Soviet Satellites and Mapping

John Davies’ website has announced that his and Alexander Kent’s book The Red Atlas: How the Soviet Union Secretly Mapped the World will be released by University of Chicago Press. Details for the book on the press website show 272 pages and 282 (!) colour plates and a publication month of October 2017. Having read what the authors have written elsewhere about Soviet maps, I’m really looking forward to the book. In particular, I’m hoping it will offer not just more information on how the Soviet military prepared their maps but also some insight into why and for who.

The technical military challenges that drove both American and Soviet cartographic projects during the Cold War were very similar, which leaves the differences in practice between them begging for explanation. Take, for example, the apparent difference in exploiting satellite geodesy. Both countries very swiftly exploited the fact that perturbations in satellite orbits revealed new details on gravity and, by extension, the shape of the earth. They also must have recognized that satellites made better targets for intercontinental triangulation than rockets, stars, or the sun and moon, all conventional targets at the time.

As a result, Sputnik effectively sidelined an American-led terrestrial program of geodetic measurements for the International Geophysical Year that had been under development since 1954. Led by William Markowitz of the US Naval Observatory, using dual-rate cameras of his own design, the program distributed cameras to observatories around the world to make simultaneous moon observations during 1957. Using an approach to triangulation similar to that used during eclipses, the promised precision was to within about 90 feet at each observatory. Uncertainties in the position of the moon meant the 1957 observations never delivered geodetic results, but more substantially the entire concept had been rendered obsolete.

Consequently, in addition to measurement projects that were added to other scientific satellites, the US launched its first dedicated geodetic satellite in 1962. ANNA-1B was a joint Department of Defense-NASA project that carried instruments to enable both triangulation and trilateration. Its launch came only two years after the US lofted its first photo-reconnaissance satellite, which makes sense because both satellites were part of the effort to find and target Soviet strategic missiles.

Intriguingly, then, it was six more years before the Soviet Union launched its own dedicated geodetic satellite. The first of the Sfera series (Russian for “Geoid”) satellites (11F621) flew in 1968, launched from the rocket base at Pleketsk. Built by design bureau OKB-10 on the popular KAUR satellite bus, the Sfera satellites were equipped with lights and radio transmitters similar to those on ANNA-1B. Operational flights ran from 1973 to 1980.

A similar difference was apparent in the case of satellites equipped with cameras for mapping, as opposed to high-resolution reconnaissance photography. A dedicated mapping satellite was among the planned elements of the first US reconnaissance satellite system, the Air Force’s SAMOS (or Satellite and Missile Observation System). That camera, the E-4, never flew, but the Army’s very similar project ARGON was grafted onto the CIA Corona program. ARGON was rendered obsolete by the inclusion of small mapping cameras on subsequent satellite systems but after ARGON’s first launch in 1961 – only one year after the very first US reconnaissance satellite – the US was never without a mapping capacity in orbit.

In the USSR, on the other hand, the first dedicated mapping satellite came quite late. The Zenit-4MT, program name Orion (11F629), was a variant of the main Soviet series of photo-reconnaissance satellites. First launched in 1971 and accepted into operational service in 1976, Orion began flying nine years after the first Soviet photo-reconnaissance satellite was launched. Unlike the Americans, who integrated mapping cameras into other photo-reconnaissance satellites, the Soviets seem to have continued to fly dedicated cartographic systems for the remainder of the Cold War (this is early 2000s information, so it may be obsolete now). Zenit-4MT (Orion) was followed in the early 1980s by the Yantar-1KFT, program name Siluet/Kometa (11F660), a system which combined the propulsion and instrument modules of the latest Soviet photo-reconnaissance satellite with the descent canister from the Zenit-4MT. Flying alongside Kometa was an upgraded Zenit, the Zenit-8, program name Oblik, an interim design introduced because of delays in the former.

I hope The Red Atlas or someone else can explain more about what was happening here, because it certainly looks like the Soviet Union was making very different decisions from the Americans when it came to satellite geodesy and cartography.

