You could become a Lounge member by simply collecting Lounge points and get Lounge passes. Each Lounge pass needs 10000 points, a Lounge pass can be used for 7 days and will expire after 7 days. Each player could have at most 2 Lounge passes at a time.
Players could also collect extra Lounge passes in other events or system features, like mission badge or power missions, the extra passes' length will add up to current Lounge passes' duration.
Here are the ways to collect points: