[Havoc]

>The earth travels at 30 km / s (70K MPH) around the sun, so you need to decelerate about that much the other way.

Surely you’d just need enough to end up in a decaying orbit? Then it’ll eventually reach the sun

[hollerith]

Low-earth orbits decay because of friction between the spacecraft and the Earth's upper atmosphere. What do you imagine would guarantee the decay of a solar orbit before a perturbation (by, e.g., the gravity of the Earth's moon or a comet) sends the orbiting object into a collision course with Earth?

[jl2718]

All you need to do is hit the Lagrange point.