Opinion It’s time to celebrate Sunita Williams and Barry Wilmore’s safe return. Scientists must now use their experience for future space expeditions

Not that this is the longest time an astronaut has ever spent in space. That record has been held for a long time by the Russian cosmonaut, Valeri Polyakov, who stayed for almost a year and a quarter in the Mir space station back in 1994. But that was a planned mission. Most space missions do not last that long, and the question mark hanging over the return of Sunita Williams and Barry Wilmore has been darker than how space itself looks like from the space station window. Their travails, brought alive to earthlings through pictures and video clips, has had almost everyone’s eyes glued to the orbiting space station.

What travails, one might ask. Before you start thinking of life inside a space station as a vacation in an isolated retreat, lounging in rooms with a spectacular view to boot, consider the plights of spending months in a space station, with thoughts of being rescued gnawing at your brain all the time. One wonders if the sight of the home planet, constantly acting as a reminder of the distressing predicament, is helpful at all.

As the recent Booker prize winner Samantha Harvey has described in her novel Orbital, astronauts probably often take a second look at the blue planet “to check that the earth and its seas are not just dreams or mirages”. Some have described this “overview effect” as an inspiring sight that strengthens the bond between astronauts and fragile humanity; others have murmured their dissent.

Even if one ignores the deep psychological effect of being stranded, the effect of zero gravity on the body is unmistakable. While astronauts are trained to operate under zero gravity conditions, the human body is not designed to do so for a significantly long time. We don’t realise this in our daily lives, but the pull of gravity is crucial for our bone maintenance. In contrast, bones need not be strong enough to support the body in space, and so new bone cells are not produced at the usual rate. This leads to a loss of bone density, which would be devastating for astronauts after returning, because the damage is irreparable. Muscles everywhere in the body, including the heart, also suffer atrophy.

The way our blood circulates changes in the absence of gravity, too, with the head getting more than its share. This reduces blood volume and increases the chance of clots. Not only blood, but other fluids build up in the head — astronauts could experience what feels like a constant cold. The accumulation of fluid also distorts the shape of astronauts’ eyeballs, weakening their vision. The upshot is that upon their return, they will have difficulty in walking, problems with their eyesight, and would often feel dizzy.

One might say that the feeling of having a constant cold is a good thing in the space station, though. This is because the smell up there is nothing to write home about. Imagine a room that has not been opened, and where astronauts have been regularly visiting for two decades! One must be thankful for small mercies after all.

Then there is the danger of being exposed to high energy particles in space. On Earth, we are protected by a sheath of magnetosphere, and the harmful effects of these particles — coming from the Sun and deep space — are minimised for our benefit. There are also particles trapped in the geomagnetic field. While the bombardment of such particles on the body certainly increases the chance of cancer, especially during space walks, the extent of this effect has not yet been quantified. This is a major concern for the present mission, particularly because Sunita Williams has clocked more space walk hours than any other woman in history.

Scientists have been worrying about the problem of radiation exposure in space for a while, but there are no “case studies” yet. One has to solve this radiation exposure problem to some degree of satisfaction before planning to send astronauts to Mars or the Moon for longer durations. Williams and Wilmore may play an important role in future studies in this regard.

While scientists can plan all these studies in the future, it is now time to celebrate the safe return of the pair. The resilience and reserve of patience of not only the astronauts, but also everyone involved in the rescue mission, have ensured that the story has a happy ending.

The writer is an astronomer, science writer and novelist