The Apollo 13 CSLM

The Apollo 13 Command-Service-Lunar Module on its Fateful Lunar Flight

This black and white photograph was taken with a Kodak 103a-D spectroscopic 4x5 glass plate at the f/16
cassegrain focus of the 24-inch reflecting telescope using a special 4x5 camera. This picture was made from
0523 to 0528 UT on April 12, 1970 (5 minute exposure). This photograph was taken nearly 2 days before
the explosion of one of the on-board fuel cells that created the world-wide intense interest and concern for
these three brave men, and of course, the now famous and quite accurate Apollo 13 movie.

A unique view of the Apollo 13 CSLM: the center dot is the Apollo 13 Command/Service/Lunar Module
(CSLM) as seen Table Mountain through the 24-inch telescope. The four dots around the CSLM are the
tumbling SLA panels. The diagonal jagged white lines crossing the picture from the lower left to the upper
right are star trails during the 5 minute exposure. The actual exposure was taken by guiding on the distant
S-IVB upper last stage spent rocket body of the Saturn V launch vehicle. This was very difficult, since the
brightness of the S-IVB was extremely faint in the 1200x magnification guide eyepiece, thus the jagged star
trailed images.

The CSLM was a steady faint dot of magnitude 13. The SLA panels are ejected from the top of the S-IVB
when the CSM detached itself from the S-IVB. The CSLM turned 180 degrees around, and then docked
with the LM (Lunar Module). The CSM, attached to the LM, then becomes the CSLM. The 4 SLA panels,
blown clear of the top of the S-IVB for the CSM to access the LM are tumbling and, thus, appear to be
flashing at irregular times. The flashes sometimes appeared as bright as magniture 9, but flashes of sunlight
onto these tumbling panels were few and far between...the reason they actually appear fainter than the CSLM
on this picture.

To see a diagram of the upper or last stage, called the S-IVB, click here. In this illustration, you can see how
the CSM (on the top) has to turn 180 degrees around, once in earth orbit, then the 4 SLA panels are blown
away, and the CSM docks with the LM. The entire package then becomes the CSLM. The 4 SLA panels
are not marked in the illustration, but are the metal protection covers placed between the CSM and the top
of the S-IVB to encapsulate the LM.

During the Apollo program, I observed all of the lunar missions with the exception of Apollo 17, the last one,
because of clouds at the observatory. At first, no one was sure what we were seeing while observing these
lunar missions. Many with small telescopes were reporting seeing the CSLM, when in fact they were really
seeing the flashing SLA panels. As the distance increased from the earth, each Apollo CSLM appeared much
further from these flashing SLA panels, so that many people, unfortunately, never saw the spacecraft itself.
Furthermore, the S-IVB was brighter that the CSLM because of its size, and many others saw this instead of
the CSLM. We observed the S-IVB and CSLM of Apollo 8 when it was nearly 200,000 miles from the earth,
but they were extremely faint, and with no sign of the SLA panels.

The crew members of Apollo 13 were James A. Lovell, Jr., John L. Swigert, Jr. and Fred W. Haise, Jr.

Click here for the full Apollo 13 mission history: Apollo 13 Web Page

Table Mountain Observatory, operated by the Jet Propulsion Laboratory (JPL), is located just west of the
town of Wrightwood, California at an elevation of 7500 feet.

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