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December 1,
2020
The
instrument platform of
the 305-meter
telescope at Arecibo
Observatory in Puerto
Rico fell at
approximately 7:55
a.m. Atlantic Standard
Time Dec. 1, resulting
in damage to the dish
and surrounding
facilities.
No
injuries were reported
as a result of the
collapse. The U.S.
National Science
Foundation ordered the
area around the
telescope to be
cleared of
unauthorized personnel
since the failure of a
cable Nov. 6. Local
authorities will keep
the area cordoned off
as engineers work to
assess the stability
of the observatory’s
other structures.
Top
priorities are
maintaining safety at
the site, conducting a
complete damage
assessment as quickly
as possible, and
taking action to
contain and mitigate
any environmental
damage caused by the
structure or its
materials. While the
telescope was a key
part of the facility,
the observatory has
other scientific and
educational
infrastructure that
NSF will work with
stakeholders to bring
back online.
“We are
saddened by this
situation but thankful
that no one was hurt,”
said NSF Director
Sethuraman
Panchanathan. “When
engineers advised NSF
that the structure was
unstable and presented
a danger to work teams
and Arecibo staff, we
took their warnings
seriously and
continued to emphasize
the importance of
safety for everyone
involved. Our focus is
now on assessing the
damage, finding ways
to restore operations
at other parts of the
observatory, and
working to continue
supporting the
scientific community,
and the people of
Puerto Rico.”
The
investigation into the
platform’s fall is
ongoing. Initial
findings indicate that
the top section of all
three of the 305-meter
telescope’s support
towers broke off. As
the 900-ton instrument
platform fell, the
telescope’s support
cables also dropped.
Preliminary
assessments indicate
the observatory’s
learning center
sustained significant
damage from falling
cables.
Engineers
arrived on-site today.
Working with the
University of Central
Florida, which manages
the observatory, NSF
expects to have
environmental
assessment workers
on-site as early as
tomorrow. Workers at
the observatory will
take appropriate
safety precautions as
a full assessment of
the site’s safety is
underway.
NSF
intends to continue to
authorize UCF to pay
Arecibo staff and take
actions to continue
research work at the
observatory, such as
repairing the 12-meter
telescope used for
radio astronomy
research and the roof
of the LIDAR facility,
a valuable geospace
research tool. These
repairs were funded
through supplemental
congressional
appropriations aimed
at addressing damage
from Hurricane Maria.
Once
safety on site is
established, other
work at the
observatory will be
carried out as
conditions permit.
NSF
will continue to
release details as
they are confirmed.
Additional
information,
including engineers’
assessments of the
structure, can be
found in NSF’s Nov. 19 news release.
Background
Although
the platform’s fall
was unplanned, NSF,
UCF and other
stakeholders,
including engineering
firms contracted by
UCF, had been
monitoring
developments at the
305-meter telescope
that indicated an
increased risk of a
collapse.
In
August, one of the
305-meter telescope’s
cables unexpectedly
detached. The
remaining cables were
expected to bear the
load without issue as
engineers worked on
plans to address the
damage. However, a
second cable broke
Nov. 6. Engineers
subsequently found the
second snapped at
about 60% of what
should have been its
minimum breaking
strength, indicating
that other cables may
be weaker than
expected, and advised
that the structure
could not be safely
repaired.
Both
cables were attached
to the same support
tower. If the tower
lost another cable,
the engineer of record
noted, an unexpected
collapse would be the
likely result. Since
NSF’s Nov. 19 announcement that it would plan for
decommissioning of
the 305-meter
telescope,
surveillance drones
found additional
exterior wire breaks
on two cables attached
to the same tower. One
showed between 11-14
broken exterior wires
as of Nov. 30 while
another showed about
eight. Each cable is
made up of
approximately 160
wires.
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Arecibo
Observatory’s
305-meter telescope
suffers collapse 
