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Do employees at public colleges and universities have better retirement benefits than K-12 employees? This is the central question in the new report "Choice and Quality Among Retirement Plans for Educators." To answer this question, we evaluate the quality of higher education and K-12 retirement plans using five key variables: (1) Choice: Do employees have a choice over their retirement plan?; (2) Vesting: How long do employees have to stay in the system to qualify for employer-provided retirement benefits?; (3) Benefits: What is the value of the benefit that employees receive from their employers?; (4) Debt: Has the plan built up unfunded obligations, and how much are employers contributing toward those unfunded liabilities?; and (5) Social Security: Are employees covered by Social Security? The analysis shows that K-12 teachers are often offered different, worse retirement benefits than those offered to public higher education employees. When compared with higher education employees, K-12 teachers are less likely to have choice over their retirement benefits, they have to serve longer to qualify for those benefits, and the benefits are worth less. Moreover, the K-12 sector is more burdened by unfunded liabilities, whereas higher education retirement plans are able to direct a higher share of employer contributions straight toward employee benefits. Based on these findings, the authors recommend that states provide the same retirement plan options for all public sector employees. K-12 teachers should have the same choices in their retirement plans as their higher education counterparts. Beyond expanding the number of retirement options, states need to ensure that the options they offer are good ones, including short vesting periods, portability, and adequate employer contributions. Adopting these recommendations will give K-12 employees access to more and better retirement options.

In recent years, a new movement to raise awareness about early math learning has been growing in the U.S., driven by research showing that foundational math knowledge is more predictive of later success in school than nearly any other indicator, including literacy. This awareness of the importance of early math has led to an increasing focus among funders, researchers, and educators on understanding how to effectively promote development of math skills in early childhood -- both in educational settings and in the home. Any effort to improve opportunity gaps in U.S. education must include attention to the needs of dual language learners (DLLs), defined as young children between the ages of 0 and 8 with at least one parent who speaks a language other than English at home. Many DLLs are faced with socioeconomic opportunity gaps and an education system designed for monolingual students. These factors likely contribute to the disparities in early math achievement for DLLs that are evident as early as kindergarten and persist throughout the academic career and beyond. This report sets out to begin addressing the gap in knowledge about effective strategies to promote early math learning for DLLs in educational settings and at home. The report begins with an overview of the importance of early math learning, followed by an overview of math achievement among DLLs nationally and in California. Next, the authors examine existing evidence about effective and promising practices for supporting DLLs' early math learning in school and for engaging DLL families in early math at home, including profiles of two organizations that embody the lessons they identify for supporting DLLs' early math achievement. The following section highlights research, policy, and practice gaps and opportunities related to promoting early math for DLLs. Finally, the authors offer recommendations for opportunities for improving support for DLLs' early math achievement in research, policy, and practice.

School performance frameworks (SPFs) are action-oriented information tools that provide information on school performance and quality across a variety of measures. SPFs have evolved as a solution for local communities to make sense of an array of student, school, and system performance data, and to support transparent and equitable decisions. SPFs can be especially useful to communities grappling with various autonomous public school structures, school accountability systems, broader school choice, and ambitious school improvement goals. The report examines how local education leaders can create, implement, and sustain effective SPFs. The report details established, locally focused SPFs in New York City, Chicago, Denver, New Orleans, and Washington, D.C., and draws on research and interviews with SPF experts across the country. It also includes an SPF planning guide for education leaders at the local and state level who are beginning to design an SPF, considering an SPF redesign, or implementing an existing SPF.

Although annual state tests had been federally required since 2001, and the consortia and standards were led by states, the new tests became a focal point of narratives about federal overreach and over-testing. Current wisdom holds that testing has become politically toxic. There are real risks that some states are rolling back advancements in test quality, accessibility, and rigor in the name of reducing test time and cost, or answering political pressures. States are continuing to rethink their roles in assessment and their assessment systems in ways that may benefit teaching, learning, transparency, and equity. This brief highlights developing trends and opportunities for state systems of assessment, especially in areas beyond federally mandated reading and math assessments. Which states are pursuing these ideas, and what might be holding others back? What are the risks and rewards of investment and innovation in new test designs or assessments? In particular the brief discusses the landscape of: (1) Interim assessments for accountability; (2) Formative assessments to support instruction; (3) Interstate collaborations and shared item banks; and (4) Science and social studies assessments. Although these four topics do not represent the totality of progress and innovation in assessment, these four were chosen because they are each examples where innovation and improvement is within close reach for states, and where some states are already leading in ways that may be instructive.

