As NASA's James Webb Space Telescope moves through the final phases of
commissioning its science instruments, we have also begun working on
technical operations of the observatory. While the telescope moves through
space, it will constantly find distant stars and galaxies and point at them
with extreme precision to acquire images and spectra. However, we also plan
to observe planets and their satellites, asteroids, and comets in our solar
system, which move across the background stars of our galaxy.
Webb needs to be able to lock on to these objects and track them with
sufficient precision to obtain images and spectra. The Webb team recently
completed the first test to track a moving object. The test verified that
Webb could conduct moving target science. As we move forward through
commissioning, we will test other objects moving at various speeds to verify
we can study objects with Webb that move throughout the solar system.
Today, we asked Heidi Hammel, Webb interdisciplinary scientist for solar
system observations, to tell us about her plans for studying Earth's nearest
neighbors:
"I am really excited about Webb's upcoming first year of science operations.
I lead a team of equally excited astronomers eager to begin downloading
data. Webb can detect the faint light of the earliest galaxies, but my team
will be observing much closer to home. They will use Webb to unravel some of
the mysteries that abound in our own solar system.
"One of the questions I get asked frequently is why we need a powerful
telescope like Webb to study our nearby solar system. We planetary
scientists use telescopes to complement our in situ missions (missions that
we send to fly by, orbit, or land on objects). One example of this is how
Hubble was used to find the post-Pluto target for the New Horizons mission,
Arrokoth. We also use telescopes when we don't have in situ missions
planned—like for the distant ice giants Uranus and Neptune or to make
measurements of large populations of objects, such as hundreds of asteroids
or Kuiper Belt Objects (small ice worlds beyond the orbits of Neptune,
including Pluto), since we can only send missions to just a few of these.
"The Webb team has already used an asteroid within our solar system to run
engineering tests of the 'moving target' (MT) capability. The engineering
team tested this capability on a small asteroid in the Main Belt: 6481
Tenzing, named after Tenzing Norgay, the famous Tibetan mountain guide who
was one of the first people to reach the summit of Mount Everest. Bryan
Holler, at the Space Telescope Science Institute, had a choice of about 40
possible asteroids to test the MT tracking, but, as he told our team, 'Since
the objects were all virtually identical otherwise, picking the one with a
name linked to success seemed like a no-brainer.' We like that sort of
thing.
"My role with Webb as an 'Interdisciplinary Scientist' means that my program
uses all of the capabilities of this forefront telescope. We need all of
them to truly understand the solar system (and the universe).
"Our solar system has far more mysteries than my team had time to solve. Our
programs will observe objects across the solar system: We will image the
giant planets and Saturn's rings; explore many Kuiper Belt Objects; analyze
the atmosphere of Mars; execute detailed studies of Titan; and much more.
There are also other teams planning observations; in its first year, 7% of
Webb's time will be focused on objects within our solar system.
"One exciting and challenging program we plan to do is observe ocean worlds.
There's evidence from the Hubble Space Telescope that Jupiter's moon Europa
has sporadic plumes of water-rich material. We plan to take high-resolution
imagery of Europa to study its surface and search for plume activity and
active geologic processes. If we locate a plume, we will use Webb's
spectroscopy to analyze the plume's composition.
"I have a soft spot in my heart for Uranus and Neptune. Indeed, it was the
lack of a mission to these very distant worlds that got me involved in Webb
so many decades ago. The Uranus team hopes to definitively link the
chemistry and dynamics of the upper atmosphere (detectable with Webb) to the
deeper atmosphere that we have been studying with other facilities over many
decades. I've spent the past 30 years using the biggest and best telescopes
humanity has ever built to study these ice giants, and we will now add Webb
to that list.
"We have been planning for Webb observations for over twenty years, and that
has gone into overdrive now that we are launched, deployed, and focused.
I'll note that nearly all of my team's solar system data will be freely
available to the broad planetary science community immediately. I made that
choice to enable more science discoveries with Webb in future proposals.
"I am gratified to have been able to work with the team for all this time,
and I especially want to give a shout out to the thousands of people who
collectively have enabled this amazing facility for the astrophysics and
planetary communities. Thank you; ad astra."
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Space & Astrophysics