After seeing their popularity decline (as reflected by lower TV ratings for shuttle launches), NASA decides to improve its public image by sending a man into space to whom the average American can relate. In this case, Joe Average is Homer Simpson.
At the Springfield Nuclear Power Plant, it's time for the "Worker of the Week" award to be given out. Everyone except Homer doesn't care, but he's confident he will win after reading the employee handbook and finding out that an employee 'must' win the award at least once, regardless of incompetency. However, Mr. Burns gives the Worker of the Week award to an Inanimate carbon rod. Homer is infuriated, and starts to feel dejected that no one likes him.
He turns to the TV for solace and ends up on a channel that is broadcasting a live space shuttle launch, which he finds dull and changes the channel. Meanwhile, NASA learns that its Nielsen ratings have declined, and decide to send an "average shmoe" into space after realizing the popularity of blue collar comedy programs. At that moment, Homer telephones NASA to complain about their "boring space launches", which makes NASA realize that they have found their man. But when they arrive at Moe's Tavern, and confront Homer, he thinks he is in trouble and blames Barney for making the prank call. The NASA employees ask Barney to be an astronaut, and when Homer realizes what the proposal entails, he steps in and takes credit for the call.
NASA takes both Homer and Barney to Cape Canaveral to train them into astronauts. They casn only take one into space, so they pit the two in competition against one another. Under NASA's alcohol ban, Barney quickly develops superior skills and is selected to fly with Buzz Aldrin and astronaut Race Banyon. However, when Barney toasts his victory with Champagne, he instantly reverts back to his normal alcoholic self and injures himself. This is a surprise to NASA, as the Champagne was non-alcoholic. Homer wins by default and is selected for space flight, but is very nervous about going. Just as they prepare to take off in the Corvair space shuttle, Homer runs away. He talks with Marge on the phone, and she says that he ought to take advantage of going into space. He agrees and the launch proceeds. To NASA's delight, it is a Nielsen ratings smash.
Homer has smuggled potato chips on board, and when he opens the bag they start to float around the cabin. The crew is initially worred they'll clog the instruments, but Homer's appetite seems to save the day as he floats after the chips in zero-G, gulping them down to the tune of the Blue Danube. All is going well until he flies into an ant farm, destroying it, and letting the ants loose in the shuttle. James Taylor comes in over the radio to sing a song, but the disaster continues on board as the ants destroy the navigation system. James Taylor suggests that they blow the bugs out the front hatch, which the astronauts do, but Homer fails to put on his "shuttle belt" and is nearly blown out of the open hatch before grabbing its handle and clinging for life. Buzz pulls him inside but due to the vacuum's sheer force, Homer breaks the hatch handle, dooming the shuttle as it is unable to land. Angered, Homer attacks Buzz with the closest weapon, and inadvertently uses a carbon rod to seal the door shut and they return to Earth.
Although Buzz Aldrin declares Homer the hero, the press see the Inanimate carbon rod as being the bigger hero. The rod is then featured on magazine covers with the headline "In Rod We Trust" and is given its own ticker-tape parade. Back at home, Homer is disappointed that he did not get as much respect as he had hoped, but the family still honors him for his achievement.
"Deep Space Homer" was written by then-executive producer David Mirkin and is his only writing credit for The Simpsons. Mirkin had worked on the idea for the episode for a long time, basing the story on a NASA scheme to send normal people into space in order to spark interest amongst the general public. There was some controversy amongst the show's writing staff when the episode was in production. Some of the writers felt that having Homer go into space was too "large" an idea.Matt Groening felt that the idea was so big that it gave the writers "nowhere to go". As a result, every aspect of the show was worked on to make the concept work. Several silly gags were toned down to make the episode feel more realistic, including an idea that everyone at NASA was as stupid as Homer. The writers focused more upon the relationship between Homer and his family and Homer's attempts to be a hero.
Buzz Aldrin, the second man to walk on the Moon, and James Taylor both guest star as themselves in this episode. Some of the writers were concerned about Aldrin's line, "second comes right after first", feeling it was insulting to Aldrin. An alternative line was written: "first to take a soil sample", but Aldrin had no problem with saying the original line. A version of James Taylor's "Fire and Rain" was recorded specifically for the episode containing some altered lyrics. Taylor's original recording session was included as an extra on the DVD.
Although the episode was directed by Carlos Baeza, the potato chip sequence was directed by David Silverman. Some computer animation created using an Amiga was used in the sequence in order to make the potato chip rotation as smooth as possible. This was the only episode of The Simpsons written by David Mirkin, who was also the executive producer at the time.
NASA loved the episode, and astronaut Edward Lu asked for a copy of it to be sent on a supply ship to the International Space Station. The DVD remains there for astronauts to view.
"Deep Space Homer" is MSNBCs fourth favorite episode, citing Homer's realization that Planet of the Apes is set on Earth as "pure genius."Empire magazine named it a "contender for greatest ever episode", and listed it as the third best movie parody in the show. In his book, Planet Simpson, Chris Turner names the episode as being one of his five favorites, saying it is "second to none," despite listing "Last Exit to Springfield" as his favorite episode. He described the long sequence that begins with Homer eating potato chips in the space shuttle and ends with Kent Brockman's dramatic speech as being "simply among the finest comedic moments in the history of television". The scene is an homage to 2001's early scene in which a space shuttle docks with a space station. The Daily Telegraph also named the episode among their ten favorites.
Both Buzz Aldrin and James Taylor received praise for their guest performances. IGN ranked James Taylor as being the twenty-first best guest appearance in the show's history. The Phoenix.com published their own list of "Top 20 guest stars" and Taylor placed eighteenth. Among The Simpsons staff, the episode is a favorite of David Silverman. On the other hand it also contains one of Matt Groening's least favorite jokes, when Homer's face changes into Popeye and Richard Nixon while exposed to G-force.
"Deep Space Homer" is the source of the "Overlord meme", which is lifted from Kent Brockman's line "And I, for one, welcome our new insect overlords" and is commonly used on internet forums when a "participant vastly overstates the degree of oppression or social control expected to arise from the topic in question" or to express mock submission, usually for the purpose of humor. The term was used by New Scientist magazine.