WMG: Quantum Vibe

The manned starships were sabotaged
Officially they were thrown off course by gas giant-sized clumps of dark matter. Randomly colliding with something even the size of a star in the vast gulf of interstellar space would be orders of magnitude more improbable than an in-system probe hitting an asteroid as it passed through the Belt (see Asteroid Thicket). Now think about it, an exosolar colony without FTL travel would be outside the reach of any polity or mercorp in the solar system.

Even if Quantum Vibremonics doesn't work Dr. O'murchadha has provided an outlet
His grav-sensor would be able to detect the "dark matter clumps" in interstellar space, starships equipped with them would be capable of navigating around them (or confirming they don't exist).

The events of the plot took place shortly after some several-century-spanning Dark Age
Nearly all of the popular culture references involve modern trivia, despite the story taking place five hundred years in the future (how often do you reference the 1600s?). Everyone seems to be constantly surprised by new, in retrospect glaringly obvious new uses for technology (Seamus is surprised by Nicole's new invisible belt, despite holographic clothing being ubiquitous). The existence of an era of intense warfare a few hundred years previously is heavily implied: -Mars is heavily Chinese, yet Earth is seemingly entirely European or Indian without a trace of Chinese -Lunans are shown to have once lived in caverns under the surface to protect against bombings, and have a implicitly bloody revolutionary past (Hari knows for certain his domes over the lunar cities protect against bombings, the Lunans screen visitors for weapons, and don't seem to like non-Lunans much) -Many people speak local dialects of English, with a formalized English the main language, much like Latin after the fall of the Roman Empire. Seamus claims that humanity needs to constantly be tested or its culture will start to rot and decay. Having lived from approximately our time period to 2523 AD, he has personally seen what humanity does under pressure.
  • Confirmed, to an extent. A Mad Scientist named Theophilus Farnsworth nuked the Middle East, which set off dirty bombs planted in most of the Western major cities. And then in a completely unrelated incident Yellowstone erupted and most of the Northern Hemisphere was devastated. Gensaxwal appears to be mostly Latin American (the stated leader of the reconstruction) and European, while Dokka-wing-hoy sounds Chinese.

Dr. O'murchadha is an Expy of a modern libertarian fringe scientist
There is evidence that Seamus is over 500 years old, which drops his birth quite neatly in modern times.