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On Feb. 15, 1992 the HITEN spacecraft was inserted into orbit about the Moon. HITEN was launched on 24 January 1990, by Japan's Institute for Space and Astronautic Science (ISAS) and traversed the Earth's geotail region survived two aerobraking passes in the Earth's atmosphere (March 1991), and visited the regions near the Earth-Moon.
This paper describes the outline of the telemetry scheme proposed by the Consultative Committee of Space Data Systems (CCSDS), and the on-orbit experiment which was carried out to show the applicability of the CCSDS packet telemetry scheme using the Japan's satellite Hiten in a highly elliptical orbit. The telemetry data which are generated by the instruments are packetized in Hiten and reformed to the original data in earth stations successfully. The experimental results showed that the standardized scheme is helpful in allowing for tracking cross support between organizations, and the concatenated code is quite effective to transmit data in a low C/N condition.
The Hiten mission (formerly the MUSES-A) was the first space engineering experimental satellite of the Institute of Space and Astronautical Science (ISAS) and was launched from Kagoshima Space Center (JKSC) in Japan in January 1990. After the successful insertion into a highly elliptical orbit around the Earth, the Hiten mission carried out several objectives to demonstrate space technologies for swing-by (or gravity assist) techniques and insertion of a sub-satellite into orbital space around the Moon. The results from these engineering missions have also led to follow-on missions, including aerobraking techniques and an excursion to the Lagrange points of the Earth-Moon system.
Two passes of the ISAS (Japan's Institute of Space and Astronautical Science) Hiten spacecraft through the Earth's atmosphere, at perigee altitudes of 125 km and 120 km, during Mar. 1991 marked the first aerobraking technology demonstrations for an object in cis-lunar orbit traveling at near Earth escape velocity. Prediction and control of perigee altitude to better than 1 km was desired to assure spacecraft survival. Covariance analysis provided confidence that prediction accuracy better than 200 m for support of final trim maneuver design was achievable with NASA DSN (Deep Space Network) tracking support. ISAS used orbit determination results in their decisions to cancel final trim maneuvers. Post flight reconstructions, marking the first combined use of DSN and ISAS tracking data, yielded perigee altitude solutions which agree with the near real time mission operations support predictions to better than 50 m.
This paper describes the JPL discovery of an integrated trajectory, and the tracking and orbit determination suuport provided by JPL's Deep Space Network and Multimission Navigation Team in support of the final targeting for lunar insertion.
Aerobraking phase covariance study results and preliminary joint JPL/ISAS orbit determination findings are presented. Possible explanations for differences in the JPL and ISAS perigee altitude results are discussed. Agreement between predicted and reconstructed values for the altitude and time of perigee passage attests to the accuracy of the JPL orbit solutions.
The existence of a ballistic trajectory from the Earth to orbit about the Moon was long considered to be impossible based on analysis of the three-body problem. In 1990 a ballistic trajectory from the Earth to lunar orbit was discovered while analyzing a plan to salvage the Muses A (Hiten) spacecraft. This trajectory utilized the Sun's gravity in conjunction with the Earth and Moon's gravity and was thus the first example of a practical four-body trajectory design. This paper presents a review of lunar transfer trajectories that go beyond three-body theory and the Jacobi integral. These include Hiten, Lunar A and the Genesis return trajectory from the vicinity of the Moon to Earth.It is shown that these trajectories may be analyzed by piecing together segments where three-body motion dominates.
The present concept for robotic lunar missions combines Pegasus-launched small vehicles with the weak-stability boundary (WSB) or 'ballistic capture' trajectory suggested by Belbruno (1991). The existence of the earth's WSB, as a result of a distance from the sun of about 1.5 million km, yields a transfer that is analogous to the parabolic case but in which the earth-to-moon transit time is only 3-5 months. The WSB technique has been demonstrated by the Japanase Hiten spacecraft, which reached the lunar vicinity after 5 months in transit.
This paper documents an integrated Belbruno-Miller (B-M) trajectory and its corresponding injection period. The B-M trajectories use Weak Stability Boundaries (WSB) resulting from four-body perturbative dynamics between the earth, moon, sun, and spacecraft to significantly reduce maneuver requirements for lunar transfer. It is determined that the presented nominal trajectory has a viable 4-day injection period considering maneuver constraints. The nominal B-M trajectory produces saving varying from 150 m/s to 222 m/s over traditional Hohmann means thus pointing to the practical utility of the WSB method. Energy savings are extracted at the price of extended flight time of approximately 6-months. Usefulness of this procedure was recently dramatized by the Japanese spacecraft Hiten when it arrived a the moon on October 2, 1991 following its entry into B-M trajectory on April 25, 1991.
