In [#167 Friendship One], the Delta Flyer conveys an away team to a planet suffering a nuclear winter in search of the old Earth probe called Friendship One.

Voyager is ordered by Starfleet to locate and retrieve Friendship One, an old probe launched towards that sector of space from Earth in 2067 and designed to carry a message of peace and friendship to other worlds. Contact with the probe was lost 130 years ago but its known trajectory would place it in the Delta Quadrant near to Voyager's current position. After five days Voyager locates the probe on a planet suffering a nuclear winter caused by the probe's antimatter radiation. The radiation scatters the probe's signature, making it hard to pinpoint. An away team consisting of Tom Paris, Harry Kim, Chakotay, Neelix and Lt. Joe Carey take the Delta Flyer to the planet.

the Delta Flyer about to land on the planet surface

Wearing environmental suits, Paris, Neelix and Carey follow their tricorder readings into a cavern, while Chakotay and Kim are surprised to find a field of missile silos containing active warheads. Paris, Neelix and Carey see evidence that the cavern is inhabited, but sensors have detected no lifesigns. They find a piece of debris labelled Friendship One and prepare to transport it to the Delta Flyer, but are suddenly captured by armed aliens. Meanwhile Chakotay and Kim discover the Delta Flyer has been invaded by one of the planet's inhabitants, who attacks them but is stunned by Chakotay's phaser blast. Antimatter weapons start rocking the Delta Flyer and Chakotay is forced to fly it back to Voyager, with the unconscious alien, leaving the rest of the away team behind.

Kim in the aft compartment of the Delta Flyer, about to take off and
stow the environmental suit he is wearing, unaware that he is about to be attacked

In the cavern, the natives use their hostages for blackmail, demanding that Voyager relocate the 5,500 inhabitants to the nearest class-M planet, a demand Janeway rejects as it would take 2 months at maximum warp. However, the unconscious alien Chakotay brought back in the Delta Flyer, a man called Otrin, works with the Voyager crew to devise a means of eliminating the radiation that has deformed his people. Otrin proposes an isolitic chain reaction to recombine the nucleonic particles in the atmosphere. The crew encases the catalytic agent in photon torpedoes and uses the concussive force of the explosion to start the reaction. To do this requires multiple detonations at low altitude. The agent is released and sunlight beams through the clouds onto the planet for the first time in memory. Voyager retrieves Friendship One and leaves.