We are approaching summer, and for the residents of the northern hemisphere like us, the night sky sets the stage for the greatest glide-past of human ingenuity. Just that this glide-past happens at a speed of 28,000 kmph. That is the speed at which the International Space Station, or ISS, orbits the Earth at an altitude of 370-480 km. At that pace and height, the space station zips around the Earth every 90 minutes, crossing the sky as we see it in under six minutes.
The ISS is the Earth’s biggest satellite, and technically, the third brightest object in the sky – after the Sun and the Moon. But what makes this ‘satellite’ different is that it’s a large science laboratory, manned by a crew of over six specialists, who stay there for up to six months on specific missions, while some astronauts have remained on board for up to 340 days.
ISS, and other space stations, are among the great achievements of human space research and engineering, and depict our desire to truly go deeper into the cosmos. Recently, Prime Minister Narendra Modi set an ambitious goal of India having its own space station in orbit by 2035, for which ISRO has already started the groundwork. The space station, called the Bharatiya Antariksha Station, is slated to be placed in low-earth orbit, and could house 2-4 astronauts. This feat, while not only boosting ISRO’s already legendary prowess, will also heighten India’s space prestige, putting it in a select club of space-faring nations, including the US, Russia and China. With this, India would become the fourth country to have an independent space station in orbit.
A satellite with people
From Star Trek to Star Wars, humankind has always been charmed by the prospect of sailing into the cosmic abyss on a spaceship. Space stations almost reflect that reality, highlighting the science in what is otherwise science-fiction.
Technically, space stations are large artificial constructions (satellites with people on board) in orbit that possess a pressurised enclosure, power, supplies, and environmental systems necessary to support human habitation for extended periods of time. A small space station can be launched fully-assembled, but larger stations are sent up in modules from Earth on specialised spacecraft and assembled in orbit.
To ensure efficiency of carrier vehicle capacity, a space station is always launched vacant, with crew and additional equipment following in separate craft. When the Soviets launched the Mir Space Station in 1986, cosmonauts Leonid Kizim and Vladymir Solovyov shuttled between the retiring Salyut 7 and Mir.
A space station’s operation calls for a transportation/docking system to ferry crew and hardware and to replenish the propellant, oxygen, water, food, and other essentials, as are consumed during routine operations on board. In terms of electrical power for everyday use for crew and equipment and for orbiting, space stations use large panels of solar cells and storage battery banks, while also relying on geostationary relay satellites for communication with ground mission control and satellite-based positioning systems for navigation.
These stations have docking ports to allow other spacecraft (such as shuttles) to dock to transfer crew and supplies. The purpose of maintaining an orbital outpost varies depending on the programme, including scientific (study of celestial bodies, Earth’s resources, climate, healthcare, and environment), military (reconnaissance), industrial, and even tourism. American engineer Dennis Tito became the first space tourist, when he funded his own trip of eight days on board the ISS EP-1, a visiting mission to the ISS, in 2001.
Journey to the ISS and beyond
The first station was launched by the erstwhile Soviet Union. The Salyut 1, which went into orbit in 1971, was actually a combination of the Almaz and Soyuz spacecraft systems. While the Almaz was originally designed for space military use, and repurposed for the civilian Salyut space station, the Soyuz spacecraft was used to ferry cosmonauts from Earth to the station, and back. The 45-feet Salyut 1 comprised three main compartments that housed dining and recreation areas, food and water storage, a toilet, control stations, exercise equipment, and a science lab. The Salyut 1 was an epoch-making event during the Space Race, to which the US responded by placing its own first space station – Skylab 1 – in orbit in 1973. The development and launch of the two space stations by the two superpowers of the time, brought into view the limitless boundaries of space technology, culminating in the birth of the ISS.
In 1984, President Ronald Reagan proposed that the US, in cooperation with other countries, build a permanently inhabited space station. To help with the enormous costs of this project ($3 billion is the current cost of running the ISS every year), the US signed a cooperative effort with 14 other nations (Canada, Japan, Brazil; and the European Space Agency, involving the UK, France, Germany, Belgium, Italy, the Netherlands, Denmark, Norway, Spain, Switzerland, and Sweden).
ISS-spotting
All you need to know
The ISS is a very good reflector of sunlight. It travels at a speed of 28,000 kmph, taking 90 minutes to circumnavigate the Earth
NASA has a ‘Spot the Station’ website (spotthestation.nasa.gov), which tells you exactly when the ISS will be overhead and in which direction to look
Bharatiya Antariksha Station
What we know *
ISRO’s Bharatiya Antariksha Station is a planned modular mission, which endeavours to go into orbit by 2035
The first module is expected to be launched on an LVM3 launch vehicle by 2028
* Based on media reports