NASA is targeting a launch no earlier than Oct. 12, 2023 for the Psyche spacecraft. It will launch from NASA’s Kennedy Space Center in Florida on a journey to the metal-rich asteroid of the same name. It is expected to fly by Mars in the spring of 2026 and use the Red Planet’s gravity to swing itself toward the outer part of the main asteroid belt, where the asteroid Psyche orbits. In August 2029, after a six-year journey of about 2.2 billion miles (3.6 billion kilometers), the spacecraft will start orbiting the asteroid for at least 26 months.
Psyche will lift off from Launch Pad 39A at Kennedy aboard a SpaceX Falcon Heavy rocket, procured by NASA’s Launch Services Program.
Psyche will launch with a NASA ride-along: the Deep Space Optical Communications (DSOC) technology demonstration, which is attached to the Psyche spacecraft but is an experiment separate from the Psyche mission.
Psyche’s launch period opens Oct. 5, with opportunities through Oct. 25. A Psyche launch on Oct. 12 would occur at 10:16 a.m. EDT (7:16 a.m. PDT). The launch window for each day is “instantaneous,” meaning that the mission would launch at an exact time or reset for the next day. For the length of the launch period, the expected launch times generally vary only up to about a half-hour.
The spacecraft’s journey to the asteroid Psyche requires meticulous planning. Because the spacecraft will rely on a flyby of Mars to slingshot it out toward the asteroid Psyche, the mission team must factor in the movement of Earth and Mars around the Sun. Earth and Mars align closely only about once every 26 months. Determining the range of possible launch dates depends on this planetary clockwork, plus several other factors: the rocket’s power, the Psyche spacecraft’s mass, the thrust of the spacecraft’s propulsion system, and the desired geometry and timing of the Mars flyby as well as the desired start of orbits around the asteroid. All dates in the launch period will allow for the gravity of the asteroid Psyche to capture the spacecraft around late July 2029 and for the mission to begin its science campaign in August 2029.
Psyche is the first in a series of scientific missions from NASA and its partners to be launched on a SpaceX Falcon Heavy rocket. Over the next three years, the Falcon Heavy will give a ride to NOAA’s GOES-U (a collaboration with NASA), as well as NASA’s Europa Clipper, and Nancy Grace Roman Space Telescope. Psyche is the second interplanetary mission SpaceX has launched on behalf of NASA.
The Falcon Heavy is a two-stage rocket with side boosters. After the side boosters separate and return to land, the main engine cuts off. The core stage is then expended into the Atlantic Ocean. At that point, the second stage of the rocket will fire its engine. The second stage helps Psyche escape the grip of Earth’s gravity.
Exact timelines will vary by launch date, but separation from the rocket is expected to occur a little over an hour after liftoff. If Psyche launches on Oct. 5, for instance, the spacecraft would separate from the rocket about an hour and three minutes after liftoff.
After separating from the Falcon Heavy rocket, Psyche will power up its miniature inertial measurement unit (MIMU) to sense if the spacecraft is rotating. The MIMU will help the spacecraft stop any rotation before the next key step: deploying the two cross-shaped solar arrays, each of which consists of five panels.
The spacecraft begins deploying the solar arrays within about six minutes after separation. Stowed flat against opposite sides of the spacecraft, the arrays will unfold one at a time. Each will take about two minutes to release hold-downs that keep them in their stowed position, and about six minutes to unfold and lock into their final position. The pair is expected to be fully deployed in about 21 minutes. Then the spacecraft will start searching for the Sun and reorient itself so that the solar arrays, which spin on a central axis, directly face the Sun.
Once the solar arrays are deployed, the spacecraft will also command itself into “safe mode.” In this mode, the spacecraft points one of its low-gain antennas at Earth for communications and completes only minimal engineering activities, awaiting further commands from mission controllers on Earth.
Psyche may be able to connect with these mission controllers and provide real-time data as early as about five minutes after spacecraft separation, before initiating the deployment of its solar arrays. But the best chance for catching Psyche’s signal on Earth will occur after deployment is complete, during the safe mode period when the spacecraft is rotating like a rotisserie. It could take up to two hours after separation from the rocket before the first signal is received.
