Challenger's L-SRB Not "Tracking Orbiter" at End

Months before the release of the Rogers Report, two NASA officials
testified to the Rogers Commission concerning a pre-detachment
"rotation" of Challenger's right SRB, relative to the orbiter.

First, on February 13, 1986:

http://history.nasa.gov/rogersrep/v4part5a.htm#1

MR. LEE: ... At the same time period we see an unusual occurrence of
the right hand, what appears to be the right hand solid rocket
booster, the base, what appears to be at the base coming out, okay. So
like it is pivoting about the top, and it is in fact rotating
relative, at an angle relative to the rest of the stack. And we
compare that data with what is happening in the orbiter and the other
SRB.

MR. FEYNMAN: And you have gyros in each instrument that are different
from each other?

MR. LEE: That's right, and the way we would explain that would be that
base rotating out. In the same time period we get a lot of high rate
actuator commands between, say, a little after 72 seconds up to about
72 1/2 seconds, and those are not all tied together and explained. We
think we have come detached at the base, ...

Next, on March 7, 1986:

http://history.nasa.gov/rogersrep/v5part3b.htm#4

MR. MOSER: Then at a little greater than 72 seconds into the flight is
where we see motion of the right-hand solid rocket booster to the rest
of the launch vehicle, and that is shown on chart M-19, where here I
display the rotation of the pitch of the right-hand solid rocket
booster to that of the left-hand. Not shown on this data is the fact
that the left-hand solid rocket booster rate gyro is tracking exactly
with that of the orbiter, and that is the way all three of the
elements or all four elements - the orbiter, the external tank, and
the two SRB's - have been tracking up until this point. It is 72.201
seconds, we see a deviation from the right-hand solid rocket booster.
It is our indication that something has failed in the aft attachment
of the solid rocket booster to the external tank, ...

(Viewgraph M-19.) [Ref. 3/7-45]
http://history.nasa.gov/rogersrep/v5p1176a.htm

In Moser's above-referenced telemetry plot, the trace with a
terminally negative *yaw* rate is clearly labeled R-SRB, indicating
that Moser had used said R-SRB *yaw* rate for his assumption about
"the rotation of the pitch of the right-hand solid rocket booster to
that of the left-hand."

In Volume III of the Rogers Report (eventually released to the public
late that summer), the terminal SRB pitch rates appear as well:

http://history.nasa.gov/rogersrep/v3n48a.htm

Also with the release of that volume, terminal pitch and *yaw* rates
for the orbiter's ME #1 (apparently incorrectly re-labeled
"pitch/roll") finally became available to the public. (Main Engine #1
is centered with respect to the orbiter's fuselage.) You will find the
original "YAW" caption to the upper-left of the lower plot (as it was
with the relevant SRB plot):

http://history.nasa.gov/rogersrep/v3n49a.htm

I believe it is clear from the above-linked telemetry plot that this
key *orbiter* yaw rate is consistent with the terminal yaw rate of the
*right* SRB, rather than the left SRB as NASA claimed.

Conclusion: With respect to terminal orbiter telemetry to which we
later gained access in the Rogers Report, earlier testimony of
high-level NASA officials misrepresented ME gimbaling critical to a
fair determination of the disaster's cause.

John Maxson (see also www.mission51l.com/challenger.htm)