“The great bird will take its first flight upon the back of the great swan, filling the world with wonder and all writings with renown, and bringing eternal glory to the nest where it was born.”
Chapter 5: Countdown
The passing of the thunderstorms brought a renewed storm of activity at Kennedy Space Center. With the arrival of the Space Transportation System stack back at the pad, the deferred work of preparing the system for flight could resume. The process of preparing a mission for flight was not as simple as “gas-and-go”. Rather, it was a series of steps to prepare the vehicles and carefully check the final systems to prepare for flight over the course of days. Three days before launch, pad technicians stowed and locked down the crew’s in-flight equipment. Checklists, ration packs, and spare navigation equipment were loaded into under-floor storage boxes and secured shut. Two days before launch, ready supplies of various fluids were pumped into tanks on the Launch Umbilical Tower: hydrogen and oxygen for the orbiter’s fuel cells, hydrogen peroxide for the Lifter’s thrusters and APUs, and supercritical helium supplies for the Orbiter’s pressure-fed rocket engines. With that done, the pad technicians, dismissed during that dangerous phase of preparation, returned to continue their work. Analog switches and dials were checked and re-checked, to ensure they were in the proper position--it would not do to have a throttle valve open during tanking. The digital computer’s software was checked one last time, and found good. Inert mass simulators were loaded into bays and seats that, in an operational flight, would carry mission specialists or experiments. A day before launch, the fuel cell valves were opened, and the Orbiter began running on its own power. The Orbiter and Launch Control both sent radio signals to Houston, where Mission Control at Johnson Space Center verified that it could communicate with the vehicle. The mobile clean room provided 200 feet above the ground by the Mobile Service Structure retracted, and the MSS itself rolled back to a safe distance down the crawlerway.
As the launch approached, preparation milestones were met in quicker and quicker succession, just as a rocket accelerates at an ever-growing rate as its propellant is burned. At T-9 Hours, the air conditioning system in the launch vehicle’s unmanned sections switched to gaseous nitrogen from air. The propellant tanks were purged of gaseous oxygen, to eliminate the risk of fire. At T-8 Hours, rocket-grade kerosene began to be pumped into the lowermost tank of the stack, tripling the stack’s mass in just a half hour. At T-7 Hours, 28 minutes, liquid oxygen was slowly introduced into the upper stage propellant tank, flashing initially to vapor as it hit the walls, but carrying off some of the aluminum tanks’ latent heat. Soon, the tanks were cool enough for liquid oxygen to begin accumulating--a process completed within 45 minutes. At T-6 Hours, 27 minutes, the process repeated in the Booster’s LOX tank. At T-4 Hours, 11 minutes, liquid hydrogen poured into the much larger tank above the upper stage’s LOX tank, a process which wouldn’t stop before the final moments of the countdown--the hard cryogenic fluid boiled without stopping, requiring constant top-off. At T-3 hours, the Space Shuttle stack was, but for the order to fire, a live vehicle. Between the loads of the propellant pushing down on the pad, the expansion and contraction of the aluminum under varying thermal loads, the thick condensation clouds emanating from the cryogenic tanks, and even a subtle swaying in the wind, one could be forgiven for taking that literally.
As propellant was loading, the four crewmen who would fly the two vehicles through their first joint mission received their briefings. The Booster’s crewmen, veteran John Young and rookie Bob Crippen, had the lower-pressure job--their colleagues in the Booster Pilot group had already put Constitution through her paces. That didn’t reduce their dedication to the task one iota. The Orbiter’s crew, Fred Haise and Richard Truly, had the eyes of the entire agency on them. The pressure had little more effect on their efficiency than it did on the Booster crew. Weather looked good that day, at the Cape and at the abort landing strips in California and New Mexico. The storms that had passed through last week brought a cold front, with high pressures and a clear, blue atmosphere in their wake, and temperatures balmy enough for Haise to joke that he wished the astronaut transfer van were a convertible. As the crews suited up (wearing brown ejection suits, considerably less constricting than the sealed white A7Ls Haise and Young had worn to the Moon), technicians passed on wishes of good fortune and grabbed last-minute handshakes. Smiling and waving, despite Nixon’s goals of routine, ordinary spaceflight, remained part of the astronauts’ job description.
