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Latest News

2000-04-19 :

German and Japanese Satellites Confirm Cosmic Plasma Process

Equator-S and Geotail find long sought plasma process.

Press Release

1999-04-27 :


In spite of its short life-time, EQUATOR-S has provided highly valuable data.
This is demonstrated by the fact that 16 papers with EQUATOR-S results have been submitted for a special issue of Annales Geophysicae, to appear in late 1999.
In addition, a special one-day session on "Equatorial ISTP Science and EQUATOR-S" has been scheduled for the June 1999 Meeting of the American Geophysical Society (AGU) in Boston.
In March 1999, a workshop on Geotail/EQUATOR-S conjunctions was held in Kyoto, Japan.

Götz Paschmann

1998-09-28 :

EQUATOR-S still not recovered

Although the hope that EQUATOR-S would heal itself is not completely gone, all signs indicate that the spacecraft did not recover from the failure which occurred on May 1st, 1998.
The available evidence indicates that the May 1 failure of the redundant processor system was caused by a latchup in one of the memory chips of the processor system, as was the failure of the prime processor system on December 17 1997. The goal of the recovery effort was to use a sequence of eclipses of the sun by the earth to drain the batteries until power to the processor-systems was lost and the latchup condition removed. The recovery effort started with the occurrence of the first eclipse day (17 August), and GSOC has been tracking Equator-S three hours every day since.
By now, after about 40 eclipses (of about 1 hour duration each), the spacecraft should have responded if the batteries had indeed been drained enough. But for this scheme to work, no re-charging of the four batteries by the solar generators in-between the eclipses was to occur. Charging of each of four batteries is controlled by a separate control bit. To prevent all batteries from being re-charged would thus have required all four bits to remain zero. But because the state of the bits is likely to be random, chances were only one in sixteen for this condition to hold. This explains why expectations for a successful revival actually were quite low.

Götz Paschmann

1998-05-05 :

EQUATOR-S stopped sending data

At the regular telemetry contact with the Weilheim ground-station on May 1, it was discovered that EQUATOR-S did not send data anymore, although the TM-signal was unchanged. We attribute this behavior to a failure of the redundant processor, similar to the failure of the first processor on 17 December 1997. All attempts to command the spacecraft failed. However, GSOC will continue this effort.
If a latch-up caused by penetrating particle radiation was the cause of the failure, there is hope that it may heal itself upon the next eclipses because of the complete temporary switch-off of the electrical system. Unfortunately, the first eclipses will only occur in the second half of August.

Until then we will enjoy working on the data received during the first five months.

May 4, 1998
Gerhard Haerendel and Herwig Höfner

1998-04-28 :

EDI results during routine operation

An example of routine operation results of the Electron Drift Instrument (EDI) on board EQUATOR-S have been made available.

1998-04-04 :

New world record set by the GPS receiver on board EQUATOR-S

The most distant GPS signal ever recieved was the one from GPS satellite PRN 30 which was received on March 31, 1998 by the GPS receiver on board EQUATOR-S from a distance of 61000 km.
(more information on the GPS receiver)

1998-03-16 :

Routine operations started

After some troublesome transition phase, EQUATOR-S now operates routinely .

1998-03-03 :

First PCD result

The first results of the Potential Control Device (PCD) routine operation on board EQUATOR-S have become available.
(Data are from January 27, 1998)

1998-02-05 :

Frequently Asked Questions (FAQs) page started.

FAQ Page

1998-01-26 :

First ICI (formerly ESIC) result

The first result of an Ion Composition Instrument (ICI) measurement on board EQUATOR-S has become available.
(Data are from January 8, 1998)

1998-01-19 :

First EPI result

The first result of an Energetic Particle Instrument (EPI) measurement on board EQUATOR-S is available.
(Data are from December 16, 1997)

1998-01-05 :

EQUATOR-S WWW site selected as "Site of the Week"

The EQUATOR-S WWW site has been placed on the "SpaceViews Space Sites of the Week" list for this week. This is a list recognizing excellence among space-related Web sites.

1997-12-23 :

First Phase of Commissioning Completed

The first phase of EQUATOR-S commissioning has been completed. So far, instrument performance is nominal. Because of occasional spurious commands from the spacecraft that can turn instruments and mass-memory on and off at random, only real-time operations are possible at present. Corrective actions are being investigated.

1997-12-15 :

First MAM Measurement

The first MAM measurement was carried out successfully on December 12th.

A plot showing the variation of the magnetic field magnitude during about 4 hours is available.

1997-12-11 :

Kick-Manoeuvre successfully executed

The kick-manoeuvre was successfully executed on Thursday, December 11 at UT 18:38:16 and could be witnessed from Canberra ground station. The final orbit is now 500 x 67300 km.

The remaining TM and GPS antennas were deployed soon after, and finally the two magnetometer booms. The spinrate after boom deployment is 40.35 rpm.

All the subsystems and scientific instruments onboard have been switched on at least once; up to now no nonconformances have been reported.

1997-12-06 :

Kick-Motor Burn scheduled for December 11th

After some minor problems have been solved, EQUATOR-S is now working as planned.
The two technological experiments GPS Receiver and Solar-Cell Diagnostics operate since the beginning of the mission. The only scientific experiments switched on so far are the Magnetic Field Instrument (MAM) and the Scintllating-Fiber Detector (SFD) .

Another 10 orbits will be needed to increase the spacecraft's spin rate to 48 rpm using the magnetorquers and to determine the exact attitude of the spacecraft. Both are neccessary before the kick-motor can be fired.

At this time, the kick-motor burn is scheduled for 18:35 UT on Thursday, December 11th.

Immediately following the injection into the final orbit, the deployment of the magnetometer-booms and the switch-on of all remaining scientific instruments is planned.

1997-12-02 :

Successful launch of Ariane 44P and Equator-S

23:52:32 UT on December 2nd, Ariane V 103 was launched and about 24 minutes later released EQUATOR-S into the transfer orbit.

Last update of this page 1999-04-27 by Helmut Steinle . Please send comments to !

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