Featured Image: John Pisani / Cosmic Perspective
|October 13, 2023 – 14:19:43 UTC | 10:19:43 EDT|
|Falcon Heavy; B1064-4 (MY), B1065-4 (PY), B1079-1 (center); 76.47, 76.47, and N/A day turnaround time, respectively|
|LC-39A, Kennedy Space Center, Florida, USA|
|2,747 kg (~6,056 lbs)|
Where did the spacecraft go?
|Escape trajectory to Asteroid 16 Psyche, arriving at it in August 2029|
Did they attempt to recover the first stage?
|Partially, the side boosters were recovered, but the center core was expended|
Where did the first stage land?
|The side boosters softly touched down on Landing Zone 1 and 2 (LZ-1 & LZ-2); the center core splashed down in the Atlantic Ocean|
Will they be attempting to recover the fairings?
|Yes, the fairing halves were recovered from the water ~1,543 km (~959 mi) downrange by Bob|
Were these fairings new?
|Yes, the fairing was not flight proven|
This was the:
|– 1st Falcon Heavy launch for an interplanetary mission|
– 8th Falcon Heavy launch
– 4th Falcon Heavy launch in 2023
– 205th and 206th re-flight of a booster
– 71st and 72nd re-flight of a booster in 2023
– 233rd and 234th booster landings
– 159th and 160th consecutive landing (a record)
– 72nd launch for SpaceX in 2023
– 70th SpaceX launch from LC-39A
– 165th orbital launch attempt of 2023
Where to watch
Tim Dodd, the Everyday Astronaut’s replay. Streaming started at T-45 minutes, with questions and conversation live!
What’s All This Mean?
SpaceX prepares to launch the Psyche probe into a journey to a metal world: the asteroid 16 Psyche. This is the first scientific probe that intends to visit such a celestial body. To that end, the payload travels atop a Falcon Heavy rocket, aiming at an escape trajectory.
Historical Launch Complex 39A, at Cape Canaveral Space Force Station, in Florida, will see the launcher take to the skies. Afterward, the launch vehicle will follow a trajectory due east-southeast, taking considerable advantage of Earth’s rotation.
As has been happening during the latest launches of this vehicle, SpaceX will not recover its center core that will crash into the ocean. Conversely, both side boosters will return to land close to the launch site. The fairing halves will also be recovered for potential later reuse. If liftoff could not take place, additional instantaneous launch windows exist from now until October 25.
How Did It Go?
As planned, the Falcon Heavy lifted off on time from Kennedy Space Center’s LC-39A. The rocket pitched over, and went through the maximum aerodynamic pressure without issues. The flight continued nominally, with both side cores separating and returning to their designated landing zones. Both of them touched down as expected, achieving like this secondary mission success. Later, the central core separated, passing the torch over to the second stage, and later falling to the ocean. Fairing deployment took place as expected, and, after completing a total of two burns with this stage, Psyche separated at ~15:22 UTC. This marked primary mission success. Both the stage and the spacecraft entered a hyperbolic orbit of 794x -36,991 km and 30.1 degrees inclination. After October 16, they should leave Earth’s sphere of influence and enter a 1.0×2.5 AU Solar orbit.
What Is The Psyche Mission?
Through its Discovery Program, on January 4, 2017 NASA selected a mission to study the 16 Psyche asteroid, which christened both the endeavor and the spacecraft. This was the 14th selectee of the program, with Lucy being the 13th, both selected on the same day and aimed at asteroids. However, Psyche’s origins date back to 2011, when the team at the Arizona State University (ASU) began conceiving it.
Years later, in September 2015, NASA selected Psyche for a detailed concept study. After extensive work, NASA received the resulting ~1,000-pages long document for assessment. This took place in August 2016, and in November of the same year a site visit from the agency served to thoroughly present the mission.
