Your players need to fear androids
In Mothership(the Science Fiction Horror Role-playing Game, etc. etc.), Androids cause all nearby party members to make fear saves at disadvantage. The reasoning for this in the Player’s Survival guide is that “they tend to unnerve other crew members with their cold inhumanity.” However, much like Chewbacca and Ewocks or whatever, it makes no sense. If the characters exist in a world where androids are common, or at least as common as teamsters, marines, and scientists, they are not going to find them particularly uncanny or unusual. Common real-world simulacra of humanity like manikins and chatbots don’t cause us to freak out, so why should the average spacer get freaked out by an android?
Additionally, there is a disconnect between the supposed unease that the characters feel around the android in-game, and the players feel in real life. Unless the player really sells that their android is a total uncanny freak with their role play, interacting with their character is not going to feel different than interacting with any other class.
In Alien, characters have plenty of reasons to mistrust androids. They were synthetic people whose personalities and desires were programmed by their corporate owners. Their motives were always in question, and there was always the chance that Weyland-Yutani programmed them to kill the rest of the crew so they could take alien eggs back home. They did not cause tension because they looked like a walking manikin, they caused tension because they could flip on their crew at any time.
Players need a reason to be wary of androids, androids need secret agendas.
The secret agenda is a really good tool to connect the players to the discomfort that their characters feel around androids. If they know the android could very well be up to something that could get them killed, getting disadvantage on fear saves around them makes much more sense. Importantly, the point of giving android players secret agendas is not to add complications to the game, or necessarily cause inter-player conflict, but is instead meant to fuel paranoia and mistrust. Here are a few things that have worked for me:
Only give out hostile goals about 25% of the time. Uncertainty is the thing that fuels your player’s paranoia, not open conflict. If they know the android is certainly going to be a problem, it will not make them paranoid, it just turns them into point guards who spend the entire session prepping to body the android. But if hostility is just a possibility, the players will have to constantly second guess an android's motivations.
Simple, innocuous agendas do a disproportionate amount of work to freak out your players. Something simple as, “make sure you are always last to leave a room, and that you turn off the lights when you leave,” gives your players the space to project motivations on their android crewmember. Are they turning the lights off so something can sneak up on us? Are they always the last person to enter a room because they know something is waiting for us ahead? Strange behavior rarely goes unnoticed, and is fertile ground for players to make themselves paranoid. Importantly, this should be used sparingly, if your players are used to an android’s wacky behavior not being indicative of anything, it will not cause tension.
Agendas that put your players in danger should not always be directly hostile. For example, the goal “extract the station’s power core and bring it back” is not directed against any of the crew members, but could involve great danger to them with a radiation leak. Upper management is ambivalent to the wellbeing of their independent contractors. They want to meet expectations on their quarterly reports, not kill everyone. If android trouble is always targeted at attacking other crew members, the expectation is set that the android is an enemy. It puts players in the automatic “PVP” mindset, instead of the paranoia-fueling “what is your intention” mindset.
Agendas should be bespoke to the mission, and uniquely related to the adventure. This is quite a “no duh” thing to do, but keeping it in mind helps center the tension around what is actually going on in the narrative. It avoids the paranoia around the crew’s android ending up as a distracting B plot.
Hand out agendas publicly. If your players see you hand a note card to your android, they will know something is up and keep an eye out for it. It creates a mystery to solve, and a void for them to project their worries on to. Players will only be paranoid about the potential threat of an agenda, if they know there is an agenda they may have to worry about.
Hand out agendas in the middle of a session, especially during reveals and story beats. If the crew discover alien eggs, and the players see you hand a note card to the android, it creates a sense that things have changed, and that there are two new potential threats, and not just one. This heightens their unease, as they know something has developed that they do not have insight on. This works even if the new agenda has nothing to do with the discovery or story beat.
Lastly, android players should be the only ones that are given secret agendas. If everyone in a crew has an agenda, they are no longer special to the android, and the players do not have a reason to be worried about the android specifically. This disconnects android specific agendas, from their purpose as a tool to connect the players to their characters feelings about androids. There is a right place and time for adventures where everyone has secrets, but the goal here is to add paranoia to the “everyday” Mothership session.