A beefed-up missile defense system might seem like a good idea in a time of heightened nuclear tensions. But such enhancements could have dangerous consequences.

The current U.S. missile defense system isn’t all it was cracked up to be, performing unreliably in tests, physicist and missile defense expert Laura Grego argued April 14 at a meeting of the American Physical Society. Enhancing the system’s power, however, by building missile defense in space, for example, might put the world on a slippery slope to space warfare, she warned.

The worries come against the backdrop of North Korea’s nuclear weapons and missile tests (SN: 8/5/17, p. 18) and an upcoming missile defense review from the U.S. Department of Defense, expected in May. That review could accelerate efforts to revamp the current system, including schemes to strike at missiles from space.

“Missile defense is once again having its day,” said Grego, of the Union of Concerned Scientists in Cambridge, Mass., at a news conference.

Boosted by a rocket engine, a ballistic missile sails into space before releasing a warhead that plummets to its target under the force of gravity. Missile defense systems are designed to shoot down such missiles in flight. But today’s technology doesn’t fully protect the United States. Tests of the country’s system have literally been hit or miss, sometimes succeeding and sometimes failing to intercept the target.

Although not specifically designed for it, a system capable of stopping intercontinental ballistic missiles can also be used to destroy satellites, since some satellites travel at altitudes and speeds comparable with those of missiles. There’s some precedent for this: In 2008, the United States shot down one of its satellites, which was malfunctioning. Likewise, China demolished one of its fleet in 2007. So if countries around the world start ramping up their missile defense, that could have the world tiptoeing closer to space warfare.

Using such antisatellite weapons could have major repercussions, including creating long-lasting space debris that could damage spacecraft (SN Online: 8/15/11). “If you ever expect to use space again, you don’t start blowing things up in space,” Grego said.

To read more, click here.