Present status and future plans of the Japanese earth observation satellite program

Adv. Space Res. Vol. 9, No. 1, pp. (1)217—(1)224, 1989 Printed in Great Britain. All rights reserved.

0273—1177/89 $0.00 + .0 Copyright © 1989 COSPAR

PRESENT STATUS AND FUTURE PLANS OF THE JAPANESE EARTH OBSERVATION SATELLITE PROGRAM Kiyoshi Tsuchiya,* Kohei Arai** and Tamotsu Igarashi*** *

Remote Sensing and Image Research Center, Chiba University, 1—33,

Yayoicho, Chiba, 260, Japan * * Earth Observation Center, Nasda, Oohashi, Hatoyama, Saitama, 350—03, Japan * * * Tsukuba Space Center, Nasda, 2—1—1, Sengen, Tsukuba, Ibaraki, 305, Japan

ABSTRACT

Japan is now operating 3 earth observation satellites, i. e. MOS-i (Marine Observation Satellite-i, Momo-i in Japanese), EGS (Experimental Geodetic Satellite,

Ajissi

in Japanese)

and GMS

(Geostationary Meteorological Satel-

lite, Himawari in Japanese). MOS—l has 3 different sensors, MESSR (Multispectral Electronic Self Scanning Radiometer), VTIR (Visible and Thermal Infrared Radiometer) and MSR (Microwave Scanning Radiometer) in addition to DCS (Data Collection System). GMS has two sensors, VISSR (Visible and IR Spin Scan Radiometer) and SEM (Solar Environmental Monitor). EGS is equipped with reflecting mirrors of the sun light and laser ref lecters. For the future earth observation satellites, ERS-1 (Earth Resources Satellite-i), MOS-ib, ADEOS (Advanced Earth Observing Satellite) are under development. Two sensors, ANSR (Advanced Microwave Scanning Radiometer) and ITIR (Intermediate Thermal IR Radiometer) for NASA’S polar platform

are initial stage of development. Study and planning are made for future earth observation satellites including Japanese polor platform, TRMM, etc.). The study for the second generation GMS has been made by the Committee on the Function of Agency in FY 1987.

Future

GMS

under

the

request

of

Japan

Meteorological

INTRODUCTION Japan is now operating 3 different satellites to observe the earth, i.e. GMS (Geostationary Meteorological Satellite, Himawari in Japanese), EGS (Experimental Geodetic Satellite, Ajisai in Japanese) and MOS-l (Marine Observation Satellite-i, Momo-i in Japanese) all of them are in good condition. Although these are earth observation satellites in broad sense, here in this report an emphasis will be put on nallow sense of earth observation satellites i. e. satellites to observe earth’s environment. As to the near future satellite program, ERS-i (Earth Resource Satellite-— 1), MOS-ib and ADEOS (Advanced Earth Observing Satellite) are under development. Elaborate studies have been made on two sensors, AMSR (Advanced Microwave Scanning Radiometer) and ITIR (Intermediate IR Radiometer) which were proposed by Japan for NASA’s polar platform. As to the long future plan, Remote Sensing Council consisting of representatives of governmental research institutes, universities, foundations and experts of sensors and satellites of private companies have been making study for the past 2 years

under chairmanship of Prof. K. Tsuchiya. The preliminary report was submitted to Director General, Research and Development Bureau, Science and Technology Agency in July 1987. The details of present status and future plan of the satellites are described in the following sections.

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K. Tsuchiya et a!.

