One Small Step Page 24
TIMELINE
1985 6 June Soviet spacecraft Soyuz T-13 launches. Its mission is to attempt to dock with, and return to operational status, the “dead” space station Salyut 7
13 June Following earlier successful power restoration, Salyut 7’s attitude control system was reactivated, meaning that a Progress cargo craft could deliver new supplies
1986 19 February Soviet Mir space station is launched
5 May Cosmonauts begin a journey from Mir to Salyut 7—the first ever inter–space station flight
“Uh oh”
THE CHALLENGER DISASTER
STS-51L
1986
On January 28, 1986, the Space Shuttle Challenger, designated mission number STS-51L, blasted off from Cape Kennedy. For those watching, it appeared initially to be another exhilarating, yet almost routine, liftoff. Among the spacecraft’s mission tasks was the deployment of the second in a series of tracking and data relay satellites. Also on board Challenger was a teacher, Christa McAuliffe, who was there as part of the Teacher in Space Project. But just over a minute into the Shuttle’s flight, the unthinkable occurred.
In January 1986 Mike Mullane was in training for a secret military Shuttle mission to be launched from its alternative launch site at Vandenberg Air Force Base in California. He recalls:
I was with the rest of the STS-62, we were in training at Los Alamos Labs. One of our payloads was being developed at Los Alamos Labs, so we were up there at Los Alamos. We were in a facility that didn’t have easy access to a TV. We knew they were launching, and we wanted to watch it, and somebody finally got a television or we finally got to a room and they were able to finagle a way to get the television to work, and we watched the launch, and they dropped it away within probably 30 seconds of the launch, and we then started to turn back to our training. Somebody said: “Well, let’s see if they’re covering it further on one of the other channels,” and started flipping channels, and then flipped it to a channel and there was the explosion, and we knew right then that the crew was lost and that something terrible had happened.
Danger Signs
In the two years before the Challenger accident there had been 15 missions, 12 in the previous year alone. The Shuttle was beginning to do what it was meant to do—or rather what the PR said it should do—that is, become a regular “space truck,” routinely plying between the ground and low-Earth orbit. In April 1985 the Shuttles Discovery and Challenger were launched just 17 days apart. There were spacewalks, some nontethered satellite deployments for the Department of Defense and the commercial satellite retrievals and in-orbit repairs. The robot arm worked impressively. There were also myriad experiments performed on the mid-deck and in the payload bay. But the high flight rate was straining the system in terms of engineering manpower and spare parts. There were specific warning signs for those who knew how to recognize their significance.
Between Challenger’s fourth flight—the STS-41B mission in February 1984—and its final flight (its tenth) in January 1986, there were 15 successful Shuttle missions. In only three of those missions was there no visible damage to the SRB O-rings; in nine of the missions the burn-through was serious. One mission, 51C, was launched after a bitterly cold January night at Cape Kennedy. When the recovered SRBs were inspected, the O-rings were found to be severely damaged. The Shuttle fleet should have been grounded. Sooner or later its luck would run out.
Lucky Escapes
On the next flight, STS-51D, Discovery blew a tire and the brakes seized on landing due to a strong crosswind. For the time being landings at Cape Kennedy were halted. Three months and three Shuttle missions later, Challenger’s central SSME failed during ascent. Fortunately it was straightforward to “abort to orbit,” reaching a safe but slightly lower orbit than intended.
The mission prior to Challenger-61C (Columbia’s seventh voyage)—could also have been a disaster. A valve malfunction meant that one of the SSMEs could have exploded at main engine cut-off when the Shuttle reached orbit. The shower of debris from the explosion would have crippled the Shuttle, making it impossible to survive reentry. Fortunately, the launch was scrubbed for another reason and the fault found. But even that was not the only potentially fatal flaw. A faulty drain back valve from the external tank that could have killed the crew was also discovered.
Challenger at liftoff on mission STS-51L. The smoke seen at bottom right was the first visible sign that an SRB joint may have been breached.
A Ride to Death
As well as the crew of specialist astronauts, Challenger’s final flight also had a passenger: the schoolteacher Sharon Christa McAuliffe. (She was not the first passenger aboard a Shuttle, however: STS-41C also had a passenger on board—Congressman William Nelson, who was ostensibly a “payload specialist” but in reality was hitching a ride because of his influential political position. He was the second politician to fly on the Shuttle following Senator Jake Garn the previous April.)
