"The early trajectory was a parabola, and it was easy to predict where it would be at any point," Johnson says. "Early on, when they said they wanted the capsule to come down at a certain place, they were trying to compute when it should start. I said, 'Let me do it. You tell me when you want it and where you want it to land, and I'll do it backwards and tell you when to take off.' That was my forte."1
Charles Murray, of Bell Curve infamy and legend, has published an astonishing refutation of the story, which emerged from seemingly nowhere in 2016, that long-serving Black NASA Langley mathematician Katherine Johnson single-handedly worked out the math which made possible America’s earliest manned space flights.
It turns out (I am convinced after reading Murray’s critique) the whole thing is one big hoax borne of ego (on the part of Johnson herself), bureaucratic incompetence (on the part of contemporary NASA copy-writers) and ignorance (on the part of those in the lay media who promoted her story, who to a person were unable to see through the holes in technical logic2) — which I must note immediately is a particularly ironic fact, given that the same era that saw Johnson’s rise to fame has seen a rise in skepticism of the moon landings for which she takes so much credit. Yet NASA’s contemporary staff have now yoked the agency’s reputation to this false history (this problem will be discussed in the final segment of this post).
The lore: The calculator-wielding human spaceflight planner
Per the current (September 7, 2023) version of Johnson’s Wikipedia page, which is “semi-locked” and bears a “good article” badge:
Johnson's work included calculating trajectories, launch windows, and emergency return paths for Project Mercury spaceflights, including those for astronauts Alan Shepard, the first American in space, and John Glenn, the first American in orbit, and rendezvous paths for the Apollo Lunar Module and command module on flights to the Moon. Her calculations were also essential to the beginning of the Space Shuttle program, and she worked on plans for a mission to Mars. She was known as a "human computer" for her tremendous mathematical capability and ability to work with space trajectories with such little technology and recognition at the time. […]
As a computer, she calculated the trajectory for Alan Shepard, the first American in space...John Glenn requested that she personally recheck the calculations...before his flight aboard Friendship 7...on which he became the first American to orbit the Earth. — NASA [Note that the linked NASA page does not contain this phrasing.]
The citations on her wikipedia page give a picture of the depth of documentary evidence that grounds the claims of the importance of her work.
Many, such as the second paragraph above, are sourced to NASA promotional materials which were authored decades after her retirement, and therefore do not constitute primary documentation of any role she played in these programs from Langley and cannot be said to make up for the absence of the same. It is still worth noting here that NASA’s online materials strongly affirm all points of the lore (again, without constituting in any form direct evidence).
The majority of the remainder of citations on her page for claims regarding her work are to media write-ups after she became a celebrity at age 96; these do not appear to contribute anything except occasional added testimony from Johnson and Hidden Figures author Margot Lee Shetterly.
References older than this, and the general picture of how Johnson’s claims came to be so widespread, will be discussed further below (a treatment of this subject is also provided in Murray’s critique). Essentially, everything before 2015 consists of prior publications of Johnson’s claims that received more limited attention; none of them have any source beyond Johnson herself. For comparison, here is a segment from wikipedia’s archive of her page as of February, 27, 2015:
Hidden Figures not coincidentally was published one year after Johnson was awarded the Medal of Freedom in November, 2015 (why it was not coincidental will be discussed below, in “How it came about”). This provides two alternate contemporary references for the Johnson lore, her award biography and a concurrently-published NASA statement.
From the former, i.e. her Medal of Freedom biography (emphasis added):
With her razor-sharp mathematical mind[…] From sending the first American to space, to the first moon landing, she played a critical role in many of NASA’s most important milestones.
From the latter, in the statement authored by NASA Deputy Administrator Dava Newman (emphasis added):
For Katherine, finding the ‘why’ meant enrolling in high school at the age of 10; calculating the trajectory of Alan Shepard’s trip to space and the Apollo 11’s mission to the moon; and providing the foundation that will someday allow NASA to send our astronauts to Mars. She literally wrote the textbook on rocket science.
This is to round out the picture of how the legend, as it emerged into the general consciousness after 2015, stands at a first glance. By all accounts, Katherine Johnson was a mathematical prometheus responsible for making America’s greatest scientific milestones even possible, and at a time when computers were (somehow) untrustworthy to do the same. One seemingly sees the astonishing nature of discovering this legend in real-time when Obama’s head and stance veer rightward at the words “sending the first American to space.”
