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Although most brain-machine interface (BMI) studies have focused on decoding kinematic parameters of motion such as hand position and velocity, it is known that motor cortical activity also correlates with kinetic signals, including active hand force and joint torque. Here, we attempted to reconstruct torque trajectories of the shoulder and elbow joints from the activity of simultaneously recorded units in primary motor cortex (MI) as monkeys (Macaca Mulatta) made reaching movements in the horizontal plane. Using a linear filter decoding approach that considers the history of neuronal activity up to one second in the past, we found torque reconstruction performance nearly equal to that of Cartesian hand position and velocity, despite the considerably greater bandwidth of the torque signals. Moreover, the addition of delayed position and velocity feedback to the torque decoder substantially improved the torque reconstructions, suggesting that simple limb-state feedback may be useful to optimize BMI performance. These results may be relevant for BMI applications that require controlling devices with inherent, physical dynamics or applying forces to the environment.

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The citizen Continental-America Telescopic Eclipse (CATE) Experiment was a new type of citizen science experiment designed to capture a time sequence of white-light coronal observations during totality from 17:16 to 18:48 UT on 2017 August 21. Using identical instruments the CATE group imaged the inner corona from 1 to 2.1 RSun with 1.″43 pixels at a cadence of 2.1 s. A slow coronal mass ejection (CME) started on the SW limb of the Sun before the total eclipse began. An analysis of CATE data from 17:22 to 17:39 UT maps the spatial distribution of coronal flow velocities from about 1.2 to 2.1 RSun, and shows the CME material accelerates from about 0 to 200 km s−1 across this part of the corona. This CME is observed by LASCO C2 at 3.1–13 RSun with a constant speed of 254 km s−1. The CATE and LASCO observations are not fit by either constant acceleration nor spatially uniform velocity change, and so the CME acceleration mechanism must produce variable acceleration in this region of the corona.

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The major problem that orbital debris presents to a particular space structure is not that of catastrophic collision, which fragments the structure, but rather the threat of collisions with small debris that will damage it. In this paper, a method is developed for defining the debris environment to support the analysis of vulnerability of space structures. Flux directionality functions related to spacecraft surface degradation, which are seen to be various velocity moments of the phase space debris density distribution, are derived for both the man-made debris environment and for a simple model of the meteoroid environment. A method for accounting for the shielding of spacecraft surfaces by other spacecraft components is also presented within the flux directionality context. Nomenclature= cos D k = fcth cumulative mass moment of 3D 3D = differential size distribution dQ = differential element of solid angle $ = number flux density, impacts/km 2 /s/sr 5^ = crater area flux density, cm 2 /km 2 /s/sr $ e = kinetic energy flux density, erg/km 2 /s/sr 3m = cumulative mass flux density, g/km 2 /s/sr voi = crater volume flux density, cm 3 /km 2 /s/sr h 0 = spacecraft altitude / = debris incidence angle (i.e., angle of debris impact relative to a spacecraft surface element) n = number density, /km 3 q = phase space mass density distribution R E = radius of Earth r = position S% =sin £ v = velocity, km/s v sc = spacecraft velocity in an Earth-centered inertial reference frame 7 = angle between spacecraft velocity vector and debris velocity vector in an Earth-centered inertial reference frame ?! = phase space number density, /kmVs 3 0 = yaw angle (angle in local horizontal plane) p = mass density, g/cm 3

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