Transcript: Space4U podcast, Jonathan Gardner

Written by: Space Foundation Editorial Team

Hello, this is Andrew de Naray with the Space Foundation and you’re listening to the Space4U podcast. Space4U is designed to tell the stories of the people who make today’s space exploration possible. Our guest today is Dr. Jonathan Gardner. Jonathan is the deputy senior project scientist for the James Webb space telescope, and also serves as the chief of the laboratory for observational cosmology in the astrophysics science division at NASA Goddard.


He received his bachelor’s degree in astronomy and astrophysics from Harvard university. And while he was an undergrad, he spent two summers as an intern at NASA, got Goddard working on an early design of the infrared array camera for another well-known space telescope Spitzer. He attended graduate school at the university of Y earning a master’s degree and then a PhD in astronomy studying the evolution of galaxies using infrared observations, following graduate school, he won an NSF NATO fellowship to pursue his research at the university of Durham in England later returned to Goddard to work with the space telescope imaging.


Spectrograph a camera that was installed on the Hubble space telescope in 1997. He began working on Webb as a member of the ad hoc science working group in the late 1990s and joined the project as the deputy senior project scientist in 2002. In this role, he helps the senior project scientist, Dr. John Mather oversee the scientific performance of the telescope.


Dr. Gardner, thank you so much for joining us today. Thanks for having me. It’s my pleasure. We’re here to talk about James Webb space telescope. So I’m going to give a brief primer on that. Also known as Webb or JWST for short, it will be the largest, most powerful and complex space telescope ever built and launched into space.


100 times more powerful than the Hubble space telescope. And it promises to fundamentally alter our understanding of the universe. It’s longer. Infrared wavelength. Coverage and greatly improved sensitivity will enable Webb to look back at the beginning of time, peering back over 13.5 billion years to see the first galaxies born after the big bang, how you may ask we’ll get into that shortly.


Additionally, it will hunt for the formation of the very first galaxies while also looking inside dust clouds, where new stars and planetary systems are currently forming today. On top of all that we’ll also analyze the atmospheric compositions of more recently discovered exoplanets and even assess whether they may be capable of supporting life.


The project started in 1996. Yes, that’s 25 years ago and is currently scheduled for launch on October 30. First of this year, the telescope is an international collaboration between NASA European space agency and the Canadian space agency with NASA Goddard managing the development effort. Webb has over 1200 scientists, engineers, and technicians from 14 countries and 29 us States currently building it.


And it will also provide service to astronomers globally. So far with more than 4,000 astronomers from 44 countries in 45 States having submitted proposals for the first round of observations. And it’s almost a $10 billion price tag. It’s one of the most expensive space missions in history. Was that a pretty adequate summary there?


Jonathan? Yeah, very good. Um, I’m wondering what, what we have to add, but we’ll find some things to talk about. Let’s dive into questions. We got some of those. Uh, as I just mentioned, they’re in the preamble, a popular phrase used to describe Webb is that it will see 13.5 billion years into the past, and even see the first light created in the universe.


Could you give us an explanation that we can wrap our heads around of how Webb will let us see what the universe was like shortly after the big bang? Sure. Telescopes almost always are time machines because of the time it takes for light to travel. When. Light is emitted by a star. That’s say four light years away.


Our nearest star that life has taken four years to get from the star to our telescope. If we look at stars that are a thousand light years away, we’re seeing the light as it was submitted a thousand years in the past. And when we go to galaxies, And we’re talking about millions or even billions of years into the past.


So this isn’t a new, a new technique. It’s something that, uh, telescopes have been doing since the invention of telescopes. But what Webb can do is to see even further away and therefore we’re looking even further into the past. So we know that the universe is 13.8 billion years old. Since the big bang and Hubble has managed to take us into the first billion years after the big bang.


But one of the things that is interesting when we look at the very faintest galaxies, the very deepest pictures that Hubble has taken, some of those galaxies. Which are emitting their life at a billion years, or even less than a billion years after the big bang are already several hundred million years old when they were emitting the light.


So in order to see even further back into the past and hopefully define the first stars and galaxies that formed after the big bang. Uh, we need a telescope that can see further and to do that, we need a telescope that’s bigger, collects more light from very, very faint galaxies. And also, uh, we needed a telescope that can see further into the infrared.


