Part 2 (M)
Recovery, Spacecraft Redefinition, and First Manned Apollo Flight
June through July 1968
ASPO Manager George Low advised Apollo program officials at KSC that, to
collect adequate data for evaluating any potential toxicological hazard
inside the spacecraft, collection of gas samples of the cabin atmosphere
must be made for 12 hours during the unmanned altitude chamber test with
all systems operating. Low asked that this requirement be included in
the spacecraft test procedures. (Purpose of a total CSM 101 and LM-3
toxicological evaluation was to verify that no toxic contaminants were
given off by the nonmetallic materials used in the crew compartments.)
Ltr., Low to R. O. Middleton, KSC, "Toxicological evaluation of
CSM 101 and LM-3," June 3, 1968.
Apollo Program Director Sam Phillips asked ASPO Manager George Low to
investigate the value of using freon as a fire extinguishing agent
inside the spacecraft. Admittedly, Phillips said, MSC had considered
using a freon extinguisher system shortly after the AS-204 accident, but
it had been rejected, largely because of toxicity factors and because
tests had shown the agent ineffective in extinguishing combustion of
polyurethane in a pure oxygen atmosphere. A number of factors now
dictated a reevaluation of such an extinguisher system, however:
In view of these changes, Phillips said, a freon extinguishing system
might be better than the present jelled water extinguisher (quicker
activation and reduced equipment damage). He asked that Low not overlook
this potential improvement in crew safety, which could be of particular
value during the high-risk period of launch, when the crew was
essentially immobilized by the forces of acceleration.
- Additional testing of late had indicated a lower toxicity problem
than earlier believed.
- The addition of oxygen masks to the spacecraft now afforded some
protection against a toxic atmosphere.
- Because of post-accident changes inside the cabin, the flammability
problem had been reduced to a few specific materials (quite different
from polyurethane foam) sited in compartmentalized locations inside the
- The oxygen-nitrogen mixed gas had been selected as the prelaunch
atmosphere inside the cabin.
Ltr., Phillips to Low, "CBrF3 (Freon 1301) as a Fire Extinguishing
Agent," June 3, 1968.
George E. Mueller, Associate Administrator for Manned Space Flight,
wrote MSC Director Robert R. Gilruth to express his personal interest in
lunar extravehicular activity (EVA) training for the Apollo crews of the
F and G missions (i.e., the initial lunar landing and subsequent
flights). Because of the complexity of the EVA tasks that the astronauts
must perform, Mueller said, crews for those missions should be selected
as early as possible. Also, realistic training - including a realistic
run-through of many of the lunar surface tasks, especially development
of the S-band antenna and the Apollo Lunar Surface Experiments Package
and sampling operations - must be conducted to ensure that the crews
competently carried out the various scientific experiments and other
tasks during their brief stays on the moon.
Ltr., Mueller to Gilruth, June 5, 1968.
ASPO Manager George M. Low and others from MSC met with Grumman's LM
engineering staff, headed by Thomas J. Kelly, to discuss the descent
stage heatshield and thermal blanket problems associated with reduced
thrust decay of the descent engine at lunar touchdown. Several
significant decisions were reached:
Memo, Low to C. H. Bolender, "LM descent stage base
heatshield," June 8, 1968.
- The touchdown probe was lengthened to 1.6 meters.
- Effective on LM-5 and later vehicles, Grumman would "beef
up" (both structurally and thermally) the base heatshield.
- Grumman was to conduct a series of tests on overpressure of the
- Grumman would begin design studies of a jettisonable descent engine
- Landing stability would be reexamined with the existing thrust
tailoff profile (a study to be made either by Grumman or by Boeing; Low
asked Maxime A. Faget, Director of Engineering and Development at MSC,
to review this proposed test plan and to recommend where it should be
conducted, for best cost, schedule, and technical capabilities).
In his weekly progress report to the NASA Administrator, Deputy
Administrator for Manned Space Flight George E. Mueller cited several
important Apollo events during the first week of June:
Memo, Mueller to NASA Administrator, "Manned Space Flight Weekly
Report - June 7, 1968," June 10, 1968.
