It’s claimed by its owner, Russian President Vladimir Putin, to have unlimited range and be able to outflank all US air defenses. But this month, it proved, for a Kremlin keen to emphasize its growing military muscle, yet another high-profile hiccup.It wouldn’t be the first time that a test of the missile wasn’t entirely successful, according to US officials.But what is Skyfall? In truth, analysts don’t really know, but their guesswork leads them to believe it’s a form of cruise missile designed around a nuclear reactor.The spiking of radiation levels in the area, potentially reaching as far away as Norway, lends credibility to the theories.Putin’s spokesman, Dmitry Peskov, declined to confirm widespread international speculation that the accident involved a nuclear-powered cruise missile, but said the mishap would not set back Russian efforts to develop advanced military capabilities.Peskov said that only experts could speak with authority on such matters, but added: “Accidents, unfortunately, happen. They are tragedies. But in this particular case, it is important for us to remember those heroes who lost their lives in this accident.”Jon Hawkes, associate director of land warfare at Jane’s IHS Markit, said the system could work one of two ways. It could be an “air-breathing engine employing a small nuclear reactor core to heat incoming air that is expelled to generate thrust.” Or it could be a “nuclear thermal rocket engine, where the nuclear core is used to heat a liquid fuel such as hydrogen before expelling it through a nozzle to produce thrust.”‘Doomsday weapon’Yet he added, “given the Russians are claiming unlimited range, then one would assume it has to be along the lines of the first option, as the hydrogen fuel device would have a limit to its range.”The major problem with the 9M370, or SSC-X-9 Skyfall (as NATO calls it), is the exhaust. You can’t use a nuclear reactor to power a rocket without likely creating a form of dirty bomb on wings.”This is a doomsday weapon really,” said Dr Mark Galeotti, from Royal United Services Institute for Defence and Security Studies.”It’s not something that could be deployed in anything other than a full-scale nuclear war. It is a cruise missile that can stay in the air for a long time, but it is belching out radioactive plumes behind it.”The US indeed had a similar program in the 1960s, called Project Pluto, which was abandoned as they concluded it was too dangerous at the time.When Putin launched the missile with great fanfare in March 2018 he extolled its unlimited range — that it could circle the globe many times and then fire itself at its target from an unexpected angle, perhaps even days after launch.Is Putin bothered that it doesn’t appear so far to have worked that well? Not really, said Galeotti.”Vladimir Putin’s Russia is basically trying to puff itself up,” he said. “It is trying to look more militarily formidable than it is. Although they don’t like the fact that this failed, the fact that we are talking about the latest Russian military technology is definitely something of a plus.”US officials told CNN it’s been tested a few times, but never fully successfully. How far along the project is, and how big a setback this, is is anyone’s guess.A bad summerBut the Kremlin has had a number of incidents to brush off in the past month.In early July, the AS-31, or Losharik, super-deep, super-secret spy submarine, ran into trouble off the northern coast. State media said 14 sailors on board died of smoke inhalation, and the Kremlin insisted its nuclear reactor was intact when it was returned to port.The Losharik — named after a Soviet-era cartoon horse because of the compartmentalized components that enable it to dive to the bottom of the ocean floor — was meant to plunge to depths that nuclear and attack submarines could not. Again, Putin found himself being briefed on a clean-up operation.Weeks later, a munitions dump in Achinsk suffered a series of explosions over five hours, some causing devastating shockwaves and debris to be scattered over the area. A week later, local officials admitted forty people were injured.These three incidents amount to a bad summer for the Russian military, who after the invasion of Ukraine, and their intervention into Syria, had benefited from a short-term lift in their domestic prestige.Could over-reach be behind this recent spate of problems?Andrey Kortunov, Director General of the Russian International Affairs Council, said, “if you look at the current defense budget of the Russian Federation, it reached its peak in 2016.”He added it had decreased since.”So basically, the military and the defense sector are asked to do more for less,” he added, “and that might be a stretch. Maybe some of these accidents are a part of the price that the military has to pay from this relatively modest budget but the [substantial] ambitions behind this budget.”A turbulent month of unexpected blasts and leaks that begs the question as to whether the Kremlin’s race to the bottom of the sea, or top of the heavens, will scorch too much in its wake.