Tuesday, November 3, 2026

Refinery Modeling and Simplex

The growth of computing for optimizing refinery operations was rapid. In Houston, John Bonner and Joe Moore were chemical engineers at Humble Oil’s Baytown refinery. With Simplex, by 1956 they had formed one of the earliest consulting firms dedicated to software applications and were leading the refining industry into the era of linear optimization with early mainframes like the IBM 650. To trace these developments backwards, at Humble they had full access to communications across what would become Exxon, including those from Gifford Symonds. Symonds had been circulating technical memos about Simplex and refining since 1953, and in 1955 these were collected and published by the company in the landmark 74-page hardcover monograph “Linear Programming: The Solution of Refinery Problems”. This was not only one of the first practical books about modeling and simulation using computers, it was effectively one of the first about computational linear algebra and computer programming. By developing domain-specific software tools such as the Refinery and Petrochemical Modeling System, alongside the Gamma matrix generator and report writer, Bonner and Moore automated matrix assembly and problem translation, building the example problems and framework of Symonds into routine computing practices across the refining industry. [1]

Symonds was effectively the conduit to chemical engineers and refinery specialists of the advances around Simplex and linear programming while he was actively collaborating with two leading researchers who would work at UT Austin from the seventies, Abraham Charnes and William Cooper. All three played important roles, alongside Dantzig, for the growth of Simplex in refining, beginning with aviation gasoline blending in 1952 and vertically-integrated operations in the oil industry in 1954. The story traces back to 1949, when the economist Cooper shared early drafts of Dantzig's Simplex method with the mathematician Charnes, and they simultaneously began working with Bob Mellon at Gulf Oil to eliminate "octane giveaway" in refinery blending operations. Their collaboration was defined by a commitment to let real-world operating complexities drive theoretical advances. In formulating the aviation gasoline blending model, Charnes and Cooper encountered the issue of mathematical degeneracy in Dantzig's algorithm, leading Charnes to formulate perturbation methods to ensure convergence. [2][3]

The period from the 1952 gasoline blending work of Charnes and Cooper to the 1955 book by Symonds saw the dawn of a major market for computer modeling in the refining industry, one that helped drive the commercial growth of the computer industry, with significant amounts of early computing power going directly into the oil industry. This work showed corporate management that linear programming was a practical tool with direct financial returns, creating the early commercial demand that justified major corporate investments in computing. Over the next several years Charnes and Cooper teamed with Symonds to pioneer methods for weather-sensitive heating oil distribution and handling uncertainty within the context of linear programming and the computing limitations of the era. The relocation of Charnes and Cooper to UT Austin was orchestrated by the business and economics departments as part of creating a major center for quantitative analysis, computer modeling, and commercial technology transfer. In 1968 Charnes established the Center for Cybernetic Studies as a primary research hub for mathematical programming and logistics, with Cooper joining in 1980. 

The UT Austin Center for Cybernetic Studies was designed as a quantitative, numerical modeling expansion, with interdisciplinary research bridging applied mathematics, computer systems, and large-scale organizational decision-making. The term "cybernetics" reflected the intellectual framework of post-war systems research, focusing on communication and control across complex human, mechanical, and informational networks. In practice, Charnes directed the center toward what he termed "extremal methods", the rigorous application of optimization and network flows to logistical and operational bottlenecks. A dominant share of funding came from military and federal agencies. The center tackled problems ranging from maritime logistics and sealift deployment to personnel assignment and environmental resource management, such as marine spill response plans. Center researchers established close collaborative ties with applied mathematicians and operations researchers across Texas, frequently publishing joint work with Darwin Klingman at UT Austin on network simplex algorithms and Robert Thrall at Rice University on efficiency analysis and game theory.

The maximum-profit refinery problem, adapted by Symonds as chapter three of his 1955 book from earlier work by Charnes and Cooper, captures the delicate balancing act at the heart of refinery management. A plant manager has four crude oils A, B, C, and D on hand, each arriving in limited weekly quantities. Crude C offers an operational choice: it can be routed through a standard fuel setup or tuned to extract specialized lube distillate, giving five possible ways to run the plant. Every run cracks the oil into a different mix of four finished products, gasoline, heating oil, lube distillate, and fuel oil, each carrying its own margin per barrel. The operational challenge lies in the boundaries. On the supply side, crude availability is strictly capped by weekly deliveries. On the market side, customer demand sets an upper limit on how much of each fuel can be sold. Crucially, these product targets are ceilings rather than mandatory quotas. If processing another barrel yields low-margin products that fail to cover their costs, the refinery simply leaves that demand unmet rather than chasing volume for its own sake.

To navigate these trade-offs, the Simplex method begins with the plant entirely idle, running no crude and leaving all market demand unfilled. At each step, it answers a fundamental question: which operation adds the most profit per barrel? The algorithm ramps up that run until it strikes an immediate physical bottleneck, either an empty crude tank or a saturated product market. Once a constraint binds, the method brings in the next most attractive run to rebalance throughput, continually substituting one operational path for another. When no further substitution can improve the margin, the refinery settles into an optimal rhythm. Every barrel of market demand for gasoline, heating oil, and lube distillate is satisfied, while leaving a slight shortfall of barrels in fuel oil where additional processing would erode net returns. The resulting balance generates roughly $67,830 in weekly profit, offering an early, definitive demonstration of how linear programming could turn raw operational constraints into disciplined economic strategy.

Home of the Center for Cynernetic Studies, the business and economics building, built 1963. A focal point for operations research and Simplex. By the eighties, there was a DEC-20 in the basement, along with IBM machines.
A TRW RW-300 computer integrated with a refinery in 1959. [4]

[1] Symonds, Gifford H. Linear Programming: The Solution of Refinery Problems. New York: Esso Standard Oil Company, 1955.