Source Notes: Information on Soviet satellites comes from a range of sources, much of it in the Journal of the British Interplanetary Society. For the Orion series, Philip S. Clark, “Orion: The First Soviet Cartographic Satellites,” JBIS vol. 54 (2001), pp. 417–23. For Siluet/Kometa, Philip S. Clark, “Classes of Soviet/Russian Photoreconnaissance Satellites,”JBIS vol. 54 (2001), pp. 344–650. On the launch of Sfera from Pleketsk, Bart Hendrickx,”Building a Rocket Base in the Taiga: The Early Years of the Plesetsk Launch Site (1955-1969) (Part 2),” JBIS vol. 66, Supplement 2 (2013), pp. 220 (and online). For the Markowitz moon camera, Steven J.  Dick, “Geodesy, Time, and the Markowitz Moon Camera Program: An Interwoven International Geophysical Year Story,” in Globalizing Polar Science: Reconsidering the International Polar and Geophysical Years, edited by Roger D. Launius, James Roger Fleming, and David H. DeVorkin (Palgrave Macmillan, 2010).
Advertisements

Hidden Figures

The release of two widely publicized books on female computers in the early Space Age in the same year (one of them with a forthcoming movie adaptation too) has to be unprecedented. The first was Rise of the Rocket Girls, about the women who worked as human computers (a redundant term before the 1950s) for the Jet Propulsion Laboratory in Pasadena, California. The second, Hidden Figures, is about the African-American women among those who did similar work for the Langley research center in Virginia. (There’s even a third book, by Dava Sobel, that covers an earlier generation of computers who worked at the Harvard Observatory).

Both Rise of the Rocket Girls and Hidden Figures are fascinating accounts of the essential roles that female computers played in aerospace research, capturing the challenging social milieu in which they worked. Hidden Figures also manages to address the impact of segregation and discrimination in the overlapping local, regional, and national contexts surrounding the work of the computers at Langley (itself a segregated workplace). It’s a story well worth reading, before or after the movie adaptation – focusing on Katherine Johnson’s contribution to the calculations for the first orbital Mercury flight – goes into wide release in January. The trailers I’ve seen look good, though Kevin Costner as a fictional NASA manager gets to strike a literal blow (with a fire axe!) against racism that goes way beyond anything NASA management actually did for their African-American staff.

In the last chapter of Hidden Figures, Shetterly discusses having to cut the section of the book about how several of its key figures moved into human resources and advocacy to try and overcome the less obvious discrimination against women and minorities in the workforce that was still going on in the 1970s and 80s. You never know from a trailer, but I suspect the movie’s not going to end with the uphill battle for recognition and equal treatment that persisted even after Johnson’s work.

As Sobel’s made clear in some of her pre-publication publicity, the stories of female computers are less undiscovered than regularly and distressingly forgotten. The women who worked in the Harvard Observatory were well known at the time; Katherine Johnson received substantial publicity at least within the African-American press for her work on Mercury. Academic writing, including a book with Princeton University Press, has covered the work of female computers in various fora. Perhaps a major Hollywood movie will help the story stick this time.

The Last of the Computers

One of the first hires at the Jet Propulsion Laboratory (JPL) in Pasadena, before JPL became a NASA facility and even before it had the name JPL, was Barbara Canright. Canright was employed as a “computer” who would do complicated and repetitive mathematics for JPL’s engineers, as were many women who followed in her footsteps at JPL.

From the nineteenth century until the 1960s, many large-scale scientific and engineering project relied on human computers – often female university graduates without the same employment opportunities as their male counterparts – to handle the computational load. As Nathalia Holt explains in her recent book Rise of the Rocket Girls, JPL was no different. Holt’s book describes the careers of computers at JPL from the 1940s to the present: one of the last computers to be hired, Susan Finley, still works at the laboratory.

The book does an excellent job narrating the personal trials and professional triumphs of these women, including the disappearance of computing by hand. By the time JPL acquired its name in 1943, multi-purpose electronic computers were only a matter of years away. In the 1950s, JPL’s computing department acquired the first of many IBM mainframes to do calculation work. “Cora” (for Core Storage) was given a woman’s name to fit into the all-female group. Many of the women who worked with it soon branched out into programming in FORTRAN and other languages, at a time when programming had little or none of the prestige which it would later acquire. That decision helped them carve out a niche which survived when hand calculation was eliminated as a trade by the electronic computers, leading to the computer department being renamed Mission Design and the women who had worked there eventually retitled as engineers. Rise of the Rocket Girls describes their ongoing contributions to a list of JPL space probes that includes Ranger, Mariner, Viking, and Voyager.