- On June 1, technicians at MSC completed thermal-vacuum testing on
LTA-8 to support LM-3, including 45% hours of manned testing. All
spacecraft systems functioned normally, and preliminary results
indicated that all significant test objectives had been realized.
- Engineers and technicians at KSC completed receiving inspection of
CSM 101 on June 3. That inspection revealed fewer discrepancies than had
been present on any other spacecraft delivered to the Cape. Pre-mate
inspection of CM 101 also was completed, as were leakage and functional
tests on the electrical power and reaction control systems. SM 101 was
in the altitude chamber being prepared for combined systems testing.
ASPO Manager George M. Low met with Christopher C. Kraft, Jr., and
Donald K. Slayton, Directors of MSC Flight and Flight Crew Operations,
and several members of their staffs (including astronaut Walter M.
Schirra, Jr.) to discuss using the flight combustion stability monitor
(FCSM) on the Apollo 7 flight. (The FCSM was a safety device to shut
down the service propulsion system [SPS] automatically in the event of
rough combustion or instability.) At the insistence of the Propulsion
and Power Division, they agreed to use the FCSM for all SPS burns on
Apollo 7. On all "noncritical" burns, two attempts to start
the engine would be made with the FCSM active. Should the stability
monitor shut down the engine on both those attempts, a detailed review
of the situation would be made before again attempting to start the
engine. On "critical" burns (i.e., the abort-to-orbit and
reentry burns), should the FCSM halt the burn the SPS engine would be
restarted immediately with the FCSM inactive on the assumption that the
shutdown was caused either by an FCSM malfunction or by an engine
instability that would not reoccur on the next start.
Low, Kraft, and the others unanimously wanted to eliminate the FCSM
before a lunar mission, because on this mission lunar orbit and
transearth insertion burns were highly critical and inadvertent
shutdowns would cause major trajectory perturbations. Representatives
from the Propulsion and Power Division (PPD) contended that, because of
the relatively small number of bomb tests carried out on the Block II
SPS engine, flight-testing of the engine before the lunar mission would
be inadequate to demonstrate engine stability under all conditions. Low
therefore asked Engineering and Development Director Maxime A. Faget and
PPD Chief Joseph G. Thibodaux, Jr., to plan a ground test program that
would give sufficient confidence in the SPS engine to eliminate the FCSM
before undertaking lunar missions.
Ltr., Low to Thibodaux, "Use of FCSM on Apollo 7," June 11,
Dale D. Myers, Apollo CSM Program Manager at North American Rockwell,
advised MSC officials of his company's investigation of two pilot-chute
riser failures during recent drop tests of the Block II earth-landing
system. Should there be any imperfections in either hardware or
assembly techniques, Myers explained, the Block II pilot chute and
riser system could be a marginal-strength item. Investigations had
determined that early manufacturing processes had allowed a
differential length between the two plies of nylon webbing in the
pilot-chute riser which caused unequal load distribution between the
two plies and low total riser strength. Because of the earlier test
failures, Myers said, the pilot chute riser had been redesigned. The
two-ply nylon webbing had been replaced by continuous suspension lines
(i.e., 12 nylon cords) and the 5.5-millimeter-diameter cable was
changed to 6.3-millimeter cable. He then cited a series of recent tests
that verified the redesigned pilot-chute riser's strength to meet
deployment under worst-case operational conditions.
Ltr., Myers to K. S. Kleinknecht, MSC, June 11, 1968.
Apollo Program Director Phillips wrote MSC Director Gilruth concerning
the April 10 proposal for a two-burn lunar orbit insertion (LOI)
maneuver and a spring ejection of the LM from the spacecraft-lunar
module adapter. Phillips agreed to the two-burn LOI in place of the
originally planned one burn if results of an analysis should prove the
requirement. He specified that an analysis be made of the tradeoffs and
that the analysis include the risk of crash, the assumed risks due to
lengthening the lunar orbit time (about four hours), and risks due to an
additional spacecraft propulsion system burn, as well as the effect of
the lunar gravitational potential on the ability to target the LOI
maneuver to achieve the desired vector at the time of LM descent. The
proposal for spring ejection of the LM from the SLA was approved with
the provision that a failure analysis be made in order to understand the
risks in the change.
