After launching on May 5, 2018, InSight began a 6.5-month cruise through space. On Nov. 26, it will hit a target point at the top of the Martian atmosphere at about six times the speed of a high-velocity bullet. It will then begin a process known as entry, descent and landing: It will decelerate enough in 6.5 minutes for a safe touchdown on Mars, deploying its three legs to absorb its impact on the Martian surface.

Over the course of a couple months, InSight will prepare for surface science operations by using a robotic arm to grasp its science instruments and place them directly onto the surface of Mars. It will be the first space mission to ever do so. Its heat probe will pound deeper into the Martian ground than any previous space mission has gone. InSight will continue to collect clues about the planet’s interior until at least November 2020.
More on MarCO

The Mars Cube One (MarCO) technology demonstration, which launched alongside InSight, has been flying separately to Mars.

Interplanetary Cruise and Approach to Mars

InSight’s interplanetary flight is called its cruise phase and takes a total of 205 days.

Key activities during cruise included checkouts and calibrations of spacecraft subsystems and science instruments, tracking of the spacecraft, attitude adjustments for changes in the pointing of the solar array and antennas, and maneuvers to adjust the spacecraft’s trajectory. InSight’s cruise was designed with six scheduled trajectory-correction maneuvers, plus two back-up or contingency opportunities.

Entry, Descent and Landing

InSight’s aeroshell, with the lander enclosed, will enter the top of the Martian atmosphere at about 12,300 mph (5.5 kilometers per second). In roughly 6.5 minutes, InSight will endure heat-generating atmospheric friction on its aeroshell, deploy a parachute and fire descent thrusters to decelerate to only about 5 mph (2.24 meters per second) before touching down on its shock-absorbing legs. This is the riskiest sequence in the entire mission. With dozens crucial steps required for success, it is often referred to as “the seven minutes of terror.” Those minutes and the preceding few hours of preparatory events are more formally called the mission’s entry, descent and landing (EDL) phase.


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.

The top of Mars’ atmosphere is actually a gradual transition to interplanetary space, not a sharp boundary. The atmospheric entry interface point -- the target point for the flight to Mars -- is set at 2,188.6 miles (3,522.2 kilometers) from the center of Mars. At this point, InSight is about 80 miles (128 kilometers) above the ground elevation of the planned landing site at Elysium Planitia, though the entry point is not directly above the landing site, but about 440 miles (708 kilometers) west of it.

At the interface point elevation, the entry target for the mission’s navigation team is a rectangle about 6 miles wide (10 kilometers) by 15 miles high (24 kilometers). In proportion to the distance of about 298 million miles (479 million kilometers) that InSight will fly from Earth to Mars, hitting a target that size is like scoring a soccer goal from about 80,000 miles (130,000 kilometers). Or like hitting a fast-moving target the size of a smart phone from the distance between New York and Denver.

Compared to the cross-section area of this target at the top of Mars’ atmosphere, the landing ellipse on the surface of Mars is larger -- about 81 miles (130 kilometers) generally west-to-east by about 17 miles (27 kilometers) north-to-south. The spacecraft has odds better than 99 percent of reaching the surface within this landing ellipse. Uncertainties that make the landing ellipse so much larger than the entry target include not only the precision of hitting the entry target but also aerodynamic factors, such as how much lift or drag the spacecraft will experience, and atmospheric variables, such as wind velocity and atmospheric density.

Preparing for Entry

At about 11 a.m. PST (2 p.m. EST) on Nov. 26, heaters will be turned on for catalyst beds of thrusters on the lander.

