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Author name code: sako
ADS astronomy entries on 2022-09-14
author:"Sako, Nobuharu"
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Title: Constraining hot plasma in a non-flaring solar active region
with FOXSI hard X-ray observations
Authors: Ishikawa, Shin-nosuke; Glesener, Lindsay; Christe, Steven;
Ishibashi, Kazunori; Brooks, David H.; Williams, David R.; Shimojo,
Masumi; Sako, Nobuharu; Krucker, Säm
2014PASJ...66S..15I Altcode: 2015arXiv150905288I; 2014PASJ..tmp..102I
We present new constraints on the high-temperature emission measure
of a non-flaring solar active region using observations from the
recently flown Focusing Optics X-ray Solar Imager (FOXSI) sounding
rocket payload. FOXSI has performed the first focused hard X-ray
(HXR) observation of the Sun in its first successful flight on 2012
November 2. Focusing optics, combined with small strip detectors,
enable high-sensitivity observations with respect to previous
indirect imagers. This capability, along with the sensitivity of
the HXR regime to high-temperature emission, offers the potential
to better characterize high-temperature plasma in the corona as
predicted by nanoflare heating models. We present a joint analysis of
the differential emission measure (DEM) of active region 11602 using
coordinated observations by FOXSI, Hinode/XRT, and Hinode/EIS. The
Hinode-derived DEM predicts significant emission measure between
1 MK and 3 MK, with a peak in the DEM predicted at 2.0-2.5 MK. The
combined XRT and EIS DEM also shows emission from a smaller population
of plasma above 8 MK. This is contradicted by FOXSI observations that
significantly constrain emission above 8 MK. This suggests that the
Hinode DEM analysis has larger uncertainties at higher temperatures and
that > 8 MK plasma above an emission measure of 3 × 10<SUP>44</SUP>
cm<SUP>-3</SUP> is excluded in this active region.
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Title: The Three-dimensional Analysis of Hinode Polar Jets using
Images from LASCO C2, the Stereo COR2 Coronagraphs, and SMEI
Authors: Yu, H. -S.; Jackson, B. V.; Buffington, A.; Hick, P. P.;
Shimojo, M.; Sako, N.
2014ApJ...784..166Y Altcode:
Images recorded by the X-ray Telescope on board the Hinode spacecraft
are used to provide high-cadence observations of solar jetting
activity. A selection of the brightest of these polar jets shows
a positive correlation with high-speed responses traced into the
interplanetary medium. LASCO C2 and STEREO COR2 coronagraph images
measure the coronal response to some of the largest jets, and also the
nearby background solar wind velocity, thereby giving a determination
of their speeds that we compare with Hinode observations. When using
the full Solar Mass Ejection Imager (SMEI) data set, we track these
same high-speed solar jet responses into the inner heliosphere and from
these analyses determine their mass, flow energies, and the extent to
which they retain their identity at large solar distances.
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Title: A Statistical Study of Coronal Active Events in the North
Polar Region
Authors: Sako, Nobuharu; Shimojo, Masumi; Watanabe, Tetsuya; Sekii,
Takashi
2013ApJ...775...22S Altcode:
In order to study the relationship between characteristics of polar
coronal active events and the magnetic environment in which such events
take place, we analyze 526 X-ray jets and 1256 transient brightenings
in the polar regions and in regions around the equatorial limbs. We
calculate the occurrence rates of these polar coronal active events
as a function of distance from the boundary of coronal holes, and
find that most events in the polar quiet regions occur adjacent to
and equatorward of the coronal hole boundaries, while events in the
polar coronal holes occur uniformly within them. Based primarily on
the background intensity, we define three categories of regions that
produce activity: polar coronal holes, coronal hole boundary regions,
and polar quiet regions. We then investigate the properties of the
events produced in these regions. We find no significant differences
in their characteristics, for example, length and lifetime, but there
are differences in the occurrence rates. The mean occurrence rate of
X-ray jets around the boundaries of coronal holes is higher than that
in the polar quiet regions, equatorial quiet regions, and polar coronal
holes. Furthermore, the mean occurrence rate of transient brightenings
is also higher in these regions. We make comparison with the occurrence
rates of emerging and canceling magnetic fields in the photosphere
reported in previous studies, and find that they do not agree with
the occurrence rates of transient brightenings found in this study.
