Part 3 of 5
By Douglas Messier
The space shuttle Columbia glowed brightly as it streaked across the predawn skies of the western United States on Feb 1, 2003. Decelerating from an orbital speed of 28,165 km/hr (17,500 miles/hr) at an altitude of 70,165 m (230,200 ft), the shuttle and its seven crew members were enveloped in super heated plasma as they descended deeper into the thickening atmosphere on their return from a 16-day science mission.
Three observers on the ground who were filming the fiery reentry suddenly noticed something odd. There was a sudden flash on the orbiter, and then bright objects streaked behind the ship and burned up.
“Look at the chunks coming off that,” one shouted. “What the heck is that?”
“I don’t know,” his friend replied.
They didn’t realize it, but they were watching a doomed ship on its final voyage. The shuttle orbiter was shredding itself as gases as hot as 2,760°C (5,000°F) penetrated the vehicle through a hole in the left wing. The gap in the thermal protection system had been created when a piece of foam fell off the external tank and struck the shuttle during launch more than two weeks earlier.
As Columbia crossed over America’s western deserts, ground observers continued to witness bright flashes as more pieces were torn loose from the orbiter. Inside the cockpit, four fault messages appeared on the space shuttle’s instrument panel accompanied by audible tones.
“Feeling the heat,” Commander Rick Husband radioed to Mission Control in Houston.
Mission controllers saw sensors measuring conditions in the left wing and tire pressure in the left wheel well go offline one by one.
“Columbia, Houston,” the capsule communicator (capcom) radioed up. “We see your tire pressure messages and did not copy your last [message].
“And Houston, roger, bu –“ Husband replied, his message cut off in mid-sentence.
It was the last communication from the doomed ship. Five seconds later, Columbia lost all hydraulic power needed to control its flight surfaces. A master alarm sounded in the cockpit as the ship tumbled violently out of control.
Witnesses on the ground near Dallas witnessed the horrifying sight of the orbiter breaking up and pieces of it crashing to Earth. In Houston, the capcom continued to call up to the ship in an effort to reestablish communications until reports of debris falling north of them confirmed their worst fears.
“Lock the doors,” Flight Director LeRoy Cain ordered his team as a tear ran down his cheek. The move was part of contingency procedures designed to preserve all data from the mission.
Doomed From the Start?
There had been no escape for Husband, pilot William C. McCool, payload commander Michael P. Anderson, mission specialist David M. Brown, mission specialist Kalpana Chawla, mission specialist Laurel Clark and payload specialist Ilan Ramon, who was the first Israeli to fly in space.
The subsequent accident investigation discovered the same type of complacency about safety that had led to the destruction the space shuttle Challenger 17 years earlier. The external tanks had shed foam on previous flights, but all the orbiters had come home. The problem became an acceptable risk. So, when a piece of foam hit Columbia‘s wing, it was not deemed to be serious. Mission controllers turned down a request to have the U.S. military use its spy satellites to image the orbiter to check for damage.
Whether it would have made any difference is the great unanswered question of the Columbia disaster. The space shuttle Atlantis was in the advanced stages of preparation for launch. If the hole in the wing had been discovered early in the flight, if on-orbit supplies could have been stretched, and if Atlantis had been launched in time, the crew might have been saved. A successful rescue would have required a lot of things going exactly right in a very compressed period of time, but it was not impossible.
That such a damaging foam strike occurred on this particular flight was another haunting aspect of the tragedy. Unlike the majority of shuttle flights that docked with the International Space Station (ISS), Columbia flew a stand-alone science mission. Because of the particulars of the mission, it wasn’t even capable of reaching the station, which would have provided a safe haven while ground controllers figured out how to bring the crew home.
Echoes in Time
The sudden loss of a second space shuttle orbiter and its crew threw the American space program into a crisis. Not only did the accident destroy one-quarter of the space shuttle fleet, but it left the remaining three orbiters grounded indefinitely. Until they began flying again, the only access to the unfinished space station would be aboard Russian Soyuz spacecraft.
NASA’s leadership and the administration of George W. Bush faced a series of fundamental questions about the future of the shuttle program. What would it cost to get the shuttles flying again? How long would it take? Should they continue flying the three aging orbiters? And for what types of missions? Would it make sense to build a replacement orbiter? What exactly was NASA’s human spaceflight program for?
The questions were similar to those the German Zeppelin program had faced in 1937 after the loss of the Hindenburg. Although they were very different vehicles separated by decades of technological progress, German Zeppelins and American space shuttles shared a number of similarities.
Unique. Germany was the only nation still flying rigid airships when the Hindenburg exploded in May 1937. All other nations had stopped flying these vehicles years earlier after experiencing catastrophic accidents.
The Soviet Union’s copy of the U.S. space shuttle, Buran, flew once in space without a crew in 1988, making a single orbit before landing back on Earth. The program was soon abandoned as too costly as the Soviet Union began to collapse.
