WTS/SEIS
IDA
IDC
Grapple TWINS
RISE antenna
ICC
RISE antenna
Heat flow probe
TWINS
UHF antenna
HP^3
WWW.ASTRONOMY.COM 23
north of Los Angeles and set InSight on
its way to Mars.
Doing the dirty work
The InSight lander carries two cameras
— one mounted below the deck and the
other on the robotic arm — three main
sets of geophysical experiments, and one
set of meteorological instruments. The
geophysical experiments include the
CNES-led seismometer package called
the Seismic Experiment for Interior
Structure (SEIS). The science team
designed it to detect potential mars-
quakes with up to 300 times the sensitiv-
ity of typical terrestrial seismometers,
and to measure the strength of the
magnetic field at Mars’ surface.
The German Aerospace Center built
the Heat Flow and Physical Properties
Package (HP^3 ), which will measure the
planet’s heat flow and conductivity by
hammering a small probe nicknamed
“the mole” as deep as 16 feet (5 meters)
into the subsurface. The JPL-led radio
transmitter experiment, called the
Rotation and Interior Structure
Experiment (RISE), will improve upon
the experiments on previous landers that
helped deduce the nature of the planet’s
interior, including the size of the core.
The Temperature and Winds for InSight
(TWINS) meteorology package consists
of several temperature, pressure, wind
speed, and wind direction sensors placed
at various heights on the lander.
In addition, the lander carries a pas-
sive retroref lector that will allow future
Mars orbiters to shoot laser beams at the
device and accurately track their range to
the surface. Apollo astronauts left similar
devices on the Moon that let scientists
precisely monitor the distance between
Earth and its satellite. Finally, the probe
carries two tiny silicon wafer chips upon
which NASA microscopically etched the
names of more than 2.4 million people
who signed up to have their names sent
to Mars.
During the years prior to launch, the
InSight science and engineering team
worked to identify the perfect landing
site for the mission. This team’s idea of
perfection differed greatly from that of
most previous mission teams, however.
The InSight seismometers and other geo-
physical instruments need to be in good
contact with the planet’s solid surface to
sense seismic waves and to measure heat
f low accurately. This meant avoiding
rocks, loose sand, and piles of dust.
In addition, the heat shield-parachute-
retrorocket landing system, inherited
from the Phoenix lander, did not have
the sophisticated obstacle-avoidance sys-
tems that have allowed other missions to
target specific small areas. In fact, the
mission’s landing ellipse — the region
of uncertainty where the spacecraft was
most likely to set down — stretched a
robust 81 by 17 miles (130 by 27 kilome-
ters). Compare that with the Curiosity
LEFT: InSight’s Instrument Context Camera (ICC), which is mounted below the lander deck, snapped the
probe’s first image of Mars within hours of landing November 26, 2018. The camera’s transparent lens cover
was still in place to protect the lens from dust kicked up during the landing.
RIGHT: InSight flipped open the lens cover on its ICC on November 30. Although some dust still clings to the
lens, this much clearer view reveals a nearby rock at bottom center as well as one of the spacecraft’s foot-
pads at bottom right. The camera’s fisheye lens creates the curved horizon.
Once InSight gets fully
deployed, its instrument
array should look like
this. As of early July, a
problem has kept the
heat flow probe from
reaching its target
depth. See text for
instrument details.
ASTRONOMY: ROEN KELLY,
AFTER NASA/JPL-CALTECH