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Title: Polar Field Reversal Observations with Hinode
Authors: Shiota, D.; Tsuneta, S.; Shimojo, M.; Sako, N.; Orozco Suarez,
D.; Ishikawa, R.
2012AGUFMSH13C2274S Altcode:
We have been monitoring yearly variation in the Sun's polar magnetic
fields with the Solar Optical Telescope aboard Hinode to record their
evolution and expected reversal near the solar maximum. All magnetic
patches in the magnetic flux maps are automatically identified to obtain
the number density and magnetic flux density as a function of the total
magnetic flux per patch. The detected magnetic flux per patch ranges
over four orders of magnitude (10^15 -- 10^20 Mx). The higher end of
the magnetic flux in the polar regions is about one order of magnitude
larger than that of the quiet Sun, and nearly that of pores. Almost
all large patches ( > 10^18 Mx) have the same polarity, while
smaller patches have a fair balance of both polarities. The polarity
of the polar region as a whole is consequently determined only by the
large magnetic concentrations. A clear decrease in the net flux of
the polar region is detected in the slow rising phase of the current
solar cycle. The decrease is more rapid in the north polar region than
in the south. The decrease in the net flux is caused by a decrease in
the number and size of the large flux concentrations as well as the
appearance of patches with opposite polarity at lower latitudes. In
contrast, we do not see temporal change in the magnetic flux associated
with the smaller patches ( < 10^18 Mx) and that of the horizontal
magnetic fields during the years 2008--2012.
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Title: Statistical Study of X-ray Jets in the Polar Region
Authors: Sako, N.; Shimojo, M.; Kitabayashi, T.
2012ASPC..454..153S Altcode:
We detected 848 polar X-ray jets occurred in the north polar region,
and investigated the characteristics of the jets statistically. The
470 jets of them occurred in the coronal hole. The occurrence
rate of the jets in the coronal hole and the quiet region are
5.04×10<SUP>-12</SUP> jets/hr/km<SUP>2</SUP> and 7.66×10<SUP>-12</SUP>
jets/hr/km<SUP>2</SUP>, respectively. We derived five parameters
of the polar X-ray jets. The averaged values of the parameters are
2.91×10<SUP>4</SUP> km for the maximum length, 4.42×10<SUP>3</SUP>
km for the width, 608 sec for the lifetime and 180 km/sec for the
apparent velocity. If we assume that the frequency distribution of
the lifetime and the footpoint flare show the power-law distributions,
and the index is -1.80 ± 0.20 in the coronal hole and -1.84 ± 0.17
in the quiet region. The frequency distribution is steeper than that
of the previous works.
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Title: Polar Field Reversal Observations with Hinode
Authors: Shiota, D.; Tsuneta, S.; Shimojo, M.; Sako, N.; Orozco
Suárez, D.; Ishikawa, R.
2012ApJ...753..157S Altcode: 2012arXiv1205.2154S
We have been monitoring yearly variation in the Sun's polar magnetic
fields with the Solar Optical Telescope aboard Hinode to record their
evolution and expected reversal near the solar maximum. All magnetic
patches in the magnetic flux maps are automatically identified to
obtain the number density and magnetic flux density as a function of
the total magnetic flux per patch. The detected magnetic flux per patch
ranges over four orders of magnitude (10<SUP>15</SUP>-10<SUP>20</SUP>
Mx). The higher end of the magnetic flux in the polar regions is about
one order of magnitude larger than that of the quiet Sun, and nearly
that of pores. Almost all large patches (>=10<SUP>18</SUP> Mx) have
the same polarity, while smaller patches have a fair balance of both
polarities. The polarity of the polar region as a whole is consequently
determined only by the large magnetic concentrations. A clear decrease
in the net flux of the polar region is detected in the slow rising phase
of the current solar cycle. The decrease is more rapid in the north
polar region than in the south. The decrease in the net flux is caused
by a decrease in the number and size of the large flux concentrations
as well as the appearance of patches with opposite polarity at lower
latitudes. In contrast, we do not see temporal change in the magnetic
flux associated with the smaller patches (<10<SUP>18</SUP> Mx)
and that of the horizontal magnetic fields during the years 2008-2012.
