Lockheed Martin
Lockheed Martin is an undisputed big dog of the space stocks, they have a massive aerospace business and a space technology division.
Terran Orbital
Terran Orbital develops space tech from CubeSats, to small satellites, and is a developer and operator of ground stations.
RocketLab
Rocket Lab Inc. as a space investment has many large backers; space funds and tech investors large and small.