InSight landed on Mars to study how all terrestrial planets are made. "InSight" stands for "Interior Exploration using Seismic Investigations, Geodesy and Heat Transport." With a geophysical heat probe and seismometer instruments, the mission seeks answers about the internal layering of Mars for comparison to Earth and the Moon. It will also find out the modern rate of Marsquakes and meteorite impacts.
The mission stands to achieve many firsts. It was the first interplanetary launch from the U.S.'s west coast, from Vandenberg Air Force Base. It has deployed the first seismometer on Mars that is actually in contact with the ground. It will sink a heat probe the deepest into a planet other than Earth, using a self-hammering mole that could penetrate up to 5 meters deep. And it has the first magnetometer ever brought to the Martian surface.
InSight was accompanied to Mars by the first two deep-space CubeSats in the MarCO experimental mission. The twin MarCOs relayed telemetry from InSight to Earth during landing and took photos as they flew past Mars.
NASA / JPL-Caltech / Andrew Bodrov
InSight's self-portrait as a virtual-reality panorama
Get the full VR experience at 360cities.net. This panorama combines 10 exposures taken by InSight's Instrument Deployment Camera (IDC), located on the elbow of its robotic arm, during the Sol 10 of InSight's work on Mars (7 December 2018), its first full self-portrait. InSight took an additional 86 images of the landscape on Sol 14 (11 December 2018), filling in the full 360 degrees. Some parts of the panorama are retouched.
There are two science goals:
Understand the formation and evolution of terrestrial planets through investigation of the interior structure and processes of Mars; and
Determine the present levels of tectonic activity and meteorite-impact activity on Mars.
To accomplish these goals, there are six science objectives, each of which has a set of quantifiable success criteria (for more detail, read the launch press kit):
Determine the thickness and structure of the crust
Determine the composition and structure of the mantle
Positively distinguish between a liquid and solid outer core
Determine the thermal state of the interior
Measure the rate and geographic distribution of seismic activity
Measure the rate of meteorite impacts on the surface
Prime mission end: 24 Nov 2020 (extensions are planned, if the spacecraft is still healthy and budget allows)
NASA / JPL-Caltech / USGS (image); Emily Lakdawalla (map)
Map of all Mars landing sites, failed and successful
This map represents the best known positions for all Mars landers, successful, failed, and planned. Gridlines are spaced 10 degrees apart, with 0 longitude at the center. White text denotes successful missions; gray text, failed missions; blue text, future missions.
The lander is located at 4.502° N, 135.623° E, at an elevation of -2,613.426 meters with respect to the MOLA geoid, within Elysium Planitia. Elysium is a broad, flat, volcanic plain. The very flat, smooth landing site was chosen to minimize the effects that local variations would have on the seismic signals traveling through the ground.
The volcanic activity that formed the Elysium plains occurred in the most recent (Hesperian) age of Mars' geologic history, so it has fewer, smaller craters than most of Mars; in fact, most of the craters in the landing region are secondary craters from the fresh, rayed crater Corinto, located 600 kilometers to the north-northwest of the landing site. Most smaller craters within the landing region don't have large rocks in their rims or ejecta, which provided hope that the heat probe would find a surface that would be easy to penetrate down to the hoped-for 5-meter depth.
Within the landing site, InSight got very lucky. It landed in a hollow, an old impact crater that has been filled with loose material, which the team has named "Homestead hollow." The HP3 team could not have hoped for a more favorable landing site for their "mole."
Location of the InSight landing site within its landing ellipse
Insight landed near the center of its landing ellipse, at the spot marked with a yellow dot. The yellow rectangle marks the location of HiRISE image ESP_036761_1845, taken before landing. The base map is from Mars Odyssey THEMIS.
NASA / JPL-Caltech / map by Phil Stooke
InSight workspace map as of sol 76, after HP3 placement
InSight's design is based on the Phoenix Mars lander, but the solar panels are larger and structurally stronger to support its longer planned mission. Its arm was originally built for the canceled Mars Surveyor lander.
Mass: 694 kg total (79 kg cruise stage, 67 kg propellant, 189 kg aeroshell, 358 kg lander)
Dimensions: deck 1.56m wide and about 0.9 m off the ground after leg compression and sinkage upon landing; solar array wingspan 6m; robotic arm 1.8 m
NASA / JPL-Caltech / Lockheed Martin
Engineering drawing of the InSight lander
In this illustration of the InSight lander's deployed configuration, south would be toward lower right at the Martian work site, with tethered instruments on the ground and the heat probe's mole underground.
Instruments and Experiments
Cameras: The two cameras are modified versions of a Navcam and a Hazcam like those used on Opportunity and Curiosity. The arm camera, also called the Instrument Deployment Camera (IDC), is mounted to the forearm, between elbow and wrist. Its field of view is 45 degrees, like rover Navcams, and it has a pixel size of 0.82 mrad/pixel. The deck camera, called the Instrument Context Camera (ICC), is mounted underneath the front edge of the lander deck. Its field of view is a wide, fish-eye 124 degrees, like rover Hazcams, providing a pixel size of 2.1 mrad/pixel at the center of the image.
