Once you have unlocked the super valkerie battle armor, go back and
re-play a space mission being that you can only use the Super Valkerie
armor during space missions.  Once you have completed the space
mission.....select continue on the post-mission summary menu to
continue to the most recent mission you have reached.  You will
notice that you will begin every mission there on out with the Super
Valkerie armor regardless if its a space mission or not.  If you
quit out of your game, you will have to re-play the space mission once
more to continue on with the Super Valkerie armor.  I don't know
if this is a glitch only from my Xbox or game disc, but it seems to
work for me.  Give it a try!!