The Colorado Ultraviolet Transit Experiment Mission Overview

Abstract

Atmospheric escape is a fundamental process that affects the structure, composition, and evolution of many planets. The signatures of escape are detectable on close-in, gaseous exoplanets orbiting bright stars, owing to the high levels of extreme-ultraviolet irradiation from their parent stars. The Colorado Ultraviolet Transit Experiment (CUTE) is a CubeSat mission designed to take advantage of the near-ultraviolet stellar brightness distribution to conduct a survey of the extended atmospheres of nearby close-in planets. The CUTE payload is a magnifying near-ultraviolet (2479–3306 Å) spectrograph fed by a rectangular Cassegrain telescope (206 mm × 84 mm); the spectrogram is recorded on a back-illuminated, UV-enhanced CCD. The science payload is integrated into a 6U Blue Canyon Technology XB1 bus. CUTE was launched into a polar, low-Earth orbit on 2021 September 27 and has been conducting this transit spectroscopy survey following an on-orbit commissioning period. This paper presents the mission motivation, development path, and demonstrates the potential for small satellites to conduct this type of science by presenting initial on-orbit science observations. The primary science mission is being conducted in 2022–2023, with a publicly available data archive coming online in 2023.

CUTE Reveals Escaping Metals in the Upper Atmosphere of the Ultrahot Jupiter WASP-189b

“…Each transit (one CUTE visit) was observed over a period approximately 5 times the transit duration covering the planet's orbital phase from −0.2 to 0.2. A typical CUTE orbit is 96 minutes, and we observed the target for 16 orbits in visits 2 and 3, while in visit 1 the target has been observed for just 13 orbits due to observational constraints and a spacecraft reset (France et al 2023). The number of exposures per satellite orbit varies from one to five, depending on target position and pointing constraints that include the Sun angle, the Moon angle, the elevation cutoff with Earth's limb, the spacecraft settling time, and the location of the satellite with respect to the South Atlantic Anomaly (SAA) and polar keepout zones (Suresh et al 2023).…”

“…We present the analysis and results obtained from three NUV transit observations of WASP-189b collected with the Colorado Ultraviolet Transit Experiment (CUTE) mission, which is a NASA 6U CubeSat (with stowed dimensions of 11.0 × 23.7 × 36.2 cm) CubeSat carrying on board a rectangular Cassegrain telescope feeding light into a low-resolution NUV (2479-3306 Å) spectrograph (Fleming et al 2018;Egan et al 2023;France et al 2023). CUTE monitors transiting exoplanets orbiting bright stars to study the upper atmospheres and star-planet interaction processes.…”

Status and mission operations of the SPRITE 12U CubeSat: a probe of star formation feedback from stellar to galactic scales with far-UV imaging spectroscopy

“…The SPRITE rectangular Cassegrain telescope design is based on the design of the CUTE CubeSat telescope. 18 The rectangular parabolic primary mirror is designed to maximize the aperture area in the CubeSat rectangular form factor. The secondary mirror focuses an image on the slit.…”

Narrow Loophole for H2-Dominated Atmospheres on Habitable Rocky Planets around M Dwarfs

“…Meanwhile, temperate planets around M dwarfs receive intense high-energy irradiation from host stars because of their close-in orbits, and this intense irradiation can drive hydrodynamic escape from a H 2 -dominated atmosphere (e.g., Salz et al 2016;Kubyshkina et al 2018aKubyshkina et al , 2018b. The high-energy irradiation will be measured by a bevy of new spacecraft (Ardila et al 2022;France et al 2023). We are thus motivated to determine the lifetime of a moderate-sized H 2 atmospherepermitting surface liquid water-on a large rocky planet orbiting an M dwarf against the hydrodynamic escape and evaluate the geologic processes that could resupply the H 2 atmosphere.…”