(1)218

PRESENT STATUS MOS-i (Marine Observation Satellite-i) The satellite was launched at 01:23 (World T), Feb. 19 1987 from Tanegashima Space Center, NASDA (National Space Development Agency of Japan) with the following objectives. (1) Development of observation sensors, verification of their functions and performance, and experimental observation of the earth. (2) Basic experiments on a data collection system (DCS). (3) Establishment of fundamental technologies for earth observation satellites. (4) To acquire techniques for placing satellites into a sun—sunchronous orbits, tracking and controlling a satellites in a sun—cychronous orbit, operating an earth observation satellite. Present operational status. After 3 months mission check, well qualified data of 3 sensors onboard the spacecraft, MESSR, VTIR, MSR and DCS transponder have been transmitted. Asisde from observation sensors a solar paddle generating power is in the specification while fuel still remains with sufficient margin. The battery has been operating at the DOD of 20 % with a little temperature deviation. Meanwhile MOS-1 orbit was controlled within the range of 10 kms from the nominal orbit. Approximately every one month, MOS-i orbit has been adjusted in terms of spacecraft altitude while inclination maneuvering was successfully conducted during the period from April to May 1988. Satellite attitude has been stabilized except a few cases and has been controlled within the range of the specification. MOS-i verification program is smoothly proceeding with many contributions from the investigators in the world. MOS-i verification national meeting was held on Nov. 10 and 11 1987 and MOS-i verification international meeting was held during July 12-16 1988. Major troubles on MOS-1. Major trounbles encountered so far are as follows. (1) The inversion in the memory of stored command perhaps due to high energy particles. (2) Insufficient threshold level for the earth sensors.

Roll Direction of Satellite Velocity

HSR VTIR

DCS Antenna

Solar Array

Earth Sensor

1~uver

I

~

°

7 Pitch

°

Ga. Jet Th~ster ~ S Band Antenna

X—Band Antenna

Fig. 1

Outlook of MOS-i.

The Japanese Earth Observation Satellite Program

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International cooperation. Under the memorundam of understanding among Japanese government and foreign governments or an international organization the reception of MOS-l data will be made at the following receiving stations, Kiruna (Sweden, ESA), Fuchino (Italy, ESA) Tromso (Norway, ESA), Maspalomas (Spain, ESA), Bangkok (NRCT, Thailand), Alice Spring (Australian Landsat Station, Australia) and Gatineau (CCRS, Canada). The data will be also received at Japanese antarctic Showa Base (60°S, 40°E) (See Fig.2). Spacecraft, Orbit, sensor and attitude. The outlook of the spacecraft, orbital parameters and sensor specification are shown in Fig.1, Table 1 and 2 respectively /1,2/. The size of the bus unit is 127 x 140 x 148 (cm), with solar paddle extended 528 x 200 (cm), weight is approximately 740 kg. The orbit is sun-synchronous and attitude control accuracy in 3 RMS is roll and pich within 0.45° and yaw within 1.0°, stability accuracy in 3 RMS is roll and pitch within 0.016°/sec. and yaw 0.05°/sec respectively. TABLE 1

Orbital Parameters of MOS-l.

Altitude (km) Semi-major axis (km) Inclination (deg) Eccentricity Nodal period (sec) Repeat cycle (day) Orbits per cycle (revolutions) Revolution around the earth per day (revolutions) Ground trace spacing at the equator (km) Sidelap of MESSR data at the equator (km) Descending node time (a.m.)

TABLE 2

908.7 7286.9 99.1 less than 0.004 6190.5 17 237 14-1/17 167.0 7.7 around 10:08

Specification of MOS-l Sensors.

ensors item Wavelength (mn) Frequency (GHz) Resolution IFOV at surface Radiometric resolution Swath at surface Scanning method Detector Quantum level Data rate Scan rate Integration time Antenna Receiver type Power consump Weight

MESSR

VTIR

0.51—0.59 0.61—0.69 0.72—0.80 0.80—1.10

0.5—0.7

54.7+5.0 urad 50 m S/N 15—39 dB

1 mrad

100 km (1 unit) Electrical CCD (2048) 64(6bits) 8 Mbps 7.6 msec

MSR

6.0— 7.0 10.5—11.5 11.5—12.5 3 mrad

23.8+0.2

31.4+0.25

1.99 deg

1.45 deg

0.9 km 2.7 km S/N NEaT >55 dB <0.5 K (Alb=80%) (at 300 K) 1500 km

32 km 23 km Temp. resol. <1 K (at 300 K) 317 km

Mechanical

Mechanical (Conical scan)

