REPORT OF ADEOS INITIAL MISSION CHECKOUT

Haruhisa Shimoda
ADEOS Program Scientist
Earth Observation Research Center, National Space Development Agency of Japan

Launch

ADEOS was successfully launched at 10:53 a.m. (JST) / 01:53 a.m. (UT) on August 17, 1996 from Tanegashima Space Center. The launch was 24 minutes behind schedule. In the critical phase of the launch, ADEOS completed the following:
  1. Deployment of the solar array paddle
  2. Tracking the Sun
  3. Deployment of the NASA Scatterometer (NSCAT) antennas
  4. Deployment of the Inter Orbital Communication Subsystem (IOCS) antenna
  5. Establishment of three-axis attitude
The critical phase of ADEOS ended after the 22nd revolution on August 19. NASDA started verifying the functions of the bus system and the mission instruments on that date. The initial mission checkout of ADEOS will continue for 90 days (until the middle of November).

Initial Orbit Control

In the test injection of the thrusters on August 20, an anomaly was found in one of the four 20-Newton thrusters which were planned to be used for the initial orbit control. NASDA performed a series of initial ADEOS orbit adjustment firings using the 1-Newton thrusters from August 24 through September 8. As a result of the initial orbit firings, ADEOS has been placed into the following orbit to perform Earth observation as planned:
Apogee804.6 km
Perigee789.0 km
Orbit Inclination98.625 degrees
Period100.8 minutes
Local Time at Descending Node10:41 a.m.
Recurrent Cycle41 days
NASDA plans to conduct orbit control firings once a month in order to correct ADEOS' fall from the present orbit due to the air drag.

Status of Bus Module

  1. The initial checkouts of the Communications and Data Handling Subsystem (C&DH) and the Direct Transmission Subsystem (DT) were performed from August 21 through September 1 and confirmed that C&DH and DT are functioning normally.

  2. The initial checkout of the Mission Data Recorders (MDRs) was performed from August 31 through September 9, and it was assumed that MDRs are functioning normally.

  3. The Attitude and Orbit Control Subsystem (AOCS), the Solar Array Paddle (PDL), the Electric Power Subsystem (EPS), and the Reaction Control Subsystem (RCS) are functioning normally except for an anomaly in one of the four 20-Newton thrusters.

  4. The initial checkout of the Direct Transmission for Local Users (DTL) was performed at the same time as the initial checkout of OCTS and confirmed that DTL is functioning normally.

Status of Mission Instruments

  1. OCTS

    2. NASDA performed the initial checkout of the visible and near-infrared bands (VNIR) of OCTS from September 3 through 9. The first image of OCTS VNIR observing Japan and its surrounding waters was acquired on September 3. This image can be seen at the EORC ADEOS Home Page.

    The initial checkout of OCTS VNIR indicates that OCTS VNIR and DTL are functioning normally. NASDA has been investigating the data quality of the acquired images and continues the checkouts of the ground and space segments.

    NASDA confirmed on September 11 that the earth shield in the radiation cooler of OCTS had deployed normally. NASDA plans to perform the initial checkout of the thermal-infrared bands (TIR) of OCTS in the beginning of October.

  2. AVNIR

    3. NASDA performed the initial checkout of AVNIR from August 31 to September 7. On September 1, ADEOS took the first image of the multispectral bands of AVNIR observing Kagoshima Prefecture, in southern Japan, using the pointing function.

    On September 5, ADEOS took the first image of the panchromatic band of AVNIR observing the city of Hiroshima, a major city in western Japan, also using the pointing function. Both images can be seen at the EORC ADEOS Home Page.

    The initial checkout of AVNIR indicated that AVNIR is functioning normally. NASDA has been investigating the data quality of the acquired images.

  3. IMG

    4. The initial checkout of IMG was planned from September 20 through 24. On September 20 an anomaly was found in the scanning mirror mechanism of IMG and IMG did not work. Both MITI and NASDA have been investigating the cause of the anomaly. MITI and NASDA turned IMG on again on the night of September 24 and resumed the checkout procedures. MITI and NASDA confirmed on the night of September 25 that IMG is functioning normally. The first result of IMG observing the Earth will be reported in the beginning of October.

  4. ILAS

    5. The initial checkout of ILAS was conducted on September 17 and 18. The ILAS Project Team of NIES succeeded in deriving ozone profiles as well as other target gases above 20 km in altitude from a couple of data sets obtained during the initial checkout.

    News from the ILAS Project Leader:
    The derived ozone profiles look quite reasonable compared with ozone data obtained from previous satellite sensors. The transmittance spectra obtained from the ILAS data coincide with those calculated from the derived gas profiles, as expected. Profiles of other gases need further confirmation because of their relatively weak absorption compared to ozone. Overall performance of the ILAS instrument and data processing software has been confirmed to be excellent though some minor changes in data processing software are required.

  5. RIS

    6. The initial checkout of RIS was scheduled to be conducted from August 28 to 31, but the checkout was not performed because of bad weather. The initial checkout of RIS will be conducted in the end of September or in the beginning of October.

  6. NSCAT

    7. The NSCAT antenna was deployed on August 17, and the initial checkout of NSCAT was performed from September 13 through 15. No bad information has been received from NSCAT, and it is assumed that NSCAT is functioning normally.

    The first result of NSCAT observing the Earth will be reported in the beginning of October.

  7. TOMS

    8. The initial checkout of TOMS was performed from September 11 through September 12. The TOMS Project Team of NASA GSFC succeeded in obtaining the first global images of total atmospheric ozone from TOMS on September 12. TOMS Project Scientist was extremely pleased with the quality of this first image. Checkout of the TOMS instrument will continue throughout September and October. Day to day operations of TOMS are scheduled to begin in November.

  8. POLDER

    9. The initial checkout of POLDER was scheduled for September 16 and 26. No bad information has been received from POLDER and it is assumed that POLDER is functioning normally. The first result of POLDER observing the Earth will be reported in the beginning of October.

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