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'Wide-Eyed Dreamers': 20 Years Since STS-77's Record-Setting Rendezvous Mission (Part 1)
By Ben Evans, on May 21st, 2016

The Inflatable Antenna Experiment (IAE) extends from the SPARTAN-207 free-flying satellite, after deployment. Photo Credit: NASA, via Joachim Becker/

Early on 20 May 1996, NASA astronaut Mario Runco, Jr., grappled SPARTAN-207—a small, free-flying spacecraft, equipped with a very unique experiment—and lifted it from Shuttle Endeavour’s payload bay with the Canadian-built Remote Manipulator System (RMS) mechanical arm. Together with his five crewmates, Runco had launched just 24 hours earlier, kicking off the 10-day STS-77 mission. And on STS-77, the frequent-flying SPARTAN would undertake its most ambitious exercise yet. Runco released the satellite on time at 7:29 a.m. EDT, into orbital darkness, after which Commander John Casper maneuvered Endeavour to a distance of about 820 feet (250 meters).

Once there, Casper held his ship’s position for about an hour, before conducting a partial flyaround, to a point directly “above” the satellite. Next, he began an 80-minute period of station-keeping to observe a quite remarkable experiment: an experiment with potentially enormous benefits for a range of applications, from space radar to mobile communications, from astronomy to Earth observations, and from environmental research to the analysis of soil moisture and salinity. In fact, STS-77—which was in orbit 20 years ago, this week—set the space shuttle’s myriad capabilities to work and served as a critical pathfinder for future research aboard the International Space Station (ISS).

Two hours after Runco released SPARTAN-207, the Inflatable Antenna Experiment (IAE) got underway. Designed and built by L’Garde, Inc., a small aerospace company, based in Tustin, Calif., together with NASA’s Jet Propulsion Laboratory (JPL) of Pasadena, Calif., it sought to inflate a 46-foot-wide (14-meter) Mylar antenna dish, at the apex of three deployable struts, as part of an investigation into how large, expandable structures behaved and functioned in the microgravity environment. Since 1971, L’Garde had pioneered the construction of thin-skinned, multi-task balloons and its products included a decoy missile for the Department of Defense.

The circular expanse of the Inflatable Antenna Experiment (IAE) is juxtaposed over Earth in the STS-77 crew’s official patch. Image Credit: NASA, via Joachim Becker/

It had long been recognized that the mass and stowed volume of inflatable space components was significantly less than an equivalent solid structure and that this carried the potential to reduce by 10-100 times the cost of future missions. In 1988, L’Garde began working on the IAE, and, according to the company’s founder and vice president, Alan Hirasuna, the $14 million cost of this inflatable antenna was a mere fraction of the $200 million to build a similar-sized antenna with more conventional materials. Moreover, its compactness and 130-pound (60-kg) weight meant that it could be carried aboard much smaller launch vehicles.

At 9:38 a.m. EDT, as six pairs of astronaut eyes and a battery of still, video, and motion-picture camera equipment aboard Endeavour looked on, SPARTAN-207 commanded the deployment of IAE’s supporting tripod, each of whose neoprene-coated Kevlar limbs unfolded to 92 feet (28 meters). At their apex, a canister of pressurized nitrogen gas inflated the antenna, in just five minutes, to its full diameter of 46 feet (14 meters). With a silver reflective surface on its topside and a clear underside, the IAE was then observed and photographed over the following 90 minutes by the STS-77 crew and illuminated by an array of lights aboard SPARTAN-207 to precisely measure its smoothness. The antenna was then jettisoned, steadily moving “below” and “ahead” of the satellite, as Casper executed a Reaction Control System (RCS) thruster firing to maneuver Endeavour “above” and “behind” it. They would maintain a distance of 55-70 miles (90-110 km) from SPARTAN-207—which also carried a number of other experiments, including a new solid-state recorder and advanced integrated circuits—for the next two days.

By the evening of 20 May, a few hours after deployment, the discarded IAE was being tracked at a distance of more than 115 miles (185 km) “ahead” and “below” the shuttle and, judging from its large size and relatively low weight, trajectory planners expected it to re-enter Earth’s atmosphere within 17-24 hours. As it happened, IAE finally re-entered early on 22 May, the same day that Casper and his crewmates re-rendezvoused with SPARTAN-207 to begin retrieval operations.

