by Prasad Ganti
India’s space agency ISRO recently launched a rocket with one hundred and four satellites as payload and released each satellite in succession flawlessly into the intended orbit. Apart from setting a record, some trends became apparent to my mind.
India’s proven launch vehicle PSLV (Polar Satellite Launch Vehicle) carries routine payloads to low earth orbits, a few hundred miles above us. It has carried a lot of satellites belonging to different organizations and countries across the world in the past. The large number of satellites carried recently does not imply a heavier payload. One ISRO’s Cartosat-2 Series Satellite was big and weighed about 714 kg. Two others also belonging to ISRO were Nano Satellite-1 (INS-1) weighing 8.4 kg and INS-2 weighing 9.7 kg and the rest of them were smaller. In fact, the smaller ones were accommodated after some spare capacity in terms of space and weight was found.
Of this bulk payload of small satellites, also called cubesats or nano satellites, ninety six of them belonged to the U.S. based Earth-observing company Planet. Measuring only twelve inches long by four inches wide by four inches high, these tiny satellites, also called Doves, will allow the company to image the entire Earth every day.
The rise of cubesats is amazing. It is democratizing the design, building and launching of satellites. A college project can now consist of designing and building such a satellite. With the growth in complexity and the fall in cost of electronics and sensors, such satellites are becoming commodities. Standardizing the dimensions of such satellites makes it easier to load into launch vehicles and releasing them from it. Something akin to containerization of the shipping industry which led to a dramatic drop in shipping costs across the globe.
The launch of such a large number of satellites required a specialized release strategy involving three stages. In fact, the design of the release adapter was the hallmark of this launch. The three larger satellites belonging to India were deployed first “axially along the vehicle,” followed by eighty one of the nanosats, released in a radial direction away from the vehicle. Finally, the last twenty nanosats successfully separated in a different sequence.
Although the cost of launching a satellite is significant, they are dropping fast. NASA and the other western powers are not the only game in the town anymore. Even they are contracting with low cost countries like India to do the launches. It is said that the engineers in India are paid lower which leads to lower costs. But that is an oversimplified explanation. Technology maturity comes with failures over time and with experience. Besides, these engineers work in a democracy with free markets. No one works for a pittance for the sake of “our beloved leader”. Same way we don’t pay our baby sitters more than what the markets and laws demand.
The smaller companies, countries and universities are now able to have their satellites up in space. Anytime such proliferation occurs for short life cycle devices, it invariably leads to junk. Like mobile phones or tablets or desktop or laptop computers. Space junk will be a serious problem in the future, if it is not already one. There may be a business model to just clean up space garbage!
India’s heavier and higher orbit launcher GSLV (Geosynchronous Satellite Launch Vehicle) is for launching the heavier communication satellites into much higher geosynchronous orbits where they appear to be stationary from a point on Earth. GSLV is still maturing. The current model Mark 2 uses indigenously developed cryogenic engines to launch about 2 tons of payload. Mark 3 for launching 4 tons of payloads is slated for launch in a few months. Setting the stage for a manned spaceflight in near future.
Miniaturizing satellites and launching multiple of them seems to be the mantra for increasing space based applications.