From: raymond@jupiter.ame.arizona.edu (Raymond Man)
Newsgroups: soc.culture.china
Subject: CHINESE ROCKET SHROUD BREAKUP CAUSED LONG MARCH FAILURE
Date: 26 Jan 93 18:02:13 GMT
Distribution: world,local
Organization: University of Arizona, Tucson
Originator: raymond@jupiter

CHINESE ROCKET SHROUD BREAKUP CAUSED LONG MARCH FAILURE
Craig Covault/Paris, Aviation Week & Space Technology, Jan. 18, 1993

The Catastrophic breakup of the Chinese-built launch shroud on the
Long March 2E booster, which carried the Hughes/Optus B2 spacecraft,
caused the mission failure and satellite loss.
  Analysis of debris, telemetry and photographic evidence shows that
the Dec. 22 failure was caused by a problem with the Chinese booster,
not the Hughes 601 spacecraft, U.S. and European sources told
AVIATION WEEK & SPACE TECHNOLOGY.
  China has yet to accept blame for the accident, and a Chinese
Aerospace Ministry official last week still denied that the booster
was to blame (AW&ST Jan. 11, p. 60). But data from the accident show
a failure of the nose shroud triggered the accident.
  Sources told Aviation Week the accident occurred when the Chinese-
built 4.2-meter-dia. (13.8 ft.) nose cone shroud covering the satellite
broke up while the vehicle was reaching supersonic velocity at about
23,000 ft., 45 sec. after liftoff.
  This is the ascent regime, when the greatest aerodynamic pressure and
structural loading--Max Q--are exerted on the booster.
  When the shroud ripped away, the Hughes satellite was exposed to a
1,000-mph. slipstream that destroyed it.
  A flash seen by ground observers at this moment is thought to have been
caused by a small explosion resulting from liquid propellants used by
the spacecraft for geosynchronous orbit station-keeping being mixed as
the satellite was destroyed.
  The nose shroud was not supposed to separate from the Long March until
nearly 4 min. into the flight. The vehicle at that point would have been
at nearly 300,000 ft. (57 mi.) altitude, and above most of Earth's
atmosphere.
  Even though the shroud opened too early and the satellite was destroyed,
the remaining upper section of the booster was strong enough structurally
to sustain the booster's flight. The Long March upper stage entered orbit
as palnned, but without its several-hundred-million-dollar payload.
  Why the Chinese shroud failed is yet to be determined. But the
investigation is focusing on what Chinese technicians did to the shroud
when opening and closing the unit before launch.
  The shroud was closed with the satellite inside, but then reopened so
Hughes technicians could replace an avionics system in the spacecraft.
Such operations are not unusual in launch preparations.
  Weatern engineers believe the shroud then was released improperly or
that a "small modification" was made to it by the Chinese. They said this
was not reviewed with Hughes and could have been a factor in the accident.
  The accident will hurt China's ability to market the Long March
commercially against the European Ariane, Russian Proton and U.S. Atlas.
An Atlas suffered a similar failure that destroyed a U.S. Defense Dept.
satellite several years ago at Cape Cananveral.

-----End of Unathorized copy from AW&ST-----typos may be introduced by psoter--

Please, Mr. Covault, don't sue me. I am poor.
-- 
Just call me `Man'. 
"And why take ye thought for "    --   Matt. 6:28
raymond@jupiter.ame.arizona.edu
Newsgroups: soc.culture.china