It is the depths of night over Europe in February 1992. The darkness across the continent is deepened by a thick, seemingly impenetrable layer of cloud. Suddenly, a shaft of light cuts through the gloom, illuminating a circular area five kilometres in diameter in Southern France. The beam moves eastward at 8 km/hr, sweeping across Switzerland, Germany and Czechoslovakia, before disappearing over Belarus with the coming dawn. What could have caused such a mysterious event? Was it a sign of an impending astronomical disaster, or even a sign of alien contact? Thankfully any sleepless people who witnessed the confounding phenomenon could rest assured: what they had experienced was terrestrial in origin and was in fact a hugely ambitious space project over 70 years in the making.
A Crop Conundrum
Following the breakup of the Soviet Union, the newly formed Russian Federation took its place as the largest country on Earth. However, in addition to the myriad economic concerns blighting the inaugural Russian government, it also faced an agricultural one: a mere 7.3% of its land was categorised as arable – land capable of being ploughed and able to sustain crop growth. This paled in comparison to their cold war adversary the United States, which benefitted from 16.8% arable land, and neighbouring ex-Soviet block countries such as Ukraine, Romania and Belarus, at 57.6%, 39.1% and 27.8% respectively1.
Image from Erokhin, V., Gao, T., & Ivolga, A. (2020). Structural Variations in the Composition of Land Funds at Regional Scales across Russia. Land, 9(6), 201. https://doi.org/10.3390/land9060201
The newly independent constituents of the Soviet Union had long fed the masses across the nation, making up for the crop-growing deficiencies of the Russian state. Moving forward, If the newly formed Russian nation was going to emerge as a leading superpower, it needed to find a way to feed its own people.
Russia was not afraid of ambitious projects to solve this potentially existential problem and, as it had done so often in preceding decades, turned its gaze towards the stars. As some Russian scientists saw it, there was little that could be done about how little of their vast nation’s land was unsuitable for farming – indeed, almost 65% of Russia is covered in permafrost2. Instead, Russian farmers would have to find a way to turbocharge crop production in the slivers of arable land that did exist.
A Solar Sail Solution
Crop growth is driven by a range of fundamental limiting factors: crops need access to water, nutrients and, crucially, sunlight. Without the ultraviolet radiation derived from our Sun, plants are unable to photosynthesise and convert light energy into chemical energy, driving their metabolism and growth. It goes without saying that plants are therefore unable to maintain constant photosynthesis levels at all points of the day. Though light energy can be stored and hence some photosynthesis can continue during the night, the sun dipping below the horizon as the Earth completes its rotation puts the brakes on photosynthesis until the following morning. It is this fundamental notion that Russian scientists aimed to challenge as the 20th century came to a close. Their proposal was radical – to harness the power of the Sun no matter the time of day, to bathe fields veiled in the darkness of night with nurturing sunlight. Led by Vladimir Syromatnikov, who had previously worked on the Bostok spacecraft on which Yuri Gagarin became the first human in space in 1961, the Russians commissioned the Znamya project in the early 1990s.
Russian for ‘banner’, Syromatnikov originally devised the Znamya project as a massive solar sail, which would harness powerful solar winds – streams of radiation produced by the Sun – and propel spacecraft across the solar system and beyond.
By this stage in post-Soviet Russia, though, the country’s leadership had emphasised maximising productivity above all else. It also simply could not afford such novel and ambitious projects. Encouraged to keep his aspirations more terrestrial in nature, Syromatnikov took inspiration from the work of pioneering Romanian rocket scientist Hermann Oberth. In his 1929 book ‘Die Rakete zu den Planetenraumen’ (The Rocket to Interplanetary Space), Oberth had outlined the concept of a solar mirror – a giant object placed in orbit above Earth which, when properly orientated, would reflect a vast beam of sunlight down onto the planet’s surface3. Oberth envisioned a field of enormous 300 km diameter mirrors illuminating the darkened surfaces of Earth with a view to not only increasing crop yields, but also lighting cities, safeguarding against natural disasters and even manipulating the climate. Clearly, some aspects of Oberth’s vision were ahead of their time, though others, such as the hardy space engineers clad in diving suits, reveal the limits of technology and imagination at the time.
Inspired by Oberth’s work, Syromatnikov reformulated his Znamya project to become a solar mirror, designed to meet all the potential benefits suggested by Oberth, whilst also ticking off additional utilisations such as massively increased electricity production via solar panels.
The Russians launched their first large scale proof of concept, named Znamya 2, in February 1992. The satellite consisted of a thin and delicate 20 m (66 ft) reflective film deployed from the Progress M-15 spacecraft:
A scaled-up Znamya 2.5 test was swiftly commissioned, with the aim of growing the diameter of the reflected sun beam but up to 50% and reaching a brightness of 10 full moons, known as lunettes. By this stage in the project’s development, Russian scientists believed that the best use of the technology would be to develop a satellite that could focus a beam of light on a single target on the Earth’s surface, such as in areas near the poles that experience prolonged periods of darkness, or be deployed in specific circumstances, such as providing emergency lighting during large scale disasters. Unfortunately, Znamya 2.5 was not as successful as its predecessor. Following its launch in February 1999, exactly seven years after Znamya 2, the fragility of the reflector sheet led to a catastrophic failure: it got caught on one of its host spacecraft’s antennae, failing to open and ripping. Though two further launches were planned, the failure of Znamya 2.5 ultimately saw the end of the mission. Costs had spiralled to untenable levels and a newly established Vladimir Putin had begun shifting the priorities of the nation he now led. Syromatnikov had dedicated well over 10 years of his life to the project he so firmly believed would revolutionise the Russian economy. Though his legacy would live on in the docking mechanisms that still form a core part of the International Space Station, it would appear that he would unfortunately never come to be known as the man who harnessed the Sun.
Znamya Reborn?
Now, though, more than 20 years after the end of the Znamya programme, interest in solar mirrors is beginning to grow again. As we look to dramatically reduce our reliance on fossil fuels and continue to meet growing energy demands, solar mirrors are once again being mooted as a method of optimising the production of electricity from renewable sources. A research team at the University of Glasgow is championing a series of reflective discs in orbit around Earth, taking direct inspiration from the proposals of Oberth and Syromatnikov throughout the previous century. The latest iteration would involve several hexagonal reflectors, with each side measuring 250 m, positioned 900 km above the Earth. The reflectors would be placed in orbit in a specific location and orientation to target identified solar farms. The research team estimates that such an arrangement would enhance operation by 30 minutes at the tail end of each day, when demand for energy is often highest4.
Scientists have toyed with the concept of space mirrors for over 100 years. The proposed functionality of the technology has barely changed in that time, but how scientists envisage their use has shifted with the evolving priorities of our society. From Hermann Oberth’s aim of lighting cities in times of crisis, to Syromatnikov’s solution to a Russian crop crisis and now suggestions of enhancing renewable energy production, solar mirrors continue to fascinate us.
With an urgent need to squeeze every bit of efficiency out of our solar farms, perhaps we will now finally see solar mirrors installed in our skies.