Si-PIN diode

HgCdPe 256(8bits)

0.8 Mbps 1/73 sec

1024(l0bits) 2 kbps 3.2 sec 10 & 47 msec 50 cm~ Offset-Cassegrain Dicke

89.8 W

46.1 W

48.6 W

70.7 kg

30.2 kg

54.0 kg

K. Tsuchiya et a!.

(1)220

0

____60E

8

____129E

—

180 ~.

~

-~-~.---~

C

__

.

~ .

____ _____

____ _____

____ _____

____ ______

____ ~

.~ .-_‘—.—--_

~

9 ~

~

~~-‘c~

~

—I-,_____

j2OW~

____

—a. ____

_____c.—

-~._~____ _____

Fig. 2 Receiving stations of MOS—l data. 1: Earth Observation Center, NASDA (Japan). 2: Tokai Univ. (Japan), 3: Showa Base (Japan), 4: Bangkok (Thailand), 5: Maspalomas (Spain), 6: Fucino (Italy), 7: Kiruna (Sweden), 8: Tromso (Norway), 9: Alicesprings (Australia), 10: Hobart (Australia), 11: Gatineau (Canada).

EGS (Experimental Geodetic Satellite) /3/ Experimental geodetic satellite was launched on Aug. 13 1986 with the first H-l rocket from Tanegashima Space Center (NASDA) into a circular orbit of 1500 km altitude with inclination 50° and the nodal period approximately 115 minutes. The weight of the spacecraft is about 685 kg with global shape of radius about 1.075 m. It is equipped with reflecting mirrors of the sun light and laser reflecters. The data are utilized by Hydrographic Department of Marine Safety Agency, Ministry of Transport and Geographical Survey Institute, Ministry of Construction for the purpose of obtaining exact locations of isolated islands and the datum point of geodetic networks. GMS (Geostationary Meteorological Satellite) Since the first launch of GMS on July 14 1977 observations with GMS has been conitnously made. The present GMS is the third of its series with weight of 303 kgs. The shape of the spacecraft (cylindrical with radius 107.5 cms), attitutde control system (spin) and major observation sensors, VISSR (Visible and Infrared Spin Scan Radiometer) and SEM (Space Environmental Monitor) are same with very minor modification in specification of SEM since 2nd GMS. The IFOV of VISSR at nadir is 1.25 and 5 kms for Visible and IR channels respectively. SEM is to observe solar proton, alpha particles and electron. GMS-3 was launched on Aug. 3 1984 with N rocket No 13 from Tanegashima Space Center. The launch of GMS-4 is scheduled in 1989. FUTURE PROGRAM MOS-ib MOS-lb is same as MOS-1 with same sensors. Now it is in the stage of Preshipment Review and the review on the subsystems has been conducted. The launch is scheduled late 1989 fiscal year.

The Japanese Earth Observation Satellite Program

ERS-1

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(Earth Resources Satellite-i) /4/

The ERS-l program is a joint program between STA (Science and Technology Agency) and MITI (Ministry of International Trade and Industry). STA and NASDA (National Space Development Agency of Japan) are responsible for development of satellite bus and launch vehicle systems while the research and development of mission equipments are implemented by RRSS (Technology

Research Association

of Resources

Remote Sensing System)

and JAROS

(Japan

Resources Observation Organization) under the jurisdiction of MITI. Now the research and development of mission equipments is in the review stage of the manufacuturing and evaluation test of engineering model (EM) and the critical design of proto—flight model (PFM). The space craft is a box type, similar to MOS-l with weight of approximately 1400 kgs and will be launched to the sun synchronous orbit of 570 kms altitude with nodal period 96 minutes, recurrent period 44 days, inclination 98° from Tanegashima Space Center, NASDA with H-i rocket. Two sensors, OPS (Optical Sensor) and SAR (Synthetic Aperture Radar) will be installed. The specifications of the sensors are shown in Tables 3 (a) and (b) respectively.

