Why? If the Centaur is in fact at fault for the Titan failure, the Pratt and Whitney RL-10 system may be involved. The Delta III also uses the RL-10 as its upper stage engine system. But that delay may also effect the smaller Delta II, which does not fly with the RL-10.

To launch the Delta II/FUSE now set for May 27th, the Delta III must launch to clear that pad. The other Delta pad at Cape Canaveral is occupied with the Air Force Delta II/GPS IIR-3, now set for May 23rd. Thus if the RL-10 grounds the Delta III, it may block other manifested Delta IIs from their shot at its pad.

And should RL-10 questions keep the Delta III on the ground, it may also effect the Atlas III program-whose upper stage is also RL-10 based. The next commercial Atlas launch is set for May 15th, leaving precious little time for any major change to the engine system as a result of the Titan mishap.

Once again, the close interrelationship among U.S. launch vehicle designs shows both the strengths and possible weaknesses of the American space fleet.

And it is also a reminder that with so few new designs for upper stages, the U.S. still must rely for heavy lift on the Boeing IUS and Lockheed Martin Centaur-both designed long years ago for original missions long completed.

Moreover, with a robust Delta launch schedule on the books, lengthy delays in the larger Delta III could threaten the Delta II order book-for there are only so many pads to launch the vehicles.

In fact, 1999 may be shaping up as the worst year in recent memory for the expendable launch vehicle business. With the Titan losses, upper stage woes, Delta and Atlas schedules in doubt, even the much vaunted French are staying too long on the ground- not because of launcher problems, but because of payload and payload delivery issues - in effect "manifest management".

Against this entire backdrop, the U.S. Congress and White House are finally coming to terms with serious space launch range issues that have been long delayed: range upgrades, modernization, and above all ratification of the U.S. government's 3rd party liability legislation for perhaps another six to 10 years.

If space launch is the engine that helps drive commercial space growth, the entire industry has a stake in settling the problems represented by today's Titan IVB mishap. For the road to space to be widely used, it must offer clear lanes of travel.