The Hubble Space Telescope has been in space
for 28 years, producing some of the most beautiful and scientifically important images of the
cosmos that humanity has ever taken. But let’s face it, Hubble is getting old,
and it probably won’t be with us for too much longer. NASA’s James Webb Space Telescope is in
the final stages of testing, and WFIRST is waiting in the wings. You’ll be glad to know there are even more
space telescopes in the works, a set of four powerful instruments in design right now,
which will be part of the next Decadal Survey, and helping to answer the most fundamental
questions about the cosmos. I know, I know, the James Webb Space Telescope
hasn’t even reached space yet, and there could still be more delays as it goes through
its current round of tests. At the time I’m recording this video, it’s
looking like May 2020, but come on, you know there’ll be delays. And then there’s WFIRST, the wide angle
infrared space telescope that’s actually made of an old Hubble class telescope that
the National Reconnaissance Office didn’t need any more. The White House wants to cancel it, Congress
saved it, and now NASA is getting parts of it constructed. Assuming it doesn’t run into more delays,
we’re looking at a launch in the mid-2020s. I’ve actually done an episode about supertelescopes,
and talked about James Webb and WFIRST, so if you want to learn more about those observatories,
check that out first. Today we’re going to go further into the
future, to look at the next next generation telescopes. The ones that could be launched after the
telescope that gets launched after the telescope that comes next. Before I dig into these missions, I need to
talk about the Decadal Survey. This is a report created by the US National
Academy of Sciences for Congress and NASA. It’s essentially a wishlist from scientists
to NASA, defining the biggest questions they have in their field of science. This allows Congress to assign budgets and
NASA to develop mission ideas that will help fulfill as many of these science goals as
possible. These surveys are done once every decade,
bringing together committees in Earth science, planetary science, and astrophysics. They pitch ideas, argue, vote and eventually
agree on a set of recommendations which will define science priorities over the next decade. We’re currently in the 2013-2022 Decadal
Survey period, so in just a few years, the next survey will be due, and define the missions
from 2023-2032. I know, that really sounds like the distant
future, but time’s actually running out to get the band back together. If you’re interested, I’ll put a link
to the last Decadal Survey, it’s a fascinating document and you’ll get a better sense of
how missions come together. We’re still a few years away from the final
document, but serious proposals are in the planning stages for next generation space
telescopes, and they are awesome. Let’s talk about them. The first mission we’ll look at is HabEx,
or the Habitable Exoplanet Imaging Mission. This is a spacecraft that will directly photograph
planets orbiting other stars. It’ll be targeting all kinds of planets,
from hot Jupiters to super Earths, but its primary target will be to photograph Earth-like
exoplanets and measure their atmospheres. In other words, HabEx is going to try and
detect signals of life in planets orbiting other stars. In order to get this done, HabEx needs to
block the light from the star, so that much fainter planets nearby can be revealed. It’ll have one and maybe two ways to do
this. The first is using a coronagraph. This is a tiny dot that sits inside the telescope
itself, which is positioned in front of the star and blocks its light. The remaining light passing through the telescope
comes from fainter objects around the star and can be imaged by the instrument’s sensor. The telescope has a special deformable mirror
that can be tweaked and tuned until the fainter planets come into view. Here’s an example of a coronagraph in use,
on the European Southern Observatory’s Very Large Telescope. The central star is hidden, revealing the
dimmer dust disk around it. Here’s a direct image of a brown dwarf orbiting
a star. And this is one of the most dramatic videos
I think I’ve ever seen, with 4 Jupiter-sized worlds orbiting around the star HR 8799. It’s a bit of a trick, the researchers animated
the motion of the planets in between observations, but still, wow. The second method of blocking the light will
be to use a Starshade. This is a completely separate spacecraft that
looks like a pinwheel. It flies tens of thousands of kilometers away
from the telescope, and when it’s positioned perfectly, it blocks the light from the central
star, while allowing light from the planets to leak around the edges. The trick with a Starshade is those petals,
which create a softer edge so the light waves from the fainter planet is less bent. This creates a very dark shadow that should
