The distribution of satellite galaxies about isolated host galaxies in the second data release of the Sloan Digital Sky Survey (SDSS) is investigated. Host–satellite systems are selected using three different methods, yielding samples of ∼ 2100 satellites, ∼ 1300 satellites, and ∼ 650 satellites. All three samples of satellites show highly significant deviations from isotropy relative to the ma...

We have surveyed the Hill sphere of Mars for irregular satellites. Our search covered nearly the entire Hill sphere, but scattered light from Mars excluded the inner few arcminutes where the satellites Phobos and Deimos reside. No new satellites were found to an apparent limiting red magnitude of 23.5, which corresponds to radii of about 0.09 km using an albedo of 0.07.

A fractionated spacecraft is a system comprising of a cluster of wirelessly communicating satellites, each with sensors, embedded processors, data storage, attitude control and propulsion. These clusters have several advantages over monolithic satellites: they offer redundancy, the economy of smaller satellites and resource sharing. However, there are other challenges beyond those of distribute...

The introduction of AIS will change maritime surveillance in the future. We explore how satellites can complement or extend this cooperative surveillance technique. Radar satellites alone are not sufficient. Micro-satellites carrying sensors for reception of navigation radar pulses or AIS signals offer some promising options.

Using high-resolution cosmological hydrodynamical simulations of Milky Way-massed disk galaxies, we demonstrate that supernovae feedback and tidal stripping lower the central masses of bright (−15 < MV < −8) satellite galaxies. These simulations resolve high-density regions, comparable to giant molecular clouds, where stars form. This resolution allows us to adopt a prescription for H2 formatio...

Recently, Formation Flying of satellites has been recognized as an important future on-orbit technology. It has much potential such as leading to flexibility of space mission, low cost, etc. However, conventional thrusters consume propellant fuel, which leads to high cost, high weight and restricted mission life-time. Consequently, magnetic force, which doesn’t consume fuel, is widely focused t...

Mutant knots, in the sense of Conway, are known to share the same Homfly polynomial. Their 2-string satellites also share the same Homfly polynomial, but in general their m-string satellites can have different Homfly polynomials for m > 2. We show that, under conditions of extra symmetry on the constituent 2-tangles, the directed m-string satellites of mutants share the same Homfly polynomial f...

We have been conducting spectroscopic observations of satellites in addition to photometric observations since last summer at the Kyung-Hee Optical Satellite Observation and Tracking Facility (KOSOTF). We began with observing slowly moving objects, such as geo-stationary satellites. We have undergone many trials and errors to succeed in the spectroscopic observations of these satellites. Necess...

NASA's Galileo mission to Jupiter and improved Earth-based observing capabilities have allowed major advances in our understanding of Jupiter's moons Io, Europa, Ganymede, and Callisto over the past few years. Particularly exciting findings include the evidence for internal liquid water oceans in Callisto and Europa, detection of a strong intrinsic magnetic field within Ganymede, discovery of h...