GOES-R Set for Saturday Launch, Ready for Quantum Leap in Earth Weather Watching

For only the fourth occasion in its history, the Atlas V will rise from Cape Canaveral Air Force Station, Fla., in its second-most-powerful active operational variant on Saturday evening. The rarely used “541” configuration of United Launch Alliance’s (ULA) highly reliable workhorse—previously employed to deliver the Curiosity rover to the Red Planet in November 2011, as well as a pair of National Reconnaissance Office (NRO) payloads in April and December 2014—will this time carry the latest member of NASA’s Geostationary Operational Environmental Satellite (GOES-R) aloft. From its orbital position, which will attain an apogee of approximately 22,300 miles (35,800 km), the Lockheed Martin-built satellite is the first member of the fourth generation of spacecraft which have revolutionized our understanding of our Home Planet since the mid-1970s.

Operated by the United States’ National Environmental Satellite, Data and Information Service (NESDIS), the multi-spacecraft GOES network is responsible for weather forecasting, storm tracking, and meteorological research from geostationary orbit. The first member of the family, GOES-1, was launched out of Cape Canaveral in October 1975 and positioned over the Indian Ocean. It returned its first image of the Home Planet nine days after launch. Over the course of almost a decade, it performed day-and-night cloud observations and contributed significantly to the evolving science of global weather prediction and forecasting. In June 1977 and June 1978, GOES-2 and GOES-3 were launched, although their lengthy careers encompassed far more than environmental research; both were subsequently repurposed as communications satellites, supporting the Pacific islands and the National Science Foundation (NSF), serving Amundsen-Scott South Pole Station. GOES-3 remained functional for almost four decades, until it was finally decommissioned in June 2016.

It became customary for each satellite to be identified via a letter of the alphabet before launch and renamed with a number after entering service in geostationary orbit. Consequently, GOES-D—launched in September 1980—was redesignated “GOES-4” at the onset of operations. Unlike its three predecessors, which were built by Ford Aerospace, GOES-4 was fabricated by Hughes, based upon the company’s HS-371 “bus,” and interestingly its claim to fame is that in November 1988 it became the first satellite ever to be raised out of geostationary altitude and into a “graveyard” orbit for disposal.

GOES-5 rose to orbit in May 1981, but its on-board Visible Infrared Spin-Scan Radiometer (VISSR) failed three years later, requiring GOES-1 and GOES-4 to be reactivated to fill the gap in coverage. Operations resumed with GOES-6, launched in April 1983, which was repositioned a year later to cover its ailing predecessor. More bad luck was afoot, however. On 3 May 1986—a mere 13 weeks after the loss of Challenger—GOES-G was lost, when its Delta launch vehicle suffered a premature first-stage engine shutdown and exploded in flight. The loss of the ordinarily reliable Delta occurred 71 seconds after liftoff, chillingly close to the same duration of the ill-fated shuttle flight.

Originally, the next GOES was targeted for a late 1986 launch, but was postponed into the spring of the following year. At length, GOES-7 settled safely into orbit in February 1987 to begin its full-time role as replacement for GOES-5. Meanwhile, GOES-6 suffered the failure of its on-board imager in January 1989 and the inevitable consequence was that GOES-7 was left as the sole operational member of the fleet for the next five years. However, the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) leased its Meteosat-3 satellite to the program in 1992, enabling the continued provision of GOES operations in both East and West locations.

In its later life, GOES-7—the final member of the first-generation GOES—provided communications services for the Pacific islands, before its eventual movement to a graveyard orbit in 2012. By this time, the second and third generations of the program were well underway. The inaugural member of the second generation, the Space Systems/Loral (SS/L)-built GOES-8, became the first GOES spacecraft to launch atop an Atlas vehicle when it reached orbit in April 1994. Despite a design flaw in the motor windings of its on-board imager/sounder, it remained in service for almost a full decade. GOES-9, launched in May 1995, suffered a similar problem with its imager/sounder, as well as a reaction-wheel glitch which hampered its ability to achieve effective attitude control. Relegated to backup duty, and used by the Japan Meteorological Agency in its later career, it was replaced by GOES-10, which launched in April 1997.