The four crewmen and a small team of technicians ascended the LC-39A lift. They stopped half-way up, Young and Crippen stepping out to take command of the Booster, Haise and Truly then continuing to their own ship. In parallel, technicians strapped them down into upward-facing seats, awkwardly fitting through a hatch 90-degrees off from its proper orientation. As the last two hours before launch elapsed, Young and Crippen glanced up at the tapering shape of the Shuttle stack, culminating in the irregular tip that was the Orbiter, in between going over their own last pre-flight checks. The Saturn V and its predecessors had tapered to a point. The Shuttle tapered, too, but then bulged outward again to accommodate the Orbiter’s control surfaces. It was a view equally familiar and alien--when flying airplanes, each of them had been able to see the nose in front of them while they sat in the cockpit, but here it was rotated vertically and yet with no sense of motion. It differed as much from ordinary airplane flight as it did from the old Apollo days, when the crew would be cut-off from sunlight entirely by the Boost Protection Cover of the capsule.
T-2 Hours. All crew members were strapped in. Technicians gave them a last thumbs-up before sealing the hatches on each vehicle, and left them to their own devices. Haise cracked a few jokes with Truly--”It’s not supposed to rain in Houston this week. Think we can get John and Bob to water our grass?”
The next hour and a half was almost peaceful for the astronauts, little to do but verify that their radios worked every few minutes. Similarly, for the pad technicians, there was little more they could do to influence the mission. All came down now to the men monitoring telemetry at Launch Control and Mission Control, who could yet call a halt at any moment. In the last few minutes, the stack shuddered as its two main stages pressurized and the engines were purged with helium. The huddled lines of flight controllers bent over their consoles, watching their telemetry as the mission-critical events streamed by.
In the last few minutes, the stack shuddered as its two main stages pressurized and the engines were purged with helium. The huddled lines of flight controllers bent over their consoles, watching their telemetry as the mission-critical events streamed by. A crowd of three-quarters of a million onlookers gathered at the viewing sites. As they listened, the public affairs officer recounted events as the clock wound rapidly towards zero.
The testing of the second stage thrust vector control was a whining noise above Haise and Truly's heads. Back in Houston, an engineer nodded assent to the Flight Director. TVC go.
With three minutes left to go, the auxiliary power units on the booster and orbiter whined to life within the stack. Dials jumped for a moment then settled in the stack's cockpits. Another nod from a flight controller followed as the telemetry streamed back to their consoles. Vehicle on internal power.
One minute left. Haise and Truly watched above them as the orbiter tested its hydraulics, flexing its rudder and elevons. There was a distant hydraulic whine as Constitution tested her own control surfaces: rudders, elevons. The doors covering her jet intakes flexed open, then closed again. Distantly, another controller confirmed it. Hydraulics go, all flight controls nominal.
Thirty seconds left. The final service arms retracted, leaving the vehicle standing alone. A flight controller smiled tensely as the hydrogen levels inside the interstage stayed right down the middle as the tanks came up to pressure. Tank pressure go.
The final seconds ticked down as the commentator counted events off. Fifteen seconds. Ten seconds. Nine. Eight. Seven. Six. Main engines start. A rush of fire spun up the F-1B turbopumps. RP-1 and LOX poured into the combustion chambers at phenomenal rates. Mixing, they sparked and ignited. Hot gas poured out the throat far faster than the speed of sound. A flash of flame billowed up around the vehicle, then was sucked down the flame trench by the speed of the exhaust flow leaving behind a cloud of smoke lit from below.
