Envelope Size Research Articles

Design and application of deployable heat radiator

Abstract Limited by the envelope size of the launch vehicle, comparing with the body-mounted radiator of the traditional spacecraft, the thermal control scheme based on single-phase fluid loop is proposed in order to improve the system-level heat dissipation. The thermal analysis model of the deployable heat radiator, including the spacecraft, is established. Through the comparative analysis of the fin parameter, infrared radiation effect, and working fluid selection, the heat dissipation efficiency of the radiator is improved, and the first flight application of the deployable heat radiator is realized. The research results show that in view of the GEO spacecraft’s bad external heat flow condition, the heat dissipation of a single radiator can reach 250W/m2 above; the method of using multiple deployable heat radiators can effectively solve the problem of insufficient heat dissipation capacity on the spacecraft.

Scaling Laws for Deployable Mesh Reflector Antennas

This paper begins with the formulation of a general, rapid design method for deployable mesh reflector antennas based on the AstroMesh architecture. This method is then used to obtain estimates of the total mass, stowed envelope size, and fundamental natural frequency of vibration for antennas with a range of aperture diameters and focal lengths, assuming an operational radio frequency of 10 GHz. A study of the scaling trends of this reflector design shows that the distribution of prestress in the inner tension structure has a major impact on the mass of the outer perimeter truss. Based on this result, a prestress optimization problem to design reflectors of minimum mass is formulated, and analytical scaling laws are obtained for the mass, stowed envelope, and natural frequency of optimally prestressed reflectors with aperture diameters up to 200 m. It is then shown that aperture diameters of 70–100 m are at the limit of launchers that are currently available or under development. A semianalytical homogenization model that accurately estimates the fundamental natural frequencies for batten-supported and free-free boundary conditions is also presented.

Photons from Neutrinos: The Gamma-Ray Echo of a Supernova Neutrino Burst

When a star undergoes core collapse, a vast amount of energy is released in a ∼10 s long burst of neutrinos of all species. Inverse beta decay in the star’s hydrogen envelope causes an electromagnetic cascade that ultimately results in a flare of gamma rays—an “echo” of the neutrino burst—at the characteristic energy of 0.511 MeV. We study the phenomenology and detectability of this flare. Its luminosity curve is characterized by a fast, seconds-long rise and an equally fast decline, with a minute- or hour-long plateau in between. For a near-Earth star (distance D ≲ 1 kpc) the echo will be observable at near future gamma-ray telescopes with an effective area of 103 cm2 or larger. Its observation will inform us on the envelope size and composition. In conjunction with the direct detection of the neutrino burst, it will also give information on the neutrino emission away from the line of sight and will enable tests of neutrino propagation effects between the stellar surface and Earth.

Miniaturization design of laser detection device for naval gun composite fuse

Naval gun weapons are the only weapon system on board that can undertake various combat tasks such as shore fire support, sea attack, air defense and missile defense, and rapid response to emergencies. A new type of naval gun laser-radio composite fuse(naval gun composite fuse) is proposed to address the issue of naval gun fuses being susceptible to interference and failure in a single radio proximity system. This improves the multiple operational effectiveness of naval guns and the adaptability of naval gun ammunition to electromagnetic and other interference environments. In response to the limitation of small size of naval gun fuses, the overall structure and miniaturized laser detection device were designed separately. Firstly, a miniaturized 4-channel narrow pulse high repetition frequency laser detection method with uniform forward circumferential distribution is adopted to achieve compatibility with the original naval gun fuse structure, the simulation results indicate that the structural deformation and strength meet the requirements. Secondly, by designing a laser emission collimating lens that is glued together with a small spherical lens and a small concave cylindrical mirror, the outer envelope size is only Φ5x3mm. The simulation results show that at a distance of 20mm from the laser emission window, the spot diameter is 0.66mm and the divergence angle is 1.9 °, achieving good laser collimation and miniaturization of the emission optical system. Finally, the receiving optical system reduces its volume by adding a receiving objective and a field mirror. The effective aperture of the receiving objective is 10mm, the diameter of the field mirror is 5mm, the focal length is 11.1mm, and the receiving field angle is 5 °. The simulation results show that the laser spot radius on the photosensitive surface of the photodetector is 0.06mm, which meets the requirements of photodetectors.

