The Lazuli Space Observatory: Architecture & Capabilities

TL;DR

The Lazuli Space Observatory introduces a 3 m, space-based optical–NIR facility designed for rapid-response observations and precision spectrophotometry, addressing a gap in time-domain and multi-messenger astronomy. Its architecture combines an off-axis TMA telescope with three instruments (WCC, IFS, ESC) to deliver 350–1700 nm coverage, diffraction-limited imaging, and high-contrast coronagraphy within a 3:1 lunar-resonant orbit, enabling ToOs within <4 hours (goal ~90 minutes). The paper outlines a mission-design philosophy that emphasizes rapid deployment, controlled risk, and open-data, and details the observatory’s architecture, capabilities, and concrete science cases spanning transient physics, exoplanets, and cosmology. By coupling hardware with software-enabled operations and community data access, Lazuli aims to accelerate discovery, provide a testbed for next-generation missions, and demonstrate a viable model for agile, high-impact space astronomy in the late 2020s.

Abstract

The Lazuli Space Observatory is a 3-meter aperture astronomical facility designed for rapid-response observations and precision astrophysics across visible to near-infrared wavelengths (400-1700 nm bandpass). An off-axis, freeform telescope delivers diffraction-limited image quality (Strehl $>$0.8 at 633 nm) to three instruments across a wide, flat focal plane. The three instruments provide complementary capabilities: a Wide-field Context Camera (WCC) delivers multi-band imaging over a 35' $\times$ 12' footprint with high-cadence photometry; an Integral Field Spectrograph (IFS) provides continuous 400-1700 nm spectroscopy at R $\sim$ 100-500 for stable spectrophotometry; and an ExtraSolar Coronagraph (ESC) enables high-contrast imaging expected to reach raw contrasts of $10^{-8}$ and post-processed contrasts approaching $10^{-9}$. Operating from a 3:1 lunar-resonant orbit, Lazuli will respond to targets of opportunity in under four hours--a programmatic requirement designed to enable routine temporal responsiveness that is unprecedented for a space telescope of this size. Lazuli's technical capabilities are shaped around three broad science areas: (1) time-domain and multi-messenger astronomy, (2) stars and planets, and (3) cosmology. These capabilities enable a potent mix of science spanning gravitational wave counterpart characterization, fast-evolving transients, Type Ia supernova cosmology, high-contrast exoplanet imaging, and spectroscopy of exoplanet atmospheres. While these areas guide the observatory design, Lazuli is conceived as a general-purpose facility capable of supporting a wide range of astrophysical investigations, with open time for the global community. We describe the observatory architecture and capabilities in the preliminary design phase, with science operations anticipated following a rapid development cycle from concept to launch.

Figures (15)

• Figure 1: Overview of the 3 m Lazuli Space Observatory and its three instruments, the Widefield Context Camera (WCC), the Integral Field Spectrograph (IFS), and the ExtraSolar Coronagraph (ESC). Main properties and characteristics of the telescope and the instruments are highlighted.
• Figure 2: Current model prediction for the as-built in-orbit image quality across the Lazuli focal plane. This accounts for surface figure (M1 through M4), residual alignment errors, and thermal distortion errors (M1) of the TMA telescope. a) Encircled energy versus radius at various field points compared to the diff. limit. Dashed vertical lines indicate the pixel size of the WCC sensors (red: Sony IMX 455; orange: HWK 4123). b) Wavefront error map in waves across the telescope focal plane with colorbars for 500 and 633 nm. c) Strehl ratio map of the same area. d) Surface figure assumptions for the four telescope optical elements---Primary Mirror (PM), Secondary Mirror (SM), Tertiary Mirror (TM), and FSM, showing the RMS wavefront and number of spatial frequencies (sp.fr.). The contribution of each of the four optics are multiplicatively combined to form the wavefront map, linear PSF, and log-colorbar PSF shown in e), f) and g). The circle, square, and star in c) indicate the field points which are shown in e), f) and g).
• Figure 3: a) Overview of the WCC focal plane showing the distribution of the sensors on the focal plane. Sony IMX sensors are shown in turquoise, and HWK qCMOS sensors are shown in purple. The grey boxes indicate the detector control board footprints. The entrance apertures to the IFS and ESC instruments are also indicated with the red circles. Filter locations are subject to change pending instrument design optimization. b) Overview of the WCC filter suite as a function of wavelength. The nominal quantum efficiency of the Sony IMX 455 and the HWK 4123 qCMOS sensors are shown as solid black and dot-dashed green lines, respectively.
• Figure 4: Expected photometric precision (black curve; left axis) in ppm and S/N (right axis) as a function of stellar magnitude as observed in the in-focus WCC $r$ filter with the WCC in a 1 h effective exposure. The contributions from different noise sources are highlighted: photon noise (red), sky-background (purple), read noise (turquoise), and systematic noise floor (grey horizontal dashed line).
• Figure 5: a) Overview of the optical design of the Lazuli Integral Field Spectrograph, showing the injection optics, integral field unit (IFU), collimator, prism, the camera subsystem, and the detector module subsystem. b) The input fields of view of the IFS, which is composed of a 2.3$\times$4.6 Narrow Field (NF), and a 4.6$\times$8.8 Wide Field (WF). c) Overview of the expected locations of the 116 traces (58 per subfield) as viewed on the $4096 \times 4096$ pixels of the H4RG-10 detector. The overview of the slices is generated by the slicersim code (Rigault et al. 2026, in prep.).