Minimize EMISAT

EMISAT (Electromagnetic Intelligence-gathering Satellite)

EMISAT is a minisatellite with a mass of 436 kg designed and developed at ISRO (Indian Space Research Organization) for India's DRDO (Defence Research and Development Organization). The spacecraft is based around the IMS-2 (Indian Mini Satellite-2) bus with solar panels providing 800 W of power for the spacecraft. DRDO is the operator of the EMISAT mission. 1) 2)

Its mission is officially stated as "electromagnetic spectrum measurement". It is understood that EMISAT will be used for ELINT (Electronic Intelligence). The satellite likely carries Kautilya, an ELINT package that India has been developing since at least 2014. EMISat carries instrumentation to detect, locate and characterize electromagnetic signals, such as those transmitted by military radars.


Figure 1: A frame from the live broadcast of the PSLV launch showed EMISat in a clean room before its mounting atop the PSLV (image credit: ISRO/Doordarshan TV)


Launch: On 1 April 2019 (03:27 UTC, or 09:27 IST), India's PSLV-C45 launcher lifted off from SDSC (Satish Dhawan Space Center) SHAR on India's east cost and successfully injected EMISAT and 28 international customer satellites into their designated orbits. This flight marked the first mission of PSLV-QL, a new variant of PSLV with four strap-on motors. 3)


Figure 2: The PSLV-QL lifts off from the Satish Dhawan Space Center on 1 April 2019 (image credit: ISRO)

About 17 minutes and 12 seconds after lift-off, EMISAT was successfully injected into intended sun-synchronous polar orbit of 748 km altitude. A video camera on the fourth stage showed the EMISat satellite, encased in golden insulation, flying away from the rocket over the Indian Ocean.

After the separation of EMISAT, the vehicle's fourth stage engines were restarted twice to place the 28 international customer satellites precisely into a sun-synchronous orbit of 504 km height. The last customer satellite was placed in its designated orbit 1 hour and 55 minutes after lift-off.

About 3 hours after lift-off, the fourth stage (PS4) of the vehicle was moved to a lower circular orbit of 485 km after two restarts to establish it as an orbital platform for carrying out experiments with its three payloads. The PS4 payloads are:

1) AIS ( Automatic Identification System) from ISRO,

2) APRS (Automatic Packet Repeating System) from AMSAT, India and

3) ARPA (Advanced Retarding Potential Analyzer) for ionospheric studies from Indian Institute of Space Science and Technology.

The objective of the PS4 mission is to demonstrate that the spent stage can host attached payloads in orbit for up to six months after launch. To facilitate this, the PS4 will fly with solar panels for the first time, providing power beyond the limitations of the upper stage's own batteries.

Orbit of EMISAT: Sun-synchronous orbit, altitude of 748 km, inclination of 98.4º.

Orbit of the 28 secondary payloads: Sun-synchronous orbit of 504 km altitude and an inclination of 97.5º.

Orbit of the fourth stage (PS4) hosting three payloads; Sun-synchronous orbit of 485 km altitude and an inclination of 98º.

ISRO Chairman Dr K Sivan congratulated the launch vehicle and satellite teams involved in the mission. "Today's PSLV mission was unique in several ways. It was a four strap-on new variant, the vehicle achieved three different orbits and for the first, the PS4 stage, is powered by solar panels," Dr Sivan said. He added that a new PSLV team executed today's mission.


Figure 3: Illustration of the deployed EMISAT (image credit: ISRO)


Secondary payloads on the EMISAT mission

The 28 international customer satellites have a total mass of 220 kg, They are from four countries, namely, Lithuania (2), Spain (1), Switzerland (1) and USA (24). These foreign nanosatellites were launched as part of commercial arrangements. The nanosatellites launched inside spring-loaded modules, and the PSLV commanded the secondary payloads to deploy one-at-a-time over a sequence that concluded just prior to the two-hour mark in the mission (Ref. 2).