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Title: A preliminary study of the HOP-187 jet analysis
Authors: Jackson, B.; Yu, H. -S.; Buffington, A.; Clover, J.; Shimojo,
M.; Sako, N.
2012decs.confE.111J Altcode:
The Hinode Observing Proposal (HOP)-187, "Tracking X-ray Jets from
the Solar Surface to Interplanetary Space" (Jackson and Shimojo,
2011) was carried out successfully during the summer of 2011. On
two occasions (00-06 UT 17 June, 2011, and 00-08 UT 22 August 2011)
XRT observations were run at a higher cadence over the south polar
region in conjunction with LASCO C2 observations that also provided
an enhanced 5-minute cadence and 100-sec exposures from this
instrument. This campaign effort was joined by the NASA SDO AIA,
the Solar TErrestrial RElations Observatory (STEREO) Coronagraph
(COR II) and Heliospheric Imagers (HI's), ground-based interplanetary
scintillation (IPS) observations from the Solar Terrestrial Environment
Laboratory (STELab) and Ootacamund (Ooty), India, and finally data
from the Solar Mass Ejection Imager (SMEI). In this data analysis,
as in previous campaign-mode operations of the Hinode XRT instrument,
we find a positive correlation between the brightest of the polar jets
and a high-speed response traced into the interplanetary medium. Here,
we report on the preliminary measurements of the jet responses that
were observed during this successful HOP-187 campaign.
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Title: New loss-process for accelerated electrons around the flare
loop-top?
Authors: Goto, T.; Masuda, S.; Miyoshi, Y.; Minoshima, T.; Nishimura,
Y.; Anan, T.; Sako, N.; Matsui, Y.
2011AGUFMSH41A1895G Altcode:
Nonthermal emissions - hard X-rays, gamma-rays and microwave
- from loop-top sources of solar flares are related to
acceleration/transportation processes of electrons under the magnetic
reconnection point. So in order to understand these processes, it is
important to study temporal and spatial variations of loop-top sources
by using data of multiwavelength observation. We studied an M3.7 class
flare which occurred on Jul. 27, 2005. This flare took place behind the
limb. So we can see only loop-top source itself without any effects of
emissions from the footpoints. We used two frequency data of Nobeyama
Radio Heliograph (NoRH; 17GHz and 34GHz, both of them are emitted by
MeV electrons). According to a simulation (Minoshima et al. 2011),
we expected that loop-top microwave source of 34GHz is located lower
than that of 17GHz, because higher energy electrons which emit 34GHz
microwave can reach to a lower altitude with less collisions during
the transportation. But we got a result that the loop-top source of
34GHz was located higher than that of 17GHz during the whole period
of the flare. This result might suggest that additional loss process
selectively works for the higher-energy electrons emitting 34GHz. To
know whether such a process really exists, we investigated decay
time-scale of light curve in some emission regions. At a low-altitude
region, the decay time-scale is explainable in terms of Coulomb
scattering. But at a high-altitude region, higher-energy electrons
which emit 34GHz microwave decrease faster than expected by Coulomb
scattering. So this suggests that there are some different scattering
processes at a high-altitude region. However, still the decay time-scale
of 34GHz is a little longer than that of 17GHz, we cannot explain the
height difference between the 17GHz and 34GHz loop-top sources in only
scattering processes. We need to consider the spectral variation of
accelerated /injected electrons like so-called soft-hard-soft variation.
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Title: Observations of Polar-Region Jets and Their Manifestations
in the Solar Wind
Authors: Jackson, Bernard V.; Clover, John M.; Hick, P. Paul;
Buffington, Andrew; Linford, John C.; Shimojo, Masumi; Sako, Nobuharu
2011shin.confE.170J Altcode:
High-cadence images taken by the X-Ray Telescope (XRT) aboard Hinode
(Solar B), have shown that X-ray jets occur at very high frequency over
the polar regions of the Sun. Only the brightest of these explosive
events had been previously observed. It is possible that Alfven waves
generated by jets contribute greatly to the acceleration of the solar
wind; each jet provides a conduit for Alfven waves that add significant
energy to the corona by spreading outward from these localized areas
on the Sun. Here we explore the manifestations of the jet response in
the solar wind using observations from Hinode, the LASCO coronagraph,
and from 3D tomographic observations at greater heights above the
Sun. We attempt to quantify the jet response in the interplanetary
medium from these measurements, and to explore the diminution of this
response with solar radius.
