o ▁Sec o ▁by ▁the ▁California ▁Institute ▁of ▁Technology . ▁During ▁the ▁ 1 9 5 0 s , ▁J PL ▁was ▁heavily ▁involved ▁in ▁ro cket ▁testing , ▁and ▁the ▁ro ar ▁of ▁ro cket ▁engines ▁could ▁be ▁heard ▁em an ating ▁from ▁the ▁Ar roy o ▁Sec o ▁area ▁for ▁miles . ▁These ▁ro cket ▁projects ▁were ▁terminated ▁at ▁the ▁facility ▁by ▁ 1 9 5 8 . ▁By ▁the ▁mid - 1 9 6 0 s , ▁J PL ▁had ▁become ▁instrument al ▁in ▁the ▁development , ▁launch ing , ▁and ▁tracking ▁of ▁a ▁number ▁of ▁un mann ed ▁near - E arth ▁and ▁deep - space ▁space ▁prob es ▁for ▁the ▁National ▁Aer onaut ics ▁and ▁Space ▁Administration . ▁One ▁notable ▁project ▁was ▁the ▁Mars ▁R over , ▁which ▁has ▁returned ▁a ▁number ▁of ▁pan or am ic ▁photos ▁of ▁the ▁Mart ian ▁surface . ▁ ▁J PL ▁has ▁been ▁critic ized ▁by ▁regional ▁environmental ists ▁and ▁the ▁community ▁for ▁its ▁water ▁poll ution ▁of ▁the ▁local ▁ground water ▁with ▁to xic ▁chemical s , ▁such ▁as ▁sol vent s ▁and ▁per ch lor ate ▁ro cket ▁fuel ▁acceler ants . ▁A ▁monument al ▁clean up ▁project ▁by ▁NASA ▁has ▁begun , ▁which ▁includes ▁a ▁mult im ill ion - d ollar ▁p ump ing ▁and ▁water ▁fil tr ation ▁system ▁to ▁treat ▁the ▁ground water , ▁removing ▁to x ins ▁until ▁the ▁aqu ifer ▁cont am ination ▁level ▁has ▁been ▁reduced ▁below ▁their ▁feder ally - spec ified