Commercial Titan

In September 1986, after it had been decided to prohibit the Shuttle from deploying commercial satellites, Martin Marietta announced that in 1989 it would make available a new version of the Titan 34D with a lengthened second stage and an enlarged shroud to carry satellites that had been developed for the Shuttle.96 This Commercial Titan could accommodate various third stages depending on the payload requirements, including the PAM, an IUS, a Centaur G-Prime (developed for Shuttle payloads) and the new Transfer Orbit Stage (TOS). The Titan was expensive to operate, but the fact that it could accommodate a heavy load meant that if it was fitted with a dispenser it would be able to deploy a pair of satellites and the cost shared between the customers. In addition, it was offered to the Air Force as a Medium Launch Vehicle, but this contract (which was issued in January 1987) went to McDonnell Douglas. Martin Marietta soon secured 10 launch options.97 Commercial Titan Incorporated was formed in May 1987, and negotiated an agreement with the Air Force for launch services from Pad 40 at Canaveral.

The introduction of the Commercial Titan was good news for the owners of oversized satellites. As with the HS-381, the Hughes HS-393 (at that time the largest commercial communications satellite) had been designed to exploit the width of the

The launch of an Atlas IIA on 30 June 2000 with TDRS 8.
The launch of an Atlas HAS on 18 September 2002 with Hispasat ID.

Shuttle's bay, but it was considerably taller than the HS-381, and had upgraded HS-376-type transponders that could relay up to 120,000 telephone calls simultaneously. Intelsat had ordered six and booked them on the Shuttle, but after the loss of Challenger it had to await the introduction of either the Ariane 4 or the Commercial Titan.98 Japan was in the same predicament, with two satellites. Japan's JCSAT 1 was launched on an Ariane 4 on 6 March 1989, and the first of the Intelsat 6 series followed on 27 October 1989. The first Commercial Titan on 1 January 1990 deployed Skynet 4A for the British military and JCSAT 2. For the second Commercial Titan, however, the dispenser's control system was set as if it had two satellites, whereas it had only one, and the firing command was sent to one pyro cable with the separation system connected to the other! The result was that on 14 March 1990 it failed to release Intelsat 603 (also known as 6F3).99 To prevent the satellite being dragged back into the atmosphere along with the spent stage, it was ordered to separate from the trapped Orbus perigee kick motor and fire its own thrusters to raise its orbit. Even although the valuable satellite was stranded in low orbit, it was at least in space, and if a Shuttle crew could attach another motor it should be able to attain geostationary orbit. NASA was therefore invited to rescue a satellite that it was originally to have dispatched. Meanwhile, on 23 June 1990 the third Commercial Titan successfully deployed Intelsat 6F4.

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