Seventy-three seconds after liftoff Challenger exploded in a heartbeat just after Commander Dick Scobee gave the order: “Go at throttle up.” Shortly afterward pilot Mike Smith was heard to say: “Uh oh.” An O-ring in the right-hand SRB had failed, and flame was visible through the SRB wall. The damaged SRB then pulled away from the external tank, causing it to fragment. There were more than a million pounds of propellant in it when it detonated. Challenger disintegrated at 14,630 meters (48,000 ft.) but continued to climb to 18,288 meters (60,000 ft.). In fact, there was no explosion in the true sense. Although the dramatic and massive release of oxidizer and fuel gave that impression, the liquids were actually vaporizing and burning. Challenger disintegrated, but it seems the crew were not killed instantly.
Six weeks later NASA found the crew cockpit. Many had hoped that it would never be discovered, but since it was in relatively shallow water, sooner or later it would have been encountered by a diver or snagged on a fishing net. The cockpit section of Challenger was well built and survived the accident intact. It can be seen in still-frames training cables. For a few seconds the G-forces on the crew would have been intense—12 to 20 G—but then they would have swiftly fallen to about 4 G and then a few seconds after that down to zero G as the cabin would have been in free fall. There is evidence that some of the crew were conscious after break-up because three of the four personal egress air packs on the flight deck were turned on, and air consumed was consistent with breathing until impact with the sea. We do not know if the crew were conscious all the way to the impact. The air supply was unpressurized, so if the cabin had been breached they would, mercifully, have passed out within a few seconds. The cabin fell 19,812 meters (65,000 ft.) in 285 seconds before striking the ocean. It was this impact, at 210 miles per hour (338 km per hour), which killed the crew.
On the evening of the disaster President Reagan canceled the State of the Union speech for a week and gave a national address from the Oval Office. Written by speechwriter Peggy Noonan, it closed with a quote from the poem “High Flight” by John Gillespie Magee Jr.:
We will never forget them, nor the last time we saw them, as they prepared for their journey and waved goodbye and “slipped the surly bonds of Earth” to “touch the face of God.”
The subsequent Rogers Commission that looked into the cause of the accident discovered that engineers’ worries about the O-rings were not passed on to NASA managers at HQ in Washington, the astronauts in Houston or the launch director at Cape Canaveral on that fateful day. Afterward one astronaut said that every new NASA administrator should be taken on the Shuttle. Then they would know what it was all about after they had been scared “witless.” In the aftermath of the Challenger disaster there was a hiatus in Shuttle flights for 33 months.
“My God, that’s a lot of damage”
FREQUENT SHUTTLE DAMAGE
STS-26 AND OTHER FLIGHTS
1988 AND BEYOND
After a gap of nearly three years, the Space Shuttle resumed flights in September 1988. Despite the general view that
flights from now on were going to be safer than previously, even return-to-flight mission STS-26 was about to experience the type of life-threatening incident that was the dread of all astronauts.
Commander for the Shuttle’s return to flight in September 1988 was Rick Hauck:
I was absolutely thrilled that I was entrusted with that mission. I think every member of the Astronaut Office, probably without exception, wanted to be on that flight. I did tell my family: “This will be the safest flight ever flown by NASA, STS-26.” What I did not say was: “And that guarantees that I’m coming home,” because, of course, there’s no guarantee. But I was comfortable that, within my view, everything had been done to prepare everything for that flight.
A lot of people, when they hear you flew once before Challenger and twice after, assume you must’ve been scared more after Challenger, and I said no. I was terrified on my first launch, I was terrified on my second, and I was terrified on my third. Challenger did not change the fear factor at all. If anything, it was a very slight sense that it was safer on the post-Challenger missions than it was before because people were more focused. Disasters tend to do that, tend to focus folks. So I had this sense of maybe a little slight less apprehension about my second mission, although in lots of ways I was still terrified. Challenger didn’t change a thing.
