Yasuhiro Kawakatsu

“Furoshiki satellite” - a large membrane structure as a novel space system

Abstract We have been studying a large membrane space structure named “Furoshiki Satellite,” as a promising candidate of a future space system for those missions requiring large area in space such as solar power generation, a large communication antenna, or a large radiator. This membrane is folded in a very small volume during launch and is deployed and controlled by a set of several satellites at its corners or using centrifugal force generated by rotating the central satellite. It is expected that such a structure will reduce the weight per area of the space structure and, if the control technology is properly applied, it can be efficiently folded during launch and easily deployed after release. This paper shows the concept of Furoshiki Satellite, its applications, and its dynamics on orbit and how to control it. A nano-satellite project on demonstrate the concept of Furoshiki Satellite will also be described briefly.

The next-generation infrared astronomy mission SPICA under the new framework

We present the current status of SPICA (Space Infrared Telescope for Cosmology and Astrophysics), which is a mission optimized for mid- and far-infrared astronomy with a cryogenically cooled 3.2 m telescope. SPICA is expected to achieve high spatial resolution and unprecedented sensitivity in the mid- and far-infrared, which will enable us to address a number of key problems in present-day astronomy, ranging from the star-formation history of the universe to the formation of planets. We have carried out the “Risk Mitigation Phase” activity, in which key technologies essential to the realization of the mission have been extensively developed. Consequently, technical risks for the success of the mission have been significantly mitigated. Along with these technical activities, the international collaboration framework of SPICA had been revisited, which resulted in maintenance of SPICA as a JAXA-led mission as in the original plan but with larger contribution of ESA than that in the original plan. To enable the ESA participation, a SPICA proposal to ESA is under consideration as a medium-class mission under the framework of the ESA Cosmic Vision. The target launch year of SPICA under the new framework is FY2025.

Transfer Trajectories from the Moon to Sun–Earth Halo Orbits

H ALO orbits in the vicinity of the Sun–Earth Lagrange points (L1/L2 points) are considered as suitable locations for astronomical observatories because an object around these places can maintain the same orientation with respect to the sun and Earth, and little fuel is required for station keeping of theHalo orbit [1–7]. There have been many investigations of transfers from Earth to Halo orbits [8–14]. In fact, NASA and ESA have already launched several astronomical satellites into Halo orbits, such as ISEE-3, WMAP, and Herschel [15,16]. Recently, the Chinese lunar probe, Chang’e-2, reached the sun–Earth L2 point from the moon after completing its primary objectives. For these Halo orbit missions, the stable manifold, which is an invariant structure of a Halo orbit, is used because the insertion maneuver to the Halo orbit is not required at the cost of the time of flight [17–20]. Moreover, small Halo orbits are generally preferable from the view point of system design because the sun–probe–Earth angle becomes small. However, the stable manifold cannot be used for the direct transfer from Earth to a small Halo orbit (e.g., less than approximately 300,000 km) because the stable manifold of such small Halo orbits cannot approach Earth [14]. On the other hand, the stable manifold of the small Halo orbit via the moon could approach Earth and also increase the opportunity of the launch. Thus, there are some studies about the transfer trajectories from the moon to Halo orbits using the stable manifold. Liu [21] investigated the lunar effect for the transfer to sun–Earth L2 [22]. Wu addressed pre-Lissajous orbit insertion trajectory maneuvers of CHANG’E-2 libration point mission [22]. Xu discussed the evolution of invariant manifolds by low-thrust and lunar gravity [23]. However, the connectivity between the moon and the stable manifold of the sun–Earth system and its quantitative characteristics has not been adequately investigated. Therefore, in this study, for the availability of the stable manifold for the transfer from the moon to the sun–Earth L2 Halo orbit, the characteristic of the connecting point between the moon and the stable manifold is investigated. In addition to this, the relative velocity of the stable manifold with respect to the moon and the time of flight from themoon to theHalo orbit are also analyzed. This study may have applicability to the Demonstration and Experiment of Space Technology for INterplanetary voyage mission by the Japan Aerospace Exploration Agency, whose spacecraft will go to the sun– Earth L2 halo orbit around 2017 though the apogee altitude increases until the lunar encounter by low thrust.

Design of a Multiple Flyby Mission to the Phaethon–Geminid Complex

A B-type near-Earth asteroid, (3200) Phaethon, is the parent body of the Geminid meteor shower. Unlike most parent bodies of meteor showers, Phaethon is dynamically an asteroid with few cometary features. Asteroids (155140) 2005 UD and (225416) 1999 YC are likely fragments originating from Phaethon, collectively known as the Phaethon–Geminid complex. A mission to this group could provide key information on their origins and solve fundamental issues in thermal and dynamic evolution of comet–asteroid transition bodies. This study assesses the feasibility of a multiple flyby mission for Phaethon, 2005 UD, and 1999 YC by a small-class mission. The objective is to design a simple multiple flyby mission based on ballistic transfers combined with gravity-assisted maneuvers that fly by some or all members of the Phaethon–Geminid complex. The results show periodic launch opportunities to all three asteroids with the best case for Phaethon requiring less than 1  km/s of Earth excess velocity. No direct transfer can...