Now, the reason why we need to go into the infrared to see further than Hubble is because as the light is traveling for billions of years across the universe, the universe is expanding. Has the expansion of the universe takes those wavelengths of light and stretches them out. So light that started out as blue light gets stretched into longer wavelengths and.


It appears to us as red light, or even if we’re going this far back, like that was admitted in the ultraviolet. So blue that we can’t see it is stretched all the way into the red. So red that we humans can’t see wavelengths of light, um, in the infrared. So this is one of the reasons why the James Webb space telescope is optimized for the infrared.


And it’s the reason why we needed a telescope. That’s. Bigger than Hubble in order to see these first galaxies and the, uh, JWST his predecessor Hubble space telescope. It’s provided us with these, you know, more than a million amazing cosmic images. And it’s 30 plus years of service now. And it shows all these awesome formations of.


Like space, dust clouds. Uh, but what some people may not know is that those dust clouds actually hindered the telescope from seeing the objects beyond them. Can you explain a bit about how, what we’ll see through these clouds and how that’ll be beneficial? Sure. The dust clouds are actually. Uh, clouds of gas and dust in our own galaxy, which is where stars and their planetary systems form, uh, the, the stars format of the gas, primarily the, the dust condenses into planets.


And so this is kind of where the action happens in forming stars within our own galaxy. So very, very interesting regions. And one example is one of the. The nebulae and the Ryan constellation is a place where new stars are being formed. But because these stars form in these dusty clouds, the dust stops the light from getting out.


If the wavelengths of the light are shorter. Then the, um, the size of the dust grains. So dust absorbs blue light, but infrared light, which has longer wavelengths can kind of go past some of the dust particles on the way and can get out. So when we look at a star forming region with Hubble, what we see is very beautiful pictures.


Of dust clouds and the densest part of those clouds are where the action is happening and that light doesn’t get out in the visible light that Hubble can see how we can see a little bit into the infrared, but Webb we’ll see much, much further into the infrared where the light is getting out of those dust clouds.


And we can seek into where the action is happening in the stars and the planets are forming. Very cool. And I’ve heard that Webb will create a 3d model of the universe together with Hubble. This sounds really cool. How will they work together to achieve this? So generally measuring distances to things is actually, uh, often, uh, a challenge with astronomy.


We have to use techniques because when we take a picture, it’s essentially a two-dimensional picture. We see where things are on the sky, but two stars that are very different distances away from us. They’ll look like two stars and we have to use other clues to measure distances. Now, one of the things, when we’re talking about galaxies, especially distant galaxies is again that the universe is expanding over time.


And the further away that galaxies are the faster they’re moving away from us. This is called Hubble’s law. It was discovered by Hubble the astronomer, Hubble the telescope that was named after the astronomer. Um, and is one of the most fundamental discoveries in astronomy as of the last century, uh, that the universe is expanding.


And of course, when we wind the clock back and think about if it’s expanding, that shows that it had a start with the big bang, but as we go further and further out, the galaxies are moving faster away from us. It kind of looks like we’re in the center of this expansion, but that’s a bit of an illusion because that’s true for anybody anywhere on any of the stars or galaxies.


If they look in every direction, everything is moving away from them. It’s because everything is moving away from everything else. Anyway, as we look at these galaxies, we can measure their properties of the light and see the Doppler effect, which is the, a shift in the wavelengths of the light. Uh, as I said before, a light that’s submitted as blue light will appear to us as red light.


And we can measure that and measure the velocity that the galaxies is and moving away from us and therefore apply Hubble’s law to know how far away they are together with hovel Webb. We’ll build this 3D picture of what’s out there. It’s essentially a matter of getting more information, um, humble can measure the philosophies as well, but together the two are very powerful combination.


Okay. Cool. And, uh, you were saying we needed to achieve all these things, a larger telescope, but which way is, how does Webb compare in size and mass to Hubble? So the important thing for the astronomers, it’s the size of the mirror. The collecting area of the primary mirror, uh, Webb is 6.5 meters in diameter.


Um, Hubble is 2.4 meters in diameter. And of course then when you compare the collecting area, you square that, uh, ratio, but in terms of the whole spacecraft or the observatory, Hubble is actually more massive than Webb by about a factor of two. Webb is six and a half metric, tons, and Hubble is about 11 metric tons in mass.