Ltr., Samuel C. Phillips, OMSF, to Robert R. Gilruth, MSC, June 17,
NASA and contractor technicians successfully conducted the final
parachute drop test to qualify the Apollo CSM earth-landing system. The
Block II ELS thus was considered ready for manned flight after 12 Block
I, 4 Block II, and 7 increased-capability Block II Qualification Tests -
that had followed 77 Block I, 6 Block II, and 25 increased-capability
Block II Development Drop Tests.
Memo, George E. Mueller, NASA OMSF, to NASA Administrator and Deputy
Administrator. "Manned Space Flight Weekly Report - July 5,
1968," July 8, 1968; NASA Technical Note (NASA TN D-7437),
"Apollo Experience Report-Earth Landing System."
ASPO Manager George M. Low asked Aaron Cohen, one of his chief
technical assistants, to investigate the ability of the Apollo
spacecraft to withstand bending loads imposed by a failure of one or
more engines on the Saturn V launch vehicle (as well as actual loads
that would be imposed on the spacecraft). During the previous week, Low
and the Configuration Control Board had ruled out making any
significant design changes to cope with a Saturn V engine failure.
Specifically, Low asked how bending loads on the spacecraft were
derived; what bending loads were imposed on the spacecraft during the
Apollo 6 mission, where two J-2 engines were cut off
during the flight; what was the probability - and criticality - of an
S-IC engine's failing and thereby imposing high bending loads; and
whether abort limits should be established for an engine failure.
Memo, Low to Cohen, "Saturn V single engine out problems,"
July 5, 1968.
The Apollo Design Certification Review (DCR) Board met in Houston to
examine CSM 101 and the Block II CSM for proof of design and development
maturity and to certify the designs for flightworthiness and manned
flight safety. (Three earlier reviews directly supported this
penultimate scrutiny of the vehicle's development: the CSM 101 Design
Certification Review March 6-7, the Block II environmental control
system and spacesuit DCR May 8, and the DCR covering the CM land and
water impact test program June 6.) The board concluded that design
certification on CSM 101 was complete. Action and open items were
subsequently forwarded to the Centers for resolution, to be closed
before the Apollo 7 Flight Readiness Review.
Ltr., Samuel C. Phillips, NASA Hq., to distr., "CSM 101 and Block
II CSM Delta Design Certification Review," Aug. 28, 1968.
ASPO Manager Low informed Apollo Program Director Phillips of several
changes in the LM vibration testing program. Before beginning the
series of tests, he told Phillips, red line values were established on
critical components that were not to be exceeded. However, because of
the most recent test effort on LM-2, which resulted from the pogo
problem experienced during the flight of Apollo 6, Low was
forced to authorize vibration testing beyond the red line values
initially set for the spacecraft. This action, in turn, forced an
inspection and possible refurbishment of LM-2 to make it available for
an unmanned flight, should such a second unmanned LM test mission be
required. He then cited MSC's future plans for LM-2:
Phillips approved Low's action immediately. He urged Low to
"continue to give priority to that work which is necessary for
full and early resolution of the POGO and spacecraft structural
- For the planned drop tests with the vehicle, the upper decks would
be inspected and repaired or replaced where necessary.
- Should a LM-2 flight become necessary, all of the descent stage
upper decks would probably be replaced.
Ltr., George M. Low to Samuel C. Phillips, July 11, 1968, with
handwritten notation by Phillips dated July 11, 1968.
ASPO Manager George M. Low wrote to Grumman President Llewellyn J.
Evans to call his attention to the problem of continued propellant
leaks in the LM. "In spite of all of our efforts, last
summer" (i.e., with the extensive plumbing rework done on LM-1
after its delivery to Florida), Low said, technicians at KSC found a
leak on one of the lines on LM-3, even though no leaks had been
observed during checkout at Bethpage. Investigating the problem, Low
had learned that Grumman had made some propellant-system design changes
that had led to installation of four-bolt flanges with single teflon
O-ring seals - despite the fact that during the preceding summer NASA
and Grumman had jointly agreed not to use this joint on the LM vehicle.
This most recent problem, said Low, again points up the importance of
strictest control of all design changes in the spacecraft. Because of
the need for maintaining a lunar-configured LM as a design baseline,
all spacecraft design changes had to be carried through the Apollo
Configuration Control Board before implementation.
