Compared to the cost of losing a satellite or a shuttle to space debris impact, "this looks like a bargain, " says Dr. Campbell, who works at NASA's Marshall Space Flight Center in Huntsville, Ala.

WSJ: A Cosmic Question: How to Get Rid Of All That Orbiting Space Junk?

In the Dong Xuan Center, the lunchtime diners are primarily Vietnamese but the restaurants are also popular with students, hipsters and bargain-hunting wholesalers.

BBC: Berlin��s kitschy and flavourful Little Vietnam