ISRO’s launch of 104 satellites – World Record – Facts

The Indian Space Research Organization (ISRO) launched a world-record-shattering 104 satellites in one go, breaking the previous record of 37 satellites, held by Russia’s DNEPR. Indians and space enthusiasts all over the world should be proud of ISRO’s launch of 104 satellites in a single mission as it takes us a step closer to a more affordable and democratized presence in the low-earth orbit.

The PSLV-XL - C37 moments before lift-off
The PSLV-XL – C37 moments before lift-off from Satish Dhawan Space Centre, Sriharikota.

How were these 104 satellites launched?

The Launch Vehicle

The Indian Space Agency, ISRO, uses two launch vehicles to inject satellites into orbits. The PSLV (Polar Satellite Launch Vehicle) is used for missions where satellites are to be launched into Low-earth and Sun-synchronous orbits at altitudes ranging from 160 to 2000kms. Whereas, the GSLV (Geosynchronous Satellite Launch Vehicle) is used to launch satellites into the geosynchronous orbit with altitudes reaching as high as 35000kms.

PSLV - C37 - launch vehicle
Polar satellite launch vehicle – XL variant with the six additional strap-on motors at the base

ISRO’s launch of 104 satellites was made possible by the PSLV-XL, a slightly upgraded version of the PSLV with six strap-on motors carrying 12 tons of extra propellant fuel each. The XL version of the PSLV was used to achieve a lift-off mass of 320 tons to accommodate the 1378 kilograms of payload (satellites).

The PSLV is dubbed as the Workhorse of ISRO. It has been in use for 23 years, and this was its 39th mission. Notably, it has successfully launched a whopping 226 satellites into orbit. Accordingly, these laurels have earned the PSLV a reputation as one of the most reliable launch vehicles in the world. Some of its most notable missions were the Chandrayaan 1 mission (India’s mission to the moon) and the Mars Orbiter mission.

The satellites

The primary payload for this mission was the Cartosat – 2D, a satellite from the Indian indigenous satellite series, Cartosat, used for earth observation. Two more Indian nanosatellites, INS-1A and INS-1B, were also launched.

The remaining 101 satellites were from six different countries.

A launch vehicle’s ability to carry satellites depends on

  • the size of the vehicle
  • the payload capacity of the vehicle and
  • payload stacking configurations used to arrange the satellites.

The high number of satellites on this mission was because most of these satellites were nanosatellites. Generally speaking, these nanosatellites are light and small. Usually, nano-satellites are launched in ‘containers’ which gets ejected first and then fires the nano-satellites into their respective orbits. But in this mission, each satellite was injected independently from the launch vehicle, indicating the use of an intuitive stacking configuration.

The mission

The 104 satellites piggybacked on the PSLV and entered the intended orbit in about 16 minutes after lift-off. Then. in the following 12 minutes, all 104 satellites were injected into orbit in a predetermined sequence beginning with the Cartosat-2D, followed by the INS-1A and INS-1B. After injection, the two solar arrays of the Cartosat 2D had deployed automatically. After a few days, the satellite will start providing remote sensing services using its panchromatic (black and white) and multispectral (color) cameras.

What are the uses of these satellites?

The Cartosat series of 6 satellites are a part of the Indian Remote Sensing Program. They are used for the creation of land maps, road network monitoring, coastal land use and regulation, water distribution and various other geographical information system applications.

Cartosat 2D ISRO PSLV-C37 payload
Cartosat 2D

Out of the 96 satellites owned by America, 88 belong to Planet Inc., a company based in California. These 88 nanosatellites are called Doves and will form a constellation to provide real-time high-resolution images of the earth.

Dove - ISRO PSLV-C37 payload
Dove Satellite

The PEASSS (Piezo Electric Assisted Smart Satellite Structure) satellite carries piezoelectric materials and next-generation sensors. For the most part, its primary purpose is to study power generation and pointing accuracy in space.

PEASSS - ISRO PSLV-C37 payload

DIDO, designed by an Israeli-Swiss company SpacePharma consists of a miniaturized lab for micro-gravity research on biological and chemical experiments.

DIDO 1 - ISRO PSLV-C37 payload

The remaining satellites have applications like equipment testing and earth imaging.

Why is ISRO’s launch of 104 satellites a landmark and what lies ahead for ISRO?

ISRO’s Mars mission, which initially faced criticism from domestic as well as international avenues, was what Indians like me fondly like to call, a masterstroke. In terms of technical advancement and sending out a message. It helped ISRO build reliability. Moreover, it helped the Indian Space Program demonstrate to the world that they are here and they are capable.

ISRO has repeatedly displayed its ability to reliably execute satellite launches in the low-earth orbit at affordable rates. As a result, they have been able to net satellite launch deals with major countries and corporations. And that has consequently helped them report a revenue of more than ₹1,860.71 crore (US$280 million) for the year 2014.

However, ISRO’s low fee for deploying satellites in Low Earth Orbit is because the PSLV has a small payload capacity. It can carry only 3800 kg of payload. That is less when compared to launch vehicles like the Falcon 9 (22,800kgs) and H-IIA (more than 10,000kgs).

Hence, at the moment, the niche market that ISRO is trying to capture involves small, lightweight and cheap satellites. Be that as it may, to truly rise and compete against heavyweights like SpaceX, Ariane, and Proton and win a large chunk of the $300 billion global space industry, India needs to develop its GSLV series of launch vehicles.

The indigenous Geosynchronous Satellite Launch Vehicle has suffered numerous setbacks for more than a decade. Not to mention the fact that it currently has only two successful launches using the home-built cryogenic engine to its name.

But after a 23% increase in its budget this year and with the success of missions in the Low Earth Orbit category, ISRO seems to be on the right track towards developing its GSLV-Mk III launch vehicle and offering a low-cost alternative for deploying heavier satellites.

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