nasa should have a satellite deployed into space with a garbage net (fine mesh) to orbit Earth's upper atomsphere to collect loose debris like a fishing net and re enter the Earth's atmosphere to incinerate back on re entry into Earth's atmosphere
if it floats in space the water stays sterile from contamination to really rule out that water is being measured when observed at a distance with spectroscopy equipment if that involves spectral analysis using a satellite in orbit of earth directed at a near by floating space probe of water maybe half the distance of the moon or less
it should be far away off of the surface of mars at a distance on a floating space probe since mars has constiutents in the carbon dioxide atomsphere which could lead to false postives with observation of spectroscopy meausrements at a distance as a control to determine if water is the distant realms further in outer space with telescopes and astronomical equipment
nothing proves this as an experimental control
since not all distant stars might not all be fueled by hydrogen or helium nuclear plasmonic reactions which would mean that not all planets or distant star systems form heavy elements in the same way in terms of core chemical elements known to earth similar to our chemical periodic table
since we haven't encountered water as h2o beyond the domain of this world nothing proves this except a proposed experiment to isolate a control
which would consist of a flat plate on mars about 20ft by 20ft viewable from earth
where the rover would be equipped with 80 gallons of water or more
to project a laser spectroscopy experiment from earth off of the platter of water 20ft by 20ft
to bounce back as a receiver for chemical spectral analysis at a distance
to isolate what h2o would verify as under observable galactic spectral analysis viewing the depths of outer space