A method is described for constructing a new type of low energy transfer trajectory from the Earth to the moon leading to ballistic capture. This is accomplished by utilizing the nonlinear Earth-moon-sun perturbations on a point mass in three dimensions. The interaction of the gravitational fields of the bodies defines transition regions in the position-velocity space where the dynamic effects on the point mass tend to balance. These are termed weak stability boundaries. The transfer is obtained by the use of trajectories connecting the weak stability boundaries. It uses approximately 18 percent less Delta-V than the Hohmann transfer to insert a spacecraft into a circular orbit about the moon. The use of this transfer has recently been demonstrated by Japan's Hiten spacecraft, which arrived at the moon on October 2, 1991. Application of the transfer method is also made to the Lunar Observer Mission.
During 1966-1976, as part of the first phase of lunar exploration, 29 manned and robotic missions placed more than 40 objects into lunar orbit. Whereas several vehicles later successfully landed on the Moon and/or returned to Earth, others were either abandoned in orbit or intentionally sent to their destruction on the lunar surface. The former now constitute a small population of lunar orbital debris; the latter, including four Lunar Orbiters and four Lunar Module ascent stages, have contributed to nearly 50 lunar sites of man's refuse. Other lunar satellites are known or suspected of having fallen from orbit. Unlike Earth satellite orbital decays and deorbits, lunar satellites impact the lunar surface unscathed by atmospheric burning or melting. Fragmentations of lunar satellites, which would produce clouds of numerous orbital debris, have not yet been detected. The return to lunar orbit in the 1990's by the Hagoromo, Hiten, Clementine, and Lunar Prospector spacecraft and plans for increased lunar exploration early in the 21st century, raise questions of how best to minimize and to dispose of lunar orbital debris. Some of the lessons learned from more than 40 years of Earth orbit exploitation can be applied to the lunar orbital environment. For the near-term, perhaps the most important of these is postmission passivation. Unique solutions, e.g., lunar equatorial dumps, may also prove attractive. However, as with Earth satellites, debris mitigation measures are most effectively adopted early in the concept and design phase, and prevention is less costly than remediation.
In 1991, the Japanese Hiten mission used a low energy transfer with a ballistic capture at the Moon which required less delta V than a standard Hohmann transfer to the Moon.
The Selenological and Engineering Explorer (SELENE), also known as Kaguya, was the second Japanese lunar orbiter spacecraft, following the Hiten probe. The spacecraft launch in September 2007 and ended in June 2009. Two sub-satellites and a suite of instruments on the Main orbiter mapped across the Moon, exploring several science objectives relating to the geologic history of the lunar surface, including new data pertaining to magnetic anomalies and GRS data with higher spatial resolution were acquired.
The DIAD beamline for Dual Imaging and Diffraction at Diamond Light Source has opted to use an industrial robot to position its Dectris Pilatus 2M CdTe diffraction detector. This setup was chosen to enable flexible positioning of the detector in a quarter-sphere around the sample position whilst reliably holding the large weight of 139 kg of detector, detector mount and cabling in a stable position. Metrology measurements showed that the detector can be positioned with a linear repeatability of <19.7 µm and a rotational repeatability of <16.3 µrad. The detector position stays stable for a 12 h period with <10.1 µm of movement for linear displacement and <3.8 µrad for rotational displacement. X-ray diffraction from calibration samples confirmed that the robot is sufficiently stable to resolve lattice d-spacings within the instrumental broadening given by detector position and beam divergence.
Abstract not provided
The true identity of the protein found in the crystals reported by Bondoc et al. [(2019), Acta Cryst. F75, 646–651] is given.
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Plasma etching is an essential semiconductor manufacturing technology required to enable the current microelectronics industry. Along with lithographic patterning, thin-film formation methods, and others, plasma etching has dynamically evolved to meet the exponentially growing demands of the microelectronics industry that enables modern society. At this time, plasma etching faces a period of unprecedented changes owing to numerous factors, including aggressive transition to three-dimensional (3D) device architectures, process precision approaching atomic-scale critical dimensions, introduction of new materials, fundamental silicon device limits, and parallel evolution of post-CMOS approaches. The vast growth of the microelectronics industry has emphasized its role in addressing major societal challenges, including questions on the sustainability of the associated energy use, semiconductor manufacturing related emissions of greenhouse gases, and others. The goal of this article is to help both define the challenges for plasma etching and point out effective plasma etching technology options that may play essential roles in defining microelectronics manufacturing in the future. The challenges are accompanied by significant new opportunities, including integrating experiments with various computational approaches such as machine learning/artificial intelligence and progress in computational approaches, including the realization of digital twins of physical etch chambers through hybrid/coupled models. These prospects can enable innovative solutions to problems that were not available during the past 50 years of plasma etch development in the microelectronics industry. To elaborate on these perspectives, the present article brings together the views of various experts on the different topics that will shape plasma etching for microelectronics manufacturing of the future.