In terms of size, uh, they’re very different shapes. So I don’t know if you list, you would like to Google a picture of Hubble and a picture of when they can compare, um, the very different layout of how the two observatories look, but the size of Webbs, sunshine shield, which is a, a large kind of umbrella that protects the Webb from the sun.


Like that’s about twice as big. As the Hubble tube, 22 meters compared to 10 meters. So Webb it has a bigger mirror. So that’s the collecting area. That’s the important thing to the astronomers, much bigger mirror than Hubble. It’s lower mass, but about twice the size. So it’s about six times the size of Hubble’s primary mirror.


And my understanding is that it’s coded in real gold. What’s the benefit of that. So gold is very highly reflective of infrared light. So that’s, it’s as simple as that gold is, is the best material we have to reflect. Infrared light Hubble in comparison is the mirror is coated in aluminum, which is reflective of ultraviolet light and physical light.


Now. The price we pay for having a gold coated mirror for Webb is that gold does not reflect blue light. It absorbs that. So where we’ll be able to see some visible light starting with gold colored light and moving redder, but we’ll not be able to do anything in the ultra violet or blue light. The way Hubble can, but then when we get into the infrared cold is very reflective and it’s the best material for that.


What this means is that Webb is not actually a replacement for Hubble. It’s a successor. So what astronomers really, really want is to use the two together. We’re already planning to use Webb to follow up a lot of the discoveries that Hubble has done, but what we would really like is to then go back and get more information using Hubble for things that we had just looked at and maybe some new discoveries that were makes.


So they do have different capabilities. But Webb is the successor, uh, rather than a replacement. And that is always a good reminder, you know, how much telescopes work together, you know? Um, and for the listeners, it’s, it’s only about 1.5 ounce of gold, I believe, uh, like a golf ball size of Mount. So that’s not a huge part of the budget.


Yeah. So couple orbits earth in lower earth orbit or Leo, but the JWST will actually orbit the sun outside of the earth and following Earth’s path. What’s the reason for that. It’s actually in orbit around a position called the second Lagrange point. This is a very special orbit. The second Lagrange point goes around the sun with the earth.


So the sun, the earth and the L2 point as we call it are always in a straight line. So the earth goes around the sun once per year. And the L2 point goes around the earth once per year. Exactly lining up with the sun or hell to lie. And we chose this orbit because of the way that Webb is designed.


So, as I said before, Webb is an infrared telescope. And anything that has a temperature will emit light in the infrared. So in order to be able to see the distance stars and galaxies with infrared light, we need to have a telescope it’s very cold because otherwise the heat from the telescope will get into the cameras and wash out the signal of what we’re trying to look at.


So Hubble is room temperature, essentially, as it goes around the earth. And it goes in and out of the sunlight every 90 minutes as it goes around in low earth orbit. And when it’s in the sunlight, it warms up. And when it’s on the nighttime side of the earth, uh, it cools off, but not very much. And actually to maintain the temperature stability.


There are heaters on Hubble that keep it at a pretty constant temperature. And that that temperature actually limits Hubble’s ability to see very far into the infrared wavelength region. So with Webb, we needed a telescope that’s very cold and so Webb will be capped at about 225 degrees below zero Celsius.


And that’s 50 degrees about the absolute zero temperature. Uh, and in order to achieve that, we have to shield the Webb from sunlight. All the time. And so we have a large kind of umbrella, 22 meters. It’s it’s the size of a singles tennis court. And there are five layers, each layer as you go from the sun side to the telescope side, each layer gets colder and colder so that the mirror stays in the dark.


And can cool down to these very, very cold temperatures, but it’s cold enough that even getting light reflected from them, the sun off of the earth onto the telescope would heat it up. So we put the Webb at this second level branch point where the earth and the sun are always lined up so that the sun shield can protect the telescope from both sunlight.


And from the earth light, and we have actually have to keep the moon behind the sun shield as well. So that’s the main reason for putting it in this special orbit. It’s a, it’s a million miles away from the earth. So about four times the distance of the moon. Okay. And because of the interaction between them, the sun’s gravity in new York’s gravity things that the L2 point will pretty much stay lined up.