Five. Four. All engines on. Bolts on the hold-down arms absorbed the load. Now they weren't holding the massive bulk up, they were tethering it down as it pushed for the sky. Three. Two. One. Controllers waited for the computer's final decision. The rest of the world held their breath for the next word from the launch announcer...
As the final years of the 1970s wound down, NASA found itself once more in a race to debut a new system to accomplish something revolutionary in spaceflight. However, unlike the widely-followed missions leading up to Apollo, the debut of the Space Transportation System was not a matter of great international stakes, nor was the deadline one set by a grand vision. The clock which was winding down was not one driven by public attention and international press, but by schedule overruns adding up and budgets running low. However, if the stakes were lower, the challenges were no less intense--and with the end of Apollo and the aerospace recession, the number of empty offices, smaller budgets, and generally lower public engagement only exacerbated the situation.
In spite of this, the Space Lifter portion of the Space Transportation System was largely on track, regularly marking items off the the program’s Gantt charts. The abort tests were complete, the first orbital launch of a demonstration payload had been carried out, and the third booster, RS-IC-603
Intrepid, was in the final stages of assembly at Boeing Field in Washington. Not everything was on track: the final assembly of RS-IC-604 and the planned order for RS-IC-605 were being delayed as a cost-saving measure to divert funds from the Space Lifter to the cost overruns being encountered on the Space Shuttle orbiter. Still, for the most part, the Space Lifter remained on track, ready for the STS-1 first operational flight in March of 1979. The Space Shuttle program as not as fortunate.
The Space Shuttle program had lagged behind the Space Lifter from the beginning, with a ten month difference between the award of the booster contract to Boeing and the award of the Space Shuttle contract to North American Rockwell. The debates over configuration, thermal protection systems, and more had driven the program to the ragged edge where it seemed as though the Space Lifter might become the only surviving element of the Space Transportation System. As the decade wound on, this became a theme in the Space Shuttle program. While the Lifter began its development rapidly following the contract award, building on almost a decade of studies in reusable winged S-IC stages, the Space Shuttle orbiter had to cut a new path. Even drawing on histories of lifting body studies by NASA and North American Rockwell’s Martin partner on the project, wind tunnel tests and computer simulations were needed to verify where the orbiter might expect to see peak heating during atmospheric return, determining which portions of the all-important Thermal Protection System could be thermal blankets, which could use high-temperature ceramic tiles, and which would be forced to use new reinforced carbon-carbon composites. Even while this work was ongoing, hundreds of engineers were beginning the process of laying down plans for the structural design of the vehicle, its orbital maneuvering systems, its payload bay doors and thermal radiators, its power systems and avionics, and the interior design of its crew spaces. All of these had been addressed by NAR’s original bid submission, but building the actual vehicle would require a higher level of detail.
The result was that while the first flight-ready booster rolled off the assembly line in the middle of 1976, the first Space Shuttle analogue suitable for even glide testing didn’t make its appearance until almost a year later, when OV-101
Pathfinder rolled out of Rockwell’s Palmdale assembly plant. Unlike the RS-IC, which could ferry itself around the country with its jet engines, the Space Shuttle required assistance getting airborne.
Pathfinder made her first flight in a captive carry on the back of a modified 747 at Edwards Air Force Base in November of 1977, This was the start of a year-long “Approach and Landing Test” series. The prototype orbiter took to the sky again and again on the back of its carrier, first with a set of five flights with the orbiter just an unpowered parasite on the back of the 747, then three more “captive-active” flights where, for the first time, the orbiter flew powered and with a crew onboard though it never left the back of its carrier. Finally, in September of 1978, the first free flight of the orbiter took place, With Fred Haise at the controls,
Pathfinder glided free and clear as the 747 carrier dived away from beneath her, then the Shuttle came in for a center-line landing on Edward’s main runway. It was a major step forward for the troubled program, but while the flight and the three additional flights that followed proved that the Space Shuttle would be able to glide and land after a flight to space, the program still faced issues with the systems involved in an orbital flight.