[2] Charnes, Abraham, William W. Cooper, and Bob Mellon. "Blending Aviation Gasolines—A Study in Programming Interdependent Activities in an Integrated Oil Company." Econometrica 20, no. 2 (1952): 135–59.

[3] Charnes, Abraham, William W. Cooper, and Bob Mellon. "A Model for Programming and Sensitivity Analysis in an Integrated Oil Company." Econometrica 22, no. 2 (1954): 193–217.

[3] AVEVA, "The Day a Computer Took Charge of a Texas Refinery," Our Industrial Life, October 16, 2026. TRW is a recurring theme here. In 1958 David Young moved from TRW to UT Austin to help found the Computation Center. 

Simplex Time Capsule is evolving here.

Saturday, October 24, 2026

Humble Oil Research, Houston

The appearance of the IBM CPC in the context of Houston and reservoir modeling during the early fifties leads backwards into the history of technology at Humble Oil. Humble was among the earliest adopters of new technologies, notably reflection seismology and the use of microscopic fossils in core samples to correlate rock strata across Texas and Louisiana. Humble researchers such as Thomas Moore and Stuart Buckley helped establish the physical principles governing how oil, gas, and water move underground under pressure, and their work shifted drilling from rapid, wasteful extraction to controlled pressure management, dramatically increasing long-term field recovery rates. Moore joined Humble in the late twenties and quickly rose to head the company’s Production Research Division in Houston, recruiting chemical engineers, physicists, and mathematicians from universities like MIT and Caltech, establishing Humble as a corporate research center on the level of Bell Labs and DuPont. 

Humble built its flagship Baytown Refinery near Houston and it quickly became a testbed for modern chemical engineering. During World War II, Humble’s Baytown operations were essential to the Allied war effort. Humble pioneered processes for producing high-octane aviation gasoline and synthesizing toluene for TNT, and collaborated with Standard Oil researchers to deploy and scale fluid catalytic cracking processes for breaking heavy crude fractions into high-value motor fuels at unprecedented yields. Baytown became an early model for integrated refinery-petrochemical complexes, manufacturing butyl rubber, synthetic solvents, and specialized lubricants. In the fifties and sixties, Humble was an early corporate adopter of mainframe computers to run both reservoir simulations and complex linear programming models for refinery optimization. Humble’s technological footprint extended directly into space exploration. In the late thirties, Humble purchased the 30,000-acre West Ranch near Clear Lake Texas. In 1961, Humble donated a 1,000-acre parcel of this land to Rice University, which then deeded it to the federal government for the construction of NASA’s Manned Spacecraft Center, renamed the Johnson Space Center in 1973. The remaining acreage was developed into the Clear Lake City master-planned community and the Bayport Industrial District, explicitly designed to support space and chemical technology industries.

Miles Leverett was one of Moore’s chemical engineering hires from MIT in 1938, where at the same time Richard Feynman was completing his studies in physics. Leverett was soon at the forefront of important work on reservoir modeling at Humble, and the resulting Buckley-Leverett equation remains a well-known landmark today. In 1942, Leverett’s boss Moore seemingly vanished from Houston, and soon Leverett himself received the call to follow Moore into the Manhattan Project. This was the soon familiar pattern experienced by others at the time, including Feynman who headed west to Los Alamos, with Leverett crossing his path headed north to Chicago and Enrico Fermi, where he was present on December 2, 1942 when the first nuclear reactor achieved a sustained chain-reaction. Leverett and Fermi became co-holders of the fundamental patents for the type of reactor developed in Chicago and soon put into production at Oak Ridge Tennessee. The paths of Leverett and Feynman crossed again at Oak Ridge, where Leverett was leading the production efforts and Feynman visited as the nuclear safety representative of Los Alamos. 

What is of special interest in these events is the parallels between the work at Humble and Los Alamos. Both were concerned with the modeling and simulation of fluids, diffusion processes, and heat or energy flows. These were computationally demanding topics on the frontier of what was possible at the time, and naturally led to a broad similarity in computing efforts. The role of the IBM CPC and its precursors at Los Alamos and Humble reflects this fundamental symmetry, and the parallels only increased during the fifties, with the thermonuclear simulations at Los Alamos and the reservoir simulations and birth of the ADI method on Humble's CPC. The essential nature of fluids is that they are the opposite of solids, they can not resist deformation. Solids are static, in contrast with the highly dynamic phenomena encountered in fluids. This is the physical root of the computational challenges that drove advances in modeling and simulation at Humble and Los Alamos. An interesting question is whether Moore and Leverett's work in the Manhattan Project had an influence, later, on Humble's acquisition of a CPC. Certainly the simulation work done on the CPC precursor at Los Alamos was leading-edge, and likewise for the work done later on the CPCs at RAND and Humble. For the CPC's seemingly modest hardware, there was an impressive record of tackling challenging problems. Here's Peaceman discussing the 604 calculator, the digital heart of the CPC.

