In reading this report I am reminded of readings from Pioneer 10. At 16
bits per second, a 192 bit frame of data took 12 seconds to collect and a
number of frames were required to map a whole Master Frame because a given
bit position might be used for different jobs in different frames and you
needed to know what frame you were looking at to know what that data bit
stood for, so both the frame number, where it was in the frame, and the data
value determined what you were looking at. If your frame number was
missing or wrong, then the data value you were looking at may have no
meaning for you. - LRK -
---CBS report below
Guidance and navigation data show the shuttle was in an
"uncommanded" orientation, yawing rapidly to one side, presumably
toward Earth, in what may have been the start of a banking tumble.
The yaw rate - a measure of how fast Columbia's nose was swinging to
one side - was at least 20 degrees per second, the maximum value the
sensors are designed to measure. The actual yaw rate may have been
higher.
---
You make decisions on how to parse the telemetry stream and what range of
values you expect to cover. Temperatures normally don't change rapidly so
you can send samples interspersed with other values like battery voltages,
bus voltages, currents and the like. You want to save space and time for
your scientific instruments and data. You may change the formats from
Science with a little health or turn it around and be sending a lot of
health data and a little science. Data transmission rates are designed to
take into account how far away you are and what conditions you are operating
under. I don't have any information about what the Shuttle was using but
some of the following may give you an idea of what the recovery crew may be
up against. - LRK -
You often send analog values mapped to a digital value that fits with your
telemetry processing and then on the ground you apply a polynomial to the
digital value to get back your analog data. Y = (C + x*C1 + xsq*C2 +
xcube*C2 .....) or y = (C + X(C1 + X(C2 + X(C3 + XC4)))) so when you send a
data 0 you are at the lowest you expected to be measuring and you see the
base offset value of C. On Pioneer 10 there were a number of temperature
values that were lower than they ever expected to go and so you saw a steady
value of "C" each time that value was sent. You have to decide how large a
value you are going to use for "X". If you chop up your value using the
numbers from 0 to 63, you get to slice up your expected range of data into
64 pieces. That determines how much your reconstitueted analog value changes
for a change of one step in your data value. - LRK -
There are a lot of Yes-No type of values that you can use 1's and 0's to
represent the states with and further you might pack them say into an eight
bit word (sometimes 7 bit or 3 bit on older spacecraft). If you corrupt one
of these packed bytes you might have trouble interpreting the data for a
number of operations. - LRK -
---CBS report below
It is also possible both scenarios are false. Data from this final
two-second period was corrupted by transmission errors and as such,
it is subject to error or misinterpretation.
---
On Lunar Prospector, some 16 bit numbers were pre-processed to 8 bit bytes
on the spacecraft and transmitted. On the ground you applied a special
processing program to bring this compressed value back to a statistically
close representation of the original 16 bit value. Data compression is
important to you folks when you gather image data from a digital camera and
then have it saved as a JPEG on your solid state memory stick for transfer
to your computer. Your image reading program then de-compresses that data
and displays your image. How well you see the displayed image is further
affected by what your display device is capable of. What is it that is
said, "Beauty is in the Eye of the Beholder." - LRK -
So read the report and lets hope that they find the 1's and 0's in their
proper place and then interpret them accurately. We will watch and see what
truth is reported. - LRK -
Larry
==========================================================
CBS News Coverage of Shuttle Mission STS-107
Prepared by William Harwood, CBS News/Kennedy Space Center
This status report is available online at the CBS News
Space Place at:
http://www.cbsnews.com/htdocs/space_place/framesource_current.html
===================================================================
STS-107 STATUS REPORT 85
Last Updated: 06:00 p.m., 03/09/03 (all times Eastern)
Changes and additions:
SR-83: Plume may have entered wheel well from within wing, exited
through landing gear door frame; other scenarios remain possible
SR-84: NASA focuses on 10 shuttle failure scenarios; Stone to
replace Ham in NASA probe
SR-85: Updated NASA timeline provides insight into shuttle's final
seconds
===================================================================
CBS NEWS STATUS REPORT
6:00 p.m., 03/09/03, Update: Updated telemetry timeline shows
shuttle on autopilot through last data transmission; hand controller
may have been briefly engaged.