Enormous. The space shuttle was the size of a DC-9 jetliner, dwarfing the much smaller Russian Soyuz and Chinese Shenzhou spacecraft. The Hindenburg and Graf Zeppelin dwarfed airplanes of the day in size; they were longer than some contemporary ocean liners.
Enormously Capable. The space shuttle could carry up to seven astronauts and payloads weighing as much as 24.5 metric tons (27 tons). It could stay in space for weeks and then land on a runway.
Russian and Chinese spacecraft are limited to three passengers and a minimal amount of cargo. They make ballistic reentries and land by parachute.
The Hindenburg could carry 72 passengers, 52 crew members and large amounts of cargo across the Atlantic Ocean from Germany to the Americas without refueling. The DC-3 could transport up to 28 passengers and three crew members on much shorter flights.
Expensive to Build. Zeppelins took about two years to build at a cost of millions of marks. The space shuttle Endeavour, which was built as a replacement for Challenger, took four years and cost $1.7 billion to construct. Unlike airplanes, these vehicles could not be easily rolled off assembly lines in large numbers.
Few in Number. The loss of Challenger and Columbia destroyed 40 percent of the space shuttle fleet. NASA build only five operational space shuttles, with a sixth (Enterprise) limited to atmospheric tests. The space agency never had more than four operational shuttles at any given time, and often had even fewer available.
The explosion of the Hindenburg destroyed half of the German passenger airship fleet. The remaining ship, the Graf Zeppelin, was decommissioned immediately after the tragedy at Lakehurst because it could not be easily converted from hydrogen to helium. Only one more Zeppelin was completed and flown before the program ended.
Costly to Fly. The Hindenburg required about 50 crew members to run the ship and care for up to 72 passengers. It’s not a ratio that compared very well with airplanes and ocean liners of the day. Ticket prices were subsequently quite high. Even with high ticket prices, a lot of the Zeppelin’s income came from hauling the mail between continents.
The Hindenburg and Graf Zeppelin were largely competing with ocean liners for high-income passengers eager to fly between Europe and the Americas. Zeppelin travel was a niche market for people willing to pay extra to get to their destinations faster.
The space shuttle had been designed with economy in mind. The goal was to make space travel affordable, routine and safe while flying a fleet of orbiters up to 50 times per year. All U.S. payloads would be launched aboard the orbiters.
However, NASA was never able to achieve the cost savings it envisioned. A small army of people was required to launch space shuttles and service them in between flights. Fifty flights per year turned out to be a mirage; the shuttles would launch only 135 times in 30 years.
The Challenger accident put an end to plans to phase out America’s fleet of expendable boosters for satellite launches. Meanwhile, the European Ariane booster scooped up commercial launch contracts, and the Russians made their boosters available on the international market after the breakup of the Soviet Union.
Government Dependent. The United States fully funded the space shuttle program, using it for exploration, science and national prestige. Adolf Hitler’s Nazi government rescued the Zeppelin Company from bankruptcy during the Great Depression because it saw the propaganda value of its airships.
Dead Ends. It’s difficult to know precisely how Zeppelins might have developed had the Germans obtained the helium they needed to fly them in a safer manner. Perhaps they might have become larger and more capable.
However, the chances are high that the ships wouldn’t have progressed much further. The technology of the day might not have scaled up much larger.
Technology development also requires a lot of money. The 11 million German marks that Hitler’s government put into the Zeppelin Company were a fraction of the funds it was spending on aircraft, tanks, buzz bombs and ballistic missiles. Airplanes, not Zeppelins, were the wave of the future in 1937.
By 2003, NASA was flying an aging fleet of complex vehicles designed using 1970’s technology. Maintaining, upgrading and certifying them for flight was becoming increasingly expensive.
Although the shuttles were very versatile and capable of doing things that no other human spacecraft could do, they also cost NASA about $3 billion per year to operate regardless of how many missions were conducted. And now two of them had suffered catastrophic failures. Each failure left the rest of the fleet grounded for about 2.5 years.
As American space officials considered their options in the wake of the Columbia accident, there was no serious consideration given to building a larger, more capable space shuttle to replace the current fleet. The technology just didn’t scale up very well. Instead, NASA would decide that smaller was better.
A New Vision Takes Shape…
In the same way the explosion of the Hindenburg marked the beginning of the end of the German airship effort, the loss of Columbia began a similar progress for the American shuttle program. Zeppelin passenger service was halted immediately; the last German airship flew for the final time two years after the tragedy at Lakehurst. Ending the shuttle program would take 8.5 years, or six years after the remaining orbiters returned to flight.
Rethinking the civilian space program, the Bush Administration launched the Vision for Space Exploration, a program focused on sending astronauts back to the moon and beyond. The program had several new elements.
NASA would develop a new crew vehicle called Orion that would serve both the space station and fly to the moon. Two new Ares launch vehicles would be developed, one for orbital flights and a larger heavy-lift booster for lunar voyages.
