US President Donald Trump’s ambitious plan to build a space-based missile defense system called the “Golden Dome” is drawing sharp criticism from defense analysts, scientists, and global powers, who warn the $175 billion project could be a technical dead-end and trigger a new nuclear arms race.Trump unveiled the plan last month, vowing that the United States would deploy an orbiting shield to intercept intercontinental ballistic missiles (ICBMs) from adversaries like China, Russia, or North Korea by the end of his proposed second term in 2029. The system, inspired by Israel’s Iron Dome, would be far more complex, designed to shoot down much larger, faster threats from across the globe.“Golden Dome will be capable of intercepting missiles even if they are launched from other sides of the world,” Trump claimed.But defense experts are deeply skeptical.“I’m not holding my breath,” said Thomas Withington, associate fellow at the Royal United Services Institute (RUSI). “The challenges are so significant at this stage that they may simply be unrealistic within the timeframes that the Trump administration envisages.”Space lasers and satellite swarmsThe proposed system would rely on detecting missiles during their “boost phase” — the initial minutes after launch when the rocket is most visible from space. But to successfully intercept a single ICBM during this window, hundreds of interceptor satellites would need to be in constant orbit.“It would take about 950 interceptors in orbit to ensure at least one is always in range,” said Todd Harrison from the American Enterprise Institute. “To counter a salvo of 10 missiles, you’d need nearly 9,500 interceptors.”The US Congressional Budget Office has estimated that even a limited version of the system, designed to stop just one or two ICBMs, would cost between $161 billion and $542 billion.The plan also includes space-based lasers to destroy missiles without generating debris. But European defense contractors say such capabilities are “still beyond what even the Americans are capable of doing.”“It’s just an excellent way to give the US defense industry substantial funding,” one anonymous contractor told reporters, “without necessarily aiming for actual deployment.”Risk of a global arms raceCritics also warn of geopolitical fallout. Analysts say the system could threaten the principle of mutually assured destruction, which underpins global nuclear stability.“If Washington is perceived to be developing a shield that could one day neutralize a retaliatory nuclear strike, it risks triggering a dangerous global arms race,” said Julia Cournoyer, a research associate at Chatham House.China, Russia, and North Korea have already condemned the plan. Beijing and Moscow called it “deeply destabilizing,” while Pyongyang labelled it “very dangerous.”The concept echoes Ronald Reagan’s 1980s Strategic Defense Initiative, which also envisioned satellite interceptors but was ultimately scrapped due to cost and feasibility concerns.Still, some speculate Trump may be using the proposal as a bargaining chip in future arms control talks.“It may be that the Trump administration hopes to bring China and Russia to the table to negotiate nuclear reductions or revive arms control dialogue,” said Withington.