• The first nanosatellite to be deployed from the PSLV's fourth stage was AISTECHSAT-3 with a mass of 2.3 kg of the Spanish company Aistech. The AISTECHSAT- 3 nanosatellite is Aistech's second spacecraft to launch into orbit, and will serve as a pathfinder for the company's planned network of satellites providing aviation tracking and remote asset management services.

• A Lithuanian company, named NanoAvionics, had two satellites fastened atop the PSLV, and they separated from the rocket next.

- The first of the NanoAvionics satellites to deploy was M6P, a 6.8 kg nanosatellite that hosts two commercial payloads for SpaceWorks Orbital and Lacuna Space, two companies designing communications and tracking networks using nanosatellites as relay nodes to collect and retransmit data from devices and sensors around the world.

- The other NanoAvionics satellite launched was BlueWalker 1. It will test unspecified "patented technologies" in space for AST & Science of Texas, a U.S.-based smallsat startup company which acquired a controlling interest in NanoAvionics last year, according to company statements.

- NanoAvionics announced in February that it was building three low Earth orbit nanosatellites for AST & Science, the first of which is BlueWalker 1. The three nanosatellites "will be used to test a range of experimental payloads for defense and commercial customers, and will include a Q/V-band satellite for test and evaluation," NanoAvionics said.

- NanoAvionics said it took only one month to build the BlueWalker 1 spacecraft with a mass of 10 kg and integrate its payload. "The BlueWalker 1 mission demonstrates how NanoAvionics' pre-integrated nanosatellite bus enables faster, more responsive approaches for advancing space technology readiness," said Vytenis Buzas, CEO of NanoAvionics.

• The second satellite for Astrocast, a Swiss company aiming to build a network of 64 data relay satellites in low Earth orbit, was also launched aboard the PSLV. The 3U CubeSat Astrocast 0.2 spacecraft with a mass of 3.8 kg joins Astrocast 0.1, which launched on a SpaceX Falcon 9 rocket in December, to demonstrate the company's concept of using nanosatellites to collect and downlink data from weather buoys, wellhead sensors, pollution monitors and other remote stations. Astrocast 02 is meant to blaze a trail for IoT (Internet of Things) applications to be offered by Switzerland's Astrocast venture.

• Planet Labs of San Francisco is launching 20 Flock-4a (Dove) 3U CubeSats, they will join their constellation of more than 100 Earth-imaging satellites. According to Mike Safyan, Planet's vice president of launch, "These Dove satellites aren't solely for replenishment. They're equipped with the latest technology – upgrades to our imaging chain to improve image sharpness, radiometric consistency, and spectral precision – and push the boundaries of what our on-orbit Doves are capable of." Planet sells its imagery to commercial clients and governments, including U.S. intelligence agencies.

- The EMISAT launch on 1 April marked the fifth time Planet has put its satellites on an Indian rocket, making Planet one of the Indian space program's biggest export customers.

- Planet books its rides on PSLV missions with Antrix, the commercial arm of ISRO. For this launch, Planet arranged for its satellites to ride on the PSLV through Spaceflight, a commercial smallsat launch broker based in Seattle,WA.

• Spire Global of San Francisco launched 4 Lemur-2 3U CubeSats, adding to Spire's fleet of more than 70 active nanosatellites tracking ships and collecting atmospheric data that could one day improve the accuracy of weather prediction models.

- NanoRacks has completed their first CubeSat deployment mission on ISRO's (India Space Research Organization) Polar Satellite Launch Vehicle (PSLV-C45) — this mission was brokered on behalf of Spire, which now has four more of their Lemur 3U CubeSats in orbit. 4)

- Notably, this mission included the launch of Spire's 100th Lemur satellite. NanoRacks announced SSO polar orbit launch opportunities after receiving significant demand and strong feedback for the customer support that the company offers. Polar orbit offerings come in addition to NanoRacks' proven success in smallsat deployments, having deployed more than 230 satellites to date.

- This PSLV opportunity was completed in coordination with Berlin-based Astro- und Feinwerktechnik Adlershof GmbH (Astrofein) to manufacture and supply deployers, and the launch opportunity with Antrix Corporation Limited (Antrix), the commercial arm of ISRO.