As we go through the orbit. Um, the once a year who are a bit around the sun, normally something by Kepler’s law would something that’s. Is there a way from the sun than the earth is, would trail behind drift away, but the Earth’s gravity just kind of nudges it a little bit and keeps it all lined up.


That’s what makes it special about that? The second grunge point. Um, and they’re named after the French mathematician and astronomer Luc Lagrange, who was working about two centuries ago. He worked at these orbits. Wow. That’s interesting. So let’s talk a bit about the suite of tools that Webb has to achieve its objectives.


First there’s the near cam, uh, which is short for near infrared camera, which we’ll be able to see the oldest stars in the universe, as we mentioned earlier, and this may coincide with mapping out the universe, but, uh, it will also help create a map of dark matter, a form of matter thought to make up about 85% of the matter in the universe.


But it’s still largely a mystery to us. What might this mapping reveal about dark matter or change? What we understand about it? Great. So the way that the NIRCAM will create maps. So dark matter is through their gravitational effect, the gravitational effect of the dark matter. The thing about dark matter is that it’s dark.


It doesn’t emit any light. Or indeed any electromagnetic radiation at all. So it only interacts with other matter through gravity, which makes it very, very hard to see, but we can see the effects of the dark matter again, through the effects of gravity. One of the techniques we can use is gravitational lensing.


So this is where there is dark matter, along the path. Between our telescope and something even further away like a galaxy and that dark matter will either magnify or bend the light to the effects of gravity on the light itself, passing through this intermediate clump of dark matter as it were. And by making a map of that.


We can determine some of the essentially clumping properties of the dark matter. How big of concentrations are there? How many different concentrations we know that dark matter is associated with galaxies and with clusters of galaxies. So when there’s a clump of dark matter gas and dust falls into that and starts forming stars and, and eventually you get a galaxy, but by mapping the dark matter, for example, in a cluster of galaxies or in a galaxy itself through this gravitational lensing, um, we can determine some of its properties, how it interacts and match that.


With theoretical predictions of the distribution of the dark matter in the universe. And then, uh, there’s the MIRI or the mid-infrared instrument, which will allow us to see the new stars being born. Was that kind of what we were talking about earlier, as far as the space dust and everything, is that the instrument that’s going to be achieving that?


Sure. You’ve mentioned in the names of the instruments. We have the near infrared camera, which is the shorter infrared wavelengths. Near to visible light. And then we have the mid-infrared instrument, which is the longer wavelengths. There’s also far infrared, but wet. Doesn’t go out that far. We have other previous missions look at even longer way lengths.


But so the mid-infrared instrument, um, works with the longest wavelengths of light, the longest the, the reddest or the most infrared. It should say a light that Webb can see. And that’s where we can look into these dust clouds. The best, essentially, the longer wavelengths we get to, the more light can get through the dust.


And, uh, reach our telescope so we can see down into where the stars are actually forming. And again, see the discs of dust around those forming stars that will eventually lead to planets. Cool. And there’s, uh, there’s been a lot of debate about the potential existence of a hypothetical ninth planet in our solar system beyond Neptune called planet nine or planet X, but it’s never actually been observed.


Will Webb be able to officially confirm or deny its existence. So we’ve talked a lot about what Webb can do, which is to look very, very hard or look very deep in a small part of the sky. There are things of course, that Webb cannot do. And one of those things is to map a very large area of the sky and look for something that would be very rare.


So if we’ve got a ninth planet out there or even, you know, maybe a handful of additional planets, Very very far away. Webb’s actually not the best way of finding them in the first place. However, because we, it just doesn’t and large parts of the sky. We point wet where we know there’s something interesting.


And then it collects lots and lots of light that we can then analyze, um, to understand the thing we’re looking at. However, if some other, your telescope that is scanning large parts of the sky, find something that looks intriguing. Then that’s a good target to point where that, and find out a lot more about it.


So I think if we’re talking about discovering planet nine, it’s not going to be that people will be looking at Webb images and say, Oh, what’s that. Maybe that’s a new planet. It will be that somebody will be looking at data from a, another future NASA mission called the Nancy Grace Roman space telescope, which will map large parts of the sky.


Or there’s a project on the ground called the Vera Rubin telescope. That’s being built again to map large parts of the sky every night. And look for things that change. One of those two projects might well find something that. Looks intriguing. And then we’ll point where I’ve added and help to understand what it really is cool.