However, GOES-10 encountered its own problems. Soon after entering orbit, the satellite experienced a malfunction of its solar array tracking system, which necessitated a lengthy period of troubleshooting and GOES-10 was itself relegated to backup service. In the summer of 1998, following GOES-9’s reaction-wheel problem, a decision was taken to bring GOES-10 back online and it resumed operations in August. It remained functional for the next eight years, before GOES-11 launched in May 2000 and eventually took its place in 2006 when GOES-10 came close to running out of attitude-control propellant. Next up was GOES-12, the last member of the second generation of satellites, which reached orbit in July 2001. During its lifetime, GOES-12 took over the duties of one of its older siblings, acted as an on-orbit spare and trialed a full-disk Solar X-ray Imager for the enhanced prediction and monitoring of solar weather.

Unfortunately, the imager failed in April 2006, due to an electrical system malfunction, but upgraded versions have flown aboard subsequent GOES missions with significant success. From the end of 2007, GOES-12 began to suffer a series of thruster issues, leading mission planners to bring the aging GOES-10 back into service to replace it. These thruster issues ultimately led to a complete loss of control in December 2008, although GOES-12 was recovered and continued operations until it was decommissioned in August 2013.

The currently operational third generation were all built by Boeing, based upon its 601 bus, which is also presently utilized by NASA’s Tracking and Data Relay Satellite System (TDRSS) network. In May 2006, June 2009 and March 2010, the GOES-13, 14 and 15 satellites entered service, having launched atop Delta IV boosters out of Cape Canaveral Air Force Station. (A fourth satellite was contracted, but later canceled.) All three remain fully functional to this day, monitoring the destructive progress of Superstorm Sandy and rapidly scanning the motion of Tropical Storm Isaac during the summer and fall of 2012, whilst GOES-15 has used its five-channel multispectral imager to acquire visible-light and infrared imagery of the continental United States. The satellites’ Solar X-ray Imagers have also been routinely put to work observing solar flare events and they have been tasked with monitoring Earth’s magnetosphere and characterizing the cosmic background radiation and charged particle environments. Yet the gremlins which struck earlier GOES missions have not been absent from the third generation. One solar flare in December 2006 proved so fierce that it damaged GOES-13’s Solar X-ray Imager.

Tomorrow’s launch of GOES-R—to be renumbered “GOES-16” when it begins operations—will mark the 17th spacecraft of the series, though only the 16th to successfully achieve orbit, when one counts the ill-fated GOES-G. It is the first member of the fourth-generation GOES and has been built by Lockheed Martin, based upon its L2100 “bus.” This modular design has already been employed by several communications satellites and the L2100A version to be used by GOES-R can provide up to four kilowatts of electrical power for its spacecraft and payload, via a pair of paddle-like solar arrays.

When it enters service, GOES-R will provide for advanced imaging in support of better weather forecasts, as well as real-time lightning mapping and enhanced solar monitoring. The three-axis-stabilized spacecraft weighs approximately 6,170 pounds (2,800 kg) and represents a quantum leap in capability above its predecessors, boasting three times more spectral information, four times higher spatial resolution, five times faster coverage, and significantly enhanced functionality in providing advance warnings of storms, tornadoes, hurricanes, and solar-induced events, ranging from geomagnetic storms to Coronal Mass Ejections (CMEs).

GOES-R carries three types of instruments. Its “Earth-facing” suite consists of the Earth Baseline Imager (ABI) for visible and infrared observations of our planet’s weather and climate, enabling storms to be tracked in their early stages, and the Geostationary Lightning Mapper (GLM) for continuous, day-and-night measurements of intra-cloud lightning associated with severe storms. It is hoped that their combined data will improve warning times ahead of tornadoes, as well as aiding the development of climatological models, thunderstorm warnings, and improving aviation weather services. Its “Sun-facing” instruments are the Solar Ultraviolet Imager (SUVI) and the Extreme Ultraviolet and X-ray Irradiance Sensors (EXIS) for extreme-ultraviolet and X-ray analyses of our parent star’s active regions, including solar flares and filaments, which precipitate the emergence of CMEs. Since these dramatic events can have dire implications upon Earth’s communications and navigational capabilities—as well as orbiting satellites and crews aboard the International Space Station (ISS)—early warnings are paramount. Finally, the third set of instruments are “Space-facing” and comprise the Space Environment In-Situ Suite (SEISS) and the Magnetometer (MAG) to observe proton, electron, and heavy-ion fluxes at geostationary altitude, some 22,300 miles (35,800 km) above Earth. In addition to assessing radiation hazards for humans and satellites at this altitude, these instruments will improve solar energetic particle forecasts and provide a better understanding of the dynamic conditions in Earth’s outer magnetosphere.

