The Colorado Ultraviolet Transit Experiment (CUTE) is a 6U CubeSat designed to explore the upper atmospheres of short-period exoplanets via near-ultraviolet (2500 – 3300 Å) transmission spectroscopy, with an anticipated launch date of September 2021. The 4U science instrument comprises a Cassegrain telescope with a 20 × 8 cm primary mirror, a spectrograph, and a thermal-electrically cooled CCD detector. The spacecraft structure and a 1.5U XB1 avionics module are provided by Blue Canyon Technologies. CUTE’s novel and compact instrument design presents unique challenges to conducting component-level testing, alignment, instrument and spacecraft integration, calibration, and end-to-end performance testing. We provide a description of several custom test setups and procedures designed to characterize the spectrograph performance and its expected science return. We also outline the remainder of our integration and testing plan.
The SPRITE cubesat is a recently selected NASA astrophysics mission designed to measure ionizing radiation escape from star-forming galaxies, and to map far-ultraviolet (1000 - 1750 Å) emission from shocked regions in supernova remnants. The instrument leverages a number of new technologies identified for future large mission concepts, including the LUVOIR surveyor, to achieve the required performance. These include high broadband reflectivity mirror coatings and an ultra-low background photon counting microchannel plate detector with an anti-coincidence particle rejection system. SPRITE will serve as a flight testbed for these technologies, employing a robust calibration program as part of the principal science mission to advance the technology readiness level (TRL) to 7+ and provide heritage for future Explorer-class and larger missions. SPRITE is a 6U class cubesat funded through NASA ROSES with an anticipated launch date in 2022. The science data products will be archived on the Mikulski Archive for Space Telescopes (MAST). This proceedings describes the instrument science program, optical design, preliminary performance projections, and project timeline.
In this proceeding, we describe the scientific motivation and technical development of the Colorado Highresolution Echelle Stellar Spectrograph (CHESS), focusing on the hardware advancements and testing of components for the fourth and final launch of the payload (CHESS-4). CHESS is a far ultraviolet rocket-borne instrument designed to study the atomic-to-molecular transitions within translucent cloud regions in the interstellar medium. CHESS is an objective echelle spectrograph, which uses a mechanically-ruled echelle and a powered (f/12.4) cross-dispersing grating; it is designed to achieve a resolving power R > 100,000 over the band pass λλ 1000–1600 Å. CHESS-4 utilizes a 40 mm-diameter cross-strip anode readout microchannel plate detector, fabricated by Sensor Sciences LLC, to achieve high spatial resolution with high global count rate capabilities (∼ MHz). An error in the fabrication of the cross disperser limited the achievable resolution on previous launches of the payload to R ∼ 4000. To remedy this for CHESS-4, we physically stress the echelle grating, introducing a shallow toroidal curvature to the surface of the optic. Preliminary laboratory measurements of the resulting spectrum show a factor of 4–5 improvement to the resolving power. Results from final efficiency and reflectivity measurements for the optical components of CHESS-4 are presented, along with the pre-flight laboratory spectra and calibration results. CHESS-4 launched on 17 April 2018 aboard NASA/University of Colorado Boulder sounding rocket mission 36.333 UG. We present flight results for the observation of the γ Ara sightline.
The Colorado Ultraviolet Transit Experiment (CUTE) is a near-UV (NUV), 6U CubeSat designed to characterize the interaction between exoplanetary atmospheres and their host stars. CUTE is dedicated to observing multiple transits of short period planets with a range of masses to measure the transit depths of atomic and molecular nearUV features. These observations will enable us to quantify as a function of wavelength the transit ingress, egress, and depth of exoplanet light curves in order to determine the presence of bow shocks and strong atmospheric mass loss. The CUTE optical system combines a novel rectangular Cassegrain telescope and a holographically-ruled, aberration-correcting diffraction grating. The high-throughput optical system is projected to obtain an average effective area of ≈24 cm2 , comparable to previous Explorer class missions (GALEX) in a CubeSat package. This proceeding provides an overview of the science motivation, the final telescope and spacecraft design, and an outline of the mission operation.
In this proceeding, we describe the scientific motivation and technical development of the Colorado HighResolution Echelle Stellar Spectrograph (CHESS), focusing on the hardware advancements and testing of components for the third launch of the payload (CHESS-3). CHESS is a far ultraviolet rocket-borne instrument designed to study the atomic-to-molecular transitions within translucent cloud regions in the interstellar medium. CHESS is an objective echelle spectrograph, which uses a mechanically-ruled echelle and a powered (f/12.4) crossdispersing grating, and is designed to achieve a resolving power R > 100,000 over the bandpass λλ 1000−1600 Å. Results from final efficiency and reflectivity measurements for the optical components of CHESS-3 are presented. An important role of sounding rocket experiments is the testing and verification of the space flight capabilities of experimental technologies. CHESS-3 utilizes a 40mm-diameter cross-strip anode microchannel plate detector fabricated by Sensor Sciences LLC, capable of achieving high spatial resolution and a high global count rate (∼1 MHz). We present pre-flight laboratory spectra and calibration results, including wavelength solution and resolving power of the instrument. The fourth launch of CHESS (CHESS-4) will demonstrate a δ-doped CCD, assembled in collaboration with the Microdevices Laboratory at JPL and Arizona State University. In support of CHESS-4, the CHESS-3 payload included a photomultiplier tube, used as a secondary confirmation of the optical alignment of the payload during flight. CHESS-3 launched on 26 June 2017 aboard NASA/CU sounding rocket mission 36.323 UG. We present initial flight results for the CHESS-3 observation of the β1 Scorpii sightline.