Accretion of primordial H–He atmospheres in mini-Neptunes: The importance of envelope enrichment

Context. Out of the more than 5000 detected exoplanets, a considerable number belong to a category called “mini-Neptunes”. Interior models of these planets suggest that they have primordial H–He-dominated atmospheres. As this type of planet is not found in the Solar System, understanding their formation is a key challenge in planet formation theory. Unfortunately, quantifying how much H–He planets have, based on their observed mass and radius, is impossible due to the degeneracy of interior models. Aims. Another approach to estimating the range of possible primordial envelope masses is to use formation theory. As different assumptions in planet formation can heavily influence the nebular gas accretion rate of small planets, it is unclear how large the envelope of a protoplanet should be. We explore the effects that different assumptions regarding planet formation have on the nebular gas accretion rate, particularly by exploring the way in which solid material interacts with the envelope. This allows us to estimate the range of possible post-formation primordial envelopes. Thereby, we demonstrate the impact of envelope enrichment on the initial primordial envelope, which can be used in evolution models. Methods. We applied formation models that include different solid accretion rate prescriptions. Our assumption is that mini-Neptunes form beyond the ice line and migrate inward after formation; thus, we formed planets in situ at 3 and 5 au. We considered that the envelope can be enriched by the accreted solids in the form of water. We studied how different assumptions and parameters influence the ratio between the planet’s total mass and the fraction of primordial gas. Results. The primordial envelope fractions for low- and intermediate-mass planets (total mass below 15 M⊕) can range from 0.1% to 50%. Envelope enrichment can lead to higher primordial mass fractions. We find that the solid accretion rate timescale has the largest influence on the primordial envelope size. Conclusions. Rates of primordial gas accretion onto small planets can span many orders of magnitude. Planet formation models need to use a self-consistent gas accretion prescription.

An EU Fund to Incentivise Public Investments with Positive Externalities

Abstract This contribution, based on the proposals by Bakker, Beetsma, and Buti (2024a. “The Case for a European Public-Goods Fund.” Project Syndicate, 4 March. https://www.project-syndicate.org/commentary/public-goods-fund-could-finance-green-transition-and-ensure-fiscal-responsibility-by-age-bakker-et-al-2024-03, 2024b. “Two Birds with One Stone: Investing in European Public Goods while Maintaining Fiscal Discipline at Home.” Intereconomics 59 (2): 1–6), discusses an EU fund to finance investments with positive cross-border spill-overs, such as large infrastructures, that are too expensive for individual countries to finance, or of which the benefits are insufficiently internalised by individual investing countries. Each country receives a given part (“envelope”) of the fund. The envelope size and the contribution as well as the eventual debt repayment burden could be proportional to the size of the economy, thereby minimising cross-border redistribution. Access to the fund’s resources is conditional on adherence to the EU’s new fiscal rulebook. If a country fails to make full use of its envelope, the remaining resources are re-allocated over the other envelopes. Hence, the fund provides an incentive for countries to simultaneously undertake investments that benefit groups of countries or the EU at large, and to maintain fiscal discipline. We discuss the size of the fund, how it fits within the EU current instrument set, its governance, its financing and its potential political appeal.

Stiffness Design of Active Capture Claw-Type Docking Mechanism for Lunar Sample Return

The docking mechanism is the key system for realizing the lunar-orbit docking mission of two spacecraft, which needs to have both capture correction and connection hold functions. The different stiffness requirements between the capture correction process, where low stiffness is desired, and the connection hold process, where high stiffness is desired, pose a significant challenge to the design of the docking mechanism. In this paper, an active capture claw docking mechanism is designed. Under the constraints of being lightweight and having an envelope size, three sets of independent claw mechanisms are designed using the modular design idea to achieve the performance optimization and function integration of the docking mechanisms. The theoretical model of the collision dynamics between the active and passive docking mechanisms is established; the stiffness value range of the docking mechanism is determined, and the typical docking conditions are simulated and verified. The results show that the stiffness design in this paper can satisfy the requirements of the two docking processes. The active capture claw docking mechanism developed was applied to the lunar surface sample return mission successfully and played an important role in the lunar-orbit docking mission.

Lithium depletion in solar analogs: age and mass effects

ABSTRACT The main goal of this work is to evaluate the correlation between Li abundance, age, and mass. Using high-quality ESO/HARPS data (R ≃ 115 000; 270 ≤ SNR ≤ 1000), we measured Li abundances via spectral synthesis of the 6707.8 Å 7Li line in 74 solar twins and analogs. Our joint analysis of 151 Sun-like stars (72 from our sample plus 79 solar twins from a previous study) confirms the strong Li abundance–age correlation reported by other works. Mass and convective envelope size also seem to be connected with Li abundance but with lower significance. We have found a link between the presence of planets and low Li abundances in a sample of 192 stars with a high significance. Our results agree qualitatively with non-standard models, and indicate that several extra transport mechanisms must be taken into account to explain the behaviour of Li abundance for stars with different masses and ages.

