Twenty years ago, last May, NASA’s youngest Space Shuttle speared for the heavens on her maiden voyage, STS-49. Orbiter Vehicle-105 (OV-105), named ‘Endeavour’ in a competition opened to thousands of US schoolchildren, had been built in response to the loss of her sister ship, Challenger, from a set of structural spare parts and would enjoy 25 missions into the heavens and a glorious career which would feature satellite deployment and retrieval – including that of the iconic Hubble Space Telescope – together with science, technology and space station operations. Truly, Endeavour would live up to the Shuttle’s original mandate: shuttling between Earth and low orbit to establish and maintain a near-permanent human presence off the planet. As NASA bids her farewell this well and prepares to despatch the infant of the Shuttle fleet to her retirement home at the California Science Center in Los Angeles, it seems fitting to pause for a few moments to reflect on Endeavour’s job well done.
The reader will recall from AmericaSpace’s article on STS-49 last week that Endeavour arose from a series of spare parts – a mid-fuselage, a forward-fuselage, wings, payload bay doors, to identify just a few – which had begun in April 1983 under a $389 million agreement with the Shuttle’s prime contractor, Rockwell International. The intent was that if major structural damage was suffered by any member of the four-strong fleet of vehicles, Columbia, Challenger, Discovery or Atlantis, the parts could be used either for repairs or perhaps to assemble a whole new craft. Three years later, the destruction of Challenger during ascent provided the tragic catalyst for a metamorphosis into OV-105. Authorised by Congress in July 1987, Endeavour was built within three years…and her first flight, in May 1992, yielded precisely the kind of attitude that would be expected from a new kid on the block. All Shuttle maiden voyages were exciting, it was true, but Endeavour’s was something different: the emphasis was not overwhelmingly on checking out the new orbiter’s systems…but upon hitting the ground running by executing one of the most ambitious missions in the post-Challenger era.
STS-49 was tasked with the retrieval, repair and redeployment of Intelsat 603 satellite, a critical telecommunications platform which was destined to provide coverage of the 1992 Summer Olympics in Barcelona. Its Commercial Titan launch vehicle had failed to properly insert it into a 22,600-mile geosynchronous and instead left it lingering in low-Earth orbit. Under a $90 million contract between the satellite’s manufacturer, Hughes, and NASA, the giant Intelsat would be brought into Endeavour’s payload bay, whereupon a new rocket motor would be fitted by spacewalkers Pierre Thuot and Rick Hieb and it would be reboosted into geosynchronous altitude. The early part of the mission did not go well. Although the rendezvous was successfully completed, two back-to-back EVAs failed to install a capture bar and physically seize the satellite, forcing some radical thinking: in the world’s first-ever (and so far only) three-man EVA, astronauts Thuot, Hieb and Tom Akers ventured outside together to manually grab Intelsat and bring it into Endeavour’s payload bay. It was a remarkable success and a remarkable example of NASA’s can-do spirit. The mission concluded with a record-breaking fourth EVA, in which Akers and astronaut Kathy Thornton rehearsed Space Station Freedom construction techniques, and a landing which showcased the Shuttle’s new drag chute.
Four months later, in September 1992, on STS-47, Endeavour roared aloft a second time, carrying the Japanese Spacelab, dedicated to life sciences and materials research in the strange microgravity environment. Amongst the crew was the first black female astronaut, Mae Jemison, and Japan’s first professional spacefarer, Mamoru Mohri, together with the first married couple ever to journey into orbit together, Mark Lee and Jan Davis. With STS-47, Endeavour highlighted – and would continue to do so, throughout her stories career – that she intended to set records and continue to break them. Another four months elapsed before she flew STS-54 in January 1993, launching a Tracking and Data Relay Satellite and featuring a dramatic, last-minute EVA by Greg Harbaugh and Mario Runco. It had long been recognised that as the Space Station era approached, more EVA experience was acutely necessary and both STS-54 and Endeavour’s next two missions, STS-57 and STS-61, would truly push the envelope.
The first of those missions, STS-57 in June 1993, already promised to be exciting, ahead of launch, since it marked the debut of the first commercial Spacehab science module and the retrieval of Europe’s EURECA free-flying satellite. When an EVA by astronauts David Low and Jeff Wisoff was added, it intensified the drama. Yet that EVA was itself enhanced when one of EURECA’s antennas failed to properly latch into place and needed a helping hand from the spacewalkers. More helping hands were needed in December, when the crew of STS-61 supported no fewer than five EVAs – a new Shuttle record, equalled, but never surpassed – to triumphantly service and install corrective optics on the Hubble Space Telescope. (A two-part commemorative article on the Hubble repair was recently published on the AmericaSpace site.)