Two of NASA’s Deep Space Network facilities will be tracking the Psyche spacecraft around the time of launch. The complex in Canberra, Australia, is expected to come into the spacecraft’s line of sight shortly before the spacecraft separates from the launch vehicle. The Goldstone complex near Barstow, California, is expected to come into the spacecraft’s view between 20 and 36 minutes after Psyche separates from the rocket. The Canberra complex is expected to pick up the signal first.
An initial checkout phase begins when mission controllers have confirmed that Psyche is drawing power from its solar arrays, operating at an appropriate temperature, and engaging in two-way communications with Earth. This phase should begin several hours after liftoff and end about 100 days after launch.
A key purpose of initial checkout is to make sure the flight and ground systems are ready for the spacecraft’s thrusters to begin continuously firing. Checkout of the propulsion system is expected to begin several days after launch and include intermittent short and long firings of all four thrusters, with mandatory checkouts completed around six weeks after launch. Another purpose of this phase is to verify the ground team’s ability to control, monitor, and operate the spacecraft every day.
Once those primary goals are met, the team will focus on a number of secondary goals, including making sure the flight systems are healthy in preparation for cruising to the asteroid and for calibrating the science instruments.
While most instrument activities occur after the propulsion checkout, three will take place during the early part of the checkout period. The magnetometer, which observes changes in the spacecraft’s magnetic field during its checkout activities, is expected to be activated in the first few days after launch. Heaters that help the gamma-ray spectrometer and the imager reach a steady state in the dry, cold conditions of space will also be turned on several weeks after launch.
Active checkout of all the science instruments starts about six weeks after launch. This is the period when the imager will take its first images for calibration purposes, targeting standard stars and a star cluster at a variety of exposures, with several different filters. After this initial checkout of the instrument, the Psyche team will start an automatic feed of raw images to the website go.nasa.gov/3sdfRIN for the duration of the mission.
The first opportunity to power on the Deep Space Optical Communications (DSOC) technology demonstration is expected to come about 20 days after launch, when Psyche remains fairly close to Earth (about 4.7 million miles, or 7.5 million kilometers, away). More information on the technology demonstration is available in the DSOC section.
Psyche’s cruise phase begins about 100 days after launch, when the spacecraft is ready to fire its thrusters nearly continuously. This phase lasts more than five years as the spacecraft journeys to the metal-rich asteroid. Along the way, there will be periodic flight software updates as well as maintenance and calibration activities for the science instruments and engineering systems. The DSOC experiment will also perform its valuable technology demonstration for future missions during this phase.
Cruise is divided into three parts: Cruise 1, Mars Gravity Assist, and Cruise 2.
Cruise 1 covers the trajectory from Earth to Mars and requires extended use of Psyche’s thrusters to get on track to meet up with Mars on time. If all goes as planned, Cruise 1 begins 100 days after launch and ends 60 days before the flyby of Mars in May 2026.
Psyche will be flying relatively close to Mars for what is called a gravity assist: Harnessing the planet’s gravity, Psyche will use the speed at which Mars travels around the Sun to increase the spacecraft’s own speed and change its direction without using much propellant. This effect is similar to how a ball thrown at a moving train will bounce off the train in another direction at a higher speed. If Psyche launches early in its launch period, the spacecraft will be traveling at about 45,600 mph (102,800 kph) relative to the Sun five days before the Mars flyby. Five days after the closest approach to Mars, Psyche will be traveling about 52,200 mph (104,900 kph) relative to the Sun.
During the Mars Gravity Assist period, Psyche will mostly turn off its thrusters and coast to Mars. Because the performance of each thruster can vary slightly, precision navigation to Mars will be easier with the thrusters off. Engineers will restart them for short periods to complete what are known as “Mars trim maneuvers” to bring the spacecraft closer to the Red Planet.
Psyche’s close approach to Mars will be in May 2026, although the exact date and the exact altitude above the planet vary slightly based on when Psyche launches. (Possible dates of closest approach throughout the launch period all fall in May 2026.) The spacecraft is expected to fly between about 1,900 to 2,700 miles (3,000 to 4,400 kilometers) above Mars – a safe distance above the planet yet close enough to get a gravity assist. Psyche will likely be traveling at about 13,000 mph (21,000 kph) relative to the surface of Mars.
Two days after the Mars gravity assist, the spacecraft will begin Cruise 2, an approximately 29-month journey requiring near-continuous use of its thrusters. Cruise 2 ends as the orbiter starts its approach to the asteroid Psyche in the spring of 2029.
