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SPOILER WARNING: Ender Quintet plot details follow.

The Molecular Disruption Device as seen in Ender in Exile (Comic Book).

The Molecular Disruption Device, also known as the Molecular Detachment Device, M.D. Device, Doctor Device, or Little Doctor as a play on the acronym, was a powerful weapon designed and built by the International Fleet.[1]

Design and Function

Concept art of the Little Doctor for Ender's Game (Film).

The Molecular Disruption Device utilized two beams, which when fired would meet together to create a field in which electrons could not be shared. The field would spread out in a sphere, but would become weaker the longer it dispersed. If the field came into contact with more molecules, it became more powerful and the dispersal process would start over. After the field died down, the only thing remaining would be a clump of iron molecules.[1]

The Molecular Disruption Device used similar technology to what was used for interstellar travel, called "Strong Force Field Dynamics" It was first discovered by the Formics to power ships, the device known as the Egg Drive.[2] The weapon also incorporated Gravitics, i.e. gravity manipulation in some way.[3]


Third Formic War

The aftermath of the use of the Little Doctor on the Formic Homeworld.

The Molecular Disruption Device was created by the International Fleet a few years after the end of the Second Formic War. After the discovery of the Egg Drive and how they powered lightspeed flight, the Fleet learned that the same technology could be used to rip apart anything into its constituent atoms, and weaponized it by creating the M.D. Device. It was sent along with other starships to the Formic solar systems in order to launch an invasion against their home planets. However, it was kept on a need-to-know basis.[2]

When the Third Formic War had begun under the command of Ender Wiggin, he used the M.D. Device first on a cluster of Formic ships to destroy them in one shot. The men who deployed and used the weapon didn't understand what they were and what they could do. The soldiers who saw it used in this battle thought of it as an incredibly big bomb. When the Fleet arrived at the Formic Homeworld, Ender decided to fire the weapon on the planet, reducing the entire planet and its inhabitants into clumps of iron and dirt. The soldiers who deployed and had seen the Little Doctor consume the planet also died, lost in the same vast chain reaction.[2]

Second Xenocide

The Molecular Disruption Device was also used during the attempted Second Xenocide when Lusitania was ordered to be annihilated by Starways Congress to rid the galaxy of the deadly Descolada virus. It was loaded aboard the Lusitania Fleet, which traveled for many decades to reach the planet.[4]

Moments before it was supposed to be activated, Starways Congress revoked the order to use it. However, the admiral of the Lusitania Fleet, Bobby Lands, went against his orders and fired the weapon. Despite this, the M.D. Device did not strike its target, as Jane moved the weapon back aboard the flagship of the Lusitania Fleet, resulting in its deactivation by one of the crew.[5]

Film and Novel Discrepancies

In Ender's Game (Film), the Molecular Disruption Device is portrayed as a machine with twin barrels that fire two separate lasers, carried by a massive starship. It is said to have cost 70 billion dollars to produce. When the lasers were fired at a fleet of Formic ships, they created a web of electricity-like strands which tore the fleet apart to its constituent molecules. When the device was used against the Formic Homeworld, it created a massive wave of destruction that quickly spread across the surface, but left the planet intact.[6]


  • When Jane moved the Little Doctor back onto the flagship of the Lusitania Fleet, it was quickly deactivated, with one of the crew members noting that "the instructions [for deactivation] are written all over this thing."[5]
  • In Ender's Game, the weapon is referred to as the Molecular Detachment Device, while in later published novels it is known as the Molecular Disruption Device.[1]
  • In Earth Unaware, a mining device known as the Glaser appeared, which had properties nearly identical to the Molecular Disruption Device. Both weapons utilize Gravitics in some manner, which may explain the similarities.[7][3]