Awakened from their slumbers that morning to the sound of Fifth Dimension’s song Up, Up and Away, in honor of their completed experiment, the astronauts wasted no time preparing their equipment for the rendezvous. In a similar manner to the approach procedures followed by several earlier shuttle crews, a Terminal Initiation (TI) burn of Endeavour’s RCS thrusters kicked off the final approach and Casper guided his ship to just 35 feet (10 meters) from SPARTAN-207, whereupon astronaut Marc Garneau—who in October 1984 had become the first Canadian in space—extended the RMS and grappled the satellite at 10:53 a.m. EDT. As the satellite hung on the end of the arm, the crew performed a video and photographic survey, before it was berthed in the payload bay.

With the successful retrieval of SPARTAN-207, the shuttle’s mission was barely a quarter complete, but its wide range of scientific and technological experiments were well underway. Flying for the fourth time as a research facility on STS-77, the commercial Spacehab was not dissimilar in appearance to the European Space Agency’s (ESA) Spacelab module, but with several key differences: It was smaller, consuming just a quarter of the payload bay, and it was designed and built not by governments, but by private enterprise. It also differed from Spacelab in overall physical shape; it was cylindrical, but with a flat roof. When the module rose from Earth for the first time on STS-57 in June 1993, it marked the realization of a decade-long dream for aerospace engineer Bob Citron, who founded Spacehab in 1983 and incorporated it the following year.

The struts of the Inflatable Antenna Experiment (IAE) deploy in the minutes after leaving the vicinity of Endeavour. Photo Credit: NASA, via Joachim Becker/

“People often ask me why I started Spacehab,” Citron recalled years later, “and my response usually goes something like this: It took a small group of wide-eyed dreamers and determined space enthusiasts who believed we could pull it off. We didn’t have a clue about the enormous problems we would encounter and the nearly insurmountable technical, financial and institutional roadblocks that would stand in our way. Nobody had done anything like this before.” The primary goal of Citron, who died in January 2012, was to create the world’s first privately funded company to support human space missions, using the payload bay of the shuttle as a carrier of commercial pressurized research modules.

The need for such provision was self-evident. In the shuttle’s pre-Challenger heyday, many missions were planned each year and a primary thrust of the Reagan Administration’s 1983 space policy was for the commercial exploitation of the microgravity environment. Middeck lockers were being used to carry out experiments in crystal growth and pharmaceutical research, but the limited volume meant that their commercial viability was restricted. The Spacehab module, accessed via a tunnel connected to the middeck airlock hatch, measured 9.2 feet (2.8 meters) long, 11.2 feet (3.4 meters) high, and 13.4 feet (4.1 meters) across the width of the payload bay and could increase the shuttle’s pressurized envelope by almost 1,100 cubic feet (31 cubic meters), more than tripling the available working and storage space. The module, which weighed approximately 9,480 pounds (4,300 kg), could house a total payload of more than 2,870 pounds (1,300 kg), including up to 61 lockers and two large racks.

After incorporating Spacehab in 1984, Citron admitted that the company was “on the verge of failure on a number of occasions during its first years,” until he brought in critical professional management personnel and “things started to happen” through negotiations with NASA, the Italian Alenia Spazio, and German MBB-Erno organizations, as well as Martin Marietta and McDonnell Douglas. By the end of 1985, only weeks before the Challenger tragedy, Spacehab was tentatively scheduled for its first flight in 1987 and a lease of $5 million per mission was quoted by Flight International. Early plans called for the assembly of three modules, but center-of-gravity issues gave NASA cause for concern and threatened to affect the placement of other cargo in the payload bay.

Ultimately, McDonnell Douglas was selected as the lead contractor and a decision was made to build two flight modules and an engineering test model. Other worries lingered, but in late 1986 Spacehab signed a Space System Development Agreement, in which NASA agreed to fly five inaugural missions. By October 1987, 42 requests had been received, with lockers priced at $300,000 for non-government users and $100,000 for government agencies and contractors. The concept was now growing from initial designs into reality. In September 1989, Patent No. 4,867,395 for a “Flat End-Cap Module for Space Transportation System” was awarded to Spacehab, Inc., by the U.S. Patent Office.

