Satellite news: METEOR_M2-2 & AO-7

Bad news first:

Meteor M2-2 no longer transmits Earth images on 137 MHz.
Meteor M N2-2 is a Russian weather satellite that was successfully launched into orbit on July-5-2019 and was designed for a five-year mission.  Like with the NOAA, it is possible to receive Earth weather images from this satellite with an RTL-SDR (when it was operational).
NORAD ID: 44387
Orbit: 821 km / Sunsynchronous orbit
Mass: 2700 kg
Inclination: 98.6 °
Period: 101.1 minutes

On December-18-2019 (after only 5 months in operation), Meteor-M2-2 suffered a failure that appears to have changed its orbit. Roscosmos was quiet on the issue, however, Happysat who appears to be in contact with Roscosmos insiders has noted that on December 20 the orbit has been stabilized, and that they are working on recovering the operation of the satellite.

It has later been confirmed by Roscosmos that the satellite was struck by what is presumed to be a micrometeorite which caused a leak of thermal transfer gas, and hence a sudden orbit change. It seems unlikely that the satellite will begin operations again as the satellite cannot operate it’s camera sensors without thermal cooling. Data is being transmit currently on the X-Band, however, it appears to be a stored image only, rather than live images.
Roscosmos declared lately that on December-18-2019, an abnormal situation was recorded on the Meteor-M spacecraft No. 2-2 associated with an external impact (presumably a micrometeorite) on its structure. As a result, he changed the parameters of the orbit and switched to a non-oriented flight mode with high angular velocities (aka TUMBLE 😀 ).
In accordance with the inherent logic of operation, the device stopped fulfilling the target task and automatically switched to energy-saving mode when the on-board systems that were not involved in ensuring its functioning (including all on-board target equipment) are turned off.
After entering into the zone of Russian ground-based controls, communication was established with Meteor-M2-2, and work began to restore its operability: damping angular velocities, transferring to the standard orientation (stop tumbling 🙂 ), receiving telemetry and target information.
Currently, work is underway with the satellite under the program of the chief designer. Meteor-M2-2 is in an oriented flight; regular control sessions are conducted with it to receive telemetry information and information from target equipment.

Happysat’s Notes:
-Depressurization caused gas that was inside and used for heat transfer to leak out.
-Resulting in some devices on-board overheating, while others did stop working.
-Batteries are working under harsh thermal conditions.
-Experts analyzing MSU-MR images during the incident to confirm collision.

However, the L and X-bands are transmitting while the satellite is in daylight. There will be only short-term power-ups in the radio visibility zone, and the battery life will be reduced tenfold.
Of particular concern are the batteries. They are very quickly overheated and switching from regular to backup. Unfortunately the power supply features do not allow the 137 MHz transmitter to be used in abnormal power mode (from solar panels) which is used now, although technically it is working fine.

Meteor-M2-2 has been partially recovered, but due to low power it can no longer transmit a 137 MHz LRPT signal ever again.
The older but still operational Meteor M2 satellite has failed several times in its history too, each time with the satellite entering an unstable tumble. However, each time the satellite was recovered back into full operation after a few days. Meteor M2 remains operational transmitting on 137.100 MHz.

My last image from Meteor M2-2, December-9-2019.

The good (old) news:

AMSAT-OSCAR 7, or AO-7, is the second Phase 2 amateur radio satellite constructed by the Radio Amateur Satellite Corporation or AMSAT. OSCAR is an acronym for “Orbiting Satellite Carrying Amateur Radio”. It was launched into Low Earth Orbit on November-15-1974 and remained operational until a battery failure in 1981. Then, after 21 years of silence, the satellite was heard again on June-21-2002 – 27 years after launch.
AO-7 is the oldest amateur satellite still in use, and is one of the oldest operational communications satellites. It carries two amateur radio transponders. Its “Mode A” transponder has an uplink on the 2-meter band and a downlink on the 10-meter band. The “Mode B” transponder has an uplink on the 70-centimeter band and a downlink on the 2-meter band. The satellite also carries four beacons which are designed to operate on the 10-meter, 2-meter, 70-centimeter and 13-centimeter bands. The 13-cm beacon was never activated due to a change in international treaties.

The spacecraft is solar powered and had a three-year anticipated lifetime at the time it was launched, but it has far outlived this expectation.
AO-7 became non-operational in mid 1981 (7 years in operation) due to battery failure. In late July 2002, an amateur radio enthusiast in the United Kingdom (callsign: G4CUO) heard familiar signals from what he believed to be the “silent” Oscar-7 satellite. A quick check confirmed that Oscar-7 had indeed been somehow revived from the dead and was transmitting once again. One of the shorted batteries became an open circuit and now the spacecraft is able to run off solar panels. Since the satellite’s batteries are long dead, it can’t be used when being eclipsed by the Earth. However, when its solar panels are in the Sun, there is still sufficient power, despite four decades of constant solar panel degradation, to operate the satellite’s two repeaters. The satellite still automatically switches between the Mode-A and Mode-B repeaters, albeit more sporadically than it once did. When continuously illuminated, the mode will alternate between A and B every 24 hours.
AMSAT reported AO-7 still operational on June-25-2015, with reliable power only from its solar panels; the report stated the cause of the 21-year outage was a short circuit in the battery and the restoration of service was due to it becoming an open circuit. The satellite eclipses on every orbit during the northern summer and autumn; the rest of the year it is in continuous sunlight and alternates between transmission modes A and B. All transponders and beacons are operational.

AO-7 demonstrated several uses of new technologies and operations.
-First satellite-to-satellite relay, through AO-6.
-Early demonstrations of low-budget medical data relay and Doppler location of ground transmitters for search-and-rescue operations were carried out using this satellite.
-The Mode-B transponder was the first using “HELAPS” (High Efficient Linear Amplification by Parametric Synthesis) technology developed by Dr. Karl Meinzer as part of his Ph.D.
-First to fly a battery charge regulator.

Weight: 28.6 kg.
Shape: Octahedral 360 mm high and 424 mm in diameter.
Orbit: 1450 km.
Inclination: 101.7 degrees.

Mode (A) Linear Transponder (Non-Inverting):
Uplink: 145.8500 – 145.9500 MHz SSB/CW
Downlink 29.4000 – 29.5000 MHz SSB/CW
Approximately -100 dBm is required at the repeater input terminals for an output of 1 watt. This corresponds to an EIRP from the ground of 90 watts for a distance to the satellite of 3000 Km and a polarization mismatch of 3 dB.
Mode (A) TLM Beacon:
Downlink 29.502 MHz CW
A 200 milliwatt telemetry beacon provides telemetry data on 29.502 MHz.

Mode (B) Linear Transponder (Inverting):
Uplink: 432.1250 – 432.1750 MHz SSB/CW
Downlink 145.9750 – 145.9250 MHz SSB/CW
Approximately 50 watts EIRP is required to produce 3 watts of repeater output at a range of 3000 Km assuming a polarization mismatch of 3 db.
Mode (B) TLM Beacon:
Downlink 145.9775 MHz CW
A 200 milliwatt telemetry beacon on 145.9775 MHz provides telemetry data.

Mode U TLM Beacon:
Downlink 435.1000 MHz CW

The TLM Beacon I received on March-03-2020 on 145.9775 MHz

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