So that was the state of reservoir modeling when I came to work at Humble in 1951. We had nothing that you could call a computer. We did have access to some accounting machines that the accounting department would let us use, but only at night. Henry Rachford had come to work a year before me and was already playing with an accounting machine called the IBM 604. He, along with the managers of the Production Research Division of Humble, had the vision to see that digital computation was going to be the way to do reservoir modeling and that by using finite-difference methods to solve partial differential equations, we could overcome the limitations of the analytical methods. We wanted to be able to include nonuniform properties, arbitrary geometry, and nonlinearities in the differential equations. ... When I came to work, Henry Rachford and John Rice were already at work on this problem, trying to use the accounting machine, the IBM 604. Let me try to describe this gadget to you. It was called a multiplying punch, and the only input/output that it had was a card reader and card punch. It could only handle fixed-point decimal numbers, with no alphabetic information. The way the accountants used it, say for a payroll application, would be to have some numeric data already punched on each card, such as an employee's identification number and salary. Each card would be read at the read station and would then travel to the punch station. On the way, the marvelous electronic multiply unit would calculate the withholding and social security taxes, subtract them, and then punch the taxes and take-home pay into the blank space on the card. After being punched, the card would then travel to the stacker. To see the results printed, an operator would have to carry the deck of cards to another machine to print the results. The electronic multiply unit was really quite flexible, but programming it was done in a way that we would now consider quaint. There was a board with a lot of holes, and this board could be placed into a holder with terminals in the back. Programming was done by plugging wires from one hole to another. Down one side of the board was a series of holes called program steps. On the other side were holes for various functions, such as reading from a card into electronic registers, adding or multiplying the contents of two registers together, and punching the contents of the registers onto the card. Remember that in those days, all the electronics were done with vacuum tubes. [2]

Humble Oil Research Center at Buffalo Speedway, near Rice and River Oaks, 1955. [1]
IBM 604 multiplier, also referred to as the 604 calculator. Multiplication was via digital logic using vacuum tubes. Numerical representation was binary-coded decimal. This was essentially the heart of the IBM CPC, and what made the CPC a digital system. [2]
[1] Hanly, Jack B. "Building Houston's Petroleum Expertise: Humble Oil, Environmental Knowledge, and the Architecture of Industrial Research," Southwestern Historical Quarterly 128, no. 1 (2024): 63–83.

[2] Peaceman, Donald W. 1990. "A Personal Retrospection of Reservoir Simulation." In A History of Scientific Computing, edited by Stephen G. Nash, 106–29. New York: ACM Press / Addison-Wesley.

Saturday, October 17, 2026

Fluids, Heat, and Linear Algebra in 1950

In 1944 Los Alamos was focused on fluids and heat transfer, the same types of problems worked by Humble Oil and David Young in the following years. Stan Frankel became the first patient infected with "the computer disease" at Los Alamos, a diagnosis created specifically for Frankel by Richard Feynman. The first photo of this post shows the Los Alamos technical area and Building E, housing both the hand calculators of GroupT-5 and the IBM punched card machines of Group T-6. [1][2]

Whether simulating the conditions in a nuclear reactor, or a subsurface reservoir, or a reentry heat shield, fluids and heat meant spatial fields, flow, and harmonic boundary value problems. In practice, with a computer, this meant matrix and vector linear algebra for large systems of equations, and the period around 1950 marked the dawn of modern linear algebra. There was a direct connection between the fluid dynamics simulations at Los Alamos and at Humble, and the initial breakthroughs happened on essentially the same punched card machines. A span of ten years passed, from 1944 to 1954, while the computing hardware remained within the IBM CPC lineage, and this is the historical legacy that Al Matsen brought from Humble to Welch Hall in 1958.  

Young and Frankel published the independently created iterative SOR Successive Over-Relaxation approach to harmonic boundary values problems in 1950. [3][4] Humble's Peaceman, Rachford, and Douglas followed soon after with the ADI Alternating Direction Implicit approach. [5] These methods were purely about using a mesh or grid of points to cover a space and calculating differences between the points, based on some given values on the boundary. The value at each mesh point was a variable, so for a 100 x 100 mesh there were 10E4 variables. A full matrix representation of the equations would have 10E8 elements, far too many for the memories or storage of the era, so sparse matrix representations and band matrix structure were essential concepts. Frankel had of course been deeply involved with the IBM CPC precursors at Los Alamos, and the ADI work at Humble was done on a CPC. Young was working at the Aberdeen Proving Ground at the time, a major CPC site, though it seems he was mostly working with the ORDVAC. For these machines, converting the linear algebra into its most minimalistic forms was essential.

At Aberdeen in the early fifites, David Young was working with his first student, Charles Warlick. After reentry vehicle work at TRW, Young moved to UT Austin in 1958 to help found the Computation Center, the same year that Humble donated its IBM CPC to Al Matsen and the chemistry department in Welch Hall. In 1965, Young brought Warlick to UT to head the Computation Center. There's another connection in discussion from Peaceman of the work at Humble in Houston around 1953.

We had access in those days to several eminent consultants. One of them was John von Neumann, and he visited us a couple of times. He was very interested in the work we were doing, but when we asked him how to go about solving two-dimensional problems of this sort, he had no more to offer than the so-called extrapolated Liebman method, now known as successive overrelaxation, or SOR. We already knew about that method. [6]

1944 Los Alamos precursors of the 1949 IBM CPC

[1] Excellent history for Stan Frankel. Be sure to read about his creation of the LGP-30, of Story of Mel fame, about mid way down the page. Also an excellent website for seventies HP computers.

[2] B. J. Archer, "The Los Alamos Computing Facility During the Manhattan Project," Nuclear Technology 207, no. sup1 (2021).

[3] David M. Young Jr., "Iterative Methods for Solving Partial Difference Equations of Elliptic Type" (PhD diss., Harvard University, 1950).

[4] Stanley P. Frankel, "Convergence Rates of Iterative Treatments of Partial Differential Equations," Mathematical Tables and Other Aids to Computation 4, no. 30 (1950): 65–75.

[5] D. W. Peaceman and H. H. Rachford Jr., "The Numerical Solution of Parabolic and Elliptic Differential Equations," Journal of the Society for Industrial and Applied Mathematics 3, no. 1 (1955): 28–41.

