The Space-based Telescopes for Actionable Refinement of Ephemeris (STARE) program will collect the information needed to help satellite operators avoid collisions in space by using a network of nanosatellites to determine more accurate trajectories for selected space objects orbiting the Earth. In the first phase of the STARE program, two pathfinder cube-satellites (CubeSats) equipped with an optical imaging payload are being developed and deployed to demonstrate the main elements of the STARE concept. We first give an overview of the STARE program. The details of the optical imaging payload for the STARE pathfinder CubeSats are then described, followed by a description of the track detection algorithm that will be used on the images it acquires. Finally, simulation results that highlight the effectiveness of the mission are presented.
The Space-based Telescopes for Actionable Refinement of Ephemeris (STARE) program will collect the information
needed to help satellite operators avoid collisions in space by using a network of nano-satellites to determine
more accurate trajectories for selected space objects orbiting the Earth. In the first phase of the STARE program,
two pathfinder cube-satellites (CubeSats) equipped with an optical imaging payload are being developed
and deployed to demonstrate the main elements of the STARE concept. In this paper, we first give an overview
of the STARE program. We then describe the details of the optical imaging payload for the STARE pathfinder
CubeSats, including the optical design and the sensor characterization. Finally, we discuss the track detection
algorithm that will be used on the images acquired by the payload.
Orbital collisions pose a hazard to space operations. Using a high performance computer modeling and simulation
environment for space situational awareness, we explore a new paradigm for improving satellite conjunction analysis by
obtaining more precise orbital information only for those objects that pose a collision risk greater than a defined
threshold to a specific set of satellites during a specified time interval. In particular, we assess the improvement in the
quality of the conjunction analysis that can be achieved using a distributed network of ground-based telescopes.
We report on observations of two quasar host galaxies made with the Lick Observatory adaptive optic system using a laser guide star tuned to the wavelength of the sodium D lines. A brief outline of the system is given, and a description of its performance when obtaining science data. We discuss techniques for obtaining calibration of the point spread function and the analysis steps required to obtain useful scientific results. We present <i>H</i>-band images of quasar host galaxies made with the system. Estimates of the host galaxy
magnitudes and central black hole masses were made from these data.
These are the first observations of quasar host galaxies with a sodium laser guide star.
High redshift radio galaxies are great cosmological tools for pinpointing the most massive objects in the early Universe: massive forming galaxies, active super-massive black holes and proto-clusters. We report on deep narrow-band imaging and spectroscopic observations of several <i>z</i> > 2 radio galaxy fields to investigate the nature of giant Ly-α nebulae centered on the galaxies and to search for over-dense regions around them. We discuss the possible implications for our understanding of the formation and evolution of massive galaxies and galaxy clusters.
The host galaxies of powerful radio sources are ideal laboratories to study active galactic nuclei (AGN). The galaxies themselves are among the most massive systems in the universe, and are believed to harbor supermassive black holes (SMBH). If large galaxies are formed in a hierarchical way by multiple merger events, radio galaxies at low redshift represent the end-products of this process. However, it is not clear why some of these massive ellipticals have associated radio emission, while others do not. Both are thought to contain SMBHs, with masses proportional to the total luminous mass in the bulge. It either implies every SMBH has recurrent radio-loud phases, and the radio-quiet galaxies happen to be in the "low" state, or that the radio galaxy nuclei are physically different from radio-quiet ones, i.e. by having a more massive SMBH for a given bulge mass.
Here we present the first results from our adaptive optics imaging and spectroscopy pilot program on three nearby powerful radio galaxies. Initiating a larger, more systematic AO survey of radio galaxies (preferentially with Laser Guide Star equipped AO systems) has the potential of furthering our understanding of the physical properties of radio sources, their triggering, and their subsequent evolution.