NASA's rebuttal to speculation about Challenger transcripts

From: bwelch@hqops.hq.nasa.gov (BWelch)
Newsgroups: sci.space.shuttle
Subject: Challenger transcript history
Date: Mon, 29 Jan 1996 17:11:05 -0400
Organization: NASA Headquarters, Code Z

I am posting this message in response to the continued interest in the
Challenger transcripts, and in the hopes that a detailed listing of events
will help quell a persistent myth.  There are no "partial" Challenger
transcripts, and there are no voice tapes recorded after the breakup of
the vehicle.  Even ten years after the accident, this continues to be the
source of myth and speculation. It probably will continue to be for some
years to come.  I hesitate to even revisit the topic, but the continued
misinformation, including completely false stories appearing on many
"news" radio stations around the country in recent months, suggest that
perhaps a detailed accounting of what did and did not happen will at least
arm some responsible souls out there with the real data.  I hope some of
you will save the following and pass it on in the weeks, months and years
to come when someone on the 'net asks about it:

The Challenger onboard intercom was recorded on one of two operational
recorders (hereafter, "ops" recorders) aboard the orbiter. 

Shuttle orbiters have several onboard components with memory-saving
capacity:  the General Purpose Computers (GPC), Ops recorders, a payload
recorder, and a Modular Auxiliary Data System (MADS) recorder.  Personal
cassette recorders are available to crews for note taking, but it is
thought that they were not in use during Challenger's launch.

The ops recorders store Shuttle ascent telemetry data and air-ground voice
channels.  Ops recorder 1 records the 60 kilobits/second (KBPS) data
stream from the three main engines; Ops recorder 2 records at 128 KBPS the
Shuttle downlink/downlist data and the two air-ground channels.  Circa
1986, the Ops recorders were played back after reaching orbit to bridge
gaps in real-time telemetry to ground stations or through Tracking and
Data Relay Satellite coverage.

On March 19, 1986, NASA announced that four of five Challenger General
Purpose Computers (GPC) had been recovered from the Atlantic and moved to
the IBM Federal Systems Division facility in Owego, NY.  The GPCs were
cleaned under controlled conditions and submerged in deionized water at
Kennedy Space Center prior to air shipment March 16, 1986, to Owego.  The
GPC ferrite core memories were examined for any possible residual data --
a process that at the time was expected to take several months.  This
information was in the form of data--not onboard voice--and this path was
pursued to add any possible additional information to the accident
investigation.  Many weeks later, it was found that the additional data
frames did not measurably add to the information already gathered during
the investigation.

Both Ops recorders and the MADS recorder were recovered and were taken to
the Marshall Space Flight Center, Huntsville, AL, for cleaning in clear,
cold water and for subsequent drying in a thermal vacuum chamber.  The
cleaning/drying of recorder tapes took about two weeks, after which the
tapes were taken to the Johnson Space Center for extraction of any usable
data.  

On April 30, 1986, JSC announced that it had so far been unable to extract
data from the tapes.  "Because the long exposure to salt water has
deteriorated the tapes such that they cannot be unwound from the reels
without total loss of the data, all attempts to date to recover
information from then have been unsuccessful."  JSC also reported that one
of the personal cassette recorders available to crew members for
note-taking had been recovered, but it was still in its stowage container,
indicating it had not been used, and the recording tape was too severely
damaged to be played back.

On July 16, 1986, JSC announced that additional efforts had been made to
salvage the tapes from the Ops recorders.  The tapes underwent treatment
at IBM's facility in Tucson, Arizona, to remove magnesium oxide caused by
seawater reaction with magnesium tape reels.  The tapes were first treated
with diluted nitric acid, and then rinsed in methanol.  Earlier treatment
immediately after recovery had included submersion in clear, chilled water
until methods for salvaging the tape could be devised.

Through these types of intensive efforts, it ultimately was possible to
listen to the tapes and provide a transcript of them to the media.  The
transcript was made available on July 28, 1986 at 4:30 p.m. EDT. 
Initially, NASA had concluded that the crew was unaware of the events
preceeding the breakup of the Challenger.  But detailed analysis revealed
a final comment, providing "the first potential indication of awareness on
their part at the moment when all data was lost at 73 seconds into the
flight," NASA announced.  That comment was "Uh oh," attributed to Pilot
Michael Smith.

There is no transcript after the 73-second point because once the
Challenger began to break up, power was lost and the recorders stopped
running.  

Out of respect for the families of the crew, NASA felt strongly that the
voice tape audio should not be released.  A transcript was released and
the contents were widely reported for several days.  Later, the New York
Times sued NASA for release of the tape audio itself, a case which
ultimately went to the Supreme Court, with the court ruling in NASA's
favor.

In the July 28 news release announcing the transcript and the release of a
report from astronaut Dr. Joseph Kerwin on the cause of death of the crew
members, Rear Admiral Richard Truly, then head of NASA's Office of Space
Flight, thanked all of the people involved in the massive salvage effort. 
"Their work deserves the admiration and thanks of the American people, and
I believe their efforts have now closed this chapter of the Challenger
loss," he said.  "We have now turned our full efforts to the future, but
we will never forget our seven friends who gave their lives to America's
space frontier."

Brian Welch
Chief, News & Information
NASA Headquarters
Washington, DC