Hemmer
Lieutenant Hemmer was a male Aenar Starfleet officer who lived during the mid-23rd century. He served as chief engineer aboard the  in the late 2250s. ()

Early life  
Before joining Starfleet, Hemmer had dreams of becoming a botanist, as he had a passion for flora. ()

He was a gifted engineer, though, and confident enough to call himself a "genius". ()

It was uncommon for the deeply pacifist Aenar to join Starfleet, although Hemmer once explained that pacifism was not the same as passivity and he would - even if he wasn't willing to fight - defend Starfleet's ideals. For him, pacifism was the active protection of all living things in the natural universe. Like all Aenar, Hemmer believed that death only came after one had fulfilled their life's meaning. He considered it his purpose in life "to fix what is broken". ()

Starfleet career 
At some point prior to 2259, Hemmer served aboard the . ()

Hemmer arrived aboard the Enterprise in 2259, succeeding Louvier as chief engineer. (; )

Shortly after arriving on the Enterprise, Hemmer formally met Cadet Nyota Uhura during a gathering in Captain Christopher Pike's cabin. He, along with Lieutenant Spock hazed Uhura by thinking she had offended Hemmer when offering to help due to Hemmer being blind. 

He later helped retrofit several photon torpedoes to help move the comet C/2260-Quentin. ()

During the Enterprises mission to Hetemit IX, He assisted Chief Kyle when Kyle was having trouble transporting the landing party from the planet. ()

When the Gorn attacked the Enterprise, he was in the main cargo bay and was injured. Due to injuries, he told Uhura how to replace reactors. ()

When an alien consciousness from the Jonisian Nebula brought the fairy tale The Kingdom of Elysian to life on the Enterprise, Hemmer was supposed to be used for the character of Caster. Because of his telepathic abilities, he was able to resist the possession and was able to contact the consciousness and helped resolve the situation. However, Hemmer didn't retain his memories of the events after the ship was returned to normal. ()

Hemmer joined the away mission to Valeo Beta V in 2259, hoping to find and recover the  and its crew. They discovered the ship had picked up three survivors from a Gorn breeding planet - two of them infected with Gorn eggs. Hemmer managed to repair the ship's generators, but was sprayed with venom by one of the newly hatched Gorn. After helping to lure another young Gorn into a trap in the Peregrine's cargo bay, Hemmer sealed off the bay and sacrificed himself to protect the rest of the away team, as he had realised the Gorn's venom had also infected him with eggs. After bidding farewell to his friend Spock and encouraging Uhura to remain in Starfleet, he was content, because he had lived a good life.

Hemmer then stepped out through the cargo bay's forcefield and fell to his death in a ravine. ()

Appendices

Appearances

Background information 
Hemmer was played by Bruce Horak. While Hemmer wears Commander stripes on his uniform, he was referred to as "Lieutenant" by Nyota Uhura in . As script/dialog is always taken over costuming, this constitutes a costuming error. It is also unlikely that a chief engineer would outrank the Executive and Second officers.

Aenar
Starfleet operations personnel
USS Enterprise (NCC-1701) personnel