Bringing Deep Space Missions Within Reach for Small Spacecraft

There is growing interest in using small spacecraft for science and exploration beyond low Earth orbit, but these missions have been constrained to fly as secondary payloads on rideshare missions that launch infrequently and on less-than-ideal trajectories. Regular, dedicated, low-cost science missions to planetary destinations can be enabled by Rocket Lab’s high-ΔV small spacecraft, the high-energy Photon, supporting expanding opportunities for scientists and increasing the rate of science return. High-energy Photon can launch on Rocket Lab’s Electron launch vehicle to precisely target escape asymptotes for planetary small spacecraft missions with payload masses up to ~40 kg without the need for a medium or heavy lift launch vehicle. High-energy Photon can also fly as a secondary payload on an EELV Secondary Payload Adapter (ESPA) Grande port or on other launch vehicles, like Neutron. This paper describes planetary small spacecraft currently in development that leverage Rocket Lab’s deep space capabilities, including missions to the Moon, Venus, and Mars. The high-energy Photon will be demonstrated on the NASA Cislunar Autonomous Positioning System Technology Operations and Navigation Experiment (CAPSTONE) mission, launching in 2021. CAPSTONE is expected to be the first spacecraft to operate in a Near Rectilinear Halo Orbit (NRHO) around the Moon, with high-energy Photon delivering NASA’s 12U technology demonstration CubeSat on a Ballistic Lunar Transfer using a phasing orbit approach. The CAPSTONE high-energy Photon will launch on Electron. While NASA performs the primary mission, Rocket Lab plans to execute a secondary mission to demonstrate the high-energy Photon deep space operations capabilities with a lunar flyby. Rocket Lab has also made the engineering and financial commitment to fly a private mission to Venus in 2023 to help answer the question, “Are we alone in the universe?” The mission will deploy a small probe into the atmosphere in search of biomarkers. The mission is planned for launch in May 2023 on Electron from Rocket Lab’s Launch Complex-1. The mission will follow a hyperbolic trajectory with the high-energy Photon performing as the cruise stage and then as a communications relay after deploying a small probe for the science phase of the mission. In early 2021, Rocket Lab was awarded a contract for the preliminary design of two Photon spacecraft for the Escape and Plasma Acceleration and Dynamics Explorers (ESCAPADE) mission. ESCAPADE is a twin-spacecraft science mission that will orbit a pair of spacecraft around Mars to understand the structure, composition, variability, and dynamics of Mars\u27 unique hybrid magnetosphere. After launch as secondary payloads on a commercial launch vehicle provided by NASA, the two spacecraft will each execute a series of burns with the Hyper Curie engine to prepare for and execute the Trans-Mars Injection (TMI), perform an 11-month interplanetary cruise with several trajectory correction maneuvers (TCMs), and then perform the Mars Orbit Insertion (MOI) burns to insert into elliptical orbits around Mars. ESCAPADE is undergoing a NASA preliminary design review and a confirmation review in the summer of 2021 to evaluate whether the mission proceeds to implementation and flight

Molecular Cloud Evolution VI. Measuring cloud ages

This article has been published in Monthly Notices of the Royal Astronomical Society © 2018 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.In previous contributions, we have presented an analytical model describing the evolution and star formation rate (SFR) of molecular clouds (MCs) undergoing hierarchical gravitational contraction. The cloud’s evolution is characterized by an initial increase in its mass, density, SFR, and star formation efficiency (SFE), as it contracts, followed by a decrease of these quantities as newly formed massive stars begin to disrupt the cloud. The main parameter of the model is the maximum mass reached by the cloud during its evolution. Thus, specifying the instantaneous mass and some other variable completely determines the cloud’s evolutionary stage. We apply the model to interpret the observed scatter in SFEs of the cloud sample compiled by Lada et al. as an evolutionary effect so that, although clouds such as California and Orion A have similar masses, they are in very different evolutionary stages, causing their very different observed SFRs and SFEs. The model predicts that the California cloud will eventually reach a significantly larger total mass than the Orion A cloud. Next, we apply the model to derive estimated ages of the clouds since the time when approximately 25 per cent of their mass had become molecular. We find ages from ∼1.5 to 27 Myr, with the most inactive clouds being the youngest. Further predictions of the model are that clouds with very low SFEs should have massive atomic envelopes constituting the majority of their gravitational mass, and that low-mass clouds (M ∼ 103–104M⊙) end their lives with a mini-burst of star formation, reaching SFRs ∼300–500M⊙ Myr−1. By this time, they have contracted to become compact (∼1 pc) massive star-forming clumps, in general embedded within larger giant molecular clouds.Peer reviewe

Evaluating Four Inosine-Uridine Preferring Nucleoside Hydrolases in Bacillus Anthracis for Decontamination Strategies

