The Space Centre is a building entirely driven by science, emerging as an idea from the space scientists of the University of Leicester. It is one of the new generation of interactive science centres, concerned not only with rockets and satellites and space travel, but more widely with our whole place in the Cosmos. All you really need to house such schoolchild-friendly exhibits is a big windowless black box. Most of the Space Centre is just such a box, sunk into the ground and clad in perforated stainless steel. Its flat roof is broken only by the shallow dome of a planetarium beneath. But that's not enough, these days. To attract both the Millennium Commission funds and the customers, you need to build a landmark. Enter the Maggot.

It is a squat, curvaceous 140-foot tower rising from one corner of the box. It contains two real rockets, both early satellite launchers, one a failure, one a success. Guess which is British and which is American. Side by side, then, you have a real British "Blue Streak" and a real American "Thor Able". Blue Streak was one of those many 1950s-originated aerospace gizmos with which Britain was going to lead the world, but then found it politically expedient not to be able to afford. Originally conceived as a ballistic missile, it was then going to be the first stage of a European satellite launch vehicle. Of course we took years too long over it and then pulled out, so the French took over, produced the Ariane rocket series instead, and reaped great reward. Meanwhile the American military got Thor into production in a few months, and rapidly added the Able upper stage: another big success for someone else.

Blue Streak looks much more interesting: an intricate, lovingly crafted stainless-steel space vehicle. Next to it, Thor Able looks exactly like many of the white-painted metal factory chimneys dotted around this industrial suburb of Leicester. Dull in the extreme. Grimshaw's architecture here comes from the Blue Streak school. It is fascinated by its own ingenuity, it is anything but boring, it is technologically advanced. And it is just a bit too clever for its own good.