WWW.ASTRONOMY.COM 27InSight sets
up shop on
Mars
NASA’s InSight mission —
short for Interior Exploration using
Seismic Investigations, Geodesy,
and Heat Transport — landed on
Mars November 26, 2018, charged
with a unique task: explore the
Red Planet’s interior. Its cameras
and weather monitoring instru-
ments immediately began send-
ing information back, while the
lander took several weeks to set
up shop in Elysium Planitia near
the planet’s equator.
In the ensuing months, the
spacecraft has operated flaw-
lessly, says Bruce Banerdt, InSight’s
principal investigator and princi-
pal research scientist. So has the
mission’s Seismic Experiment for
Interior Structure (SEIS), which
detected its first small marsquake
April 6, 2019. Since then, SEIS has
recorded several events each
week, with more than a dozen that
researchers believe are real quakes.
Oddly, most of the observed mars-
quakes are small, with few of the
larger events that the team hadexpected. “We don’t know yet
whether that’s just the statistics,
or whether it just means that Mars
has a little bit different distribu-
tion of the way that it releases its
seismic energy than Earth and the
Moon,” Banerdt says. If it’s the lat-
ter, he says, “that’s really an excit-
ing possibility, that we’re going to
learn something fundamentally
new about the way planets work
in a physical sense.” Many of the
events also have strange signals
not reminiscent of earth- or moon-
quakes, which is both an unex-
pected and exciting find, he says.
InSight’s radio science and
meteorology packages are also
returning valuable data, while the
craft’s cameras have allowed addi-
tional science, including geologi-
cal studies.
There has been one snag. On
February 28, 2019, the Heat Flow
and Physical Properties Package,
HP^3 , released its self-hammering
probe, the “mole,” into the soil.
Meant to burrow as deep as
16 feet (5 m) and directly measure
the planet’s subsurface tempera-
ture, the mole instead got stuck
just hours later, reaching a depth
of only 14 inches (35 centimeters).
“The layers of dirt just below thesurface appear to be somewhat
cemented. They’re stronger than
we expected,” Banerdt says.
Although the setback has been
disappointing, the team devised
a plan to get the mole mov-
ing again. On October 17, NASA
announced that pressing InSight’s
scoop against the mole had
increased friction on the probe
enough to get it moving again.
Since October 8, the agency said,
the mole had dug another ¾ inch
(2 cm), indicating to engineers
there were no rocks halting its
progress and renewing hope that
the experiment could proceed.
“For the most part, things
are going extremely smoothly,”
Banerdt says of the mission. “The
thing about this mission is it takes
patience. Everything that we do
on this mission is accumulating
data and the more we get, the
better our science is.”
InSight is definitely off to a
good start. The initial mission
duration is 708 sols, or nearly two
Earth years. After that, Banerdt
says, the team will petition NASA
for an extension. So it’s a good
bet that InSight will continue to
appear in the news for some time
to come.first sample of material from beneath the
surface of an asteroid. “The Japanese
have really made exploration history with
this mission,” says Deborah Domingue,
senior scientist and deputy director at
the Planetary Science Institute and
Hayabusa2 participating scientist. “This
is not an easy engineering project. They
made it look easy and it’s not.”
Once those samples are brought to
Earth, she says, the science return will be
enormous. Not only will researchers get a
look at how the asteroid’s surface layer has
been processed by space weathering such
as radiation and impacts, but they will
also get a peek at undisturbed, unpro-
cessed material from within the man-
made crater. By combining those samples
with remote sensing data such as images
and spectra taken by the spacecraft,
Domingue says, researchers will be able to
extrapolate what they learn from the sam-
ples to other places on Ryugu. And that
will teach scientists how space changes the
surface of an asteroid over time.
The remote sensing data have already
given scientists plenty to work with,
including several indications that the
2,900-foot-wide (880 m) Ryugu formed
from debris that broke off a larger parent
asteroid long ago. It’s surprisingly dark
and dry, devoid of hydrated minerals,
indicating its parent was likely also water-
poor. That has implications for how Earth
did — or didn’t — get water during the
planet’s formation, as scientists believe
asteroids may have delivered much of it.
Hayabusa2 will remain at Ryugu until
December, when it will turn and head for
home with its precious cargo.5
An image from just a few meters above the surface
of Ryugu shows its strange, rocky terrain.
Researchers had expected areas of finer material,
but none exist on the asteroid. JAUMANN ET AL., SCIENCE 2019