Risk of Increased Fragmentation Events Due to Low Altitude Large Constellation Spacecraft

Orbital debris experts and industry leaders are concerned about the added hazard that thousands of additional spacecraft would have on the future orbital debris environment. Large constellations proposals plan to deploy spacecraft at altitudes from 1100 km to 1300 km, where fragmentation debris can take thousands of years or longer to decay naturally, while other proposals include deploying spacecraft at station-keeping altitudes from 300 km to 600 km. Although these lower altitude spacecraft are compliant with the 25-year rule, there is still an increased risk of accidental explosions generating high velocity fragments that could damage international spacecraft assets. The NASA Orbital Debris Program Office (ODPO) has conducted several parametric studies that examine the potential negative environmental impacts of large constellation deployments. This study addresses the lower altitude constellations and the potential risk that they impose on the future environment during mission operations. The projected future environment is generated as the average of 100 LEGEND Monte Carlo (MC) simulation runs while adjusting parameters such as average probability of explosion and operational lifetime per constellation. Results of the effect of accidental explosions of large constellation spacecraft on the environment below 600 km altitude are analyzed

Penerapan Solution Focused Brief Therapy (Sfbt) Untuk Meningkatkan Harga Diri Siswa Kelas XI Bahasa SMA Al-islam Krian

Tujuan penelitian ini adalah untuk menguji penerapan Solution Focused Brief Therapy (SFBT) dalam meningkatkan harga diri siswa  kelas XI Bahasa SMA AL-ISLAM Krian. Penelitian ini menggunakan jenis penelitian pre-experimental dengan jenis one group pre-test dan post-test design. Subjek dalam penelitian ini berjumlah 5 siswa dari 24 siswa kelas XI Bahasa SMA AL-ISLAM Krian yang mempunyai harga diri rendah. Metode pengumpul data yang digunakan adalah angket harga diri siswa. Jenis angket yang digunakan angket tertutup dengan 4 alternatif jawaban yaitu sangat setuju, setuju,tidak setuju, dan sangat tidak setuju. Analisis data yang digunakan pada penelitian ini adalah statistic non parametric dengan uji tanda (sign test). Setelah diperoleh data hasil dari angket pre-test dan post-test, maka selanjutnya dapat dilakukan analisis dengan uji tanda, dapat diketahui ρ = 0,031 lebih kecil dari α sebesar 5% = 0,05. Dapat diartikan setelah diberikan perlakuan Solution Focused Brief Therapy mengalami peningkatan harga diri siswa. Dari hasil analisis data dapat diketahui ada perbedaan skor antara sebelum dan sesudah diberikan perlakuan yang menggunakan Solution Focused Brief Therapy dalam meningkatkan harga diri siswa kelas XI Bahasa SMA AL-ISLAM Krian. Sehingga dapat disimpulkan bahwa konseling solution focused brief therapy dapat digunakan untuk meningkatkan harga diri siswa kelas XI Bahasa SMA AL-ISLAM Krian. Kata kunci : Solution Focused Brief Therapy, Harga diri sisw

