you know maybe tens of times 30 40 times brighter than it would be without the lens and that means we get more light it's like we have a much bigger telescope um and uh so that's also an advantage of gravitational lensing is that we it magnifies the um the light and we can we can get a lot more information about those distant galaxies than we would without the without the focusing effect speaking of light uh you were talking earlier uh dr gardner um we're something that i'm curious about is uh with the phenomenon red shifting we know that light over time shifts to the to the infrared spectrum uh because of this assumedly uh james webb would have a maximum range of detection before the uh the wavelength is no longer detectable by james webb um what do we know what the maximum range of the theoretical maximum range of james webb is based on the redshift effect so yeah that's a that's a good question um the limit is for hubble and webb goes far enough that we're not expecting to hit that limit so that is fundamentally um the reason why hubble has a limit to how far it can see so light is light from stars particularly young stars that are just forming uh comes out in the in the ultraviolet but once it gets past a fundamental transition of hydrogen the gas between the galaxy galaxies and gas between the stars will just absorb all the light so there's a there's a limit to how short of a wavelength um that you can see from a star or galaxy that gets stretched out by the expansion of the universe when you're looking at things that are far away and it's actually a good way of knowing if a galaxy is very far away is that you just don't see it in the bluer filters you do see it in the redder filters there's this big sharp break where the gas between the galaxies is just wiping out all of the light so hubble has a limit of how far it can see because based on how far into the infrared it can see and that limit is something like a bit less than a billion years after the big bang webb was designed from the beginning to go out further into the infrared by a factor of um more than 10 at between about 15. so 15 times um the redshift uh webb could still still see the the wavelengths um but what we expect is that there won't be anything there to see because what we're hoping to do with webb is to get to the point where the first galaxies in the field that it's pointed at where those first galaxies were formed and um we expect we expect to see forming galaxies baby galaxies at the at the very distant um very high redshift and then when we look at higher redshifts than that we don't see anything because there isn't anything there or there isn't any um concentration there's not a galaxy there there's just gas that's great thank you so web is not going to be limited in how far i can see by by the by the redshift in the way that hubble is nice we are quite the international a bunch of people here so we are quite interested in the collaboration between space agencies you all already mentioned different instruments from sr canadian space agency nasa but how will that be in future who would operate what instrument and could you tell us about it more sure yes web is a product of the world as i mentioned it's it's jointly between nasa um the european space agency and the canadian space agency all three agencies are contributing hardware to the mission in total there's 14 countries that uh worked on hardware the us canada and 12 european countries all of the partner states of of esa contributed at least money and and uh software and so forth um but um but it's it's it's a it's an open process for what science we do so nasa's the lead so we we will we run every year we will run a open competition to select the very best ideas for where the telescope should be pointing and um the time on the telescope is allocated by hours so there's 8 600 hours in a year and each year we will take up to that number of proposals up to um you know some proposals will be smaller ten hours there'll be some big proposals with a hundred two hundred hours um maybe even bigger um but each year there's an open competition and astronomers from around the world send in their proposals for what they would like to do and how much time they want on the telescope to do their project those proposals will are read by a team of um of scientists about um up upwards of 200 scientists are involved in this in this review all in different panels for different science areas uh they they pick the best science and um that's what we'll do and then a year later we'll have another call we're right in the middle of that for the first year um the proposals went in at the end of november there were um almost 1200 proposals something like 45 different countries contributed proposals proposals from around the the united states and europe of course canada but also um asia uh australia just all all around the world there were astronomers who would write their proposals and um nasa esa and csa we want to do the best science that this telescope can do this is a this is a product of the world and it's it's a contribution to the world um everybody should benefit so um so the the peer review has uh just met they just finished um making their their decisions um it's now in the final review stage and in probably about two to three weeks um the the first year of observations will be announced what projects we'll be doing and it's it's open to anyone around the world speaking of international collaborations here we heard that you have a little bit of an international connection yourself yeah so i after my phd um so my history is um i went to college at harvard got a bachelor's in astronomy and then went to graduate school at the university of hawaii um there is a bit of a space story in that while i was an undergraduate my the summers after my third year and fourth year of of university of college i was a summer intern at the goddard space flight center where i work now had a project working with uh with a camera for the spitzer space telescope and um i graduated i got my degree in 1986 which was a very um not a pleasant year for space that was the challenger accident um i wanted to work in space astronomy in some kind of space field but with the challenger accident that it was clear that that was going to delay uh the launch of hubble the launch of hubble was originally going to be late in 1986 instead it was launched four years later once they got the shuttle