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Title: Statistical study of the polar X-ray jets
Authors: Sako, Nobuharu; Shimojo, Masumi; Kitabayashi, Teruyuki
2010cosp...38.2843S Altcode: 2010cosp.meet.2843S
The X-Ray Telescope(XRT) abroad Hinode had revealed that X-ray jets in
the polar region occur at the high frequency. Savcheva et al. (2007)
studied 104 X-ray jets occurred around the south pole and reported
the parameters of the jets. However, their study included only the
X-ray jets that occurred in the coronal hole. In order to reveal the
properties of the polar X-ray jets in not only the coronal hole but also
the quiet region, we detected 870 polar X-ray jets occurred around the
north pole, and investigated the jets statistically. The 470 jets in
the 848 events occurred in the coronal hole. The occurrence rate of the
jets in the coronal hole and the quiet sun is 5.04×10-12 jets/hr/km2
and 7.66×10-12 jets/hr/km2 , respectively. It shows that the quiet
region is more productive of X-ray jets than the coronal hole. We
derived five parameters of the polar X-ray jets, and the average of
the parameters are 2.91×104 km for the maximum length, 4.42×103 km
for the width, and 180 km/sec for the apparent velocity. The lifetime
and length scale of the jets in this result is smaller than that in
Savcheva et al. (2007). The reason for these differences is that we
could detect smaller jets than the previous work because we used not
only X-ray intensity images but also the running difference images for
detecting the jets. We derived also the frequency distributions of the
parameters and found thatthe frequency distributions of the lifetime
and the X-ray intensity of the footpoint flare show the power-raw
distribution. The power-law index of the lifetime is -4.22±0.36,
and it is smaller than the index(-1.2) derived from the jets that
occurred near the active regions(Shimojo et al. 1996). The difference
indicates that the occurrence rate of the polar X-ray jets with short
lifetime is larger than that of the X-ray jets that occurred near active
regions.On the other hand, the power-raw index of the X-ray intensity
of the footpoint flare is -2.04±0.27. The index is smaller than that
of the X-ray jets near the active regions(Shimojo et al. 1996).
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Title: A Star Image Extractor for the Nano-JASMINE satellite
Authors: Yamauchi, M.; Gouda, N.; Kobayashi, Y.; Tsujimoto, T.; Yano,
T.; Suganuma, M.; Yamada, Y.; Nakasuka, S.; Sako, N.
2008IAUS..248..294Y Altcode:
We have developped a software of Star-Image-Extractor (SIE) which works
as the on-board real-time image processor. It detects and extracts only
the object data from raw image data. SIE has two functions: reducing
image data and providing data for the satellite's high accuracy attitude
control system.
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Title: The current status of the Nano-JASMINE project
Authors: Kobayashi, Y.; Gouda, N.; Yano, T.; Suganuma, M.; Yamauchi,
M.; Yamada, Y.; Sako, N.; Nakasuka, S.
2008IAUS..248..270K Altcode:
Nano-JASMINE is a nano-size astrometry satellite that will carry
out astrometry measurements of nearby bright stars for more than
one year. This will enable us to detect annual parallaxes of stars
within 300 pc from the Sun. We expect the satellite to be launched as
a piggy-back system as early as in 2009 into a Sun synchronized orbit
at the altitude between 500 and 800 km. Being equipped with a beam
combiner, the satellite has a capability to observe two different
fields simultaneously and will be able to carry out HIPPARCOS-type
observations along great circles. A 5 cm all aluminum made reflecting
telescope with a aluminum beam combiner is developed. Using the on-board
CCD controller, experiments with a real star have been executed. A
communication band width is insufficient to transfer all imaging data,
hence, we developed an onboard data processing system that extracts
stellar image data from vast amount of imaging data. A newly developed
2K × 1K fully-depleted CCD will be used for the mission. It will work
in the time delayed integration(TDI) mode. The bus system has been
designed with special consideration of the following two points. Those
are the thermal stabilization of the telescope and the accuracy of the
altitude control. The former is essential to achieve high astrometric
accuracies, on the order of 1 mas. Therefore relative angle of the
beam combiner must be stable within 1 mas. A 3-axes control of the
satellite will be realized by using fiber gyro and triaxial reaction
wheel system and careful treatment of various disturbing forces.