[6] Peaceman, Donald W. 1990. "A Personal Retrospection of Reservoir Simulation." In A History of Scientific Computing, edited by Stephen G. Nash, 106–29. New York: ACM Press / Addison-Wesley.

Earlier posts on related topics

https://decwarorg.blogspot.com/2026/05/oldest-computer-on-campus-but-not-first.html 

https://decwarorg.blogspot.com/2026/06/cdc-at-ut-austin-and-ibm-at-exxon.html 

https://decwarorg.blogspot.com/2026/05/welch-hall-1958-benedict-hall-1960.html 

Friday, October 9, 2026

Replicants as Assistants

When Oscar Vermeulen and Obsolescence Guaranteed released the PiDP-10 in 2024, the first stirrings of decwar.org began immediately. The long range vision was to get Decwar working on the PiDP-10 and create a welcoming experience. Two years later, out of the blue Oscar has suddenly appeared again with another piece of the puzzle. Oscar posted about his new Hermes-based project on the Retro Computing Forum on Tuesday, and by Friday morning it was working with Decwar within a new decwar.org repo downstream from Oscar's repo. The picture at the top of this post is a screenshot from the first few minutes with the Decwar version actively playing the game. Thanks to Oscar's usual excellent work preparing and documenting everything, it took just a few hours to go from zero to:

  • Coach: you operate the game; Hermes explains the screen and suggests one move at a time.
  • Assist: Hermes recommends moves and waits for your approval before sending each one.
  • Play: ask Hermes to play for you; it can make game moves directly and explain its decisions.

It was a thrilling experience, seeing how smoothly and capably the replicant integrated itself into the interface between human and game, which is of course purely textual with Decwar. This is one of the special things about the game. It's purely text in a telnet session. Nothing more. What was so surprising was how an elegant, and even beautiful, modern text environment, with a replicant assistant guiding everything smoothly along, adds to the spirit of things. A realistic VT52 experience has a unique beauty. So does the other end of the spectrum, with a leading-edge environment and the new types of experiences that become possible.

Could the replicants grow beyond assistants to also bring in things like personalities and ambience from the Southwest Texas State computation center terminal room circa 1984? When decwar.org began evolving back in 2024, that was already very much in mind, and Oscar's work is a solid step in that direction. Right now, a Decwar replicant is a docker container. When it's possible to have everything internal within the container, completely standalone and no external dependencies or costs, the stage will be set. Running ten standalone containers with ten different personalities could become a normal everyday thing. 

Saturday, October 3, 2026

How Decwar Came About and Prospered as Megawars

"You know, we expected Compuserve customers to spend $10 to $15 a month. We never expected people to come online and spend $1200, $2000 a month playing Megawars." Bill Louden [1]

The story of how Decwar came about naturally begins with 1962 and Spacewar, a graphical videogame-style simulation of a battle between two spaceships, made feasible by the PDP-1 and absolutely requiring a graphical display. At the same time, in the fifties and sixties another style of simulation gaming was moving out of think-tanks like RAND and into the hobbyist world. These were generally tabletop games, but significantly they were often also heavily textual, so much so that they could be played via hand written letters and the mail. For mainframe computers without a graphical display, the textual Star Trek games of the early seventies fused the influences of both Spacewar and tabletop simulation gaming. And notably, at first these were definitely mainframe games, created and played at institutions like universities and large companies capable of supporting both expensive hardware and users with serious computer skills. At UT, the first Star Trek games were written on the very expensive 1966 CDC 6600 supercomputer. When UT purchased the more modern and interactive PDP-10 in 1975, Decwar and eighteen timesharing players became technically feasible and, curiously, its end-of-an-era mainframe genes made it much like having up to eighteen players gathered around a tabletop boardgame. If the players turned away from the game board (their terminals), nothing happened in the game. In fact, in the Decwar source code there are forty-six uses of the term board, for game board, compared to thirty-five uses of the term galaxy for the same spatial concepts. 

The Star Trek games and Decwar of course worked hard at creating the speed and excitement of Spacewar-style play, but it was somewhat of an illusion made possible by the speed of the computer, and at heart they were much like turn-based simulations not so different from those created at Avalon Hill or SPI. A slow version of Decwar could in theory be played on a tabletop with a grid game board, counters or game pieces, and dice, or by hand written letters and the mail for that matter. That the real game was so thrilling and addictive is a testament to the blending of both Spacewar’s energy and tabletop simulation gaming’s depth. The sight of Southwest Texas State University’s computation center terminal room in 1984, with Decwar players shoulder-to-shoulder, gazing intently into CRT terminals and poised to spring into action, couldn’t help but bring to mind the strategies and simulations captured in photos of the old SAGE Direction Centers and Combat Centers, which were in turn heavily influenced by the Software Development Corporation division of RAND. All of this was able to spread around the globe by simply mailing a letter and fifty dollars to UT and receiving a magnetic tape back, and that's exactly what Compuserve's Bill Louden did in early 1982.