NASA also decided that crew and cargo would be largely separated instead of being combined as they were on the space shuttle. The space agency contracted with SpaceX to develop the automated Dragon ISS resupply ship and the Falcon 9 booster to launch it. Orbital Science Corporation (now Orbital ATK) won a contract to develop the Cygnus cargo ship and the Antares launch vehicle.
This exploration architecture would be altered after the Obama Administration took office in 2009. Orion would be limited to carrying astronauts beyond low Earth orbit. Trips to the moon were canceled in favor of an asteroid retrieval mission and an eventual Mars mission.
The smaller Ares I booster intended for Orion trips into orbit was canceled. And Ares V heavy-lift launch vehicle rocket was also canceled, although it later morphed into the heavy-lift Space Launch System.
In place of Orion for trips to the space station, NASA embarked upon the Commercial Crew Program. Boeing won a contract to develop its CST-100 Starliner, which will be launch aboard a modified Atlas V booster. SpaceX is developing a Crew Dragon spacecraft that will launch on the Falcon 9.
These programs marked a return to the past for NASA. Orion, Starliner and Dragon are much smaller vehicles that incorporate capsules with heat shields that will land under parachutes, in much the same way as the Mercury, Gemini and Apollo spacecraft did. Unlike those earlier expendable capsules, the Dragon and Starliner spacecraft are designed for multiple reuses.
The only hint of a shuttle-type vehicle remaining in the U.S. civilian space inventory is the Dream Chaser, a lifting body spacecraft that Sierra Nevada Corporation is developing for NASA’s ISS resupply program. The vehicle is a fraction of the size of the space shuttle. Dream Chaser had been part of NASA’s Commercial Crew Program, but it was eliminated for the final round.
…but, in the Meantime
Developing new spacecraft and boosters would take time and money. Much more time and money than anyone anticipated; nearly 15 years after the loss of Columbia, Orion has flown to space once without astronauts and the two commercial crew vehicles have remained Earth bound due to repeated delays caused by under-funding and technical challenges.
While new systems were being developed, the space shuttles still had a major role to play in completing construction of and supplying the space station. After a stand down of 2.5 years for a series of upgrades to the shuttles and external tanks, Discovery roared off the launch pad at Cape Canaveral on July 26, 2005, on a much needed resupply mission to the ISS.
Discovery and her sister ships, Atlantis and Endeavour, would fly 20 additional missions to the station over the next six years, in the process completing the facility’s construction, rotating crew members, and stocking it with equipment, supplies and spare parts.
These flights were conducted under the principle of using the station as a safe haven in case a shuttle was damaged during launch. ISS astronauts could inspect the orbiters for damage as they approached the station to dock. The shuttles also carried repair kits for the thermal protection system if the damage was not too severe.
Atlantis made the only flight during the final 22 missions that did not visit ISS. During a 13-day mission in May 2009, astronauts serviced the Hubble Space Telescope for the fifth and final time. Despite the additional risks, space agency officials decided the venerable 19-year old telescope was worth it. No other crewed or robotic vehicle was capable of servicing the spacecraft.
A Bittersweet End
Atlantis also flew the final space shuttle mission, which was launched on July 8, 2011. When the vehicle rolled to a stop with its four-member crew 13 days later at NASA’s Kennedy Space Center, the space shuttle era came to a bittersweet end after 30 years and 135 flights.
The end of the space shuttle program left a big gap in American space transportation. Although American cargo delivery flights to ISS resumed in October 2012 with the first flight of SpaceX’s Dragon resupply ship, neither it nor Orbital’s Cygnus spacecraft could replace the shuttle’s enormous capabilities.
The U.S. space agency has been forced to rely on Russian Soyuz spacecraft for access to the space station due to delays in the commercial crew program. As a result, the crew size on the orbiting laboratory has been limited six instead of seven, reducing the amount of research that can be done on board. This reliance will not be remedied until the end of next year at the earliest.
By contrast, the end of the German airship program had a minimal impact on the overall transportation system of its day. Airplanes were already making transatlantic flight between Europe and America. Ocean liners could carry far more people with much lower fares. There were other ways to ship mail. The disappearance of a small fleet of Zeppelins that carried the rich and a lot of mail caused barely a blip in the market.
The era of the rigid airship is a largely forgotten period in early passenger aviation, a niche in time during which enormous ships flew through the skies and then suddenly disappeared like the prehistoric dinosaurs.
To the extent most people know anything about rigid airships today, they know that the Hindenburg exploded over New Jersey and that a picture of that tragedy adorns a classic rock album cover. They also probably marvel that passengers would have ever boarded a ship with that much flammable hydrogen aboard.
Like the Graf Zeppelin before them, the three remaining flight shuttles — Atlantis, Discovery and Endeavour — became museum attractions. As memories of the shuttle era fade away and smaller crew capsules begin flying, there will be museum goers who will gaze up at the shuttles and marvel, “Can you imagine? People actually flew into space on these things. Amazing!”