Reversible SOFC/SOEC System Development and Demonstration

The OxEon Energy team continues its 30+ year solid oxide fuel cell (SOFC) development history with the design, fabrication, and installation of two reversible solid oxide electrolysis (SOEC)/SOFC demonstration modules (rSOC), at Idaho National Laboratory (INL) and a private, stand-alone microgrid, scheduled for installation and commissioning in early 2023. OxEon’s SOEC/SOFC technology builds on the success of the SOEC stack installed on NASA’s Mars Perseverance Rover that has produced high-purity O2 by electrolyzing Mars atmosphere CO2 nine times to date.OxEon Energy’s technology space integrates cross-sector coupling to produce hydrogen or syngas from SOEC, electricity via SOFC, and transportation fuels from syngas through Fischer-Tropsch synthesis. A low energy plasma reformer provides an alternative approach of producing syngas from low value hydrocarbons. OxEon’s four complementary technologies enable a flexible approach to leveling fluctuating energy from renewables and converting it to accessible, storable, and higher value fuels and chemicals. The reversible SOEC/SOFC systems described in this work demonstrate the opportunity to generate and store H2 fuel as a method to stabilize and capture excess production from renewable or nuclear energy sources.The two demonstration units described in this work integrate OxEon’s reversible SOEC/SOFC stacks with an effective and reliable balance of plant (BOP) system. The high temperature electrolysis (HTE) systems produce hydrogen through electrolysis using solid oxide cell (SOC) technology derived from OxEon’s heritage stack technology and the advancements made during the development of stacks for NASA’s Mars2020 mission.The two demonstration units described in this work use the same modular system design based on 4-stack quad assemblies. The INL system consists of three 4-stack quad assemblies to meet the 30 kW SOEC/ 10 kW SOFC target. OxEon also designed the manifold and plenum assembly to interface with INL’s existing 50 kW test stand and scaled the hot section unit (HSU) to enclose the system. Pressure drop across the system is minimized by supplying even flow to each of the three stack quads, and allows for air delivery in SOFC mode with a blower rather than an air compressor. INL system installation and testing is scheduled for early 2023. A previous 10 kW SOEC system demonstration at INL exceeded project objectives with 14.5 kW system power output, with uniform performance measured from each of 4 stacks.OxEon is scheduled to deliver a 20 kW SOEC/ 10 kW SOFC system to the private microgrid at Stone Edge Farm in early 2023. The system is comprised of 2 quad modules and BOP that will connect with onsite hydrogen storage and renewable energy generation plant. The system will generate hydrogen in SOEC mode using renewable energy supplied by the farm’s solar array. Hydrogen produced in SOEC mode will be compressed and stored by a system designed by HyET Hydrogen B.V. During times of low renewable power generation, the SOFC system will use stored hydrogen to generate power.The Stone Edge Farm system includes two heat exchangers (one for air, one for fuel) that raise the gas feeds to within 50 ⁰C of operating conditions, and minimize pre-heating required for operation. Pre-heating is accomplished with heaters in the HSU enclosure. The feed path is routed to use a portion of the exotherm generated in SOFC mode. The air heat exchanger is oversized for SOEC mode but sized to accommodate the excess flow required for cooling in SOFC mode. The fuel heat exchanger is sized appropriately to deliver H2 in SOFC operation and steam in SOEC operation.Both systems apply mechanical compression to the stacks outside of the HSU enclosure. This design produces greater force than if the springs are enclosed in the hot zone and reduces the insulation envelope size. The end load is applied through a loading rod, an upper load plate, layers of insulation, and an additional outer load plate, placing the springs outside the insulation package that surrounds the hot region where the stacks are located. Low thermal conductivity ceramic rods minimize heat loss through the load transmission path.The materials set used in the rSOC systems uses a scandia-stabilized zirconia electrolyte-supported cell design with nickel-cermet fuel electrode and perovskite air electrodes. Green electrolyte is tape cast, cut, and fired to produce a dense electrolyte of about 250 microns thickness. Electrode inks are applied via screen printing, then fired to form porous electrode layers. Recent advancements in the air side electrode barrier layer, air electrode layers, and fuel electrode catalyst have improved stack performance and stability. Figure 1

