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DECIGO (DECi-hertz Interferometer Gravitational wave Observatory) is the planned Japanese space gravitational wave antenna, aiming to detect gravitational waves from astrophysically and cosmologically significant sources mainly between 0.1 Hz and 10 Hz and thus to open a new window for gravitational wave astronomy and for the universe. DECIGO will consists of three drag-free spacecraft arranged in an equilateral triangle with 1000 km arm lengths whose relative displacements are measured by a differential Fabry-Perot interferometer, and four units of triangular Fabry-Perot interferometers are arranged on heliocentric orbit around the sun. DECIGO is vary ambitious mission, we plan to launch DECIGO in era of 2030s after precursor satellite mission, B-DECIGO. B-DECIGO is essentially smaller version of DECIGO: B-DECIGO consists of three spacecraft arranged in an triangle with 100 km arm lengths orbiting 2000 km above the surface of the earth. It is hoped that the launch date will be late 2020s for the present..

The JUpiter Icy Moon Explorer mission (JUICE) was designed to investigate Jupiter, its environment and its icy moons with at least one Europa flyby, a high inclination phase around Jupiter and a 280 days long near polar orbital phase around Ganymede, with 130 days on a low circular orbit. The goal of the JUICE mission analysis consisted in implementing these mission elements within a tight mass and radiation budget. A shift in the nominal launch date from June 2022 to September 2022 then April 2023 resulted in an arrival date at Jupiter in July 2031, close to equinox, so that the duration of eclipses by Jupiter became a major issue. A mission scheme meeting the requirements was designed using innovative approaches such as a double swing-by of the Moon and the Earth and a low energy endgame targeting a grazing Callisto flyby then grazing Ganymede encounters. Thanks to a near optimum launch date and launcher performance with full tanks, the post-launch Delta-V margins (150 m/s) made it possible to re-instate a 200 km circular orbital phase at the end of the nominal mission as planned in the mission proposal. The remaining Delta-V margin (55 m/s) and that expected from clean-up costs lower than allocated make it possible, while keeping adequate margins for contingencies, to consider significant improvements of the baseline mission scheme, in particular a higher maximum inclination during the tour and an inclination on the 200 km orbit close to Sun-synchronous, so that a long extended mission can be considered.

The Moon is the only celestial body that human beings have visited. The design of the Earth-Moon transfer orbits is a critical issue in lunar exploration missions. In the 21st century, new lunar missions including the construction of the lunar space station, the permanent lunar base, and the Earth-Moon transportation network have been proposed, requiring low-cost, expansive launch windows and a fixed arrival epoch for any launch date within the launch window. The low-energy and low-thrust transfers are promising strategies to satisfy the demands. This review provides a detailed landscape of Earth-Moon transfer trajectory design processes, from the traditional patched conic to the state-of-the-art low-energy and low-thrust methods. Essential mechanisms of the various utilized dynamic models and the characteristics of the different design methods are discussed in hopes of helping readers grasp the basic overview of the current Earth-Moon transfer orbit design methods and a deep academic background is unnecessary for the context understanding.

Previous research in software product development used the lens of escalation of commitment to study the problem of adhering to original product launch dates and suggested that decisions related to launching new products can be particularly prone to escalation of commitment because they involve a high level of uncertainty and large financial stakes. In this study, we propose perspective-taking as a de-escalation tactic to reduce product managers' commitment to the original product launch date when faced with severe software defects. In two laboratory experiments, we found that when participants took the perspective of product users who might be negatively affected by the launch of a defective software product, their commitment de-escalated more than when they took a shareholder's perspective. We also found that anticipated guilt about launching the product as scheduled mediated the relationship between perspective-taking and de-escalation. In addition, one of the experiments involved severe consequences associated with the software defects; in that case, we found that the mediation effect of anticipated guilt was moderated by the product managers' customer orientation. This study makes a theoretical contribution to the literature of de-escalation of commitment by proposing perspective-taking as a new de-escalation tactic, and by demonstrating the affect-based mechanism of perspective-taking that operates through anticipated guilt. While practitioners may use perspective-taking as an effective tactic in reducing commitment to launching a defective software product, our findings highlight the importance of selecting the appropriate target perspective.

During the early post-launch phase of the Landsat 9 mission, the Landsat 8 and 9 mission teams conducted a successful under-fly of Landsat 8 by Landsat 9, allowing for the near-simultaneous data collection of common Earth targets by the on-board sensors for cross-calibration. This effort, coordinated by the Landsat Calibration and Validation team, required contributions from various entities across National Aeronautics and Space Administration and U.S. Geological Survey such as Flight Dynamics, Systems, Mission Planning, and Flight Operations teams, beginning about 18 months prior to launch. Plans existed to allow this under-fly for any possible launch date of Landsat 9. This included 16 ascent plans and 16 data acquisition plans, one for every day of the Landsat orbital repeat period, with a minimum of 5 days of useful coverage overlap between the sensors. After the Landsat 9 launch, the plan executed, and led to the acquisition of over 2000 partial to full overlapping scene pairs. Although containing less than the expected number of scenes, this dataset was larger than previous Landsat mission under-fly efforts and more than sufficient for performing cross-calibration of the Landsat 8 and Landsat 9 sensors. The details of the planning process and execution of this under-fly are presented.