Even as
Pathfinder was making her flight debut, issues were surfacing in other areas of the program which put the final assembly of the first orbit-capable vehicle behind schedule. The two biggest problems developed with the design and testing of the orbiter’s launch abort system and the orbiter’s all-important heat shield. In order to boost a fully-loaded 26 ton orbiter and a 8-ton payload clear of the failure of a Space Lifter, more than seven metric tons of propellant otherwise earmarked for orbital maneuvering would have to be burnt in less than seven seconds. This would require a set of sea-level optimized high-thrust abort engines. In the end, the proposed system was four LR-91 engines fitted with a sea-level-optimized nozzle, with a single vacuum-optimized AJ-10 placed on the centerline of the vehicle for orbital maneuvering. The use of a pump-fed engine for this critical role was a major question mark in the Shuttle’s design phase. Reducing the risk was key. Though the LR-91 was already human-rated for use in the Titan GLV second stage, an extensive series of trials were carried out to verify that the designed cluster could be activated in time reliably, with more than a dozen firings of an integrated engine cluster made on a specially-built test stand at Edwards. Finally, however, the testing was completed.
While the tests of how the Shuttle would be lifted into orbit and escape disasters were complete, the problem of how the vehicle would make its return was still up in the air. The high-tech silica tiles of the Shuttle were revolutionary, offering the same thermal resistance of a metal hot-structure while divorcing the exotic materials of the TPS from the underlying traditional aluminum airframe. The selection of tiles over a metallic hot structure had been a key point of debate in the leadup to the Space Shuttle, but the wisdom of the selection was proven as the development of the airframe was able to proceed while tile production and testing was still ongoing. Tile development was initially trouble-free, but 1975 tests intended to look at the potential effects on the orbiter of losing tiles in flight revealed a potentially critical issue. These tests involved the use of a new arcjet-equipped vacuum chambers at Johnson Space Center to test the effects of entry-force heat and pressure on test articles the vacuum environment inside the ARMSEF. Initial assumptions had held that the airflow around the orbiter would be largely in line with the skin, and that holding up under 2 psi of force attempting to pull tiles loose would be sufficient. Unfortunately, this assumption would be proven wrong from two ends in 1975. The ARMSEF tests revealed that the tiles would need to withstand far higher forces to stay attached during entry--and that the current tile adhesives were not up to the challenge. Internal testing at Rockwell on early production samples around the same time showed similar results, but were initially attributed to early production quality-control issues. Tight budgets had restricted follow-on testing. However, with two tests coming to the same conclusion at the same time, NASA was forced to evaluate the existence of a more serious concern. Almost all of 1975 and much of 1976 was spent in tests to establish how bad the problem truly was. Re-analyzing the flight assumptions using the latest Computational Fluid Dynamics models and wind tunnel testing confirmed what ARMSEF testing had indicated: the tiles needed dramatically higher adhesion than had been originally called for. Moreover, Rockwell’s tests were repeated on tiles pulled from those intended for assembly of OV-102
Endeavour, which showed the same excessive variation in bond strength as the original test batches.
While the Space Shuttle program had known from the beginning that they would have to fight to make the planned launch date, ongoing development raised new problems. In 1976 with less than two years before the planned first flight of the Space Transportation Systems, it now looked like even if NASA could prove the orbiter could glide and that it could abort safely and maneuver in space, it might not be able to survive returning to Earth. Fortunately, a new solution was found to “densify” the tile cement using fine silica grains stabilized with ammonia. The revised densification was begun, but as it proceeded, it revealed further issues with variable bond strength. Worse, the tools to evaluate tile strength also proved troublesome: in order to test tiles before flight, non-destructive testing of tiles was planned using an ultrasound system. During initial tests of the system on the newly densified tiles as they were installed onto
Endeavour in 1977, the system proved temperamental. Tuned to avoid missing any “false negative” tiles which might actually be defective, it instead threw “false positives” for one tile in every ten. Actual testing, however, revealed that only one tile in a hundred was really defective. The result was that the process of cladding OV-102 in her protective mantle of tiles extended well beyond the end of 1977. Even as OV-101 was testing the Orbiter’s performance in the craft’s maiden glides, OV-102 was still more than a year behind the original delivery schedule. Arrival of the first Space Shuttle orbiter at Cape Canaveral was now expected no sooner than 1980.