Andrew Roser­ is a doctoral student in the School of Biological Sciences at Louisiana Tech University. Abigail Bass, Sophie Bott, Madison Brewton, Adam Broussard, Taylor Clement, Makenzie Cude, Hunter Currie, Claire Herke, Mary Hickman, Lauren James, Hailey Johnson, Madeline Lechtenberg, Sarah Murchison, Alex Plaisance, Wil Plants, Alex Sullivan, Sara Vandenberg, and Kaitlynn Willis are undergraduate students in the School of Biological Sciences at Louisiana Tech University. Rebecca Giorno is an Associate Professor in the School of Biological Sciences at Louisiana Tech University

Conserving the Stage: Climate Change and the Geophysical Underpinnings of Species Diversity

Conservationists have proposed methods for adapting to climate change that assume species distributions are primarily explained by climate variables. The key idea is to use the understanding of species-climate relationships to map corridors and to identify regions of faunal stability or high species turnover. An alternative approach is to adopt an evolutionary timescale and ask ultimately what factors control total diversity, so that over the long run the major drivers of total species richness can be protected. Within a single climatic region, the temperate area encompassing all of the Northeastern U.S. and Maritime Canada, we hypothesized that geologic factors may take precedence over climate in explaining diversity patterns. If geophysical diversity does drive regional diversity, then conserving geophysical settings may offer an approach to conservation that protects diversity under both current and future climates. Here we tested how well geology predicts the species diversity of 14 US states and three Canadian provinces, using a comprehensive new spatial dataset. Results of linear regressions of species diversity on all possible combinations of 23 geophysical and climatic variables indicated that four geophysical factors; the number of geological classes, latitude, elevation range and the amount of calcareous bedrock, predicted species diversity with certainty (adj. R2 = 0.94). To confirm the species-geology relationships we ran an independent test using 18,700 location points for 885 rare species and found that 40% of the species were restricted to a single geology. Moreover, each geology class supported 5–95 endemic species and chi-square tests confirmed that calcareous bedrock and extreme elevations had significantly more rare species than expected by chance (P<0.0001), strongly corroborating the regression model. Our results suggest that protecting geophysical settings will conserve the stage for current and future biodiversity and may be a robust alternative to species-level predictions

Stellar photometry with the Hubble Space Telescope Wide-field/Planetary camera - A progress report

We describe the prospects for the use of the Wide-Field/Planetary Camera (WFPC) for stellar photometry. The large halos of the point-spread function (PSF) resulting from spherical aberration and from spatial, temporal, and color variations of the PSF are the main limitations to accurate photometry. Degradations caused by crowding are exacerbated by the halos of the PSF. Here we attempt to quantify these effects and determine the current accuracy of stellar photometry with the WFPC. In realistic cases, the brighter stars in crowded fields have 0.09 mag errors; fainter stars have larger errors depending on the degree of crowding. We find that measuring Cepheids in Virgo Cluster galaxies is not currently possible without inordinate increases in exposure times

Resolving dual binding conformations of cellulosome cohesin-dockerin complexes using single-molecule force spectroscopy

Receptor-ligand pairs are ordinarily thought to interact through a lock and key mechanism, where a unique molecular conformation is formed upon binding. Contrary to this paradigm, cellulosomal cohesin-dockerin (Coh-Doc) pairs are believed to interact through redundant dual binding modes consisting of two distinct conformations. Here, we combined site-directed mutagenesis and single-molecule force spectroscopy (SMFS) to study the unbinding of Coh:Doc complexes under force. We designed Doc mutations to knock out each binding mode, and compared their single-molecule unfolding patterns as they were dissociated from Coh using an atomic force microscope (AFM) cantilever. Although average bulk measurements were unable to resolve the differences in Doc binding modes due to the similarity of the interactions, with a single-molecule method we were able to discriminate the two modes based on distinct differences in their mechanical properties. We conclude that under native conditions wild-type Doc from Clostridium thermocellum exocellulase Cel48S populates both binding modes with similar probabilities. Given the vast number of Doc domains with predicteddual binding modes across multiple bacterial species, our approach opens up newpossibilities for understanding assembly and catalytic properties of a broadrange of multi-enzyme complexes

The first oviraptorosaur (Dinosauria: Theropoda) bonebed: Evidence of gregarious behaviour in a maniraptoran theropod

A monodominant bonebed of Avimimus from the Nemegt Formation of Mongolia is the first oviraptorosaur bonebed described and the only recorded maniraptoran bonebed from the Late Cretaceous. Cranial elements recovered from the bonebed provide insights on the anatomy of the facial region, which was formerly unknown in Avimimus. Both adult and subadult material was recovered from the bonebed, but small juveniles are underrepresented. The taphonomic and sedimentological evidence suggests that the Avimimus bonebed represents a perimortem gregarious assemblage. The near absence of juveniles in the bonebed may be evidence of a transient age-segregated herd or ‘flock’, but the behaviour responsible for this assemblage is unclear. Regardless, the Avimimus bonebed is the first evidence of gregarious behaviour in oviraptorosaurs, and highlights a potential trend of increasing gregariousness in dinosaurs towards the end of the Mesozoic

