by Roger Wiens
The tracking camera followed the Genesis capsule as it continued plowing into the Earth’s atmosphere. As it got nearer, a tumbling action could be seen. After this continued for over a minute, the voice on the audio eventually remarked dryly, “Negative drogue, negative chute.” The audience began to whisper. The picture of the tumbling capsule became increasingly clear so that features could be easily distinguished. Four and a half minutes had gone by since we first saw the capsule. No one was cheering now. A voice announced, “Expect an impact,” and immediately the horizon appeared in the background. Then the picture went blank.
A sickening gasp went up from the crowd. “We have impact,” came the voice over the audio. One of the helicopter pilots didn’t fully understand the situation and radioed for an altitude. The reply came back that the capsule had impacted at ground level. A few seconds later, the picture showed a broken capsule lying on its side on the desert floor.
In the hangar, confusion reigned for a short time. Roger Snodgrass, a local reporter from Los Alamos, sprinted up to the front to get my first impressions. Following his lead, the other reporters decided I was the authority of the moment, and within seconds I was surrounded by at least twenty microphones and cameras.
It was probably the best-staged disaster since Evil Knievel had tried to jump a rocket-powered motorcycle over the Snake River Gorge. The fact that this capsule was my baby—I had worked fourteen years for this day—made me the perfect media target. The reporters wanted to know what I thought of the disaster, my own response to the tragic loss, and how I was going to cope with it. My first reactions, however, were to recall how we had planned for this possibility starting ten years earlier, and how our plans would now pay off. We had considered other possibilities—that the spacecraft would be lost in space, or that the capsule might fail during reentry, spreading debris over hundreds of square miles, as the Columbia space shuttle had done just a year earlier. Or it could have smashed on a mountain peak near the range, breaking into a million useless pieces. In the collection of disasters we had talked and planned our way through, this one was of moderate consequence: we had our samples on the ground, but they were broken and dirty. We would deal with it.
The press, however, was not interested in my reassurances. They had seen a terrible crash and they wanted to paint the disaster in the worst possible light: “This wasn’t supposed to happen, was it?” “What did you feel like when you saw the capsule hit the ground?” “Is NASA going to get anything out of this wreck?” “Isn’t this another terrible disaster for NASA?” I assured everyone that this was different from a Mars crash. The samples would be recovered and analyzed; we had planned for this possibility. But the questions just kept getting worse and worse. It was clear that the news media wanted to portray the crash as a dire failure, but I was determined not to give them that opportunity. The polite stand-off went on for about ten minutes, at which point I was rescued by the JPL media relations person, who physically pulled me out of the crowd. The rest of the interviews would have to wait until after the official press conference.
Meanwhile, I tried to find out what was happening with the recovery crew. The VIP hangar was on one side of the desert runway, while the control center and the capsule’s destination were on the other side. I ran to my car. The security guards, who surrounded every building in the area, were looking dejected.
Once in my car, my eyes flooded in a brief downpour. My thoughts raced through the comments and questions by the reporters. Yes, this was a disaster. Something terrible had happened. This was not at all the way it should have gone. I was torn. I knew we should still get results out of Genesis, and yet, with everyone saying it was a disaster, I was slowly beginning to think they were right.
At the control center I braked the car to a fast stop and ran inside, where I caught up with the recovery crew. People were grabbing shovels, tarps, cameras, and gloves from an emergency kit. The recovery crew started to head out to the site only to be called back for a planning meeting. The military escort helicopter landed at the site and a few people began inspecting the capsule from a short distance, still wary of the unfired pyro devices that should have deployed the parachute.
Back at the hangar, a hasty news conference was called. As the cameras were ready to roll, the leader of the mission was nowhere to be found. Feeling responsible for pushing the temperature limits of the parachute battery, Don was in no mood to appear in public. He was afraid that he was to blame for this failure and couldn’t bear the thought of appearing reassuring in public when deep down he thought it was his fault.
The spacecraft team had in fact planned for the event of a crash. One of the most important contingency measures was to use a unique thickness for each sample collection wafer. In the event of broken wafers, the pieces could be identified by their characteristic thickness. This was an important detail, since an impact of this magnitude left almost no wafers in their places. As the press conference began, the crew made their way out to the crash site.
The recovery team began the ponderous job of picking up the pieces. The first action was to disarm the explosive devices that should have deployed the parachute. The parachute deck had broken open, so clipping the leads could be done without too much prodding. Once this was completed, the crew took a careful look at the capsule to see how best to remove it.
The capsule had hit completely on edge and had nearly split into several pieces. Most of the heat shield, which had protected the capsule during the hottest part of the reentry, was separated from the rest. Likewise, the parachute deck on the top had nearly broken apart. In the middle, the canister had cracked open, spilling some of the broken solar samples onto the ground.
The crew removed the capsule one section at a time, taking care to protect the samples as much as possible. The parachute deck was extricated first, followed by the heat shield. The pieces were loaded onto a “mud puppy,” a funny-looking cross between a tank and a truck, which was used to move heavy equipment in and around the muddy salt flats. The removal of these first sections allowed the crew to view the full extent of the damage to the sample canister.