The Visible Infrared Imaging Radiometer Suite (VIIRS) instruments on-board the Suomi National Polar-orbiting Partnership (S-NPP), National Oceanic and Atmospheric Administration 20 (NOAA-20) and Joint Polar Satellite System (JPSS-2) spacecraft, with launch dates of October 2011, November 2017 and late 2022, respectively, have polarization sensitivity that affects the at-aperture radiometric Sensor Data Record (SDR) calibration in the Visible Near InfraRed (VNIR) spectral region. These SDRs are used as inputs into the VIIRS atmospheric, land, and water Environmental Data Records (EDRs) that are integral to climate and weather applications. Pre-launch characterization of the VIIRS polarization sensitivity was performed that provides an SDR radiance correction factor to enable high fidelity EDR products for the user community. The pre-launch polarization sensitivity used an external source that consisted of a 100 cm diameter Spherical Integrating Source (SIS) in combination with several sheet polarizers. These sheet polarizers were illuminated by the SIS and viewed by the VIIRS instrument. The sheet was then rotated to measure the variation in the VIIRS response relative to the at-aperture polarization orientation. There are sensor requirements that define the maximum allowed polarization amplitude to be below 2.5–3.0% depending on the band and have an uncertainty in both amplitude and phase of less than 0.5%. The pre-launch data analysis evaluated the VIIRS response through the rotating sheet polarizer to quantify each VNIR bands polarization amplitude, phase, and uncertainty. These parameters were compared with the sensor requirements and used to create on-orbit Look-Up Tables (LUTs) for EDR ground processing. The results of the analysis showed that all bands met the uncertainty requirement of 0.5%, but band M1 failed the 3% polarization amplitude requirement. A root-cause analysis identified the optical element responsible for the non-compliance and has been modified for JPSS-3 and -4 builds. The large polarization amplitudes observed in the NOAA-20 VIIRS build, for bands M1-M4, are greatly reduced for JPSS-2 VIIRS. This improved polarization performance was due to modifications to the band M1-M4 bandpass filters between these sensor builds.

Metop is the space segment of the EUMETSAT Polar System (EPS), which provides real-time data to several European meteorological services as well as to the National Oceanic and Atmospheric Administration (NOAA) and other international agencies. The third Metop satellite, Metop-C, was launched on 7 November 2018 and shall enter in operations in few months, once the on-going commissioning of the meteorological products is completed. Each Metop satellite was designed to operate at least five years. A sequential deployment of the satellites was foreseen to achieve the target mission duration of 15 years, replacing an old one at end of life with a newer one; thanks to the excellent performances of the launchers and of the platform itself, and to continuous improvements to the fuel management, it was possible to extend the operational life of each satellite by a factor of three, still maintaining enough fuel to perform safe de-orbiting operations (foreseen for Metop-A, launched in 2006, at the end of 2021). This provided the opportunity to develop in 2012 (after Metop-B launch) dual-satellite products, which now, with the arrival of Metop-C, can evolve to tri-satellite; several decisions, concerning the selection of launch date and time as well as commissioning and operational locations, had to be been taken to achieve the target configuration; the analyses leading to these decisions are discussed here.

If a space-faring civilization embarks on a program to send probes to interstellar destinations, the first probe to arrive at such a destination is not likely to be one of the earliest probes, but one of much more advanced capability. This conclusion is based on a scenario in which an extraterrestrial civilization (ETC) embarks upon an interstellar program during which it launches increasingly sophisticated probes whose departure speed increases as a function of time throughout the program. Two back-of-the-envelope models are considered: one in which the launch velocity of an outgoing vehicle increases linearly with the time of launch, and a second in which the increase is exponential with launch date. In this paper consideration is directed to an hypothesized probe arriving within the Solar System from a non-terrestrial civilization. Within the above scenarios, a first-encounter probe will be one that was launched well after the initiation of an interstellar program by an ETC. Consequently, such a probe would be the product of a relatively advanced phase of that ETC's technology. The more distant the site from which an ETC is launching probes, the greater will be the technology gap between a first-encounter probe and terrestrial technology. One possible ramification may pertain to interpreting the nature of Unidentified Aerial Phenomena (UAP). Are flight characteristics of any UAP singular enough as to be consistent with an origin from a distant ETC?

The objective of this paper is to find an empirical hyperspectral absolute calibration model using Libya 4 pseudo invariant calibration site (PICS). The approach involves using the Landsat 8 (L8) Operational Land Imager (OLI) as the reference radiometer and using Earth Observing One (EO-1) Hyperion, with a spectral resolution of 10 nm as a hyperspectral source. This model utilizes data from a region of interest (ROI) in an “optimal region” of 3% temporal, spatial, and spectral stability within the Libya 4 PICS. It uses an improved, simple, empirical, hyperspectral Bidirectional Reflectance Distribution function (BRDF) model accounting for four angles: solar zenith and azimuth, and view zenith and azimuth angles. This model can perform absolute calibration in 1 nm spectral resolution by predicting TOA reflectance in all existing spectral bands of the sensors. The resultant model was validated with image data acquired from satellite sensors such as Landsat 7, Sentinel 2A, and Sentinel 2B, Terra MODIS, Aqua MODIS, from their launch date to 2020. These satellite sensors differ in terms of the width of their spectral bandpass, overpass time, off-nadir viewing capabilities, spatial resolution, and temporal revisit time, etc. The result demonstrates the efficacy of the proposed model has an accuracy of the order of 3% with a precision of about 3% for the nadir viewing sensors (with view zenith angle up to 5°) used in the study. For the off-nadir viewing satellites with view zenith angle up to 20°, it can have an estimated accuracy of 6% and precision of 4%.