The Design, Verification, and Performance of the James Webb Space Telescope

Abstract

The James Webb Space Telescope (JWST) is NASA’s flagship mission successor to the highly successful Hubble Space Telescope. It is an infrared observatory featuring a cryogenic 6.6 m aperture, deployable Optical Telescope Element (OTE) with a payload of four science instruments (SIs) assembled into an Integrated Science Instrument Module (ISIM) that provide imagery and spectroscopy in the near-infrared band between 0.6 and 5 μm and in the mid-infrared band between 5 and 28.1 μm. JWST was successfully launched on 2021 December 25 aboard an Ariane 5 launch vehicle. All 50 major deployments were successfully completed on 2022 January 8. The observatory performed all midcourse correction maneuvers and achieved its operational mission orbit around the Sun–Earth second Lagrange point (L2). All commissioning and calibration activities have been completed, and JWST has begun its science mission. This paper will provide a description of the driving requirements and their technical challenges, the engineering processes involved in the design formulation, the resulting observatory design, the verification programs that proved it to be flightworthy, and the measured on-orbit performance of the observatory. Since companion papers will describe the details of the OTE and SIs, this paper will concentrate on describing the key features of the observatory architecture that accommodates these elements, particularly those features and capabilities associated with accommodating the radiometric and image-quality performance.

JWST's TEMPLATES for Star Formation: The First Resolved Gas-phase Metallicity Maps of Dust-obscured Star-forming Galaxies at z ∼ 4

“…The launch of JWST and its successful commissioning (Rigby et al 2023a(Rigby et al , 2023bGardner et al 2023;McElwain et al 2023;Menzel et al 2023) have transformed our ability to study galaxy formation and evolution, and we are now entering a new era for extragalactic astronomy. JWSTʼs Near-Infrared Spectrograph (NIRSpec; Böker et al 2023) can study highredshift galaxies at sub-kpc spatial resolution, offering a vast improvement over previous ground-based (and therefore seeing-limited) studies.…”

Lessons learned from systems engineering on the James Webb Space Telescope

“…This can most easily be illustrated in the various trades to address the mass margin recovery. 8 For example, there were many subsystem options that minimized the mass of the subsystem within their requirements but that used options that were less than desirable for the system perspective. One such option was the elimination of one reaction wheel assembly (RWA).…”

“…For a highly integrated architecture, it should be the system team that makes the final decision, based on the systems level performance assessments or presents this trade to a board of system level program management, mission assurance, and systems engineering for programmatic and risk-based trades. This can most easily be illustrated in the various trades to address the mass margin recovery 8 . For example, there were many subsystem options that minimized the mass of the subsystem within their requirements but that used options that were less than desirable for the system perspective.…”

Designing a new, large, complex observatory: learning the strategic lesson of newness from our experience on the James Webb Space Telescope

“…Verification has been part of program development on Webb from the early development through to the present. 17,18 Moreover, the link between design and verification has been recognized as critical to enterprise of space telescopes for long time. 19 The verification architecture used on Webb can be described as a modified "test as you fly" approach, where possible traditional methods of verification were used.…”