have the best chance at revealing planets. Unlike most missions, Starshades like this
can be used with any observatory in space. So, Hubble, James Webb or any other observatory
could take advantage of this instrument. We’ve always complained about how we can
only see a fraction of the planets out there using the transit or radial velocity method
because of how things line up. But with a mission like HabEx, planets can
be seen direction, in any configuration. In addition to this primary mission, HabEx
will also be used for a variety of astrophysics, like observing the early Universe, and studying
the chemicals of the biggest stars before and after they explode as supernovae. Next up, Lynx, which will be NASA’s next
generation X-ray telescope. Surprisingly, it’s not an acronym, it’s
just named after the animal. In various cultures Lynxes were thought to
have the supernatural ability to see the true nature of things. X-rays are at the higher end of the electromagnetic
spectrum, and they’re blocked by the Earth’s atmosphere, so you need a space telescope
to be able to see them. Right now, NASA has its Chandra X-ray Observatory,
and ESA is working on its ATHENA mission, due for launch in 2028. Lynx will act as a partner to the James Webb
Space Telescope, peering out to the edge of the observable Universe, revealing the first
generations of supermassive black holes, and helping to chart their formation and mergers
over time. It’ll see radiation coming from the hot
gas from the early cosmic web, as the first galaxies were coming together. And then it’ll be used to examine the kinds
of objects Chandra, XMM Newton and other X-ray observatories focus on: pulsars, galaxy collisions,
collapsars, supernovae, black holes, and more. Even normal stars can give off X-ray flares
that tell us more about them. The vast majority of the Universe’s matter
is located in clouds of gas as hot as a million Kelvin. If you want to see the Universe as it truly
is, you want to look at it in X-rays. X-ray telescopes are different from visible
light observatories like Hubble. You can’t just have a mirror that bounces
X-rays. Instead, you use grazing-incidence mirrors
which can slightly redirect photons that hit them, funneling them down to a detector. With a 3 meter outer mirror, the starting
part of the funnel, it’ll provide 50-100 times the sensitivity with 16 times the field
of view, gathering photons at 800 times the speed of Chandra. I’m not sure what else to say. It’ll be a monster X-ray observatory. Trust me, astronomers think this is a very
good idea. Next, the Origins Space Telescope or OST. Like James Webb, and the Spitzer Space Telescope,
OST is going to be an infrared telescope, designed to observe some of the coolest objects
in the Universe. But it’s going to be even bigger. While James Webb has a primary mirror 6.5
meters across, the OST mirror will be 9.1 meters across. Imagine a telescope almost as big as the largest
ground telescopes on Earth, but out in space. In space. It won’t just be big, it’ll be cold. NASA was able to cool down Spitzer to just
5 Kelvin - that’s 5 degrees above absolute zero, and just a little warmer than the background
temperature of the Universe. They’re planning to get Origins down to
4 Kelvin. It doesn’t sound like much, but it’s a
huge engineering challenge. Instead of just cooling the spacecraft with
liquid helium like they did with Spitzer, they’ll need to take the heat out in stages,
with reflectors, radiators, and finally a cryocooler around the instruments themselves. With a huge, cold infrared telescope, Origins
will push beyond James Webb’s view of the formation of the first galaxies. It’ll look to the era when the first stars
were forming, a time that astronomers call the Dark Ages. It’ll see the formation of planetary systems,
dust disks and directly observe the atmospheres of other planets looking for biosignatures,
evidence of life out there. Three exciting missions, that’ll push our
knowledge of the Universe forward. But I’ve saved the biggest, most ambitious
telescope for last. And we’ll talk about that in a second, but
first I’d like to thank: The Amazing Thunderchild
Bryan Alvarez Grant Lanning
Thomas Wippich Torben Frylund
Eric M And the rest of our 823 patrons for their
generous support. If you love what we’re doing and want to
get in on the action, head over to patreon.com/universetoday. All right, I’ve saved the best for last:
LUVOIR, or the Large UV/Optical/IR Surveyor. James Webb is going to be a powerful telescope,
but it’s an infrared instrument designed to look at cooler objects in the Universe,
like red-shifted galaxies at the beginning of time, or newly forming planetary systems. The Origins Space Telescope will be a better
version of James Webb. LUVOIR will be the true successor to the Hubble
Space Telescope. It’ll be a huge instrument capable of seeing