And, uh, Kepler discovered most of the exoplanets that we know. And so that kind of goes in with what you’re saying, as far as pointing it at particular things to observe them. Um, so they, the nearest camera or a near infrared imager and slit the spectrograph will that then locate exoplanets and then like the near spec.


Near infrared spectrograph Oh, then observe those. So it’s actually, um, both of them are ways of, again, following up or learning more about exoplanets that have been found by other missions. So Capla was a mission that found a lot of exoplanets in a patch of the sky, finding planets that moved between the star and the telescope.


So it’s just called transiting planets, um, sort of like an eclipse. Um, when the moon moves in front of the sun, that blocks the sunlight, but from the earth, you can also see mercury or Venus move it cross the face of the sun, not very often, but, but it does happen. And then when exoplanets are just perfectly lined up between their host star and one of our telescopes, we can also see that dip in the light of the star as the planet goes in front of it.


And when that happens, the light from the star actually goes through the atmosphere of the planet. And we can measure that and study the atmosphere using the nearest camera, especially there’s a particular mode in that camera. That’s very good for studying transiting, exoplanets, but that to measure the constituents of their atmosphere and look for things like, is there water vapor?


Clouds, um, methane carbon dioxide, which are, um, signs could be signs of life or could be signs that the planet might have the conditions that could have life, the actual detection or proof of life on other planets is a really, really challenging thing. And I think with Webb, we would have to get really, really lucky in order to, um, to actually see proof of life on other planets.


That might be something that would need to wait for a future, even bigger telescope. So the nearest, uh, has some, some specialized modes designed, particularly for exoplanets. The deer spec is our kind of workhorse spectrograph that can also not only study exoplanets. But another thing that is exciting about the near spec is that it has the capability of.


Observing multiple galaxies in a galaxy field at once to measure the properties of these galaxies. It has something called a micro shutter array. It’s a little. Um, moving parts on a computer chip where it’s got a quarter of a million little windows that can individually open up where there’s a galaxy to look at and close to block out the background light.


And, uh, with this, we can observe a hundred galaxies at funds and build up a statistical picture of the change of galaxies over time constituents. So, uh, we’ve been talking all about the distant galaxies, that level of observe, but what objects in our own solar system will we be looking at? So within our own solar system, because of where Webb is, it can see anything outside of the orbit of the earth.


So we can observe the, the outer planets, uh, look at, we can look at Mars. We can look at Jupiter, Saturn, Uranus, Neptune, as well as all of the. Sort of the, the leftovers of the formation of our solar system, which is called the Kuyper belt of which Pluto is one example of a Kuyper belt object. And we found, um, a bunch more, uh, things out there.


Those are, as I said, the leftovers of the formation of our solar system. So they can give us a look at what the protoplanetary. Dust cloud was like that our solar system formed in addition to that, because we can look the planets and their moons. We can learn a lot about the outer solar system. We’re able to observe Mars.


It’s kind of bright for a giant space telescopes. So we have to use some special modes to spread out the light. So I’m not sure we’re going to get. Nice pictures of Mars, but we’ll learn a lot about what’s going on with Mars, as it goes through its seasons in a way that’s very complimentary to the perseverance Rover that just.


Landed as we’re recording, this just landed on Mars this week. So the rovers will study what’s going on in great detail where they are. Whereas a telescope like Webb can look at what’s happening overall in the whole planet. And that’s true of all of the outer planets and their moons and objects in the belt.


Cool. And constant asteroids to ration. Say. So the telescope itself has actually been complete for four years or so. It’s been all testing that’s been going on since, uh, how do you test a unit like Webb to see how it will fare against harsh atmosphere conditions prior to launch? Like, how are those conditions synthesized for testing?


Sure. So we have to put it into a vacuum, which means that we need a vacuum chamber, that we can pump all the air out of. And we also have to test it at its operating temperature, which means we need to make the inside of that vacuum chamber. Very, very cold. And for the big test of Webb, the Webb telescope and its instruments, we used a vacuum chamber at the Johnson space center in Houston, Texas.


Uh, that was actually built for the Apollo program. And it’s 12 meters in diameter and 35 meters high it’s a giant vacuum chamber. And originally in the 1960s, the Apollo astronauts went inside this vacuum chamber and they practiced walking on the moon in their space suits. In a vacuum. So the Webb project kind of took over this chamber.