Reversible SOFC/SOEC System Development and Demonstration

The OxEon Energy team continues its 30+ year solid oxide fuel cell (SOFC) development history with the design, fabrication, and installation of two reversible solid oxide electrolysis (SOEC)/SOFC demonstration modules scheduled for installation and commissioning in 2023. The high temperature electrolysis (HTE) systems produce hydrogen through electrolysis using solid oxide cell (SOC) technology derived from OxEon’s heritage stack technology and advancements made during stack development for NASA’s Mars2020 mission. The demonstration units integrate reversible SOC stacks with an effective and reliable balance of plant (BOP) system. A 4-stack quad assembly forms the basis for a modular, scalable system. Thermal management includes pre-heaters within the hot section unit (HSU) enclosure and a feed path that takes advantage of the exotherm generated in SOFC mode. The system design applies mechanical compression to the stacks outside the HSU enclosure to minimize insulation envelope size and produce greater force on the stacks.

Design method of combined stiffened pressure hulls with variable-curvature characteristic

This study presents a combined pressure hull design method with variable-section ribs. This method for determining the length-radius ratio of the pressure hull's bearing unit is derived based on the stiffness-matching characteristic of the shell and stiffener. The bearing mechanism of variable curvature stiffened shell is discussed through theoretical derivation and numerical simulation. The design scheme of variable cross-section and the equal-stiffness rib is proposed to address the limitations of outer envelope size and inner space utilization of the pressure hull. Its buckling load is determined by the energy method. The design approach for a new type of stiffened pressure hull is summarized. In addition, the method is verified by the design example and the experiment. The results revealed that the combined variable curvature shells are a superior pressure hull configuration. Compared to the cylindrical stiffened shell, the buckling load of the pressure hull with variable cross-section ribs can be improved significantly (about 26.7%). At the same time, space utilization remains at the original level. The stiffened design technique described in this research based on elastic buckling theory can accurately determine the length-radius ratio of the bearing unit, relying on the design objective with high feasibility.

Effects of the skirt length and embedment depth on the capacity of a skirted spudcan foundation under combined loading

Skirted spudcan foundations can provide a considerable bearing capacity and moment fixity for resisting the complex combined vertical, horizontal, and moment loadings arising from the harsh environment in the offshore oil and gas industry. These potential benefits are conducive to the extension of mobile jack-up drilling rigs into deep water. In this study, a series of probe tests were carried out using finite element analysis to investigate the effects of the skirt length and embedment depth on the bearing capacity of skirted spudcan foundations in soft clay under combined loading. The results indicate that both the skirt length and the embedment depth can significantly affect the behavior of a skirted spudcan and apparently improve the various bearing capacities under combined loading. As the skirt length and embedment depth increase, the failure envelope's size gradually expands and the failure envelope's shape changes accordingly. A spudcan with a skirt length of 0.25D embedded in about 2D of sediments is suggested to obtain an optimal application in practice. A closed-form algebraic expression was derived to interpret and predict the behavior of skirted spudcan foundations, which properly considers the effects of the skirt length and embedment depth.

Experimenting with QR Codes and Envelope Size in Push-to-Web Surveys

Abstract Survey researchers are continually evaluating approaches to increase response rates, especially those that can be implemented with little or no costs. In this study, we experimentally evaluated whether or not including Quick Response (QR) codes in mailed recruitment materials for self-administered web surveys increased web survey participation. We also assessed whether mailing these materials in a non-standard envelope size (6 × 9 inch) yielded a higher response rate than invitations mailed in a standard, #10 envelope (4.125 × 9.5 inch). These experiments were embedded in a sequential mixed-mode (dual-frame phone and web) statewide survey. Including a QR code (in addition to a URL) significantly increased the response rate compared to invitations that only included a URL in our study. As expected, a consequence of including the QR code was an elevated number of completions on smartphones or tablets among households randomly assigned to the QR code condition. The use of a larger (6 × 9 inch) envelope did not affect the overall response rate but did significantly boost the response rate for the landline sample (envelopes addressed to “STATE resident”) while having little effect for the wireless sample (envelopes addressed by name). This study suggests that incorporating both QR codes and larger (6 × 9 inch) envelopes in mail recruitment materials for web surveys is a cost-effective approach to increase web participation.

Single Use or Disposable Flexible Bronchoscopes: Bench Top and Preclinical Comparison of Currently Available Devices.