It’s an interesting story not least because the female calculators employed at JPL were among the last in the business. Their success in transitioning into the Computer Age, reflected both in their success as individuals and in the establishment of Mission Design, was loaded with assumptions about how the aerospace industry valued various kinds of work. Though Holt doesn’t linger on them, in a lot of ways the undercurrents in Rise of the Rocket Girls reminded me of Rebecca Slayton’s Arguments that Count, which examined the relative influence of physicists and computer scientists in planning for ballistic missile defense during the same era.

 

Spacesuit Style

Gizmodo is reporting that SpaceX has hired costume designer Jose Fernandez, whose work appears in Batman v Superman, Tron: Legacy, The Avengers, Iron Man, and other movies, to design the spacesuits to be used in non-NASA launches aboard the company’s Dragon capsule.

It might be better to say that Fernandez will be styling the suits, since spacesuit design is a pretty technical area. Reportedly, the plan is to begin with a concept design and then engineer it to work from there. It’s a logical move from a company that’s shown a demonstrable love for science fiction (naming its landing barges after spaceships from Ian M. Banks’s Culture novels) and flair for good PR.

SpaceX’s suits will probably go into service along side those used by NASA, who have always been aware of the need for space suit style. As Nicholas de Monchaux explains in his fabulous book Fashioning Apollo, NASA sexed-up its earliest pressure suits – which were essential US Navy pilot’s gear – by adding a layer of silver to make them seem more futuristic. More recently, its experimental Z-series suits have revealed their own touches of fashion. The Z-1, for example, is often nicknamed the “Buzz Lightyear Suit” because of its green striping. For the Z-2, introduced a few years later, NASA commissioned students three different designs from Philadelphia University fashion students and offered the public the change to vote for their favourite: the winner? The Tron-esque “Technology” option.

NASA’s engineers are aware of the demand for cool, Science-Fictional suits, and appreciative of the chance to make some aesthetic tweaks to what’s otherwise a practical design. Talking to io9 last year, suit designer Amy Ross explained:

We’re engineers, and this is space hardware. So a game I used to play with my mentor is “Why is this feature on the suit?” Because this is a very highly engineered product. If there’s a feature there, it’s there for a reason, not just because it looks cool. As fun as that would be, we don’t get that luxury very often.

So with Z1 and Z2, we’ve been given that freedom to think a little bit about what it looks like, and it’s been a lot of fun because spacesuits are cool. We all grew up with these movies too. Hollywood has some really neat things going on and with commercial space coming up, everybody wants to look cool as an astronaut. We don’t usually get to do that but with Z1 and Z2 we really had the opportunity to think a little more about what it’s going to look like.

Both the Z-1 and Z-2 look a lot bulkier than preliminary images of the SpaceX suit I’ve seen because what SpaceX is creating is only a “pressure suit,” designed to be worn inside the pressurized capsule, not a “space suit” that will be exposed to the rigors of extravehicular activity or a moon- or mars-walk. In fact, though suits like the A7L used on Apollo were custom-designed masterpieces, the pressure suits used by Space Shuttle crews over the subsequent thirty years were quick conversions of existing suits.

Until the Challenger disaster in 1986, Shuttle crews flew without pressure suits at all. The Launch Entry Suit that was issued after the accident was a modified version of a existing design by the David Clark Company used by NASA’s Dryden Research Center, combined with a nonconformal helmet that had been tested by the US Air Force for U-2 pilots. When the Air Force introduced a new pressure suit for test pilots, NASA adopted that as its Advanced Crew Escape Suit (details of both can be found in a NASA-sponsored history of US pressure suits, Dressing for Altitude).

Given that one of the early instructions was to look “badass,” we can assume that SpaceX will adopt something sleeker, more form-fitting, and a lot cooler looking. It’ll be interesting to see exactly what they choose.

Aerospace History on the Web

In a very exciting move, Aviation Week and Space Technology has put its entire magazine archive from 1916 to 2016 online (h/t the latest NASA history newsletter). It’s free for now, courtesy of Boeing, although you do have to register. The interface is pretty slick, considerably more so than Flight magazine’s archive, but unlike Flight none of the pages can be downloaded and the content doesn’t come with an encouragement to “link to, copy and paste from, and contribute to the development of this unique record of aerospace and aviation history.” Still, it’s a very cool resource while it lasts.