India's ASAT (Anti-Satellite) test mission called 'Mission Shakti'

The PSLV launch of EMISAT was India's first since the country's military successfully tested an anti-satellite missile on 27 March 2019 , destroying an Indian satellite in orbit roughly 175 miles (282 km) above Earth. 5)

India's test of a satellite kill vehicle shattered the mission's target, named Microsat-R, into countless fragments. Due to the relatively low altitude of the intercept, most of the material is expected to naturally reenter Earth's atmosphere within days or weeks, but some debris ejected into higher orbits from the force of the impact could remain in orbit longer.

Officials from several commercial satellite operators, including Planet, condemned the anti-satellite test. "Space should be used for peaceful purposes, and destroying satellites on orbit severely threatens the long-term stability of the space environment for all space operators," Planet said in a statement. "Planet urges all space-capable nations to respect our orbital commons."

The U.S. Air Force's 18th Space Control Squadron, which detects and catalogs objects in Earth orbit, said in a tweet Friday it is "actively tracking more than 250 pieces of debris associated with (the) Indian ASAT launch" and that the Joint Force Space Component Command is "issuing conjunction notifications to satellite operators as needed to support spaceflight safety."

AGI (Analytical Graphics Inc.) modeled the Indian anti-satellite test, and the company's experts suggested the missile struck the Microsat-R satellite at a relative velocity of nearly 22,000 mph, or 9.8 km/s.

AGI's simulation predicted the collision created approximately 6,500 debris fragments larger than a pea, about 0.5 cm in diameter. Experts said fewer objects were expected to be large enough to be tracked by the U.S. military space surveillance radars, meaning much of the debris would remain undetected until it fell back into Earth's atmosphere.

1) On March 27, 2019 India conducted Mission Shakti, an anti-satellite missile test, from the Dr. A P J Abdul Kalam Island launch complex. This was a technological mission carried out by India's DRDO (Defence Research and Development Organization). The satellite used in the mission was one of India's existing satellites operating in LEO (Low Earth Orbit). The test was fully successful and achieved all parameters as per plans. The test required an extremely high degree of precision and technical capability.

2) The significance of the test is that India has tested and successfully demonstrated its capability to interdict and intercept a satellite in outer space based on complete indigenous technology.

3) With this test, India joins an exclusive group of space faring nations consisting of USA, Russia and China.

Which satellite was used? — The satellite used was an Indian satellite named Microsat-R.

Which Missile/Interceptor was used? — The DRDO's Ballistic Missile Defence interceptor was used, which is part of the ongoing ballistic missile defence program.

There are other ways to demonstrate ASAT capabilities such as "fly-by tests" and Jamming. Why has India used the particular technology of Kinetic Kill? — This is a technology where we have developed capability. Space technologies are constantly evolving. We have used the technology that is appropriate to achieve the objectives set out in this mission.

Does the test create space debris? — The test was done in the lower atmosphere to ensure that there is no space debris. Whatever debris that is generated will decay and fall back onto the earth within weeks.

Why did we do the test?

• India has a long standing and rapidly growing space program. It has expanded rapidly in the last five years. The Mangalyaan Mission to Mars was successfully launched. Thereafter, the government has sanctioned the Gaganyaan Mission which will take Indians to outer space.

• India has undertaken 102 spacecraft missions consisting of communication satellites, earth observation satellites, experimental satellites, navigation satellites, apart from satellites meant for scientific research and exploration, academic studies and other small satellites. India's space program is a critical backbone of India's security, economic and social infrastructure.

• The test was done to verify that India has the capability to safeguard our space assets. It is the Government of India's responsibility to defend the country's interests in outer space.

Why was the test done now? — The tests were done after we had acquired the required degree of confidence to ensure its success, and reflects the intention of the government to enhance India's national security. India has seen an accelerated space development program since 2014.

Is India entering into an arms race in outer space?

• India has no intention of entering into an arms race in outer space. We have always maintained that space must be used only for peaceful purposes. We are against the weaponization of Outer Space and support international efforts to reinforce the safety and security of space based assets.

