- "A show of force is required. If they know we're here, they'll be less likely to start something."
- – Captain Pierce
Captain Pierce was an Earthforce officer and captain of the EAS Hyperion. In 2258, while en route to the Vega Colony, he received orders via the Office of Planetary Security to take his ship directly to Babylon 5 and assume control. The station commander, Jeffrey Sinclair, had just discovered the Great Machine on Epsilon III. Faced with overwhelming potential for technological discoveries, Earthforce wanted the Hyperion at the station to stake a claim for the Earth Alliance.
Upon his arrival, Pierce met with Sinclair and explained the situation. Sinclair rebuked Pierce, telling him that the station was no place for Earthforce "saber rattling." Angered over Sinclair's reaction, Pierce decides to send a team to Epsilon 3 on his own. When his ships are unable to get past the planet's defense systems, he is told by Sinclair that they need a jamming device on the station.
When Pierce realizes Sinclair was lying about such a device, he decides to send another team, despite the warnings of Varn, an alien brought back from the planet. Varn had told Sinclair that if anyone goes to the surface, the Great Machine will self-destruct, blowing up the entire planet. Sinclair activates Babylon 5's defense grid, promising to open fire on Pierce's ships if they try to land. Pierce recalls his ships. Just as he does so, a strange alien vessel jumps into local space and lays a claim to the Great Machine. Pierce flatly denies the claim and orders the aliens to withdraw.
Not long after, the alien ship attacks. Babylon 5 and the Hyperion coordinate a counterattack, but are nearly overwhelmed by the ship. Fortunately, a Minbari named Draal takes over at the heart of the Great Machine. He issues an edict forbidding anyone to approach the planet, and when the alien ship defies him, he destroys it.
Afterwards, Pierce and the Hyperion depart Babylon 5, heading back to Vega.