STS-77’s primary cargoes dominate this view of Endeavour’s payload bay in orbit. In the foreground is the Spacehab-4 module, with SPARTAN-207 visible in the background. Photo Credit: NASA, via Joachim Becker/

Hopes to fly the modules on very early post-Challenger missions received a rude awakening, however, and it was at least three years after the resumption of shuttle operations before a first flight could be realistically expected. According to NASA’s April 1988 schedule, Spacehab-1 was listed as a primary payload on STS-51 in June 1991. This schedule slipped and, at length, the first module was not unveiled until early 1992 at the custom-built Spacehab Payload Processing Facility (SPPF) at the Kennedy Space Center (KSC) in Florida. By this time, under the Commercial Middeck Augmentation Module procurement, initiated in February 1990 and formally signed the following December, NASA agreed to lease a total of 200 Spacehab lockers at a cost of $184.2 million. Over the coming years, the SPPF would host more than a hundred astronauts and cosmonauts, enabling them to train on real experiment hardware.

However, all was not smooth sailing for Spacehab, which supported three dedicated science missions between June 1993 and February 1995 and was embarking on its fourth “stand-alone” flight on STS-77. In the aftermath of the first flight, however, few contracts outside NASA materialized for the laboratory, in spite of aggressive efforts to market its capabilities. This was due to a number of factors, chiefly high Spacehab locker prices in the region of $925,000 and anticipated commercial prospects failing to materialize. “No commercial companies are ready yet to make an independent commitment to research,” said Rebecca Gray, Spacehab’s manager of government and public relations, in a Flight International interview in the fall of 1995, despite the company having delivered its services on time and on budget.

NASA’s contract was renegotiated to cover four missions, of which STS-77—whose module, though full, was dominated by NASA-funded experiments—was to be the last. “If NASA requires more flights of this nature,” Flight International continued, “it is likely only to be at a rate of about one flight a year and another contract will have to be negotiated.” The company had already signed a $54 million lease contract with NASA to utilize its modules for logistics on several missions to Russia’s Mir space station in 1996-1998. It also invested $15 million of its own capital to develop a “double” logistics module to be used “as a laboratory and a cargo carrier,” with the capacity to transport up to 6,000 pounds (2,720 kg) of payloads to Mir, as well as soft-stowage canvas bags for supplies. However, the option for more “stand-alone” research missions would be renegotiated and two would be flown: STS-95 in late 1998, which saw Project Mercury pioneer John Glenn return to space, and STS-107 in early 2003, the final voyage of Columbia.

More than 90 percent of the Spacehab-4 payloads were directly sponsored by NASA’s Office of Space Access and Technology (OSAT), through its Commercial Space Centers and their industrial partners, as well as by several of the agency’s field centers. Right from the outset, STS-77 was dedicated to opening the commercial frontier of space, with the Spacehab module hosting almost 3,000 pounds (1,400 kg) of equipment in 28 lockers, four soft stowage bags, and a pair of single racks to support around a dozen investigations in the fields of biotechnology, electronic materials, polymers, and agriculture. These included the Advanced Separation Process for Organic Materials (ADSEP) to demonstrate separation and purification technologies for potential medical and pharmaceutical applications, the Commercial Generic Bioprocessing Apparatus (CGBA) and Plant Generic Bioprocessing Apparatus (PGBA) to investigate the influence of microgravity on molecular, cellular, tissue, and small animals and plants—as well as studying compounds which might someday prove beneficial as chemotherapy and anti-malaria agents—and the Fluids Generic Bioprocessing Apparatus (FGBA) to explore the management of liquids in space.