flying again so with that i decided to uh give up on space for a while anyway and i went to hawaii where they have the big ground-based telescopes i did my phd in 1992 from hawaii and i got a nato fellowship to go to the university of durham in the north of england which has a very strong department in cosmology in the study of of galaxy evolution i was there for um on on the nato fellowship and then again as uh after that i was picked up as as a university of durham postdoctoral researcher i was there for four years and then by 1996 hubble had been launched in 1990 they had the first servicing mission to repair the optics in 1993 and they were about to put on the telescope uh a spectrograph called the space telescope imaging spectrograph and an infrared camera the near-infrared camera just the shorter wavelengths called moss and i was hired by the the spectrograph team to come to goddard um to work with uh with the data from hubble um but i i lived for four years in england um i had a great time there durham is a beautiful city while i was there i got married so my wife is uh is local to that area she grew up in the city of darlington which is nearby durham and she was working in durham at the time um she followed me to the united states uh and um here we are we have three kids we've been married for 25 years fantastic um just jump into hubble as you mentioned it there it's obviously near it's the end of its operational life what would you like to see happen with it um salvage some parts for public display somehow i know we've got some future salvage missions to try and bring uh just base junk down back down to earth i'll try and just get rid of it all together i would like to see maybe at least recover a portion of it or something like that maybe to put it within a museum rather than because i believe the theory at the moment is just to de-orbit it in some some form yeah so first of all as i mentioned earlier we'll keep it going as long as it goes as long as it keeps working as long as it keeps able to do science we will keep hubble going because um it's actually working very very well right now well past its design lifetime but unlike web it doesn't have any anything that gets used up in low earth orbit you don't need fuel to maintain the orbit it does have it will eventually come down the the orbit that's in uh there is a l enough residual atmosphere to just slow it down a little bit over time and that i think that the current prediction is sometime in the 2030s it would deorbit it would come down and um we can't let it just fall because you can't have a big thing like that fall on the ground where there might be people um so the current plan is to go up with a uh with a steerable rocket to steer it into the pacific so it doesn't land on on people um when it was first built the idea was that it would be brought down by the space shuttle at the end of its lifetime um to put in a museum um the decision was made after uh two space shuttle accidents that it wasn't worth um that at risk um just for a museum piece um iconic as it is um so uh we don't have a plan to uh to bring it down it it's i know you're you're uh your viewers understand this pretty well but it's it's as hard to land something as it is to to launch something okay it's hard to bring something down safely and have it have it come down safely as it is to launch and uh um and to some extent as expensive um so uh of course um people are thinking about what happens um uh you know the astronomers um i think the world hopes that hubble keeps going for a number of years as i mentioned earlier we would love to see hubble and webb working together because they are complementary web is a successor it's not a replacement so we want to keep hubble going as long as it can and what happens at the end well we'll need to keep it safe but uh of course people are thinking about maybe we could send another mission up there to uh to get it going again or to boost it to an even higher orbit um who knows yeah it's been absolutely fantastic to have you on there dr jonathan absolutely fantastic we could possibly quite possibly just talk all night uh with yourself i'm sure everyone else feels the same here um obviously after the show he'll got some questions from the viewers but uh i'm sure that's gonna wrap up the show here now because uh always will be going on for hours on end i think uh thank you for joining us on this week's episode everyone uh i've been ryan from the space update i've been mikko the host of deep dive fridays i've been rich i'll be close to becoming multiplanetary and i've been kage also co-host of becoming multi-planetary thank you very much i've enjoyed talking to you thank you very much jonathan um and big big thank you to everyone listening to all our patreon supporters uh anthony mann warhawk angry astronaut howard walker samuel skuro what about it to the future kyo pakulari rick susie and marco if you would like to uh support what we do here at total space network and gain access to exclusive content early access and to check to get your show hosts after the show like today and head over to patreon.com forward slash total space and where else can you find us guys you can find us on uh totalspace.net we have a uh well it's not so new anymore but uh newish uh website um you can also find us on uh various social media platforms including on twitter uh total spacenet uh we have a not so active instagram currently but uh we do have one um but you can find all of our socials on totalspace.net and just before we wrap up actually uh dr gardner do you have anywhere where we could find you on the internet and follow your work well so you can learn about the web telescope by at web.nasa.gov so watch us as we ship it down to south america and count we count backwards in french because it's an ariane 5 launch and hit the big red button and off to l2 you

Channel: Total Space

Views: 1,314

Keywords: Dr. Jonathan Gardner, European Space Agency, Interview, JWST, James Webb, James Webb Space Telescope, Jwst deployment, NASA, Nancy Grace Roman Space Telescope, Podcast, Space News, The Space Update, Total Space, ariane 5 james webb, ariane space launch vehicle, biomarker detection, exoplanet astronomy, exoplanet atmosphere, hubble space telescope, james webb launch, luvoir, planetary migration, solar gravitational lens, solar gravitational lensing

Id: b15sG7k1GMU

Length: 72min 9sec (4329 seconds)

Published: Wed Mar 24 2021