bbc@titan.rice.edu (Benjamin Chase) (03/26/88)
(Please be patient with my first posting...)
Excerpts from an article appearing in the Houston Chronicle, 25 March 1988
Vetco Gray Inc., a venerable Houston oil field equipment company, is quietly
making a mark in the aerospace business with its work on backup designs for
two critical areas of the space shuttle's sold fuel rocket boosters. Within
weeks after the January 1986 Challenger accident, Frank Adamek, program
manager for the company's aerospace division, proposed unsolicited
modifications of the booster's field and case-to-nozzle joints. Vetco Gray
has also presented its T-seal and U-seal designs to aerospace companies
competing for a future NASA contract to produce an advanced solid rocket
motor for the shuttle. Adamak said there may be other markets, including
such commercial unmanned solid rockets as the Conestoga developed by Space
Services Inc. of Houston for small payloads.
"It's an uphill battle," Adamek admitted, "because we are in effect touting
a technology that is new in the oil industry and state of the art for
aerospace." The Thermalok seals have the backing of at least one key
outsider, Roger Boisjoly, the former Thiokol engineer who attempted to halt
the Challenger launch, believes both the T-seal and U-seal are superior to
the current redesigns.
The Vetco Gray proposals, which incorporates metal-to-metal seals developed
initially for the high temperature, high pressure environment of oil well
drilling and production, have been carried along as backups to the
NASA-Thiokol modifications. "We were somewhat disappointed", Adamek said of
the backup role. "I think the technology is there. Their point of concern
was timing. The baseline (NASA-Thiokol) design had a several month lead
time." The patented designs are referred to as the Thermalok T-seal for the
field joint and the Thermalok U-seal for the case-to-nozzle joint.
If pressed into service as the alternate, the T-seal in the field joint
would be joined by a Teflon rather than a rubber primary O-ring. A Viton
rubber O-ring would provide a secondary seal. The capture feature O-ring in
the current redesign would be removed. The Thermalok T-seal passed an
assembly and pressure check test overseen by Thiokol officials at Vetco Gray
facilities in Houston last fall. A minor pressure leak was detected, but
Adamek said it was attributed to some roughness on the inner surface of a
booster segment. An actual ground test firing of booster components with
the Thermalok T-seal this year was canceled after test successes last year
and budget constraints.
Ben Chase bbc@rice.edu (713)-527-6012