The STS-77 crew. Seated are John Casper (right) and Curt Brown (left), with Dan Bursch, Mario Runco, Marc Garneau, and Andy Thomas standing. Photo Credit: NASA, via Joachim Becker/

The latter received corporate sponsorship from the Coca-Cola Company, which flew both Coke and Diet Coke aboard STS-77. The experiment, noted NASA, “will provide a testbed to determine if carbonated beverages can be produced from separately stored carbon dioxide, water and flavored syrups and determine if the resulting fluids can be made available for consumption without bubble nucleation and resulting foam formation.” If so, it was hoped that such experiments might lead to a better understanding of altered tastes in target populations, such as the elderly, and how future drinks could be tailored to increase hydration. International co-operation on STS-77 was underpinned by the presence of the Commercial Float Zone Furnace (CFZF), a joint effort between the respective space agencies of the United States, Canada, and Germany to produce large, ultra-pure compound semiconductor and mixed-oxide crystals of gallium arsenide and gallium antimonide for electronic devices and infrared detectors. Another payload, the Space Experiment Facility (SEF), used a furnace to produce through vapor-diffusion a series of crystals of mercurous chloride, which is considered a valuable electro-optical material of commercial interest, and to bond powdered metals through the liquid-phase sintering process, as part of efforts to design new composites for the machine tool industry.

STS-77 was shaping up to be not only an ambitious mission in space science and technology, but as an important demonstrator of the shuttle’s myriad capabilities as a research platform, as a satellite deployment and retrieval facility, and as full-up precursor for the kind of work which would someday become “routine” aboard the International Space Station (ISS). Indeed, three members of the STS-77 crew—Marc Garneau, Andy Thomas, and Dan Bursch—would help build the multi-national station in the coming years: Garneau would perform critical robotics work in support of the installation of its first set of power-producing solar arrays, whilst Thomas would spacewalk outside it and Bursch would be a member of one of its earliest long-duration crews.


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'An Amazing and Wonderful Experience': 20 Years Since STS-77’s Record-Setting Rendezvous Mission (Part 2)
By Ben Evans, on May 22nd, 2016

STS-77’s primary cargoes dominate this view of Endeavour’s payload bay in orbit. In the foreground is the Spacehab-4 module, with SPARTAN-207 visible in the background. Photo Credit: NASA, via Joachim Becker/

Twenty years ago this week, six men orbited Earth aboard Shuttle Endeavour on one of the most complex research flights ever conducted in the program’s 30-year history. With such a large number of payloads aboard, it was imperative for the STS-77 crew—Commander John Casper, Pilot Curt Brown, and Mission Specialists Andy Thomas, Dan Bursch, Mario Runco, and Canada’s Marc Garneau—to begin activating as many experiments as possible on the first day of their 10-day flight. As described in yesterday’s AmericaSpace history article, STS-77 was tasked with a multitude of experiments in the commercial Spacehab-4 laboratory and the deployment and retrieval of as many as four free-flying satellite payloads. Launch was originally targeted for 16 May 1996, but was pushed back to the 19th, since the earlier date was not available to NASA on the Eastern Range schedule. The crew had been training for the mission for almost a year, having been assigned in June 1995, and took their seats aboard Endeavour for an early-morning liftoff at 6:30 a.m. EDT.

“Really an amazing and wonderful experience,” was the opinion of first-time flier Andy Thomas, an Australian-born U.S. astronaut, who was seated on Endeavour’s flight deck for ascent. “I could look out the overhead windows with a wrist-mirror. I could see the flame in the flame trench, prior to liftoff; I could see the flash of the [Solid Rocket Booster] ignition; and then feel the lurch as we were accelerated upwards.”

Following this smooth ascent into the steadily retreating darkness of a Florida dawn, the six men reached orbit, doffed their pressure suits, and set to work. In spite of a problem with a cooling device for one of the orbiter’s Hydraulic Power Units (HPUs), Thomas and Garneau opened the hatch into the Spacehab module, floated inside, and began powering up experiments. Later in the day, Thomas also checked out the shuttle’s Canadian-built Remote Manipulator System (RMS) mechanical arm, ahead of the deployment of their SPARTAN-207 satellite payload. As the only first-time flier on STS-77, Thomas served as the payload commander, with overall responsibility of all of the mission’s research goals.

