It would not have really been necessary to use a bluescreen or footage of a parachute descending in the air. All you really needed to show was Sulu talking on his communicator in the foreground, his encampment in the background with personnel scrambling in behind him, and a parachute flapping about draped over a rock behind that with the end extending off-camera. If you think about it, TOS got away with "imagination shots" many times. (It wasn't until TOS remastered that we finally got to see the Antares in "Charlie X"). So lavish FX and expensive shots would not have been necessary to pull this off. You don't actually have to see the airdrop in progress, or the capsule on the ground. Just a parachute down nearby in the background.