On 30 October 2001, the University of Queensland Department of
Mechanical Engineering (UQ), launched an experimental
supersonic-combustion ram jet (scramjet) payload via a two-stage
solid-fuel rocket that was provided by Astrotech Space Operations
Inc (Astrotech). The rocket was launched from the Woomera
Prohibited Area in northern South Australia, that was operated by
the Department of Defence (DoD). The planned flight was to validate
data obtained in the hypersonic wind tunnel at the UQ
facilities.
The launch occurred at 1301 Australian Central Summer Time and
according to observers and video evidence, the first stage booster
appeared to operate successfully, although UQ personnel noted an
anomaly in the received telemetry data. After the initial coast
stage, during which time the first stage separated, the second
stage ignited and observers reported seeing the rocket and the
resultant exhaust trails appearing to curl in a 'cork screw'
fashion. That continued with the stability of the rocket appearing
to deteriorate until it was out of sight.
The first stage (Terrier) was recovered from the intended impact
area shortly after the flight, while remnants of the first stage
fixed fins were recovered north east of the flight path and between
the first stage impact area and the launch pad approximately 12
weeks after the launch. The separate location of the fins indicated
that the fins separated from the vehicle during the first stage
flight.
The second stage (Orion) with fixed fins and payload was
recovered about 16 weeks after the launch from an area about 28 km
east of the Stuart Highway and about 100 km north west from the
launch site rather than the 373 km nominal aiming point. The
highway had not been closed to traffic, nor was it required to
be.
After the flight, the UQ team reported that while examining
their telemetry data they noted an anomaly in the accelerometer and
magnetometer data at approximately 2.8 seconds after first stage
ignition. UQ also noted that the vehicle had not achieved the spin
rate (4-6Hz) that was intended. However, the UQ team suggested that
the low spin rate was more likely the result of some other event,
perhaps the loss of one or more fins, rather than contributing to
the accident. Additionally, a number of personnel who viewed the
post-flight video reported seeing what appeared to be objects
falling from the vehicle during the first stage burn. However, the
Optical Coordinator from the launch team and Australian Transport
Safety Bureau (ATSB) investigators considered that the video images
lacked sufficient resolution to determine what occurred at those
times.
ATSB specialist examination of the first stage indicated that
the fixed fin support structure had broken up during the flight.
Examination of the fracture surfaces indicated overload through the
fixed fin spindle (journal) sockets. Larger Nike fins had been
fitted by Astrotech rather than the smaller standard Terrier fins.
This was to achieve the required stability and ensure a stable
platform during the scramjet experiment. No pre-existing defects
were found within the physical structure of the fin support. Some
of the fin journal sockets showed evidence of excessive angular
bending forces, suggesting possible movement or rotation of the
fins during flight. A considerable proportion of the first stage
fixed fin skin and internal honeycomb material had not been
recovered at the time the investigation was carried out. Of the
material that was recovered, most of the damage and deformation
suggested both aerodynamic and ground impact forces.
The Nike fixed fin angle of incidence was adjusted using
trailing edge adjustment lugs. Marks and damage around the fixed
fin adjustment lug mounting points indicated in-flight movement and
possible insecurity of the fin adjustment lugs. Crushing damage of
the fin rib sections beneath the lug mounting set-screws was
possibly pre-flight damage which may have contributed to in-flight
movement. It was also noted that the Nike fins were not designed
for securing in the location used and contained no reinforcement or
other strengthening features in this area. The Nike fins were
designed to be secured on the leading side of the fin base, whereas
the original Terrier fins were designed to be secured on the
trailing side of the fin base.
ATSB specialist examination of the payload found no evidence to
suggest that the payload or associated components had contributed
to the flight anomaly, however the level of impact damage limited
the examination.
During launch preparation, sandbags were placed around the base
of the launcher. The Astrotech "Operation and Inspection Log for
the Assembly of the Terrier-Orion Suborbital Launch vehicle system"
called for grout to be placed at the base of the launcher. However,
grout was not available, thus sandbags were used to protect the
base of the launcher. UQ suggested that it was possible that a
sandbag or a rock in a sandbag could have damaged a fin during the
initial launch phase. That would have required a sandbag or rock to
have been deflected off the infrastructure and impact a fin. Video
footage and still images viewed by the ATSB Specialists and
Astrotech, indicated that a number of the sandbags were ejected
and/or disrupted during the ignition and launch. However, it was
not possible to determine if a rock had impacted a fin during the
launch sequence.
