A downhole sensing device deployment control apparatus (10) includes means to control speed of the sensing device progressing within a borehole associated with a drilling operation. A mechanical, electrically powered and/or hydro-dynamic drag/damping means/device (12) can be provided as part of the control apparatus to control speed of deployment down the borehole. The drag device (12) can have a plurality of wheels or rollers to contact an internal bore of an inner pipe of a drill string. Rotation control means (24), (26) can be provided to control an amount of rotation and/or direction of rotation of the wheels or rollers relative to travel of the sensing device within the borehole. Valving (60) can be provided. A two stage (dual) flow/pressure control valve (100) can be provided. A sensing device (release 216) and downhole position latch (202) can be provided. The sensing device can be pumped into the borehole, such as by compressed air.