Somebody from the Company knew about the warning signal of alien origins, and that's all they knew according to Scott himself. They sent Nostromo first to check it out since they were going to be first on the route there before committing to sending an expensive, specialized team (as they did in Alien 3). As far as Ash, putting him there was a coincidence according to Scott, he was just there to protect the company's business.
Ridley has repeatedly shot down the suggestion that the Company was aware of the Alien payload: “I think any corporation that sends probes into unknown territory is going to think of the possibility of finding something new,” he said. “I’m sure that the crew members on all its ships would have been briefed to bring back anything of interest. It would be part of one’s job to bring it back. An alien, of course, would be of top priority. This particular corporation didn’t have a preconceived notion that an alien would be found on this mission, much less the particular Alien that is brought onto the ship. The idea of bringing it back alive would not have been on the minds of the corporate executives when they first received the alien transmission. They just had high expectations when they ordered the Nostromo to investigate – it was purely out of curiosity.”
The following passage is from the article from Strange Shapes/Alien Series blog, an exceptional writer and researcher, and a good online colleague of mine for well over a decade, with whom I collaborated a bit on JamesCameronOnline.com.
This of course also explains Weyland-Yutani’s lack of action regarding the derelict and the eggs following the events of Alien. Ridley added: “I would have thought that Earth would have previously received messages [from space], realized they were coming from an intelligent source but, for economy reasons, perhaps have postponed the preparation of an investigatory spacecraft. Then, one day, Nostromo is in the vicinity and the order is given for the crew to bring back the Alien, good or evil, without any real thought being given to the consequences."
Full Article HERE
But why would the Company place an android on their ships and keep its identity a secret? According to Ridley, they are insistent “on placing a company man on each vehicle. In this vehicle, he takes the form of a robot, Ash. This would seem to be the normal development of a huge corporation trying to protect its interests. In this particular future, it would be very easy for “pirating” to exist. Corporations will have to find ways to assure that vehicles carrying minerals or vital information will not be hijacked.”
And by all means it looks like it was a quiet inside job, like with Burke. Whoever rerouted Nostromo Burke-like got their feet wet and kept shut, then died in the meantime. And the derelict without the beacon could not be found for many reasons (the beacon was turned off/or damaged depending on continuity) until Jorden family did it decades later