Ltr., Low to Evans, July 13, 1968.
NASA Apollo Program Director Samuel C. Phillips laid down Headquarters
and MSC interfaces with the Atomic Energy Commission (AEC) regarding the
SNAP-27 radioisotope thermoelectric generator for the Apollo Lunar
Surface Experiments Package (ALSEP). The Lunar Surface Program Office at
MSC was the field project office responsible for developing the ALSEP
system, and the radioisotope generator - as part of the ALSEP - had been
assigned to that office for system integration. Thus, the Lunar Surface
Program Office served as the AEC's primary contact on the SNAP-27 both
for ALSEP program matters and for data pertaining to flight safety and
documentation for flight approval. Phillips stressed that all data be
fully coordinated with Headquarters before being submitted to the AEC.
(Approval for the flight of any nuclear device rested ultimately with
the President, but formal documentation had to be concurred in by the
NASA Administrator, the AEC Commissioners, the Secretary of Defense, and
the National Aeronautics and Space Council.)
Memo, Phillips to George M. Low, ASPO, MSC, "Atomic Energy
Commission Interfaces," July 15, 1968.
NASA Associate Administrator George E. Mueller, Apollo Program Director
Samuel C. Phillips, and other high-ranking manned space flight officials
from Headquarters visited Bethpage for an overall review of the LM
program. Greatest emphasis during their review was on schedules,
technical problems, and qualification of the spacecraft's principal
subsystems. Mueller and Phillips cited several areas that most concerned
Mueller also suggested that Grumman consider eliminating the LM
rendezvous radar to save weight aboard the vehicle. He stated that VHF
ranging would be more accurate and would probably be the preferred mode
- Delivery schedules from subcontractors and vendors had slipped
significantly during the past year, to the point where many components
were only marginally supporting spacecraft deliveries.
- The large number of hardware changes made during the past year was
affecting costs and schedules.
- Costs forecast for Fiscal Year 1969 exceeded the current LM budget.
Memo, C. H. Bolender, MSC LM Manager, to Manager, Apollo Spacecraft
Program, MSC, "Dr. Mueller's visit to GAEC on July 17, 1968,"
July 19, 1968.
In the continuing effort to reduce costs while still maintaining a
balanced and viable program, ASPO Manager George M. Low recommended to
NASA Hq. that CSM 102 be deleted from the manned flight program. He
estimated total savings at $25.5 million (excluding cost of
refurbishment after the current ground test program). In addition, he
said, during the static structural test program at North American
Rockwell, CSM 102 would be subjected to loads that would compromise
structural integrity of the vehicle for manned flight.
Ltr., Low to Samuel C. Phillips, "Deletion of CSM 102 from the
manned flight program," July 22, 1968.
Prompted by a request from MSC to increase the Saturn V's performance to
46,070 kilograms for lunar missions, Samuel C. Phillips sought to strike
a balance between spacecraft and launch vehicle weight-performance
demands. He established as a new payload interface definition at
translunar injection a payload of 46,040 kilograms. Should the vehicle
per se be incapable of achieving this figure, said Phillips, he would
relax certain flight constraints to achieve the best possible balance
between the space vehicle and the specific mission to be flown. But he
implored both ASPO Manager George M. Low and Lee B. James, Saturn V
Program Manager at MSFC, to work toward this balance between spacecraft
and launch vehicle and to avoid any hardware changes in the Saturn V
solely to meet the new payload interface weight.
Ltr., Phillips to James and Low, "Saturn V Payload Interface
Definition," July 23, 1968.
F. A. Speer, Mission Operations Manager at MSFC, advised NASA Hq. of
plans for S-IVB and spacecraft separation and employment of a
"slingshot" trajectory following insertion into the
trajectory toward the moon. Residuals in the S-IVB, said Speer, could
be used to place the stage in a trajectory that would avoid recontact
with the spacecraft and impact on either the earth or the moon - with
preclusion of spacecraft-launch vehicle collision as the most important
Ltr., Speer to William C. Schneider, Apollo Mission Director, NASA,
"Lunar Debris," July 30, 1968.