Um, a number of years ago, took out the, some of the Apollo stuff. They had a simulated lunar surface on the inside of the chamber. We took that out. We put in a, it’s called a shroud. It’s like a panels that have circulating liquid helium in order to bring it down to the operating temperature of Webb. Uh, we put the telescope in this chamber, took about a month to pump out all the air to let it cool down to its operating temperature.


We then spent a month checking out all of the instruments, um, shining little pinpoints of light. Through the telescope into the instruments, making sure everything works and testing all of the different components of the telescope and the instrument. And then another month to let it warm up and put the air back in.


And then, then the testing that we’ve done since then has mostly been to do with, will the telescope survive the launch? Because we’re going to take this very expensive, very high tech piece of equipment and put it on top of a rocket. And blasted off into space and that’s a pretty tough thing to survive.


Um, so we’re, we’re testing that as well. We have a vibration table, so we put the observatory on the, on the vibration table and we shake it. We shake it in all the directions and it various different frequencies. And then we also will put we’ve, we have put it into an acoustic chamber and blast it with.


Sound that, um, again, simulates what it means to be right near a blasting rocket as like being, you know, right next to a jet airplane engine. Um, very, very loud. So we, we have done that. We are now in the final stages of testing everything to make sure that it all still works after we’ve shook it. And after we blasted it with sound and the next step is to fold it all up and ship it down to the actual launch site.


The launch of Webb is part of the European contribution to the mission. So it’s going to be launched on an Ariane 5 rocket. And the launch site is in South America. It’s in cool French Guyana. That’s where the, um, the European rockets are launched from. So I should have said that, uh, earlier the Webb project is led by NASA, but there’s a significant contribution from the European space agency and also from the Canadian space agency.


So the Canadians contributed the nearest camera. The Europeans contributed the NIRSPEC camera, some of the hardware from the MIRI. And the rocket, the launch vehicle. So it’s a partnership, it’s a product of the world. True. We’re doing effort. Yeah. And as you mentioned there in its functioning state, the telescope is actually too large to fit inside any launch vehicles.


So it’s kind of an engineering feat in itself, really that it’s been designed to fold up for transport. Um, and then be unfolded when it reaches its destination. I’ve heard that this is roughly. Three week unfolding process. Can you explain a bit about why it’s such a long and intricate process? Sure. So, yes, as you said, uh, the six and a half meter diameter mirror is going to be launched in a five meter diameter rocket.


So we had the folded up. This actually also helps it to be lower mass. So the, the Hubble mirror is a solid piece of glass that was formed in its, in its shape and then launched. And, uh, is that. Same shape that was launched in. Whereas Webb has made that the primary mirror is made up of 18 individual hexagonal mirror segments arranged into a kind of a larger hexagon.


And, uh, each of those segments are 1.3 meters wide and they’re, they’re made of a very stiff material called beryllium. Which maintains its shape as the temperatures change, but that gets folded. Um, the telescope itself has launched on its side and the sun shield is kind of wrapped around the telescope.


So after launch, we will get rid of the rocket and the rocket fairing. And then in the first, as you mentioned, two to three weeks of the mission will unfold everything. So the first things are like the solar array panel and the communications antenna, so that we can talk to it and it will have power, but then we start to unfold.


The sun shield and the sun shield is pretty carefully folded up and it comes out into the two sides and then we pull it. On the other sides to get it to its diamond shape. And then there were five layers and we separate those layers, uh, so that they are they’re about a foot apart and the heat can kind of get it out from between the layers so that each layer is successively colder.


Uh, when the sun shields all folded out, we’ll then do the two side wings. Of the telescope to make it go from a folded up oval to a, a round telescope shape. And then the last big deployment is the secondary mirror. So the light from the galaxies and stars bounce off the primary mirror. Oh, it’s off a secondary mirror, which is out on a 20 strut structure.


And then it bounces back through the center of the primary mirror, into the instruments, which are behind the mirror, but all of those deployments will take place within the first month. And then we actually have several months to line up all the 18 mirror segments. So that we not would not only have to do the big folding out, but also we have to tweak up the positions very, very accurately so that it appears as a single mirror rather than 18 mirrors, which are slightly different.