The truth: Humans cannot plan space flights with calculators
It bears remarking that should all of Johnson’s claims regarding her role in NASA mission development be false, it would remain true that she was a trailblazer whose life can be considered noteworthy in the context of the 20th Century American Civil Rights psychodrama, and that she coauthored a paper which made a contribution to the overall space program, in which difficult math was used. In the first point however it would still be the case that, both in being Black and a woman at NASA and its predecessor, she was among others. Regarding Hidden Figures, the removal of the outlandish and technically impossible claims regarding her math would not render meaningless her career in general nor that of her coworkers.
Nonetheless, there is an astonishing amount of daylight between the Johnson lore, what was actually documented regarding NASA missions, as well as what is even technically plausible. And in light of this fact, it seems inappropriate for Johnson to represent the face of and receive the bulk of recognition for first-generation minority NASA employees. If she should receive a Medal of Freedom, all of them should.
Murray’s document begins with two critiques sent to him by Hal Beck and Ken Young, both of whom were involved in trajectory development and analysis in Houston during the Gemini and Apollo era, and in Beck’s case also working alongside Johnson at Langley in 1959-61, which pertains to the early Mercury era — this covers all of the missions for which Johnson’s math is now given complete credit.
A basic summary of Beck and Young’s technical critique
Planning long orbital missions and especially orbital rendezvous requires complicated algorithms which build on 3-degrees-of-freedom equations to model for the myriad physical properties of celestial objects and space craft, which in turn requires computers running the same algorithms. While one can design (theoretical) orbital trajectories manually according to mathematical theory (two-body equations), in other words, higher-order algorithms that take into account gravitational irregularities, drag, etc., are required to develop (plan) and execute long orbital missions. Moving beyond the limitation, imposed by the limitations of calculators, of using simplistic two-body equations was specifically and deliberately taken up as part of the NASA Space Task Group Mission Analysis Branch’s effort to develop Mission Planning Capability.
Development of the program in question (in terms of planning missions), CO3E (run on an IBM 7094), did occur in Langley (in 1959, three years before Glenn’s flight), but took place under John Shoosmith as a computer software development program and did not involve Johnson in any form. Johnson was not part of the Space Task Group responsible for building manned Mission Planning Capability.3 And, to repeat, this capability depended on developing the computer program — a “high-fidelity trajectory simulation package” that “was impossible to for Katherine to run […] on her Friden calculator,” per Beck, p17. It may be noted that there were women who worked on math in the Space Task Group MPAD (Mary Shep Burton, Catherine T. Osgood, and Shirley Hunt Hinson); just not Johnson.
A Friden calculator from 1950.
Nonetheless, it was naturally the case that NASA employees, contractors, enthusiasts, etc., if versed in the simpler two-body equations, would at times attempt or be asked to attempt to replicate mission parameters — this was not in any way “checking” the CO3E algorithms which had actually planned and run the missions; it was more like checking the simpler, manual equations to see if they were in any way accurate. This would appear to be the nature of the request for Johnson to produce a model of Glenn’s Mercury-Atlas 6, if such a request ever happened. To be clear, any manual “determination” of a mission plan as a category can not have anything to do with how any actual mission plans were developed, and so all claims that Johnson developed plans with hard math (rather than frivolously approximated them after the fact) are nonsense.
Johnson’s oft-repeated claim of determining launch times based on desired landing sites reflects unfamiliarity with the planning process for the manned missions. Besides relying on computer simulations as already discussed, precision was not always necessary or achievable in complicated missions. “Early on, when they said they wanted the capsule to come down at a certain place, they were trying to compute when it should start,”4 again merely describes the limits of manual modeling that computers allowed NASA to transcend. Manned missions in planning and execution were more flexible, including in terms of launch times and landing areas.
Johnson’s co-authored 1960 manuscript, “Determination of azimuth angle at burnout for placing a satellite over a selected earth position” (TN D-233), is a work of manual labor considering a launch an abstract sense with two-body equations, but was not used to directly inform any NASA missions — instead, per Beck and Young, it was undertaken as part of the design process for the on-the-ground tracking network. Crucially, no special importance was ever attached to the paper by coauthor Skopinski.
Finally, all the maths that can be done manually, such as the two-body equations used by Johnson and Skopinski in “Determination…”/TN D-233, were well-established even before the space age was underway. They are not something that would have required any one irreplaceable genius to figure out; nor would they have been undertaken outside of the Space Task Group in the event that they alone, rather than Shoosmith’s CO3E program, were in any way involved in mission plannings, unless as part of a signed contract.
