Lynx is a concept under study for prioritization in the 2020 Astrophysics Decadal Survey. Providing orders of magnitude increase in sensitivity over Chandra, Lynx will examine the first black holes and their galaxies, map the large-scale structure and galactic halos, and shed new light on the environments of young stars and their planetary systems. In order to meet the Lynx science goals, the telescope consists of a high-angular resolution optical assembly complemented by an instrument suite that may include a High Definition X-ray Imager, X-ray Microcalorimeter and an X-ray Grating Spectrometer. The telescope is integrated onto the spacecraft to form a comprehensive observatory concept. Progress on the formulation of the Lynx telescope and observatory configuration is reported in this paper.

This paper discusses the importance of fusion propulsion for interplanetary space travel, illustrates why the magnetoinertial fusion parameter space may facilitate the most rapid, economic path for development, justifies the choice of pulsed Z pinch, and provides a potential development path leading up to a technical readiness level 9 system. Round trips of less than one year to Mars are only possible using fusion propulsion systems. Such a system will require an onboard nuclear fission reactor for reliable startups, and so fission and fusion developments for space are mutually beneficial. The paper reviews the more than 50 year history of fusion research and summarizes results from a recent study of the fusion parameter space for terrestrial power, which suggests magnetoinertial fusion can provide the smallest, most economical approach for a fusion propulsion system. Emerging experimental data and theory show pulsed Z-pinch fusion solves some of the most deleterious instabilities and scales to fusion breakeven within reach of current pulsed power facilities. The paper illustrates a potential development path to a technical readiness level 9 flight system, starting from an assumed technical readiness level 2 for the current state of fusion propulsion. Nomenclature a = acceleration, m∕s 2 g 0 = gravitational acceleration at Earth's surface, m∕s 2 J = mission difficulty parameter, m 2 ∕s 3 k = ratio of tank to propellant mass m = mass, kg _ m = mass flow rate, kg∕s N = total number of stages, number of fusion reactions n = number density P = power, W R = distance traveled, m T = total trip time and time, s t = time, s V = reacting volume, m 3 v j = jet or exhaust velocity, m∕s Y = fusion energy yield, J α = propulsion system specific mass, kg∕W β = mission type multiplication factor γ = ratio of propulsion system to initial mass of nth stage Δv = velocity increment, m∕s λ = payload mass fraction τ = characteristic time, s Subscripts burn = propulsive burn c, coast = unpowered coasting conf = confinement d = dwell, as in dwell time τ d f = final fus = fusion jet = jet, as in for jet power P jet n = number of the stage opt = optimum p = propulsion time pay = payload pn = propulsion time for nth stage (as in for T pn ) pr = propellant ps = propulsion system t = tank 0 = initial 1, 2 = dummy subscripts indicating different species

Z-pinch and Dense Plasma Focus (DPF) are two promising techniques for bringing fusion power to the field of in-space propulsion. A design team comprising of engineers and scientists from UAHuntsville, NASA's George C. Marshall Space Flight Center and the University of Wisconsin developed concept vehicles for a crewed round trip mission to Mars and an interstellar precursor mission. Outlined in this paper are vehicle concepts, complete with conceptual analysis of the mission profile, operations, structural and thermal analysis and power/avionics design. Additionally engineering design of the thruster itself is included. The design efforts adds greatly to the fidelity of estimates for power density (alpha) and overall performance for these thruster concepts.

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The Advanced X-ray Timing Array (AXTAR) is a mission concept for X-ray timing of compact objects that combines very large collecting area, broadband spectral coverage, high time resolution, highly flexible scheduling, and an ability to respond promptly to time-critical targets of opportunity. It is optimized for submillisecond timing of bright Galactic X-ray sources in order to study phenomena at the natural time scales of neutron star surfaces and black hole event horizons, thus probing the physics of ultradense matter, strongly curved spacetimes, and intense magnetic fields. AXTAR's main instrument, the Large Area Timing Array (LATA) is a collimated instrument with 2-50 keV coverage and over 3 square meters effective area. The LATA is made up of an array of supermodules that house 2-mm thick silicon pixel detectors. AXTAR will provide a significant improvement in effective area (a factor of 7 at 4 keV and a factor of 36 at 30 keV) over the RXTE PCA. AXTAR will also carry a sensitive Sky Monitor (SM) that acts as a trigger for pointed observations of X-ray transients in addition to providing high duty cycle monitoring of the X-ray sky. We review the science goals and technical concept for AXTAR and present results from a preliminary mission design study.

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In September 2013 the NASA Innovative Advanced Concept (NIAC) organization awarded a phase I contract to the PuFF team. Our phase 1 proposal researched a pulsed fission-fusion propulsion system that compressed a target of deuterium (D) and tritium (T) as a mixture in a column, surrounded concentrically by Uranium. The target is surrounded by liquid lithium. A high power current would flow down the liquid lithium and the resulting Lorentz force would compress the column by roughly a factor of 10. The compressed column would reach criticality and a combination of fission and fusion reactions would occur. Our Phase I results, summarized herein, review our estimates of engine and vehicle performance, our work to date to model the fission-fusion reaction, and our initial efforts in experimental analysis. NomenclatureA = Target Surface Area B = Magnetic Field pressure E = Electric Field f = fractional deposition of alpha particles h = smoothing length H = Magnetic Field J = current density k = thermal conductivity, Boltzmann's constant m = mass n = number density P = Pressure Q = fusion reaction energy Qi = thermal equilibrium term r = position Re = friction tensor 1 Aerospace Engineer, ER24/Advanced Propulsion and Technology, Associate Fellow. 2 t = time T = Temperature u = velocity V = Volume W = kernel Z = ion charge  = permittivity  = conductivity  = viscous stress tensor  = magnetic permeability  = density <> = velocity averaged fusion cross section