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Brown's Lunar Exploration Working Group Michael's Paper on a "Parking Orbit" The Feelings Against Lunar-Orbit Rendezvous The Space Task Group's Early Skepticism President Kennedy's Commitment Houbolt's First Letter to Seamans
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The Space Task Group's Early Skepticism In the early months of
1961, the STG, still at Langley, was preoccupied with the first Mercury flight and the
hope—soon to be crushed by Vostok 1—that an American astronaut would be the first
human in space. When any of its members had a rare moment to consider rendezvous,
it was thought of "as one of several classes of missions around which a Mercury program
follow-on might be built."44 On 10 January 1961, four days after the meeting of the
Space Exploration Program Council, Houbolt and three members of the Theoretical
Mechanics Division—division chief Clint Brown, Ralph Stone and Manuel J.
"Jack" Queijo—attended an informal meeting at Langley with three
members of STG's flight systems division—H. Kurt Strass, Owen E. Maynard,
and Robert L. O'Neal. Langley Associate Director Charles Donlan, Gilruth's former
chief assistant, also attended. It was at this meeting that Houbolt, Brown, and
the others tried to persuade the men from the STG (Donlan had only recently been
reassigned to Langley from the STG) that a rendezvous experiment belonged in the
Apollo program and that LOR was preferable if any realistic plans for a lunar
landing were to be made.45 They were not
persuaded. Although the STG engineers received the analysis more politely than
Max Faget had the month earlier, all four admitted quite frankly that the claims
about the weight savings were "too optimistic." Owen Maynard remembers
that he and his colleagues initially viewed the LOR concept as "the product
of pure theorists' deliberations with little practicality." In essence,
they agreed with Faget's charge, although they did not actually say it, that
Houbolt's figures did "lie." In advertising the Earth-weight savings of
LOR and the size reduction of the booster needed for the lunar mission, Houbolt
and the others were failing to factor in, or at least greatly underestimating,
the significant extra complexity, and thus added weight, of the systems and
subsystems that LOR's modular spacecraft would require.46 This criticism was central to the early skepticism toward
the LOR concept—both inside and outside the STG. Even Marshall's
Wernher von Braun initially shared the sentiment: "John Houbolt
argued that if you could leave part of your ship in orbit and don't
soft land all of it on the moon and fly it out of the gravitational
field of the moon again, you can save takeoff weight on earth."
"That's pretty basic," von Braun recalled later in an oral
history. "But if the price you pay for that capability means that
you have to have one extra crew compartment, pressurized, and two additional
guidance systems, and the electrical supply for all that gear, and you
add up all this, will you still be on the plus side of your trade-off?"
Until the analysis was performed (and there are some former NASA engineers
who still argue today that "this trade-off has never been realistically
evaluated"),47 no one could
be sure—but many NASA people suspected—that LOR would prove
far too complicated. "The critics in the early debate murdered
Houbolt," von Braun remembered sympathetically.48 Houbolt recalls this
January 1961 meeting with the STG as a "friendly, scientific
discussion." He, Brown, and the others did what they could to counter the
argument that the weight of a modular spacecraft would prove excessive. Using an
argument taken from automobile marketing, they stated that the lunar spacecraft
would not necessarily have to be "plush"; an "economy" or
even "budget" model might be able to do the job. One such "budget
model," which the STG engineers did not seriously consider, was one of John
Bird's lunar bugs, "a stripped-down, 2,500-pound version in which an
astronaut descended on an open platform."49 In answer to the
charge that a complicated modular spacecraft would inevitably grow much heavier
than estimated, Houbolt retaliated that the estimated weight of a direct-ascent
spacecraft would no doubt increase during development, making it a less
competitive option in comparison with rendezvous. But
in the end, all the substantive differences between the two groups of engineers
went out the window. All Houbolt could say to the STG representatives was
"you don't know what you're talking about," and all they could say to
him was the same thing. "It wasn't a fight in the violent sense,"
reassures Houbolt. "It was just differences in scientific opinion about
it."50 Whether or not this skeptical
response to that day's arguments in favor of LOR indicated any general STG
sentiment in early 1961 has been a matter of serious behind-the-scenes debate
among the NASA participants. Houbolt has argued that the STG consistently
opposed LOR and had to be convinced from the outside, by Houbolt himself, after
repeated urgings, that it was the best mission mode for a lunar landing. Leading
members of the STG, notably Gilruth and Donlan, have argued that that was not
really the case. They say that the STG was too busy preparing for the Mercury
flights even to bother thinking seriously about lunar studies until after
Kennedy's commitment. Gilruth recalls that when Houbolt first approached him
"with some ideas about rendezvousing Mercury capsules in earth orbit"
