A pulsing and powerful orange light that emitted from an unknown object that slowed to a standstill in the sky before ascending west.

I saw something very unusual. Dare I say a UFO. What I feel is that it was not a plane. I was on my run just around Redondo Union High School in Redondo Beach, CA. What I saw was what I first mistook as a plane flying by in the lower troposphere, but what was unusual was the VERY BRIGHT ORANGE LIGHT it was emitting. Far brighter than any light a plane would be emitting. I saw it flying closer into vision only to see it decelerate in the night sky, almost to a standstill. After watching it linger and continue to emit bright orange in the sky as it seemed to approach from the eastern sky, I saw it once again accelerate… continuing to emit its bright orange luminosity. It flew away into the horizon into the Oceanside western sky. As it flew west, it seemed to ascend further into the stratosphere, and then mesosphere, until its bright orange light faded as I kept peering from my phone to the UFO . It’s all in the name, UFO, unidentified flying object. So, I can’t tell you what it was, because I honestly don’t know. I doubt it was a plane though. If this were a drone, it had a very powerful orange emitter to still be seen if it ascended towards the mesosphere.