While the Space Shuttle was struggling on the path to flight, the Space Lifter was proceeding through its final testing. The decision of desperation in 1971 to split the Space Transportation System into a Lifter and a Shuttle now began to acquire an air of quiet brilliance as issues with the Space Shuttle pushed its debut out even as the Lifter was cleared for flight. Originally, it had been hoped to debut both vehicles together, inaugurating the Space Transportation System with a manned mission. This would both symbolically end the gap in manned spaceflight since Apollo-Soyuz in 1975, as well as cementing Lifter and Shuttle as part of the indivisible STS in the eyes of the public. However, while a slip of a month or two to wait for the Shuttle might have been acceptable, the Space Lifter was ready for its first operational launch in early 1979. It had already spent the year since its first dummy launch profile in 1978 testing increasingly unlikely abort scenarios--further delays might bring the entire program’s funding into questions. While the Shuttle engineers worked to fix their issues with the tiles and accelerate
Endeavour’s preparations for delivery, the Lifter proceeded to the pad for the first time with a real payload on top.
STS-1 lifted off on March 23rd, 1979, with Joe Engle and Gordon Fullerton at the controls of the booster
Constitution. Strapped to the top of the S-IVC was an internal NASA payload, the communications satellite TDRS-A, the first of the new NASA Tracking and Data Relay Satellite System. Once deployed to geostationary orbit, the TDRSS constellation was intended to facilitate communications not between locations on Earth, but between Earth and orbiting Space Shuttles without the requirement for the global network of scattered ground stations used during the Gemini and Apollo era. TDRS-A was not only a major step for enabling the Space Shuttle program, however--it was also an important proving ground for the commercial viability of Space Lifter. The launch of an unmanned spacecraft to geostationary orbit on STS-1 would be the final proof of Space Lifter’s ability to do the same for future commercial missions. Flying the Space Lifter to geostationary orbit without a third stage was not particularly efficient--its payload dropped by three quarters, from more than forty metric tons to only ten. Even so, the Space Lifter was capable of lifting far more than the two tons of TDRS-A. The STS-1 mission demonstrated the first of many solutions to the excess capacity problem during a picture-perfect ascent. After 23 minutes coasting through space after primary ascent, the S-IVC relit its engines for the geostationary transfer orbit (GTO) insertion burn. During this burn, the S-IVC pushed TDRS-A onto a trajectory with a much higher apogee than standard GTO--a so-called “super-synchronous transfer orbit”--while also eliminating a larger portion of the orbit’s original 28.5 degree inclination. These maneuvers, more demanding of the second stage’s performance, used up some of the margin of the Space Lifter stack to leave TDRS-A closer to its final geostationary orbit than if it had flown on a traditional launch vehicle.
The next mission was scheduled four months later, following final evaluation of detailed performance data from the STS-1 mission. Launching for STS-2 on July 29, 1979, the booster
Independence made her own operational debut, demonstrating another option for commercial geostationary orbit payloads hitching a ride on the Space Lifter. The mission carried not one but two TDRS satellites, TDRS-B and TDRS-C. The pair were contained within a special structure, the “Multiple Launch Adaptor,” which supported the TDRS-C spacecraft above the TDRS-B spacecraft, each with its own set of mating fixtures, power supplies, and other interfaces. Even with five metric tons of payload and the mass of the MLA, STS-2 still had enough payload margin to boost its twin payloads into a super-synchronous GTO. In its first two operational launches, the Space Lifter amply demonstrated the values which made it attractive to commercial launch customers.