Once selected, ASU would lead the mission. Its management, operations, and navigation would become the responsibility of the Jet Propulsion Laboratory (JPL). Additionally, Maxar would be in charge of the manufacturing of the solar-electric propulsion (SEP) chassis, which would host the payloads, or instruments.
NASA’s Discovery Program
The present mission came to be thanks to this program, through which NASA funds focused science research. While other programs, such as New Frontiers or Flagship, feature a broader scope, Discovery centers its goals in Solar System-related studies. That is, scientists design and propose a mission, and receive the resources to carry it out, after approval.
Discovery strives to accomplish great science by bringing together smaller missions, framed inside not-to-exceed budgets, and with shorter lead times. Missions born from this program ensure particular pressing questions regarding planetary science receive an answer. In turn, addressing these queries guarantees a stream of new scientific data on these topics.
Asteroid 16 Psyche
Sixteen Psyche is a large M-type asteroid located in the main asteroid belt between Mars and Jupiter and is believed to be the largest and most massive M-type asteroid. It has a mean diameter of roughly 220 kilometers and masses 2.29×1019 kilograms. It is in a 2.53 AU by 3.32 AU orbit around the sun inclined 3.096 degrees, with an orbital period of 4.999 years.
Sixteen Psyche was discovered by Italian astronomer Annibale de Gasparis on March 17, 1852, and named the asteroid after the Greek goddess Psyche. Upon discovery, it was hypothesized to be the exposed core of a protoplanet, but more recent studies have shown this to be likely false. The asteroid is composed mainly of iron and nickel instead of silicate rocks, which make up the majority of other asteroids. Additionally, it has an irregular, potato-like shape and a mean density of 3.97 g/cm3. This corresponds to a surface gravity of 0.144 m/s2.
Science By Psyche
The Psyche mission aims to explore Asteroid 16 Psyche, which is believed to be the exposed nickel-iron core of an early planet.
- Understand a previously unexplored building block of planet formation: iron cores. The spacecraft will use its gamma ray and neutron spectrometers to measure the elemental composition of the asteroid, which will help determine whether Psyche is a protoplanetary core or just an unmelted material. On top of this, Psyche’s magnetometer will look for evidence of a magnetic field around the asteroid, which would be strong evidence that the asteroid formed from the core of a planetary body.
- Look inside terrestrial planets, including Earth, by directly examining the interior of a differentiated body, which otherwise could not be seen. Psyche’s multispectral imager will capture high-resolution images of the asteroid’s surface, which will help the team of scientists behind the mission determine the relative age of different regions on Psyche’s surface. The X-band gravity science investigation will measure Psyche’s gravity field to determine its mass distribution and the structure of its interior.
- Explore a new type of world: for the first time, the spacecraft will examine a world made not of rock and ice, but of metal. As mentioned above, the gamma-ray and neutron spectrometers on the spacecraft will measure the asteroid’s molecular makeup, which then will be used alongside high-resolution images of the surface to understand the topography of the asteroid.
Instruments On Board
Psyche carries three instruments to space in order to accomplish its science tasks. Additionally, the high gain antenna will perform, not only communication but also gravity measurements. Besides them, there is also a technology demonstration flying aboard the spacecraft.
MSI — Multispectral Imager
Two identical cameras provide high-resolution images to study different aspects of the asteroid. Particularly through the imager, the spacecraft will study the asteroid’s geology, its composition, and its topography. Using both filters and lenses they can differentiate between metals and silicates on Psyche’s surface. Additionally, the redundancy offers a second usage for the cameras, allowing for critical optical navigation.
The MSI is multispectral because it captures images in a range of light frequencies. That is, this instrument can see light that is visible for the human eye. Furthermore, it can also see infrared wavelengths, which remain invisible for humans.
GNSR — Gamma-Ray And Neutron Spectrometer
The elemental composition 16 Psyche is one of the spacecraft’s subject studies. Therefore, the spectrometer will enable the detection of the different substances that comprise this metal world. Not only this, but it will also be capable of discerning how common they are, how many of them there are, and where. Its installation on a 2-meter boom moves the instrument away from the interactions of background radiation particles with the spacecraft. Hence, this should greatly diminish alterations to its observations.