Reconstruction of the UT Decwar 2.3 Source Distribution Tape is based on a snapshot of a Compuserve KI10 filesystem created around May 19, 1982. It includes the contents of the SDT sent by UT, with minimal modifications and diagnostics to integrate the game into Compuserve’s commercial environment and generate revenue. The calendar date comes from a memory map file that was likely generated as part of creating the snapshot. Compuserve had strong incentives to keep the initial changes minimal, as the extensive MACRO-10 assembly code is unforgiving to work with. Decwars, with an “s”, was first advertised in the Compuserve magazine in April 1982. By September 1982, it had become Megawars. The Compuserve KI10 was likely an older machine used for development and matching with the KI10 at UT, as Compuserve’s main customer-facing machine for multi-player gaming is believed to have been a newer dual KL10, and customers from across the country were routed to the KL within Compuserve’s internal network. [2][3]

SAGE Direction Center running software from the Software Development Corporation division of RAND.
Southwest Texas State University's computation center in San Marcos Texas, viewed from the north. The DEC-10 machine room was in the south-west corner, and the terminal room was in the core of the right-hand side of the building. The SWT and UT DEC-10s were in some sense siblings seperated by thirty miles of open countryside, at least back in the day.

The UT KI10 where Decwar was created, on the evening of The Soul of an Old Machine. [4]

[1] Interview with Compuserve's Bill Louden.

[2] Historical evidence of Compuserve's early work with the source code.

[3] April 1982 issue of Compuserve's Today magazine with a Decwar launch article. September 1982 issue with a Megawars launch article.

[4] The Soul of an Old Machine.

Saturday, September 19, 2026

Bruce Sterling's 1993 Short History of the Internet

Here's a relaxing trip back to 1993. Even better, Austin Texas in 1993. Bruce doesn't mention it here, but he was in at least his third decade as an Austinite at the time. He had published The Hacker Crackdown in 1992 and it has some discussion of his own experiences with computers and networks. This article undoubtedly grew along with and out of the book.

Had forgotten this since reading it thirty-three years ago and rediscovered it this morning. Similar to The Hacker Crackdown, Bruce published it as freeware. When you've enjoyed this pure pleasure, ordering a copy of both The Hacker Crackdown and Schismatrix seems like a good way to say thanks.

Enjoy!

Short History of the Internet

From THE MAGAZINE OF FANTASY AND SCIENCE FICTION, February 1993  
Written by Bruce Sterling  
Literary Freeware – Not for Commercial Use
F&SF Science Column #5 “Internet”

Some thirty years ago, the RAND Corporation, America’s foremost Cold War think-tank, faced a strange strategic problem. How could the US authorities successfully communicate after a nuclear war?

Postnuclear America would need a command-and-control network, linked from city to city, state to state, base to base. But no matter how thoroughly that network was armored or protected, its switches and wiring would always be vulnerable to the impact of atomic bombs. A nuclear attack would reduce any conceivable network to tatters.

And how would the network itself be commanded and controlled? Any central authority, any network central citadel, would be an obvious and immediate target for an enemy missile. The center of the network would be the very first place to go. RAND mulled over this grim puzzle in deep military secrecy, and arrived at a daring solution. The RAND proposal (the brainchild of RAND staffer Paul Baran) was made public in 1964. In the first place, the network would have no central authority. Furthermore, it would be designed from the beginning to operate while in tatters.

The principles were simple. The network itself would be assumed to be unreliable at all times. It would be designed from the get-go to transcend its own unreliability. All the nodes in the network would be equal in status to all other nodes, each node with its own authority to originate, pass, and receive messages. The messages themselves would be divided into packets, each packet separately addressed. Each packet would begin at some specified source node, and end at some other specified destination node. Each packet would wind its way through the network on an individual basis.

The particular route that the packet took would be unimportant. Only final results would count. Basically, the packet would be tossed like a hot potato from node to node to node, more or less in the direction of its destination, until it ended up in the proper place. If big pieces of the network had been blown away, that simply wouldn’t matter; the packets would still stay airborne, lateralled wildly across the field by whatever nodes happened to survive. This rather haphazard delivery system might be “inefficient” in the usual sense (especially compared to, say, the telephone system) — but it would be extremely rugged.

During the 60s, this intriguing concept of a decentralized, blastproof, packet-switching network was kicked around by RAND, MIT and UCLA. The National Physical Laboratory in Great Britain set up the first test network on these principles in 1968. Shortly afterward, the Pentagon’s Advanced Research Projects Agency decided to fund a larger, more ambitious project in the USA. The nodes of the network were to be high-speed supercomputers (or what passed for supercomputers at the time). These were rare and valuable machines which were in real need of good solid networking, for the sake of national research-and-development projects.

In fall 1969, the first such node was installed in UCLA. By December 1969, there were four nodes on the infant network, which was named ARPANET, after its Pentagon sponsor. The four computers could transfer data on dedicated high-speed transmission lines. They could even be programmed remotely from the other nodes. Thanks to ARPANET, scientists and researchers could share one another’s computer facilities by long-distance. This was a very handy service, for computer-time was precious in the early ’70s. In 1971 there were fifteen nodes in ARPANET; by 1972, thirty-seven nodes. And it was good.

By the second year of operation, however, an odd fact became clear. ARPANET’s users had warped the computer-sharing network into a dedicated, high-speed, federally subsidized electronic post- office. The main traffic on ARPANET was not long-distance computing. Instead, it was news and personal messages. Researchers were using ARPANET to collaborate on projects, to trade notes on work, and eventually, to downright gossip and schmooze. People had their own personal user accounts on the ARPANET computers, and their own personal addresses for electronic mail. Not only were they using ARPANET for person-to-person communication, but they were very enthusiastic about this particular service — far more enthusiastic than they were about long-distance computation.

It wasn’t long before the invention of the mailing-list, an ARPANET broadcasting technique in which an identical message could be sent automatically to large numbers of network subscribers. Interestingly, one of the first really big mailing-lists was “SF-LOVERS,” for science fiction fans. Discussing science fiction on the network was not work-related and was frowned upon by many ARPANET computer administrators, but this didn’t stop it from happening.

