InSight

The Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) mission is a robotic lander designed to study the deep interior of the planet Mars. It was manufactured by Lockheed Martin Space Systems, is managed by NASA's Jet Propulsion Laboratory, and most of its scientific instruments were built by European agencies. The mission launched on 5 May 2018 at 11:05 UTC aboard an Atlas V-401 rocket and successfully landed at Elysium Planitia on Mars on 26 November 2018 at 19:52:59 UTC. "InSight" traveled during its journey. As of , , "InSight" has been active on Mars for sols ( days; "").
"InSight" objectives are to place a seismometer, called SEIS, on the surface of Mars to measure seismic activity and provide accurate 3D models of the planet's interior; and measure internal heat flow using a heat probe called HP3 to study Mars' early geological evolution. This could bring a new understanding of how the Solar System's terrestrial planets – Mercury, Venus, Earth, Mars – and Earth's Moon form and evolve.
The lander was originally planned for launch in March 2016. An instrument problem delayed the launch beyond the 2016 launch window. NASA officials rescheduled the "InSight" launch to May 2018 and during the wait the instrument was repaired. This increased the total cost from to $830 million. As of January 2021, "InSight" is approved for extended operations through December 2022.
History.
Discovery Program selection.
"InSight" was initially known as GEMS (Geophysical Monitoring Station), but its name was changed in early 2012 following a request by NASA. Out of 28 proposals from 2010, it was one of the three Discovery Program finalists receiving $3 million in May 2011 to develop a detailed concept study. In August 2012, "InSight" was selected for development and launch. Managed by NASA's Jet Propulsion Laboratory (JPL) with participation from scientists from several countries, the mission was cost-capped at $425 million, not including launch vehicle funding.
By reusing the landing system designed for the Mars "Phoenix" lander, which successfully landed on Mars in 2008, mission costs and risks were reduced.
Schedule issues.
Lockheed Martin began construction of the lander on 19 May 2014, with general testing starting on 27 May 2015.
A persistent vacuum leak in the CNES-supplied seismometer known as the Seismic Experiment for Interior Structure (SEIS) led NASA to postpone the planned launch in March 2016 to May 2018. When "InSight" was delayed, the rest of the spacecraft was returned to Lockheed Martin's factory in Colorado for storage, and the Atlas V rocket intended to launch the spacecraft was reassigned to the "WorldView-4" mission.
On 9 March 2016, NASA officials announced that "InSight" would be delayed until the 2018 launch window at an estimated cost of $150 million. The spacecraft was rescheduled to launch on 5 May 2018 for a Mars landing on 26 November at 15:00. The flight plan remained unchanged with launch using an Atlas V rocket from Vandenberg Air Force Base in California. NASA's Jet Propulsion Laboratory was tasked with redesigning and building a new vacuum enclosure for the SEIS instrument, while CNES conducted instrument integration and testing.
On 22 November 2017, "InSight" completed testing in a thermal vacuum, also known as TVAC testing, where the spacecraft is put in simulated space conditions with reduced pressure and various thermal loads. On 23 January 2018, after a long storage, its solar panels were once again deployed and tested, and a second silicon chip containing 1.6 million names from the public was added to the lander.
Energy crisis.
The InSight lander, powered by solar panels and batteries, relies on periodic wind gusts called "cleaning events" to reduce dust accumulation on the panels. Elysium Planitia, the landing site of InSight, has experienced fewer cleaning events than needed to keep the science operations powered. In February 2021, at the start of the Martian winter, InSight's solar cells were producing 27% of capacity due to a thick covering of dust on the panels. At that time NASA began the process of putting the lander into hibernation mode, shutting down data-gathering instruments on a schedule to conserve enough power to keep the lander electronics warm through the Martian winter. NASA hopes that weather conditions will improve and allow InSight to store enough energy to come out of hibernation in July 2021. 
Science background.
Seismic vibrations.
Both "Viking" spacecraft carried seismometers mounted on their landers, and in 1976 picked up vibrations from various operations of the lander and from the wind. However, the "Viking 1" lander's seismometer did not deploy properly and did not unlock; the locked seismometer could not operate.