In the meantime, the Stuff You Missed in History Class podcast has a nice two-part interview about the Women Airforce Service Pilots during the Second World War.

The Space Review has a review of Rise of the Rocket Girls, which looks like a fascinating book about the women who worked as human “computers,” doing repetitive calculations for NASA in its early years. The story of computers,” one of very few opportunities for women with educations in mathematics at the time isn’t a new one: David Alan Grier’s When Computers Were Human is about a decade old, but this looks like a valuable addition to the story. It looks like we’re also going to get both a book, Hidden Figures, and a movie about the first African-American women who worked as NASA computers.

TERCOM, System and Symbol: Part One

On the opening night of the first Gulf War in 1991, seven B-52 bombers flew 14,000 miles from Barksdale Air Force base in Louisiana to launch the first attack in history with GPS-guided weapons. The bombers, whose operation was formally code-named SENIOR SURPRISE but quickly nicknamed “Secret Squirrel,” launched thirty-five Conventional Air-Launched Cruise Missiles (CALCM), each equipped with a single-channel GPS receiver. That made the CALCM was the first and only GPS-guided weapon fired during Operation Desert Storm, though GPS navigation was used by many attack aircraft.

SENIOR SURPRISE was, it turns out, the first step towards a era of cheap and easy GPS-guided weapons. But during Operation Desert Storm those thirty-five missiles fired were vastly outnumbered by their close cousin, the US Navy’s BGM-109 Tomahawk cruise missile. The two missiles shared a common engine, the Williams F107 turbofan, and they had been designed with a common guidance system in mind too. The CALCM’s were a variant of the US Air Force’s nuclear cruise missile: the nuclear version was designated AGM-86A, and it and the BGM-109 shared a guidance system built around Terrain Contour Matching, or TERCOM.

US Navy photo of a Block IV "Tactical Tomahawk" in flight. 021110-N-0000X-003 China Lake, Calif. Courtesy Wikipedia.

US Navy photo of a Block IV “Tactical Tomahawk” in flight. 021110-N-0000X-003 China Lake, Calif. Courtesy Wikipedia.

Today, we think of the first Gulf War as GPS’s coming-out party – which it was – but imagine it as the backbone of the many new weapons the US unleashed during the war – which it wasn’t. That begs the question, what actually was guiding US weapons during the first Gulf War, and why those systems never captured the imagination – for better or worse. After all, in 1992 two activists took axes to unlaunched GPS satellites because GPS was “military in its origins, military in its goals, [and] military in its development.”

TERCOM was the guidance system at the heart of the US cruise missile triad: an air-launched missile that extended the range and capabilities of the US bomber fleet (the ALCM); a submarine and ship-launched missile that gave US Navy ships a strategic nuclear weapon (the Tomahawk); and a ground-launched missile to be based in Europe as a counterpart to the Soviet intermediate-range nuclear arsenal (the Gryphon). Of the three, Tomahawk would have the most significant career. While the ground-launched Gryphon was fairly swiftly traded away in exchange for the Soviets demobilizing their intermediate-range missiles through the INF Treaty, the Tomahawk became the American military’s go-to weapon for punitive strikes during the 1990s. Tomahawks were fired against Iraqi military targets in 1993 and at Afghan and Sudanese targets in response to the East African embassy bombings in 1998, as well as used in conjunction with airstrikes in Bosnia (1995), Iraq (1998), and Serbia (1999). They remain, as journalist Mark Thompson put it in TIME magazine last year, “the curtain-raiser on U.S. military strikes since 1991’s Gulf War.”

(Since the Block III version was introduced in 1993, Tomahawk missiles without nuclear warheads have had GPS guidance in addition to the TERCOM system. The nuclear-armed version remains TERCOM only.)

How TERCOM Worked

Tomahawk flight diagram. From GAO/NSIAD-95-116 (1995), p. 17

Tomahawk flight diagram. From GAO/NSIAD-95-116 (1995), p. 17

Unlike GPS or other radionavigation systems, TERCOM did not provide continuous position information. Instead, it was an adjunct to the cruise missile’s inertial navigation system (INS), which used gyroscopes and accelerometers to measure the weapon’s movement. What TERCOM did was provide updates to the INS by comparing the measurements from the missile’s radar altimeter with stored information on the terrain the missile was flying over. Assuming this was a sufficiently “bumpy” area, the altimeter measurements should match only location – providing a precise position fix. By using TERCOM to update its location three times during flight, the cruise missile had far superior accuracy to a missile using only inertial navigation. (On non-nuclear missiles, a separate system known as Digital Scene Matching Area Correlation [DSMAC] offered even more precise guidance for the final stage of the flight.)

