Timeline - Early Space Travel (1967-2160)
timeship Aeon from the 29th century crashes in the High Sierra in California,
and is salvaged by Henry Starling who will exploit its technology to found the
company Chronowerx and initialize
the computer revolution (VOY: "Future's End").
This may be an alternate timeline. It is possible that, after the time loop has been broken in "Future's End", Starling's Chronowerx never existed.
Late 1960's On the search for Sisko, Bashir and Dax, Kira and O'Brien materialize in San Francisco for a brief moment (DS9: "Past Tense").
1969 The Enterprise accidentally travels back to Earth when passing by a black star, an effect that will later be known as the slingshot effect. The ship is detected by Air Force pilot John Christopher. A possible damage to the timeline is repaired, so that no records exist of the incident (TOS: "Tomorrow is Yesterday").
1969 A member of the Q Continuum takes Maury Ginsberg whose car has broken down to the Woodstock Festival just in time that Ginsberg can fix the sound system (VOY: "Death Wish").
1972 The Pioneer 10 probe is launched. It will be the first human spacecraft to leave the solar system, until it is destroyed by a Klingon Bird-of-Prey in 2287 ("Star Trek: The Final Frontier").
1974 Five women are brutally knifed to death in Kiev on Earth by an entity previously known as "Jack the Ripper" and later known as "Redjac" (TOS: "Wolf in the Fold").
Around 1975 The Varro generational ship begins its long journey (VOY: "The Disease").
1986 Kirk, Spock, McCoy, Sulu, Scott, Uhura and Chekov visit Earth with a Klingon Bird-of-Prey to take humpback whales to the future. They give Dr. Nichols of the Plexicorp company the formula for transparent aluminium ("Star Trek: The Voyage Home").
Late 20th century
The technology of genetic enhancement used for the Augments is developed (ENT:
"Borderland", "The Augments").
An exact date of the Eugenics Wars was not given in the story arc. The statement that the technology comes from the 20th century does not necessarily imply that the wars took place as soon as 1992. I suppose that the rather blurry statement was purposely inserted to allow to further pursue this interpretation (although it has been contradicted so often), while adhering to the revised Trek history in which there was no such thing as a global war going on in the 1990s.
1992 The book Chicago Mobs of the Twenties is published in New York (TOS: "A Piece of the Action").
1992 Khan Noonien Singh rises to power, assuming dictatorial control from South
Asia to the Middle East. Khan is the product of genetic engineering and eugenics
experiments (TOS: "Space Seed", "Star Trek: The Wrath of
The exact date and the era of the "late 20th century" were stated in the TOS episode and the movie, respectively. However, interestingly on both occasions the time of the Eugenics Wars was also referred to as "200 years ago". The background of this discrepancy is easy to explain, considering that originally TOS was intended to take place around 100 years earlier than the later established date of 2265 -- in which case it would be correct that 200 years have passed since the late 20th century. The way TOS is set now we may either accept the absolute dates with the difficulty of justifying the divergence between Khan's and the real timeline, or we may go with the relative dates which could be better harmonized with other Trek events of the late 20th and the 21st century.
1994 Claire Raymond dies of an embolism. Her husband, Donald Raymond, has her cryogenically frozen and sent into space for possible revival at a future date (TNG: "The Neutral Zone").
Microelectronics tycoon Henry Starling mysteriously vanishes after an explosion
in his office building. It will remain unknown until the 24th century that, in
the course of a time loop, he is trying to travel to the 29th century which is
finally broken when his timeship is destroyed by Voyager (VOY: "Future's
This may be an alternate timeline. It is possible that, after the time loop has been broken in "Future's End", Starling's Chronowerx never existed. Oh well, we still have Bill Gates instead. ;-)
Obviously neither genetic engineering nor space travel is that far advanced in our real world, and the political events haven't taken place either. There was a model of the DY-100 with booster rockets in Rain Robinson's office in VOY: "Future's End", but nothing else related to the Eugenics Wars seemed to exist in this episode which was -except for Starling's Chronowerx- exactly the same as the 1990s as we know them.
