arXiv subjects

Marianna Dafčíková

Publications and source records attributed to Marianna Dafčíková.

4 recordsLinked to original sources

arXiv2026

The second Little UV Camera (LUVCam2) mission

The second Little UltraViolet Camera (LUVCam2) is a 80mm-diameter dual UV-optical space telescope that will observe the UV flares around low-mass stars, with planned flight as a $\sim$1.4U payload aboard the 3U CubeSat BRNOsat in late 2027. We present the concept of operations, full system architecture, optomechanical, and electrical design for LUVCam2. LUVCam2 is the second technology demonstration for the LUVCam electronics board, with the first LUVCam (LUVCam1) still operating in low-Earth orbit (launched July 2024). The main upgrade of LUVCam2 is the use of the backside-illuminated GSENSE4040BSI CMOS sensor, promising significant improvement to UV quantum efficiency over the frontside-illuminated model used in LUVCam1. Other upgrades to LUVCam2 include the incorporation of the LUVCam on-board computer onto the readout electronics, an integrated 1W heater and thermal control system, and novel operational capability for LUVCam2 to perform on-sensor star-tracking using optical images of background stars.

astro-ph.IM↗

arXiv2026

A report on the First Technology Demonstration mission of the Little UV Camera (LUVCam1)

Here we report on the status of the first on-orbit technology demonstration of the Little UV Camera (LUVCam1). LUVCam1 is a 0.4U payload aboard the 2U cubesat GRBBeta that was launched in July 2024. The primary objective of the mission was to qualify the GSENSE4040 CMOS sensor and its readout electronics in preparation for the Quick UltraVIolet Kilonova Surveyor (QUVIK; Werner et al. \cite{Werner22, Werner24}) satellite. LUVCam will serve as the primary scientific camera for this mission. We report on the performance of the GSENSE4040FSI sensor used on LUVCam1, beginning with its in-lab characterization followed by an assessment of its on-orbit performance using astronomical observations made by LUVCam1. The camera remains operational two years later and has taken pictures of the Moon and stars that we show here. Through LUVCam1, we demonstrated an approach leveraging new-space to qualify the latest COTS CMOS sensors for astronomy missions.

astro-ph.IM↗

arXiv2024

GRBAlpha and VZLUSAT-2: GRB observations with CubeSats after 3 years of operations

GRBAlpha is a 1U CubeSat launched in March 2021 to a sun-synchronous LEO at an altitude of 550 km to perform an in-orbit demonstration of a novel gamma-ray burst detector developed for CubeSats. VZLUSAT-2 followed ten months later in a similar orbit carrying as a secondary payload a pair of identical detectors as used on the first mission. These instruments detecting gamma-rays in the range of 30-900 keV consist of a 56 cm2 5 mm thin CsI(Tl) scintillator read-out by a row of multi-pixel photon counters (MPPC or SiPM). The scientific motivation is to detect gamma-ray bursts and other HE transient events and serve as a pathfinder for a larger constellation of nanosatellites that could localize these events via triangulation. At the beginning of July 2024, GRBAlpha detected 140 such transients, while VZLUSAT-2 had 83 positive detections, confirmed by larger GRB missions. Almost a hundred of them are identified as gamma-ray bursts, including extremely bright GRB 221009A and GRB 230307A, detected by both satellites. We were able to characterize the degradation of SiPMs in polar orbit and optimize the duty cycle of the detector system also by using SatNOGS radio network for downlink.

astro-ph.HE↗

arXiv2023

GRBAlpha: the smallest astrophysical space observatory -- Part 1: Detector design, system description and satellite operations

Aims. Since launched on 2021 March 22, the 1U-sized CubeSat GRBAlpha operates and collects scientific data on high-energy transients, making it the smallest astrophysical space observatory to date. GRBAlpha is an in-obit demonstration of a gamma-ray burst (GRB) detector concept suitably small to fit into a standard 1U volume. As it was demonstrated in a companion paper, GRBAlpha adds significant value to the scientific community with accurate characterization of bright GRBs, including the recent outstanding event of GRB 221009A. Methods. The GRB detector is a 75x75x5 mm CsI(Tl) scintillator wrapped in a reflective foil (ESR) read out by an array of SiPM detectors, multi-pixel photon counters by Hamamatsu, driven by two separate, redundant units. To further protect the scintillator block from sunlight and protect the SiPM detectors from particle radiation, we apply a multi-layer structure of Tedlar wrapping, anodized aluminium casing and a lead-alloy shielding on one edge of the assembly. The setup allows observations of gamma radiation within the energy range of 70-890 keV with an energy resolution of ~30%. Results. Here, we summarize the system design of the GRBAlpha mission, including the electronics and software components of the detector, some aspects of the platform as well as the current way of semi-autonomous operations. In addition, details are given about the raw data products and telemetry in order to encourage the community for expansion of the receiver network for our initiatives with GRBAlpha and related experiments.

astro-ph.IM↗