Reduction of PG:1115+080 Images

The data are three exposures in PC6 through F785LP obtained on March 3, 1991. The exposure times are 120, 400, and 400 seconds. The data are reduced with the "standard" WFPC reduction scheme: A-to-D correction, DC bias subtraction, AC bias subtraction, dark current subtraction, preflash subtraction, and flat field normalization, using the best available calibration data. The exposures are combined into a weighted average normalized to 400 seconds exposure time, so one DN (data number) is about 17.25 electrons. At this step, cosmic rays are removed by intercomparison of the three images

Servant Leadership and Follower Job Performance: The Mediating Effect of Public Service Motivation

This article advances our understanding of the effects of servant leadership, an employee- and community-focused leadership style, on followers’ public service motivation (PSM) and job performance. Based on social learning theory, we argue that by emphasizing to their followers the importance of serving others both inside and outside the organization and by acting as role models by serving others themselves, servant leaders enhance job performance by engendering higher PSM in their followers. A multi-level analysis of three waves of multi-source data from a Chinese government agency reveals that PSM mediates the influence that servant leadership has on followers’ job performance. The results are consistent with the theoretical predications that the altruistic behaviour displayed by servant leaders elicits higher levels of the altruistic behaviours that characterize PSM, which in turn increases job performance. Hence, this study contributes to our overall understanding of how leadership drives performance in the public sector

Facilitating knowledge exchange between health-care sectors, organisations and professions: A longitudinal mixed-methods study of boundary-spanning processes and their impact on health-care quality

Background: Relatively little is known about how people and groups who function in boundary-spanning positions between different sectors, organisations and professions contribute to improved quality of health care and clinical outcomes. Objectives: To explore whether or not boundary-spanning processes stimulate the creation and exchange of knowledge between sectors, organisations and professions and whether or not this leads, through better integration of services, to improvements in the quality of care. Design: A 2-year longitudinal nested case study design using mixed methods. Setting: An inner-city area in England (‘Coxford’) comprising 26 general practices in ‘Westpark’ and a comparative sample of 57 practices. Participants: Health-care and non-health-care practitioners representing the range of staff participating in the Westpark Initiative (WI) and patients. Interventions: The WI sought to improve services through facilitating knowledge exchange and collaboration between general practitioners, community services, voluntary groups and acute specialists during the period late 2009 to early 2012. We investigated the impact of the four WI boundary-spanning teams on services and the processes through which they produced their effects. Main outcome measures: (1) Quality-of-care indicators during the period 2008–11; (2) diabetes admissions data from April 2006 to December 2011, adjusted for deprivation scores; and (3) referrals to psychological therapies from January 2010 to March 2012. Data sources: Data sources included 42 semistructured staff interviews, 361 hours of non-participant observation, 36 online diaries, 103 respondents to a staff survey, two patient focus groups and a secondary analyses of local and national data sets. Results: The four teams varied in their ability to, first, exchange knowledge across boundaries and, second, implement changes to improve the integration of services. The study setting experienced conditions of flux and uncertainty in which known horizontal and vertical structures underwent considerable change and the WI did not run its course as originally planned. Although knowledge exchanges did occur across sectoral, organisational and professional boundaries, in the case of child and family health services, early efforts to improve the integration of services were not sustained. In the case of dementia, team leadership and membership were undermined by external reorganisations. The anxiety and depression in black and minority ethnic populations team succeeded in reaching its self-defined goal of increasing referrals from Westpark practices to the local well-being service. From October to December 2010 onwards, referrals have been generally higher in the six practices with a link worker than in those without, but the performance of Westpark and Coxford practices did not differ significantly on three national quality indicators. General practices in a WI diabetes ‘cluster’ performed better on three of 17 Quality and Outcomes Framework (QOF) indicators than practices in the remainder of Westpark and in the wider Coxford primary care trust. Surprisingly, practices in Westpark, but not in the diabetes cluster, performed better on one indicator. No statistically significant differences were found on the remaining 13 QOF indicators. The time profiles differed significantly between the three groups for elective and emergency admissions and bed-days. Conclusions: Boundary spanning is a potential solution to the challenge of integrating health-care services and we explored how such processes perform in an ‘extreme case’ context of uncertainty. Although the WI may have been a necessary intervention to enable knowledge exchange across a range of boundaries, it was not alone sufficient. Even in the face of substantial challenges, one of the four teams was able to adapt and build resilience. Implications for future boundary-spanning interventions are identified. Future research should evaluate the direct, measurable and sustained impact of boundary-spanning processes on patient care outcomes (and experiences), as well as further empirically based critiques and reconceptualisations of the socialisation→externalisation→combination→internalisation (SECI) model, so that the implications can be translated into practical ideas developed in partnership with NHS managers. Funding: The National Institute for Health Research Health Services and Delivery Research programme