NASA exploring ways to keep International Space Station afloat without Russia

NASAisexploringwaystokeeptheInternational Space Stationin orbitwithoutRussianhelp, but doesn't see any immediate signs Moscow is withdrawing from the collaboration following the invasion of Ukraine, a seniorofficialsaid Monday.

Kathy Lueders, who heads the agency's human spaceflight program, told reporters on a call that operations on the research platform were proceeding "nominally" and "we're not gettinganyindications at a working level that our counterparts are not committed."

"That said, we always look for how do we get more operational flexibility and our cargo providers are looking at how do we add different capabilities," she continued.

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While the US side of the ISS supplies power and life support, Russia is responsible for propulsion and keeping thestationafloat: it does this by using docked Progress spacecraft to periodically give thestationa boost to maintain its altitude, approximately 250 miles (400 kilometers) high.

Last week, though, Russia'sspacechief Dmitry Rogozin raised the prospect of pulling out of the partnership in response to US sanctions, allowing the 400 ton structure to come crashing down to Earth while most likely avoiding his country, since itsorbitdoesn'tfly much over it.

Lueders said: "Northrop Grumman has been offering up a reboost capability, and you know, our SpaceX folks are looking at can we have additional capability."

The last Northrop Grumman Cygnus cargo vessel that arrived at the ISS on February 21 was the first to boast a capacity to "reboost" the outpostwithoutRussianhelp.

On Friday, SpaceX boss Elon Musk tweeted his company's logo in response to Rogozin's rhetorical question about who would save the ISSfroman uncontrolled de-orbit.

But Lueders stressed that such plans were a contingency measure only.

"It would be very difficult for us to be operating on our own -- ISS is aninternationalpartnership that was created...with joint dependencies," she said.

"As a team, we are looking at where we may have operational flexibilities, but... it would be a sad day forinternationaloperations if we can'tcontinue to peacefully operate inspace," she concluded.

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A symbol of post Cold War detente, the ISS has been continuously habited for more than 21 years and has weathered past geopolitical storms, notably Russia'sinvasionof Crimea in 2014. But some observers believe theinvasionofUkrainecould hasten the demise of US-Russianspacecooperation.