Cooled Scientific Instrument Assembly onboard SPICA

The Space Infrared Telescope for Cosmology and Astrophysics (SPICA) is a 3.2m cooled (below 6K) telescope mission which covers mid- and far-IR waveband with unprecedented sensitivity. An overview of recent design updates of the Scientific Instrument Assembly (SIA), composed of the telescope assembly and the instrument optical bench equipped with Focal Plane Instruments (FPIs) are presented. The FPI international science and engineering review is on-going to determine the FPI suite onboard SPICA: at present the mandatory instruments and functions to perform the unique science objectives of the SPICA mission are now consolidated. The final decision on the composition of the FPI suite is expected in early 2013. Through the activities in the current pre-project phase, several key technical issues which impact directly on the instruments’ performances and the science requirements and the observing efficiency have been identified, and extensive works are underway both at instrument and spacecraft level to resolve these issues and to enable the confirmation of the SPICA FPI suite.

Maintenance of Halo Orbits Under the Thrusting Constraints

This paper investigates the preliminary orbit maintenance for the next-generation infrared astronomical mission, Space InfraredTelescope forCosmology andAstrophysics, which is to be launched into the sun–Earth L2 halo orbit. Particularly, the impact of the reaction wheel unloading V on the spacecraft trajectory from the viewpoint of orbit maintenance is analyzed. In addition, the nondivergent and suppressive methods using the characteristics of the dynamical theory for unloading V are proposed and validated.

Three-Dimensional Resonant Hopping Strategies and and the Jupiter Magnetospheric Orbiter

S INCE Mariner 10’s first swingby at Venus in 1974, gravity assists have been used successfully in many missions. The missionsGalileo andCassini, and the planned Jupiter EuropaOrbiter (NASA) and Jupiter Ganymede Orbiter (ESA), implement several gravity assists connecting resonant orbits to reduce the spacecraft energy. The missions Ulysses and Cassini, and the planned Solar Orbiter (SOLO) (ESA) and Solar-C [Japan Aerospace Exploration Agency (JAXA)], use gravity assists to increase the inclination. JAXA’s planned Jupiter Magnetospheric Orbiter (JMO) is an example of amission exploring amoon system at high latitudes. JMO requires 10s of gravity assists to both reduce the apocenter and increase the inclination. Each gravity assist connects two resonant orbits, so that the entire sequence is an example of resonant hopping. The solution space of such problems is very large, andmethods are needed to explore it quickly during preliminary design. This Note studies the three-dimensional (3-D)-resonant hopping strategy in general, and it presents an automated trajectory design method. The first part of this work shows that the Tisserand constant is the main problem parameter, and it introduces the 3-D-Tisserand graph, which gives insight to the problem. Somenewanalytical formulas are used to compute fixed-altitude gravity assists connecting resonant orbits. The graph and the formulas are the first main results of the Note. The second part of this work implements the formulas in a branchand-bound algorithm. The algorithm is applied to the JMO mission design, providing almost 10,000 solutions in just a fewminutes. The algorithm and the solution space are the second main results of this work. Details are given for one particular solution that reaches 48 inclination on the Jovian equator in less than 1.5 years.

Flyby navigation and guidance experiment for interplanetary micro-spacecraft PROCYON

This paper presents the planning, flight results and lessons learned of flyby guidance experiments of interplanetary micro-spacecraft PROCYON. PROCYON is the worlds first interplanetary micro-spacecraft and was launched on 3rd December, 2014. Orbital control of interplanetary micro-spacecraft is challenging because of severe restriction and lower reliability on spacecraft system. For guidance strategy of PROCYON, we have introduced an innovative guidance strategy by two-stage stochastic programming for thrust-direction-constrained problem. Although the flight experiment has many difficulties especially on navigation, the flight result shows that we successfully demonstrate that PROCYON has been guided to the target point with objective guidance accuracy, which is within 100[km] on B-plane at 3,000,000[km] distance from the Earth. These results contributes the future flyby navigation and guidance for interplanetary micro-spacecraft, which has severe constraints and lower reliability on spacecraft system.

Orbit Transfer Optimization for Asteroid Missions Using Weighted Cost Function

This paper presents a method of trajectory optimization based on the well-known primer vector theory, which is modified to accommodate weights in the cost function. This change arises from the need of a fast and accurate analysis obtained with an indirect method that takes into account the velocity increment used for departure from the planet and, particularly for flyby missions, the disregard of the last rendezvous impulse. A detailed derivation of the weighted cost function and its gradient is presented, followed by a discussion on the values of the weights specifically for flyby and rendezvous missions. To test the optimization method, realistic test cases are selected and their results compared against a trajectory using the solution of the Lambert problem and optimization by a nonlinear programming solver. The proposed method showed a fast design of a trajectory with a midcourse impulse, which costs less than the trajectories calculated by the other two methods.

Precision pointing control for SPICA: risk mitigation phase study

SPICA (Space Infrared Telescope for Cosmology and Astrophysics) is an astronomical mission optimized for mid- and far-infrared astronomy with a 3-m class telescope which is cryogenically cooled to be less than 6 K. The SPICA mechanical cooling system is indispensable for the mission but, generates micro-vibrations which could affect to the pointing stability performances. Activities to be undertaken during a risk mitigation phase (RMP) include consolidation of micro-vibration control design for the satellite, as well as a number of breadboarding activities centered on technologies that are critical to the success of the mission. This paper presents the RMP activity results on the microvibration control design.