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 that will collect and return data from Pluto in 2015. 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 needed to reach the Pluto system prior to the year 2020. The spacecraft subsystems were designed to meet tight mass and power allocations, yet provide the necessary control and data handling finesse to support data collection and return when the one-way light time during the Pluto flyby is 4.5 hours. Missions to the outer solar system require a radioisotope thermoelectric generator (RTG) to supply electrical power, and a single RTG is used by New Horizons. To accommodate this constraint, the spacecraft electronics were designed to operate on less than 200 W. The spacecraft system architecture provides sufficient redundancy to provide a probability of mission success of greater than 0.85, even with a mission duration of over 10 years. The spacecraft is now on its way to Pluto, with an arrival date of 14 July 2015. Initial inflight tests have verified that the spacecraft will meet the design requirements.Comment: 33 pages, 13 figures, 4 tables; To appear in a special volume of Space Science Reviews on the New Horizons missio

Correlation and Taylor scale variability in the interplanetary magnetic field fluctuations as a function of solar wind speed

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95101/1/jgra21350.pd

Achievements and Challenges in the Science of Space Weather

In June 2016 a group of 40 space weather scientists attended the workshop on Scientific Foundations of Space Weather at the International Space Science Institute in Bern. In this lead article to the volume based on the talks and discussions during the workshop we review some of main past achievements in the field and outline some of the challenges that the science of space weather is facing today and in the future.Peer reviewe

High-Resolution Measurements of the Cross-Shock Potential, Ion Reflection, and Electron Heating at an Interplanetary Shock by MMS

International audienceThe Magnetospheric Multiscale (MMS) spacecraft obtained unprecedented high-time resolution multipoint particle and field measurements of an interplanetary shock event on 8 January 2018. The spacecraft encountered the supercritical forward shock of a forward/reverse shock pair in the pristine solar wind upstream of the bow shock near the subsolar point as they neared apogee at 25 RE. The high-time resolution measurements from the four spacecraft, separated by only 20 km, allowed direct measurement of particle distributions revealing evidence of electron heating and near specularly reflected ions. The cross-shock potential is calculated directly from 3-D electric field measurements. This is the first reported direct high temporal resolution (<1 s) observation at an interplanetary shock of near specularly reflected ions. Calculation of the cross-shock potential yields a potential jump significant enough to reflect at least some of the protons from the incident solar wind beam. The cross-shock potential calculated here is consistent with previous estimations based on particle measurements and numerical/analytical simulations. The ambipolar contribution to the cross-shock potential calculated from the four-spacecraft divergence of the electron pressure tensor is somewhat higher than that inferred form the Liouville-mapped electron energy gain across the shock. Furthermore, the high-time-resolution 3-D electric field measurements reported here reveal small-scale nonlinear structures embedded in the shock layer that contribute to the nonmonotonic shock transition