Prior to 51L, we had never lost a crew after launch. They lost the Apollo 1 crew and, of course, astronauts had been killed in airplanes and car crashes and so on, but we’d never lost anyone in a spaceflight. So even though on STS-7 and STS-51A I knew this was dangerous, I kind of comforted myself with the thought: “We’ve never lost anyone before, so we’ve got this wired; we know how to do this.” Well, that comfort could no longer be delivered by that thinking after 51L. I was convinced that everything had been done that could be done to prepare the machine and the crew and the software, but I knew that my good friends had died the last time a machine had launched. I do absolutely remember counting down after liftoff to solid rocket motor burnout and two minutes and ten seconds after launch and the solid rockets are gone, and I remember thinking: “Well, glad they’re out of the picture.” I didn’t mention that—I forget. Launch plus about 20 seconds, we did something called an SM alert, SM being a systems maintenance minor alert, but it’s something that was annunciated. It was a minor issue, but it sure got our attention there for a period of time.
STS-26 crew (from left to right): Mike Lounge, Richard Covey, David Hilmers, Rick Hauck and George Nelson.
Heat Tiles Damaged on Launch
Discovery entered orbit safely and released the tracking and data relay satellite, which was its primary mission. Then the crew gave their remembrance of the Challenger crew.
Once in orbit, Mission Control contacted the crew and asked if they had seen anything pass by the window during launch. They confirmed that they had not. However, one of the engineering cameras viewed after the launch appeared to show something breaking off from the tip of the solid booster and flying down. Mission Control was concerned that this object may have struck the Orbiter’s belly, causing damage, and so the crew were instructed to use the robot arm to look under the belly. What they saw shocked them. Something had extensively damaged the heat-resistant tiles that protect the Shuttle during reentry.
Hauck: We were looking at this and saying: “My god, that’s a lot of damage.” And we saw one place looked like a tile was completely missing, but it looked to us like there was a lot of, lot of damage on the belly of this thing. We told Mission Control and they just kind of seemed blasé about it, like they were looking at the video, and they just didn’t have a sense of urgency like I think we did, and expected them to have. It kind of baffled us. We said: “Why are they not more concerned about this?” It was obvious to us there were probably hundreds of tiles that were damaged. And when we came back, it turned out that the video was such a poor quality with the Sun shining on those black tiles, it’s hard to see things, is that they really couldn’t see what we were seeing, and they saw a few scrapes and scratches and stuff and didn’t think it was all that big of a deal, and I think everybody was shocked when the vehicle landed, and I think they ended up changing out like 700 heat tiles or something. It was a lot of heat tiles they had to change out that were damaged on that thing.
Many Successful Satellite Launches and Space Station Missions
The Space Shuttle program was never quite the same after the Challenger accident, even though it achieved a respectable, and safe, flight rate of about seven missions a year throughout the 1990s. Nevertheless, it launched the Magellan probe to Venus, the Galileo probe to Jupiter as well as the Ulysses probe into deep space. It also placed into orbit the great space observatories: the Hubble Space Telescope, the Chandra X-ray Observatory and the Compton Gamma Ray Observatory. It must be noted, however, that these remarkable satellites could have been launched on unmanned rockets—like the Spitzer Infrared Space Observatory was, on a Delta 2 rocket. The Shuttle repaired the Hubble Telescope several times in orbit, greatly extending its life and scientific productivity. It flew nine missions to the Mir space station and many more to its successor, the International Space Station.
In October 1998—35 years after he became the first American to orbit the Earth—John Glenn returned to space on mission STS-95 becoming, at 77, the oldest person in space. This time he added another 134 orbits to his tally, ostensibly studying how an elderly person would adapt to zero gravity, as well as undertaking investigations into the aging process, though it is questionable whether anything scientifically worthwhile was achieved.
The Space Shuttle has performed well, even with the to-be-expected close calls, but it will never be truly “operational.” Using it to get into space involves the liberation of titanic amounts of energy that are too unforgiving of mistakes.
More Lucky Escapes
On the 95th Shuttle flight (and the 26th launch of Columbia), a small pin in the combustion chamber of one of the SSMEs broke loose during the early ascent phase. The pin was put there to “repair” a previous fault. It struck the rocket’s nozzle, puncturing its coolant jacket which was fed with liquid oxygen—the Shuttle’s fuel. Columbia began to leak. It was not the only problem during launch. Five seconds after liftoff a short circuit disabled some of the controllers of two of its SSMEs. Columbia’s computers switched to the reserve controllers of the main engines, but it meant that two of its three rocket engines were one failure away from shutting down. Luckily, nothing else happened and the fuel leak was small. Columbia reached orbit safely, albeit a few miles lower than expected. But, as is so often the case, it could have been much worse.
