InSight will launch in May or June 2018 from Central California. If skies are clear, the pre-dawn launch will likely be visible from much of coastal Southern California, including the Los Angeles and San Diego metropolitan areas.

The InSight spacecraft will fly for about six months to hit a target point at the top of the Martian atmosphere at about six times the speed of a high-velocity bullet; decelerate enough in seven minutes for a safe touchdown on Mars by a three-legged lander; use a robotic arm for the first time to grasp science instruments and then place them directly onto the surface of Mars over the course of a few weeks; pound a probe deeper into the Martian ground than ever before; then collect clues about the planet's interior until November 2020.

The Mars Cube One (MarCO) technology demonstration will share InSight's launch and fly separately to Mars.

Key activities of the InSight mission are launch, cruise, arrival (also known as entry, descent and landing) and Mars surface operations.

Illustration of InSight

Atlas V 401 launch vehicle, expanded view.

Launch Vehicle

A two-stage Atlas V 401 launch vehicle will lift the InSight spacecraft from Space Launch Complex 3 of Vandenberg Air Force Base, on Central California's Pacific coast.

The vehicle and launch services are provided by United Launch Alliance, Centennial, Colorado, a joint venture of Boeing Co. and Lockheed Martin Corp. The three numbers in the 401 designation signify a payload fairing -- or nose cone -- that is about 13 feet (4 meters) in diameter; zero solid-rocket boosters supplementing the main booster, and one engine on the upper stage. NASA selected an Atlas V 401 as InSight's launch vehicle in December 2013.

This launch vehicle's first stage is the common core booster with its fuel and liquid-oxygen tanks. This main booster is 107 feet (32.5 meters) long, with a diameter of 12.5 feet (3.8 meters). It has a throttleable RD-180 engine from a joint venture of United Technologies Corporation's Pratt & Whitney Division, East Hartford, Connecticut, and NPO Energomash, Moscow. Thermally stable kerosene fuel (type RP-1) and liquid oxygen will be loaded shortly before launch into cylindrical fuel tanks that make up about half of the total height of the vehicle. The common core booster can provide thrust of up to about 850,000 pounds (3.8 million newtons) at full throttle, controlled by an avionics system that provides guidance and sequencing functions.

Two interstage adapters connect the first stage of the Atlas with its Centaur upper stage. The Centaur is 41.7 feet (12.7 meters) long and 10.2 feet (3.1 meters) in diameter, with a restartable RL-10C engine from Aerojet Rocketdyne, Sacramento, California. This engine uses liquid hydrogen and liquid oxygen and can provide up to about 22,890 pounds (101,820 newtons) of thrust. The Centaur can control its orientation precisely, which is important for managing the direction of thrust while its engine is firing. It carries its own flight control computer and can release its payload with the desired attitude and spin rate.

The Centaur's aft bulkhead carrier holds the CubeSat deployment system that will contain the MarCO-A and MarCO-B CubeSats during the launch and release them after leaving Earth orbit. The interstage adapter attached to the Centaur encloses the aft bulkhead carrier while the stages are linked. At the other end of the upper stage, the Centaur's forward adapter provides structural and electronic interfaces with the InSight spacecraft.

The InSight spacecraft will ride into the pre-dawn sky inside a protective payload fairing atop the Centaur stage. The fairing is 40 feet (12.2 meters) long, with a diameter of 13.8 feet (4.2 meters) at the widest part, tapering to the top of the cone. It will be jettisoned shortly after ignition of the Centaur's engine, when the vehicle has climbed high enough to have escaped most of Earth's atmosphere.

With the payload fairing on top, the Atlas V 401 ready for launch will stand approximately 188 feet (57.3 meters) tall.


Previous Atlas Launches

The first Atlas V was launched in August 2002. InSight's launch is scheduled to be the 62nd Atlas V launch. An Atlas V 401 sent NASA's Mars Reconnaissance Orbiter on its way to Mars on Aug. 12, 2005; an Atlas V 541 launched NASA's Mars Science Laboratory spacecraft, including the Curiosity rover, on Nov. 26, 2011; and an Atlas V 401 launched NASA's Mars Atmosphere and Volatile Evolution (MAVEN) orbiter on Nov. 18, 2013. Other NASA deep space missions with Atlas V launches have included New Horizons (to Pluto) in 2006, Juno (to Jupiter) in 2011, and Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer (OSIRIS-REx asteroid sample-return mission) in 2016.