The Viking 2 seismometer did unlock, and was able to vibrate and return data to Earth. One problem was accounting for other data. On Sol 80, the Viking 2 seismometer detected an event. No wind data were recorded at the same time, so it was not possible to determine whether the data indicated a seismic event or wind gust. Other lacking data would have been useful to rule out other sources of vibrations. Two other problems were the location of the lander and that a certain level of wind on Mars caused a loss of sensitivity for the Viking 2 seismometer. InSight has many other sensors, is placed directly on the surface, and also has a windshield.
Despite the difficulties, the Viking 2 seismometer readings were used to estimate a Martian geological crust thickness between at the "Viking 2" lander site. The "Viking 2" seismometer did detect vibrations from Mars winds complementing the meteorology results. There was the aforementioned candidate for a possible marsquake, but is not particularly definitive. The wind data did prove useful in its own right, and despite the limitations of the data, widespread and large marsquakes were not detected.
Seismometers were also left on the Moon, starting with Apollo 11 in 1969, and also by Apollo 12, 14, 15 and 16 missions and provided many insights into lunar seismology, including the discovery of moonquakes. The Apollo seismic network, which was operated until 1977, detected at least 28 moonquakes up to 5.5 on the Richter scale.
One of the aspects of the InSight mission is to compare the Earth, Moon, and Mars seismic data to learn more.
Planetary nutation.
Radio Doppler measurements were taken with "Viking" and twenty years later with "Mars Pathfinder", and in each case the axis of rotation of Mars was estimated. By combining this data the core size was constrained, because the change in axis of rotation over 20 years allowed a precession rate and from that the planet's moment of inertia to be estimated. "InSight" measurements of crust thickness, mantle viscosity, core radius and density, and seismic activity should result in a three- to tenfold increase in accuracy compared to current data.
Objectives.
The "InSight" mission placed a single stationary lander on Mars to study its deep interior and address a fundamental issue of planetary and Solar System science: understanding the processes that shaped the rocky planets of the inner Solar System (including Earth) more than four billion years ago.
"InSight" primary objective is to study the earliest evolutionary processes that shaped Mars. By studying the size, thickness, density and overall structure of Mars' core, mantle and crust, as well as the rate at which heat escapes from the planet's interior, "InSight" will provide a glimpse into the evolutionary processes of all of the rocky planets in the inner Solar System. The rocky inner planets share a common ancestry that begins with accretion. As the body increases in size, its interior heats up and evolves to become a terrestrial planet, containing a core, mantle and crust. Despite this common ancestry, each of the terrestrial planets is later shaped and molded through the poorly understood process of differentiation. "InSight" mission's goal is to improve the understanding of this process and, by extension, terrestrial evolution, by measuring the planetary building blocks shaped by this differentiation: a terrestrial planet's core, mantle and crust.
The mission will determine if there is any seismic activity, measure the rate of heat flow from the interior, estimate the size of Mars' core and whether the core is liquid or solid. This data would be the first of its kind for Mars. It is also expected that frequent meteor airbursts (10–200 detectable events per year for "InSight") will provide additional seismo-acoustic signals to probe the interior of Mars. The mission's secondary objective is to conduct an in-depth study of geophysics, tectonic activity and the effect of meteorite impacts on Mars, which could provide knowledge about such processes on Earth. Measurements of crust thickness, mantle viscosity, core radius and density, and seismic activity should result in a three- to tenfold increase in accuracy compared to current data. This is the first time a robotic lander dug this deep into the martian crust.
In terms of fundamental processes shaping planetary formation, it is thought that Mars contains the most in-depth and accurate historical record, because it is big enough to have undergone the earliest accretion and internal heating processes that shaped the terrestrial planets, but is small enough to have retained signs of those processes. The science phase is expected to last for two years.
In March 2021, NASA reported, based on measurements of over 500 Marsquakes by the "InSight" lander on the planet Mars, that the core of Mars is between , about half the size of the core of Earth, and significantly smaller — suggesting a core of lighter elements — than thought earlier.
Design.
The mission further develops a design based on the 2008 "Phoenix" Mars lander. Because "InSight" is powered by solar panels, it landed near the equator to enable maximum power for a projected lifetime of two years (1 Martian year). The mission includes two relay microsatellites called Mars Cube One (MarCO) that launched with "InSight" but were flying in formation with "InSight" to Mars.
Three major aspects to the InSight spacecraft are the "cruise stage", the "entry, descent, and landing system", and the "lander".