Making Maps for TERCOM

The terrain information which the TERCOM system used (called a “matrix”) was based on a database of Digital Terrain Elevation Data (DTED), which contained the elevation above sea level for all the points on a (roughly) 300 foot grid. Luckily enough, the Defense Mapping Agency (DMA) had already been collecting this information for a far more mundane purpose: to use in flight simulators. TERCOM, however, required much, much more of this information. The DMA had been involved in the early testing of TERCOM but the agency wasn’t involved in the decision to put the cruise missiles using the technology into full-scale development. DMA had only been creating TERCOM matrices by hand (so to speak), and now it was looking at the requirement for more than 8,000 of them. According to Jay L. Larson and George A. Pelletiere, “it took DMA five years of ‘crash’ effort to fulfill these requirements.” Demands for TERCOM matrices had to be triaged, with three-quarters of the effort going to the ALCM and the other quarter to the submarine-launched and ground-launched cruise missile programs. If the US military had gone to war in the interim, they would have been unable to use cruise missiles except in particular areas.

To extend the Digital Terrain Elevation Data database over the entire world, and particularly over areas like the interior of the Soviet Union, the DMA used photography collected by the United States’ reconnaissance satellites. The technical principle involved, stereogrammetry, had been well understood since the First World War. Start with two photographs of the same scene taken from slightly different vantage points, such as two moments along the flight path of a plane or satellite. Look at the two images, one with each eye, and move them until they like a single three-dimension image – just like how the human brain normally combines the images from each eye … if your eyes were several hundred meters apart.

If you know the distance between the points from which the images were taken (that hundred metre bridge of the nose) and the angles between the two viewpoints and an object in the image, you can calculate the size of that object. Add in the altitude from which the images were taken and you can calculate the elevation. Conventionally, stereogrammetry is done using a human brain to process illuminated transparencies or with mirrors and hardcopy prints. In the early 1960s computerized system like the Universal Automated Map Compilation Equipment (UNAMACE) took over, speeding up the process tremendously.

UNAMACE. From Hexagon (KH-9) Mapping Camera Program and Equipment (CSNR, 2012), p. 301.

Pictures of UNAMACE, from Hexagon (KH-9) Mapping Camera Program and Equipment (CSNR, 2012), p. 301.

Even once TERCOM matrices were readily available, the mission planning process remained long and complex. During the first Gulf War, it had to be performed at a specially equipped facility (one of the Navy’s two Cruise Missile Support Activities) and took between 24 and 80 (!) hours.

The US cruise missile program attracted a lot of controversy in the 1970s and 1980s, particularly from critics who argued that a new, flexible, and less detectable nuclear weapons delivery system could be destabilizing or even provocative, but TERCOM itself did not itself draw that much of the attention. The exception was up in Canada, where a guidance system subcontractor found itself the focus of a blast of “direct action” against the cruise missile.

Forward to Part Two

NASA’s Graphics Standards Guide is Back

I’m not sure whether it was the Kickstarter to do an high-quality reprint of the 1976 NASA Graphics Standards Guide or the publication of the agency’s own history book Emblems of Exploration: Logos of the NACA and NASA, but the National Aeronautics and Space Administration has put up a PDF of the classic guide on its website.

I don’t want to get into the middle of the fight over whether “the meatball” or “the worm” is the better NASA emblem, aside from noting that both seem far better to me than the official seal with its mustard yellow planet. There’s a lot more the guide than just the introduction of the NASA logotype (“the worm”).

ThNASA_GSDp41e Graphics Standards Guide includes guidance for typography (use Helvetica, Future, Garamond, or Times New Roman), publication layouts, signage, and vehicle markings. That includes instructions on how to paint a Grumman Gulfstream airplane (“The windows determine the width and placement of the blue stripe. Fuselage markings align with the top edge of the windows”) or a Lockeed F-106 (“The bottom of the blue stripe aligns with the leading edge of the wings. Fuselage markings are flush left with the tail markings”). The two pages of spacecraft markings are more informational than practical, one expects.NASA_GSDp54NASA_GSDp56