Following the high drama of her 1993 missions, Endeavour transitioned to the role of a pathfinding science platform in 1994, supporting a pair of Space Radar Laboratory missions (STS-59 and STS-68) in April and September to map Earth’s surface in unprecedented detail using a powerful synthetic aperture radar in the payload bay. Her longest voyage of all, STS-67, followed in March 1995, when she flew her first and only Extended Duration Orbiter (EDO) mission, lasting almost 17 days. It was a record length for the Shuttle programme and would kick off a 15-month period in which sister ship Columbia would not hold the record for the longest mission.
Three subsequent missions were marked by the fact that they deployed and retrieved satellites from orbit…and supported EVAs. STS-69 in September 1995 was the first ‘double’ deployment and ‘double’ retrieval mission, launching and picking up both the Wake Shield Facility and the Spartan satellites and staging another station-practice EVA by astronauts Jim Voss and Mike Gernhardt. Retrieval of Japan’s Space Flyer Unit in January 1996, and deployment and recovery of another Spartan free-flyer, devoted to technology research, and a pair of EVAs featuring three astronauts – Leroy Chiao, Dan Barry and Winston Scott – formed the basis of STS-72 and Endeavour’s 11th voyage, STS-77, in May of that year carried out four satellite deployments and operations with the commercial Spacehab facility.
After STS-77, Endeavour was extensively modified to support missions to Mir and the International Space Station. Her Extended Duration Orbiter provisions were removed and in January 1998 she flew STS-89, the penultimate docking flight to Mir, which exchanged astronaut Dave Wolf for Andy Thomas. Next came the epochal STS-88 in December, the first flight to transport US-built equipment into orbit for the assembly of the International Space Station. During 12 days in orbit, Endeavour’s crew rendezvoused and docked with the Russian-built Zarya control module and attached the Unity node. It was the beginning of a new era. Only one more ‘stand-alone’ mission would take place for Endeavour. In February 2000, she flew the Shuttle Radar Topography Mission, which used much of the Space Radar Laboratory hardware to map Earth’s surface, together with a long interferometry mast, which provided additional three-dimensionality to the resultant radar images.
Following STS-99, the remainder of Endeavour’s career would be exclusively devoted to construction and maintenance of the International Space Station. First, she brought power: in December 2000 her STS-97 crew installed the first set of port-side solar arrays, followed by Canada’s robotic arm in April 2001 on STS-100 and three logistics and crew exchange missions on STS-108 in December 2001, STS-111 in June 2002 and STS-113 in November 2002. The last of these flights was a particularly poignant, coming just weeks before the tragic loss of Columbia, which would bring the entire Shuttle fleet to its knees for more than two years.
Endeavour would remain grounded until August 2007, when (to an extent) she fulfilled her mandate as Challenger’s replacement by carrying the backup candidate to teacher Christa McAuliffe into orbit. Barbara Morgan had trained in McAuliffe’s shadow, all those years before, and had witnessed the disaster which tore out NASA’s heart in January 1986, before returning to teaching. However, space exploration continued to call Morgan and in August 1998 she was selected for NASA Mission Specialist training. Nine years later, on STS-118, she finally got her chance to fly.
Three 16-day missions followed, with STS-123 in March 2008 carrying the logistics module for Japan’s Kibo complex and Canada’s Dextre robotic ‘hand’ to the station, STS-126 in November 2008 carrying the first provisions for six-crew capability and STS-127 in July 2009 carrying the outside porch and equipment for Kibo. All three missions featured some of the most complex EVAs ever attempted. By the end of 2009, Endeavour had flown 23 times into space – more than twice as many as Challenger – and had only two more missions ahead of her. The STS-130 voyage in February 2010, whose crew included NASA’s current Chief Astronaut, Bob Behnken, delivered the Tranquillity node and the multiple-windowed cupola to the station, whilst her final mission, STS-134, in May 2011, attached the Alpha Magnetic Spectrometer onto the exterior of the near-complete international complex.
As Endeavour prepares for her cross-country journey from Florida to California, this week, it is hard not to feel sadness, for both she and her sisters matured substantially over their years of service. Although inherently dangerous and still capable of killing a crew on each and every mission, no matter how many safeguards were installed, Endeavour provided a reliable platform for 25 crews, 148 astronauts and cosmonauts – including representatives of Japan, Switzerland, Russia, Canada, Germany, Italy, France and the United States – and more than 296 days in orbit. She circled the globe more than 4,600 times and travelled 122 million miles. Her ‘endeavour’ into the unknown can be remembered not only from the roomfuls of scientific data from each of her missions, or the recollections of her many occupants…but from a bright star in the night sky which she helped build: the International Space Station. Perhaps this is Endeavour’s grandest and most enduring legacy.