Introduction

Introduction

The Psyche spacecraft’s 280-million-mile (450-million-kilometer) voyage to its namesake asteroid could almost be considered a journey to the center of the Earth. Asteroid Psyche might be exposed core material of a differentiated planetesimal – that is, one that had begun to separate into layers. It then might have been stripped of its outer layers by violent collisions during our solar system’s early formation.

If it is, asteroid Psyche can offer a close look at the interior of terrestrial planets like our own that is normally hidden beneath layers of mantle and crust. And clues to the smashing and pummeling it endured long ago could sharpen insights into the formation of our solar system – as well as planetary systems around other stars.

The Psyche spacecraft will give us more than a glimpse of our deep past; we could see the beginnings of our technological future. Instead of traditional rocket fuel, Psyche will gradually build up speed using ion propulsion. Electricity from the space probe’s solar panels will power a new type of thruster, called a Hall thruster, for the first time in deep space. Xenon gas is converted to xenon ions, which are expelled from the spacecraft to provide thrust – slow at first, but building steadily as Psyche accelerates.

Even Psyche’s communications could break new ground. While relying on its more traditional primary communications system, the spacecraft includes a technology demonstration: testing laser communication, which encodes its messages on photons – particles of light – instead of radio waves. That potentially means transmitting far more data back to Earth in a given amount of time.

Psyche will take a swing past Mars for a gravitational push during its 3.5-year cruise to the asteroid, then spend 21 months measuring and mapping, gradually tightening its orbit until it passes just above the surface. Buckle up for an exciting ride.

Psyche in High Bay
The Psyche spacecraft undergoing system integration and testing on Aug. 18, 2021, at NASA's Jet Propulsion Laboratory (JPL) in Southern California. Credit: NASA/JPL-Caltech | Full image and caption
Spacecraft

Spacecraft

Spacecraft size: Park a Smart Car in the middle of a singles tennis court, and you’ll have a good sense of the Psyche spacecraft’s size. With its solar panels deployed at 81 feet (25 meters) by 24 feet (7.3 meters), Psyche would just about cover the tennis court. But the actual body of the spacecraft, at 10 feet (3.1 meters) by 8 feet (2.4 meters), is a little larger than the Smart Car.

Propulsion: Psyche’s large solar panels power its ion drive, reducing the need to carry bulky fuel supplies. Electricity from the solar panels is used to convert the fuel source – xenon gas – to xenon ions. As the ions make their exit they provide thrust, giving off a bluish glow. Swinging by Mars also will give Psyche a gravitational push toward its destination.

Science Instruments

Science Instruments

Multispectral Imager: High-resolution imagery, combined with filters, allows this instrument to identify the metals and silicates, or rocky materials, that make up asteroid Psyche. Powerful twin cameras will gather data on the asteroid’s geology, composition, and topography. One of the cameras will also assist with optical navigation.

Psyche Gamma Ray Spectrometer
The Psyche gamma-ray spectrometer uses a high-purified germanium crystal to capture gamma rays emitted by asteroid Psyche. These gamma rays can reveal what elements the surface is made of. Credit: Johns Hopkins/APL/Ed Whitman | Full image and caption

Gamma Ray and Neutron Spectrometer: Two detectors, one each for gamma rays and neutrons, will unmask the chemical elements on asteroid Psyche’s surface: iron, nickel, silicon, and oxygen. Their presence, abundances, and energies can tell the story of the asteroid’s formation, and its evolution over eons.

Magnetometer: One of the best ways to read the interior of a space body is to measure its magnetic field. These weaken as the body cools over time; whatever remains of asteroid Psyche’s magnetic field will reveal much about its history and composition.

Science Investigations

Science Investigations

Radio science: High-precision measurements of Psyche’s gravitational field, using the spacecraft’s X-band radio telecommunications system, will be combined with maps of the asteroid’s topography derived from imagery. Together, the measurements will show the bumps and dips in the asteroid’s gravitational field, revealing its interior structure.

Deep Space Optical Communication (DSOC): Communication via lasers sounds like science fiction, but on the Psyche spacecraft, science fiction gets a promotion to reality. The DSOC system encodes its data on photons, or particles of light, not on commonly-used radio waves. This is a test of new technology, expected to allow Psyche – and perhaps future missions – to pack far more information into its transmissions to Earth over an equal span of time using radio waves.

Timeline

Timeline

2011 Team begins work on the mission concept.

2014 Team begins writing the first proposal.

September 2015-Fall 2016 Mission Proposal

After NASA chooses Psyche for a Phase A concept study, a large team of scientists, engineers, project managers, and others produce a 1,000-page document. The team presents the mission proposal to 30 NASA reviewers during a “site visit” at Maxar Technologies, where the spacecraft would be built.

January 2017 NASA selects Psyche as the 14th mission in the agency's Discovery program.

January 2017 - May 2019 Assembly Approval

After completing a project and flight system preliminary design review, the Psyche team receives official approval to move to the next phase of design: fabrication and assembly (known as Phase C).

May 2019-January 2021 Instrument Construction

Science and engineering teams build Psyche’s three key instruments: a magnetometer, a multispectral imager, and a gamma ray and neutron spectrometer.

January 2021 Final Assembly and Testing

The Psyche team begins its next phase (known as Phase D): final assembly and testing of the instruments and the spacecraft at NASA’s Jet Propulsion Laboratory in Southern California, moving the spacecraft to its launch site, and the launch itself.

May 2022 Shipping for Launch

The team conducts an Operations Readiness Review, ensuring readiness for spacecraft operations, procedures, supporting software, and personnel. The spacecraft is then shipped to its launch site.

August 2022 Psyche Launch Period Opens

The spacecraft is scheduled to launch from Kennedy Space Center atop a SpaceX Falcon Heavy rocket.

October 2022-October 2026 Solar-electric Cruise – with Mars Assist

The Psyche spacecraft will cruise toward the asteroid under solar-electric power, including a swing by Mars for a gravity assist in May 2023.

January 2026 Arrival

The spacecraft is scheduled to arrive at its namesake asteroid, Psyche, after a 100-day approach phase that includes measurement of Psyche’s spin axis and rotation.

January 2026-October 2027 Tightening Orbits

The planned 21-month orbit of Psyche is really four successively closer orbits, allowing the onboard instruments to maximize their effectiveness at different distances. The data they send back are analyzed by the mission science team on Earth.

November 2027-August 2028 Mission Closeout

The Psyche spacecraft will provide its final data, the mission team will provide remaining deliverables, and the space flight systems will be decommissioned as the mission is closed out.

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