Those types look EXACTLY like the ones you get on cheap radio control cars, not the 'proper' Tamiya ones (or similar good quality ones). If it's a NASA development project?, they got them off a cheap kids RC car (probably from one of the engineers little kids car!).
Take a peek under 'RC Biler / biltilbehør' and you'll find tires, maybe not NASA standard but of good quality. If you then go to the manufacturers homepages you may find an outlet in Denmark too.