1996 On the planet Canopus, Phineas Tarbolde writes Nightingale Woman, a love sonnet considered to be among the most passionate for the next two centuries. Tarbolde has been inspired by a non-corporeal entity named Onaya (TOS: "Where No Man Has Gone Before", DS9: "The Muse").
1999 Voyager 6 is launched from Earth. The probe will eventually fall into a black hole, and emerge near a machine planet on the other side of the galaxy, from where it will return in 2271 ("Star Trek: The Motion Picture").
2000 On December 31, 11:59 p.m., Henry Janeway finally gives up his resistance against the Millennium Gate, a huge self-sustaining shopping mall to be built in his hometown in Indiana (VOY: "11:59").2002 The Nomad probe, constructed by Jackson Roykirk, is launched from Earth on a mission to seek for extraterrestrial life. After a collision with the alien probe Tan Ru Nomad will turn into a deadly weapon seeking to destroy any imperfect life (TOS: "The Changeling").
2004 Three Xindi travel back in time to Detroit, Michigan. They hire someone to abduct humans with different blood types, based on which they develop and almost release a bioweapon (ENT: "Carpenter Street").
2015 The London Kings baseball team has a good year, bolstered by the performance of rookie Buck Bokai (DS9: "Past Tense").
2018 Advances in sublight propulsion technologies make the sleeper ships
obsolete (TOS: "Space Seed").
All later episodes without exception assume only moderate advances in propulsion technology in the early 21st century, in a way that interstellar travel, no matter if with sleeper ships or with the new technology, wouldn't be feasible until the invention of warp drive.
2018 The Dax symbiont is born (DS9: "You Are Cordially Invited").
Early 21st century Captain Shaun Geoffrey Christopher commands the first successful Earth/Saturn space probe mission (TOS: "Tomorrow is Yesterday").
Early 21st century The Acts of Cumberland are passed, regulating the rights of beings with artificial intelligence (TNG: "The Measure of a Man").
2020's The American government creates special Sanctuary Districts for unemployed and homeless people in most major cities (DS9: "Past Tense").
2022 Henry Garcia, a resident of San Francisco, Earth, is laid off from his job at a brewery, and is imprisoned in the city's Sanctuary District (DS9: "Past Tense").
2024 Student unrest in Europe makes France an undesirable tourist destination for Earth's elite (DS9: "Past Tense").
2024 Sisko, Bashir and Dax materialize in San Francisco. Sisko and Bashir are taken to a Sanctuary District, where Gabriel Bell, who would save the lives of many hostages, is accidentally killed because of their presence. Sisko saves history by pretending he is Bell. Historical records now list Bell with Sisko's photo as the man who peacefully ended the riot (DS9: "Past Tense").
2025 Ireland is reunited as a result of the ongoing violence as a political instrument (TNG: "The High Ground").
2026 Buck Bokai, shortstop of the London Kings baseball team, breaks Joe DiMaggio's long standing record (TNG: "The Big Good-Bye", DS9: "The Storyteller", "If Wishes Were Horses").2030 Zefram Cochrane is born (TOS: "Metamorphosis").
Why did he look much older than 33 in "First Contact"? Radiation damage?
Bokai breaks Joe DiMaggio's long standing
record (VOY: "One Small Step").
This is obviously inconsistent with the above entry where this event takes place in 2026 - unless the transmission to Mars has taken six years.
2032 The ISA spacecraft Ares IV with Lt. John Kelly vanishes in a subspace ellipse while in orbit around the planet Mars (VOY: "One Small Step").
2033 A 52nd state is admitted to the USA (TNG: "The Royale").
2036 The New United
Nations rules from Earth that citizens may not be held responsible for crimes committed by their
ancestors (TNG: "Encounter at Farpoint").
The word "New" is strange, since there would be no reason to assume that the UN would need to be re-established that soon, after all the Third World War is supposed to take place later.
2030's Hovercars become popular (VOY: "The 37's").2037 NASA launches the spacecraft Charybdis on July 23, commanded by Colonel Steven Rickey. It is the third attempt to explore beyond Earth's solar system. The ship is declared missing after telemetry is lost (TNG: "The Royale").
Around 2040 Television loses its importance as a form of entertainment (TNG: "The Neutral Zone").