So when we first turn on the instruments, I looked through the telescope before this process, we’ll see 18 out of focus, images of what we’re looking at. So we have to measure the positions of each of the mirrors and line them up to a fraction of a wavelength of light so that they all work together. Hmm.


That’s a process that takes a few months. Okay. I, you know, I’ve heard that the telescope is expected to only be utilized for five to 10 years, maybe longer. And we, you know, of course we think of Hubble being active for 30 plus years. And like you said, this isn’t a replacement for Hubble. Is that mainly just because it’s so much farther away and it can’t be service like Hubble has over the years.


Yeah, that’s correct. Um, we can’t get out to where Webb is. For servicing, there’s no capability of that. And because we don’t have the capability of sending astronauts out, it was also not designed to be serviced. So Hubble was designed to be serviced. So everything’s very modular. The instruments can just be slid out and replaced with a new one.


Whereas again, in order to make Webb less massive, it’s much more closely integrated and. The things fit together, much more tightly as for the lifetime of the telescope. There is one thing that gets used up and that is fuel. The observatory to stay in. Its orbit does need to use the rockets once in a while about every, maybe three weeks to maintain its position in the orbit.


Otherwise it would start to drift away and also, um, for maintaining. Uh, what’s called angular momentum. Has the telescope points slightly off in one direction or another from having the big sunshield perfectly lined up with the sun. It builds up some angular momentum as the sunlight bounces off the sun shield and acts as a sort of a solar sail.


And as that angular momentum is built up. Again, periodically every few weeks, we need to use a little fuel to restore it to position, essentially. So we will have a 10 years of fuel on board. And I’ll say that there’s a bit of extra in there kind of just in case. So if we get lucky, we will have a longer than that.


Especially, actually, if we get lucky with the launch, if the launch goes really well, and the rocket puts us in the orbit that we want to be in, we’ll have some of the leftover fuel that was saved to do any corrections. Um, and that translates into additional years, lifetime, but say 10 years. And then, because it cannot be serviced like Hubble.


It will last as long as things keep working makes sense. Well, and then since it’s projected to have a shorter life, will that mean it’ll have more rigorous goals and timelines during its more limited time in service. So we will certainly be doing everything we can to keep it going. One of the things that we would be able to do is managing the pointing so that this angular momentum.


Does it build up too quickly in order to preserve the fuel as well in terms of what the Webb will actually do, but science, it will do that is done by what’s called peer review of proposals. So we’re actually in that process right now. Scientists from around the world. As you mentioned earlier, submitted almost 1200 proposals to use Webb during its first year.


And we have, um, a team of scientists who are reading those proposals and making decisions and recommendations about what are they highest. Priority science goals. What are the highest priority projects that Webb should do? And the first year of observations will be allocated to that process that will, where we’re expecting to get the results of that in early April.


And we’ll find out what, what it will do in its first year, then after launch, when we first start to see some of those. Uh, results and maybe find some things that would be interesting to follow up. We’ll have the call for proposals for the second year and so forth. The time on the telescope will be allocated to this competitive process on an annual basis.


And that ensures. That the most important science is going to be chosen through this process. And, uh, we stay current with not only what Webb itself it’s discovering, but also results that are still coming out of Hubble and, uh, lots of other telescopes on the ground and some of the other space missions as well.


So total commissioning of the telescope projected to be completed about 160 days after launch. And then, you know, like you said, we’ve determined what the goals are and everything, how soon then after that, do you anticipate it’ll be before the public starts to see images and you were talking about the fine, the fine tuning and everything as well.


Right. So, um, I’ll make a spike correction. It’s actually 180 days, six months. And during that time in the last couple of weeks of what’s called commissioning where we’re especially checking out the instruments. There will be some special targets that are chosen to demonstrate the capabilities of the telescope and the instruments, both to the astronomers and to the public.


So while we can hope to get is about six months after launch, we’re going to get the first pictures and those will be released to the public and to the astronomers. And at that point, when things are. You know, when the commissioning is done and we’re ready to go with the science programs, then we’ll just start working our way through the programs that have been selected by this peer review process.


The scheduling depends mostly on where the telescope is and its orbit, what it can look at at any particular time, rather than particularly, you know, what’s the highest priority. Um, the highest priorities will. We can see the whole sky in a year, essentially. Um, so within the first year, um, there’ll be targets throughout the whole sky, but that’s going to be six months after launch.