• India believes that Outer space is the common heritage of humankind and it is the responsibility of all space-faring nations to preserve and promote the benefits flowing from advances made in space technology and its applications for all.

• India is a party to all the major international treaties relating to Outer Space. India already implements a number of Transparency and Confidence Building Measures(TCBMs) – including registering space objects with the UN register, prelaunch notifications, measures in harmony with the UN Space Mitigation Guidelines, participation in Inter Agency Space Debris Coordination (IADC) activities with regard to space debris management, undertaking SOPA (Space Object Proximity Awareness and COLA (Collision Avoidance) Analysis and numerous international cooperation activities, including hosting the UN affiliated Center for Space and Science Technology Education in Asia and Pacific. India has been participating in all sessions of the UN Committee on the Peaceful Uses of Outer Space.

• India supported UNGA resolution 69/32 on No First Placement of Weapons on Outer Space. We see the No First Placement of weapons in outer space as only an interim step and not a substitute for concluding substantive legal measures to ensure the prevention of an arms race in outer space, which should continue to be a priority for the international community.

• India supports the substantive consideration of the issue of Prevention of an Arms Race in Outer Space (PAROS) in the Conference on Disarmament where it has been on the agenda since 1982.

What is the international law on weapons in outer space?

• The principal international Treaty on space is the 1967 Outer Space Treaty. India is a signatory to this treaty, and ratified it in 1982. The Outer Space Treaty prohibits only weapons of mass destruction in outer space, not ordinary weapons.

• India expects to play a role in the future in the drafting of international law on prevention of an arms race in outer space including inter alia on the prevention of the placement of weapons in outer space in its capacity as a major space faring nation with proven space technology.

• India is not in violation of any international law or Treaty to which it is a Party or any national obligation.

Is the test directed against any country?

• The test is not directed against any country. India's space capabilities do not threaten any country and nor are they directed against anyone.

• At the same time, the government is committed to ensuring the country's national security interests and is alert to threats from emerging technologies. The capability achieved through the Anti-Satellite missile test provides credible deterrence against threats to our growing space-based assets from long range missiles, and proliferation in the types and numbers of missiles.

Table 1: Frequently Asked Questions on Mission Shakti, India's Anti-Satellite Missile test conducted on 27 March, 2019 6)



Some statements/reactions to India's ASAT mission

• March 27, 2019: India's Prime Minister Narendra Modi has confirmed that the country has performed a test of an anti-satellite missile successfully striking a target satellite in low Earth orbit. The test is seen by many as extremely irresponsible given the potential for harm to other satellites in low Earth orbit. 7)

- During a television broadcast following the test, Modi confirmed that the country had successfully destroyed a target satellite in low Earth orbit. "Some time ago, our scientists shot down a live satellite 300 kilometers away in space". He described the test as a historic feat for the country stating, "India has made an unprecedented achievement today. India registered its name as a space power."

- Most nations capable of anti-satellite missile development have abandoned in orbit testing due to the potential of what is commonly referred to as the Kessler Effect.

- The Kessler Effect was first described by NASA scientist Donald Kessler in 1978. It proposed a scenario in which the destruction of an orbiting satellite (either by debris or an intentional strike) could cause a cascade of destruction that couldn't be stopped. Once complete, the Earth would be shrouded in a blanket of debris making it impossible to launch or place new satellites.

- Despite the potential for harm, India is not the first nation to complete an in-orbit test of an anti-satellite weapon (ASAT). From the 1960s to the 1980s, both Russia and the United States successfully tested multiple ASAT prototypes. More recently, China completed an ASAT test in 2007, the US destroyed a malfunctioning spy satellite in 2008, and Russia completed as many as three ASAT tests just last year.

• March 29, 2019: The Coalition for Nuclear Disarmament and Peace (CNDP) takes serious note of the dramatic declaration of the Indian Prime Minister, on March 27, early afternoon, claiming, in a nationally televised address, successful testing of an ASAT missile by way of destroying an Indian military Low Earth Orbit (LEO) satellite at an altitude of almost 300 km, over the Bay of Bengal. 8)

- Whatever be the actual military significance of the claimed successful test, it definitely makes the current regional and global scenarios even murkier and constitutes an assault on the ongoing global campaign for demilitarization of the outer space.