“Tldr,” manual flight trajectory analysis was obsolete by the era of manned missions.
Murray’s summary repeats some of these points, undoubtedly more precisely than I have, and anyways in the case of technical discussion it is helpful to offer the reader alternate wordings (emphasis in original):
“Two-body” mathematics expresses the relative motion of two bodies in space, ignoring external forces. Forest Ray Moulton had developed the basic mathematics for solving two-body problems in An Introduction to Celestial Mechanics published in 1902 and updated in 1914. As of 1959, some of the Germans who worked at Redstone Arsenal under Werner von Braun had been calculating two-body trajectories since 1936.
American aeronautical engineers had been calculating trajectories since the first Redstone missile launch in 1953 and had already moved beyond two-body mathematics to trajectory integration—the process of integrating the equations of motion of a spacecraft to determine its position and velocity as a function of time. The integration process takes into account specified external forces or perturbations acting on the spacecraft. In the Mission Analysis Branch, John Shoosmith was preparing a high-fidelity trajectory simulation in CO3E for the Mercury missions months before KJ had completed the draft of TN D-233.
What did TN D-233 mean for the manned spaceflight program? For Hal Beck and Ken Young, the algorithms that were later published in TN D-233 were useful for a parametric study of site-selection for Project Mercury’s tracking network. Their understanding was that Skopinski had developed the algorithms specifically for that purpose. The analyses related to the site selection process had nothing to do with the launch, orbital, and entry trajectories in mission planning for the Mercury flights.
Ted Skopinski, the lead author, was a long-time colleague of both Beck and Young. He never even mentioned TN D-233 or its algorithms to either of them. KJ is the only person at Langley or with the MSC who is known to have thought that TN D-233 was even relevant, let alone essential, to the software used for the Mercury missions.
This, again, is all just a brief summary. Beck’s account fleshes out for the reader the developmental history that led to the Space Task Group and that group’s Mission Analysis Branch, so that it can be understood as distinct from the general remit of NASA Langley and Langley’s human “computers,” including Johnson (who helped train him on the Friden calculator when he first joined at Langley).
Young’s “Footnotes” are more technically critical, especially regarding Hidden Figures author Shetterly’s depiction of Johnson’s account of historical missions — it is clear that Johnson’s memories in her 90s do not correspond to actual events or possibilities, and that Shetterly’s book was written and published in absence of any editorial input from spaceflight history experts (Shetterly solicited input from Beck four months before publication, resulting in an exchange of questions and comments, but no changes were made in response).
Finally, Murray’s essay offers his own appraisal and argument for the case that Johnson did not design or provide the math for mission planning. In particular regarding the claim that Skopinski and Johnson’s TN D-233 report was required and incorporated for the CO3E program, Murray submits that this is falsifiable via NASA archive documentation, and appears likely to be falsified given that the math in TN D-233 is not of the sort required for a functional computer simulation, so we can presume it would in the course of further investigation be falsified.
The lore vs. the book
I have left out much of the critique, as it centers on aspects of Shetterly’s depiction of events that are a bit extraneous to the Johnson lore, i.e. to the general soundbite that “From sending the first American to space, to the first moon landing, she played a critical role in many of NASA’s most important milestones.”
For example, Shetterly’s narrative (she appears to have tried to make sense of things as best she could without expert input) suggests that although TN D-233 was purportedly seminal for the computer simulation, no one including the astronauts trusted the computers to run the same program, and so John Glenn refused to get in the driver’s seat unless Johnson re-checked the computer-developed flight plan with a day and a half of work (which, depending on one’s chosen time intervals, is about what it would take to produce a less accurate manual model of the mission). In turn, Beck and Young protest that the high-trust, chain-of-command-based work culture at NASA render such a tale flatly implausible. But, the entire point about Glenn placing the demand (as in the 2017 NASA biography for Johnson) vs. a nebulous “they” placing the demand (as in most other NASA news items published since 2015) is extraneous to the core of the legend.
In general, Shetterly’s book does not appear to be responsible for nor to determine the shape of the Johnson lore — a conclusion which Murray himself reaches at the end of his essay, despite structuring the entire thing as a challenge to Shetterly’s book.