InSight will jettison its cruise stage seven minutes before entry. The remaining spacecraft after this separation is called the “entry vehicle” and consists of the aeroshell (back shell plus heat shield) and lander. Up to this point, radio transmission from InSight will have come via the medium-gain antenna on the cruise stage, but without it 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 70 seconds. Within the last two minutes 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. At the top of each of InSight’s legs is a trigger sensor; when the surface pushes up the leg and hits the trigger, it shuts off the lander’s retrorockets. It also sends out two signals that touchdown has been achieved: a “tone beacon” through its UHF antenna and a “beep” through its X-band antenna. This X-band “beep” is expected to turn on about seven minutes after landing, and will be a clear indicator that InSight is functional on the surface. On Earth, two radio telescopes will be listening for the tone beacon, which is 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 National Science Foundation’s Green Bank Observatory in Green Bank, West Virginia and the Max Planck Institute for Radio Astronomy’s facility at Effelsberg, Germany.

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 is completed.

Like Phoenix, But Different

The engineering for InSight’s EDL system draws significantly 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. InSight will enter the atmosphere at a lower velocity -- 12,300 mph (5.5 kilometers per second) compared to Phoenix, which entered at 12,500 mph (5.6 kilometers per second).

artists concept of Insight Lander

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

  • 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.

The following description of events from entry to touchdown is the latest estimate as of summer 2018.


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

Landing on Mars is an entirely automated process. But up until three hours before entering the Martian atmosphere, a team of engineers works to program the landing based on a variety of conditions. Daily weather updates from NASA’s Mars Reconnaissance Orbiter inform a team of EDL engineers who program InSight to complete each step of the landing process at a specific time. The times below are what the team expects as of October 2018. These times may shift depending on unexpected changes or environmental conditions.

The times also mark the moments when the spacecraft team expects to hear about a milestone, so they include the 8.1 minutes it takes to transmit a signal back from Mars. These times do not include the short, but increasing, delay in transmission that will come from the signals going into and out of the MarCO spacecraft on their way back to Earth.

At around 11:41 a.m. PST (2:41 p.m. EST), InSight will begin pivoting to put its heat shield face forward. Six minutes later, InSight will start sensing the top of the atmosphere. Before the parachute is deployed, friction between the atmosphere and the heat shield will remove nearly 99.5 percent of the entry vehicle’s kinetic energy. Peak heating will occur approximately 1.5 minutes after atmospheric entry, at around 11:49 a.m. PST (2:49 EST). The temperature at the external surface of the heat shield will reach about 2,700°F (about 1,500°C).

Peak deceleration will happen about 15 seconds later, at up to 7.5 g (greater than seven times the force of gravity at Earth’s surface). At this time, ionization of gas around the spacecraft from the intense heating may cause a temporary gap in the receipt of radio transmission from InSight.

InSight will continue to descend until the proper velocity and deceleration trigger conditions are met to deploy the parachute from the back shell. This is expected at approximately 11:51 a.m. PST (2:51 p.m. EST), at about 6.9 miles (11.1 kilometers) above ground level, at a velocity of about 861 mph (about 385 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 in 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 two minutes. During the first 25 seconds of parachute descent, InSight will jettison its heat shield and extend its three legs. About two minutes after the parachute opens and one minute before landing, the spacecraft will start using its radar to sense velocity and the distance to the ground.

Descent speed will have slowed to about 134 mph (60 meters per second) by the time the lander separates from the back shell and parachute, about two-thirds of a mile (1 kilometer) 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.

Illustration of InSight

Illustration of InSight descending toward Mars with its retrorockets firing.

Slowing for Touchdown

One 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 decelerate 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.

InSight is still traveling at 17 mph (7.7 meters per second) 164 feet (50 meters) above the ground when it transitions to constant velocity mode in preparation for soft touchdown. Approximately 15 seconds later, the vehicle will touchdown with a velocity of 5 mph (2.24 meters per second).

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 11:54 a.m. PST, or 2:54 p.m. EST). 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°F (minus 8°C) 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.

Uncertainties in EDL Timing

While this is the InSight team’s best estimate for landing times, the exact times may change before landing day. Additional trajectory correction maneuvers -- along with atmospheric conditions that change when certain EDL events happen -- could shift the timeline slightly.

