From the free rules available from
GW here:
http://www.warhammerdigital.com/Downloads/Product/PDF/rules/Warhammer-40k-Battle-Primer-English.pdf
2. Make Psychic Test
A psyker can attempt to manifest a
psychic power they know by taking a
Psychic test. To do so, roll 2D6. If the
total is equal to or greater than that
power’s warp charge value, the power is
successfully manifested. A psyker cannot
attempt to manifest the same psychic
power more than once in a turn.
(underlined emphasis mine)
So, no, you can only manifest Smite once per turn.