Ongoing analysis of the final two seconds of telemetry from the
shuttle Columbia during re-entry Feb. 1 shows the doomed ship's
fuselage, crew module, right wing and right-side rocket pod were
essentially intact 32 seconds after the commander's final
transmission and that the orbiter's digital autopilot was still
flying the spacecraft when data finally stopped flowing. A computer
alarm generated in that final two seconds of data suggests one of the
pilots' joystick hand controllers may have been briefly engaged, but
the autopilot was never deactivated before contact was lost.
By that point, however, there was nothing the crew could have done
to stop the quickening disaster. The telemetry shows Columbia's left
wing and left-side orbital maneuvering system rocket pod were either
gone or severely damaged, the ship's hydraulic system was empty, its
flash evaporator cooling system was in shut down and multiple
computer alarms were being generated because of lost data from the
orbiter's left side orbital maneuvering system rocket pod.
Guidance and navigation data show the shuttle was in an
"uncommanded" orientation, yawing rapidly to one side, presumably
toward Earth, in what may have been the start of a banking tumble.
The yaw rate - a measure of how fast Columbia's nose was swinging to
one side - was at least 20 degrees per second, the maximum value the
sensors are designed to measure. The actual yaw rate may have been
higher.
That same two seconds of "ratty" telemetry shows one of the
cockpit's two rotational hand controllers, or joysticks, may have
been briefly engaged as early as 9:00:01.7 a.m. That was nearly 30
seconds after commander Rick Husband's final interrupted transmission
to Houston at 8:59:32 a.m. But the timing is uncertain because of the
duration of software-driven data sampling rates. The final bit of
telemetry, however, shows Columbia digital autopilot was still in
control when the flow of data finally ceased and that the hand
controller was in its normal "centered" position. As such, it is not
known whether the RHC was bumped inadvertently by the commander or
pilot or whether one of them intentionally gripped the stick with
thoughts of taking over manual control.
It is also possible both scenarios are false. Data from this final
two-second period was corrupted by transmission errors and as such,
it is subject to error or misinterpretation. But it was included as
part of revision 14 to NASA's STS-107 Mishap Investigation Master
Timeline, a revision that was never released, sources say, because an
updated version is in the final stages of preparation. At least some
of the data in revision 14, which was obtained by CBS News late last
week, may have been corrected, eliminated or expanded in the latest
revision. This status report will be updated as warranted when the
new revision is released.
In any case, engineers now believe the main body of the spacecraft
did not begin breaking up until nearly 20 seconds after the final
two-second burst of telemetry. Vehicle breakup was preceded by the
separation of at least three major pieces of debris beginning around
9:00:02 a.m., at almost the same instant the final two seconds of
telemetry began flowing back to Earth after a 25-second data dropout.
The timeline also includes more than a dozen "debris shedding"
events recorded by observers on the ground as Columbia crossed above
California and the southwestern United States. The first such
confirmed instance of debris falling away from the shuttle occurred
around 8:53:44 a.m., 18 seconds after the spacecraft passed above the
California coast just north of San Francisco.
But it is the orbiter's final minutes that grip the imagination as
the data plays out with a sort of slow-motion inevitability.
At 8:59:32 a.m., Husband called Houston, presumably to report or
confirm a computer fault message showing lost pressure from both
left-side main landing gear tires.
"Roger, uh, buh..." he radioed, but he was cut off. The "buh" may
have been the beginning of the word "both" or possibly "before."
There is no way to know, but engineers now say that final
transmission was interrupted not because of the mounting problems on
board the shuttle, but because the line of sight between a forward
antenna cluster and the NASA communications satellite then in use was
blocked by Columbia's vertical stabilizer and aft engine compartment.