2042 The last finale of the Baseball World Series is attended by only 300 spectators (DS9: "If Wishes Were Horses").
2044 The space vehicle Charybdis, launched from Earth in 2037, arrives at the eighth planet in the Theta 116 system. An unknown alien intelligence has discovered a book called Hotel Royale in the possession of mission commander Richey and creates an environment based on the book in an effort to sustain Richey's life (TNG: "The Royale").
2048 On the search for Sisko, Bashir and Dax, Kira and O'Brien materialize in San Francisco for a brief moment (DS9: "Past Tense").
The Andorians begin to terraform a planetoid they call Weytahn near the Vulcan
system (ENT: "Cease Fire").
It is also mentioned in the episode that "the planet has been deserted for nearly 100 years". This would mean that the Vulcan High Command intervened soon after the Andorian colony (and the possible military base) was set up. Moreover, Soval confirmed that he was there as a part of the occupation force "almost 100 years ago". On the other hand, why would Vulcan wait until 2097 to claim the planet for themselves?
Around 2050 The conflict between the Andorians and the Tellarites begins at this time (ENT: "Babel One").
World War III devastates Earth. 600 million are killed and many of the major
cities destroyed, the governments and legal systems largely collapse (TNG:
"Encounter at Farpoint", "A Matter of Time", "Star
Trek: First Contact").
The death toll of 37 million mentioned in TOS: "Bread and Circuses" (without providing a date) was much lower. In DS9: "Dr. Bashir, I Presume", the date of the Eugenics Wars is given as 200 years before the episode which would be around 2173, more than a hundred years later. The simple explanation for this blatant mistake is that Ron D. Moore took the (already wrong) 200 years from "Star Trek II", disregarding that it would be still some 90 years until 2373.
Roughly around 2050
Jonathan Archer's great-grandfather is fighting in the Eugenics Wars (ENT:
Jonathan Archer was around 10 years old in 2121, his father looked like 40 at that time. Jonathan's grandfather was born around 2040, give or take 20 years. The Eugenics Wars should have been roughly during that time, most likely not 1992-1996.
Colonel Green demands a "purification" of humanity, killing victims of
World War III with radiation damage (ENT:
This was said to have been barely two years after the cease-fire.
Prior to 2052 The Vissians begin using trinesium for their starship hulls, a material capable of withstanding 18,000 degrees (ENT: "Cogenitor").
Prior to 2052 The Vulcan ship T'Plana is lost with all hands in a class-5 neutronic storm. (ENT: "The Catwalk").
2055 The Vulcans establish first contact with the Arkonians, who have just develop warp drive (ENT: "Dawn").
2058 V'Lar begins her diplomatic career (ENT: "Fallen Hero").
Something decisive happens that solves Earth's problems with limited fossil fuel (ENT: "Carpenter Street").
On T'Pol's remark that Earth's fuel resources are depleted, Archer says that humans were well aware of that, "until 2061, when they finally..." It does not become clear, but he may refer to the discovery of a new power source, possibly fusion. It can't really be antimatter, as this would have to be produced with lot of energy in the first place, although it might fit with Cochrane's warp flight two years later. In any case, the date seems questionable, as it would fall in a time of general chaos after the Third World War, if we assume the war was that destructive.
2064 In a commencement address at Princeton University, Zefram Cochrane mentions details about first contact with the Vulcans, including "a group of cybernetic creatures from the future". (ENT: "Regeneration").
2065 The S.S.
Valiant is the first Terran vessel to leave the galaxy. During the crossing of
the galactic barrier some crew members develop superior ESP powers, and the
captain finally initializes the self-destruct (TOS: "Where No Man Has Gone
It seems very unlikely that only two years after Cochrane's flight a fully-fledged starship leaves the solar system, and even less credible that it could ever reach the edge of the galaxy.
2066 The Ba'ku leave their technologically advanced homeworld to settle in the Briar Patch ("Star Trek: Insurrection").
2067 Friendship One is launched from Earth. Only four years after Cochrane's successful warp flight it is a deep space probe to contact other civilizations (VOY: "Friendship One").