Lander specifications.
Power.
Power is generated by two round solar panels, each in diameter when unfurled, and consisting of SolAero ZTJ triple-junction solar cells made of InGaP/InGaAs/Ge arranged on Orbital ATK UltraFlex arrays. After touchdown on the Martian surface, the arrays are deployed by opening like a folding fan.
Payload.
"InSight" lander payload has a total mass of , including science instruments and support systems such as the Auxiliary Payload Sensor Suite, cameras, the instrument deployment system, and a laser retroreflector.
"InSight" performs three major experiments using SEIS, HP3 and RISE. SEIS is a very sensitive seismometer, measuring vibrations; HP3 involves a burrowing probe to measure the thermal properties of the subsurface. RISE uses the radio communication equipment on the lander and on Earth to measure the overall movement of planet Mars that could reveal the size and density of its core.
The two relay 6U cubesats were part of the overall InSight program, and were launched at the same time as the lander but they were attached to the centaur upper stage (InSight's second stage in the launch). They were ejected from the stage after launch and coasted to Mars independent of the main InSight cruise stage with the lander.
Journey to Mars.
Launch.
On 28 February 2018, "InSight" was shipped via C-17 cargo aircraft from the Lockheed Martin Space Systems building in Denver to the Vandenberg Air Force Base in California in order to be integrated to the launch vehicle. The lander was launched on 5 May 2018 and arrived on Mars at approximately 19:54 UTC on 26 November 2018.
The spacecraft was launched on 5 May 2018 at 11:05 UTC on an Atlas V 401 launch vehicle (AV-078) from Vandenberg Air Force Base Space Launch Complex 3-East. This was the first American interplanetary mission to launch from California.
The launch was managed by NASA's Launch Services Program. "InSight" was originally scheduled for launch on 4 March 2016 on an Atlas V 401 (4 meter fairing/zero (0) solid rocket boosters/single (1) engine Centaur) from Vandenberg Air Force Base in California, U.S., but was called off in December 2015 due to a vacuum leak on the SEIS instrument. The rescheduled launch window ran from 5 May to 8 June 2018.
Major components of the launch vehicle include:
The journey to Mars took 6.5 months across for a touchdown on 26 November. After a successful landing, a three-month-long deployment phase commenced as part of its two-year (a little more than one Martian year) prime mission.
Cruise.
After its launch from Earth on 5 May in 2018, it coasted through interplanetary space for 6.5 months traveling across for a touchdown on 26 November in that year.
InSight cruise stage departed Earth at a speed of . The MarCo probes were ejected from the 2nd stage Centaur booster and traveled to Mars independent of the InSight cruise stage, but they were all launched together.
During the cruise to Mars, the InSight cruise stage made several course adjustments, and the first of these (TCM-1) took place on 22 May 2018. The cruise stage that carries the lander includes solar panels, antenna, star trackers, sun sensor, inertial measurement unit among its technologies. The thrusters are actually on the "InSight" lander itself, but there are cutouts in the shell so the relevant rockets can vent into space.
The final course correction was 25 November 2018, the day before its touch down. A few hours before making contact with the Martian atmosphere, the cruise stage was jettisoned, on 26 November 2018.
Entry, descent, and landing.
On 26 November 2018, at approximately 19:53 UTC, mission controllers received a signal via the Mars Cube One (MarCO) satellites that the spacecraft had successfully touched down at Elysium Planitia. After landing, the mission took three months to deploy and commission the geophysical science instruments. It then began its mission of observing Mars, which is planned to last for two years.
The spacecraft's mass that entered the atmosphere of Mars was . There were three major stages to InSight's landing:
Landing sequence:
The lander's mass is about but on Mars, which has 0.376 of Earth's gravity, it only weighs the equivalent of a object on Earth.
On 26 November 2018, InSight successfully touched down in Elysium Planitia.
A few hours after landing, NASA's "2001 Mars Odyssey" orbiter relayed signals indicating that "InSight" solar panels had successfully unfurled and are generating enough electrical power to recharge its batteries daily. "Odyssey" also relayed a pair of images showing "InSight" landing site. More images were acquired in stereo pairs to create 3D images, allowing "InSight" to find the best locations on the surface to place the heat probe and seismometer. Over the next few weeks, "InSight" checked health indicators and monitor both weather and temperature conditions at the landing site.
