A New NASA Space Telescope, SPHEREx, Is Moving Ahead
The observatory will map the entire sky to study the rapid expansion of the universe after the big bang, the composition of young planetary systems, and the history of galaxies.
NASA's
upcoming space telescope, the Spectro-Photometer for the History of the
Universe, Epoch of Reionization and Ices Explorer, or SPHEREx, is one step
closer to launch. The mission has officially entered Phase C, in NASA lingo. That
means the agency has approved preliminary design plans for the observatory, and
work can begin on creating a final, detailed design, as well as on building the
hardware and software.
Managed
by NASA's Jet Propulsion Laboratory in Southern California, SPHEREx is scheduled to launch no earlier than June 2024 and no later than April 2025. Its instruments will detect near-infrared
light, or wavelengths several times longer than the light visible to the human
eye. During its two-year mission, it will map the entire sky four times,
creating a massive database of stars, galaxies, nebulas (clouds of gas and dust
in space), and many other celestial objects.
About
the size of a subcompact car, the space telescope will use a technique called
spectroscopy to break near-infrared light into its individual wavelengths, or
colors, just like a prism breaks sunlight into its component colors. Spectroscopy
data can reveal what an object is made of, because individual chemical elements
absorb and radiate specific wavelengths of light. It can also be used to
estimate an object's distance from Earth, which means the SPHEREx map will be
three-dimensional. SPHEREx will be the first NASA mission to build a full-sky spectroscopy
map in near-infrared, and it will observe a total of 102 near-infrared colors.
"That's
like going from black-and-white images to color; it's like going from Kansas to
Oz," said Allen Farrington, the SPHEREx project manager at JPL.
Before
entering Phase C, the SPHEREx team successfully completed a preliminary design
review in October 2020. During this multiday process, the team had to
demonstrate to NASA leadership that they can make their complex, cutting-edge
mission design a reality. Usually, the review is done in-person, but with COVID-19
safety precautions in place, the team had to adjust their presentation to a new
format.
"It
felt like we were producing a movie," said Beth Fabinsky, SPHEREx's deputy
project manager at JPL. "There was just a lot of thought put into the
production value, like making sure the animations we wanted to show would work
over limited bandwidth."
Three
Key Questions
The
SPHEREx science team has three overarching goals. The first is to look for
evidence of something that might have happened less than a billionth of a
billionth of a second after the big bang. In that split second, space itself
may have rapidly expanded in a process scientists call inflation. Such sudden ballooning would have influenced the
distribution of matter in the cosmos, and evidence of that influence would still
be around today. With SPHEREx, scientists will map the position of billions
of galaxies across the universe relative to one another, looking for statistical
patterns caused by inflation. The patterns could help scientists understand the
physics that drove the expansion.
The
second goal is to study the history of galaxy formation, starting with the
first stars to ignite after the big bang and extending to present-day galaxies.
SPHEREx will do this by studying the faint glow created by all the galaxies in
the universe. The glow, which is the reason the night sky is not perfectly dark,
varies through space because galaxies cluster together. By making maps in many
colors, SPHEREx scientists can work out how the light was produced over time
and start to uncover how the first galaxies initially formed stars.
Finally,
scientists will use the SPHEREx map to look for water ice and frozen organic
molecules - the building blocks of life on Earth - around newly forming stars
in our galaxy. Water ice gloms onto dust grains in cold, dense gas clouds throughout
the galaxy. Young stars form inside these clouds, and planets form from disks
of leftover material around those stars. Ices in these disks could seed planets
with water and other organic molecules. In fact, the water in Earth's oceans
most likely began as interstellar ice. Scientists want to know how frequently life-sustaining
materials like water are incorporated into young planetary systems. This will
help them understand how common planetary systems like ours are throughout the
cosmos.
Multiple
mission partners are beginning construction on various hardware and software
components for SPHEREx. The telescope that will collect near-infrared light will
be built by Ball Aerospace in Boulder, Colorado. The infrared cameras that
capture the light will be built by JPL and Caltech (which manages JPL for NASA).
JPL will also build the sun shields that will keep the telescope and cameras
cool, while Ball will build the spacecraft bus, which houses such subsystems as
the power supply and communications equipment. The software that will manage
the mission data and make it accessible to scientists around the world is being
built at IPAC, a science and data center for astrophysics and planetary science
at Caltech. Critical ground support hardware for testing the instruments will
be built by the Korea Astronomy and Space Science Institute (KASI), a science
partner on the mission in Daejeon, South Korea.
The
SPHEREx team is scheduled to spend 29 months building the mission components
before entering the next mission phase, when those components will be brought
together, tested, and launched.
SPHEREx
is managed by JPL for NASA's Astrophysics Division within the Science Mission
Directorate in Washington. The mission's principal investigator, James Bock,
has a joint position between Caltech and JPL. The science analysis of the
SPHEREx data will be conducted by a team of scientists located in 10
institutions across the U.S., and in South-Korea.
For
more information about the SPHEREx mission visit:
https://www.jpl.nasa.gov/missions/spherex/
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