On a mission

Sally Davis is lead flight director for the International Space Station, a job so demanding that no-one ever holds it for more than six months. Christopher Sell reports.

It is now over 30 years since Neil Armstrong took his epoch-making stroll across the lunar landscape, and kindled hopes that mankind was on the verge of a new age of cosmic exploration. Since then the heady ambition of those days has been tempered by a greater understanding of the physiological limitations of the body and the inadequacies of current technology. It was the need to overcome these limitations, and gain a greater understanding of the effect of space over long periods on both the body and materials, that were the driving forces behind the creation of the International Space Station (ISS). Built to maintain long-term human presence in space, and provide a platform for both microgravity experimentation and also ultimately as a first step for far-reaching exploration, the ISS is the result of an international collaboration involving 16 countries. Over four times as large as Russia’s now defunct Mir space station, and expected to be completed by 2010, the ISS is one the largest and most complex international science projects in history and its success is pivotal in the future exploration of space. It’s an understatement to say that managing a project of this scale, and overseeing the disparate range of scientists, researchers and engineers who work on it at any one time, is a pretty demanding job. On the ground, the responsibility all stops with one person: the lead flight director. This position, which changes hands once every six months, is currently occupied by affable Texas Tech University graduate Sally Davis. Davis’s role at the Johnson Space Centre in Houston, Texas, is to lead a team of flight controllers, support personnel and engineering experts, and assume the overall responsibility to manage and carry out Space Shuttle flights and ISS expeditions while orchestrating planning and activities with flight controllers, payload customers and ISS partners. Throughout a long day littered with meetings, the demands placed on Davis are considerable. ‘There is so much to think about and co-ordinate. It’s very high pressure and I’m ready for a break,’ she said, alluding to the fact that her six-month tenure will shortly be over. ‘It’s a pretty constant job, and I don’t think there’s been a moment when I haven’t been thinking about one issue or another.’ Davis’s role is to lend continuity on a day-to-day basis, and ensure that the different elements of the flight team, be they engineers, environmental controllers or increment managers, are working together. The key to this, she said, is the ability to see the bigger picture without ignoring the smaller details. Currently the only person to have undertaken the role twice, Davis is well placed to cope with the pressures of the role. Each mission, or expedition, on the ISS lasts for six months. According to Davis, the key difference between the current expedition (number 12) and the first expedition she worked on (number four) is that first time around ISS was still being assembled. Now those working on the project are primarily concerned with pursuing one of the its main jobs: ensuring a permanent human presence in space. As well as the daily stresses of running ISS, Davis singled out some of the key challenges she has faced over the past few months. These have included overseeing two space walks and moving a Russian Soyuz spacecraft from one docking port to another. The preparation and planning involved in organising a space walk are astonishing. Davis explained that six hours of preparation building up to the event are preceded by two weeks’ work to ensure that the spacesuits are fully functional, a couple of days spent making sure the tools are working, followed by some serious discussion with the astronauts regarding the actual walk. All this planning, which adds up to around six weeks, is essential so that during the event there are almost no unknowns. ‘To be able to complete two space walks, two vehicle moves, all the science involved and getting ready for shuttle missions while making sure it all fits in the time frame may not sound challenging — but it is. It takes a long time for these things to get done,’ said Davis. As if her job were not complicated enough, the Columbia Shuttle disaster has exacerbated the logistical planning inherent in her role. ‘The challenge, anybody will tell you, is that we have limited capability to send things into orbit — we are very reliant on the Russians right now. It’s a matter of managing the resources that are available to us in orbit and ensuring that we are doing the most we can during the time in orbit with what we have,’ she said. She added that, with 16 shuttle flights required to complete the ISS assembly, it’s vital that the space shuttle re-enters service soon. Following the Columbia disaster, there was a profound change in working culture, she said: ‘I was here before Challenger, before Columbia and after Columbia and we are now being a lot more collaborative in the decision-making process. This means there are more opinions to consider, but in the end it has led to more thoughtful and better thought-out plans.’ She added that while NASA’s proposed successor to the shuttle, the crew exploration vehicle (CEV), discussed in this issue’s Feature, will still have a role to play for the ISS, it is likely to be much smaller than its predecessors and won’t be able to carry so much equipment to the orbiting space station. But while one eye is on the logistical demands and the struggle to finish building the space station, the other is focused on the successful projects that the facility is hosting. Recently astronaut Valery Tokarev performed the third session of the ESA/RSA CardioCog experiment, an initiative aimed at gaining a deeper understanding of the effects of microgravity on the human cardiovascular system. In a separate experiment at the end of last year, researchers opened the Polymer Erosion and Contamination Experiment (PEACE). Using a device that has been attached to the outside of the ISS since August 2001, researchers aim to analyse the behaviour of a number of polymers in the harsh environment of space. It is hoped that those that perform best could be used in the future to build satellites and space stations. The group is also studying advanced solar cells on the station to monitor how they perform and endure in space. Researchers from the NASA Glenn Research Centre have been looking into the effects of space on a hybrid solar cell which combines the best properties of silicon and gallium arsenide solar cells, and could in future produce more efficient solar cells that are far cheaper and twice as light. They are monitoring how the hybrid material copes on the outside of the ISS with radiation and extreme temperatures. Though she has a tough assignment, Davis is clearly addicted to the environment — she says she is ready for time off, but she is certainly not relishing the thought of surrendering the huge responsibility of this job. Following a well-deserved break she’s looking forward to taking up her former position as one of a number of flight directors who help keep things running smoothly. ‘It takes a lot of people and energy to keep things running smoothly in a 24/7 environment,’ she said.