2067 British astronomer John Burke of the Royal Academy maps the area of space that includes Sherman's Planet (TOS: "The Trouble with Tribbles").
2067 Levinius V is infested by the same parasite creatures that will later attack Deneva (TOS: "Operation: Annihilate").2067 The colony ship Conestoga leaves for Terra Nova (ENT: "Terra Nova").
Yet another way too early launch of a ship. The Conestoga must have been a large self-sustaining ship for at least dozens of settlers, and it is questionable how this could have been achieved only four years after Cochrane's brief flight with a primitive tiny ship built with all kinds of scarce materials. It could be that the Vulcans helped launch the Conestoga, but the episode made it clear that the humans did it on their own.
Around 2067 A sublight freighter vessel carrying large quantities of unstable nuclear waste products is launched by an unknown civilization (TNG: "The Final Mission").
Around 2067 The inhabitants of Argelius II undergo a great awakening, a significant cultural milestone in their hedonistic society devoted to love and pleasure (TOS: "Wolf in the Fold").
Around 2069 The Klingon Emperor dies. He will be the last in this position until 300 years later when Kahless returns (TNG: "The Rightful Heir").
Around 2072 One of the two extragalactic travelers who has been caring for the inhabitants of the Ocampa homeworld in the Delta Quadrant leaves the planet (VOY: "Cold Fire").
Around 2072 The member of the Q Continuum later known as Quinn is imprisoned in a comet (VOY: "Death Wish").
Around 2072 Bajoran technicians construct a traditional solar sailing lightship. This particular vessel will one day be used by Bajoran poet Akorem Laan (DS9: "Accession").
Around 2074 In a parallel timeline Molly O'Brien strands on the planet Golana three hundred years in the past where she spends ten years in the wilderness (DS9: "Time's Orphan").
2075 Vanik joins the Vulcan space program (ENT: "Breaking the Ice").
Around 2075 The nomadic Moneans discover the artificially created ocean planet that becomes their home (VOY: "Thirty Days").
Around 2076 A monument is erected on a planet in the Delta Quadrant, commemorating the victims of a massacre (VOY: "Memorial").
2076 The colony ship Conestoga arrives at Terra Nova, where it is deconstructed to form the basis of the colony. Bernadette Fuller, later known as Nadet, is born on Terra Nova (ENT: "Terra Nova").
2079 Earth continues the difficult recovery from the Third World War. In many regions of Earth the legal system is still based on the principle of "guilty until proven innocent" (TNG: "Encounter at Farpoint").
2081 Contact with Terra Nova is lost when an asteroid strikes the planet (ENT: "Terra Nova").
2082 Colonel Steven Richey dies in captivity on the eighth planet in the Theta 116 system (TNG: "The Royale").
Around 2086 The Lornak clan of Acamar III begins a bitter blood feud with their rival clan, the Tralestas (TNG: "The Vengeance Factor").2088 T'Pol is born (ENT: "Zero Hour").
2090 The mining colony Orpheus on Earth's Moon is established (ENT: "Demons").
Around 2090 The Andorians discover that the Aenar, an Andorian subspecies that was only known from myths, are still alive. Their existence is kept secret in the following (ENT: "The Aenar").
2097 The Vulcans claim the Class-D planetoid Paan Mokar. A treaty with the Andorians demands that both sides stay away from the planet, and a surveillance satellite is placed into orbit (ENT: "Cease Fire").
Around 2100 It is the last time in 50 years that Soval fires a weapon (ENT: "Cease Fire").
Around 2100 The E.C.S. Horizon enters service (ENT: "Horizon").
Around 2100 Berengaria is surveyed by the Vulcans. The planet is said to be inhabited by flying reptiles, some of them reportedly more than 200m long (ENT: "Bound").
Around 2102 The ECS Horizon, freighter of the J class, is launched (ENT: "Horizon").
colonization of Mars begins (VOY: "The 37's").
ENT: "Terra Nova" establishes that Utopia Planitia already exists in 2067 when the Conestoga leaves for Terra Nova. Whether this is a continuity error, depends on the definition of the term "colonization". Maybe the Voyager reference refers to a large-scale terraforming of the planet.