CUBESATS are relatively new spacecraft platforms that are typically deployed from a launch vehicle as a secondary payload,1 providing low-cost access to space for a wide range of end-users. These satellites are comprised of building blocks having dimensions of 10x10x10 cm cu and a mass of 1.33 kg (a 1-U size). While providing low-cost access to space, a major operational limitation is the lack of a propulsion system that can fit within a CubeSat and is capable of executing high delta v maneuvers. This makes it difficult to use CubeSats on missions requiring certain types of maneuvers (i.e. formation flying, spacecraft rendezvous). Recently, work has been performed investigating the use of iodine as a propellant for Hall-effect thrusters (HETs) 2 that could subsequently be used to provide a high specific impulse path to CubeSat propulsion. Iodine stores as a dense solid at very low pressures, making it acceptable as a propellant on a secondary payload. It has exceptionally high ρIsp (density times specific impulse), making it an enabling technology for small satellite near-term applications and providing the potential for systems-level advantages over mid-term high power electric propulsion options. Iodine flow can also be thermally regulated, subliming at relatively low temperature ( less than100 C) to yield I2 vapor at or below 50 torr. At low power, the measured performance of an iodine-fed HET is very similar to that of a state-of-the-art xenon-fed thruster. Just as importantly, the current-voltage discharge characteristics of low power iodine-fed and xenon-fed thrusters are remarkably similar, potentially reducing development and qualifications costs by making it possible to use an already-qualified xenon-HET PPU in an iodine-fed system. Finally, a cold surface can be installed in a vacuum test chamber on which expended iodine propellant can deposit. In addition, the temperature doesn't have to be extremely cold to maintain a low vapor pressure in the vacuum chamber (it is under 10(exp -6) torr at -75 C), making it possible to 'cryopump' the propellant with lower-cost recirculating refrigerant-based systems as opposed to using liquid nitrogen or low temperature gaseous helium cryopanels. In the present paper, we describe testing performed using an iodine-fed 200 W Hall thruster mounted to a thrust stand and operated in conjunction with MSFCs Small Projects Rapid Integration and Test Environment (SPRITE) Portable Hardware In the Loop (PHIL) hardware. This work is performed in support of the iodine satellite (iSAT) project, which aims to fly a 200-W iodine-fed thruster on a 12-U CubeSat. The SPRITE PHIL hardware allows a given vehicle to do a checkout of its avionics algorithm by allowing it to monitor and feed data to simulated sensors and effectors in a digital environment. These data are then used to determine the attitude of the vehicle and a separate computer is used to interpret the data set and visualize it using a 3D graphical interface. The PHIL hardware allows the testing of the vehicles bus by providing 'real' hardware interfaces (in the case of this test a real RS422 bus) and specific components can be modeled to show their interactions with the avionics algorithm (e.g. a thruster model). For the iSAT project the PHIL is used to visualize the operating cycle of the thruster and the subsequent effect this thrusting has on the attitude of the satellite over a given period of time. The test is controlled using software running on an Andrews Space Cortex 160 flight computer. This computer is the current baseline for a full iSAT mission. While the test could be conducted with a lab computer and software, the team chose to exercise the propulsion system with a representative CubeSat-class computer. For purposes of this test, the "flight" software monitored the propulsion and PPU systems, controlled operation of the thruster, and provided thruster state data to the PHIL simulation. Commands to operate the thruster were initiated from an operator's workstation outside the vacuum chamber and passed through the Cortex 160 to exercise portions of the flight avionics. Two custom-designed pieces of electronics hardware have been designed to operate the propellant feed system. One piece of hardware is an auxiliary board that controls a latch valve, proportional flow control valves (PFCVs) and valve heaters as well as measuring pressures, temperatures and PFCV feedback voltage. An onboard FPGA provides a serial link for issuing commands and manages all lower level input-output functions. The other piece of hardware is a power distribution board, which accepts a standard bus voltage input and converts this voltage into all the different current-voltage types required to operate the auxiliary board. These electronics boards are located in the vacuum chamber near the thruster, exposing this hardware to both the vacuum and plasma environments they would encounter during a mission, with these components communicating to the flight computer through an RS-422 interface. The auxiliary board FPGA provides a 28V MOSFET switch circuit with a 20ms pulse to open or close the iodine propellant feed system latch valve. The FPGA provides a pulse width modulation (PWM) signal to a DC/DC boost converter to produce the 12-120V needed for control of the proportional flow control valve. There are eight MOSFET-switched heating circuits in the system. Heaters are 28V and located in the latch valve, PFCV, propellant tank and propellant feed lines. Both the latch valve and PFCV have thermistors built into them for temperature monitoring. There are also seven resistance temperature device (RTD) circuits on the auxiliary board that can be used to measure the propellant tank and feedline temperatures. The signals are conditioned and sent to an analog to digital converter (ADC), which is directly commanded and controlled by the FPGA.

The development and testing of a 200-W iodine-fed Hall thruster propulsion system that will be flown on a 12-U CubeSat is described. The switch in propellant from more traditional xenon gas to solid iodine yields the advantage of high density, low pressure propellant storage but introduces new requirements that must be addressed in the design and operation of the propulsion system. The thruster materials have been modified from a previously-flown xenon Hall thruster to make it compatible with iodine vapor. The cathode incorporated into this design additionally requires little or no heating to initiate the discharge, reducing the power needed to start the thruster. The feed system produces iodine vapor in the propellant reservoir through sublimation and then controls the flow to the anode and cathode of the thruster using a pair of proportional flow control valves. The propellant feeding process is controlled by the power processing unit, with feedback control on the anode flow rate provided through a measure of the thruster discharge current. Thermal modeling indicates that it may be difficult to sufficiently heat the iodine if it loses contact with the propellant reservoir walls, serving to motivate future testing of that scenario to verify the modeling result and develop potential mitigation strategies. Preliminary, short-duration materials testing has thus-far indicated that several materials may be acceptable for prolonged contact with iodine vapor, motivating longer-duration testing. A propellant loading procedure is presented that aims to minimize the contaminants in the feed system and propellant reservoir. Finally, an 80-hour duration test being performed to gain experience operating the thruster over long durations and multiple restarts is discussed.