You are not alone if something fails to work on your
rocket
Rocket development failures
The
most important thing is to identify why systems or lack of procedures
contributed to the failure.
Quotation:
' Space disasters have occurred for the most diverse
reasons and on different scales, both in the Soviet Union and the United States.
In all the cases I am familiar with the common factor is that those who were
truly to blame for the disaster remained alive and faced no censure
'
Boris
Chertok
Russian Space
Academician.
Article taken from the US Design News 1999
U.S. faces space-launcher stand down
By Rick DeMeis, Senior Editor
Washington--Not since 1986, with the
Challenger accident and concurrent failures of Titan, Atlas, and Delta II
rockets, has the U.S. confronted a stand down of a large portion of its booster
fleet. While the shuttle has been made more reliable, since last summer six
launches of expendable boosters have failed. President Clinton asked Secretary
of Defense William Cohen to fathom out "root causes behind the recent
failures and take corrective action." His final report is due around
Thanksgiving.
Here's a run down of this losing streak:
August 19, 1998: wiring damage causes a solid rocket booster on a
Lockheed Martin Titan IV to explode, destroying a classified communications
satellite.
August 26, 1998: a first-stage guidance design flaw causes an
unprogrammed maneuver, over-stressing a Boeing Delta III on its maiden
flight with loss of a commercial Galaxy communications satellite.
April 9, 1999: incomplete stage separation on a Boeing Inertial Upper
Stage places a missile-warning satellite launched by a Titan IV into an
unuseable orbit.
April 27, 1999: a nose cone fails to separate from a small Lockheed
Martin Athena booster, and its commercial Earth-imaging satellite payload
plunges back into the atmosphere.
April 30, 1999: a black hat trick for Titan IV missions when improper
software in a Centaur upper stage places a Milstar communications satellite
in a useless, lower-than-geosynchronous orbit.
May 4, 1999: early shut down of a Delta III upper stage, using an
advanced version of the Centaur engine, leaves an Orion communications
satellite stranded in a low orbit.
Root causes. While seemingly unrelated, experts are looking for common
trends. Causes mentioned include: more reliance on computer modeling rather than
full, all-up booster testing; over-emphasis on lowering booster costs, perhaps
prompting short cuts; and fewer middle-age, more experienced aerospace
engineers, leading to a loss in industry "corporate memory."
One of these seasoned veterans of the Rocket Mafia toldDesign Newsthat, "fewer launches today on each booster make it harder to keep
workforce morale and skills up. The failures are random. It doesn't seem to be a
design problem, but quality control and human error--just not doing things
right--and should be traced.
My Note: Experience counts! Even if you are the wrong side of fifty.
The challenger disaster could have been
avoided if the advice of one of the engineers responsible for the solid boosters
had been listened to.
He predicted failure of the booster
segment ring 'O' ring seals at low temperature launch. The rest is history....
USSR Tyuratam, Nedelin R-16 Disaster On October 26,
1960 Between the official 74 and the actual figure which is now
estimated to be closer to 200
soldiers and technicians died after an explosion at the inaugural R16
launch site. When the second stage of
the rocket was accidently ignited 30 mins before the planned launch.
This was a hastily arranged prototype rocket launch
undertaken with numerous known problems unresolved
Channel 4 Challenger: Countdown to disaster
The tragedy was the result of a faulty O-ring seal used to seal between the
solid booster segment rings. During very low temperature launch conditions. This
had been predicted by some of the older engineers at Morton Thiokol, responsible
for the construction of the solid rocket booster. Who tried to prevent the
launch of the shuttle at low temperatures. There warning was ignored both by
there own company and NASA management teams.
After launch on an exceptionally cold morning the seals failed 73
seconds after lift-off and allowed the white-hot exhaust gases from Challenger's
huge launch rockets to penetrate its booster rocket mountings – and ultimately
to ignite the main fuel tank.
Dec 2002 Initial test flight
of the heavy lift Ariane 5 ECA
Vulcan 2 nozzle
failed at altitude due to low atmospheric pressure outside the nozzle
causing the bell shaped expansion nozzle to deform. The resulting reduced thrust
and localised heat transfer problems triggered the abortion of the inaugural
flight.
Inadequate development
testing was identified as one of the principle causes for this flight failure.
Improved cooling and
stiffening of the nozzle that was then proved during numerous static
engine test fiirings resolved the problem.
One of the keys to becoming a good engineer or research
scientist if being able to analyse all the multiple causal parameters that
contribute to a system failure.
As an investigator you need to be capable of staying
independent and impartial.
A cool clear open minded approach is essential.
Remember there is no good time for the truth. It take courage
and professional integrity.
10.01.2003
Death of a Blackbird
Low temperature failure at -7C.
Combined with high number of launches fatiging the bonded joint line
between bottle and fin.
Note the milky coloured wax
like appearance
of the adhesive.
When you notice that the adhesive
is changing in colour replace the adhesive and and if the bottle
appears to be damaged replace the bottle
26.04.2003
Here the fine tie cord linking the coiffe with the base plate
was too short and restricted the freedom of the nose cone to seperate
properly from the base-plate.
10.03.2003
Here a raised platform is added to the baseplate to
prevent the packed parachute from interfering with the pressure
equlisation between interior and exterior of the rocket.
23.6.2003
Initially we had problems with the
nose cone being forced down over the main diameter of the rocket body
due to high launch acceleration loads.
We seemed to encounter problems
that other people never had!
So we introduced the pressure
equalising hard shoulder shock plate
that was just marginally larger
than the base of the nose cone.
Up to 8bar the early type of nose
cone worked well.
Then all of a sudden it started to
fail. Why?
Four failures in a row. Analysis
of why these flights failed led to the success of the fifth using a
modified coiffe ring. To stiffen the base of the nose cone under higher
pressure launch loading.
10.01.2003
26.04.2003
10.03.2003
23.6.2003