During its orbit around the Sun, the asteroid finds itself under a radiation shower, in the form of cosmic rays and high-energy particles. Due to receiving all of this energy, the elements on this metal world’s surface emit neutrons and gamma rays in return. Because these emissions carry distinguishing characteristics, and the GNSR can interpret them, it will identify the superficial composition.
By means of two magnetometers, Psyche will attempt to measure any magnetic field that might still be present on the asteroid. To this end, a 2-meter boom has two separate attachment points planned. One of them is at mid-length, while the second one is at the boom’s farthest end.
Normally, asteroids do not generate magnetic fields, as this is a phenomenon derived from liquid metallic cores. For this reason, scientists intend to check if the magnetometer can find a remaining one. In case this happened, this would be good evidence 16 Psyche once was a planetary core.
Studying the asteroid’s gravity field will, in turn, allow a better understanding of its interior. That is why the X-band radio telecommunication system will aid in this task. Cross-checking will take place, combining these measurements with topography data, in order to obtain the previously mentioned information.
Once the X-band waves reach the ground stations back on Earth, it is possible to analyze them. Consequently, scientists can determine how the asteroid influences the spacecraft’s orbit. In turn, these observations reveal information such as 16 Psyche’s rotation, mass, and gravity field. Finally, this enables a better understanding of what is below this metal world’s surface.
DSOC — Deep Space Optical Communication
In addition to its suite of instruments, the Psyche spacecraft hosts this technology demonstration. A laser mounted on one side will encode information in the photons conforming its light beam, and shoot it back to Earth. Expectations are that the amount of data communicated between spacecraft and ground stations will be larger than using existing methods.
When the spacecraft went through its design phase, the team chose to profit from Maxar’s 30-year expertise in building Earth-orbiting satellites. On the other hand, JPL’s experience in robotic probes for deep space missions also aided the venture. The research and development center provides the main computer, flight software, fault-protection systems, and most of the telecommunications systems.
The boulder-based Maxar provides one of its all-electric platforms from the 1300-series. The solar electric propulsion (SEP) chassis represents its central piece. In addition to its structure, Maxar also supplies many subsystems: electric propulsion, power, and thermal. Sensors for the attitude control system (ACS) are further components provided by the firm, as well as the high gain antenna.
To reduce costs, the commercial components selected for Psyche are either standard or standard customizations. Examples of the former are the structure — made of composite materials — in its smallest and lightest version available for the 1300 buses, and a medium-sized solar array. The latter include supports for the magnetometers, for the HGA, for nitrogen tanks, for a sunshade for DSOC, and so on.
Final integration, tests, and launch operations are a responsibility of JPL. Furthermore, Arizona State University leads the mission. In summary, in a compound effort, these entities put together the ideal space vehicle to carry the previously mentioned instruments.
The spacecraft resembles a cube with an antenna dish and pair of booms — or structures to mount instruments — on the top surface, designated the +Z face. Particularly, this is the probe’s launch configuration. Psyche’s dimensions are the following: 4.9 m (16.1 ft) tall, which includes two booms 2 m (6.6 ft) long each, 2.2 m (7.1 ft) wide, and 2.4 m (7.8 ft) deep. Moreover, at launch it features a mass of 2,747 kg (6,056 lb). This is bound to change due to the detumbling maneuvers right after separating from the rocket.
However, once it is free from the launch vehicle, the probe deploys both solar arrays, considerably increasing its size. Once these are fully deployed, Psyche reaches 25 m (81 ft) in span, and 7.3 m (24 ft) in width.
Using Maxar’s electrical propulsion heritage as its base, Psyche adopts the SPT-140 Hall-effect ion thrusters from many satellites geostationary orbit (GEO).