Throughout the ’70s, ARPA’s network grew. Its decentralized structure made expansion easy. Unlike standard corporate computer networks, the ARPA network could accommodate many different kinds of machine. As long as individual machines could speak the packet-switching lingua franca of the new, anarchic network, their brand-names, and their content, and even their ownership, were irrelevant.

The ARPA’s original standard for communication was known as NCP, “Network Control Protocol,” but as time passed and the technique advanced, NCP was superceded by a higher-level, more sophisticated standard known as TCP/IP. TCP, or “Transmission Control Protocol,” converts messages into streams of packets at the source, then reassembles them back into messages at the destination. IP, or “Internet Protocol,” handles the addressing, seeing to it that packets are routed across multiple nodes and even across multiple networks with multiple standards — not only ARPA’s pioneering NCP standard, but others like Ethernet, FDDI, and X.25.

As early as 1977, TCP/IP was being used by other networks to link to ARPANET. ARPANET itself remained fairly tightly controlled, at least until 1983, when its military segment broke off and became MILNET. But TCP/IP linked them all. And ARPANET itself, though it was growing, became a smaller and smaller neighborhood amid the vastly growing galaxy of other linked machines.

As the ’70s and ’80s advanced, many very different social groups found themselves in possession of powerful computers. It was fairly easy to link these computers to the growing network-of- networks. As the use of TCP/IP became more common, entire other networks fell into the digital embrace of the Internet, and messily adhered. Since the software called TCP/IP was public-domain, and the basic technology was decentralized and rather anarchic by its very nature, it was difficult to stop people from barging in and linking up somewhere-or-other. In point of fact, nobody wanted to stop them from joining this branching complex of networks, which came to be known as the “Internet.”

Connecting to the Internet cost the taxpayer little or nothing, since each node was independent, and had to handle its own financing and its own technical requirements. The more, the merrier. Like the phone network, the computer network became steadily more valuable as it embraced larger and larger territories of people and resources. A fax machine is only valuable if everybody else has a fax machine. Until they do, a fax machine is just a curiosity. ARPANET, too, was a curiosity for a while. Then computer-networking became an utter necessity.

In 1984 the National Science Foundation got into the act, through its Office of Advanced Scientific Computing. The new NSFNET set a blistering pace for technical advancement, linking newer, faster, shinier supercomputers, through thicker, faster links, upgraded and expanded, again and again, in 1986, 1988, 1990. And other government agencies leapt in: NASA, the National Institutes of Health, the Department of Energy, each of them maintaining a digital satrapy in the Internet confederation.

The nodes in this growing network-of-networks were divvied up into basic varieties. Foreign computers, and a few American ones, chose to be denoted by their geographical locations. The others were grouped by the six basic Internet “domains”: gov, mil, edu, com, org and net. (Graceless abbreviations such as this are a standard feature of the TCP/IP protocols.) Gov, Mil, and Edu denoted governmental, military and educational institutions, which were, of course, the pioneers, since ARPANET had begun as a high-tech research exercise in national security. Com, however, stood for “commercial” institutions, which were soon bursting into the network like rodeo bulls, surrounded by a dust-cloud of eager nonprofit “orgs.” (The “net” computers served as gateways between networks.)

ARPANET itself formally expired in 1989, a happy victim of its own overwhelming success. Its users scarcely noticed, for ARPANET’s functions not only continued but steadily improved. The use of TCP/IP standards for computer networking is now global. In 1971, a mere twenty-one years ago, there were only four nodes in the ARPANET network. Today there are tens of thousands of nodes in the Internet, scattered over forty-two countries, with more coming on-line every day. Three million, possibly four million people use this gigantic mother-of-all-computer-networks.

The Internet is especially popular among scientists, and is probably the most important scientific instrument of the late twentieth century. The powerful, sophisticated access that it provides to specialized data and personal communication has sped up the pace of scientific research enormously. The Internet’s pace of growth in the early 1990s is spectacular, almost ferocious. It is spreading faster than cellular phones, faster than fax machines. Last year the Internet was growing at a rate of twenty percent a month. The number of “host” machines with direct connection to TCP/IP has been doubling every year since 1988. The Internet is moving out of its original base in military and research institutions, into elementary and high schools, as well as into public libraries and the commercial sector.

Why do people want to be “on the Internet?” One of the main reasons is simple freedom. The Internet is a rare example of a true, modern, functional anarchy. There is no “Internet Inc.” There are no official censors, no bosses, no board of directors, no stockholders. In principle, any node can speak as a peer to any other node, as long as it obeys the rules of the TCP/IP protocols, which are strictly technical, not social or political. (There has been some struggle over commercial use of the Internet, but that situation is changing as businesses supply their own links).

The Internet is also a bargain. The Internet as a whole, unlike the phone system, doesn’t charge for long-distance service. And unlike most commercial computer networks, it doesn’t charge for access time, either. In fact the “Internet” itself, which doesn’t even officially exist as an entity, never “charges” for anything. Each group of people accessing the Internet is responsible for their own machine and their own section of line.

The Internet’s “anarchy” may seem strange or even unnatural, but it makes a certain deep and basic sense. It’s rather like the “anarchy” of the English language. Nobody rents English, and nobody owns English. As an English-speaking person, it’s up to you to learn how to speak English properly and make whatever use you please of it (though the government provides certain subsidies to help you learn to read and write a bit). Otherwise, everybody just sort of pitches in, and somehow the thing evolves on its own, and somehow turns out workable. And interesting. Fascinating, even. Though a lot of people earn their living from using and exploiting and teaching English, “English” as an institution is public property, a public good. Much the same goes for the Internet. Would English be improved if the “The English Language, Inc.” had a board of directors and a chief executive officer, or a President and a Congress? There’d probably be a lot fewer new words in English, and a lot fewer new ideas. People on the Internet feel much the same way about their own institution. It’s an institution that resists institutionalization. The Internet belongs to everyone and no one.

