How to unlock: Receive an e-mail from Vetra [Tempest].
Here you can find the walkthrough for Vetra Nyx: A Moment Planetside quest. This is one of the smaller side quests in Mass Effect: Andromeda game that belongs to the category called "Allies and relationships". It is connected to Vetra and during the mission you must fulfill her request by meeting with her on Kadara.
Unlocking the quest
This quest should become available some time after completing Vetra's loyalty mission - Vetra Nyx: Means and Ends. You receive and e-mail with Vetra's request to meet with you in Sulfur Springs on Kadara and examine a curious finding.
Go with Vetra to Sulfur Springs on Kadara
Fly on planet Kadara and when you leave the Tempest remember to take Vetra Nyx with you, otherwise you won't be able to complete this quest. Sulfur Springs are in the center of the planet (there is a forward station near them, maybe you discovered it already). This place is presented in the picture 1.
During the cut-scene you must climb with Vetra on the vantage point. During it you can use the Narrative Action (picture 2) and help yourself by using the jump-jet or don't use this cheat. Regardless of your choice this is a perfect moment for flirting with Vetra.
Rewards for finishing the quest: XP.