EOS (Earth Observation Satellite) missions are designed to deliver high-value data for monitoring Earth’s surface, atmosphere, and dynamic processes from space. These satellites operate in carefully selected orbits, often Sun-synchronous, to ensure consistent lighting conditions and repeat coverage. This allows for precise comparison of changes over time and supports long-term observation continuity. The EOS series plays a critical role in advancing Earth science, national security, environmental monitoring, and disaster response capabilities.

The payload aboard EOS missions typically consists of advanced remote sensing instruments capable of capturing detailed imagery and spectral data across multiple wavelengths. Depending on the mission configuration, these sensors may include optical, multispectral, or hyperspectral imagers. This enables identification of surface materials, vegetation health, land use changes, water quality, and subtle terrain features that are not visible to conventional imaging systems.

EOS satellites are most commonly launched aboard ISRO’s Polar Satellite Launch Vehicle (PSLV), a workhorse rocket optimized for Sun-synchronous and low Earth orbit missions. Launches are conducted from the Satish Dhawan Space Centre on Sriharikota Island, located off India’s southeastern coast. The PSLV’s proven reliability and flexibility make it the primary launch vehicle for Earth observation missions in this class.

The EOS program is developed and launched by the Indian Space Research Organisation, with mission commercialization and customer interfacing often handled by NewSpace India Limited. This structure allows EOS missions to support a mix of civilian, scientific, and strategic users while maintaining continuity across satellite generations.

PSLV-DL

The Polar Satellite Launch Vehicle - DL (PSLV-DL) is the two side-mounted solid rocket booster configuration of the overall PSLV family of expendable rockets flown by the Indian Space Research Organisation (ISRO).

It was built to fill the payload launch gap in capabilities between the PSLV-Core Alone (no side-mounted solid rocket boosters) and PSLV-QL (four boosters).

The rocket also reduces the cost of science and defence mission launches.

Its first flight occurred on January 24th, 2019 when it took the Microsat-R Earth observation satellite to space for the Indian Department of Defence.

The rocket uses a mixture of solid and liquid propellant stages to get to orbit. The first stage, also called the core, is a solid propellant rocket, and the two side-mounted solid propellant boosters are bolted to it.

A liquid fueled second stage then takes over, followed by a third stage that is powered by solid propellant.

A liquid fueled fourth stage serves as the final part of the rocket. The engines on this stage are restartable to place satellites into their proper orbits.

Image: PSLV-DL. Credit: ISRO

Satish Dhawan Space Centre or Sriharikota Range is a rocket launch center operated by the Indian Space Research Organisation. It is located in Sriharikota in Andhra Pradesh.

Chosen for its remote location, the center became operational in 1971 and hosted its first launch that year for a suborbital mission.

The first orbital launch took place on August 10, 1979.

The spaceport received its current name in 2005 when it was named in honor of Satish Dhawan, the former head of the Indian Space Research Organisation.

The facility has two launch pads and will be the base of India's upcoming human spaceflight program.

Image: ISRO