2105 Eight women are brutally killed in the Mars Colonies by an entity previously known as "Jack the Ripper" and later known as "Redjac" (TOS: "Wolf in the Fold").
Around 2110 Earth has become free of poverty, disease and war ("Star Trek: First Contact").
2112 An Andorian incursion to the Vulcan border takes place (ENT: "Cease Fire").
2114 Phlox begins his career as a doctor (ENT: "Damage").
Cochrane, now living on Alpha Centauri, leaves the planet with an unknown
destination. He is believed to be dead (TOS: "Metamorphosis").
If we don't want to completely disregard Kirk's line "Cochrane, of Alpha Centauri?", we must assume that Cochrane later moved to this planet.
2119 Zefram Cochrane officially opens the Warp 5 complex to build the fastest human starship
(ENT: "Broken Bow").
If we are generous, we may take 2117 as the year of Cochrane's disappearance from TOS as an approximate date.
2121 Jonathan Archer builds a model starship. The construction of his father's Warp 5 ship has not yet begun at this time (ENT: "Broken Bow").
Around 2122 Surgically altered Vulcan agents infiltrate a smuggler organization on behalf of the High Command (ENT: "The Seventh").
2123 The S.S. Mariposa is launched for colonization of the Ficus sector. The craft settles colonists on Bringloid V. It later crashes on the planet Mariposa while attempting to settle a second group of colonists. There are only five survivors of the crash, who attempt to keep their colony viable using cloning technology. (TNG: "Up the Long Ladder").
Prior to 2124 This is the beginning of Soval's permanent stay on Earth (ENT: "Awakening").2126 Travis Mayweather is born (ENT: "Dead Stop").
Buck Bokai dies (DS9: "If Wishes Were Horses").
This is based on "Buck Bokai's" statement that he died 220 years before Sisko's birth. Well, he would be over 130 years by now...
Around 2130 Ezral and his daughter Liana are the only survivors of a starship accident (ENT: "Oasis").
Around 2130 Arik Soong steals frozen genetically enhanced embryos from a secret research lab (ENT: "Borderland").
2132 The Paraagan mining colony is established (ENT: "Shockwave").
2133 Bajoran religious leader Kai Taluno, while traveling in the Denorios Belt, experiences a serious malfunction of his spacecraft and is stranded for several days. Taluno reports having experienced a vision in which "the heavens opened up", nearly swallowing his ship (DS9: "Emissary").
2133 A Klingon ship emerges from the Delphic Expanse, the crew's bodies anatomically inverted, but still alive (ENT: "The Expanse").
2135 T'Pol ends her training of reconnaissance retrieval (ENT: "The Seventh").
2136 Vulcan Captain Vanik assumes command of the starship Ti'Mur (ENT: "Breaking the Ice").
2137 On Vulcan, Syran finds the vessel containing Surak's katra (ENT: "The Forge").
2139 Charles Tucker joins Starfleet (ENT: "Unexpected").
2139 Emory Erickson's son Quinn disappears during an experiment with the subquantum transporter (ENT: "Daedalus").
2141 Travis Mayweather meets irresistible Deltan women on his father's freighter. He is 15 years old (ENT: "Bound").
Around 2141 Kov, a Vulcan who does not follow the traditional interpretation of Surak's teachings, has a falling out with his father (ENT: "Fusion").
Around 2142 Zobral and his followers begin their resistance against the government (ENT: "Desert Crossing").
Around 2142 Malcolm Reed takes part in his last family reunion (ENT: "Horizon").2143 NX-Alpha, the first of the NX prototypes, is piloted by A. G. Robinson. It breaks apart after Robinson has reached Warp 2.2. Briefly after that, Jonathan Archer and Robinson achieve Warp 2.5 with NX-Beta on an unauthorized flight. The NX prototypes are grounded for three months after the incident (ENT: "First Flight").
Tucker and Jonathan Archer become friends (ENT: "Unexpected").
This previously mentioned date nails down the exact date of the first NX prototype flight, which was not given in ENT: "First Flight". Still, it seems unusual how Tucker could rise to the rank of full lieutenant after only four years in Starfleet.
