Russia-West scientific collaboration that bloomed in the aftermath of the Cold War has been quickly scrapped.

For neuroscience researcher Boris, "everything fell apart" a month ago, when Russia's invasion of Ukraine sent decades-long scientific cooperation with the West crashing back to Earth.

In response to sanctions and moral outrage at Moscow's war, scientific institutes around the world swiftly cut off ties with Russia, including the European Space Agency, the European Organization for Nuclear Research (CERN) and leading US university MIT.

International scientific collaboration that had long symbolised the world coming together in the aftermath of the Cold War—particularly in space—suddenly had to be scrapped, sending many projects back to the .

When the European Space Agency's director general Josef Aschbacher announced the end of cooperation with Russia, he called it an "agonising decision".

The decision spelled a long postponement for the ExoMars mission, which had planned to use a Russian rocket to put a European rover on Mars later this year to drill for .

Aschbacher said a launch was no longer possible until at least 2026—and that the ESA could now look to NASA for help.

It was as a huge blow for the thousands of scientists in Europe and Russia who had been working on the project for years—and came after ExoMars had already been postponed for two years by the Covid-19 pandemic.

Europe's Rosalind Franklin will no longer take a ride on a Russian rocket this year to search for life on Mars.

'Cut off from the world'

For Boris, an American of Russian origin living in France who did want to give his surname, 10 years of work was lost overnight when Russia invaded Ukraine on February 24.

He said he had founded a research centre in Russia to create "a unique cross-border model in the field of neuroscience", in which Russian students could travel to different laboratories across Europe.

He told AFP the project has not been officially cancelled, but "everything is blocked," in part because PhD students in Russia can no longer pay for their work due to financial sanctions.

Other students have fled Russia after being threatened with being arrested for protesting against the war.

"We talk to each other every day via Skype or Zoom... but we are lost, the war is beyond us," said Boris, whose parents left the USSR in the 1980s as Russia waged war on Afghanistan.

"For students who have not experienced the Soviet era, it is unimaginable to live in a country cut off from the world. They were truly European in their minds."

Nearly 8,000 Russian scientists and academics signed an open letter earlier this month condemning the war after the International Congress of Mathematicians scheduled to be held in Saint Petersburg in July was called off.

"The many years spent strengthening Russia's reputation as a leading centre of mathematics have been completely scuppered," the letter said, calling Russia "the military aggressor and, accordingly, a rogue state".

The influential Russian Academy of Sciences has "called for a cessation of hostilities and urged foreign researchers to avoid a breakdown in scientific relations"

'Complete boycott' demand

The influential Russian Academy of Sciences has "called for a cessation of hostilities and addressed foreign researchers to avoid a breakdown in scientific relations," said Carole Sigman, a researcher at France's National Centre for Scientific Research—which has also suspended collaboration with Russia.

She said there had been an influx of requests for visas from Russian scientists to come to France—as well as scientists from Ukraine and Belarus.

Several professors from renowned US universities including Harvard and Cambridge have called on "science and technology communities to avoid shunning all Russian scientists for the actions of the Russian government".

While condemning Russia's "brutal, unprovoked war", the professors said in an published in the Science journal on Thursday that shutting down all interactions with Russian scientists "would be a serious setback to a variety of Western and global interests and values".

But for many Ukrainian scientists plunged into war, the world cutting off research collaboration with Russia is essential.

Maksym Strikha, a physicist from the Taras Shevchenko National University of Kyiv, told Nature earlier this month that "there should be a complete boycott of the Russian academic community. No cooperation".