Landing site.
As "InSight" science goals are not related to any particular surface feature of Mars, potential landing sites were chosen on the basis of practicality. Candidate sites needed to be near the equator of Mars to provide sufficient sunlight for the solar panels year round, have a low elevation to allow for sufficient atmospheric braking during EDL, be flat and relatively rock-free to reduce the probability of complications during landing, and have soft enough terrain to allow the heat flow probe to penetrate well into the ground.
An optimal area that meets all these requirements is Elysium Planitia, so all 22 initial potential landing sites were located in this area. The only two other areas on the equator and at low elevation, Isidis Planitia and Valles Marineris, are too rocky. In addition, Valles Marineris has too steep a gradient to allow safe landing.
In September 2013, the initial 22 potential landing sites were narrowed down to four, and the "Mars Reconnaissance Orbiter" was then used to gain more information on each of the four potential sites before a final decision was made. Each site consists of a landing ellipse that measures about .
In March 2017, scientists from the Jet Propulsion Laboratory announced that the landing site had been selected. It is located in western Elysium Planitia at . The landing site is about north from where the "Curiosity" rover is operating in Gale Crater.
On 26 November 2018, the spacecraft successfully touched down at its landing site, and in early December 2018 "InSight" lander and EDL components were imaged from space on the surface of Mars. The images provided precise position of the lander: .
Surface operations.
On 26 November 2018, NASA reported that the "InSight" lander had landed successfully on Mars. The meteorological suite (TWINS) and magnetometer were operational, and the mission took approximately three months to deploy and commission the geophysical science instruments. After landing, the dust was allowed to settle for a few hours, during which time the solar array motors were warmed up and then the solar panels were unfurled. The lander then reported its systems' status, acquired some images, and it powered down to sleep mode for its first night on Mars. On its first sol on Mars it set a new solar power record of 4.6 kilowatt-hours generated for a single Martian day (known as a "sol"). This amount is enough to support operations and deploy the sensors.
On 7 December 2018, "InSight" recorded the sounds of Martian winds with SEIS, which is able to record vibrations within human hearing range, although rather low (aka subwoofer-type sounds), and these were sent back to Earth. This was the first time the sound of Mars wind was heard after two previous attempts.
On 19 December 2018, the SEIS instrument was deployed onto the surface of Mars next to the lander by its robotic arm, and it was commissioned on 4 February 2019. After the seismometer became fully operational, the heat probe instrument was deployed on 12 February 2019.
On 28 February 2019, the Heat Flow and Physical Properties Package probe (HP³) started digging into the surface of Mars. The probe and its digging mole were intended to reach a maximum depth of but it only went about , or three-quarters of the way out of its housing structure. After many attempts, the effort was given up as a failure in January 2021.
In April 2019, NASA reported that the Mars "InSight" lander detected its first marsquake.
In September 2019, researchers reported that "InSight" uncovered unexplained magnetic pulses, and magnetic oscillations.
In October 2019, the researchers at JPL concluded that the soil on Mars does not provide necessary friction for drilling, causing the mole to bounce around and form a wide pit around itself rather than dig deeper. They attempted a maneuver called in which they pressed the side of the scoop against the mole location to pin the side of the wall of the hole and increase friction. Pinning was initially successful, but then the mole backed out of its hole after a few weeks, suggesting the soil is accumulating below the mole.
On 24 February 2020, a summary of studies over the past year from InSight was presented which indicated that the planet Mars has active quakes, dust devils and magnetic pulses.
In February 2020, according to new data gathered from NASA's InSight lander, it was found that the Martian magnetic field at the landing site is about 10 times stronger than previously thought, and fluctuates rapidly.
In February 2020, the team reevaluated the risks of pushing the scoop directly against the back cap of the mole, and determined the procedure to be acceptable.
In June 2020, the team reported that the mole was finally underground, and was being evaluated to determine if the mole was able to dig as designed. On 9 July 2020, it was revealed that images taken on 20 June 2020 showed the mole bouncing again, indicating that it did not have sufficient friction to dig deeper. One suggested solution was to partially fill the hole with soil to increase friction.