Still, its various interest groups all have a claim. Business people want the Internet put on a sounder financial footing. Government people want the Internet more fully regulated. Academics want it dedicated exclusively to scholarly research. Military people want it spy-proof and secure. And so on and so on. All these sources of conflict remain in a stumbling balance today, and the Internet, so far, remains in a thrivingly anarchical condition. Once upon a time, the NSFnet’s high-speed, high-capacity lines were known as the “Internet Backbone,” and their owners could rather lord it over the rest of the Internet; but today there are “backbones” in Canada, Japan, and Europe, and even privately owned commercial Internet backbones specially created for carrying business traffic. Today, even privately owned desktop computers can become Internet nodes. You can carry one under your arm. Soon, perhaps, on your wrist.

But what does one do with the Internet? Four things, basically: mail, discussion groups, long-distance computing, and file transfers.

Internet mail is “e-mail,” electronic mail, faster by several orders of magnitude than the US Mail, which is scornfully known by Internet regulars as “snailmail.” Internet mail is somewhat like fax. It’s electronic text. But you don’t have to pay for it (at least not directly), and it’s global in scope. E-mail can also send software and certain forms of compressed digital imagery. New forms of mail are in the works.

The discussion groups, or “newsgroups,” are a world of their own. This world of news, debate and argument is generally known as “USENET. ” USENET is, in point of fact, quite different from the Internet. USENET is rather like an enormous billowing crowd of gossipy, news-hungry people, wandering in and through the Internet on their way to various private backyard barbecues. USENET is not so much a physical network as a set of social conventions. In any case, at the moment there are some 2,500 separate newsgroups on USENET, and their discussions generate about 7 million words of typed commentary every single day. Naturally there is a vast amount of talk about computers on USENET, but the variety of subjects discussed is enormous, and it’s growing larger all the time. USENET also distributes various free electronic journals and publications.

Both netnews and e-mail are very widely available, even outside the high-speed core of the Internet itself. News and e-mail are easily available over common phone-lines, from Internet fringe- realms like BITnet, UUCP and Fidonet. The last two Internet services, long-distance computing and file transfer, require what is known as “direct Internet access” — using TCP/IP.

Long-distance computing was an original inspiration for ARPANET and is still a very useful service, at least for some. Programmers can maintain accounts on distant, powerful computers, run programs there or write their own. Scientists can make use of powerful supercomputers a continent away. Libraries offer their electronic card catalogs for free search. Enormous CD-ROM catalogs are increasingly available through this service. And there are fantastic amounts of free software available.

File transfers allow Internet users to access remote machines and retrieve programs or text. Many Internet computers — some two thousand of them, so far — allow any person to access them anonymously, and to simply copy their public files, free of charge. This is no small deal, since entire books can be transferred through direct Internet access in a matter of minutes. Today, in 1992, there are over a million such public files available to anyone who asks for them (and many more millions of files are available to people with accounts). Internet file-transfers are becoming a new form of publishing, in which the reader simply electronically copies the work on demand, in any quantity he or she wants, for free. New Internet programs, such as “archie,” “gopher,” and “WAIS,” have been developed to catalog and explore these enormous archives of material.

The headless, anarchic, million-limbed Internet is spreading like bread-mold. Any computer of sufficient power is a potential spore for the Internet, and today such computers sell for less than $2,000 and are in the hands of people all over the world. ARPA’s network, designed to assure control of a ravaged society after a nuclear holocaust, has been superceded by its mutant child the Internet, which is thoroughly out of control, and spreading exponentially through the post-Cold War electronic global village. The spread of the Internet in the 90s resembles the spread of personal computing in the 1970s, though it is even faster and perhaps more important. More important, perhaps, because it may give those personal computers a means of cheap, easy storage and access that is truly planetary in scale.

The future of the Internet bids fair to be bigger and exponentially faster. Commercialization of the Internet is a very hot topic today, with every manner of wild new commercial information- service promised. The federal government, pleased with an unsought success, is also still very much in the act. NREN, the National Research and Education Network, was approved by the US Congress in fall 1991, as a five-year, $2 billion project to upgrade the Internet “backbone.” NREN will be some fifty times faster than the fastest network available today, allowing the electronic transfer of the entire Encyclopedia Britannica in one hot second. Computer networks worldwide will feature 3-D animated graphics, radio and cellular phone-links to portable computers, as well as fax, voice, and high- definition television. A multimedia global circus!

Or so it’s hoped — and planned. The real Internet of the future may bear very little resemblance to today’s plans. Planning has never seemed to have much to do with the seething, fungal development of the Internet. After all, today’s Internet bears little resemblance to those original grim plans for RAND’s post- holocaust command grid. It’s a fine and happy irony.

How does one get access to the Internet? Well — if you don’t have a computer and a modem, get one. Your computer can act as a terminal, and you can use an ordinary telephone line to connect to an Internet-linked machine. These slower and simpler adjuncts to the Internet can provide you with the netnews discussion groups and your own e-mail address. These are services worth having — though if you only have mail and news, you’re not actually “on the Internet” proper.

If you’re on a campus, your university may have direct “dedicated access” to high-speed Internet TCP/IP lines. Apply for an Internet account on a dedicated campus machine, and you may be able to get those hot-dog long-distance computing and file-transfer functions. Some cities, such as Cleveland, supply “freenet” community access. Businesses increasingly have Internet access, and are willing to sell it to subscribers. The standard fee is about $40 a month — about the same as TV cable service.