Launch Scheduling and Location

As Earth and Mars race around the Sun, with Earth on the inside track, Earth laps Mars about once every 26 months. Launch opportunities to Mars occur at the same frequency, when the planets are positioned so that a spacecraft launched from Earth will move outward and intersect Mars in its orbit several months later. This planetary clockwork, plus the launch vehicle's power, the spacecraft's mass, and the desired geometry and timing for the landing on Mars are all factors in determining the range of possible launch dates.

InSight's launch period is May 5 through June 8, 2018, with multiple launch opportunities over windows of approximately two hours each date. Launch opportunities are set five minutes apart during each date's window. The first launch opportunity will begin at 4:05 a.m. PDT (7:05 a.m. EDT / 11:05 UTC) on May 5.

Whichever date the launch occurs, InSight's landing on Mars is planned for Nov. 26, 2018, around noon PST (3 p.m. EST / 20:00 UTC).

Vandenberg Air Force Base is near Lompoc, California, about one-third of the way from Los Angeles to San Francisco on the Pacific Coast. The base is headquarters of the 30th Space Wing, U.S. Air Force Space Command.

InSight is the first interplanetary launch from the West Coast. Most launches from Vandenberg put Earth satellites into near-polar orbits. Examples include NASA Earth science missions Soil Moisture Active Passive, launched in 2015, and Orbiting Carbon Observatory 2, launched in 2014. The most recent Atlas V liftoff from Vandenberg was the Sept. 24, 2017, launch of a National Reconnaissance Office spacecraft. For safety, launches are directed seaward.

All previous NASA interplanetary missions have launched from Florida's Atlantic coast, at either Cape Canaveral Air Force Station or the adjacent NASA Kennedy Space Center. Launching toward the east adds the momentum of Earth's eastward rotation to the launch vehicle's own thrust. For InSight, the Atlas V 401 offers enough performance to enable launching a Mars mission southward from Vandenberg, mitigating a more-crowded launch schedule in Florida.


Visibility

If the weather is clear, the InSight launch could be visible from as far north as Bakersfield, California, to perhaps as far south as Rosarito, Mexico.

Launch Sequences

The launch time, called "T Zero," is when the engine is ready and 1.1 seconds before liftoff. Ignition of the Atlas V-401 first-stage common core booster is at 2.7 seconds before T Zero, or 3.8 seconds before liftoff.

After a short vertical rise away from the pad, the launch vehicle will begin a maneuver to travel in its prescribed direction (southward). The common core booster engine of the first stage will continue to burn until about 244 seconds after T Zero, ending with "booster engine cutoff," or BECO.

About six seconds after booster engine cutoff, the first stage will be jettisoned from the Centaur upper stage. It will fall into the Pacific Ocean. At the separation of the two stages, the interstage adapters will also fall away, exposing the Centaur's aft bulkhead carrier where the twin MarCO spacecraft ride inside their CubeSat dispensers. Approximately 10 seconds after separation of the two stages, the Centaur engine will begin the first of its two burns. The launch vehicle will jettison the payload fairing eight seconds later, uncovering InSight. The first burn of the Centaur's engine, lasting about nine minutes, will insert the combined upper stage and spacecraft into a parking orbit. The end of this burn is called "main engine cutoff one," or MECO1, at about 13 minutes after lift-off.

The shape of the parking orbit is nearly circular at an altitude of 115 miles (185 kilometers). However, the spacecraft will not complete even one orbit. After the Centaur main engine's first burn, the Centaur-spacecraft stack will coast in the parking orbit until it reaches the proper position for start of the second Centaur burn. This coasting will last 59 to 66 minutes, depending on the date and time of the launch. About when the Centaur-spacecraft stack begins passing over Antarctica, it will exit Earth's shadow and enter sunshine. The Centaur will maintains a slow roll while in the parking orbit -- about 1.5 degrees per second -- to balance the thermal load of exposure to direct sunlight.



