Particle System Not Visible Unless Parent Selected

I'm making a "rocket boost" game as part of a Unity course. My rocket has five particle systems as children. Two of them play once when the rocket collides with different objects. Those two work just fine. However, the other three particle systems are supposed to play on loop when the player holds down a movement key (left, right, or forward). These three are not visible in scene view or in game view while playing the game unless the rocket parent object is selected in the hierarchy. As soon as I deselect the rocket, they disappear. I'm using "particleSystem.Play()" to trigger all of them. I don't think my code is to blame since they play and stop exactly as they should when the rocket is selected.

Strangely, with the rocket deselected, the particles appear for a split second if I press the print screen key, but immediately disappear again. They are also visible if I turn on prewarming, but they don't look right since they are at full length as soon as they appear. All of the particle systems as well as the rocket itself are on the default rendering layer. I'm using the current release version of the Unity editor: 2020.3.27f1