Acceleration of a Rocket falling to Earth

[SophieP]

I want to drop a rocket-shaped object from a near-space balloon, with the aim of maintaining a downward acceleration that leaves it's contents in microgravity.

I think that this means:

• The (unpowered) rocket needs to maintain as close to 9.8m/s² acceleration in order to balance out the acceleration of its contents
• The terminal velocity of the rocket or it's contents will come into play - but I'm not sure if that speed is even achievable before hitting the ground

I would like to know:

1. Is it possible for an unpowered object to fall at that kind of acceleration, assuming it's aerodynamically efficient enough, and if so, how long for?
2. How can I work out it's speed for a given distance from the 'start' (i.e. point of release from the balloon?

 

[mfb]

In a perfect vacuum, you would get microgravity. Air drag will always slow you down. There is no way to achieve microgravity for more than a few seconds if you do not power your rocket to actively cancel air drag.