Illustration of InSight Launch Sequences

Profile of InSight launch events, for launch at first opportunity on May 5, 2018, from Space Launch Complex 3E at Vandenberg Air Force Base in California. The "T Zero" time is 1.1 seconds before liftoff. Times of other launch events are given in number of seconds after T Zero. Download image

The second Centaur burn, continuing for about five minutes as the stack passes close to the North Pole, will loft the spacecraft out of Earth orbit and on its way toward Mars. The burn ends with "main engine cutoff two," (MECO2). Nine minutes after that cutoff, actuators and push-off springs on the second stage of the Atlas will release the InSight spacecraft with a separation velocity sufficient to avoid re-contact with the upper stage. Spacecraft separation will occur about 90 minutes after liftoff for the first May 5 launch opportunity as the spacecraft is approximately over the Alaska-Yukon region.

Shortly after the release of InSight, the Centaur will begin an avoidance maneuver taking itself out of the spacecraft's flight path to avoid hitting either the spacecraft or Mars. Shortly after InSight separation, MarCO-A will be released by its CubeSat dispenser, the Centaur will roll 180 degrees, MarCO-B will be released, and then the Centaur will complete its avoidance maneuver.

Throughout the launch sequence, radio transmissions from the Atlas to NASA's Tracking and Data Relay Satellite System will enable ground controllers to monitor critical events and the status of the launch vehicle and the spacecraft. Neither InSight nor MarCO can begin their own transmissions until after they have been released. The solar array on the cruise stage of the InSight spacecraft was built to fit fully extended inside the fairing, with no need for deployment action after the spacecraft's release. Separation from the launch vehicle triggers InSight to acquire information about its orientation from its attitude control system and then slew to correct its attitude for communication.

Acquisition of Signal

The radio signal transmitted by InSight could be first detected at any time from momentarily after spacecraft separation to about 14 minutes after spacecraft separation. This puts expected "acquisition of signal," or AOS, no later than about 107 minutes after launch (around 6 a.m. PDT, if the launch is at the first opportunity at 4:05 a.m. PDT on May 5). The initial acquisition is expected to be by an antenna at the Goldstone, California, station of NASA's Deep Space Network (DSN), followed by the DSN station at Canberra, Australia.

MarCO-A and MarCO-B, after their release from the Centaur, will deploy solar arrays and then execute a "detumble" maneuver to stabilize attitude and point their solar arrays at the sun. Because the MarCOs’ batteries were last charged several months before launch, the priority after pointing their solar arrays is recharging their batteries to enable a full communications session. That session is expected to happen with the Canberra DSN station approximately seven hours after separation for MarCO-A (about 12:30 p.m. PDT or 3:30 p.m. EDT if the launch occurs the first launch opportunity) and 8 ½ hours after separation for MarCO-B (about 2 p.m. PDT or 5 p.m. EDT if the launch occurs at the first launch opportunity).

If the battery charge level is high and all other activities have gone as planned, the MarCOs could each attempt a short five-minute burst of data transmission after solar array deployment and before going out of sight of the Goldstone DSN station. This could happen within about an hour and a half after separation -- or about three hours after launch. (If launch occurs at the first opportunity, the bursts could occur by around 7 a.m. PDT [10 a.m. EDT]). However, these bursts will only happen if the team is lucky and the antennas on both spacecraft and the ground are able to point towards each other so soon after separation.The five-minute burst may give a hint of how the MarCOs are doing.

Data received from InSight in the minutes after the initial acquisition will enable an evaluation of the spacecraft's health. The flight team will be looking for confirmations that the cruise-stage solar arrays are producing electricity and that temperatures measured at many locations on InSight are within expectations. Once the spacecraft is confirmed to be in good health with stable temperatures and power, transition to cruise phase activities can begin on the day after launch.

Interplanetary Cruise and Approach to Mars

If launch is at the start of the launch period, May 5, the trip to Mars will take 205 days. If launch is at the end of the launch period, June 8, the trip will take 171 days. The use of a constant arrival date -- Nov. 26, 2018 -- for any launch date helped simplify operations planning. This interplanetary flight is called InSight's cruise phase, with the final 60 days before arrival at Mars designated the approach subphase of cruise. The cruise phase will end three hours before InSight enters the Martian atmosphere.

