The LightSail 2 Solar Sailing Mission Summary

The LightSail 2 mission concluded a 3-year mission in November 2022, having successfully demonstrated controlled solar sailing in low-Earth orbit using a CubeSat platform. Flight data show that LightSail 2 successfully controlled its orientation relative to the Sun, with sustained periods of apogee raising and increasing orbital energy. The LightSail 2 solar sail was 5.6 m on a side and has a total deployed area of 32 m². Four independent triangular aluminized Mylar® sail sections 4.6 microns thick were Z-folded and stowed into four sail bays. The sail segments were deployed by four 4 m Triangular Retractable And Collapsible booms made of elgiloy. The booms were wound around a common spindle, with deployment driven by a Faulhaber motor containing Hall sensors. Attitude was controlled using a single-axis Sinclair Interplanetary momentum wheel and magnetic torque rods. During solar sailing operations, two 90 degree slews were performed each orbit to harness momentum from solar photons. The thrust from solar radiation pressure measurably reduced the rate of orbital decay, including an extended period of orbit raising. Two Planetary Society Cameras developed by the Aerospace Corporation were mounted at the tips of opposing solar panels, providing imaging for engineering evaluation and public engagement throughout mission operations. This paper provides a summary of the LightSail 2 mission implementation, including the flight system design and the pre-launch test program. LightSail 2 mission operations are described, including discussion of the ground system. Solar sailing performance is presented, and anomalies encountered during the mission are discussed. The Planetary Society\u27s decade-long LightSail program was entirely donor-funded, with over 50,000 contributors worldwide. With a total cost of about $7M for two flight missions, the LightSail program showed that solar sails can provide a cost-effective option for propulsion of CubeSat-class vehicles

The LightSail 2 Controlled Solar Sailing Demonstration Mission

The LightSail 2 mission is the culmination of a decade-long program sponsored by The Planetary Society to advance solar sailing technology. The objective of LightSail 2 is to demonstrate controlled solar sailing in Earth orbit using a CubeSat platform. The LightSail 2 attitude is controlled using a single-axis momentum wheel and magnetic torque rods. During solar sailing operations, two 90 degree slews are performed each orbit to harness momentum from solar photons. Flight data show that LightSail 2 is successfully controlling its orientation relative to the Sun, and the controlled thrust from solar radiation pressure is measurably reducing the rate of orbital decay. The Planetary Society declared LightSail 2 mission success on July 31, 2019. This paper provides an overview of the LightSail 2 mission implementation, including the design of the flight system and flight software, and the pre-launch testing program. A summary of LightSail 2 mission operations is provided, including a description of the ground system. Solar sailing performance is presented, and anomalies encountered during the mission are discussed. The flight team continues to refine solar sailing performance and conduct on-orbit imaging for engineering purposes and to engage public interest. The LightSail program is entirely donor-funded, with over 50,000 contributors around the globe

Revitalizing the South End - The Gateway for Downtown Springfield

This studio report explores a service learning strategy in the context of the Graduate Urban Design Studio taught in the Department of Landscape Architecture and Regional Planning at the University of Massachusetts Amherst. The primary goal of this project is to design the South End as the future gateway for downtown Springfield that will help to transform it into a vibrant urban community. Green design strategies, improvement of services and businesses for residents and the employees of local businesses, and new housing opportunities will enhance the vibrancy, resilience, and quality of life of this disadvantaged urban community. Revitalizing the South End - The Gateway for Downtown Springfield proposes improved parks, boulevards and Main Street as a mixed-use spine that will improve the neighborhood in a physical, cultural, and social sense. Six sustainable learning and planning principles have emerged from this studio: 1. Green infrastructure - Green streets as networks and structural framework 2. Sustainable urban form – Mixed use and pedestrian friendly neighborhoods 3. Community-building art - Expression of place and peopl

