Returning to Flight, Continuing to What?
Kennedy Space Center is a rambling complex of buildings old and new that, except for the gaunt launch towers and massive Vehicle Assembly Building, seems barely to rise above the surrounding scrubland. Vegetation growing in the sandy soil of coastal Florida can be reminiscent of a far drier climate because rainwater drains so rapidly; however, a change in elevation of only a few feet can put you in a swamp. The land and water teem with wildlife herons, egrets, alligators, manatees and pelicans are all common sights. To the south of KSC, towns form a linear sprawl along the ocean.
I am spending the summer here as an intern, working on advanced life support. Messing around with fungi and bacteria is not many people's idea of working in the space program, but this research is necessary if long-term human space exploration is to become a reality. As a result, I will get to see the space shuttle launch and discuss the Return to Flight mission with knowledgeable people who have devoted their careers to furthering humankind's presence in space. Here, I will follow Discovery's mission from beginning to end.
Witnessing the Launch
"Godspeed, Discovery!" The signs have sprung up over the past few days, among others offering plumbing repair, Sunday pizza specials, and help against chinch bugs. In spite of it being the middle of the week and a previous launch having been cancelled, tourists have again flooded Cape Canaveral, Cocoa Beach and other towns in what Floridians call the Space Coast. However, there are fewer of them than there were the first time, and the general mood is more subdued.
At Kennedy Space Center, the mixture of excitement and apprehension is even more potent. Even people whose jobs are not directly affected by this mission feel in the air a tension, ill-masked by the work of an ordinary morning.
Twenty or so people gather on the third floor of KSC's Space Life Sciences Lab, a modern building about five miles away from launch pad 39-B. Some watch the launch countdown on the local news; others crowd around the plate glass window. Most have witnessed launches in the past, when they might have been more concerned about traffic from tourists than about seeing the space shuttle take off. But not today. Not two and a half years after Columbia burned up in the atmosphere; not two weeks after a problem with a low-hydrogen sensor in the fuel tank prevented the planned July 13 launch.
The countdown reaches zero and a column of flame grows, framed by two scruffy trees. The fuel burns furiously, but from five miles away, the glowing pillar has a fiery grace. When it dies away, clouds of steam take its place. The steam forms a column that, were it not for its sheer verticality, would blend in perfectly with the cumulus clouds sharing the neighborhood.
As it rises, Discovery seems to fall away towards orbit. Although we cannot see this, it performs a roll to put it in a more stable flying position and allow an easier abort should one become necessary. It jettisons the solid rocket boosters in a puff of steam and continues to rise as it fades from view. Finally, we turn to the television and see, from a camera on board the shuttle, the blue curve of the Earth.
Launch Side Effects
The launching shuttle has two fuel sources. The orange, rocket-like external fuel tank contains liquid hydrogen and oxygen that combine in the shuttle's own engines to produce steam and tremendous quantities of energy. Still, it is not enough. Therefore, two white solid rocket boosters that use powdered aluminum as fuel are attached on either side of the external fuel tank. These separate once they're used up, fall into the Atlantic Ocean and are retrieved by a ship.
The rocket boosters have some unexpected environmental side effects. Burning the aluminum powder deposits thousands of pounds of the metal on the ground. Intense acid rain covers an area on the north of the launch pad, killing vegetation on land and fish in nearby lagoons.
"Normally there's a pH of about 10 [in the lagoons], but after a launch it'll go down to 1 or 2 or lower," says Tom Dreschel, a KSC biologist who studied the issue in the early 1990s. Fortunately, Florida's limestone rapidly neutralizes the acid. Still, contends Dreschel, "I think we need to take the environment into consideration in everything we do." He believes future rockets will be more like the shuttle's main engines, which produce only steam. Unfortunately, acid rain may be the smallest problem shuttle launches face.
The Second Day Flying Foam
"We are in the business of flying in space. It's a very difficult business," said Wayne Hale, manager of the shuttle program, to a gaggle of reporters gathered at a NASA press conference. To everyone's disappointment, several pieces of insulating foam broke off the shuttle's external fuel tank during launch. A painstaking inspection by the shuttle and space station crews revealed no damage to the orbiter, but this is a major setback after Columbia. NASA has improved shuttle safety, but apparently not by enough.
Still, one question hangs in the air, unasked. Complete safety is impossible in driving a car, much less flying a spacecraft. How safe is safe enough?
"There are criteria that we use. They're pretty well defined," said Woodrow Whitlow, Jr., KSC Deputy Director, in response to this question. However, neither he nor anybody else I interviewed could give a numeric cutoff for overall acceptable risk. If one exists, it does not appear to be widely known. This may be reasonable it might make more sense to evaluate systems one at a time. Yet, I wonder, is the public prepared for the risks that must accompany serious human exploration?