Lifter’s third flight, STS-3, would once again test a capability enabled by the Space Lifter’s massive payload capacity--one with attraction both to NASA and to NASA partners. However, this time the partner customer was far less public. Observers watching the mission in the evening of November 17. 1979--the first night launch of the Space Lifter program--saw the glowing trail of the rocket’s trajectory head out nearly due east over the Atlantic, as on STS-1 and 2. However, shortly after
Constitution separated, with her retro-propulsion burn providing a second false star in the night sky, the S-IVC altered its heading to the north, cutting away from the equator to skirt the coast of Newfoundland in a massive “dog-leg” trajectory. The maneuver was incredibly expensive in terms of delta-v: the steel payload simulator was barely more than the stack’s GTO capacity. However, the benefit was that it enabled the launch of a payload to a 98-degree sun-synchronous orbit from Cape Canaveral, instead of from the traditional American polar launch site at Vandenberg. With advocacy from Californian representatives in Congress, the US Air Force was converting the partially-completed Titan II launch site SLC-6 at Vandenberg into a site for the Space Lifter. This would enable the launch of full-payload missions including the Space Shuttle to polar orbit. However, the site was still several years from completion. In the meantime, the “dog-leg” would do for conventionally-sized payloads. Even with the massive inefficiencies of the dog-leg, Space Lifter could still match the payload of a Titan III rocket with slightly lower cost.
After STS-3, the Space Lifter had demonstrated its key operational mission modes for unmanned payloads, and was declared fully operational. Subsequent missions proceeded at a faster pace, and with less variation between flights. STS-4 in December 1979 followed just over a month after STS-3. As a holiday present to the agency, it saw the booster
Independence deliver two packages wrapped in the STS-MLA. The bottom payload was the fourth operational TDRS satellite, completing the initial constellation. The upper slot (with less risk of fouled deployment) was reserved for the Space Transportation System’s first commercial customer, the SBS-1 satellite. One of two HS-376-based satellites ordered by Satellite Business Systems from Hughes, it was the first of many other HS-376 busses which would fly on the STS. The Space Lifter would fly two more such missions during the first half of 1980, with STS-5 in February and STS-6 in April. In June, the Space Lifter flew its first classified DoD payload on STS-7, the debut flight of RS-IC-603
Intrepid, the first booster whose construction was funded by the DoD. This was an operational duplicate of the “dog-leg” polar trajectory tested on STS-3, with the stack inserting a classified payload into sun-synchronous orbit. Officially classified for many years, the launch was later revealed to be the latest in the KH-9 series of satellites.
While the Space Lifter’s activities were vanishing into a haze of routine, the Space Shuttle was finally making visible progress. With the last rounds of fixes to the tiles completed in fall of 1979, OV-102
Endeavour rolled out from Rockwell’s Palmdale integration site for its first ferry flight to the Cape. Engineers breathed a sigh of relief when she arrived safely intact in Florida--the airflow of the ferry flight served as a validation of the test results in the wind tunnels on the tiles, and not a single one came loose. The arrival of the orbiter at Kennedy Space Center instantly absorbed the attention of press, visitors, and innumerable technicians and engineers. For more than six months after her arrival in November,
Endeavour waited in the Operations & Checkout Build at Kennedy as test engineers put her systems through their paces. With the tests complete (and the secrecy around the VAB payload processing areas relaxed following STS-7), OV-102 was rolled across the five miles to the VAB on June 24, 1980. The booster
Constitution was next in the rotation, and was rolled into the massive facility a week and a half later once the final pre-stack checks were completed on the Shuttle. With Space Lifter’s maiden orbital test mission two years in the past, tourism at the Cape and national press attention had been slipping. The arrival of Space Shuttle
Endeavour for the debut of the manned STS was a shot in the arm. Hundreds of tourists a day watched as the booster was lifted to vertical and mated to the MLP, then joined by the S-IVC stage. Finally, eight years after the approval of the program, the Space Shuttle
Endeavour was grabbed in turn, lifted off the transfer aisle floor, and mated to the top of the Space Lifter stack. The STS-8 stack was complete. Rollout to the pad followed on July 15, 1980.
