The IMAP Observatory Overview

Abstract

NASA's Interstellar Mapping and Acceleration Probe (IMAP) mission simultaneously investigates the acceleration of particles expelled from the Sun, and how the interaction of these particles with the local interstellar medium shapes our heliospheric boundary. The IMAP observatory makes critical measurements that facilitate this ground breaking science by incorporating a spin stabilized spacecraft orbiting around the first Sun-Earth Lagrange point, L1, with a payload comprised of ten unique instruments, making comprehensive and synergistic observations of solar wind, suprathermal, energetic particles and magnetic field, energetic neutral atoms mapping the boundary of our heliosphere, as well as interstellar neutral atoms and dust. This paper provides details on the design, integration, and testing of the IMAP observatory.

Fig. 1

The nominal IMAP trajectory from launch through end of the Baseline Mission. The first Trajectory Correction Maneuver (TCM) is performed 36 hours after launch. Four additional TCM’s are planned if the trajectory of the Observatory requires them to be performed. 107 days after launch and insertion, the Lissajous Orbit Insertion maneuver is performed. IMAP launched on September 24, 2025

Fig. 2

IMAP Operations Architecture Diagram. IMAP has simple, repeatable nominal operations for the Observatory. Spacecraft operations are run from the Mission Operations Center at the Johns Hopkins University Applied Physics Laboratory, which focuses on spacecraft health, Mission Design (MD), navigation (NAV), maneuver planning and housekeeping and telemetry data archiving. The MOC is also the primary interface to NASA Deep Space Network (DSN) for ground station coverage, which leverages 34 m Beam Waveguide (BWG) antennas. The IMAP instruments are operated from the Science Operations Center (SOC) at LASP (University of Colorado Boulder Laboratory for Atmospheric and Space Physics). This includes instrument commanding and instrument data arching. The SOC is also responsible for producing and disseminating science data products back to the IMAP science team. When not in DSN contact, IMAP is broadcasting Active Link for Real Time (I-ALiRT) space weather data to participating ground stations

Fig. 3

IMAP Observatory. The IMAP Observatory is an open bay structure that hours the spacecraft subsystems, and accommodates 10 science instruments. The top left picture shows the configuration with the solar arrays installed, and the bottom picture shows a view with the entire top deck “removed” to view the various major components, subsystems, and instruments that comprise IMAP. The table included identifies key performance characteristics

Fig. 3

IMAP Observatory. The IMAP Observatory is an open bay structure that hours the spacecraft subsystems, and accommodates 10 science instruments. The top left picture shows the configuration with the solar arrays installed, and the bottom picture shows a view with the entire top deck “removed” to view the various major components, subsystems, and instruments that comprise IMAP. The table included identifies key performance characteristics

Fig. 4

IMAP System Block Diagram. Shown here are the major subsystems of the IMAP Spacecraft, including the Avionics, RF, Electrical Power System, Attitude Control System, Propulsion, Mechanical, Thermal, and Harness. Connections to the IMAP Payload are shown as well

Fig. 5

IMAP ACS Block Diagram. Shown above is the IMAP Attitude Control System. The system is comprised of 2 Star Trackers and 2 Digital Sun Sensors with accompanied electronics, as well as 12 4.4 N thrusters and 2 nutation dampers. The ACS also includes a ground component comprised of its algorithms and truth model that support maneuver planning efforts

Fig. 6

IMAP Avionics Block Diagram. Shown above are the 5 electronics cards slices of the IMAP Integrated Electronics Module, representing the Avionics subsystem. Two SCIF cards split the duties to interface to the instruments of the IMAP Payload, the TAC card interfaces to the propulsion system thrusters. The Single Board Computer houses the Solid State Recorder, and the DC/DC board feeds 5 V power to the other cards

Fig. 7

IMAP EPS Block Diagram. Shown above is the overall electrical power architecture for IMAP. The Solar Arrays provide power to the Power System Electronics, which serves as the main power interface for IMAP (including connecting to the battery). The PSE provides the main bus power to the PDU, which is then responsible for distributing power at appropriately specified levels to all Observatory loads

Fig. 8

IMAP Propulsion Subsystem Block Diagram. There are 4 total axial thrusters (2 on the top deck and 2 on the bottom deck), and 8 total radial thrusters (4 in Bay E, 4 in Bay B). 3 hydrazine tanks are housed in the main body of the spacecraft

Fig. 9

IMAP Radio Frequency Subsystem Block Diagram. The RF subsystems is comprised of a Low and Medium Gain Antenna, an X-band Frontier Radio, and a Solid State Power Amplifier. The Low Gain Antenna is only planned to be used during launch and ascent, with the Medium Gain Antenna planned to be used for all other operations

Fig. 10

IMAP Thermal Design. Given the open bay structure of the spacecraft, MLI is used to close out the spacecraft panels and provide thermal accommodations to the components in the spacecraft bays. The above figure shows which components of IMAP are coupled vs isolated from the spacecraft structure

Fig. 11

IMAP Payload Block Diagram. The IMAP Payload is comprised of 10 Instruments (IMAP-Ultra, IMAP-Hi, IMAP-Lo, CoDICE, HIT, SWE, SWAPI, IDEX, GLOWS, and a Magenetometer. Primary power to all instruments in provided from the Spacecraft. The above figure illustrates which of the Instruments have both high and low voltage systems for acquiring science data measurements. IMAP-Ultra and IMAP-Hi each have two instruments on board, with one pointed at 90 degrees relative to the +X axis, and one pointed 45 degrees. IMAP-Lo is unique in that it has a dedicated pivot platform for taking measurements at different angles

Fig. 12

IMAP Observatory at the NASA MSFC XRCF. The top figure is a CAD model of IMAP on the rails that allow entry into the XRCF chamber. The lower figure is a picture of the IMAP Observatory in its final test instrumentation state prior to closure of the XRCF chamber door to begin TVAC

Fig. 12

IMAP Observatory at the NASA MSFC XRCF. The top figure is a CAD model of IMAP on the rails that allow entry into the XRCF chamber. The lower figure is a picture of the IMAP Observatory in its final test instrumentation state prior to closure of the XRCF chamber door to begin TVAC

Fig. 13

IMAP, and its two rideshare payloads, SWFO-L1 and Carruthers Geocorona Observatory, on the LV Payload Adapter and ESPA port just prior to fairing encapsulation at Astrotech Space Operations

Fig. 14

(Top) The Falcon 9, vertical at the 39A Launch Complex at Kennedy Space Center. (Bottom) Lift off of IMAP from Launch Complex 39A on September 24, 2025