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Location: UFOUpDatesList.Com > 2007 > Mar > Mar 29

Re: An E-Mail To BadAstronomy On Apollo 11 UFO -

From: Lan Fleming <lfleming6.nul>
Date: Wed, 28 Mar 2007 12:52:58 -0500
Fwd Date: Thu, 29 Mar 2007 08:19:32 -0400
Subject: Re: An E-Mail To BadAstronomy On Apollo 11 UFO -


>From: James Smith <lunartravel.nul>
>To: ufoupdates.nul
>Date: Tue, 27 Mar 2007 12:02:53 -0400 (GMT-04:00)
>Subject: Re: An E-Mail To BadAstronomy On Apollo 11 UFO

>>From: Brad Sparks <RB47x.nul>
>>To: ufoupdates.nul
>>Date: Tue, 27 Mar 2007 05:26:29 EDT
>>Subject: Re: An E-Mail To BadAstronomy On Apollo 11 UFO

>>>From: James Smith <lunartravel.nul>
>>>To: ufoupdates.nul
>>>Date: Sun, 25 Mar 2007 11:37:06 -0400 (GMT-04:00)
>>>Subject: Re: An E-Mail To BadAstronomy On Apollo 11 UFO

>>>I have to agree with Lan about the coordinate system being Earth
>>>Centered Inertial and not body (CSM) centered as you seem to
>>>think it is. Thus the -X is not really retrograde.

>>The Apollo 11 Mission Report describes the effects of the
>>Separation (or Evasive) Maneuver on its arrival at the moon as
>>slowing the spacecraft arrival time by about 32 minutes, meaning
>>the burn was indeed _retrograde_. Velocity changes from
>>maneuvers in that report in Table 7-II Trajectory Parameters are
>>related to what is designated the "Space-fixed Velocity" changes
>>in the "body-centered, inertial reference coordinate system. "
>>(PDF p. 93). But when the report tabulates the maneuvers with X,
>>Y and Z components in Table 8.6-II Maneuver Summary a footnote
>>states that "Velocities are in earth- or moon-centered inertial
>>coordinates; velocity residuals are in body coordinates."

>Re-examining the Apollo 11 Mission report (Table 7-II) shows
>that you are right about the "retrograde" firing. It lists the
>space fixed velocity before and after firing. For the separation
>and midcourse maneuvers, there is a velocity reduction.  Live
>and learn! TLI and TEI have velocity increases as one would
>expect before and after firings. Also the LOI has a velocity


You're right, but I'm a little doubtful about the accuracy of
the velocities listed in that table because none of them are
above escape velocity:

    v-escape = (sqrt 2MG/R).

R is the distance from the Earth's center to the spacecraft, M
is Earth mass (5.98e24kg), and G is gravitational constant
(6.73e-11 in MKS units). The escape velocity at SIVB second cut-
off altitude should be 36,088  ft/sec, but the table lists a
final velocity of 35,567 ft/sec.  m/ft). Unless I'm mistaken,
the Apollo spacecraft was supposed to have reached escape
velocity. Plus, the polar coordinates of the delta-velocity
vector indicate a prograde direction relative to the moon's
position.

But regardless of whether the delta-v was retrograde or
prograde, taking gravitational differences into account makes
the distances between an SLA panel and the spacecraft larger
than they would be assuming they both have the same
acceleration. (I was wrong in the last message, the distance
would be 550 miles due to the midcourse correction, when the UFO
was sighted, not 900 because the time from the midcourse
correcction was 36 hours, not 48.) The distance is  much larger
if you take the first maneuver by itself into account because
more time elapsed and the gravitaty gradient much greater close
to Earth. I suspect that the S-IVB ended up 6000 miles away from
the spacecraft  due to a similarly small change in velocity,
maybe around around 20 ft/s, too. They only vented some
propellants to get whatever delta-V was needed; they didn't
have to fire the booster engines again.

The simulation is pretty easy to program, by the way. All you
have to do is select a small enough time step. DT, (like 1/10
second), and the on each iteration, add (MG*DT/R^2) to the
velocity, V, and then add DT*V to the distance, R.  You can see
the effect a small initial velocity difference makes by running
the simulation twice. I used a delta-V of 6 meters/second. This
is a "brute force" simulation. There are far more sophisticated
methods NASA used to compute trajectories, and in 3 dimensions
rather than one, of course.

>The minimum jettison angle with respect to the S-IVB axis was
>supposed to be 90 degrees, thus no forward velocity component at
>release.  Only these telescopic SLA images can help here.

The panel jettison angle and speed no longer seem very
important, since the the speeds of the spacecraft maneuvers are
considerably larger.



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