InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) is a NASA Discovery Program mission that will place a single geophysical lander on Mars to study its deep interior in the core, mantle and crust.

Scientists are trying to understand how all of the rocky planets, such as Earth, were formed and later evolved over time. Mars still has remaining evidence about its rocky planet early development. Earth’s evidence was erased by its internal movements which Mars did not have.

The Red Planet Interior

(Image courtesy of NASA)

Since scientists and geologists know that a planet’s interior retains a signature of its beginnings and evolution, the information inside will provide a signature of the early differentiation processes. The measurements received from these instruments will reveal information about processes that occurred during the initial growth of the planet, the formation and differentiation of its core, crust, and mantle, and subsequent evolution of its interior.

InSight is shown here with sensors fully deployed deeply into the Mars interior (Image courtesy of NASA JPL)

The following items are listed in the figure above and identified below:

Grapple : Mechanism at the end of the IDA that grips the instruments during deployment

Heat Flow Probe : Hammering mechanism that pulls the temperature sensors down into the regolith

HP3 : Heat Flow and Physical Properties Package, the heat flow experiment

IDC : Instrument Deployment Camera, pointable medium-resolution camera

IDA : Instrument Deployment Arm

ICC : Instrument Context Camera, fixed wide-angle camera

Pressure Inlet : Wind-shielded opening for pressure sensor

RISE Antenna : X-band radio antenna for the Rotation and Interior Structure Experiment

SEIS : Seismic Experiment for Interior Structure, the seismometer

Tethers : Cables carrying electrical power, commands and data between the lander and instruments

TWINS : Temperature and Winds for InSight, environmental sensors

UHF Antenna : Antenna used for communication with orbital relay spacecraft

WTS : Wind and Thermal Shield protecting the seismometer from the environment

The original plan was to launch InSight in early 2016 but when a leak in the vacuum environment of the two primary science instruments appeared, due to a defective weld which could not be repaired in time for launch, it subsequently delayed the launch to 2018. (Mars and Earth align ideally only once every 26 months).

The next launch opportunity opens up beginning May 5, 2018 with a proposed landing on November 26, 2018. The craft will operate for a minimum of 728 days or 708 sols (Timekeeping on Mars)

InSight is shown here inside the back shell of the protective aeroshell. The aeroshell or backshell, together with the heat shield (not shown, but would be atop the aeroshell to complete a protective enclosure around the stowed InSight lander. (Image courtesy of NASA JPL)

InSight is shown here as it will look on the Mars surface with its solar arrays fully deployed in this clean room photo at Lockheed Martin Space Systems in Denver, Colorado. (Image courtesy of NASA JPL)

The InSight mission would conduct geophysical exploration of Mars' interior using three instruments:

1. SEIS seismometer monitors seismic activity and tidal displacements

2. RISE : X-band radio Doppler tracking experiment measures rotational variations

3. HP³ : Heat-flow and Physical Properties Probe determines the geothermal heat flux

(Image courtesy of Reference 1)

Seismic Experiment for Interior Structure (SEIS)

SEIS was designed by France’s Centre National d'Études Spatiales (CNES) to measure ground movements as tiny as the diameter of an atom, the instrument must have a vacuum seal around its three main sensors to withstand the harsh conditions of the Martian environment while making ultra-precise measurements.

An overview of the SEIS experiment (Image courtesy of Reference 1)

Seismic Experiment for Interior Structure (SEIS) is one of InSight's two primary science instruments. SEIS, which was provided by the French space agency CNES, is a suite of three seismometers designed to measure “Mars quakes” and other subsurface activity on the Red Planet.

Long-Period Sensors (Image courtesy of NASA JPL)

Short-Period Sensor (Image courtesy NASA JPL)

SEIS has the sensitivity and frequency response of the best Earth-based seismometers. It will be deployed on the Mars surface via a robotic arm. SEIS will be monitored every three hours during one Mars year with no ground-in-the-loop interaction.

RISE location on the InSight lander (Image courtesy of NASA)

RISE will use the lander's X-band radio link for Doppler tracking of the InSight lander's location with an accuracy of a few cm. (Image courtesy of NASA)

The lander will attach itself to the planet in order to enable the measurement of Mars’ rotation, in particular the variations in its rotation axis. The rotational variations are essentially related to the size and state of the core, through its effect on the moment of inertia and damping of the Red Planet Mars.

HP³ has a self-penetrating “mole” that burrows down to five meters below the surface. It trails a tether containing precise temperature sensors every ~10 cm to measure the temperature profile of the subsurface.

Together with measurements of thermal conductivity, HP³ allows a precise determination of the amount of heat escaping from the planet's interior.

The Mars Chip is a microchip about the size of a dime (0.8 cm square). It will carry 826,923 names, submitted by the public online from all over the world over a 22-day period during August and September 2015. It will go to Mars on NASA's InSight lander. This image was taken in November 2015 inside a clean room at Lockheed Martin Space Systems, Denver, where the lander was built. (Image courtesy of NASA)

The Mars Chip will be affixed to the InSight lander deck and will remain on Mars forever.

Placing the Mars Chip on the InSight lander’s deck in a clean room at Lockheed Martin Space Systems in Denver (Image courtesy of NASA JPL)

Engineers at NASA's Jet Propulsion Laboratory, Pasadena, California, etched the names onto a silicon microchip. An electron beam machine at JPL was used which specializes in etching very tiny features (less than 1 micron, or less than one one-thousandth the width of a human hair). NASA JPL uses this machine to make high-precision microdevices in JPL's Microdevices Laboratory.

This technique was also used to write the millions of names that were transported on the Mars Rovers as well as on Mars Orion's first test flight.

References

1 The SEIS experiment on INSIGHT Discovery mission to Mars, Rene Perez, SEIS instrument manager, CNES Ph. Lognonné, S. Deraucourt, IPGP, D. Mimoun, ISAE, K. Hurst, JPL and the SEIS Team, IPPW-10, June 18th 2013, San José

2 Instrument Deployment Testbed: For Planetary Surface Geophysical Exploration, Ashitey Trebi-Ollennu, Arturo L. Rankin, Yang Cheng, Kam S Tso, Robert G Deen, Hrand Aghazarian, Eric A. Kulczycki, Robert G Bonitz, and Leon Alkalai, Jet Propulsion Laboratory, IEEE 2013