A space safety apparatus monitoring a volume of space encompassing a field
of view (FOV) for detecting an intrusion including a gas or vapor, and
includes a micro-electro-mechanical system (MEMS) having mirror elements
in a mirror array for reflecting infra-red (IR) energy beam collected
from the FOV and an IR energy detector for detecting the IR energy
reflected by the MEMS array and converting the IR energy to an output
signal. A processor adjusts an angle of an element of the MEMS mirror
array by varying a control signal, or by switching from one to another
focusing element. The method includes detection in a volume of space by
positioning a MEMS mirror array to reflect IR signal with respect to
active elements of an IR detector; and collecting IR energy from an
i.sup.th portion of the FOV.