TABLE 3

Specification of ERS-i Sensors.

(a) OPS(OPtical Sensor) Items

Specification Band 1 2 3 4* 5 6 7 8

Band width (Mm)

IFOY Pixel size Swath width Quantization Data rate

.52 — .60 .63 — .69 .76—.86 .76 — .86 1.60 —1.71 2.01 —2.12 2.13 —2.25 2.288—2.418 32.2 urad 18.3 m x 24.2 m 75 km 6 bits 30 Nbps

*:

Used for Stereo

(b) SAR Items Center frequency Bandwidth Polarization (Tr—Rec) Processed resolution Swath width S/A Noise Equiv Quantization Data rate Antenna size Gain Beam width (Range) (Azimuth) Side lobe level (Range & Azimuth)

Specification 1275 MHz 15 MHz H — H 18 . x 18 m 75 km > 14 dB < —20 dB 3 bits 60 Mbps 2.2 m x 11.92 m 33.5 dB(min) 5.6 deg 1.05 deg < —11.5 dB ___________________

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ADEOS

K. Tsuchiya

et a!.

(Advanced Earth Observing Satellite)

/5/

The mission objectives. The mission objectives are, (1) development of two optical sensors and global observations with the sensors, (2) development of modular satellite to achieve a basic technology necessary for the development of future Japanese polar orbiting platform, (3) experiments of an earth observation data relay using ETS-IV (Engineering Test Satellite-IV) and EDRTS (Experimental Data Relay and Tracking Satellite to implement global observation, (4) to accept AO sensors from domestic and foreign organizations to contribute to national and international cooperative programs. It wil be launched into a sun synchronous circular orbit of approximately 800 km height with H-Il Rocket in FY 1993. The total weight will be about 2800 kgs with capability of power supply of 3.5 KW. Design life time is 3 years. In addition to Japanese sensors AO sensors will be accepted. Japanese sensors. Two sensors, OCTS (Ocean Color and Temperature Scanner) and AVNIR (Advanced Visible and Near IR Radiometer) will be installed, the specification of which is shown in Tables 4 (a) and (b) respectively.

TABLE 4

Specification of OCTS and AVNIR to be Installed in ADEOS. (a) OCTS(Ocean Color and Temperature Scanner) Items Spectral band (Mm)

______________

FOV IFOV Tilt Scan Weight Power Quantization

Specification .44 .56 .77 .88 3.70 8.50 11.0

Center , .49 • .515 .62 • .66

Band width .020 .04 .08 .30 .50 1.0

12.0

1500 km 0.85 Mrad (700 m from 800 km alt) ±20deg (5 deg step) Mechanical scan 260±30 kg 300±30 W 12 bits

(b) AVNJR(Advanced Visible and Near IR Radiometer) Items

Specification Center , .55 • .87

Band width .10

Spectral band (Mm)

.45 .67

FOV

5.7 deg (80 km from 800 km alt) 20 Mrad (16 m from 800 km alt.) ±40deg Electronic (Pushbloom) 200 kg 250 V

IFOV Pointing Scan Weight Power

In panchromatic mode,the resolution becomes 8 m

1

The Japanese Earth Observation Satellite Program

Fig.

3

Outlook of ADEOS

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/5/.

AO SENSORS FOR ADEOS

In response to the Ariouncement of Opportunity (AO) for sensors to be installed in ADEOS, liSA, France, Italy and Australia proposed the following sensors.

Due to limitation

in the capacity of the bus

proposed sensors can not be installed. be made by the end of 1988.

unit and power

The selection for

all the

AO sensors will

USA TOMS (Total Ozone Mapping Spectrometer). Same as the one onboard NIMBUS-7. Proposed by NASA GSFC. Objective: Detection of O3~ 502, etc.