We’ll start to see pictures. And shortly after that, we’ll start to see a lot of good scientific results. Has the telescope is working its way through the science. That totally makes sense. It depends on where the telescope is. Makes sense. And, uh, you know, given the past delays with the mission and I’m sure probably some struggles with COVID constraints over the last year.


How are things looking for October? Are there any hurdles there? Is it looking pretty good this time I’m watching the schedule. So absolutely it’s looking good. We did have a little bit of a slowdown due to COVID. We, uh, moved the launch date from March to October. That fast change was because basically it meant that we were able to continue with the testing, but it did slow down a bit because of social distancing for the people that were working.


In the clean room. It turns out that we keep the space hardware in a clean room in order to protect the telescope itself from dust and impurities in the air. Um, so when people were working on the hardware, they were wearing masks, they always wore masks. So that’s kind of not the problem, but to get into the clean room.


To go through the process of putting on the gowns and the masks and going through like a, a cleansing air shower way where you get blasted by air to blow any dust off of your clothing. That became a bottleneck because, um, instead of having, you know, maybe six or 10 people changing together, we had to keep them apart, um, social distance as they went through to get into the clean room itself.


So that. We assaulted in this slow down, push the launch date to October. It is looking good. NASA schedules always have a certain amount of contingency, which are days that are in the schedule that, you know, you’re going to use them. You don’t know why. Um, but, uh, you know, whenever something doesn’t quite work optimally in your testing, um, you slow down, you, you figure it out, you can then go start up again and maybe you lost a day or two, but, uh, we still have contingency for, um, October and.


Shipment to the launch site should happen sometime late summer. Um, there’s about three months. I have the launch site itself two to three months and we’ll get down there, get it into the rocket. And then the actual day, we don’t know exactly what day it’s going to be. Um, and of course you need good weather and so forth, but it’s looking good for October.


And that’s, that’s kind of an adventure in itself getting down to South America there. I’ve heard. Yeah. So if it’s going to go by boat through the Panama canal, which is fun at this point with everything on it, it is now too big to fit into the largest cargo airplane. Um, so the final trip is going to be by boat.


That’s excellent. And just a one time, final question, more on a personal note. Uh, as I mentioned in your bio earlier there, you’ve been working on this project for more than 20 years and yourself. Uh, that’s really a long-term relationship kind of, uh, and I assume there must be at least some sentimental feelings about it at this point.


What are your greatest hopes and aspirations for the James Webb space telescope? Absolutely. Yeah. And I’m still excited about the science that we’re going to do. Um, I’m not part of the, the group that’s choosing the proposals, but I got to watch some of the deliberations and there’s, there’s really a lot of exciting stuff.


I’ll say that going into this, uh, It more than 20 years ago, I was most excited about the galaxy evolution work and finding the first galaxies and tracing them from their first formation to the present day. How did the elements build up within the galaxies? Because that’s the research that I do that I’ve done and the research I still have been working with Hubble to do.


Looking forward to Webb getting data about, about galaxy evolution. But I also have to say that, um, with my position in the project, the thing that I’m most excited about is something that I can tell you about right now, because I don’t know what we’re going to see. I’m most excited about the fact that whenever we put up a new capability, that is.


Um, a hundred times better than anything that’s happened before that we’ve done before we find discoveries that we really were not expecting. And so that’s what I’m excited that what we’ll do is something that I don’t, I can’t tell you what it is. Cause I don’t know, but in couple of years from now, will it discover things that we couldn’t predict?


That’s great. It’s all about the unexpected. Well, Jonathan, with launch coming up in about eight months, we know you’re a busy team right now, so thank you so much for taking the time to chat with us today. We’re super excited about all the discoveries that Webb revealed to us, and we wish the entire team there, the best of luck with the mission.


Absolutely. Well, thank you for having me here. Um, I encourage you and your listeners to go to our Website,, and learn more about the mission. Then my pleasure to talk to you sounds great. And this concludes this episode of space foundation space for you podcasts. You can subscribe to this podcast and leave us a review on Podbean, Apple podcasts, Google podcasts, and Spotify.


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Space4U Podcast: Jonathan Gardner – Deputy Senior Project Scientist, James Webb Space Telescope