Key activities during cruise will include checkouts and calibrations of spacecraft subsystems and science instruments, tracking of the spacecraft, attitude adjustments for changes in pointing of the solar array and antennas, and maneuvers to adjust the spacecraft's trajectory. Six trajectory correction maneuvers are scheduled, plus two back-up or contingency opportunities for maneuvers.

InSight's mission design uses what is called a Type 1 trajectory to Mars, meaning the spacecraft will fly less than halfway around the Sun while in transit from one planet to the other.

During cruise, the InSight lander will remain tucked inside its aeroshell, with the aeroshell attached to the cruise stage. The InSight spacecraft is not designed to use spin for stability during cruise, as some previous Mars spacecraft have. It will maintain three-axis stability by monitoring its attitude and firing thrusters intermittently to keep within prescribed bands of orientation for each axis. For monitoring its attitude, the InSight spacecraft will use a star tracker and a gyroscope-containing inertial measurement unit, backed up by Sun sensors.

Eight thrusters in all will be used during cruise. They are mounted on the lander and extend through cutouts in the back shell. The larger four -- called trajectory correction maneuver thrusters -- will be used for maneuvers to adjust the spacecraft's flight path, with the smaller four -- called reaction control system thrusters -- controlling roll of the spacecraft during those maneuvers and providing attitude control throughout cruise.

Schematic view of InSight cruise phase from Earth to Mars

Schematic view of InSight cruise phase from Earth to Mars, for May 5, 2018, launch. Possible launch dates are May 5 through June 8. The date of arrival and atmospheric entry at Mars will be Nov. 26, 2018. Six trajectory maneuvers (TCMs) are scheduled. Dates are given relative to launch or entry.
Download image

Shaping the Trajectory to Mars

InSight's first trajectory correction maneuver is scheduled for 10 days after launch. The second is scheduled for July 28, 2018, (121 days before landing). These two will be used to remove the launch-day trajectory's intentional offset from Mars. That intentional offset is built into launch planning as a planetary protection precaution to avoid the possibility of the launch vehicle's upper stage reaching Mars without having been cleaned to the standards of a Mars-landing spacecraft. The spacecraft will spend the first 10 days of cruise on a trajectory that would miss Mars by hundreds of thousands of miles or kilometers.

Additional trajectory correction maneuvers are scheduled for Oct. 12, Nov. 11, Nov. 18, and Nov. 25 (45 days, 15 days, eight days and 22 hours before landing). The purpose of these is to refine the flight path for hitting the targeted entry point at the top of the Martian atmosphere on landing day. Nov. 21 will be a back-up opportunity if a Nov. 18 maneuver is not performed as planned. A contingency opportunity is on the schedule for eight hours before landing, if needed.

Tracking During Cruise

Planning for each trajectory correction maneuver will combine assessments of the spacecraft's trajectory with calculations of how to use the thrusters on the cruise stage to alter the trajectory. Navigators' assessments of the spacecraft's trajectory use three types of tracking information from deep-space antennas at multiple locations on Earth. One method is ranging, which measures the distance to the spacecraft by timing precisely how long it takes for a radio signal to travel to the spacecraft and back. Another is Doppler, which measures the spacecraft's speed relative to Earth by the amount of shift in the pitch of a radio signal from the craft. The third method, called delta differential one-way range measurement, adds information about the location of the spacecraft in directions perpendicular to the line of sight. For this method, pairs of antennas on different continents simultaneously receive signals from the spacecraft, and then the same antennas observe natural radio waves from a known celestial reference point, such as a quasar, which serves as a navigation reference point.

For communication and navigational tracking during cruise, InSight will use NASA's Deep Space Network antenna stations at Goldstone, California; near Madrid, Spain, and near Canberra, Australia, augmented with support being provided by the European Space Agency's Deep Space Antenna 3 at Malargüe, Argentina, and Deep Space Antenna 1 at New Norcia, Australia.

The final 15 days of the approach phase include activities in preparation for the spacecraft's arrival at Mars, or its atmospheric entry, descent and landing. The schedule during this period includes six opportunities to update parameters for the onboard software that will autonomously control events during the entry, descent and landing.

