- [Narrator] This is the Nancy Grace Roman survey telescope
or Roman for short.
NASA is set to launch it into space in 2027.
And this is China's survey telescope Xuntian,
that's set to launch a few years earlier than Roman.
These two telescopes are racing to map the universe
in more detail than ever before,
in the hopes of solving
some of science's greatest mysteries,
like how a little understood force known as dark energy
helped shape our universe.
- Potentially there's even a Nobel Prize there, right,
if you figure out what dark energy is.
- [Narrator] So we unpack the technology and design
behind these telescopes
because the country that can capture the best images
may lead the future of astrophysics research.
- [Reporter] The space shuttle Discovery
with the Hubble Space Telescope, our window on the universe.
- [Narrator] Space telescopes are crucial tools
for avoiding the light pollution and distortion
that limits ground-based telescopes
when they look out at space
from inside the Earth's atmosphere.
An American physicist first proposed
space-based observatories in 1946.
And then about two decades later,
the U.S sent up the first operational space telescope.
The Soviet Union was close behind,
sending up its own first space telescopes
only a few years later.
Since 1990, the field has been dominated by NASA's Hubble,
until the recent launch of the James Webb Space Telescope,
or JWST for short.
- Both Hubble and JWST are telescopes
that look at a very small part of the sky
in a lot of detail.
- [Narrator] Jonathan McDowell is an astrophysicist
at the Harvard-Smithsonian Center for Astrophysics.
He's worked with NASA
and has been monitoring space activities and satellites
for three decades.
- They aren't used to, kind of, look around and go,
oh, I wonder if we'll see something here.
You look at something you already know is there,
and you stare at it in detail.
- [Narrator] This is where the race
to build the next generation of telescopes comes in.
With survey telescopes that can map out
large areas of the sky.
NASA's Nancy Grace Roman is named after
the agency's first chief astronomer.
Xuntian is China's first ever space telescope
and translates to "survey of the heavens" in Chinese.
- Let's make no bones about it.
They're both fantastic and amazing facilities.
- [Narrator] Quentin Parker is an astrophysicist
and the Director of the Laboratory for Space Research
at the University of Hong Kong.
He's been observing the rapid acceleration
of China's space program for over the past decade.
- You know, surveys, by their nature,
throw up incredible things.
You don't know what they're going to find.
- [Narrator] Both telescopes are designed
to learn more about dark energy,
a mysterious pressure that scientists believe
is responsible for the accelerating expansion
of the universe and the galaxies inside it.
- That will let us understand how our galaxy evolved,
how the chemical elements in our galaxy evolved,
how we got here.
- [Narrator] But there are currently no telescopes
that can detect dark energy,
even though scientists say it makes up
around 70% of the total energy of the universe.
So the goal is for scientists
to use Xuntian and Roman to uncover dark energy's secrets.
- We're not collecting signatures from dark energy directly.
We're looking at the way that it's interacting
with things that we can measure.
- [Narrator] So U.S. and Chinese researchers are racing
to build telescopes that can answer the same question,
but each with a different design.
One difference is in the telescopes' mirrors.
- So if you throw a certain amount of light
at the telescope, right,
some fraction of it is reflected by the mirror.
And some fraction of that is captured by the camera.
- [Narrator] Roman's mirror is larger than Xuntian's,
which means it will be able to capture more light,
giving the final image more detail.
But even though Xuntian's mirror is smaller in diameter,
it has a field of view that's more than three times wider.
This means it'll be able to image more of the sky
over the course of its mission than Roman.
While Xuntian may have an edge on image size,
the quality depends on another important part
of the telescope, the sensor module.
The sensor reads and processes the light
captured by the mirror,
and sends back information to Earth
for scientists to turn into amazing images,
like these ones from the James Webb telescope.
So having a less powerful sensor can create problems
for the images that are produced.
- You are likely to get images with more artifacts in them,
with more noise, with less sensitivity.
It can't see quite as faint stars, things like that.
- [Narrator] McDowell says NASA's six decades of experience
creating sensors that work
under the extreme conditions of space
give it an advantage over China's younger space agency.
- The challenge for China is,
can they match the sort of semiconductor technology aspects
of NASA's cameras.
- [Narrator] By having more experience with telescopes,
NASA can also be more ambitious
about how far it sends Roman.
The telescope will orbit the sun from a distance
of about 1 million miles from Earth.
That means Roman will be able to operate
without constant changes in light and temperature.
And NASA says that allows the telescope
to collect data constantly.
Xuntian, on the other hand, will stay close to the Earth
and therefore be regularly blocked as it orbits,
limiting the amount of time it can spend collecting data.
But being that far away also means Roman can't be repaired
if anything goes wrong.
Xuntian will be near the Chinese space station,
giving scientists on board access to the telescope,
if needed.
- You can actually, not only can you repair it,
if it gets damaged,
or if the solar panels gets damaged,
or if something goes wrong,
you can upgrade it.
You can replace the camera.
You can put on new filters, new instrumentation,
give it a new lease of life,
keep it going for longer.
- [Narrator] However, what could be
the most important advantage is Xuntian's launch date.
China's space agency says it's going up in 2023,
giving it about a four year head start on Roman.
- They may steal some of the thunder
from what the Roman telescope would've done.
- [Narrator] NASA said in a statement
that Xuntian's observations will complement its mission.
And Roman has unique capabilities
for the study of dark energy.
China's space administration didn't respond
to a request for comment
on Xuntian's launch schedule and design.
Scientists say both telescopes will play a significant role
in learning more about the origins of the universe.
- There's a lot of international recognition
if you, you know, if you start to elucidate
what's going on in the early universe
- [Narrator] But only one country can lay claim
to being the first to make the biggest discoveries
in astrophysics.
(twinkling music)