ACRIM III (Active Cavity Radiometer Irradiance JPL. Objective: To monitor solar and terrestial

Monitor III. Proposed by implication of total flux

variability. NSCAT (N-ROSS Scatterometer). Proposed by JPL, This is the follow on of Seasat SCAT. Digital doppler processor is improved and number of antenna is increased to 6. Objective: To observe sea surface winds and waves. MAPS (Monitoring of Air Pollution from Space). Proposed by NASA Langley Res.

Center.

Objective; To

observe total

global

distribution

of

air pollution

such as CO, etc. France

POLDER (Polarization and Bidirectionality of the Earth Surface). Proposed by CNES. Objective: To observe the bidirectionality & polarization of solar radiation effect on the ground. Italy AMIR (Advanced Microwave Imaging Radar). Proposed by Piano Spaziale Nazional of Italy. Objective: Earth observation with 5 frequency microwave radiometer. Australia SWIIS (Short Wave IR Imaging Spectrometer). Proposed by CISRO. Identification of variety of mineral resources and vegetation.

Objective:

APS(Atmoshpheric Pressure Sounder). Proposed by CSIRO. Objective: Measurement of atmospheric pressure.

K. Tsuchiya et a!.

(1)224

Japan In addition to the previous 8 AO sensors from foreign countries 3 AO sensors to measure atmospheric trace gases are proposed by Japanese government agencies, one by Ministry of International Trade and Industry, two by Environmental Agency. Japanese Sensors for NASA’s Polar Platform Following two sensors were proposed and accepted.

ANSR

(Advanced Microwave Scanning Radiometer).

The primary objectives

of

the sensor are to observe sea surface temperature and wind, atmospheric water content including cloud liquid, etc. AMSR has the Dicke type of receivers with standard noise sources. Calibration system consists of sky

horns, non-reflective terminators for high temperature around the maximum antenna temperature. For approximately 10 % of the scanning period, it observes deep space through skyhorns and non—reflective terminators for each channel, which make it possible to calibrate the data. The preliminary decided center frequencies are 6.6, 10.65, 18.7, 23,8 36.5 GHz for both H and

V components. Further development is made at NASDA. ITIR (Intermediate Thermal IR Radiometer). The main objective of ITIR is to observe solid earth. In Fy 1987 detailed studies have been made on the system configuration to achieve the maximum resolution both in radiometric and spatial resolutions. Further studies will continue to define the most effective wave length and band-width for the sensor with participation of experts in the field of earth science, mechanical and system engineering and space technology at JAROS under contract with MITI. GMS Program The launch of GMS-4 is scheduled in Fy 1989 from Tanegashima Space Center with H-i rocket. while GMS-5 launch is scheduled in FY 1993 with H-Il rocket /3/. Until GMS-5 similar sensors to the present sensors will be installed. New type of sensors are under consideration for the next generation GMS. REMOTE SENSING COUNCIL

Remote Sensing Council is an advisory committee to Director General, Science and Technology Agency. It consists of 24 members representing governmental institutes, foundations and private companies related with space remote sensing, sensors and satellites. The preliminary report on promotion of space remote sensing was submitted in July 1987 to the Director General. Further detailed studies will be made by working groups consisting of active

scientists and engineers in the fields of earth sciences, sensor and space technology, and data processing. REFERENCES 1. NASDA, MOS-l (panphlet), NASADA, (1986). 2. K, Tsuchiya, K. Arai and T. Igarashi, Marine Observation Satellite,

Remote

Sensing Rev.,3, Issue 2, 59-104, harwood academic publishers, (1987). 3. NASDA, NASDA, NASDA (1988). 4. S. Hashimoto, Current status of Japanese earth resources satellite-i (JERS-i), 2p, Rept. fo~ ISY, Hawaii. 5. NASDA, Proceeding of the first ADEOS: Advanced Earth Observing Satellite Symposium, (1988).