2143 The Vulcan ship Vahklas departs from Vulcan (ENT: "Fusion").
2143 The Suliban Cabal begins attacking Tandarian colonies (ENT: "Detained").
Around 2144 Arik Soong is captured and convicted (ENT: "Borderland").
2144 For over a year after the first successful flight of the NX prototype, the Vulcans are demanding additional simulations, until the admit that the engine would probably work. Eight months after that, Duval breaks the Warp 3 barrier in the NX-Delta (ENT: "First Flight").
2145 The Borg discover the Omega Molecule when they assimilate Species 262 (VOY: "The Omega Directive").
2147 Jonathan Archer
saves Charles Tucker's life (ENT: "Unexpected").
This could refer to the spacesuit training previously mentioned in ENT: "Strange New World" but there is no clue.
2147 Starfleet begins research on forcefields (ENT: "Vox Sola").
2148 Travis Mayweather meets his family for the last time until 2152 (ENT: "Horizon").
2148 Dr. Phlox meets his wife Feezal for the last time until 2152 (ENT: "Stigma").2149 The construction of Enterprise begins (ENT: "First Flight").
This is an extremely tight schedule, considering that the ship will be launched only two years later. But there is no room to predate the construction time, since we know that Tucker joined Starfleet as late as 2139 ("Unexpected"), and was already full lieutenant when he worked on the NX prototype ("First Flight") and first met Archer at the same time ("Unexpected"), six years before the construction of Enterprise ("First Flight").
2149 Several Suliban attempt to escape from the Tandarian Detention Complex 26 (ENT: "Detained").
2149 T'Pol arrives at the Vulcan compound in Sausalito (ENT: "Fusion").
22nd century Berlinghoff Rasmussen steals a time pod from the 26th century and travels to the 24th century (TNG: "A Matter of Time").
2149 According to his statement, Garos leads a survey mission to the planet A'kali in this year (ENT: "Civilization").
2149 While Emory Erickson is secretly attempting to retrieve his son Quinn who had vanished after a transporter accident ten years ago, his science ship is struck by an anomaly, actually Quinn's pattern (ENT: "Daedalus").
2150 By this
year, all countries on Earth have joined the United Earth Government (TNG: "Attached").
It is an old misconception that particularly Australia may have joined as the last country. This stance is based on a line by Beverly: "What if one nation, let's say Australia, had not joined...?" It should become clear that this remark was merely hypothetical.
2150 6 months before the launch the final selection for the captain of Enterprise takes place (ENT: "First Flight").
2150 On the planet A'kali, Riann begins to investigate what she thinks is a plague after her brother has died from it (ENT: "Civilization").
2150 Matthew Ryan eats his last steak for the next 18 months (ENT: "Fortunate Son").2151 ENT Season 1 (see here)
First contact between humans and Klingons takes place. The starship Enterprise NX-01 is launched under the command of Jonathan Archer. It is the first starship built by humans to achieve Warp 5. It is also the first starship equipped with a transporter for biotransport. Phase pistols are introduced in Starfleet (ENT: "Broken Bow"). First contact with the Axanar takes place (ENT: "Fight or Flight"). Charles Tucker becomes pregnant with a Xyrillian child. The Klingons acquire holotechnology (ENT: "Unexpected"). Tensions between the Vulcans and Andorians rise, and they culminate in the destruction of the monastery and listening post of P'Jem (ENT: "The Andorian Incident", "Shadows of P'Jem"). When a group of Ferengi attempts to raid Enterprise, Archer warns the Vulcan High Command and Starfleet of them (ENT: "Acquisition").
The transporter aboard the Enterprise is inconsistent with the fact that the inhabitants of the colony on Moab IV (TNG: "The Masterpiece Society") still have no knowledge of the existence of this technology in 2368, unless they left Earth long before 2151 (the colony was founded around 2168). Phase pistols are obviously an early version of phasers with essentially the same capabilities, although lasers will still be in use as of 2254. Considering that the Federation will need 200 years to develop the holodeck to the same perfection as the Xyrillians, it is inadequate that the Klingons acquire the technology so soon. The encounter with the Ferengi is the biggest continuity error so far, as it was made very clear that they were unknown until TNG.