The Updated GEO Population for ORDEM 3.1

The limited availability of data for satellite fragmentations and debris in the geosynchronous orbit (GEO) region creates challenges to building accurate models for the orbital debris environment at such altitudes. Updated methods to properly incorporate and extrapolate measurement data have become a cornerstone of the GEO component in the newest version of the NASA Orbital Debris Engineering Model (ORDEM), ORDEM 3.1. For the GEO region, the Space Surveillance Network (SSN) catalog provides coverage down to a limit of approximately 1 m. A more statistically complete representation of the GEO population for smaller objects, which can pose a high risk to operational spacecraft, is thus dependent on dedicated observations by instruments optimized to observe debris smaller than the SSN cataloging threshold. For ORDEM 3.1, optical data from the Michigan Orbital DEbris Survey Telescope (MODEST) provided the input for building the GEO population down to approximately 30 cm (converting absolute magnitude to size). For smaller sizes, the size distribution of debris in the MODEST dataset was extrapolated down to 10 cm, and orbital parameters were estimated based on the orbits of the larger objects. When compared to previous versions of the model, significant improvements were made to the process of building the GEO population in ORDEM 3.1, both in the assessment of fragmentation debris in the data and assignment of orbital elements within the model. A so-called debris ring filter, based on a range of angles between an orbits angular momentum vector and that of the stable Laplace plane, was applied to the data to reduce biases from non- GEO objects, such as objects in a GEO-transfer orbit. In addition, a new approach was implemented to assign noncircular mean motions and eccentricities to the fragmentation debris observed by MODEST because the short observation window (5 min) in GEO limits orbit resolution to a circular orbit assumption for assigning orbital parameters. For ORDEM 3.1, non-circular orbital elements were assigned using relationships that were identified between mean motion and the angle between the orbit plane and the stable Laplace plane, as well as between mean motion and eccentricity, based on breakup clouds modeled by the NASA Standard Breakup Model. This approach has yielded a high-fidelity GEO model that has been validated with data from more recent MODEST observation campaigns

ORDEM 3.1 Development Status

In this presentation we shall review NASA Orbital Debris Engineering Model (ORDEM) scope, intended use, and version history; development of the latest version, v. 3.1; provide a current development status; and discuss current deployment plans. We will also place ORDEM in context with other NASA and US models as well as the ESA MASTER model, ORDEMs closest analogue model

The Space Debris Sensor Experiment

The Space Debris Sensor (SDS) is a NASA Class 1E technology demonstration external payload aboard the International Space Station (ISS). With approximately one square meter of detection area, the SDS is attached to the European Space Agency Columbus module facing the ISS velocity vector with minimal obstruction from ISS hardware. The SDS is the first flight demonstration of the Debris Resistive/Acoustic Grid Orbital NASA-Navy Sensor (DRAGONS) technology developed and matured over 10 years by the NASA Orbital Debris Program Office (ODPO), in concert with the DRAGONS consortium, to provide information on the sub-millimeter scale orbital debris environment. The SDS demonstrated the capacity to read 4 resistive grids at 1 Hz, 40 acoustic sensors at 500 kHz, and record and downlink impact data to the ground. Observable and derived data from the SDS could provide information to models that are critical to understanding risks the small debris environment poses to spacecraft in low Earth orbit. The technology demonstrated by the SDS is a major step forward in monitoring and characterizing the space debris environment. This paper will address the technical performance of the SDS during its operational lifetime and its realization of technical and scientific goals. The SDS was intended to operate for 3 years; however, the payload incurred multiple anomalies during its operational life. Subsequently termed Anomaly #1, the first was the symptomatic loss of low data rate 1553 channel command and telemetry. The second, Anomaly #2, was loss of all low- and medium-data rate (Ethernet) telemetry. Anomaly #2 proved to be unrecoverable, leading to loss of the payload after approximately 26 days on-board the ISS. Therefore, this paper also addresses the anomalies that occurred during operation of the SDS, their attribution, and their resolution. Lessons learned are described when relevant to anomaly identification, attribution, and resolution

Utilising PRA to develop a postgraduate qualification in visual impairment studies

This article reports on the study that focused on the utilisation of a Participatory Reflection and Action (PRA) methodology in order to develop a postgraduate qualification in visual impairment studies. The broader project aims to create ways in which learners with visual impairment can be included in South African schools. In lieu of this, it has therefore come to our attention that teachers of these learners in full service schools (FSS) and special needs schools may require appropriate education and training so as to effectively work with learners with visual impairment. For our exploration, we followed a case study design and utilised PRA approach as the main data generation source in the five provinces that were involved in the study. The sample involved 255 teachers in full service and special needs schools and 50 expert stakeholders in the field of visual impairment. To most teachers, being involved in PRA-based workshops was somewhat new, thus, our study found that teachers have varying views in terms of them (teachers) being part of PRA-based workshops. Although most of them commend the process of these workshops, others feel that there could be an opportunity for improvement

The NASA Orbital Debris Engineering Model 3.1: Development, Verification, and Validation

