update 2: It appears Schiaparelli has already been located by satellite. This still represents the first laser ranging retroreflector array deployed beyond the Earth-Moon system! So assuming it is now oriented such that the array can be seen from space - is anything else needed, or now that the position is know is it ready for science?
update: At the moment signal reception from Schiaparelli (ExoMars EDM) has not been re-established after the parachutes should have opened. Assuming it has landed right-side up (or at least close) can the retroreflector array still be used for science? Would imagery from orbit be able to eventually pinpoint the location so that it can be targeted by lasers from future satellites and meaningful measurements be performed?
Retroreflector arrays have many uses in space exploration and physics. See this answer, and here and here for examples.
The Schiaparelli Lander carries one that seems to be the first optical retroreflector to be deployed beyond Earth orbit.
This description lists examples of what it could be used for, but are there any specific plans to bounce beams off of it any time soon?
How can Schiaparelli's retroreflector array be used if communications is not established?
The INRRI Corner-Cube Retroreflector weighs under 25 grams, is 5.5 by 2.0 centimeters in size and is envisioned to be tracked by Mars orbiters capable of laser ranging or laser altimetry, or even laser communications. Its presence on Mars may also benefit future Martian geodesy or general relativity studies. INRRI has an aluminum body with eight fused silica Corner-Cube Reflectors within it, attached by a silicone rubber.
Installing a retroreflector on a rover or lander will enable precise georeferencing during the surface exploration activity. Having precise georeferenced data is useful in tracking sites that may be of interest for future exploration or sample return. Establishing a catalog of georeferenced sites of particular interest is a priority for NASA and ESA in the agencies’ long-term goals for Mars exploration.
The INRRI reflector is wavelength-independent, providing an initial platform to explore ranging on Mars, and prove the principles of laser communications between a surface vehicle and an orbiter.