Entry, Descent and Landing

If launch is at the start of the launch period, May 5, the trip to Mars will take 205 days. If launch is at the end of the launch period, June 8, the trip will take 171 days. The use of a constant arrival date -- Nov. 26, 2018 -- for any launch date helped simplify operations planning. This interplanetary flight is called InSight's cruise phase, with the final 60 days before arrival at Mars designated the approach subphase of cruise. The cruise phase will end three hours before InSight enters the Martian atmosphere.

illustration

Navigators' target at the top of Mars' atmosphere is smaller than the ellipse covering the area in which the spacecraft has a 99 percent chance of touching down after passing through that target. Dispersion factors include aerodynamic uncertainties and atmospheric variability. This concept illustration is not to scale. Download image

Key activities during cruise will include checkouts and calibrations of spacecraft subsystems and science instruments, tracking of the spacecraft, attitude adjustments for changes in pointing of the solar array and antennas, and maneuvers to adjust the spacecraft's trajectory. Six trajectory correction maneuvers are scheduled, plus two back-up or contingency opportunities for maneuvers.

InSight's mission design uses what is called a Type 1 trajectory to Mars, meaning the spacecraft will fly less than halfway around the Sun while in transit from one planet to the other.

During cruise, the InSight lander will remain tucked inside its aeroshell, with the aeroshell attached to the cruise stage. The InSight spacecraft is not designed to use spin for stability during cruise, as some previous Mars spacecraft have. It will maintain three-axis stability by monitoring its attitude and firing thrusters intermittently to keep within prescribed bands of orientation for each axis. For monitoring its attitude, the InSight spacecraft will use a star tracker and a gyroscope-containing inertial measurement unit, backed up by Sun sensors.

Eight thrusters in all will be used during cruise. They are mounted on the lander and extend through cutouts in the back shell. The larger four -- called trajectory correction maneuver thrusters -- will be used for maneuvers to adjust the spacecraft's flight path, with the smaller four -- called reaction control system thrusters -- controlling roll of the spacecraft during those maneuvers and providing attitude control throughout cruise.

Preparing for Entry

About 47 minutes before entry, heaters will be turned on for catalyst beds of thrusters on the lander.

Up through this point during approach to Mars, radio transmission from InSight will come via the medium gain antenna on the cruise stage. Seven minutes before entry, the spacecraft will jettison the cruise stage. The remaining spacecraft after this separation is called the "entry vehicle" and consists of the aeroshell (back shell plus heat shield) and lander. Moments after the separation, InSight will begin transmitting a carrier-only (no data) signal from an omni-directional antenna on the back shell, called the wrap-around patch antenna.

About 30 seconds after cruise stage separation, the entry vehicle will begin turning toward the orientation required for atmospheric entry, with the heat shield facing forward. The turn will take about 90 seconds. Shortly before entry, the wrap-around patch antenna will begin transmitting data at eight kilobits per second, in the ultrahigh frequency (UHF) radio band.

Listening for InSight

NASA's Mars Reconnaissance Orbiter (MRO) is expected to be in position to receive the transmissions during InSight’s entry, descent and landing. MRO, passing over InSight's landing region on Mars, will record the data for transmitting to Earth during a later orbit.

After carrying out a number of risky communication and navigation flight experiments, the twin MarCO spacecraft may be in position to receive transmissions during InSight’s entry, descent and landing as well. If all goes well, the MarCOs may be able to relay data to Earth almost immediately.

On Earth, three radio telescopes will be listening for a very basic indicator of InSight’s status: They may be able to confirm that InSight is transmitting during descent and after landing. They are the Max Planck Institute for Radio Astronomy's facility at Effelsberg, Germany; the Institute of Radio Astronomy of Bologna’s Sardinia Radio Telescope, on the Italian island of Sardinia, and the National Science Foundation's Green Bank Observatory in Green Bank, West Virginia.

NASA’s Mars Odyssey orbiter is expected to provide information about InSight after the landing because it is scheduled to fly over InSight after the entry, descent and landing process.

Like Phoenix, But Faster

The engineering for InSight's entry, descent and landing system draws heavily on the technology of NASA's Phoenix Mars Lander. The system that performed successfully for the Phoenix landing in 2008 weighs less than the landing systems with airbag or "sky crane" features used by NASA's Mars rover missions. The lean hardware helps give InSight, like Phoenix, a high ratio of science-instrument payload to total launch mass, compared with rovers.

