A fable as old as space travel itself. Popular opiniong has it tagged as a planet, but no one has ever seen it or been to it. Infact, it's very existence is disputable, spread by rumour through bars on the edge of space during the height of the Thargoid Wars.
There are many myths surrounding Raxxla. Some of them include:
That it is a planet, older than the Galaxy itself.
It is a gateway to different dimensions and time.
INRA has a base established on the planet, thus allowing them access to the gateways above.
When such legendary myths are interwined with talk of INRA, there is only one thing you can believe: Don't believe everything you hear. The sad fact is that you will only ever find out the truth if you are a member of INRA and then you wont be able to tell anyone.