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Title: A very small astrometry satellite mission: Nano-JASMINE
Authors: Kobayashi, Y.; Gouda, G.; Tsujimoto, T.; Yano, T.; Suganuma,
M.; Yamauchi, M.; Takato, N.; Miyazaki, S.; Yamada, Y.; Sako, N.;
Nakasuka, S.
2006IAUJD..13E..32K Altcode:
The current status of the nano-JASMINE project is
presented. Nano-JASMINE--a very small satellite weighing less than
10 kg--aims to carry out astrometry measurements of nearby bright
stars. This satellite adopts the same observation technique that
was used by the HIPPARCOS satellite. In this technique, simultaneous
measurements in two different fields of view separated by an angle
that is greater than 90 degrees are carried out; these measurements
are performed in the course of continuous scanning observations of
the entire sky. This technique enables us to distinguish between an
irregularity in the spin velocity and the distribution of stellar
positions. There is a major technical difference between the
nano-JASMINE and the HIPPARCOS satellites--the utilization of a CCD
sensor in nano-JASMINE that makes it possible to achieve an astrometry
accuracy comparable to that achieved by HIPPARCOS by using an extremely
small telescope. We developed a prototype of the observation system and
evaluated its performance. The telescope (5cm) including a beam combiner
composed entirely of aluminum. The telescope is based on the standard
Ritchey-Chretien optical system and has a composite f-ratio of 33
that enables the matching of the Airy disk size to three times the CCD
pixel size of 15um. A full depletion CCD will be used in the time delay
integration (TDI) mode in order to efficiently survey the whole sky in
wavelengths including the near infrared. The nano-JASMINE satellite is
being developed as a piggyback system and is [S: scheduled for launch
in 2008. We expect the satellite to measure the position and proper
motion of bright stars (mz< 8.3) with an accuracy of 1 mas, this
is comparable to the accuracy achieved with the HIPPARCOS satellite.
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Title: JASMINE Simulator
Authors: Yamada, Y.; Gouda, N.; Yano, T.; Kobayashi, Y.; Suganuma,
M.; Tsujimoto, T.; Sako, N.; Hatsutori, Y.; Tanaka, T.
2006IAUJD..13E..31Y Altcode:
We explain simulation tools in JASMINE project (JASMINE simulator). The
JASMINE project stands at the stage where its basic design will be
determined in a few years. Then it is very important to simulate
the data stream generated by astrometric fields at JASMINE in order
to support investigations of error budgets, sampling strategy, data
compression, data analysis, scientific performances, etc. Of course,
component simulations are needed, but total simulations which include
all components from observation target to satellite system are also
very important. We find that new software technologies, such as Object
Oriented (OO) methodologies are ideal tools for the simulation system
of JASMINE (the JASMINE simulator). The simulation system should
include all objects in JASMINE such as observation techniques, models
of instruments and bus design, orbit, data transfer, data analysis
etc. in order to resolve all issues which can be expected beforehand
and make it easy to cope with some unexpected problems which might
occur during the mission of JASMINE. So, the JASMINE Simulator is
designed as handling events such as photons from astronomical objects,
control signals for devices, disturbances for satellite attitude, by
instruments such as mirrors and detectors, successively. The simulator
is also applied to the technical demonstration "Nano-JASMINE". The
accuracy of ordinary sensor is not enough for initial phase attitude
control. Mission instruments may be a good sensor for this purpose. The
problem of attitude control in initial phase is a good example of
this software because the problem is closely related to both mission
instruments and satellite bus systems.
