At the beginning of TNG: Starship Mine, Captain Picard tells Dr. Beverly Crusher to arrange with Geordi La Forge to beam a stasis unit from the ship's astrophysics lab.
Why would an astrophysics lab have a stasis unit? Is there any other time in Star Trek where a stasis unit is mentioned in relation to astrophysics that would shed light on the applications of such a device in that field of research?
The script makes it clear that the stasis unit Picard has requested isn't normally intended for medical use but is in fact some manner of scientific study apparatus (perhaps for storing gases or samples from nebulae) and that the unit can be jerry-rigged to work as a crude medical stasis chamber, presumably because they both work on the same scientific principles;
BEVERLY : Captain... Arkaria Base does not have the medical storage units I requested. I have seven living tissue samples that won't survive the baryon sweep anymore than you or I would. I've tried to reason with them, but --
PICARD : Have Mister LaForge transport a stasis unit from the astrophysics lab. You should be able to convert it to store tissue samples.
The key word here is convert.
The excellent (and moderately canon) Star Trek TNG Technical Manual indicates that "stasis" technology works by slowing atomic motion, something which would be invaluable in the study of various forms of matter and antimatter found in astrophysical phenomena;
The technology that has given rise to the QCRD is similar to that of the transporter, SIF, IDF, and other devices that manipulate matter on the quantum level. The conversion process sees the inlet of normal matter, stretched out into thin rivulets no more than 0.000003 cm across. The rivulets are pressure-fed into the QCRD under magnetic suspension, where groups of them are chilled to within 0.001 degree of absolute zero, and exposed to a short-period stasis field to further limit molecular vibration. As the stasis field decays, focused subspace fields drive deep within the subatomic structure to flip the charges and spins of the "frozen" protons, neutrons, and electrons. The flipped matter, now antimatter, is magnetically removed for storage. The system can normally process 0.08 m3/hr.
I can't think of any other references to similar situations in the show, but it seems fairly straightforward to me. Anyone studying physics, especially physics in the wild-and-wacky world of deep space in Star Trek, would find it useful to be able to freeze a sample or an experiment for storage or detailed study.
Astrophysics specifically might be keeping a space-based life form in stasis, or (depending on the meaning of "stasis") something more like a transporter pattern of some strange object or material. Or perhaps it's for producing rare materials in a lab: in the real world, many experimental elements only exist for a fraction of a second. Maybe a stasis pod slows down the atom's decay so it can be studied. Or it could be something only tangentially related to Astrophysics, like a storage capsule for an eminent physicist who is being held in stasis for some reason.
Since it's just a passing remark in that episode I doubt there is an "official use" detailed in the canon, but the possibilities seem varied enough that we can extrapolate that they have them around just in case a need arises.
