Positron Generator

The Positron Generator is a ship part in Pikmin, found at The Impact Site. It is a green, rounded object with two golden antennas on the top. Olimar mentions he uses this to heat up his "Instant Space Noodles". When collected, it does not change the ship's appearance.

Collecting the part
Taking three Yellow Pikmin, go to the cardboard box that was pushed out of the way on day 1. Throw or swarm the Pikmin inside the box to pick up at least three bomb-rocks; use these to destroy the stone wall found up the ramp on the tree-stump. If the day is day 8 or over, a Mamuta (even-numbered day) or Goolix (odd-numbered day) will be in the center of the massive tree stump, so be sure to defeat them before progressing further. To create a faster route back to the S.S. Dolphin, knock down the white gate to the left of the shore now, then withdraw at least 20 Blue Pikmin and attack the Pearly Clamclamp in the water, to the left. Have your 20 Blue Pikmin take the part back to the Dolphin once it is free.

Using Red Pikmin only
Through a series of glitches, the player can obtain the Positron Generator with only Red Pikmin. It is a 2-day process that requires ending a day from the pause menu, as well as major use of the object nudging glitch, so it can be started only on day 2 or later.

Upon landing in The Impact Site, the pellet at the top of one of the ramps near the ship must not be collected. The player should first throw some Pikmin into the area outside the large stump that requires activating a geyser to reach. Then, head to the pellet at the top of the ramp and stand between it and the small lip that keeps Olimar from falling off. By lying down here, Olimar should fall past the lip and into the out-of-bounds area around the ramp. Once he gets back up (which may require moving him slightly toward the lip), the player can carefully control Olimar to lead him over to where the Pikmin were thrown. The land in these out-of-bounds parts is very slippery. After calling the Pikmin, the player can lead them over to where the white bramble gate is, being careful of the slipperiness, and throw them toward the watery area with the Pearly Clamclamps.

At the watery area, one or two Pikmin can be used to fight the Pearly Clamclamp while the rest knock down the bramble gate. The Pikmin can be thrown at the Pearly Clamclamp from a small piece of land sticking out of the water and called back when necessary, using the swimming glitch to ensure safety. Once the part is freed, the object nudging glitch can be used several times to push it towards the shore. There's no way to get it all the way up onto the shore, but by ending the day, the part will have moved up onto the shore, the next day. From there, collecting it is simple.

Trivia

 * In real life, s are, the counterparts of s.
 * When Olimar retrieves the Positron Generator, he says in his notes that if one approaches it they can receive an electric shock. However, neither him nor the Pikmin can be damaged by it in-game.
 * The Positron Generator can be seen in the enemy reel in The Distant Spring, when showing the Wogpoles.
 * There is a rare glitch that is known to happen involving this part. If collecting this part grants the player access to The Distant Spring, sometimes the propeller-like fan that comes out of the S.S. Dolphin when The Distant Spring is unlocked will appear in the cutscene, but will not be visible on the S.S. Dolphin itself for the rest of the day.
 * Oddly, this part is said to generate enormous amounts of electricity, yet the Eternal Fuel Dynamo can generate unlimited electricity.
 * When in the maw of the Pearly Clamclamp, it is technically an enemy according to game data. It is defeated once knocked loose and the real Positron Generator appears. This is the only ship part held by an enemy to be like this, likely because it is visible before obtained.
 * If the Positron Generator were somehow collected during day 1, the day would automatically end as if the player had collected the Main Engine, meaning it's not possible to collect both ship parts on the same day.