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Title: JASMINE-Astrometric Map of the Galactic Bulge-
Authors: Gouda, N.; Kobayashi, Y.; Yamada, Y.; Yano, T.; Tsujimoto,
T.; Suganuma, M.; Niwa, Y.; Yamauchi, M.; Kawakatsu, Y.; Matsuhara,
H.; Moda, A.; Tsuiki, A.; Utashima, M.; Ogawa, A.; Sako, N.
2006IAUJD..13E..30G Altcode:
We introduce a Japanese plan of infrared(z-band:0.9μm) space astrometry
(JASMINE-project). JASMINE is the satellite (Japan Astrometry Satellite
Mission for INfrared Exploration) which will measure the distances and
apparent motions of stars around the center of the Milky Way with yet
unprecedented precision. It will measure parallaxes, positions with
the accuracy of 10 micro-arcsec and proper motions with the accuracy
of 4 micro-arcsec/year for stars brighter than z=14mag. JASMINE can
observe about ten million stars belonging to the bulge components of
our Galaxy, which are hidden by the interstellar dust extinction in
optical bands. Number of stars with sigma/pi <0.1 in the direction
of the Galactic central bulge is about 1000 times larger than those
observed in optical bands, where pi is a parallax and sigma is an
error of the parallax. With the completely new "map of the bulge in the
Milky Way", it is expected that many new exciting scientific results
will be obtained in various fields of astronomy. We will introduce
some scientific topics which will be obtained by JASMINE. Presently,
JASMINE is in a development phase, with a target launch date around
2015. We adopt the following instrument design of JASMINE in order to
get the accurate positions of many stars. We adopt a 3-mirrors optical
system (modified Korsch system) with a primary mirror of 0.75m. On
the astro-focal plane, we put dozens of new type of CCDs for z-band
to get a wide field of view. The consideration of overall system(bus)
design is now going on in cooperation with Japan Aerospace Exploration
Agency (JAXA). The introduction of JASMINE and the present status of
the project will be shown in the presentation.
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Title: JASMINE-astrometric map of the galactic bulge .
Authors: Gouda, N.; Kobayashi, Y.; Yamada, Y.; Yano, T.; Tsujimoto,
T.; Suganuma, M.; Niwa, Y.; Yamauchi, M.; Kawakatsu, Y.; Matsuhara,
H.; Noda, A.; Tsuiki, A.; Utashima, M.; Ogawa, A.; Sako, N.; JASMINE
working Group
2006MmSAI..77.1185G Altcode:
We introduce a Japanese plan of infrared (z-band:0.9mu m) space
astrometry(JASMINE-project). JASMINE is the satellite (Japan Astrometry
Satellite Mission for INfrared Exploration) which will measure
distances and apparent motions of stars around the center of the Milky
Way with yet unprecedented precision. It will measure parallaxes with
the accuracy of 10 micro-arcsec and proper motions with the accuracy
of 4 micro-arcsec/year for stars brighter than z=14mag. JASMINE can
observe about ten million stars belonging to the bulge components of
our Galaxy, which are hidden by the interstellar dust extinction in
optical bands. Number of stars with sigma /pi <0.1 in the direction
of the Galactic central bulge is about 1000 times larger than those
observed in optical bands, where pi is a parallax and sigma is an
error of the parallax. With the completely new map of the bulge in the
Milky Way it is expected that many new exciting scientific results
will be obtained in various fields of astronomy. We will introduce
some scientific topics which will be obtained by JASMINE. Presently,
JASMINE is in a development phase, with a target launch date around
2015. We adopt the following instrument design of JASMINE in order to
get the accurate positions of many stars. We adopt a 3-mirrors optical
system (modified Korsch system) with a primary mirror of 0.75m. On
the astro-focal plane, we put dozens of new type of CCDs for z-band
to get a wide field of view. JASMINE mission takes a frames-link
method which can be applied for the survey of the Galactic bulge,
as a observing strategy. The consideration of overall system (bus)
design is now going on in cooperation with Japan Aerospace Exploration
Agency (JAXA). The introduction of JASMINE and the present status of
the project will be shown in the presentation.
---------------------------------------------------------
Title: JASMINE simulator
Authors: Yamada, Y.; Gouda, N.; Yano, T.; Sako, N.; Hatsutori, Y.;
Tanaka, T.; Yamauchi, M.