After removing various outer parts of the capsule, the crew carefully laid a tarp next to the exposed sample canister and began lifting it onto the tarp. It weighed about as much as a human body and required several people to lift. The crew placed one more tarp under the whole thing, and holding the edges, they carried the gurney to a waiting helicopter. Several crew members stayed until dark sifting through the small hole left by the impact to pick up any remaining sample-collector shards or debris from the stricken vessel.
The recovery crew had reported that they could not locate the concentrator target, one of the most important collectors. I was unsure if the crew simply did not know where to look or if it was really missing. I stayed around the control center until the tarp-covered canister was retrieved, but drove back to Salt Lake City without getting to see the stricken unit uncovered. The whereabouts of our precious target haunted my dreams that night.
The next morning I was assigned to locate the concentrator target, wherever it might be. When I went to see the canister, the technicians who had worked with it at the crash site warned me, “You’re not going to feel good about what you see.” The feeling I had throughout the disassembly operation was like working on a wrecked car that I had driven for many years. It wasn’t quite alive, but it was definitely a familial object.
The canister was lying upside down, still on tarps, with a gap of several inches between the bottom and top halves of the clamshell. I could look in and see our gold-coated concentrator among the debris. It had retained its shape, but the interior structure was mangled. Normally the target was positioned at the center of the instrument, facing back toward the mirror. But the interior structure had all been shoved to one side by the impact. All we could do was look in through the gap with a flashlight and mirror. After a number of attempts, a colleague was able to position the mirror in a way that the target samples were
visible. To our huge relief, almost the whole assembly was still there, unbroken! It was a miracle. We went on to identify several other unbroken sample collectors—a large gold foil to be used for one of the top science priorities, and several brittle collectors that were still on the arrays they had been mounted to.
Meanwhile, another press conference was called to let the media know that we had found samples in good condition. Having caught the public’s attention with the terrible disaster, the reporters were happy to follow this big story up with more news from the crash site. In their desire for extreme stories, the media was willing to paint a new picture of great success. The full story, of course, would not be told for several years, when the samples were actually analyzed and the scientific results—the real goals of the mission—were determined. The success or failure to obtain the desired results would be the ultimate judge of the mission.
The recovery crew had spent several weeks before the landing setting up a cleanroom in a large building near the airstrip. It had been built to prepare the sample canister for shipping to Houston, where the samples would eventually reside in a secure facility next to the Moon rocks. But the cleanroom had also been built as a contingency in case further operations were necessary in Utah. We were now thankful to have the facility.
After removing the last bit of debris from the crash site, and assessing the exterior damage to the canister, the recovery team settled down to the task of opening up the sample canister and removing the samples. Before cutting into the canister, the crew first took a trip to an industrial hardware supply store to buy an assortment of bolt cutters, pliers, light power tools, and crowbars. Many of these tools were foreign to our team of engineers and technicians. One additional person was sent out from JPL to coach the team on “disassembly.” Eventually the group settled into a routine of first removing any accessible samples, then identifying the next piece or layer of debris to be removed, finding the weakest place at which to cut it away, and with a few snips or drill holes, pulling it free. Then the process began again. As the samples were retrieved, another group cataloged them and sealed them into containers for shipping to Houston.
We put the cause of the crash out of our minds as we focused on the immediate task of recovering what we could.
Just three days after the event, one of the leaders of the spacecraft team approached me with a more somber look than usual under the circumstances. He took me aside and revealed that his engineers had discovered the reason for the crash. The first words out of his mouth were that it was not the parachute battery. Don Burnett and the science team were exonerated—we had not brought the disaster on ourselves by pushing too hard to get in all of our collection time. I felt a huge sense of relief. Then he proceeded to tell me the cause: a mistake in the avionics unit. The parachute was to be deployed by accelerometers that sensed the deceleration of the capsule during reentry. These units were to start a timer that would deploy the chutes after the proper delay. However, the accelerometers had been installed upside down—both of them! The design drawings were wrong, and all of the tests and reviews—even the extra reviews following the two Mars mission failures in 1998—had failed to catch the problem.
There was another capsule built by the same company that was due to reenter with comet samples in two years. Fortunately, even though the avionics unit on the Stardust capsule was nearly identical to Genesis, its accelerometers were installed correctly. There would be no repeat of the Genesis crash.
chapter
seven
VINDICATION
OUR MORALE REACHED A LOW POINT FOLLOWING THE retrieval of the sample canister after the crash. Yet as more samples were found and retrieved, our spirits steadily rose. It was almost like having a sandbox full of buried treasures at a kids’ party. As each treasure was found, team members outside of the cleanroom would gather at the windows and cheer. The commanding officer of the base even came over when word reached him that a particularly important piece was about to be removed. It was clear that Genesis had survived the crash and that the mission could still be scientifically valuable.