The examination could not conclusively determine what caused or
allowed the first stage Nike fixed fins to move during the flight.
However, based on the available evidence, it is likely that the
first stage Nike fins either sustained damage from aerodynamic
overload due to their movement during the flight or the fin support
structure was unable to support the increased aerodynamic load of
the larger Nike fins. It is also possible that the sandbags or
rocks ejected during the launch damaged the first stage fixed fins.
As a result, at separation, the second stage would have been in an
unstable flight attitude and possibly not able to recover
stabilised flight.
Because the Space Activities Act and Space Activities
Regulations did not provide for a launch licensing instrument with
a fee structure appropriate to the resources of
educational/scientific organisations, UQ was granted an exemption
certificate by the then Minister following a recommendation from
the Australian regulator, the Space Licensing and Safety Office
(SLASO). As part of UQ's application for an exemption certificate,
it was required to furnish a risk hazard analysis of the project
based on statutory methodology and informal guidance provided by
SLASO.
The investigation determined that although the risk analysis
conducted by UQ allowed for failure of the first stage and non
ignition of the second stage, insufficient allowance was made for
the rocket vehicle malfunctioning and going off course. During the
investigation, UQ indicated that as part of its hazard
identification during the risk hazard analysis process, it had not
specifically considered the possibility of the rocket impacting
near the Stuart Highway. The second stage and payload impacted
about 28 kilometres east of the highway.
Although SLASO had expressed reservations in an internal
document, prior to the launch, regarding the risk hazard analysis
submitted by UQ, it assessed the analysis as part of the
application and recommended that UQ be granted the exemption
certificate. SLASO was satisfied that a risk hazard analysis has
been performed and that the launch would comply with the Launch
Safety Standards of the Flight Safety Code , provided there were
adequate exclusion arrangements for the WIR and the area around the
nominal aiming point. As part of that assessment, SLASO also
relied, in part, on the granting of a licence to Astrotech by the
United States regulator, the Federal Aviation Administration (FAA),
the submission of a risk hazard analysis to the FAA by Astrotech as
part of their launch licence application and an analysis conducted
by the FAA. Although SLASO requested a copy of that analysis from
the US regulator, it was not provided. After the Launch, SLASO
commented that there was no evidence that the launch violated the
risk acceptance criterion spelled out in the launch safety
standards of the Flight Safety Code.
SLASO is seeking to acquire specialist risk analysis software,
with appropriate user training, to assist with assessing risk
hazard analysis models submitted by applicants. SLASO also
indicated that it plans to provide additional guidance for
applicants wishing to apply for a licence, permit or exemption
certificate. Additionally, Government approval has been granted to
amend the Space Activities Act to provide for educational/research
activities with an appropriate fee structure. That will allow the
requirements to be clearly spelt out in regulations made in respect
of that certificate.
UQ has indicated that it intends to reassess its risk hazard
analysis.
Astrotech indicated that it plans to review its pre-launch
assembly procedures of the rocket vehicle.
DoD has indicated that it plans to review its internal
procedures for the approval of Woomera Prohibited Area activities
and that the MoU with SLASO may also be reviewed.
In addition to these safety actions, the Investigator issues the
following recommendations.
1) That Astrotech review the:
a) suitability of the Nike fins for use on the Terrier
vehicle;
b) suitability of the fin support attachment structure when other
than Terrier fins are used;
c) suitability and effectiveness of the opposing set-screw
arrangement for securing and setting the Nike fin incidence angle
to the Terrier fin support structure; and
d) suitability of the use of sandbags at the base of the launcher
pedestal, in lieu of the specified grouting.
2) That SLASO require all Australian launch operators to submit a
comprehensive risk hazard analysis for independent verification
prior to the issuing of a licence, permit or exemption
certificate.
3) That SLASO consider requiring launch operators to submit their
risk hazard analysis to stakeholders and participants, for review
and discussion.
4) That launch infrastructure providers make available sufficient
resources to enable the provision of appropriate recording
equipment with suitably trained personnel to provide additional
recorded evidence to aid any occurrence investigation that may be
necessary.
5) That overseas organisations involved in an Australian launch
provide any risk hazard analysis and/or assessment to SLASO to
better enable SLASO to properly assess a launch application.