The shuttle landing gear are deployed 'mechanically.' As such they require a bit of a 'pop' to deploy just before contact with the runway. This is an intentional design safety feature. My father was the lead engineer on the shuttle autoland system. Much argument was made when he insisted the gear be deployed without hydrolics etc. As a former air force pilot he knew a major cause of landing crashes resulted from the failure of gear failure to deploy. The orbiter landing gear are manually deployed by the flight crew (Pilot or Commander). The orbiter approaches the runway at the steepest angle and highest speed of any known glider. You are correct that that there are no re-do's. Any failure of the landing gear to deploy properly will lead to a catastrophic failure. At about 220mph there is no room for ripping down the runway hoping the 'belly' of the aircraft will hold up.
On a related note the recent Endeavor mission had a quandary. IF the damage was severe enough to place the crew at great risk was it possible to land the orbiter without a crew? The answer is yes. The only barrier to autolanding the orbiter is deploying the gear and a mechanism to do so could have been devised if it had been needed. Thankfully it was not. The alternative risk of launching a 'rescue shuttle' was great; this time all turned out well.
We are still flying an experimental 'spaceplane.' One which has no viable escape system--the only craft ever built to take people into space without a crew escape system. The next generation vehicle should focus on crew safety, not payload capacity and as such can have a full crew escape system integrated from the outset. Shuttle's have always been envisioned as a way to ferry people to and from orbit safely, not cargo. Cargo can be handled by 'dumb' boosters. Max Faget, whom I had the honor of interviewing many times never did get to see the shuttle he designed go into operation.

Keith E. McInnis