Town of Ludlow Master Plan. Part I: Envisioning 2030

The Master Plan Committee for the town of Ludlow contracted with the Pioneer Valley Planning Commission (PVPC) to prepare a new Master Plan. PVPC engaged the Department of Landscape Architecture and Regional Planning (LARP) at the University of Massachusetts Amherst to assist with a portion of the Master Plan work. This work included: executing analysis and assessment of existing community conditions, conducting a weekend visioning workshop, and developing land use scenarios for the purpose of providing concrete visualization of possible futures for the Town of Ludlow in 2030

Joint kinematics following bi-compartmental knee replacement during daily life motor tasks

In many cases knee osteoarthritis leads to total knee replacement surgery (TKR) even if the lateral compartment is not involved. More recently, a bicompartmental knee replacement system (BKR) (Journey Deuce, Smith & Nephew Inc., Memphis, TN, USA) has been developed that only replaces the medial tibiofemoral and the patellofemoral compartments, thus preserving both cruciate ligaments with its associated benefits. However information on the effect of BKR on in vivo knee joint kinematics is not widely available in the literature. Therefore, this study analyzed full three-dimensional knee joint kinematics in 10 postoperative BKR-subjects for a broad spectrum of relevant daily life activities: walking, walking followed by a cross-over or sidestep turn, step ascent and descent, mild squatting and chair rise. We analyzed to what extent normal knee motion is regained through comparison with their non-involved limb as well as a group of matched controls. Furthermore, coefficients of multiple correlation were calculated to assess the consistency of knee joint kinematics both within and between subject groups. This analysis demonstrated that, despite the presence of differences indicative for retention of pre-operative motion patterns and/or remaining compensations, knee joint kinematics in BKR limbs replicate, for a large range of daily-life motor tasks, the kinematics of the contra-lateral non-affected limbs and healthy controls to a similar extent as they are replicated within both these control groups

Variability in temperature-related mortality projections under climate change.

BackgroundMost studies that have assessed impacts on mortality of future temperature increases have relied on a small number of simulations and have not addressed the variability and sources of uncertainty in their mortality projections.ObjectivesWe assessed the variability of temperature projections and dependent future mortality distributions, using a large panel of temperature simulations based on different climate models and emission scenarios.MethodsWe used historical data from 1990 through 2007 for Montreal, Quebec, Canada, and Poisson regression models to estimate relative risks (RR) for daily nonaccidental mortality in association with three different daily temperature metrics (mean, minimum, and maximum temperature) during June through August. To estimate future numbers of deaths attributable to ambient temperatures and the uncertainty of the estimates, we used 32 different simulations of daily temperatures for June-August 2020-2037 derived from three global climate models (GCMs) and a Canadian regional climate model with three sets of RRs (one based on the observed historical data, and two on bootstrap samples that generated the 95% CI of the attributable number (AN) of deaths). We then used analysis of covariance to evaluate the influence of the simulation, the projected year, and the sets of RRs used to derive the attributable numbers of deaths.ResultsWe found that < 1% of the variability in the distributions of simulated temperature for June-August of 2020-2037 was explained by differences among the simulations. Estimated ANs for 2020-2037 ranged from 34 to 174 per summer (i.e., June-August). Most of the variability in mortality projections (38%) was related to the temperature-mortality RR used to estimate the ANs.ConclusionsThe choice of the RR estimate for the association between temperature and mortality may be important to reduce uncertainty in mortality projections