Key Locations for Landing

Insight's team in Mission Control

InSight’s team in Mission Control preparing for landing at NASA’s Jet Propulsion Laboratory, Pasadena, California.

All of NASA’s Mars landings and many of its key deep space events are run from the Mission Support Area in JPL’s Mission Control. Since 1964, data has come to Mission Control from all of NASA’s deep space probes, earning it the nickname “Center of the Universe.” JPL’s Mission Control is the prime location during InSight’s entry, descent and landing.

After InSight lands, surface operations begin. This phase of the mission is directed from another building at JPL. Engineering decisions about the spacecraft, such as where to set down its instruments, will be made here.

InSight team

InSight team meeting in the Surface Operations Mission Support Area, JPL, Pasadena, California.

Lockheed Martin Space’s Waterton Campus in Littleton, Colorado, is where the InSight spacecraft was built and where the spacecraft operations team resides. The Lockheed Martin team is responsible for spacecraft health and safety during all mission phases. During the entry, descent and landing phase, its mission support area will supplement all missions operations and partner with the JPL mission operations support area.

Lockheed Martin Space, Waterton Campus, Littleton, Colorado

Lockheed Martin Space, Waterton Campus, Littleton, Colorado. Credit: Lockheed Martin Space

Illustration of InSight

InSight during surface operations, after the seismometer, heat flow probe and seismometer’s shield are deployed.

Mars Surface Operations

InSight’s surface operations phase will start one minute after touchdown. 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 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 (16 feet, or 5 meters) is expected to take about seven additional weeks. After that, the lander’s main job will be to sit still and continue collecting data from the instruments.

First Images

Once InSight has touched down on the Martian surface, there are several opportunities for the lander to send back an image from the Martian surface. The cameras will have their covers on for each of these opportunities, which could obscure the images slightly. (The first images from the Curiosity rover included its dust cover.)

image taken by an engineering model of NASA’s InSight lander

This image taken by an engineering model of NASA’s InSight lander in a Mars-like environment at NASA’s Jet Propulsion Laboratory, is expected to be similar to the first image InSight takes on Mars in aspect or geometry. The initial image will not be as sharp as this one, however, because the dust cover will still be on.

The lander has been programmed to take its first images several minutes after touchdown. The transmission of these images back to Earth will take longer. Engineering data are prioritized above images so it’s possible that only part of an image (or none at all) will be transmitted in the first hours after landing. The image could be transmitted at various times via MarCO, MRO or Odyssey.

rover image

How InSight’s First Images Could Be Returned to Earth:

  • MarCO, the experimental pair of CubeSats, could relay back a first image just after the entry, descent and landing phase. If this happens, the image (or partial image) could be available within 10 to 20 minutes of touchdown.
  • MRO could -- but is unlikely to -- relay back an image. MRO will prioritize relaying engineering data as it is setting over the Martian horizon. An image received via MRO wouldn’t be ready until late afternoon.
  • Odyssey could -- but is also unlikely to -- relay back images during its first pass, which occurs several hours after InSight lands. At that time, it will receive a recording of the EDL data from InSight. It may not be able to transmit image data before it passes over the horizon; if it did, it would be available in the early evening.
  • Odyssey will also pass over InSight the day after landing between 6 and 8 a.m. PST (9 and 11 a.m. EST) on Nov. 27.

First Weeks

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 workspace 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 the shield in place, the mission will begin monitoring Mars for seismic activity.

Insight Lander

An engineering version of the robotic arm on NASA’s InSight mission lifts the engineering version of the Heat Flow and Physical Properties Probe (HP³) at NASA’s Jet Propulsion Laboratory.

Deployments will continue with the 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 will then measure thermal conductivity before proceeding deeper.

Phoning Home

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 in 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 on most Martian mornings during this period. This would provide more planning time each day compared to the time available if commands were relayed via orbiter. Once the deployments using the arm have been completed, planning activity will become simpler and commanding can become less frequent.