In the pre-dawn darkness of 19 May 1996, Commander John Casper (front right) leads his crew to the launch pad. Photo Credit: NASA, via Joachim Becker/

In Endeavour’s middeck, the Immune-3 experiment tested the ability of insulin-like growth factor to prevent or reduce the detrimental effects of microgravity exposure on the immune and skeletal systems of rats, whilst three investigations sought to crystallize various protein crystals with objectives to address a range of diseases and the Gas Permeable Polymer Membrane (GPPM) pioneered the development of enhanced polymers for manufacturing rigid gas-permeable contact lenses. The National Institutes of Health (NIH) provided a tissue culture incubator, and its experiments focused on the influence of weightlessness on the muscle and bone cells of chicken embryos. Elsewhere, the metamorphosis of tobacco hornworm was examined, as part of efforts to understand the synthesis of muscle-forming proteins, the processes of fertilization, and embryonic development of small aquatic organisms, including starfish, mussels, and sea urchins. In fact, the latter was one of the first experiments to be activated by Mario Runco, a few hours after liftoff.

If the crew cabin and the Spacehab module both represented a hive of activity during STS-77, then the payload bay was similarly packed with experiments. The Brilliant Eyes Ten Kelvin Sorption Cryocooler Experiment (BETSCE) was carried as part of ongoing efforts to develop technologies to rapidly cool infrared and other sensors to near-absolute zero Kelvin (-273.15 degrees Celsius). BETSCE employed a highly reliable “sorption cooler,” which exhibited virtually no detrimental effects of vibration, to cool infrared sensors to just 10 degrees Kelvin (-263.1 degrees Celsius). “Sorption coolers work by using specialized metal alloy powders, called metal hydridges, that absorb the hydrogen refrigerant through means of a reversible chemical reaction,” NASA explained in its STS-77 pre-flight press kit. “In the sorption compressor, the metal powder is first heated to release and pressurize the hydrogen, and then cooled to room temperature to absorb hydrogen and reduce its pressure. By sequentially heating and cooling the powder, the hydrogen is circulated through the refrigeration cycle. Ten degrees Kelvin is achieved by expanding the pressurized hydrogen at the cold tip of the refrigerator. This expansion actually freezes the hydrogen to produce a solid ice cube. The heat load generated by the device being cooled then sublimates the ice. This closed-cycle operation is repeated over and over.”

Previous astronomy missions which conducted their studies in the infrared needed to carry large, heavy, and expensive dewars of liquid helium or hydrogen to accomplish operating temperatures as low as 10 Kelvin, but the duration of their useful lives were restricted when the cryogens eventually boiled off and ran out. “The ability to achieve a lifetime of ten or more years, with no vibration,” NASA added, “opens the door to a wide variety of future missions that could benefit from this novel technology.”

Mario Runco works with camera equipment at Endeavour’s flight deck windows. Photo Credit: NASA, via Joachim Becker/

Mounted atop a Hitchhiker structure in Endeavour’s payload bay was the Technology Experiments for Advancing Missions in Space (TEAMS), provided by NASA’s Goddard Space Flight Center (GSFC) of Greenbelt, Md., which featured four investigations: the GPS Attitude and Navigation Experiment (GANE) to gauge the effectiveness of Global Positioning System technology, which was then in its infancy, the Vented Tank Resupply Experiment (VTRE) to evaluate improved methods for refueling in space, the Liquid Metal Thermal Experiment (LMTE) to test potassium-filled liquid metal heat pipes in microgravity, and the Passive Aerodynamically Stabilized Magnetically Damped Satellite-Satellite Test Unit (PAMS-STU).

The latter was of particular interest on STS-77, for its presence led the mission to establish a new record as the first shuttle flight to complete as many as four separate rendezvous operations. Developed by NASA-Goddard, PAMS-STU was a technology demonstrator for the principle of natural “aerodynamic stabilization,” which it was hoped might increase the orbital lifetime of satellites by reducing or eliminating the need for large quantities of attitude-control propellants. “Aerodynamic stabilization works the same way as a dart,” NASA explained shortly before the STS-77 launch. “The front of the dart is weighted and once the dart is thrown, it will always right itself with the head facing forward. In the same manner, the PAMS-STU satellite will eventually be oriented with the heavy end facing forward in orbit. This principle can be used to partially control the attitude of small satellites.”