For this reason I have also left out, until now, many of the frankly stunning vulgarities in Shetterly’s prose that are quoted by Young. I did not wish to prejudice the reader based on these stylistic quirks, because to a great extent the most responsible party in propagating the Johnson legend are the authors of modern statements regarding her at NASA. Broadly, I am not interested in anything in the book that hasn’t penetrated the general consciousness.
Still, the context of Hidden Figures should be mentioned — Johnson was nearing 91 years old when Shetterly decided to write the nonfiction book which would incorporate her story, discussing historical events of a highly technical nature which no lay author should discuss without consulting experts.5 From this starting point she appears, from the way she attempts to convey orbital mechanics to the lay reader, to have tried to figure much out for herself using other lay sources. The results help to make clear how much credulity was extended to the elderly Johnson without merit; and so excerpts are included in the footnotes.6
How it came about
If Johnson’s story of her math enabling the earliest manned American space missions is a hoax, who is the author?
One is tempted to imagine that her claims were the result of advanced age and attendant unreliable memory and susceptibility to suggestion — which would place much of the responsibility on Shetterly as well as upon the credulous media reception of Hidden Figures’ revisionist account of NASA history. But this fails to account for why Johnson was given the Medal of Freedom the November immediately before the book came out.
There are a few obvious ways to investigate this problem, which quickly produce the solution: Johnson has always been making these claims, but was more frequently given an audience in the 2000s thanks to the internet, gradually resulting in her crossing the event horizon into celebrity. The claims do expand in scope in her later years to include her supposed crucial roll in the Apollo program, but this is not surprising. In investigating, Murray appears to have gone with a newspapers.com search building off of Hidden Figures references; I started (before reaching the end of his critique) with looking into the edit history of her wikipedia page.
First, Murray’s results, with his brackets accredited:
TN D-233 did not slowly take on inflated importance to KJ as she reached old age. She saw it as vitally important from the beginning. Contemporaneous evidence can be found in two newspaper articles about KJ’s role in the manned spacecraft program cited in Hidden Figures. The first is an article apparently published soon after Alan Shepard’s flight in a major black newspaper of that era, the New York Amsterdam News. Shetterly quotes it in Hidden Figures:
They [unnamed people at NASA — Murray] are loud in their praise of a young West Virginia-born Negro girl who has prepared a science paper that was not only a key document in the flight of Commander Shepard into outer space but which will actually become “THE” key document if and when we are able to put an astronaut into orbit.18 [Capitalization in the original — Murray]
[…]
The second contemporaneous source is an article in a black weekly newspaper, the Pittsburgh Courier, printed under the headline “Lady Mathematician Played Key Role in the Glenn Space Flight” and with the subhead “The Story of Katherine Johnson.” The date was March 10, 1962, 18 days after the flight of MA-6.[…]
Here is the full text of the section that Shetterly summarized:
Mrs. Johnson is credited with helping to devise the highly complex tracking system which enables scientist to predict...within TWO miles, the location of Lieut. Col. Glenn’s rocket cone upon his return to earth after three orbits around the world.
Murray identifies two more publications from 1977 and 2008, speaking to a long period of obscurity before the internet era. This brings us to the inception of her Wikipedia page, which took place at the very end of 2009. I have already shown a screen-grab of how the page stood in early 2015 — it contains the essence of her legend as was popularized the next year. The following constitute all citations for the page at that date (duplications and invalid entries removed):
NASA TND-233, “The Determination of Azimuth Angle at Burnout for Placing a Satellite over a Selected Earth Position” 1960. Authors: T.H. Skopinski, Katherine G. Johnson
Absent are any direct sources, i.e. NASA development and planning documents, which can justify the claims Johnson makes regarding the relevance of her work or of TN D-233 specifically. This, to be fair, is not entirely unusual for a wikipedia page concerning an individual in the space program — even if online-archived NASA documents regarding their work are abundant, personal pages will not cite these documents as frequently as do the pages for missions and craft.
This is still sufficient to demonstrate that Johnson had a nascent internet footprint in early 2015 which was based on nothing but her own testimony (as reported in the oral history page and in Hodges’s NASA news item); and that this testimony already made all the substantial claims that constitute her legend today. It is not a wild leap to imagine that the above trickle of interest was on its own enough to prompt both her inclusion in Shetterly’s book as well as her Medal of Freedom nomination.