2006MmSAI..77.1190Y Altcode:
We explain simulation tools in JASMINE project(JASMINE simulator). The
JASMINE project stands at the stage where its basic design will be
determined in a few years. Then it is very important to simulate
the data stream generated by astrometric fields at JASMINE in order
to support investigations of error budgets, sampling strategy, data
compression, data analysis, scientific performances, etc. Of course,
component simulations are needed, but total simulations which include
all components from observation target to satellite system are also
very important. We find that new software technologies, such as Object
Oriented(OO) methodologies are ideal tools for the simulation system of
JASMINE(the JASMINE simulator). The simulation system should include all
objects in JASMINE such as observation techniques, models of instruments
and bus design, orbit, data transfer, data analysis etc. in order to
resolve all issues which can be expected beforehand and make it easy to
cope with some unexpected problems which might occur during the mission
of JASMINE. So, the JASMINE Simulator is designed as handling events
such as photons from astronomical objects, control signals for devices,
disturbances for satellite attitude, by instruments such as mirrors and
detectors, successively. The simulator is also applied to the technical
demonstration "Nano-JASMINE". The accuracy of ordinary sensor is not
enough for initial phase attitude control. Mission instruments may
be a good sensor for this purpose. The problem of attitude control in
initial phase is a good example of this software because the problem is
closely related to both mission instruments and satellite bus systems.
---------------------------------------------------------
Title: Educational Pico-Satellite Project CUBESAT - University of
Tokyo's CUBESAT XI and its Operation Plan
Authors: Tsuda, Y.; Sako, N.; Eishima, T.; Ito, T.; Arikawa, Y.;
Miyamura, N.
2002iaf..confE.612T Altcode:
University of Tokyo ISSL (Intelligent Space Systems Laboratory) has
been developing a pico-satellite called "CubeSat" as an international
joint program. In CubeSat project, 10cm cubic satellites have been
developed by several universities and launched to the low-earth
orbit altogether by Russian rocket "Dnepr". ISSL has developed "XI"
series ([sai]: X-factor Investigator) satellites, and the flight
model is already fabricated and ready for delivery. The mission of XI
satellite is the on-orbit technology demonstration of the ultra-small
satellite bus system with an extensive use of commercial-off-the-shelf
components. XI transmits the Morse beacon and FM packet telemetry
which provides the health data of the satellite. Additionally, XI
has a CMOS camera which provides 15,000 pixels panchromatic images
as an advanced mission. Ground operation is one of the key issues
for CubeSats. Now we are promoting international ground station
network in which several universities' ground stations connected by
internet collaboratively operate university-built small satellites,
which enlarges the link opportunity. Collaboration with amateur HAM
engineers is also indispensable for search for the satellite or get
beacon signal to estimate the satellite orbit. We are now developing
operation concept based on these ideas. As the launch is scheduled
in this fall, the operation plan will be fixed at the time of this
conference. In this presentation the final design of ISSL's CubeSat
XI and operation plan will be presented.
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Title: Cansat suborbital launch experiment-university educational
space program using can sized pico-satellite
Authors: Sako, N.; Tsuda, Y.; Ota, S.; Eishima, T.; Yamamoto, T.;
Ikeda, I.; H,, II; Yamamoto, H.; Tanaka, H.; Tanaka, A.; Nakasuka, S.
2001AcAau..48..767S Altcode:
Our laboratory is proceeding with a project to design and fabricate a
nano satellite named "Gekkabijin" as "CanSat" project. This project was
agreed at USSS'98 as a Japan-U.S. joint venture to make satellites for
educational purpose. CanSat is, as can be imaged from the name, a Coke
can shaped and sized satellite. Our CanSat "Gekkabijin" was designed to
deploy a thin flexible membrane using centrifugal force. Before we can
launch a CanSat into space, we had a chance to put it into sub-orbit
with a support from a U.S. amateur rocket group in the name of ARLISS
Project. ARLISS Project has already taken place twice in 1999 and 2000
and we carried out 6 missions. This paper describes the objectives,
satellite design, experiment results and lessons learned of University
of Tokyo CanSat Project.
