: John probably just wanted to conceal himself to the desert landscape without
: having to rely on active camouflage draining his suit's power. Sharp dark
: green lines don't blend well with sweeping sand dunes. A cloak also keeps
: the sand out.

: As simple as that...

1.) Where get raggedy cloak? Did he pick one up from a local cave or the UNSC caveman armory?

2.) What's the point of having standard camouflage when going up against Forerunner tech? Especially when there's so much that it looks like he could trip over it?

3.) I guess it could keep some sand out of his air tight, energy-shielded space armor. Unless he's trying to find Cortana with no weapons, shielding, or hermetic sealing...

My theory is that it's made out of hard light and it was fabricated by his suit's nano machines out of the sand as he walked through the desert. It acts as a second layer of energy shielding, and can form into a space ship whenever he needs off that planet.