Compared with Phoenix, though, InSight's landing presents four significant challenges:


  • InSight will enter the atmosphere at higher velocity -- 13,200 miles per hour (5.9 kilometers per second) vs. 12,500 miles per hour (5.6 kilometers per second).
  • InSight will have more mass entering the atmosphere -- about 1,340 pounds (608 kilograms) vs. 1,263 pounds (573 kilograms).
  • InSight will land at an elevation about 4,900 feet (1.5 kilometers) higher than Phoenix did, so it will have less atmosphere to use for deceleration.
  • InSight will land during a Martian season (early winter in the northern hemisphere) when dust storms have grown to global proportions in some prior Martian years.

Some changes in InSight's entry, descent and landing system, compared to the one used by Phoenix, are:


  • InSight will use a thicker heat shield, to handle the possibility of being sandblasted by a dust storm.
  • InSight's parachute will open at higher speed.
  • InSight will use stronger material in parachute suspension lines.

Times given in the following description of events from entry to touchdown may be changed before November 2018. This description, from planning before launch, is an example of a possible timeline. Some of the timeline will be an estimate until after the landing because certain key events, such as parachute deployment, can be responsive to atmospheric conditions during descent, rather than clock-driven.

illustration

Profile of InSight entry, descent and landing events on Nov. 26, 2018, for one typical case. Exact timing will be affected by atmospheric conditions on landing day. Download image

Into the Atmosphere

Five minutes after completing the pivot to put its heat shield facing forward, InSight will start sensing the top of the atmosphere. Friction between the atmosphere and the heat shield during roughly 3.5 minutes before parachute deployment will take about nine-tenths of the velocity out of descent. Peak heating will occur approximately 1.5 minutes after atmospheric entry. The temperature at the external surface of the heat shield will reach about 2,700 degrees Fahrenheit (about 1,500 degrees Celsius). Deceleration will peak about 17 seconds later, at up to 7.4 g (about seven times the equivalent of acceleration due to gravity at Earth's surface). Ionization of gas around the spacecraft from the intense heating may cause a temporary gap in receipt of radio transmission from InSight.

Deployment of InSight's parachute from the top of the back shell may be triggered by either velocity or deceleration level and is expected at approximately 3.5 minutes after entry, at about 7.5 miles (12 kilometers) above ground level, at a velocity of about 930 miles per hour (about 415 meters/sec). The anticipated load on the parachute when it first opens is about 12,500 pounds of force (55,600 newtons). Approximately 10 seconds after parachute deployment, electronics of the spacecraft's landing radar will be powered on to warm up, and an auxiliary battery will be activated to supplement the lander's main battery during critical current-drawing events of the next few minutes.

Parachute testing

Parachute testing for InSight, conducted inside world's largest wind tunnel, at NASA Ames Research Center, Moffett Field, California. Download image

The spacecraft will descend on the parachute for about three minutes. During the first 25 seconds of that period, InSight will jettison its heat shield and extend its three legs. About 75 seconds after the parachute opens and 130 seconds before landing, the spacecraft will start using its radar to sense the distance to the ground.

Descent speed will have slowed to about 134 miles per hour (60 meters per second) by the time the lander separates from the back shell and parachute, about three-fourths of a mile (1.2 kilometers) above the ground and about 45 seconds before touchdown. By design, the separation is triggered by radar sensing of altitude and velocity. A brief pause in communication is anticipated as data transmission shifts from the wrap-around antenna on the back shell to a helical UHF transmitter on the lander.



Slowing for Touchdown

Half a second after lander separation, the 12 descent engines on the lander will begin firing. Guidance software onboard for the terminal descent will provide commands for aligning the direction of thrust to the direction the spacecraft is moving, so the thrust will counter horizontal movement as well as decelerating the descent. If the spacecraft senses that its horizontal speed is below a threshold set in the software, it will also perform a maneuver to avoid the back shell that is still descending on its parachute. This maneuver would adjust the direction of thrust to reduce the chance that the back shell and parachute could land too close to the lander after the lander's touchdown. The spacecraft will rotate to land in the desired orientation: with solar arrays extending east and west from the deck and the robotic arm's work area on the south side of the lander.

At about 164 feet (50 meters) above the ground InSight will begin a transition to a constant descent velocity of 5.4 miles per hour (2.4 meters per second), the velocity at which it will touch down less than half a minute later.

