EMISAT: India's spy in the sky, 28 other payloads to be launched on ISRO's PSLV-C45 on 1 April

This will be ISRO's first attempt at placing satellites in 3 different orbits in a single launch.

On 1 April, the Indian Space Research Organisation will carry the Indian EMISAT and 29 other satellites and place them in orbit in a special mission.

This will be the first time ISRO attempts to place satellites in three different orbits in a single satellite launch mission — the PSLV-C45/EMISAT mission.

What is EMISAT?

The highlight of the launch on 1 April is EMISAT — a powerful electronic intelligence/surveillance satellite — developed jointly by the Indian Space Research Organisation (ISRO) and DRDO (Defense Research and Development Organisation). For satellite standards, EMISAT is a rather small one weighing in at under 500 kg.

ISRO will likely place EMISAT in a highly elliptical orbit, also called a signature SIGINT orbit, after its launch on the PSLV-QL, a new variant in the PSLV family. This gives satellites the maximum amount of time to record high-resolution signals from a specific area.

EMISAT: Indias spy in the sky, 28 other payloads to be launched on ISROs PSLV-C45 on 1 April

An illustration of ISRO's EMISAT satellite. Image: ISRO/AFC

How does EMISAT work?

EMISAT is modelled after a famous Israeli spy satellite called SARAL (Satellite with ARgos and ALtika). Both these satellites have the SSB-2 bus protocol — the core component for their sharp electronic surveillance capabilities across the length and width of a large country like India.

EMISAT also has a special altimeter (a radar altitude measuring device) called 'AltiKa' that works in the Ka-band microwave region of the spectrum. The electronic surveillance payload of EMISAT was developed under DRDO's project 'KAUTILYA'.

The main capability of EMISAT is in signal intelligence — intercepting signals broadcasted by communication systems, radars, and other electronic systems on the ground from hundred of kilometres away in space. The Ka-band frequency that EMISAT is sensitive to allows the 436-kg EMISAT — India's newest spy in the sky — to scan through ice, rain, coastal zones, land masses, forests and wave heights relatively easily.

As of this month, the EMISAT project has been eight years in the making.

On 1 April, the PSLV-C45 mission will carry it into low-Earth orbit and place it in an orbit at 749 km. Following this, 28 other satellites will also be released at different altitudes.

The PSLV-C40 mission lauching from ISRO's launchpad at Sriharikota. Image: ISRO

The PSLV-C40 mission launching from ISRO's launchpad at Sriharikota. Image: ISRO

Other payloads on the PSLV-C45 mission

Flock 4a Doves: Twenty Earth-imaging CubeSats made by Planet Labs, called the 'Flock 4a' fleet. Planet has placed 219 Flock doves in orbit since 2013 — almost half of them launched in 2017.

Lemur-2: Four CubeSats (3U) by Spire Global, a space-to-cloud analytics company that uses nanosatellites to track aviation, maritime, and weather patterns. The Lemur-2s were built to study and monitor air, marine traffic using remote sensing techniques.

BlueWalker-1: A 6U CubeSat built by AST & Science and Nanoavionics

M6P: A 6U CubeSat by Nanoavionics to test a new (M6P) platform to host Internet of Things (IoT) payloads with space companies SpaceWorks Orbital and Lacuna Space. The 'green' chemical propulsion system on M6P was part of the LituanicaSAT-2 satellite that was launched on the PSLV C38 mission.

Astrocast-2: A 3U CubeSat built by Astrocast, a network of small satellites providing low-cost Internet of Things (IoT) connectivity "to people changing the world", as per their website.

AIStechsat-3 (Danu Pathfinder): A 2U cubesat made by AIStechspace to help with maritime and aeronautical tracking. The CubeSat is a prototype for a larger constellation to deliver Internet of Things (IoT) services for tracking & monitoring in the aviation sector.

Special fourth stage experiment

The fourth stage (PS4) of the PSLV-C43 in this EMISAT mission will act as an orbital platform for research organisations and academic institutes to perform microgravity experiments in. The upcoming mission's PS4 will host three payload experiments:

  1. Automatic Identification System (AIS) from ISRO
  2. Automatic Packet Repeating System (APRS) from AMSAT (Radio Amateur Satellite Corporation), India
  3. Advanced Retarding Potential Analyzer for Ionospheric Studies (ARIS) from Indian Institute of Space Science and Technology (IIST)

ISRO discussed at the start of 2019 their interest in opening up future mission fourth stages to universities and startups to send their microgravity experiments to space for a maximum period of 6 months. The PSLV's PS4 would shelter it from space debris as well as power the experiments for that duration.

ExseedSAT during its developmental phase awaiting a 'bake test' in a thermovac chamber. Image courtesy: Twitter/Sanjay Nekkanti

ExseedSAT during its developmental phase awaiting a 'bake test' in a thermovac chamber. Image courtesy: Twitter/Sanjay Nekkanti

One of the two non-ISRO entities making the most of the opportunity is Exseed Space, which, after becoming the first Indian private company to go to space in the PSLV-C44 mission, will soon also become the second to go to space.

When and where to watch the EMISAT launch live

The PSLV-C45 mission will launch on 1 April aboard a modified version of the PSLV rocket.

The overall flight sequence will take roughly 180 minutes, starting with the launch at 9.30 am ISRO on Monday, 1 April.

A live stream of the launch and separation will be available on DD National's YouTube page or ISRO's website starting 9 am Monday.

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