By August 2020, the operations team had made some progress using the scoop to assist the mole in digging deeper into its hole, by pressing against the back. The scoop was used to fill the hole of the partially submerged mole, burying it fully for the first time. The team hoped the mole can now dig further into the surface on its own, possibly with the additional assistance of the scoop.
On 14 January 2021, the heat probe part of the mission was declared to be over, after the science team had determined that the soil properties at the landing location were too different from what the instrument had been designed for. The team attempted many different remedies over nearly two years to get the mole burrowing, but in the end, the attempts did not succeed. The friction between the soil and the probe was not enough for the mole to hammer itself deeper. Final attempts to get the probe deeper took place on 9 January 2021; after they proved unsuccessful, the decision was made to leave the probe as is and end attempts to dig deeper. The mole did (with all the assisting measures) burrow itself completely underground; the top of the mole is 2 to 3 centimetres below the Martian surface (with the mole itself being about 40 centimetres in length, the depth was thus about 43 centimetres). To be able to produce useful scientific measurement, the mole should have dug itself at least 3 metres deep. Although unsuccessful, the mole's operations did teach the mission team a lot about the soil at the InSight site, about conducting excavation/drilling on Mars, and about operating the lander's robotic arm (through the mole-rescue effort that used the arm in ways that were unplanned before the mission). Although the heat probe instrument (HP³) operations were ended, the seismometer (SEIS), radio experiment (RISE) and the weather instruments (TWINS) continue to operate as the lander's Mars surface mission was extended by two years, until end of December 2022.
In early 2021, the InSight team announced they would attempt to detect the arrival of the Mars 2020 mission using InSight's seismometers. Pre-landing modelling of the signals from Mars 2020's entry, descent and landing sequence suggested that the most probable source of any potential signal would be the impact of the spacecraft's cruise mass balance devices with the Martian surface, at speeds of around 4000 m/s.
On 12 April 2021, it was reported that Insight went into emergency hibernation because its Solar panels were filled with Martian dust.
On 14 April, the lander began to transmit images after waking from hibernation.
MarCO spacecraft.
The Mars Cube One (MarCO) spacecraft are a pair of 6U CubeSats that piggybacked with the "InSight" mission to test CubeSat navigation and endurance in deep space, and to help relay real-time communications (with an eight-minute lightspeed delay) during the probe's entry, descent and landing (EDL) phase. The two 6U CubeSats, named MarCO A and B, are identical. They were launched along with "InSight", but separated soon after reaching space, and they flew as a pair for redundancy while flanking the lander. They did not enter orbit, but flew past Mars during the EDL phase of the mission and relayed "InSight" telemetry in real time. The success of the MarCO spacecraft proved the viability of the cubesat platform for deep space missions and helped serve as a technical demonstration for potential future missions of a similar nature. On 5 February 2019, NASA reported that the CubeSats went silent, and are unlikely to be heard from again.
Team and participation.
The "InSight" science and engineering team includes scientists and engineers from many disciplines, countries and organizations. The science team assigned to "InSight" includes scientists from institutions in the U.S., France, Germany, Austria, Belgium, Canada, Japan, Switzerland, Spain, Poland and the United Kingdom.
Mars Exploration Rover project scientist W. Bruce Banerdt is the principal investigator for the "InSight" mission and the lead scientist for the SEIS instrument. Suzanne Smrekar, whose research focuses on the thermal evolution of planets and who has done extensive testing and development on instruments designed to measure the thermal properties and heat flow on other planets, is the lead for "InSight" HP3 instrument. The Principal Investigator for RISE is William Folkner at JPL. The SEIS Instrument
PI is Philippe Lognonné of IPGP, and the HP3 Instrument PI is Tilman Spohn of the DLR Institute of Planetary Research. The "InSight" mission team also includes project manager Tom Hoffman and deputy project manager Henry Stone. 
Major contributing agencies and institutions are:
Name chips.
As part of its public outreach, NASA organized a program where members of the public were able to have their names sent to Mars aboard "InSight". Due to its launch delay, two rounds of sign-ups were conducted totaling 2.4 million names: 826,923 names were registered in 2015 and a further 1.6 million names were added in 2017. An electron beam was used to etch letters only the width of a human hair (1 μm) onto silicon wafers. The first chip was installed on the lander in November 2015 and the second on 23 January 2018.