However, flight conditions will be different in this scientific mission. This will demand lower power consumption during burns: from 3 kW for GEO, to 0.9 kW for deep space. Counterintuitively, this requires more propellant flow. As a result, the Psyche mission will have the largest xenon throughput of any space mission to date. Because of all of this, the commercial propulsion needed study and validation for this new application.
Psyche makes use of a total of four thrusters, with two of them on supports at the +X face, and the remaining two, at the -X face. It is worth noting, only one thruster fires at a time; also, both supports gimbal around two axes each. Seven tanks — composite overwrapped pressure vessels (COPVs) — store 155 kg (~340 lb) of gaseous xenon each, totaling 1,085 kg (~2,400lb). A series of pipes, valves, and other parts supply the thrusters with this propellant. Electrical power generates xenon ions from the gas, and also accelerates them, expelling them to create thrust: 240 mN (0.05 lbf) per thruster.
Psyche’s main propulsion system features low thrust, but high power consumption. Sometimes, the mission will require specific maneuvers that are power-critical, and time-critical. These are points in time such as after separation from the launch vehicle, for detumbling. Another case would be in contingencies when the solar arrays lost their alignment with the Sun. In those opportunities, a different kind of thruster better meets said needs.
Equipping the spacecraft, there are twelve nitrogen cold gas thrusters. Psyche’s faces +Z and -Z act as mounting structures for all of them. Despite their placement, they allow for rotation around all three axes. These are Moog 58E151 thrusters, connected to three tanks with a capacity of 82 liters (~22 gal) each. To generate thrust, their inlet receives the gas at ~2.4 MPa (350 psi). Consequently, they create a force of 0.5 N (~0.1 lbf) at a specific impulse of 70 s.
The spacecraft has two cross-shaped solar arrays attached to either Y face. Each of them consists of five panels, which in turn, comprise 65 strings of solar 35 cells each in most cases. Some of them only have 34 cells, due to geometry constraints. They generate the entirety of the power the probe needs to operate.
Once again, Psyche adapts GEO hardware — Maxar’s EPS 2.0 — to deep space conditions. Temperature and solar light intensity change as the spacecraft travels further away from the Sun. Thus, electric potential (voltage) and current coming from the solar cells modify their values with Sun-probe distance. For instance, close to Earth, the arrays produce 21 kW of power. Conversely, they will produce 2.3 to 3.4 kW while orbiting the target asteroid.
As a consequence, the system needs adequate electronics to manage the whole operational range. Finally, the teams expect the spacecraft to go through eclipses, or to operate in the shadow projected by 16 Psyche. That is why a single ~7.2 kW h Li-Ion battery is an important component of this system. In the same way, this feature becomes crucial in those moments when power requirements surpass the arrays’ generation.
GN&C — Guidance, Navigation, And Control
To achieve its navigation needs, the spacecraft will use star trackers capable of determining how it is pointing. Ring laser gyroscopes — commercial, the same as the star trackers — come into action for sensing any rotational speed. Four reaction wheels in a pyramid configuration serve as primary attitude control, enabling stabilization in three axes.
The system needs to be used throughout the mission, and, as can be seen, all of these elements are electrical. That is, no chemical propulsion supports the Psyche mission. As a result, to achieve control, the spacecraft combines the actions of the reaction wheels, electrical propulsion, and cold gas thrusters.
Most of the time, the reaction wheels offer attitude control, with the electrical propulsion creating torque to unload the wheels. Primary objectives of these subcomponents include pointing the solar arrays, as well as the thrust vector. In particular cases, the cold gas thrusters enter the scene, as previously mentioned. Other tasks that GN&C perform are:
- Detumbling the spacecraft following launch vehicle separation.
- Acquiring inertial reference.
- Pointing the high gain antenna (HGA) and DSOC payload for communications.
- Enabling flexible inertial pointing of the science instruments for checkouts, calibrations, and operations.
- Supporting spacecraft “safe mode” with fault protection functions.
