# Rendezvous with 16 Psyche

NASA's Psyche mission: launch, solar electric cruise, Mars gravity assist, rendezvous navigation, the orbit campaign at the metal\-rich asteroid, its instruments and data return

By Ham Sandwich

Topic: Space

[Open the interactive Jig](https://ask.jig.com/j/BHQNrSRbJSdD)

## Guide

### 1. Rendezvous with 16 Psyche

Asteroid 16 Psyche orbits the Sun at a semi\-major axis of 2\.92 AU, in the outer main belt between Mars and Jupiter\. It measures about 280 by 232 km, and current estimates put its metal content at 30 to 60 percent by volume\. NASA's Psyche spacecraft will be the first to visit a metal\-rich world and test whether it is the exposed core of an early planetesimal\.

Discovered by Annibale de Gasparis on 17 March 1852; it rotates in just over 4 hours\. Drag empty space to turn the view; pinch or scroll to zoom\.

### 2. Launch: 13 October 2023

A Falcon Heavy lifted Psyche from Launch Complex 39A at Kennedy Space Center\. The planned route covers about 3\.6 billion km in nearly six years: thrusting outward, a Mars gravity assist in May 2026, and arrival at Psyche in mid\-2029\. Fly the cruise and follow the dated marker along the path\.

Orbit sizes are to scale\. Planet positions use mean orbital motion; the transfer path is drawn schematically between the published event dates\.

### 3. Solar electric propulsion

Psyche has no chemical main engine\. Four SPT\-140 Hall\-effect thrusters, firing one at a time, ionise xenon and accelerate it electrostatically: up to 240 mN at a specific impulse near 1,800 s, an exhaust speed of v\_e = I\_sp g\_0, about 17\.7 km/s\. The arrays deliver about 21 kW near Earth but only 2\.3 to 3\.4 kW at Psyche, close to the inverse\-square law\.

Rocket equation: Δv = v\_e ln\(m\_0 / m\_f\)\. With up to 1,085 kg of xenon on a 2,747 kg launch mass, the ideal budget is about 9 km/s\.

### 4. Mars gravity assist: 15 May 2026

Psyche passed roughly 4,500 km above Mars\. In the planet's frame the hyperbolic excess speed v∞ is unchanged; the flyby only rotates it by the turning angle δ, with sin\(δ/2\) = 1 / \(1 \+ r\_p v∞² / μ\) and μ\_Mars = 42,828 km³/s²\. Adding Mars's orbital velocity turns that rotation into a change of heliocentric speed and orbital plane without propellant\.

The readout uses an example v∞ of 3 km/s because the cited sources do not give Psyche's value\. Lower passes bend the path more\.

### 5. Calculating a rendezvous

A flyby only has to reach a point; a rendezvous must match the target's position and velocity at the same instant\. Designers solve this two\-point boundary\-value problem \(Lambert's problem for coasting arcs\) and, for electric propulsion, optimise a continuous thrust profile with margin for missed thrust\. Navigators then refine the orbit from Deep Space Network range and Doppler data\.

In April 2025 a xenon\-line pressure drop paused thrusting\. After a switch to the backup line, full thrusting resumed on 16 June 2025 and the 2029 arrival held\.

### 6. Where is Psyche now?

The tracker opens on 15 October 2026: about five months past the Mars flyby, still thrusting outward toward the belt\. Drag the date to follow the spacecraft from launch to arrival; the readout gives its distance from the Sun and the one\-way light time to Earth\.

The marker follows the published timeline on a schematic path\. NASA's Eyes on the Solar System shows the live navigation ephemeris\.

### 7. Arrival and the orbit campaign

Psyche's mass is only about 2\.4 × 10¹⁹ kg \(GM ≈ 1\.6 km³/s²\), so orbits are slow: T = 2π √\(r³ / GM\)\. The spacecraft is planned to spiral down through four science orbits, from Orbit A at 700 km \(32\.8 h\) to Orbit D at 75 km \(3\.6 h\), over roughly 26 months\.

Planned order: A, B, D, C, then B again\. The spacecraft is drawn about 700 times larger than true scale beside the asteroid\.

### 8. What the instruments measure

Twin multispectral imagers map shape, topography and surface colour\. The gamma\-ray and neutron spectrometer measures elements such as iron, nickel, silicon and potassium from radiation excited by cosmic rays, best from low Orbit D\. Two magnetometers on the boom look for remanent magnetism from an ancient core dynamo, and X\-band radio tracking maps the gravity field and interior\.

Choose an investigation: its hardware on the spacecraft is highlighted and its measurement drawn\.

### 9. Sending the data home

Science data return over X\-band through the fixed 2 m high\-gain antenna to the Deep Space Network\. The signal travels at the speed of light, 499 s per astronomical unit, so at 3 to 4 AU each one\-way trip takes 25 to 33 minutes\. Psyche also carried DSOC, a laser communication demonstration that returned 267 Mbit/s in December 2023\.

Turn the scene to see the Sun\-facing arrays and the antenna aimed toward Earth\.