Season 1-2 (see here
Enterprise rescues Ambassador V'Lar from the Mazarite homeworld (ENT: "Fallen Hero"). Humans first visit the planet Risa (ENT: "Two Days and Two Nights"). After the destruction of a Paraagan mining colony, the Enterprise mission is temporarily canceled. Actually, the Suliban are responsible for the disaster (ENT: "Shockwave"). Enterprise makes first contact with the Romulans when the ship runs in one of their minefields. England makes it to the finals of the Football World Cup (ENT: "Minefield"). Archer successfully mediates between the Vulcans and Andorians in the conflict over the planetoid Weytahn/Paan Mokar (ENT: "Cease Fire"). Archer is sent to Rura Penthe by the Klingons, but later rescued (ENT: "Judgment").
"Minefield" shows Romulans already with cloaking devices whose existence will be a big surprise 100 years later. Furthermore, they receive their name (which, along with Remus, is clearly taken from Earth's mythology) from the universal translator and from T'Pol, respectively.
2152 A peace treaty between the Vulcans and the Andorians is signed. (ENT: "Awakening").
2153 The Vulcan starship Seleya disappears in a spatial anomaly known as the Expanse (ENT: "Impulse").2153 ENT Season 2-3 (see here and here)
On Earth, a group of Borg from the sphere crash of 2063 is reactivated, assimilates a research team and hijacks a shuttle, but is ultimately stopped by Enterprise (ENT: "Regeneration"). A probe sent by the Xindi attacks Earth, killing 7 million. Enterprise is sent on a mission to avert a second attack with all necessary force (ENT: "The Expanse"). Inside the Expanse the crew encounters spatial anomalies that emerge from huge spheres (ENT: "Anomaly"). Enterprise cooperates with the Andorians to salvage a Xindi prototype weapon, but the alliance breaks up when the Andorians want to keep the weapon (ENT: "Proving Ground").
The already delicate issue of first contact with the Borg is further complicated, keeping in mind that plenty of evidence was created in "Regeneration" that would need to vanish until the 24th century. The pathetic trick of not mentioning "Borg" once is anything but a help.
Season 3-4 (see here
It turns out that the spheres were built by a transdimensional species who persuaded the Xindi to destroy Earth because of a war in which Earth would allegedly destroy their homeworld 400 years in the future. The war in the future will be actually fought by humans and Xindi as allies against the Sphere Builders (ENT: "Azati Prime"). A second, much more disastrous attack of the Xindi-Reptilians on Earth is averted, and the sphere network destroyed (ENT: "Zero Hour"). Enterprise manages to deal with the threat by Arik Soong and his Augments, genetically enhanced humans from the Eugenics Wars (ENT: "Borderland", "Cold Station 12", "The Augments"). The bombing of the Federation Embassy on Vulcan in which Admiral Forrest is killed leads to a crisis which is resolved by the discovery of the Kir'Shara, a vessel containing Surak's true teachings (ENT: "The Forge", "Awakening", "Kir'Shara"). Several Klingons contract a disease stemming from experiments with the genes of human Augments. The genetic treatment causes their foreheads to recess (ENT: "Affliction", "Divergence").
"Affliction" and "Divergence" are the perhaps most remarkable episodes regarding continuity. They ultimately solve the Klingon Forehead Problem.
Season 4 (see here)
The xenophobic movement Terra Prime under its leader Paxton attempts to expel all aliens from the Sol System (ENT: "Demons", "Terra Prime").
2158 Two women are killed in Heliopolis City on Alpha Eridani II by an entity previously known as "Jack the Ripper" and later known as "Redjac" (TOS: "Wolf in the Fold").
2158 Knowing that criminals are threatening his life, Shran feigns his own death (ENT: "These Are The Voyages").
2160 The Earth-Romulan War, which has been fought with atomic weapons, ends with the Battle of Cheron. A Neutral Zone is set up, separating Terran and Romulan space. At this time, humans have no knowledge about Romulan physiology and history. The treaty is negotiated via subspace radio (TOS: "Balance of Terror", TNG: "The Defector").