Variability in Temperature-Related Mortality Projections under Climate Change

Background: Most studies that have assessed impacts on mortality of future temperature increases have relied on a small number of simulations and have not addressed the variability and sources of uncertainty in their mortality projections. Objectives: We assessed the variability of temperature projections and dependent future mortality distributions, using a large panel of temperature simulations based on different climate models and emission scenarios. Methods: We used historical data from 1990 through 2007 for Montreal, Quebec, Canada, and Poisson regression models to estimate relative risks (RR) for daily nonaccidental mortality in association with three different daily temperature metrics (mean, minimum, and maximum temperature) during June through August. To estimate future numbers of deaths attributable to ambient temperatures and the uncertainty of the estimates, we used 32 different simulations of daily temperatures for June–August 2020–2037 derived from three global climate models (GCMs) and a Canadian regional climate model with three sets of RRs (one based on the observed historical data, and two on bootstrap samples that generated the 95% CI of the attributable number (AN) of deaths). We then used analysis of covariance to evaluate the influence of the simulation, the projected year, and the sets of RRs used to derive the attributable numbers of deaths. Results: We found that < 1% of the variability in the distributions of simulated temperature for June–August of 2020–2037 was explained by differences among the simulations. Estimated ANs for 2020–2037 ranged from 34 to 174 per summer (i.e., June–August). Most of the variability in mortality projections (38%) was related to the temperature–mortality RR used to estimate the ANs. Conclusions: The choice of the RR estimate for the association between temperature and mortality may be important to reduce uncertainty in mortality projections. Citation: Benmarhnia T, Sottile MF, Plante C, Brand A, Casati B, Fournier M, Smargiassi A. 2014. Variability in temperature-related mortality projections under climate change. Environ Health Perspect 122:1293–1298; http://dx.doi.org/10.1289/ehp.130695

LightSail Program Status: One Down, One to Go

The LightSail program involves two 3U CubeSats designed to advance solar sailing technology state of the art. The entire program is privately funded by members and supporters of The Planetary Society, the world’s largest nonprofit space advocacy organization. Spacecraft design started in 2009; by the end of 2011 both spacecraft had largely been built but not fully tested, and neither had a firm launch commitment. Following an 18-month program pause during 2012-2013, the effort was resumed after launch opportunities had been secured for each spacecraft. The first LightSail spacecraft—dedicated primarily to demonstrating the solar sail deployment process—was launched into Earth orbit on 2015 May 20 as a secondary payload aboard an Atlas 5 rocket, and on June 9 mission success was declared. The mission plan for the second LightSail includes demonstration of solar sailing in Earth orbit, among other objectives. It is on track for a launch in 2016 aboard a Falcon Heavy rocket as a key element of the Prox-1 mission. Lessons learned from the 2015 test mission will be applied to the 2016 mission, and lessons from both LightSail missions will inform planned NASA solar sail-based CubeSat missions and hopefully enhance their chances for mission success

Gestational and Lactational Exposure to an Environmentally Relevant Mixture of Brominated Flame Retardants Downregulates Junctional Proteins, Thyroid Hormone Receptor α1 Expression, and the Proliferation-Apoptosis Balance in Mammary Glands Post Puberty

International audienceMammary gland development requires hormonal regulation during puberty, pregnancy and lactation. Brominated flame retardants (BFRs) are endocrine disruptors; they are added to consumer products to satisfy flammability standards. Previously, we showed that gestational and lactational exposure to an environmentally-relevant mixture of BFRs disrupts proteins of the adherens junctions in rat dam mammary glands at weaning. Here, we hypothesize that perinatal exposure to the same BFR mixture also disrupts junctional proteins and signaling pathways controlling mammary gland development in pups. Dams were exposed through diet to a BFR mixture based on the substances in house dust; doses of the mixture used were 0, 0.06, 20 or 60 mg/kg/day. Dams were exposed continuously beginning prior to mating until pups' weaning; female offspring were euthanized on postnatal day (PND) 21, 46 and 208. The lowest dose of BFRs significantly down-regulated adherens junction proteins, E-cadherin and β-catenin, and the gap junction protein p-Cx43, as well as thyroid hormone receptor alpha1 protein at PND 46. No effects were observed on estrogen or progesterone receptors. The low dose also resulted in a decrease in cleaved-caspase 3, a downward trend in PARP levels, proteins involved in apoptosis, and an upward trend in PCNA, a marker of proliferation. No effects were observed on ductal elongation or on the numbers of terminal end buds. Together, our results indicate that gestational and lactational exposure to an environmentally-relevant mixture of BFRs disrupts cell-cell interactions, thyroid hormone homeostasis and the proliferation-apoptosis balance at PND 46, a critical stage for mammary gland development