As the Nineties proceed, finding a link to the Internet will become much cheaper and easier. Its ease of use will also improve, which is fine news, for the savage UNIX interface of TCP/IP leaves plenty of room for advancements in user-friendliness. Learning the Internet now, or at least learning about it, is wise. By the turn of the century, “network literacy,” like “computer literacy” before it, will be forcing itself into the very texture of your life.

For Further Reading:

The Whole Internet Catalog & User’s Guide by Ed Krol. (1992) O’Reilly and Associates, Inc. A clear, non-jargonized introduction to the intimidating business of network literacy. Many computer- documentation manuals attempt to be funny. Mr. Krol’s book is actually funny.

The Matrix: Computer Networks and Conferencing Systems Worldwide. by John Quarterman. Digital Press: Bedford, MA. (1990) Massive and highly technical compendium detailing the mind-boggling scope and complexity of our newly networked planet.

The Internet Companion by Tracy LaQuey with Jeanne C. Ryer (1992) Addison Wesley. Evangelical etiquette guide to the Internet featuring anecdotal tales of life-changing Internet experiences. Foreword by Senator Al Gore.

Zen and the Art of the Internet: A Beginner’s Guide by Brendan P. Kehoe (1992) Prentice Hall. Brief but useful Internet guide with plenty of good advice on useful machines to paw over for data. Mr Kehoe’s guide bears the singularly wonderful distinction of being available in electronic form free of charge.

I’m doing the same with all my F&SF Science articles, including, of course, this one.

Saturday, September 12, 2026

Texas Minor Planet Project and Hubble Space Telescope Astrometry

The story of laser ranging at McDonald Observatory and its role in operational satellite tracking at UT can be traced back to Harlan Smith, a pioneering administrator who foresaw the critical role that ground-based observatories would play in supporting space exploration. He successfully convinced NASA, the National Science Foundation, and UT Austin to jointly fund the 107-inch telescope at McDonald Observatory in the sixties. This telescope became the primary ground-based facility for the pioneering lunar laser ranging experiments and was classed as a component in the overall Apollo program. He also served on major national committees, including the National Academy of Sciences committee that helped lay the groundwork for the Hubble Space Telescope.

Hubble was good example of how McDonald integrated into the space age, particularly the structural role McDonald played in Hubble astrometry and the parallels with McDonald’s role in geodesy. Both astrometry and geodesy are concerned with fundamental reference measurements, of the celestial and terrestrial realms respectively. For Hubble, McDonald provided precise ground-based tracking data for calibrating the spacecraft's instruments via a direct integration between the Texas Minor Planet Program and the Hubble astrometry team. The primary astrometric instruments aboard Hubble were the fine guidance sensors. To achieve sub-millisecond of arc precision, the astrometry team had to map and correct severe optical field angle distortions caused by the telescope's mirrors and refractive optics. While static distortions were mapped by observing distant, fixed star clusters like M35, the team also needed to perform dynamic calibrations, such as tracking time-varying mechanical flexures, scale changes, and the alignment between the three independent fine guidance units. To do this, they needed to track moving celestial targets with highly predictable paths. Minor planets, or asteroids, were selected as the ideal moving targets. [1]

For the fine guidance calibration to work, the orbital paths of these minor planets had to be known to a higher degree of accuracy than the guidance sensor measurement precision itself. To achieve this, Paul Hemenway and Raynor Duncombe initiated the Texas Minor Planet Program in 1978. The intro photo of this post shows Paul on the left and Ray on the right. Between, left to right, are Bill Jefferys, Fritz Benedict, and Pete Shelus.

Using the long-focus Cassegrain focal plane of the 82-inch telescope at McDonald, the team targeted thirty-four specific minor planets, twenty of which were suited for HST observation. Over the course of the project, researchers captured more than a thousand glass photographic plates of these asteroids. An innovation of the program was the crossing-point method. By taking observations exactly where the projected paths of two different minor planets intersected, researchers could compare the objects against the same local background stars at different times, effectively isolating and eliminating systematic star catalog errors from their orbit reductions.

The precise ground-based observations from McDonald were processed by orbit determination specialists at UT Austin's Center for Space Research. By feeding the McDonald data into complex dynamical models, the team refined the asteroid orbits so that their orbital uncertainty was reduced to near-zero. Because these ground-truth reference trajectories were so precise, any deviations or residuals recorded by the fine guidance sensors could be attributed directly to their own instrumental distortions rather than the asteroid's actual motion.

This integration of McDonald Observatory's minor planet data and Hubble astrometry was used to resolve broader issues in celestial mechanics. The combined data allowed researchers to measure the unknown rotation of the European Hipparcos satellite's instrumental coordinate system, effectively linking the stellar optical reference system to a dynamical, gravity-based reference frame. These results were directly incorporated into the celestial reference frame, much as the McDonald geodetic measurements were incorporated in the terrestrial reference frame. Both of these research fields, astrometry and geodesy, can be traced directly to the inspiration from Harlan Smith to focus on participating as fully as possible in NASA’s space missions, tying McDonald and the West Texas Chihuahuan Desert together with the realm of satellites and spacecraft.

Harlan Smith and Ray Duncombe. Many count themselves fortunate to have known Harlan and Ray.
The 82-inch telescope at McDonald, where glass-plate photographs of asteroids were made on many a Chihuahuan Desert night.
Operator's console on the observer's deck.
[1] HST Astrometry Team 

Refinery Modeling and Simplex

The growth of computing for optimizing refinery operations was rapid. In Houston, John Bonner and Joe Moore were chemical engineers at Humbl...