in infrared, visible light and ultraviolet. There are two designs in the works. One which is 8-meters across and could launch
on a heavy-lift vehicle like the Falcon Heavy. And another design that would use the Space
Launch System that measures 15-meters across. That’s 50% bigger than the biggest Earth-based
telescope. Remember, Hubble is only 2.6 meters. It’ll have a wide field of view and a suite
of filters and instruments that astronomers can use to observe whatever they want. It’ll be equipped with a coronograph like
we talked about earlier, to directly observe planets and obscure their stars, a spectrograph
to figure out what chemicals are present in exoplanet atmospheres, and more. LUVOIR will be a general purpose instrument,
which astronomers will use to make discoveries across the fields of astrophysics and planetary
science. But some of its capabilities will include:
directly observing exoplanets and searching for biosignatures, categorizing all the different
kinds of exoplanets out there, from hot Jupiters to super Earths. It’ll be able to observe objects within
the Solar System better than anything else - if we don’t have a spacecraft there, LUVOIR
will be a pretty good view. For example, here’s a view of Enceladus
from Hubble, compared to the view from LUVOIR. It will be able to look out anywhere in the
Universe, to see much smaller structures than Hubble. It’ll see the first galaxies, first stars,
and help measure the concentrations of dark matter across the Universe. Astronomers still don’t fully understand
what happens when stars gather enough mass to ignite. LUVOIR will look into star forming regions,
peer through the gas and dust and see the earliest moments of star formation as well
as the planets orbiting them. Have I got you totally and completely excited
about the future of astronomy? Good. But here’s comes the bad news. There’s almost no chance reality will match
this fantasy. Earlier this month NASA announced that mission
planners working on these space telescopes will need to limit their budgets to between
three and five billion dollars. Until now, planners didn’t have any guidelines,
they were to just design instruments that could get the science done. Engineers had been working on mission plans
that could easily cross $5 billion for HabEx, Lynx and OST, and were considering a much
larger $20 billion for LUVOIR. Even though Congress has been pushing for
surprisingly big budgets for NASA, the space agency wants its planners to be conservative. And when you consider just how over budget
and late James Webb has become, it’s not entirely surprising. James Webb was originally supposed to cost
between one and three point five billion dollars and launch between 2007 and 2011. Now it looks like 2020 for a launch, the costs
have broken past a Congress mandated $8.8 billion budget, and it’s clear there’s
still a lot of work to be done. In a recent shake test, engineers found washers
and screws that had shaken out of the telescope. This isn’t like an IKEA shelf with leftover
parts. These pieces are important. Even though it’s been saved from the chopping
block, the WFIRST Telescope is estimated to be $3.9 billion, up from its original $2 billion
budget. One, two or maybe even all of these telescopes
will eventually get built. This is what the scientists think are most
important to make the next discoveries in astronomy, but get ready for budget battles,
cost overruns and stretching timelines. We’ll know better when all the studies come
together in 2019. It would take some kind of engineering miracle
to have all four telescopes come together, on time and on budget, to blast to space together
in 2035. I’ll keep you updated. What do you think? Which of these telescopes is most exciting
to you? Let me know your thoughts in the comments. Once a week I gather up all my space news
into a single email newsletter and send it out. It’s got pictures, brief highlights about
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Habex is going to be the most amazing thing Humanity has built for Space in my opinion.
Do a big, general purpose design, but build 5-10 of them, keep it simple, and don't let the usual suspects and their cost/time blow outs anywhere near it. Since most of the cost is in the design, doing multiple copies shouldn't be significantly more expensive than one. Then place them at different spots both around the earth, and other planets, getting the advantage of two views of the same objects at the same time. With the cost of launch (outside NASA) coming way down, you can put them up for little money, and shift them around the solar system.
Target to have them in place before 2030 or maybe even 2025. Go fast and get them inside the political time horizons.
Habex sounds like the 'safest' and 'cheapest' option with internal coronagraph, so will probably be the only project selected for Modern-NASA.