An ultra stable optical bench for the magnetic survey satellite

An optical bench has been designed and built that must hold the alignment of five optical elements to deflections of 1–2 arc s during orbital operation. In addition, it must suffer no alignment changes during the launch and prestabilization phase of the mission. Severe weight constraints, in conjunction with the thermal and structural requirements, led to the choice of graphite fiber reinforced epoxy egg crate core and face sheets for the bench construction. Active temperature control was necessary to meet thermal deflection objectives, and novel kinematic mountings were required to prevent spacecraft bending from deflecting the bench. The structural and thermal analyses both show that the mission objectives can be met with margin by the present design. No adverse effects from launch are expected, and the maximum thermal bending is expected to be less than 2 arc s.     

The New Horizons Spacecraft

The New Horizons spacecraft was launched on 19 January 2006. The spacecraft was designed to provide a platform for seven instruments designated by the science team to collect and return data from Pluto in 2015. The design meets the requirements established by the National Aeronautics and Space Administration (NASA) Announcement of Opportunity AO-OSS-01. The design drew on heritage from previous missions developed at The Johns Hopkins University Applied Physics Laboratory (APL) and other missions such as Ulysses. The trajectory design imposed constraints on mass and structural strength to meet the high launch acceleration consistent with meeting the AO requirement of returning data prior to the year 2020. The spacecraft subsystems were designed to meet tight resource allocations (mass and power) yet provide the necessary control and data handling finesse to support data collection and return when the one-way light time during the Pluto fly-by is 4.5 hours. Missions to the outer regions of the solar system (where the solar irradiance is 1/1000 of the level near the Earth) require a radioisotope thermoelectric generator (RTG) to supply electrical power. One RTG was available for use by New Horizons. To accommodate this constraint, the spacecraft electronics were designed to operate on approximately 200 W. The travel time to Pluto put additional demands on system reliability. Only after a flight time of approximately 10 years would the desired data be collected and returned to Earth. This represents the longest flight duration prior to the return of primary science data for any mission by NASA. The spacecraft system architecture provides sufficient redundancy to meet this requirement with a probability of mission success of greater than 0.85. The spacecraft is now on its way to Pluto, with an arrival date of 14 July 2015. Initial in-flight tests have verified that the spacecraft will meet the design requirements.     

The Influence of Black Hole Binarity on Tidal Disruption Events

Space Science Reviews - Interstellar dust from the Local Interstellar Cloud was detected unambiguously for the first time in 1992 (Grün et al. in Nature 362:428–430,...