​NOAA-18: Thank You.

As today is the 21st anniversary launch of NOAA 18, I thought why not make a blog post for this now sadly deactivated  weather satellite.

​"Image Credit: NOAA/NASA"

Back in February 2020 I decided to try out my then new Yaesu FT818 with a bit of weather satellite imaging .

I constructed the antenna, soldered the connectors, tuned the radio, connected my laptop, plotted the path and adjusted my compass. 

The NOAA 18 Weather Sat was my goal.

The pass times were displayed  on my WXtoIMG program.

Now, all I had to do was listen to the static until that familiar "tick tock tick tock" sound tentatively pushed its way through the static of that far away horizon.

Then for the next five/ten minutes or so the "tick tock" filled my radio speaker and slowly but surely an image appeared on my screen, the NOAA-18 was passing overhead now and the signal noticeable stronger. 

As NOAA 18 raced away from me the "tick tock" lessened in intensity until finally it disappeared once again into the increasing static. 

Image: GW3MJB

NOAA 18 is no longer active, and I miss the thrill of snagging the weather images as they streamed down from above; 

a satellite fishing of sorts.

Here are some specifics of that hardy satellite. 

​NOAA-18: The Final Mission Profile

​Born: May 20, 2005 (Launched from Vandenberg AFB on a Delta II rocket)  

​Retired: June 6, 2025 (Officially decommissioned at 17:49 UTC)  

​Service Life: 20 years and 17 days (Originally planned for only 2 years)  

​Final Orbit Count: Over 103,500 orbits around the Earth.

​Total Distance Traveled: Approximately 4.7 billion kilometers (That is roughly 31 times the distance from Earth to the Sun!)

​Why it was special.

​NOAA-18 was the first of the POES (Polar Operational Environmental Satellite) series to carry the Microwave Humidity Sounder (MHS), which significantly improved our ability to "see" through clouds to measure atmospheric moisture. 

It was also a critical part of the Cospas-Sarsat search and rescue system, helping save thousands of lives by relaying distress signals from remote areas.  

​The Final Moments.

​The satellite didn't just "get old"—it fought until the very end.

​The Cause: 

On May 31, 2025, its last remaining S-band transmitter (STX-4) suffered a power drop from 7W down to 0.8W.   

​The Decision: Without a strong enough signal to reliably send commands up or get data down, NOAA made the difficult choice to "passivate" the satellite—draining its batteries and shutting down its systems to ensure it wouldn't accidentally explode or interfere with other spacecraft.

Image: GW3MJB 

It saw every single spot on Earth at least twice every day for two decades.

For years, it was famous in the hobbyist community for broadcasting on 137.9125 MHz.

For twenty years, NOAA-18 was a silent observer, watching over our storms, oceans, and our adventurers. 

While NOAA 18 may now be quiet, the decades of data it provided will continue to help us all understand our changing planet for years to come.

 Thank you for the view.