Artemis 1 Mission

Maxar’s RADARSAT-2 Loses Use of its Gyroscope and Loses WorldView-4 Satellite

RADARSAT-2 painting. Credit: MDA.

Canada’s only operational radar satellite, RADARSAT-2, has lost the use of its gyroscope and will now rely on the spacecraft’s three other types of sensors for attitude reference. And in just released news, Maxar announced today that the WorldView-4 satellite control moment gyros have failed and they don’t expect the spacecraft to recover.

RADARSAT-2 gyro malfunctions again

RADARSAT-2 was launched on December 14, 2007 and had a design life of seven years. Almost 11 years to that date, and four years beyond its design life, the satellite automatically went into safe mode on December 15.

It wasn’t the first time the satellite had an issue with its gyroscope. According to the European Space Agency Earth Observation (EO) Portal, the gyroscope malfunctioned in March of 2012.

Specifically the EO Portal stated “a transient event (SEU) caused a malfunction of one of the gyroscope in March 2012. The transient caused an attitude divergence, leading to a Processor Module (PM) restart. Payload and many bus units were switched off resulting in several hours recovery. This anomaly had been observed by the manufacturer on another spacecraft.”

The RADARSAT-2 satellite deployed configuration diagram
The RADARSAT-2 satellite deployed configuration diagram. Credit: MDA/CASI. (Click for larger version)

SpaceQ spoke with Michel Doyon, Manager, Flight Operations at the Canadian Space Agency (CSA) who said MDA worked the problem and had a solution that enabled the spacecraft to resume operations on the evening of December 20.

Doyon told SpaceQ the spacecraft is back to operating nominally and that the CSA expects the spacecraft to keep functioning for several years to come. Details of the issue and the fix would need to be addressed by MDA according to Doyon, as MDA was the prime contractor and manages satellite operations.

The fix

SpaceQ also exchanged email with a MDA representative over the holidays to answer specific questions regarding the gyro malfunction.

RADARSAT-2 uses four sensors for the spacecraft’s attitude reference. They include two Sun sensors, a magnetometer (3 axis), two star trackers and a four axis gyro. The illustrations below show the satellite’s Integrated Control Subsystem in the satellite bus and the attitude reference sensors.

RADARSAT-2 Integrated Control Subsystem (ICS) diagram
RADARSAT-2 Integrated Control Subsystem (ICS) diagram. Credit: MDA/CASI. (Click for larger version)
RADARSAT-2 Integrated control subsystem block diagram
RADARSAT-2 Integrated control subsystem block diagram. Credit: MDA/CASI. (Click for larger version)

According to MDA their “flight operations team that operates RADARSAT-2 had already been preparing to include in the next maintenance activity an upgrade to the attitude determination sensors to accommodate a gyro anomaly. The previously planned upgrade was successfully implemented and RADARSAT-2 has returned to routine imaging delivering with no impact on product quality, or imaging capacity.”

In other words, MDA thought the gyro would likely fail and was preparing for that eventuality. It just so happened that the gyro failed before the scheduled upgrade.

I asked MDA if the gyro could be fixed and be brought back online. Their response was that “the affected gyro has been tested and is not expected to produce valid data any longer. As noted above, with the upgraded attitude control system, there is no expected impact on operational capacity or long term reliability.”

So the satellite will now function using its other sensors for attitude reference. That the satellite will continue to function normally suggests that some forethought was given to this failure scenario.

MDA said “the software upgrade to the attitude control system allows the system to operate with less reliance on attitude data coming from the gyro system by prioritizing the data coming from one of the other attitude determination sensors (called Star Trackers). This is a well proven approach and is flight proven on similar satellites.”

With respect to satellites remaining life span, MDA said “the upgrade to the attitude determination system reduces the vulnerability of the gyro’s and RADARSAT-2 remains very healthy with an expected long operational life delivering reliable solutions to Government of Canada and global users.”

RADARSAT-2 importance to MDA

There’s no question that MDA has made the most of its partnership with the government with respect to maximizing revenue from RADARSAT-2. However, the spacecraft is now entering its 12th year of operations. The gyro failure wasn’t unexpected. The question is, how many years does RADARSAT-2 have left in it? That’s an important question in projecting future revenue from the satellite.

When RADARSAT-2 fails MDA and its parent company Maxar will be left with a hole in its portfolio of satellite assets. Currently the company has no other radar satellites planned.

To note though, MDA is the prime contractor for the RADARSAT Constellation Mission (RCM) which is expected to launch within a few months. The three satellite constellation, the follow-on to RADARSAT-2, is owned by the government and MDA will not have real-time access to the data to commercialize it. The government has pledged to provide RCM data to the public through their Open Government initiative. However, what data will be available, and when will it be available, has not been disclosed yet.

Losing WorldView-4

The year hasn’t started well for Maxar. Just this morning, the company announced that its DigitalGlobe business unit had lost the use of the WorldView-4 satellite.

The company said the “WorldView-4 satellite experienced a failure in its control moment gyros (“CMGs”), preventing the satellite from collecting imagery due to the loss of an axis of stability.”

Furthermore the company said “efforts are ongoing in conjunction with its suppliers in an attempt to restore satellite functionality, but thus far these efforts have been unsuccessful. At this time, Maxar believes that WorldView-4 will likely not be recoverable and will no longer produce usable imagery. Maxar operations has put the WorldView-4 satellite in a safe configuration and will continue to monitor the satellite’s location and health. The satellite was built by Lockheed Martin and the CMGs were provided by Honeywell.”

The satellite was launched in November of 2016.

Maxar said “WorldView-4 satellite is insured for $183 million, and Maxar intends to seek full recovery for the loss of WorldView-4 under its insurance policies.”

About Marc Boucher

Boucher is an entrepreneur, writer, editor & publisher. He is the founder of SpaceQ Media Inc. and CEO and co-founder of SpaceRef Interactive LLC. Boucher has 20+ years working in various roles in the space industry and a total of 30 years as a technology entrepreneur including creating Maple Square, Canada's first internet directory and search engine.

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