Unlike rover Navcams and Hazcams, the InSight cameras have Bayer filters on their detectors, so they produce RGB color photos. They also have new filters that restrict the range of wavelengths they detect to 400-700nm (the rovers have 600-800nm bandpasses). The detectors are much less sensitive to blue light than they are to green or red light, but the InSight team corrects for this before posting the images to the raw images website.
InSight's are single cameras so they can't take simultaneous stereo pairs, but the arm can shift the arm camera's point of view to obtain sequential stereo pairs. The arm will also use its camera to take 360-degree panoramas around the lander, just as rover Navcams do, and can do that from two slightly different points of view to get a stereo panorama.
The Instrument Context Camera (ICC) is at left, mounted to the lander, and the Instrument Deployment Camera (IDC) is at right, mounted to the forearm of the robotic arm. The distance from the IDC to the scoop is about 60 centimeters.
Seismic Experiment for Interior Structure (SEIS): SEIS includes six sensors to measure ground motions. Three measure long-period motions and three measure short-period motions. The sensors are mounted to a precision leveling structure that rests on the ground on three legs. It has a long, flexible tether that connects it to the lander's electronics. A separate Wind and Thermal Shield protects SEIS. The shield has a chain-mail skirt to accommodate an uneven ground surface. Open-access abstract: Lognonné et al. (2019); open-access article: Lognonné et al. (2019); SEIS team website (English)
Heat Flow and Physical Properties Probe (HP3): HP3 (pronounced "H-P-cubed") is a self-hammering mechanical mole designed to burrow as many as 5 meters down into the surface during a period of 30 to 40 days, though it can achieve good results at only 3 meters depth. The mole is 2.7 centimeters wide and 40 centimeters long. It contains sensors and heaters that it can use to measure how readily the Martian ground conducts heat. It has a long tether including 14 temperature sensors that maintain its connection to a support structure that remains on the surface. An engineering tether connects the support structure to the lander electronics. HP3 has half a gigabyte of memory, enough to store the entire load of data expected to be produced during the nominal mission. There is also a radiometer mounted to the lander that separately measures ground-surface temperature using infrared brightness. Open-access abstract: Spohn et al. (2019); open-access article: Spohn et al. (2018)
Rotation and Interior Structure Experiment (RISE): Uses the X-band radio link with Earth to sensitively measure perturbations of Mars' rotation axis over the course of a Mars year, yielding information about the size of the core and how much of it is molten. Open-access article: Folkner et al. (2018)
Auxiliary Payload Sensor Subsystem (APSS): A set of engineering instruments measures magnetic field, wind, and atmospheric temperature and pressure to support the interpretation of ground-motion data from SEIS. The magnetometer is the first ever sent to the surface of Mars. The wind and air temperature sensors, called Temperature and Wind for InSight (TWINS) are refurbished flight spares of the booms on the Rover Environmental Monitoring Station (REMS) instrument on Curiosity. The pressure sensor is inside the lander and is similar to, but more sensitive than, pressure sensors on Viking and Pathfinder. While not technically a science instrument, APSS data will clearly be of value to Mars meteorologists, especially the Curiosity REMS team. Open-access abstract: Banfield et al. (2019); paywalled article: Banfield et al. (2019)
Laser Retroreflector for InSight (LaRRI): LaRRI won't actually be used as part of the InSight mission, but is included on the lander to benefit future science. It is a set of corner-cube reflectors that could be used with an orbiting laser altimeter for very precise distance estimation.
Radio science & communication: InSight carries a helical UHF antenna for data relay to orbiters. It has two medium-gain X-band horn antennas for communication with Earth, one pointed up and east and one pointed up and west. None of the antennas is steerable. The X-band antennas allow InSight to receive commands from Earth.
Electronics and software: InSight's avionics have heritage from MAVEN and GRAIL. There are two main computers for redundancy. Each has a RAD 750 processor operating at 115.5 megahertz, with 64 gigabits of flash memory. The flight software is written in C and C++ within the VxWorks operating system. Individual instruments have their own electronics and flight software, but they send data to the main computer for staging and relay to Earth.
Robotic arm: The Instrument Deployment System (IDS) consists of arm and cameras. The Instrument Deployment Arm (IDA) describes the arm alone. It is 1.8 meters long and has four degrees of freedom (two at the shoulder and one each at wrist and elbow). It was built for the canceled 2001 Surveyor lander (the rest of Surveyor lander was refurbished into the Phoenix lander, which needed a different arm for digging). At the tip of the arm is a grapple with five mechanical fingers, shaped to grasp specially designed, ball-shaped handles on top of the devices that it deploys.
Power: The solar arrays have a combined area of 5.16 square meters and can generate up to 700 watts on a clear day with little accumulated dust. Depending on the weather conditions and dust accumulation, they could generate anywhere from 750 to 3600 watt hours per sol. To conserve power, the spacecraft sleeps most of the time, waking every 3 hours to check health and twice per sol to transfer science data from the instruments.