The NASA Orbital Debris Program Office has developed the Orbital Debris Engineering Model (ORDEM) primarily as a tool for spacecraft designers and other users to understand the long-term risk of collisions with orbital debris. The newest version, ORDEM 3.1, incorporates the latest and highest fidelity datasets available to build and validate representative orbital debris populations encompassing low Earth orbit (LEO) to geosynchronous orbit (GEO) altitudes for the years 2016-2050. ORDEM 3.1 models fluxes for object sizes > 10 m within or transiting LEO and > 10 cm in GEO. The deterministic portion of the populations in ORDEM 3.1 is based on the U.S. Space Surveillance Network (SSN) catalog, which provides coverage down to approximately 10 cm in LEO and 1 m in GEO. Observational datasets from radar, in situ, and optical sources provide a foundation from which the model populations are statistically extrapolated to smaller sizes and orbit regions that are not well-covered by the SSN catalog, yet may pose the greatest threat to operational spacecraft. Objects in LEO ranging from approximately 5 mm to 10 cm are modeled using observational data from ground-based radar, namely the Haystack Ultrawideband Satellite Imaging Radar (HUSIR formerly known as Haystack). The LEO population smaller than approximately 3 mm in size is characterized based on a reanalysis of in situ data from impacts to the windows and radiators of the U.S. Space Transportation System orbiter vehicle, i.e., the Space Shuttle. Data from impacts on the Hubble Space Telescope are also used to validate the sub-millimeter model populations in LEO. Debris in GEO with sizes ranging from 10 cm to 1 m is modeled using optical measurement data from the Michigan Orbital DEbris Survey Telescope (MODEST). Specific, major debris-producing events, including the Fengyun-1C, Iridium 33, and Cosmos 2251 debris clouds, and unique populations, such as sodium-potassium droplets, have been re-examined and are modeled and added to the ORDEM environment separately. The debris environment greater than 1 mm is forecast using NASAs LEO-to- GEO ENvironment Debris model (LEGEND). Future explosions of intact objects and collisions involving objects greater than 10 cm are assessed statistically, and the NASA Standard Satellite Breakup Model is used to generate fragments from these events. Fragments smaller than 10 cm are further differentiated based on material density categories, i.e., high-, medium-, and low-density, to better characterize the potential debris risk posed to spacecraft. The future projection of the sub-millimeter environment is computed using a special small-particle degradation model where small particles are created from intact spacecraft and rocket bodies. This work discusses the development, features, and capabilities of the ORDEM 3.1 model; the ne new data analyses used to build the model populations; and sample verification and validation results

A Model for Fast Rising, Slowly Decaying Subpulses in Gamma-Ray Bursts

Gamma ray bursts (GRB's) often feature subpulses that have a distinctively asymmetric profile -- they rise quickly and decay much more slowly, while their spectrum softens slightly with observer time. It is suggested that these subpulses are caused by slow baryonic clouds embedded within a primary $\gamma$-ray beam, which scatter the $\gamma$-radiation into our line of sight as they accelerate. Good quantitative agreement is obtained with observed light curves and spectral evolution. The kinetic energy that the baryonic component of GRB jets receives from the primary $\gamma$-radiation is predicted to be about equal to the amount of $\gamma$-radiation that is scattered, consistent with observations of afterglow. Several other observational consequences are briefly discussed. The possibility is raised that the time scale of short GRB is established by radiative acceleration and/or baryon injection rather than the time scale of the central engine.Comment: Submitted to ApJ

Infusing Social Justice Advocacy into Counselor Education: Strategies and Recommendations

As the counseling profession calls counselors to act as social justice advocates, it is imperative that they are prepared for this role. This places responsibility on counselor education programs to incorporate the necessary training into existing programs. There are strategies for infusing social justice advocacy instruction throughout the existing curricula with reasonable investments of time, energy, and funds. The purpose of this article is to offer practical strategies and recommendations, grounded in critical pedagogy and supported by a growing evidence base, that can be implemented in existing counselor education programs in order to provide a strong foundation for social justice advocacy work