sci fi novellas involving aliens or interplanetary travel

[Ann aka Iftcan]

Viola Grace writes short stories/novellas that are set in space. Oh, you didn't say anything about it, but Ms. Grace writes romances. She has several different series--the Sector Guard series (basically Cops in Space) then there is the Terran Times series--2000 humans are chosen to leave Earth forever and head into space. IF they can survive, prosper and have a child then more humans will be invited and eventually Earth will be allowed to join the rest of the galaxy. Then there is Terran Times 2--the next wave of humans are allowed in space--except that this time, they only have to stay for 3 years. And then finally there is the Citadel series. Basically beings with extra abilities go to (or are sent to) the Citadels to learn to handle their abilities. Some of them return home, others stay in the Citadels to teach and still others get jobs on worlds other than their home one.

Ms. Grace does a very good job with novellas and short stories. They are harder to write well since you are so constricted as to page numbers, so not all writers can do them well.

[Scott]

Great Stories of Space Travel

[Kaion]

Lots of classic sci-fi probably fits your prompt, including titles by Ursula LeGuin (The Left Hand of Darkness), Samuel Delaney (Babel-17), and Octavia Butler (Dawn.

Longer than a novella, but I read this last year, highly recommend it: Dark Orbit

[Melanti]

A recent series you might like is Binti. It involves both aliens AND space travel.

Several of the bigger sci-fi awards have categories for "Novellas". You might peruse the past nominees/winners. Aliens and space travel are sci-fi staples so you should find plenty you'd like.

https://en.wikipedia.org/wiki/Hugo_Aw...
https://en.wikipedia.org/wiki/Nebula_...

[Keith]

The State of the Art - Humanoid aliens covertly observe Earth.
Palimpsest - Focuses mainly on time travel, but also features space travel.
Story of Your Life - I haven't read this story about communication with aliens, but it was the basis for the recent film Arrival.