Murray hypothesizes, plausibly, that Johnson’s inflated estimation of her work’s importance reflects and derives from the fact that the work was important to her. That her unsubstantiated claims of grandeur have been received so uncritically by the media and the American public, meanwhile, reflects a certain cultural need to only allow and accept two possible roles for Black Americans, either the denigrated victim whose failures are a result of systemic forces, or exceptional individuals of impossible virtue. Murray remarks that even Shetterly herself observes this dynamic at work in Johnson’s case:
For too long, history has imposed a binary condition on its black citizens: either nameless or renowned, menial or exceptional, passive recipients of the forces of history or superheroes who acquire mythic status not just because of their deeds but because of their scarcity.
None of this media and cultural preconditioning is Shetterly’s doing, and so (especially given that Johnson’s claims were all now already online) it is perfectly easy to imagine that the Johnson myth would have taken on viral status in 2016 even without the book. It is not out of character that the outlandish claims which won Johnson her Medal of Freedom — “From sending the first American to space, to the first moon landing, she paid a critical role in many of NASA’s most important milestones” — would have self-amplified in complete absence of critical investigation in the “fake news” age.
The conspiracies of speech and silence
And this brings us to NASA, past and present.
In the present — in the post Medal of Freedom era — it is NASA which acts as the primary affirmative perpetrator of the hoax, in the form of the 2015 statement issued after Johnson’s Medal of Freedom, her biography page, and a continual feed of news publications that recycle her legend.
The latter in many cases seem like the type of intern-adjacent copy generation soon to be replaced by AI, divorced from any critical capacity from a technically knowledgeable perspective. The former — “NASA Statements on Katherine Johnson’s Medal of Freedom” — well, our authors are two high-ranking Obama appointees…
But what of the older generation of NASA — those who were alive and employed during the conquering of the frontier, who must have spotted and understood immediately this implausible nature of the Johnson legend?
Murray writes:
As for why none of the people who were in a position to know the truth spoke up, we already have answers. As Ken Young said in his initial email to me in December 2016, the MSC veterans in Houston had been trying to decide what to do since the Presidential Medal of Freedom had been announced in 2015. They finally decided to keep quiet. One of the reasons was that KJ was alive and in her late nineties. No one wanted to spoil it for her—a very human and appropriate reason to keep quiet. Another reason was that discrediting the claims made for KJ’s contributions would attract accusations of racism and sexism that could easily get national publicity—an unpleasant prospect.
In this sense the position of NASA is understandable, both from a perspective of modern incompetence and diversity hire tokenism and the reluctance of the old guard to buck political headwinds.
But it still remains the case that NASA is now engaged in a conspiracy to perpetuate a mythical version of its own history — exactly as is claimed by lay skeptics of its accomplishments in the space race. The organization, to preserve credibility, has from this stance only one choice, today and forever: It can never acknowledge that Murray, Beck, and Young are right, and the Johnson legend is ridiculous.
And would not have in any sense farmed out or “bootlegged” the math from outside of the Mission Analysis Branch (later Mission Planning and Analysis Division); any involvement of Langley outside of STG would have been and was documented as formal, signed task assignments. “During Mercury, no planning products were developed from groups outside the Mission Analysis Branch,” per Beck, and this cloistering of the planning process was essential to prevent the introduction of un-documented changes to any element of the plan (p 13.) “If anything involving trajectory planning had been outsourced to anyone working with Katherine Johnson, it would have been documented.”
In the case of hyper-idealized “flights” that remain bound to earth, launch time as far as I can see is irrelevant to landing area anyway — just as a string tied from a given point on a ball would, if wrapped around the ball in a given direction, end at the same point at any time of the day.
Appendix A: Excerpts from Hidden Figures, as sourced by Young (except the final quote, highlighted by Murray):
To the engineers on Katherine’s desk fell the responsibility of the trajectories, tracing out in painstaking detail the exact path that the spacecraft would travel across the surface from the second it lifted off the launchpad until the moment it splashed down in the Atlantic.
Successful orbital flight required the engineers to adjust the tennis ball machine’s chute to the correct angle and arm its launcher with enough force to send the ball up through the atmosphere and into an orbit around Earth on a path so precisely specified, so true, that when it came back down through the atmosphere, it was still within spitting distance of the navy’s waiting racket.
Once she had worked out the math for the test scenarios on her calculating machine, substituting the hypothetical numbers for variables in the system of equations, the Mission Planning and Analysis Division within the Space Task Group took her math and programmed it into their IBM 704.