Data regarding the risk of infection related to reusable bronchoscopes, the global drive toward disposable technology and the COVID-19 pandemic have led to an increase in the use and production of single use or disposable bronchoscopes. An in-depth comparison of all available devices has not been published. A benchtop comparison of the Ambu®aScopeTM, Boston Scientific® EXALTTM Model B, the Surgical Company Broncoflex© Vortex, Pentax® Medical ONE Pulmo™, and Vathin® H-SteriscopeTM (all 2.8 mm inner dimension other than the Pentax single-use flexible bronchoscope (3 mm)) was undertaken including measurement of maximal flexion and extension angles, thumb force required and suction with and without biopsy forceps. Thereafter, preclinical assessment was performed with data collected including experience, gender, hand size, and scope preference. The Vathin single-use flexible bronchoscope had the biggest range of tip movement from flexion to extension with and without forceps. The Boston single-use flexible bronchoscope required the maximal thumb force but had the least reduction of tip movement with forceps. The Boston single-use flexible bronchoscope significantly outperformed all other scopes including the standard Pentax scope and was the only scope capable of suctioning pseudo-mucus around the forceps. Although there was no significant difference in preference in the overall group, females and those with smaller hand size preferred the Pentax and males the Broncoflex single-use flexible bronchoscope. Currently available single-use flexible bronchoscopes differ in several factors other than scope sizes and monitor including suction, turning envelope, and handle size. Performance in the clinical setting will be key to their success.

New Papiliotrema laurentii UFV-1 strains with improved acetic acid tolerance selected by adaptive laboratory evolution

The production of yeast oil from lignocellulosic biomasses is impaired by inhibitors formed during the pretreatment step, mainly acetic acid. Herein, we applied Adaptive Laboratory Evolution (ALE) to select three Acetic acid Tolerant Strains (ATS) of P. laurentii UFV-1. Different phenotypes emerged alongside evolution. The ATS II presented trade-offs in the absence of acetic acid, suggesting that it displays a specialized phenotype of tolerance to growth on organic acids. On the other hand, ATS I and ATS III presented phenotypes associated with the behavior of generalists. ATS I was considered the most promising evolved strain as it displayed the oleaginous phenotype in all conditions tested. Thus, we applied whole-genome sequencing to detect the mutations that emerged in this strain during the ALE. We found alterations in genes encoding proteins involved in different cellular functions, including multidrug resistance (MDR) transporters, energy metabolism, detoxification, coenzyme recycling, and cell envelope remodeling. To evaluate acetic acid stress responses, both parental and ATS I strains were cultivated in chemostat mode in the absence and presence of acetic acid. In contrast to ATS I, the parental strain presented alterations in the cell envelope and cell size under acetic acid stress conditions. Furthermore, the parental strain and the ATS I presented differences regarding acetic acid assimilation. Contrary to the parental strain, the ATS I displayed an increase in unsaturated fatty acid content irrespective of acetic acid stress, which might be related to improved tolerance to acetic acid. Altogether, these results provided insights into the mechanisms involved with the acetic acid tolerance displayed by ATS I and the responses of P. laurentii to this stressful condition.

Theoretical and experimental study on vibration sensitivity of cubic cavity for space applications

The increasing performance of ultra-stable lasers has made them attractive for non-laboratory and space field applications. How to reduce the vibration sensitivity of the optical reference cavity is one of the key points. To develop vibration-insensitive cavity for space applications, we investigate the vibration sensitivity of a cubic cavity with the length of 100 mm theoretically and experimentally. The functional expression of the fractional length change of the cubic cavity versus the cutting depth of the cubic spacer vertices and the compressive forces is presented for the first time. The vibration sensitivity of the 100 mm cubic cavity is measured as low as 2 × 10−11/g. Based on the vibration-insensitive cubic cavity, a 1 Hz-linewidth laser system with an envelope size of 450 mm × 541 mm × 598 mm is developed, which would be the prototype for space applications.

Comparative Study of Biased Flux PM Machines Having Different Stator Core Segments and Armature Winding Configurations

This article proposes a comparative study of biased flux permanent magnet (BFPM) machines having different stator core segments and armature winding configurations. The topologies of the four investigated machines and their operating principles are introduced first. Then, in the case of same envelope size and copper loss, all four BFPM machines are designed based on the single variable optimization method to obtain higher average torque, along with their comparison of electromagnetic characteristics such as phase back-electromotive force (back EMF), cogging torque, and torque capability. It is shown that by exploiting both flux focusing (FC) and dual armature (DA) design, the average torque of the BFPM machine has a 132% sharp increase. Furthermore, to reveal the real performance of the DA-FC-BFPM machine, its comparison with machines such as DA doubly salient permanent magnet (DA-DSPM) machine, DA flux reversal permanent magnet (DA-FRPM) machine, DA flux switching permanent magnet (DA-FSPM) machine, wound rotor synchronous (WRS) machine, and surface-mounted permanent magnet (SPM) machine is performed. Finally, a prototype machine is built and tested to verify the finite-element predictions.