A much more serious problem occurred during the launch of STS-112—an Atlantis flight to the International Space Station. Only one set of the “hold-down bolts” fired. Detecting the failure, the launch computer fired the backup system to release the bolts. It was vital that the bolts were free when the SRBs fired, otherwise Atlantis would have torn itself to pieces.
TIMELINE
1988 29 September Shuttle STS-26 is launched, marking the first Shuttle flight since the Challenger disaster in January 1986
1989 4 May Shuttle mission STS-30 blasts off, and launches the Venus probe Magellan
18 October Shuttle Atlantis is launched on a mission that includes the deployment of the Jupiter probe Galileo
1990 24 April Shuttle Discovery is launched, carrying the Hubble Space Telescope
6 October Shuttle Discovery is launched, carrying the probe Ulysses
“It’s serious. It’s serious”
FIRE AND COLLISION
THE MIR SPACE STATION
1994–2001
The most difficult and dangerous space missions since the first Moon landings and Shuttle flights were the expeditions aboard the Russian Mir space station. The Shuttle–Mir program was a collaboration between the United States and Russia during which Space Shuttles docked with Mir and US astronauts spent considerable periods on board the space station. During seve
n manned expeditions, Americans spent almost 1000 days in orbit. The collaboration saw the first American astronaut launched aboard a Soyuz and the first Russian cosmonaut flown on a Space Shuttle.
Rendezvous with Mir
The first phase of the collaboration began with the launch of Shuttle STS-60 in February 1994, with cosmonaut Sergei Krikalev on board Discovery. Although the Shuttle did not dock with Mir, there was a video link with the three cosmonauts on board. A year later the first female to command a Shuttle flight, Eileen Collins, flew Discovery alongside Mir. This time Russian cosmonaut Vladimir Titov was on board the Shuttle. A few months later astronaut Norm Thagard took off in a Soyuz capsule with Vladimir Dezhurov and Gennady Strekalov to visit Mir. He remained there for 115 days. They returned in July on Space Shuttle Atlantis, which carried out the first Shuttle–Mir docking after delivering two replacement cosmonauts. In 1995 the Shuttle delivered a new Docking Module and new solar arrays.
The following year the US maintained a significant presence on Mir. Shannon Lucid stayed for six weeks, up to September 1996. John Blaha took her place until the following January. Then Jerry Linengar stayed until May. While on board he faced one of an astronaut’s worst nightmares—a fire in space.
Space Shuttle Atlantis leaving the Mir space station during the 1995 STS-71 mission.
Fire!
There was a crew of six on board Mir at the time, February 1997. Usually they ate in shifts, but since that day was Russian Army Day they took a meal together. After the meal it was cosmonaut Aleksandr Lazutkin’s routine task to reload a so-called oxygen candle in the Kvant Module. The oxygen generator uses three lithium perchlorate candles each day. When heated, they generate extra oxygen. As Lazutkin floated away after performing the task, he heard a hiss and then saw sparks quickly forming a flame. Reinhold Ewald, a European Space Agency (ESA) astronaut, saw it and shouted “Pozhar,” meaning “Fire.” Vasily Tsibilyev echoed his call: “Pozhar. Pozhar.” Commander Korzun arrived with a fire extinguisher and the others grabbed one, too. The fire was growing. Black smoke was beginning to form. Lazutkin tried to switch off the device but there was no response. He threw a wet towel on it but it swiftly burned. Molten metal was dripping from it and the flame was now reaching toward Mir’s hull. If the hull became breached they would die in seconds; they all remembered Soyuz 11. Smoke stung Korzun’s eyes as he flipped the fire extinguisher to “foam” and depressed the button. Nothing happened. He shouted: “Everyone to the oxygen masks, everyone stay in pairs.” He then ordered Lazutkin to prepare the ship—meaning one of the two Soyuz capsules docked at each end of Mir. The second Soyuz could not be reached through the fire. The alarm sounded. The flames were now 0.6 meters (2 ft.) long and growing. Someone shouted: “Where’s Jerry?”