This is the best summary I could come up with:

Hypersonic refers to missiles that can travel at extremely high speeds and also change direction during flight, evading air defences.Russia says it has used two types in its war on Ukraine – the Kinzhal, launched from an aircraft, and the Zircon cruise missile.However, Kyiv says its forces have shot down some Kinzhal missiles, raising questions about their capabilities.As the technology has been developed and deployed, the arrests have continued.Shortly after Mr Galkin’s arrest in April 2023, he was remanded in court on the same day as another scientist, Valery Zvegintsev, with whom he had co-authored several papers.The state-owned news agency Tass has cited a source saying Mr Zvegintsev’s arrest may have been prompted by an article published in an Iranian journal in 2021.

“Hypersonic is a topic you are now obliged to put people in jail for,” says Yevgeny Smirnov, a lawyer with First Division, a Russian human rights and legal organisation.Mr Smirnov defended scientists and others accused of treason in court before he moved from Russia to Prague in 2021, fearing repercussions from his work.He says none of the dozen scientists had anything to do with the defence sector, but were studying scientific questions such as how metals deform at hypersonic speeds or the effects of turbulence.

“This is not about making a rocket, but about the study of physical processes,” he says, and points out that findings may be used later by weapons developers.The arrests had started a few years earlier with Vladimir Lapygin.

Other cases are also understood to relate to international collaboration.An investigation into two other scientists was related to Hexafly, a European project to develop a hypersonic civilian aircraft, according to the lawyer Mr Smirnov, who worked on the case.That project, now finished, was led by the European Space Agency and began in 2012.The agency told the BBC “all technical contributions and exchanges were agreed and foreseen” in a co-operation agreement between the Russian and European parties involved.Both scientists were sentenced to 12 years in prison last year, though Russia’s Supreme Court has ordered a retrial of one of them.Other arrests related to a study into the aerodynamics as a space vehicle re-enters Earth’s atmosphere.It was funded by a European Union scheme and run by the von Karman Institute of Fluid Dynamics in Belgium.FSB investigators were concerned about a rounded cone shape that looked like a warhead in research that one of the scientists, Viktor Kudryavtsev, sent to the von Karman Institute, according to his widow, Olga.The institute says the programme, which ran from 2011 to 2013, “very clearly excluded military research”.

Human rights groups see a pattern.Mr Smirnov says that, in private conversations, FSB officers have admitted to him that cases about sharing hypersonic secrets were being opened “to satisfy the wishes of those higher up”.He believes the FSB wants to give the impression that spies are hunting Russian missile secrets “to flatter the ego” of Mr Putin.The cases come amid a wider rise in treason cases.Sergei Davidis, who leads work supporting Russian political prisoners at the Memorial human rights centre, speaks of an “atmosphere of spy mania and isolationism”, especially since Russia’s full-scale invasion of Ukraine.Speaking from Lithuania, where his organisation moved after it was banned in Russia, Mr Davidis says he believes the FSB, keen to show it is delivering, “builds up its reporting statistics through the fabrication of cases”.But he believes there may be other factors in the arrests of scientists, such as competition for state contracts, or even a Kremlin message of dissatisfaction aimed at all scientists involved in hypersonics.Mr Smirnov says the FSB sometimes offers more lenient sentences if suspects confess and implicate others.Kudryavtsev was offered a plea bargain under which he would admit guilt and point the finger at someone else, according to his widow, Olga.He refused.

Retired FSB General Alexander Mikhailov says the FSB “must ensure the confidentiality” of military technology.He says “undoubtedly” that there must be “substantial grounds” for severe sentences such as the 14-year prison term handed down in May to one of the three ITAM scientists, Anatoly Maslov.Gen Mikhailov says the current spike in treason cases is the product of the expansion of freedoms and democracy in the 1990s.He says this led to a change in attitude from Soviet times, when he says those with access to state secrets were “thoroughly vetted” and “understood the responsibility” of disclosing them.

The original article contains 1,598 words, the summary contains 725 words. Saved 55%. I’m a bot and I’m open source!

Wow! How did they catch him? With a super-duper-sonic net?