- Implementing an Earth-pointed “standby” mode.
Psyche’s baseline software is JPL’s Flight Software Core Product Line (FSCPL), which is modular, or partitioned. This protects the probe from a failure propagating if only one module sees an error. The product is a development in collaboration with the Europa Clipper mission. It pulls heritage from the Soil Moisture Active Passive (SMAP) mission, and the Mars Science Laboratory (MSL) mission. As a whole, the GN&C subsystem is a joint effort between Maxar and JPL.
The present mission employs an X-band Small Deep Space Transponder and a 2.0 m (6.6 ft) high-gain antenna for communication with the Deep Space Network. Maxar provided the high-gain antenna, enabling uplink speeds of two kbps and downlink speeds of 180 kbps, even at distances beyond four AU. Three low-gain antennas support lower data transfer rates. The telecommunications equipment is a collaborative effort between Maxar and JPL, leveraging expertise from missions like Juno and Dawn.
Psyche’s thermal management system follows a design similar to Maxar’s GEO satellites. It incorporates heaters to prevent equipment from reaching minimum allowable temperatures and includes passive radiators placed on the -Y and +Y faces of the spacecraft to dissipate excess heat. Special isolation measures are implemented for the DSOC payload, ensuring that sensitive hardware remains within maximum allowable temperature limits.
Journey To Psyche
After being launched on Falcon Heavy, the spacecraft will undergo its post-launch assessment review. After this, the spacecraft will use its onboard electric propulsion thrusters to target Mars, where it will perform a gravity assist. During this maneuver, the spacecraft will intersect Mars’ orbit, which will therefore increase its speed. After this, the spacecraft will coast until arriving at Psyche. This will have taken place after:
- Having traveled 3.6 billion km (2.2 billion mi).
- Being in space for 6 years.
At 100 days before arrival, the mission officially will enter the “approach” phase. During this time, the spacecraft will measure the asteroid’s spin axis and rotation. The spacecraft will transition between four different orbits. The first orbit, “orbit A,” will last for 41 orbits/56 days and will be used to characterize the asteroid. Once this is complete, Psyche will lower its orbit into a Orbit B, which will be used for the topography measurements. This will last 192 days. Next, the orbit will be lowered, where it will spend 180 days making measurements of the body’s gravity. Finally, the spacecraft will change its orbital inclination and lower its orbit for the elemental mapping portion of the mission. This is expected to last 100 days.
After about 26 months orbiting the asteroid and carrying out science, the spacecraft will safely decommission itself. That is, it will remain in Psychean orbit as a moon of sorts to it. This is not a first, as the Dawn spacecraft ended its mission, and remained orbiting Ceres back in November 2018.
What Is The Falcon Heavy?
The Falcon Heavy first stage contains 27 Merlin 1D+ sea-level engines across three cores. Each engine uses an open gas generator cycle and runs on RP-1 and liquid oxygen (LOx). Each engine produces 845 kN of thrust at sea level, with a specific impulse (ISP) of 285 seconds, and 934 kN in a vacuum with an ISP of 313 seconds. Due to the powerful nature of the engine, and the large amount of them, the Falcon Heavy first stage is able to lose several engines right off the pad, or up to two later in the flight, and be able to successfully place the payload into orbit.
The Merlin engines are ignited by triethylaluminum and triethylborane (TEA-TEB), which instantly burst into flames when mixed in the presence of oxygen. During static fire and launch the TEA-TEB is provided by the ground service equipment. However, as the Falcon first stage is able to propulsively land, three of the Merlin engines (E1, E5, and E9) contain TEA-TEB canisters to relight for the boost back, reentry, and landing burns.
The Falcon Heavy second stage is the same as the Falcon 9’s. It contains a singular MVacD engine that produces 992 kN of thrust and an ISP of 348 seconds. The second stage is capable of doing several burns, allowing the Falcon to put payloads in several different orbits.
