  We have observed the cluster RX J0152.7-1357 (z$\sim$0.83) at 24$\mu$m with
the Multiband Imaging Photometer for Spitzer (MIPS). We detected twenty-two
sources associated with spectroscopically confirmed cluster members, while ten
more have photometric redshifts compatible with membership. Two of the 32
likely cluster members contain obvious active nuclei while the others are
associated with dusty star formation. The median IR-determined star formation
rate among the remaining galaxies is estimated at 22 M$_\odot$$ $yr$^{-1}$,
significantly higher than in previous estimates from optical data. Most of the
MIR-emitting galaxies also have optical emission lines, but a few do not and
hence have completely hidden bursts of star formation or AGN activity.
  An excess of MIR-emitting galaxies is seen in the cluster in comparison to
the field at the same redshift. The MIR cluster members are more associated
with previously detected infalling late type galaxies rather than triggered by
the ongoing merging of bigger X-ray clumps. Rough estimates also show that ram
pressure may not be capable of stripping the gas away from cluster outskirt
galaxies but it may disturb the gas enough to trigger the star formation
activity. Harassment can also play a role if for example these galaxies belong
to poor galaxy groups. Thus, bursts of star formation occur in the cluster
environment and could also help consume the galaxy gas content in addition to
ram pressure, harassment or galaxy-galaxy strong interactions.