The local solar time at the landing site in the Elysium Planitia area of Mars will be about 2 p.m. at touchdown (which will be about 12 noon in California). If it is a relatively clear day -- no dust storm -- the forecast calls for air temperature at the height of the lander deck to reach about 18 degrees above zero Fahrenheit (minus 8 Celsius) that afternoon and plummet to about minus 140 F (minus 96 C) overnight. The time of year in Mars' northern hemisphere will be about midway between the autumn equinox and winter solstice.

The Martian day, or sol, of the landing will count as Sol Zero of InSight's Mars surface operations.

Mars Surface Operations

InSight's surface operations phase will start one minute after touchdown. The prime mission will operate on the surface for one Martian year plus 40 Martian days, or sols, until Nov. 24, 2020. Some science data will be collected beginning the first week after landing, but the mission’s main focus during that time is preparing to set InSight’s instruments directly on the Martian ground.

Placement of instruments onto the ground is expected to take about 10 weeks. Sinking the heat probe to full depth is expected to take about seven weeks further. After that, the lander's main job will be to sit still and continue collecting data from the instruments.

InSight will rely on battery-stored energy as it descends through the atmosphere and until the lander's solar arrays can be opened after touchdown, so deploying the arrays is a crucial early activity. However, the lander will first wait about 16 minutes to let any dust from the landing settle, in order to avoid having the dust settle onto the arrays' photovoltaic cells. During those minutes, the motors for unfurling the arrays will begin warming in preparation. The two arrays will take a few minutes to fully deploy, beginning about 25 minutes after touchdown to allow sufficient warming of the motors.

Tasks on landing day will be programmed to be performed autonomously, without any need for the lander to receive communication from the InSight team on Earth. The landing-day activities other than deploying the solar arrays will include checking the lander's health indicators, taking a wide-angle image toward the south, and powering down to "sleep" mode for the first night on Mars.

First Weeks

In the first week, InSight will continue to characterize the landing site, the payload instruments, the robotic arm and other onboard systems, and begin stereo imaging of the ground within reach of the arm on the south side of the lander. During the next two weeks, InSight will return additional images of the arm's work space, for use by the InSight team in selecting the best locations to place the seismometer (SEIS) and heat probe (HP3) onto the ground. Stereo pairs of images will provide three-dimensional information.

The seismometer will be the first instrument lifted from the deck and placed on the ground. The transfer will require several sols to verify steps such as the robotic arm's good grasp on the instrument before proceeding to the next step, especially since this will be the first time a robotic arm has ever grasped anything on another planet. Next, the InSight team will use the robotic arm to place the wind and thermal shield over the seismometer. With that shield in place, the mission will begin monitoring Mars for seismic activity. Deployments will continue with placement of HP3 onto the ground. After it is in place, the instrument will release its self-hammering mole. As the mole burrows downward during the next few weeks, it will pause at intervals to allow heat from the hammering action to dissipate for two or three sols and it will then measure thermal conductivity before proceeding deeper.

Phoning Home

Throughout its surface operations, InSight will relay its science data to Earth via NASA's Mars Reconnaissance Orbiter and Mars Odyssey orbiter. The orbiters will receive UHF-band transmissions from InSight and subsequently forward the data to Earth via X-band transmissions to NASA's Deep Space Network antenna complexes at Goldstone in California's Mojave Desert, near Madrid, Spain, and near Canberra, Australia. At any point in Earth's daily rotation, at least one of these three sites will have Mars in view for radio communication. Each complex is equipped with one antenna 230 feet (70 meters) in diameter, at least two antennas 112 feet (34 meters) in diameter, and smaller antennas. All three complexes communicate directly with the Space Flight Operations Facility hub at NASA's Jet Propulsion Laboratory, Pasadena, California.

During the weeks until both the seismometer and heat probe have been placed onto the ground, the orbiter will provide relay opportunities an average of twice per sol. This will enable the InSight team, on most days, to use results from each sol's activities for planning the next sol's activities, including arm movements. The mission will use X-band transmission of daily commands directly from Earth to the lander most Martian mornings during this period, to provide more daily planning time compared to relaying commands via the orbiter. Once the deployments using the arm have been completed, planning activity will become simpler and commanding can become less frequent.

BACK TO TOP