SpaceX is currently flying two different versions of the MVacD engine’s nozzle. The standard nozzle design is used on high-performance missions. The other nozzle is a significantly shorter version of the standard, decreasing both performance and material usage; with this nozzle, the MVacD engine produces 10% less thrust in space. This nozzle is only used on lower-performance missions, as it decreases the amount of material needed by 75%. This means that SpaceX can launch over three times as many missions with the same amount of Niobium as with the longer design.
For missions with many burns and/or long coasts between burns, the second stage is able to be equipped with a mission extension package. When the second stage has this package it has a gray strip, which helps keep the RP-1 warm, an increased number of composite-overwrapped pressure vessels (COPVs) for pressurization control, and additional TEA-TEB.
Falcon Heavy Boosters
The boosters that supported the Psyche mission were B1079-1 as the center core, the minus Y booster is B1064-4, and the positive Y booster is B1065-4. As the name implies, both side boosters had flown three previous missions and the center core was new. The side boosters previously flew as a set on USSF-44, USSF-67, and EchoStar 24.
Following stage separation, the Falcon Heavy side cores conducted three burns. These burns successfully allowed to softly touch down the boosters on SpaceX’s landing pads LZ-1 and LZ-2. The center core was expended.
Falcon Heavy Fairings
The Falcon Heavy’s fairing consists of two dissimilar reusable halves. The first half (the half that faces away from the transport erector) is called the active half, and houses the pneumatics for the separation system. The other fairing half is called the passive half. As the name implies, this half plays a purely passive role in the fairing separation process, as it relies on the pneumatics from the active half.
Both fairing halves are equipped with cold gas thrusters and a parafoil which are used to softly touch down the fairing half in the ocean. SpaceX used to attempt to catch the fairing halves, however, at the end of 2020 this program was canceled due to safety risks and a low success rate. On Psyche, SpaceX successfully recovered the fairing halves from the water with its recovery vessel Bob.
In 2021, SpaceX started flying a new version of the Falcon 9/Heavy fairing. The new “upgraded” version has vents only at the top of each fairing half, by the gap between the halves, whereas the old version had vents placed spread equidistantly around the base of the fairing. Moving the vents decreases the chance of water getting into the fairing, making the chance of a successful scoop significantly higher.
|– 00:53:00||SpaceX Launch Director verifies go for propellant load|
|– 00:50:00||1st stage RP-1 (rocket grade kerosene) loading begins|
|– 00:45:00||1st stage LOX (liquid oxygen) loading begins|
|– 00:35:00||2nd stage RP-1 (rocket grade kerosene) loading begins|
|– 00:18:30||2nd stage LOX loading begins|
|– 00:07:00||Falcon Heavy begins engine chill|
|– 00:00:59||Flight computer commanded to begin final pre-launch checks|
|– 00:00:45||SpaceX Launch Director verifies go for launch|
|– 00:00:20||Propellant tanks pressurize for flight|
|– 00:00:06||Engine controller commands engine ignition sequence to start|
|– 00:00:00||Falcon Heavy liftoff|
Psyche’s Launch, Landing, And Deployment
All Times are Approximate
|00:01:09||Max Q (Moment of peak mechanical stress on the rocket)|
|00:02:25||Side boosters engine cutoff (BECO)|
|00:02:28||Side boosters separate|
|00:02:40||Side boosters boostback burns begin|
|00:03:51||Side boosters boostback burns end|
|00:03:55||1st stage main engine cutoff (MECO)|
|00:03:59||1st and 2nd stages separate|
|00:04:04||2nd stage engine starts (SES)|
|00:06:47||Side boosters entry burns start|
|00:07:04||Side boosters entry burns end|
|00:08:00||Side boosters landing burns start|
|00:08:17||Side boosters landing|
|00:08:26||2nd stage engine cutoff (SECO-1)|
|00:54:00||2nd stage engine starts (SES-2)|
|00:56:12||2nd stage engine cutoff (SECO-2)|