Simply completing the assembly, however, wasn’t the sole issue for the mission. STS-8 proved that while the full STS was ready for its debut, space launch operations were still anything but routine. During fill testing of the stack at the pad following rollout, a buildup of hydrogen gas was measured in the interstage between the S-IVC and the booster’s nose. Work stopped overnight. After waiting for the tanks to empty and vent clear, McDonnell-Douglas engineers and technicians entered the interstage from access gantries, and opened every panel they could. With the quick and dedicated work, and no shortage of good luck, the issue was found to lie in a non-critical bleed valve which could be replaced and tested on the pad. After careful approval, it was. The entire resolution had taken only a day. Remaining pad tests proceeded smoothly and hopes rose that the mission might go off on schedule. Unfortunately, storm clouds were on the horizon in the most literal sense--a tropical storm in the Caribbean had turned north and threatened the Florida coast with a hurricane. With worries about the security of the Shuttle’s tiles still foremost in everyone’s mind, the decision was made to roll the stack back to the VAB for safety. It proved unnecessary, as the tropical storm collapsed into only heavy thunderstorms instead of intensifying, but as several lightning strikes were recorded on KSC grounds, program managers agreed it had been the correct call.
The passing of the front and the return of the stack to the pad on July 21 kicked preparations to flight into high gear. The stack seemed no worse for the wear of two rollouts, and all systems passed inspection over the next few days. The Flight Director gave the traditional call to stations on July 24, and the final two-day launch campaign began. Closeout began on the orbiter and booster cockpits, onboard consumables of both vehicles were topped off and sealed, and the flight crew finished their final simulations. For the debut mission, NASA had assigned its most experienced Space Shuttle crew, Fred Haise and Richard Truly. Haise and Truly had been among the pilots who had trained for Shuttle flights during the Approach and Landing Tests, and indeed had flown together on OV-101’s maiden glide flight almost two years before. Now, they were assigned the task of taking
Endeavour to space. The pair took the attention in stride, focused on the tasks at hand.
The storms left behind a cold front, July 26th brought predictions of clear and sunny weather. The scheduled Saturday flight brought an audience from around the country to Cape Canaveral to witness the launch. Almost three-quarters of a million people followed along in the countdown, circulating around the visitor's center and viewing sites. They began to gather in the stands. Visitors chattered as they listened to the voice of the public affairs commentator run down the increasingly routine steps of preparing the vehicle: propellant filling on the booster and second stage, pressurization of the tanks, the arrival of the crew at the launch pad, the sealing of the Shuttle and Lifter cockpits and the retraction of the white rooms. In the launch control and mission control rooms, the attitude was just as tense. As the vehicle came to life in the final computer-controlled sequence, flight controllers were focused on the data streaming across their consoles.
The auxiliary power units whined to life. Flight controls twitched as they were tested. As the final umbilical arms retracted, the tank boil-off stopped and pressures rose to flight levels inside the tanks. Seconds later, a dense cloud of spray shrouded the surfaces of the mobile utility tower and covered the entrance of the flame trench. Main engine start with six seconds left sent a roar across the Florida swamps to the viewing stands. The stack shuddered slightly as bolts held it down against the thrust driving that wave of sound.
Constitution wanted to fly. In the final instant, the computers of the stack made their analysis. All engines running. All systems go. As an electric signal from the stack triggered the explosive bolts to release the hold-downs, the launch announcer's voice carried to the waiting crowd a single ecstatic word:
"...Liftoff!"
Authors' Note:
We hope that you've enjoyed Part I: Pre-Flight of Right Side Up: A History of the Space Transportation System! Part II will go up after a 3-week hiatus, but in the mean time, we've got pictures of the Lifter, Orbiter, and S-IVC that will start going up in the next few days! Stay tuned!
