The Astro is actually a pretty robust vehicle having a solid frame underneath it. It suffers from the design issue as othee vans, mini or nowt, that the driver and passenger sit somewhat on top of the front wheels instead of behind them making the front crumple zones smaller.
But as others have said, its in a different weight class. The Astro shared a lot of basic design and parts with the S series trucks which were 1/4 ton trucks. The 1500 and 150 class of trucks and vans are 1/2 ton, the 2500/250 are 3/4 ton and the 3500/350 are 1 ton so you have a much larger heavier vehicle.