In any case, raw data continued to flow for another five seconds
before it, too, was interrupted by antenna blockage. A master alarm
sounded in the cockpit during those five seconds, computer messages
were generated that noted problems with the shuttle's flight control
system and an electrical system powered down.
Toward the end of that five seconds, the aerodynamic "sideslip"
being experienced by Columbia began reinforcing the aerodynamic drag
already pulling the ship to the left because of problems with the
left wing. At 8:59:36 a.m., the digital autopilot, struggling to keep
the shuttle properly oriented, was forced to drop the left wing to
compensate for the increasing aerodynamic forces acting on the craft.
Less than a second later, the autopilot commanded a right-pointing
yaw thruster on the aft right side of the shuttle to fire to help
counteract the growing yaw motion. Two other jets already were firing
and a fourth was commanded on less than a second after the third.
And then, at 8:59:37.396 a.m., telemetry was cut off. For the next
25 seconds, no telemetry was received due to antenna blockage. A
final two-second burst came down beginning at 9:00:02.660 a.m. The
data were garbled and some of the readings are not clear cut. But
engineers were able to recover computer message stored in "buffers"
that provide at least some insight into what was going on during that
preceding 25 seconds.
The shuttle's primary flight computers generated a "roll
reference" fault message around 8:59:46 a.m. Six seconds later the
first in a series of left OMS rocket pod alarms was generated by the
shuttle's flight computers. In the final two seconds of telemetry,
additional OMS pod alarms were generated, along with an alarm
indicating an apparent short circut.
In the final two seconds of telemetry, it appears Columbia's
hydraulic power units were operating relatively normally, the
shuttle's water spray boilers were cooling the hydraulic system
lubrication oil, the main propulsion system and aft engine
compartment were intact and the shuttle's three electricity
generating fuel cells were operating.
In addition, Columbia's communications equipment and navigation
systems were still functioning and temperature readings were still
being received from the ship's vertical stabilizer, body flap, main
engine compartment and the right wing.
But all three hydraulic systems were operating at zero pressure
with empty hydraulic fluid reservoirs, presumably because of severe
left wing damage that ruptured the triply redundant hydraulic lines.
Temperature readings from the left wing elevon actuators were absent,
the shuttle's flash evaporator cooling system had apparently shut
down and the majority of the sensors in the left orbital maneuvering
system rocket pod were either disabled or showing abnormal readings.
Major electrical problems were beginning to develop and elevated
temperatures were noted on the belly of the shuttle and along its
left side.
Guidance and navigation data suggests vehicle was in an
uncommanded attitude and was exhibiting "uncontrolled rates," the
timeline states. "Yaw rate was at the sensor maximum of 20 degrees
per second. The flight control mode was in AUTO. Based on the nominal
and off-nominal system performance described above, it appears that
the fwd/mid/aft fuselage, right wing and right pod were still intact."
The final bit of telemetry from Columbia showed a computer fault
message regarding the rotational hand controller. While the "digital
autopilot roll stick function" was initialized, "available vehicle
data indicates the RHC was in detent (in the normal centered
position) and (the) digital autopilot was in AUTO."
The CBS News STS-107 integrated timeline, currently in revision F,
includes telemetry data from revision 13 of NASA's master timeline.
The CBS timeline will be updated when the next official telemetry
update is released by the Columbia Accident Investigation Board.
Revision 14 of NASA's master timeline, discussed in general terms
above, has not been integrated into the CBS timeline at this point
because of the pending update.
==========================================================
WHAT THE MIND CAN CONCEIVE, AND BELIEVE, IT WILL ACHIEVE - LRK
==========================================================
http://www.LarryRussellKellogg.net
http://www.KelloggSerialReports.net/
Larry Kellogg's Radio Weblog
http://radio.weblogs.com/0119030/
