JWST Solar System Science

James Webb Space Telescope (JWST) – Solar System Science

The James Webb Space Telescope (JWST) Solar System Science Group serves both the Guaranteed Time Observing (GTO) program team of Dr. Heidi Hammel (AURA) as well as General Observing (GO) investigators with Solar System time and some aspects of the Jupiter ERS Program led by Imke de Pater and Thierry Fouchet. The group consists of members from many institutions across the world, all with the common goal of utilizing the power of JWST for the exploration of our own solar system.

One of JWST’s four main science themes is Planetary Systems and the Origins of Life. A fundamental aspect of this theme is using JWST to study objects in our own Solar System. The observatory is capable of observing everything from Mars out. From the bright atmospheres of the Giant Planets to the small Kuiper Belt Objects (KBO) that exist in the cold expanses beyond Neptune. JWST will have the sensitivity to obtain near-infrared spectra and mid-infrared photometry (albedos) of any KBO known today. It will be able to monitor planetary (and satellite) weather for the duration of the mission (minimum 5 years, probably > 10 years) in two intervals of about three months each year. The JWST was built with the fast-moving and relatively bright objects of our solar system in mind.

JWST will be highly complementary to a number of solar system missions as well as provide some foundation for planning future missions. JWST offers high sensitivity and angular resolution at near-infrared and mid-infrared wavelengths. This includes imaging and spectroscopic coverage from 0.6 to 28.5 microns with low to moderate spectral resolving power (~100 to a few thousand). Many important molecules (e.g. H2O, HDO, CO, CO2, S2, CH4), ices, and minerals have strong features in the JWST wavelength range.

James Webb Sapce Telescope in our Solar System

Image credit: NASA/GSFC

The approved GTO programs for Solar System science span a multitude of science topics:

Capabilities of James Webb Space Telescope

The design of the James Webb Space Telescope restricts what can be observed in the inner Solar System. Objects must be more than 85 degrees from the Sun as viewed from L2, which includes Mars, Jupiter, Saturn, their satellites, the main asteroid belt, and all outer Solar System objects - even some Near-Earth Asteroids! JWST also can’t look farther from the Sun than 135 degrees (i.e., within 45 degrees of the anti-Sun position) but outer solar system objects will all be observable some of the time. The field of regard limitations are a fundamental consequence of the observatory thermal design and the sunshield design that keeps the telescope and instruments cold. This means that the Sun, Earth, Moon, Mercury, and Venus cannot be observed.

James Webb Space Telescope's Observations Within our Galaxy

Currently, JWST offers tracking rates for moving targets up to 30 mas/s. This will enable observations of Mars at its fastest rate of motion as well as many small bodies. However, some objects are significantly faster at their optimal observation windows (e.g. Near-Earth Objects, comets approaching perihelion, interstellar objects), so the JWST project aims to test faster rates during commissioning to verify the integrity of observations and possibly offer this new capability in future cycles.

James Webb Space Telescope's Imaging and Spectroscopy Wavelengths

JWST has Four Instruments:

  1. The Near InfraRed Spectrograph (NIRSpec) will do spectroscopy between 0.6 and 5 microns
  2. The Mid-Infrared Instrument (MIRI) has both a camera and a spectrograph that covers the wavelength range of 5 and 28 microns
  3. The Near Infrared Camera (NIRCam) is the JWST’s primary imager and will operate over a wavelength range of 0.6 to 5 microns
  4. The Fine Guidance Sensor/Near Infrared Imager and Slitless Spectrograph (FGS/NIRISS) is the combination of a “guider” that allows the JWST to point precisely and a specialized instrument that has a wavelength range of 0.8 to 5 microns.
James Webb Space Telescope's Resolution Elements for Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto

The JWST Guaranteed Time Observation Programs for Solar System Science

Guaranteed Time Observation (GTO) programs are awarded to the science teams that contributed significantly to the design and management of key hardware and software components of JWST and/or helped plan the observatory’s scientific mission. Across the first 3 cycles of telescope operation (2022-2025), roughly 16% of available observing time will be dedicated to GTO programs, spanning the full range of JWST science.

Cycle 1 GTO programs focused on Solar System science include detailed time-resolved compositional mapping of the Martian surface, short- and medium-term climate monitoring of the giant planets, and exploratory spectroscopic studies of the full menagerie of asteroids and comets, from near-Earth objects to the Kuiper belt. These programs are designed to be benchmark observations for the JWST mission, and most have no proprietary period, ensuring that the data will be made available to the wider astronomical community immediately.

Full list of approved Cycle 1 GTO programs

NASA Logo, National Aeronautics and Space Administration