The failure of Japan's Akatsuki spacecraft was a last-minute affair--one of the most devastating sorts. It had completed its slow, precisely calculated journey to meet Venus at its point of Solar orbit on December 6th. The planet would have loomed large to the probe. To the JAXA crew back in Japan, the end of the probe's trip, and the beginning of its two-year observation mission, was within grasp.
Then, something happened. Or rather, not enough happened. During a maneuver intended to bring the Akatsuki into Venusian orbit, communication with the probe was lost. Once it was recovered, it became clear that the rockets that were propelling the probe into orbit didn't fire as they were supposed to. The Akatsuki had missed its chance, and won't encounter Venus again for another six years--well past the craft's intended lifespan. Until then, the Akatsuki will lazily float an in orbit around the Sun, awaiting further instructions.
It's an apt metaphor for the JAXA, the Japanese space agency that merged Japan's distinct space programs into one just seven years ago. JAXA has consistently launched and operated small satellites and completed a handful of missions near Earth, but the Akatsuki, which was only the agency's second attempt at a planetary mission, was also its second failure. (The Nozomi probe was lost in a similar attempt to enter Martian orbit in 2003.) Assessing JAXA's 0% planetary mission success rate, agency official Takehiko Satoh told Space.com, "Our score is zero wins, two losses. We have to be more conservative to plan our next planetary mission, so it will never fail in any aspect."
As far as entry barriers go, the spaceflight industry is about as unforgiving as it gets. Planetary missions can cost hundreds of millions of dollars, and in cases where they're essentially retreading previous missions, the cost can be hard to justify. Venus in particular has been extensively studied and observed, and was even the target of the first successful interplanetary mission, the Mariner 2, which arrived in orbit of the planet 48 years before the Akatsuki was due to enter orbit, almost to the day. JAXA is known as a frugal organization, but costs for a mission like Akatsuki's are still extremely high, especially when measured against the agency's modest $4bn budget.
It goes without saying that NASA's interplanetary mission success rate is higher than 0%, but failures are far from rare. Missions to Mars in particular have proven fraught, with over half of probes sent to the Red Planet experiencing some degree of technical failure. The difference is that a failed unmanned mission to Mars doesn't spark an existential crisis for NASA. An inquest, sure, and a bit of pushback from the press or Congress during budget negotiations, maybe. But it's not a crisis.
But for a smaller agency, a single failure represents the loss of a comparatively larger investment, and two failures could be enough to threaten an entire program.
This may seem like an obvious observation, but the problems of scale and entry barriers have had a huge effect of the execution of space travel in general, and cut to the heart of the biggest issues facing private space flight. Even if the barriers have fallen in the last 50 years, the expensive and failure-prone early period of a modern space program is still prohibitively expensive for many would-be comers. If JAXA's interplanetary efforts are threatened by two failures, just imagine the strain a series of mishaps could put on an even leaner, newer private entity like Virgin Galactic or SpaceX.