Component assignment and layout optimization for multi-module microsatellite considering variable module size

The general satellite component layout optimization problems have always focused on satellites with fixed module size, and each component is limited to a specific module or panel. In actual engineering practice, dimensions of microsatellite are no longer constrained strictly, but adjustable within an allowed range. The assignment of the components and the dimensions of the modules should be considered as variable to get better global performance. In this paper, a TS+DE+AFT hybrid algorithm is proposed to solve this component assignment and layout optimization problem for multi-module microsatellite (CALO-MM) considering variable module size, in which tabu search (TS) is mainly used to assign components to the appropriate module, and differential evolution (DE) is used to optimize the layout of the components in each module. An adaptive fine-tuning (AFT) strategy is applied to dynamically adjust the length and height of modules within a maximum envelope size. Demonstration and engineering cases are studied to verify the effectiveness of proposed hybrid algorithm.

Numerical investigation of heat transfer and flow resistance characteristics of interpenetrated flying-wing finned tubes

In the present study, three possible interpenetration modes named vertical insertion, horizontally staggered shift, and streamwise staggered shift are proposed to improve the compactness of the flying-wing finned tube heat exchanger. Also, the effects of these modes on heat transfer and flow resistance characteristics of the finned tubes are numerically analyzed in the Reynolds number range of 1500–3000. It was found that a large vertically embedded depth (Lv), which in the present study has a maximum value of 3.4 mm, creates an acute-angled slit in the fin gradual contraction region. This slit weakens the convective heat transfer. However, the flow resistance characteristic is improved to a certain extent with increasing Lv. It was also found that the monotonous characteristic curves obtain a local inflection point in the range of 2.35–3.05 mm of Lv. An equivalent insertion coefficient is proposed to simplify the comparison of heat transfer rate (Φ). When the envelope size of the heat exchanger core, finned tube number, and pressure drop (Δp) are fixed, the overall thermal-hydraulic characteristics (Φ versus Δp) of the interpenetrated flying-wing finned tube heat exchanger are most significantly improved with Lv equal to 2.7 mm by 6.5% on average. Finally, two interpenetration correction factors are proposed to quantify the effect of interpenetration on the thermal-hydraulic characteristics.

P46. COMPLICATIONS IN PREPECTORAL TISSUE EXPANDER PLACEMENT: A SINGLE INSTITUTION STUDY

PURPOSE: Prepectoral two-stage post-mastectomy breast reconstruction has increased in the recent time period. Benefits of prepectoral reconstruction may include lack of animation deformities and reduced post-operative pain, but its complication profile is currently unclear. The aim of this study is to examine the complication profile of prepectoral tissue expanders (TEs) at our institution. METHODS: We performed a retrospective review of patients who underwent immediate reconstruction with a prepectoral TE from 2018-2020 at Memorial Sloan Kettering Cancer Center. Basic demographics and comorbidities were evaluated. Outcomes of interest included seroma, hematoma, infection/cellulitis, mastectomy skin flap necrosis requiring revision (MSFN), TE exposure, capsular contracture, and TE loss. Multivariate logistic regression assessed factors associated with increased odds of TE loss. RESULTS: A total of 574 patients (952 TEs) were included. Overall, 78.6% of mastectomies were skin-sparing, 71.2% of TEs were smooth, 82.6% used acellular dermal matrix (ADM), and 46.6% used SPY angiography. Most frequent complications were seroma (9%), infection/cellulitis (8%), and TE loss (4.6%). Hematoma, TE exposure, and MSFN each had complication rates of 2%. Fewer than 1% of patients experienced capsular contracture. Diabetics (OR=1.09, p=0.02), former smokers (OR=2.45, p<0.01), and increasing mastectomy weight (OR=0.001, p=0.04) had increased odds of TE loss. TE loss was not associated with TE surface type, ADM use, or SPY use. CONCLUSION: Prepectoral reconstruction is a reasonable and safe alternative to subpectoral TE placement. Further research examining the quality of the soft tissue envelope and pocket size, as well as assessment of patient reported outcomes, would prove beneficial.