Defeat Libra to reach Lumos is a mission in A Crack in Time, taking place in the Korthos Sector. Upon entering the sector, Ratchet encountered three valkyrie war ships. Two of them departed to chase Alister Azimuth, leaving the third to block his path to Lumos.
Walkthrough[]
The valkyries set up a zone around the area, preventing you from leaving. Libra's warship flies in circles, repeatedly shooting at you and periodically leaving behind shockwave emitters. Her ship is slower and bigger, so focus on flanking it and using barrel rolls to avoid attacks while returning fire. Your bullets can destroy hers, but it's more efficient to evade them and hit her directly to maximize your damage per second.
Upon taking 33% damage, Libra's warship will become shielded and call in valkyrie fighters. These fighters are stronger than the usual green saucers but function similarly. Destroying ten fighters will cause Libra to drop her shields and re-engage in the fight.
Repeat this process until she shields herself again, requiring you to destroy 15 fighters. Libra will now leave behind waves of shockwave emitters but will not gain new tricks. If you need health, destroy fighters as they drop nanotech and occasionally other power-ups.
Completion of the mission allows you free reign to explore the Korthos Sector. After a minute or so, you will receive a transmission from Captain Qwark, unlocking the mission "Save Qwark from the Agorians" at the Agorian Battleplex, an arena. This can be attempted now, but it is usually better to complete missions on Lumos first for bolts and experience. Before this, it is recommended to at least complete several space missions (provided you have the Ship Tether) and acquire the Shockwave Payload mod on Korthos Sigma before attempting the next main mission "Travel to Krell Canyon, Planet Lumos".