As the spacecraft cruises to the asteroid, the Sun will block the spacecraft’s view of Earth for several days. During this period, known as solar conjunction, Psyche will not be able to communicate reliably with mission controllers, but the spacecraft is programmed to get closer to the asteroid without having to communicate with Earth. The first conjunction is expected to occur for 10 days in September 2024.
Approach to Asteroid Psyche
The spacecraft’s slow, careful approach to the asteroid Psyche is expected to begin in May 2029, allowing the team to make refinements based on what they discover about the asteroid’s gravity field, shape, and spin. This phase starts about 100 days before the spacecraft initiates its first orbit designed for gathering science data (Orbit A).
Psyche’s imager will play a key role during the approach, providing images for navigation as well as for science. The first image for optical navigation, when asteroid Psyche will appear as a speck of light only a few pixels wide, is expected in early May 2029.
Using its gentle solar electric propulsion system, the spacecraft will position itself to be captured by the asteroid’s gravity. This is expected to occur in late July 2029. By the time spacecraft has been captured by the asteroid’s gravity, the asteroid Psyche will have gone from appearing as just a few pixels in an image to being about 500 pixels across in what will be the first close-up images of this metal-rich world.
Over the next 20 days, the Psyche spacecraft will maneuver into its first of four orbits. By that point, the final checkouts and calibration of all three science instruments and the gravity science investigation will be complete. Now the mission can study the asteroid.
If all goes as planned, the mission’s orbital operations phase will start in August 2029, lasting at least 26 months. Through a series of circular orbits that go lower and then higher in altitude around Psyche, which is about 173 miles (280 kilometers) at its widest point, the spacecraft will map the asteroid and gather science data. (Read about the main science goals of the mission in the science section.)
The orbits are named alphabetically by highest (A) to lowest (D), but they don’t proceed in alphabetical order. Rather, they proceed based on the changing amount of sunlight illuminating the asteroid’s surface during observation and the kind of science that can be done. The mission has also built buffer (“margin”) into its orbital operations timeline in case engineers need to address operational issues. The timing below should be considered approximate and subject to change as the team visits this unexplored world.
Orbit A, the first orbit, is expected to last about 56 days, from August to October 2029, at about 441 miles (709 kilometers) above the surface. The mission will focus on imaging and mapping the asteroid while taking magnetic field and gravity measurements.
Between each orbit, the spacecraft will need to change altitudes. During the first “transfer” after Orbit A, Psyche will take 17 days to descend to 188 miles (303 kilometers) above the surface for the first segment of Orbit B in late October 2029.
During Orbit B, the mission will focus on mapping the topography and geology of at least 80% of the asteroid while also continuing to assess the asteroid’s magnetic field and gravity. Because sunlight will illuminate less and less of the asteroid’s surface when the first part of Orbit B begins, this orbit is split into two parts, B1 and B2, so that the spacecraft can complete its mapping requirement. Orbit B1 will last about 92 days, until late January 2030. The spacecraft will return to the same altitude for B2 in May 2031, when more of the asteroid is bathed in sunlight again.
The mission will take up to 98 days to transfer to Orbit D, the lowest in altitude, which brings the spacecraft within 47 miles (75 kilometers) of the asteroid’s surface. At the same time, Orbit D marks a shift from a course that generally goes around the asteroid’s poles to one that generally travels around its equator. This orbit will help the mission focus on measuring the asteroid’s composition. The spacecraft will also map the asteroid and study its gravity and magnetic field. With about a month built in as a buffer, Orbit D is expected to start in May 2030 and last about 100 days.
Transferring into Orbit C in mid-January 2031 (based on current expectations), at an altitude of 118 miles (190 kilometers), the spacecraft will shift back to an orientation around the asteroid similar to Orbits A and B. This orbit will measure topography and perform the highest-priority magnetic field and gravity measurements of the prime mission.
At this point, when sunlight returns to illuminating about 80% of the asteroid’s surface, the spacecraft will move into Orbit B2, traveling around Psyche at an altitude of 188 miles (303 kilometers) for about 100 days.
The Psyche team has built in an additional 67 days of margin at the end of the prime mission that can be used to provide extra time for unexpected operational needs or science gathering. Psyche’s prime mission is currently anticipated to end on Nov. 1, 2031.