With the award of contracts for GOES-R’s instruments dating back to 2006, Lockheed Martin was selected in December 2008 to build and integrate a pair of spacecraft, at an estimated cost of $1.09 billion. At the time of the award, it was noted that GOES-R’s highly advanced instruments would provide approximately 50 times more weather and climate data than was available at the time. In the words of Mary Kicza of the National Oceanic and Atmospheric Administration (NOAA), the satellite would allow the U.S. public to “see real life-saving benefits,” including “more timely forecasts and warnings for severe weather.” In April 2012, United Launch Alliance (ULA) was selected to deliver the two new satellites—designated GOES-R and GOES-S—into orbit, atop Atlas V 541 boosters. Initial plans called for the new GOES members to launch in October 2015 and February 2017, although this schedule has since met with delay.

By last fall, it was hoped that GOES-R might fly in March 2016, but this date also proved untenable. Last December, it was revealed that although thermal vacuum testing of the spacecraft had been successfully completed, a decision had been made to move the launch to no sooner than October 2016, enabling teams to “best mitigate possible schedule risks.” In spite of the delay, the GOES-R program was rated as “Green,” indicating that it was ready for operations and data-processing after reaching orbit. Mechanical and other tests were conducted in the spring and the spacecraft was fully integrated and ready for shipment to Florida by the end of July.

On 22 August 2016, GOES-R was delivered to the Cape, aboard a U.S. Air Force C-5 Galaxy cargo aircraft. By this stage, its launch date had slipped slightly to no earlier than 4 November, although a combination of factors—notably the ravages of Hurricane Matthew—would contribute to pushing that date back to mid-month. After Matthew had passed, the ULA launch team began an initial assessment of their Cape infrastructure and determined a new planning date of 16 November, pending approval from the 45th Space Wing at Patrick Air Force Base. Issues pertaining to the Atlas V booster earmarked for the WorldView-4 mission out of Vandenberg Air Force Base, Calif., precipitated another short delay and eventually Eastern Range approval was granted for a launch during a one-hour “window” from 5:42 through 6:42 p.m. EST on 19 November.

As these discussions continued, preparations to integrate GOES-R into its two-piece (or “bisector”) Short Payload Fairing continued. This bulbous fairing measures 17 feet (5 meters) in diameter and offers an unusual “top-heavy” appearance for the Atlas V 541, whose Common Core Booster (CCB), by contrast, is just 12.5 feet (3.8 meters) wide. After encapsulation into the payload fairing, the combo was transported from the Astrotech processing facility to SLC-41 and mounted atop the booster.

When fully integrated, the Atlas V 541 for this mission stands 197 feet (60 meters) tall. This configuration of the Atlas V—so named in recognition of the 17-foot (5-meter) payload fairing, the presence of four side-mounted, solid-fueled boosters, and a single-engine Centaur upper stage—has been used relatively sparingly to date, having boosted NASA’s Curiosity rover toward Mars in November 2011 and, more recently, a pair of classified missions in April and December 2014. It is currently the second most powerful Atlas V in active operational service and carries the potential to deliver approximately 38,450 pounds (17,440 kg) into low-Earth orbit and up to 18,270 pounds (8,290 kg) to geostationary altitude.

The first stage consists of the 106.5-foot (32.4-meter) CCB, powered by a Russian-built RD-180 engine, with a total propulsive yield of 860,000 pounds (390,000 kg) at the instant of liftoff. The CCB was erected in the Vertical Integration Facility (VIF) at the SLC-41 site on 24 October, after which a quartet of side-mounted, solid-fueled boosters were installed around its circumference. Each booster stands 55.7 feet (17 meters) and enhances the 541’s lifting capacity. The boosters are jettisoned in pairs at about 110 seconds into the flight, after which the RD-180 will continue to burn for another 2.5 minutes. Following the shutdown of the first stage, the RL10C-1 engine of the restartable Centaur upper stage will execute no fewer than three “burns”—lasting eight minutes, six minutes, and about 90 seconds, respectively—to inject GOES-R into an orbit with an apogee of 21,925 miles (35,284 km) and a perigee of 5,032 miles (8,100 km), to kick off up to a decade of operational service.

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