as "an exercise in space technology," he did react negatively. It was
a "diversion from our specified mission," according to Gilruth, and
therefore not something on which he, as the head of Project Mercury, had any time
to reflect.51 According to Gilruth, it was only later that he
found out that Houbolt was interested in LOR. By that time, in early
1961, NASA had started studying the requirements of a manned lunar landing
through such task forces as the Low Committee, and the STG did its best
to follow suit. When it did think seriously about a lunar program, especially
about that most critical operation of actually landing astronauts on
the Moon, LOR gained "early acceptance "I was very much in favor of that mode of flight to the
moon from the very beginning," Gilruth has since claimed. "I recall
telling our people that LOR seemed the most promising mode to me—far more
promising than either the direct ascent or the earth orbital rendezvous
modes." The most important thing in planning for a lunar landing program
was to minimize the risk of the actual operation. Thus, LOR was the best choice
among the contending modes because it alone permitted the use of a smaller
vehicle specifically designed for the job. In Gilruth's view, he was always
encouraging to Houbolt. In his estimation, he felt all along that "the
Space Task Group would be the key in carrying the decision through to the highest
echelons of NASA" and "of course, this proved to be the
case."53 Houbolt accepts little of
these assertions; in fact, he "violently disagrees" with them. He
points out that on several occasions in late 1960 he had briefed leading members
of the STG about his LOR ideas. He also asserts that Gilruth had to know about
them, that the STG had ignored and resisted them as too optimistic, and that the
STG would continue to ignore and resist them and insist strongly on the need for
developing large Nova-class boosters for a while. As evidence, he points to many
subsequent instances where his ideas were summarily discounted by the STG and to
different expressions of resistance from key STG members. One such statement
came from Gilruth in an official letter as late as September 1961.
"Rendezvous schemes are and have been of interest to the Space Task Group
and are being studied," Gilruth informed NASA headquarters on 12 September.
"However, the rendezvous approach itself will, to some extent, degrade
mission reliability and flight safety." Rendezvous schemes such as
Houbolt's "may be used as a crutch to achieve early planned dates for launch
vehicle availability," Gilruth warned. Their advocates propose them
"to avoid the difficulty of developing a reliable Nova class launch
vehicle."54 Houbolt felt strongly that
if he could just persuade Gilruth's people to "do their homework" on
rendezvous, "then they too would become convinced of its merits." But
for months, he could not get them—or anyone else—to do that. There was
"virtually universal opposition—no one would accept it—they would
not even study it." In his view, it was "my perseverance, and solely
mine" that caused the STG and various other groups to study and realize
finally "the far-sweeping merits of the plan." It was "my own
in-depth analysis" and "my crusading" based on that analysis that,
above all else, later "paved the way to the acceptance of the scheme."
In Houbolt's view, if not for his constant badgering, NASA might have tried to
reach the Moon some other way.55 In early
1961, when the Low Committee announced its plan for a piloted lunar landing and
its aspiration for that bold mission to be made part of Project Apollo, it
definitely seemed that NASA was still resisting LOR. In outlining the
requirements for an ambitious lunar flight, the committee's chief recommendation
was to focus on the direct approach to the Moon, leaving rendezvous out. LOR was
not discussed at all. Low remembers that during the time of his committee's
deliberations, he asked one of its members, E.O. Pearson, Jr., to visit John
Houbolt at Langley and "to advise the Committee whether we should give
consideration to the Lunar Orbit Rendezvous Mode." Pearson, the assistant
chief of the Aerodynamics and Flight Mechanics Research Division at NASA
headquarters, returned with the answer, "No," LOR "was not the
proper one to consider for a lunar landing." A rendezvous 240,000 miles
from home, when rendezvous had never been demonstrated—Shepard's suborbital
flight had not even been made yet—seemed, literally and figuratively,
"like an extremely far-out thing to do." Maybe LOR would save some
weight; maybe it would not. But even if it did, it was not the best approach; too
many critical maneuvers would have to be made after sending the spacecraft with
its precious human cargo on its lunar trajectory. If any rendezvous had to be
included, it would be much better in the Earth’s orbit, where everything
about the spacecraft could be thoroughly checked out and the craft brought back
safely with its human occupants if something went wrong.56 Thus the Low Committee, in early 1961, recognizing that it
would be too expensive to develop and implement more than one lunar landing
mission mode, made its "chief recommendation": NASA should focus on
direct ascent. "This mistaken technical judgment was not Houbolt's
fault," Low admitted years later, "but rather my fault in trusting a
single Committee member instead of having the entire Committee review Houbolt's
studies and recommendations."57 |
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