Servicing the Space Station
The major purpose of STS-114, the official moniker of Discovery's Return to Flight mission, is to continue building the International Space Station. The station, being constructed in orbit by the United States, Canada, Brazil, Japan and eleven European countries, has been stagnating since the Columbia disaster. The shuttle is the only vehicle capable of delivering new parts to the station and without it, assembly has stalled.
This mission, however, is not for major construction. Instead, astronaut Soichi Noguchi replaces a broken gyroscope and restores power to another one. Also, Discovery brings much-needed supplies. Since Columbia, the ISS had to be resupplied by unmanned vehicles and could only support two astronauts not enough to do much in the way of science. A third may be added when the next shuttle takes off in 2006.
ISS depends completely on resupply from Earth, making it vulnerable to breaks in the supply pipeline. Some recycling does take place. Water vapor remains within the station and is condensed and filtered. Also, a machine in the Russian module Zarya splits water into hydrogen and oxygen, supplying some of the astronauts' oxygen needs. However, everything else must be shipped up and trash must be taken away. This STS-114 does, even leaving extra supplies when astronauts learn the next flight will be delayed.
NASA engineers and administrators take the better part of a week to clear Discovery for landing. People are nervous about thermal protection and, after Columbia, who can blame them?
The shuttle's primary landing site is Kennedy Space Center, where it launches into orbit. The other alternatives are Edwards Air Force Base in the high desert northeast of Los Angeles and White Sands Air Force Base in New Mexico. Discovery was supposed to land at KSC, but cloudy and rainy weather, hardly uncommon in summertime Florida, forced a change to Edwards. There, the shuttle landed as it always does, gliding without power.
The change in location seems to have dimmed no one's enthusiasm on the self-styled Space Coast. In true Cape Canaveral style, a sign at Dunkin Donuts welcomes the astronauts home.
The shuttle will not launch again until March 2006 at the earliest. Current plans call for phasing it out in favor of an as-yet-undesigned Crew Exploration Vehicle. After that, the Vision for Space Exploration announced by President Bush calls for returning to the moon and, eventually, sending humans to Mars. However, some big questions remain.
The first of these is why we should send humans into space at all. It's risky and expensive, critics say. When human exploration becomes a top priority, some purely scientific programs get cut. An editorial in the July 2005 Scientific American says that NASA's "renewed commitment to human exploration is now impinging on its program of unmanned missions". The agency is cutting Earth and Solar System research, such as the solar observatories TRACE and Ulysses. (Ironically, the bioregenerative life support work necessary for long-term human exploration is also taking a hit because of NASA's focus on the CEV.) Robotic missions like the Mars rovers have delivered excellent science at a fraction of the cost of human ones.
However, there are good scientific reasons for human exploration. Robots do not make very good geologists. A human could do in a few minutes what Spirit and Opportunity take weeks to accomplish. Furthermore, there is the matter of human perception and intuition. A scientist in the field can glimpse something from the corner of her eye and quickly decide to investigate. Physically being in a place is different from looking at pictures and may foster a different kind of thinking.
Even granted this, is human exploration worth it? The answer to that question requires that another, perhaps more fundamental one, be addressed. Is there more to exploration than science?
Mike O'Neal has spent almost three decades working at NASA as an engineer and manager. However, he has recently switched gears and is doing a master's degree, looking at ways that people far from civilization have traditionally received spiritual support. He has also thought quite a bit about the reasons for spaceflight.
"From an exploration standpoint. exploring things that are new and sending humans [to Mars], that in and of itself is a spiritual thing to humankind," says O'Neal. "Technology is kind of a byproduct." He believes space travel will provide new perspectives for the humanities and social sciences. "I think it would be very interesting to have a writer or a poet go to Mars and bring back their product. It would be so unique."
As O'Neal talks about human experience in space, his eyes light up. "When you had a human, for the first time, leave Earth and go to the Moon and they start orbiting the Moon. They come around the back side of the Moon, and, for the first time ever, you had human beings witnessing an Earthrise. And that has affected humanity [and] how we view our Earth. That's the kind of thing you may get from sending humans to Mars."
Many have said that the urge to explore is intrinsic to humanity, that it is part of who we are. Science is one kind of exploration, largely mental. But we are physical beings and to physically step into a new place carries an emotional significance that transcends pure knowledge. Paradoxically, this is where some of our most profound insights come from, driving both science and culture. From robotic exploration, we gain knowledge, but from human exploration, we gain wisdom.