On the fourth day of the mission, 22 May 1996, the PAMS-STU operations got underway when Runco deployed the cylindrical, 2 x 3 foot (60 x 90 cm) satellite at 5:18 a.m. EDT from a canister at the rear end of Endeavour’s payload bay. As intended, it drifted away from the orbiter in a rotating, unstable attitude, in order to evaluate how quickly and effectively it could stabilize itself using natural aerodynamics. Casper and Brown maneuvered the shuttle to a distance of nine miles (14.6 km) to begin the first of three scheduled rendezvous exercises. A little over 4.5 hours later, they drew closer to about 1,970 feet (600 meters) to track PAMS-STU with the laser-based Attitude Measurement System (AMS) in the payload bay. However, it was noticed that the satellite had not yet stabilized itself and a strong “lock” could not be obtained. With two further rendezvous sessions, each lasting around 6.5 hours, planned for 24 and 25 May, Endeavour withdrew to a maximum distance of about 64 miles (103 km).

During their second rendezvous on 24 May, Casper and Brown reached a station-keeping point just 1,700 feet (520 meters) from PAMS-STU and held their position for more than six hours, until a problem arose with the Space Experiment Facility (SEF) in the Spacehab module and Andy Thomas was called away to commence troubleshooting. It was clear from video imagery acquired by the crew that the satellite had begun to stabilize itself with natural aerodynamic forces, albeit somewhat slower than expected. The third and final rendezvous was postponed by 24 hours, until 26 May, in order for engineers to evaluate the AMS, which provided high-accuracy data on the behavior and relative motions of PAMS-STU. Although it had proven its ability to track the small satellite, the laser system seemed to be locking onto an unknown target (perhaps a structure in the payload bay) and was subjected to intensive troubleshooting.

Endeavour alights on the Shuttle Landing Facility (SLF) on 29 May 1996, within sight of the Vehicle Assembly Building (VAB). Photo Credit: NASA, via Joachim Becker/

Throughout those 24 hours, Endeavour moved away from the satellite, reaching a maximum distance of about 115 miles (185 km), before Casper executed a Reaction Control System (RCS) thruster firing on the 26th to begin the third period of rendezvous. Closing on PAMS-STU at about 2.3 miles (3.7 km) per orbit, this time the operation ran by the book, with Casper and Brown guiding their ship to within 1,800 feet (550 meters) of their quarry. As the orbiter’s payload bay faced the satellite, NASA-Goddard flight controllers successfully commanded the AMS to calculate its attitude to within one-tenth of a degree. The pilots moved closer, to just 1,640 feet (500 meters), and held their position for seven hours and 45 minutes. This was about 70 minutes longer than planned, as controllers verified that the AMS laser was impinging on PAMS-STU’s reflectors. Throughout the third rendezvous, the satellite remained very stable and validated the aerodynamic stabilization concept.

Departing PAMS-STU for the final time, the STS-77 crew entered the final days of their mission, heading for a landing at the Kennedy Space Center (KSC) in Florida on 29 May 1996. It was expected that the small satellite would re-enter the upper atmosphere to destruction after a few weeks, although trajectory specialists noted that it might remain aloft until as late as January 1997. (As circumstances transpired, PAMS-STU ended its days on 26 October 1996.)

Weather forecasts at KSC and Edwards Air Force Base, Calif., were highly favorable for an on-time landing, with two opportunities available at each site on the 29th. The first opportunity to land in Florida was taken, and Casper executed the de-orbit burn at 6:09 a.m. EDT and guided his ship to a smooth touchdown on Runway 33, precisely an hour later, at 7:09 a.m. With more than 21 cumulative hours of formation flying, Endeavour’s crew had secured a new record for themselves by becoming the first shuttle mission to execute four discrete periods of rendezvous and the longest amount of rendezvous ops. STS-77 also marked the first shuttle flight to be powered into orbit by a full set of three Block I Space Shuttle Main Engines (SSMEs) and the first to be fully controlled from the new Mission Control Center (MCC) at the Johnson Space Center (JSC) in Houston, Texas.


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