There were consequences, of course, of the crash. It took much longer to analyze the samples than had been planned. There were complications, not only from the small size of the sample fragments and the contamination from the crash site, but also from in-flight contamination. Engineers had built safeguards against such contamination when constructing the spacecraft, but many materials emit vapors in the vacuum of space, and these can end up condensing on the clean surfaces. Despite these challenges, after enough cleaning the samples were finally ready for measurement and examination.
The main goal of the Genesis mission was to determine the ratio of oxygen isotopes contained in the Sun.* Back in the 1970s, scientists had started measuring isotope ratios in meteorites and in the newly obtained Moon rocks. The isotopes of most elements were found to be invariant among different planetary materials. However, the isotopes of oxygen showed remarkable variability between meteorites—rocks that originated on different asteroids. What could this be telling us about the solar system? For more than thirty years the cause of the oxygen isotope differences remained a mystery, and cosmochemists joked that the answer was the Holy Grail of the solar system.
Scientists posited several theories to explain the oxygen variations. One theory suggested that the solar system was formed from material consisting of dust and gas, with the dust having one oxygen isotopic composition and the gas another. Mixing of the two was incomplete, so different solar system bodies ended up with different oxygen compositions. A second theory suggested that a chemical reaction had occurred early in the formation of the solar system that caused some of the meteorites to have oxygen isotope compositions that differed from that of the Earth and Sun. These two theories both predicted that the Sun’s isotope composition would be quite like the Earth’s.
A third, little-known theory was revived while Genesis was in flight. It suggested that ultraviolet rays from the early Sun had caused the chemical reaction of the rare isotopes, oxygen-17 and oxygen-18, to predominate in the planet-forming regions. This same reaction would have taken place for the more common oxygen-16, but there was so much oxygen-16 near the Sun that the ultraviolet rays affecting this isotope were absorbed, much in the way the ozone in our atmosphere shields us from rapid sunburn near sea level. This theory uniquely predicted that the planets contained much more of the rare isotopes than the Sun did.
The Genesis team expected the measurement of solar-wind oxygen to be difficult, as this element pervades every material on Earth. The solar-wind concentrator was specifically designed and flown to improve our chances of getting enough oxygen to beat the background signal. In addition, a special laboratory instrument was built under the direction of Kevin McKeegan at UCLA to analyze our samples. The amalgamation of two normal analytical instruments, this machine was particularly big and impressive: it pulled out ions from the sample collectors, separated them with magnets, accelerated them to 16,000 volts, sent them through a super-thin foil, and then finally analyzed the isotope ratio. The machine weighed several tons and occupied a large room, with the ion flight path running around its perimeter.
Because of the importance of this measurement, the UCLA team took numerous precautions to make sure the new instrument was completely ready to go before risking the precious Genesis samples in it. They went through several preparation runs with practice samples before they felt comfortable enough for the real thing.
March 9, 2008. Houston, Texas, three and a half years after the crash: I awoke before the alarm went off. It was the first day of daylight savings time and the dawn was just beginning to illuminate the sky and brighten my hotel-room window. I had been dreaming about the Sun. For a couple of months I had heard that my friends at UCLA were making progress in measuring the Sun’s oxygen isotopes. Just two days prior they had e-mailed me. The result was clear: The Sun’s oxygen was completely different from Earth’s. The measurement showed strong depletio
ns in the rare isotopes, just like the ultraviolet shielding theory had predicted. Kevin McKeegan was going to report it to the Genesis meeting this morning in Houston and to the science community the next day. This was exciting news. Taking into account that the Sun is thousands of times bigger than the Earth, we Earthlings are the ones whose composition is anomalous.
The new results would give theorists a lot to chew on. In trying to understand something as complex as the genesis of our solar system, scientists need to clarify many individual details before they can see the larger picture. Science makes progress by jumps and starts; theories get hung up for lack of more evidence, sometimes for years, and then, all of a sudden, as some new data comes in, a lot of progress is made in a little time. The results from Genesis constituted one of those jumps.
The important thing for me was that Genesis had accomplished its mission after all. I was right when I told the reporters at the crash that we would still make our measurements. It was a good feeling.
After a short breakfast I went outside to my car. The dew was heavy on the grass and on the car windows. It was quiet this early on a Sunday morning; the city looked almost deserted. I made the short drive from my hotel to the University of Houston in Clear Lake, where our meeting was to be held. The parking lot was empty; the sound of birds from nearby trees filled the air.
The Sun was just rising, orange through the mist over the nearby bayou. I stopped to watch it clear the trees. Once it was fully visible I took a long and knowing look at it. In my mind it seemed much more familiar. For the first time ever, we knew its secrets—we knew.
The Genesis mission went on to reveal more secrets about the Sun and the solar system. A couple of years after the oxygen measurements, scientists at UCLA and in France used the concentrator targets to determine the isotopic composition of solar nitrogen. To their surprise, they found that the Sun and Earth differ even more dramatically in their ratio of nitrogen-15 to nitrogen-14. Like its oxygen, the Earth’s nitrogen is enriched in its rare isotope relative to that in the Sun.