She worked through every minute of what was programmed to be a three-orbit mission, coming up with numbers for eleven different output variables, each computed to eight significant digits. It took a day and a half of watching the tiny digits pile up: eye-numbing, disorienting work. At the end of the task, every number in the stack of papers she produced matched the computer’s output; the computer’s wit matched hers.
The first two are misapprehensions of the flexibility and imprecision of longer orbit missions (all manned missions), as already detailed. The latter two are simply an absurd proposition; NASA used computers that couldn’t solve an equation, but then also that could? This gives a sense of how Shetterly was elaborating on Johnson’s own claims without understanding what was wrong about them.
The rest of my excerpts are the aforementioned “vulgarities;” to a certain extent they disqualify Shetterly’s book as historiography and place it in the category of paternalistic propaganda, fulfilling and replicating the American “Magic Negro” trope to the word. Brackets are from Young.
Like her fellow West Virginian John Henry, the steel-driving man who faced off against the steam hammer, Katherine Johnson would soon be asked to match her wits against the prowess of the electronic computer.
The astronauts, by background and by nature, resisted the [electronic] computers and their ghostly intellects.
The human computers crunching all of those numbers—now that the astronauts understood.
He [Glenn] did, however, trust the brainy fellas who controlled the computers. And the brainy fellas who controlled the computers trusted their computer, Katherine Johnson. It was as simple as eighth-grade math: by the transitive property of equality, therefore, John Glenn trusted Katherine Johnson.
Some of their briefings with the brainy fellas had happened upstairs, though she was not invited to attend those meetings. That John Glenn didn’t know, or didn’t remember, her name didn’t matter; what did matter, as far as he was concerned—as far as she was concerned—was that she was the right person for the job.
But this last step, with its complicated dance between the Moon and the lander and the waiting command module, was the most complicated. Katherine Johnson had given her best to her part of the grand puzzle, of that she was sure. The day was soon coming when the world would see if her best, if the brainy fellas’ best, if NASA’s best, was good enough.
Katherine knew better than anyone that if the trajectory of the parked service module was even slightly off, when the astronauts ended their lunar exploration and piloted their space buggy back up from the Moon’s surface, the two vehicles might not meet up.
The command service module was the astronauts’ bus—their only bus—back to Earth: the lander would ferry the astronauts to the waiting service module and then be discarded. If the two vehicles’ orbits didn’t coincide, the two in the lander would be stranded forever in the vacuum of space.
Each leg carried the specter of the unknown; only after their landing matched the numbers of her equations, when they had been plucked from the ocean and cosseted in the waiting navy ship, would she be able to exhale.
The newspaper recounted the lady mathematician’s background and accomplishments with pride, detailing the report that sent Glenn’s rocket cone whizzing through the sky. Katherine accepted the recognition graciously: all in a day’s work.
Wikipedia does not use primary sources, only secondary sources. Yes, I know. This puts them at risk of repeating gossip, but it also takes them out of the realm of interpreting primary sources. They need only to repeat what secondary sources have written to avoid this trouble.
The problem I have with the 9/11 truther movement is that some fraction of whatever compendium of "evidence" is being presented will align with my professional experience, and I will not see anything suspicious in the facts presented. For example, I fully believe, based on my field of experience, that someone with simulator and general aviation flight experience would be capable of piloting an airliner into a large building.
Too many threads and red herrings. I do think there are "conspiracies" behind 9/11. Primarily regarding who knew what, when, and why they did or did not do anything with that knowledge. But a lot of these little "nuggets" people latch onto seem to be dead ends, and should be retired, pending further evidence.
Wikipedia does not use primary sources, only secondary sources. Yes, I know. This puts them at risk of repeating gossip, but it also takes them out of the realm of interpreting primary sources. They need only to repeat what secondary sources have written to avoid this trouble.
The problem I have with the 9/11 truther movement is that some fraction of whatever compendium of "evidence" is being presented will align with my professional experience, and I will not see anything suspicious in the facts presented. For example, I fully believe, based on my field of experience, that someone with simulator and general aviation flight experience would be capable of piloting an airliner into a large building.
Too many threads and red herrings. I do think there are "conspiracies" behind 9/11. Primarily regarding who knew what, when, and why they did or did not do anything with that knowledge. But a lot of these little "nuggets" people latch onto seem to be dead ends, and should be retired, pending further evidence.