- Of course, the United States is the original culprit, which would soon enough be joined in by its the main adversary then - the Soviet Union, and, later, China. The ASAT tests carried out by these countries and India go against the very grain of the Outer Space Treaty of 1967 to which all the said four States are parties. The Treaty in no uncertain terms states as follows: "The States Parties to this Treaty… Recognizing the common interests of all [hu]mankind in the progress of the exploration and use of outer space, Have agreed to the following:... (Article III) ‘State Parties to the Treaty shall carry on activities in the exploration of space and USE OF OUTER SPACE… IN THE INTEREST OF MAINTAINING INTERNATIONAL PEACE AND SECURITY and promoting international cooperation and understanding.' (Article IV) ‘State Parties to the Treaty undertake not to place in orbit around the Earth any objects carrying nuclear weapons ... or STATION WEAPONS IN OUTER SPACE IN ANY OTHER MANNER."

- The open and boisterous entry of India into the so-called 'Star Wars' club, despite self-imposed abstinence by all the other technologically advanced countries, except three, is a wholly regrettable development, more so because ASAT weapons can in no way PROTECT Indian satellites deployed in outer space. Since ASAT weapons can only DESTROY an adversary's satellites, any use of such weapons would be a provocative act that tantamounts to declaration of war.

- Satellites and spacecrafts in outer space can be protected only through mutual agreements by all concerned. In this regard, adoption of the draft treaties on Prevention of an Arms Race in Outer Space (PAROS) and the Prevention of the Placement of Weapons in Outer Space, the Threat or Use of Force against Outer Space Objects (PPWT) that are pending before the Conference on Disarmament attains added importance. The only country opposed to the adoption of PAROS and PPWT is the United States.

• April 2, 2019: NASA administrator Jim Bridenstine has revealed that India's recent anti-satellite (ASAT) missile test has increased the risk of debris impacting with the International Space Station (ISS) by as much as 44%. 9)

- Speaking at a town hall meeting with NASA employees, Bridenstine was asked about India's ASAT missile test, codenamed "Mission Shakti". The test was conducted by the country's Defence Research and Development Organization (DRDO) on March 27, 2019. It destroyed the Microsat-R satellite which had been launched aboard a PSLV rocket earlier this year, a satellite presumably specifically designed to act as a target.

- In his response to the question, Bridenstine revealed that the test had produced around 400 pieces of medium to large pieces of debris, 60 of which are large enough to be tracked by US military assets. Although many of the larger pieces are at a low orbit, at least 24 of them are on a trajectory taking them above the apogee of the International Space Station.

- "That is a terrible, terrible thing, to create an event that sends debris into an apogee that goes above the International Space Station," said Bridenstine. "While the risk went up 44 percent, our astronauts are still safe. The International Space Station is still safe."


1) "India launches EMISAT intelligence-gathering satellite and 28 CubeSats," NASA, 31 March 2019, URL:

2) Stephen Clark, "Indian military satellite, 20 more Planet imaging CubeSats launched by PSLV," Spaceflight Now, 1 April 2019, URL:

3) "PSLV-C45/EMISAT Mission," ISRO, 1 April 2019, URL:

4) Doug Messier, "NanoRacks Completes First CubeSat Mission on India's PSLV, Launches Spire's 100th Satellite," Parabolic Arc, 1 April 2019, URL:

5) Stephen Clark, "Indian military satellite, 20 more Planet imaging CubeSats launched by PSLV," Spaceflight Now, 1 April 2019, URL:

6) Ministry of External Affairs, Government of India, New Delhi, 27 March 2019, URL:

7) Andrew Pearson, "India Shoots Down Satellite Shocking Global Community," Rocket Rundown, CNDP, 27 March 2019, URL:

8) "India: Statement on the Anti-Satellite Missile Test and Prime Minister Declaration," 29 March 2019, URL:

9) "NASA Administrator Reveals India's ASAT Test Increased Risk of ISS Debris Impact by 44%," Rocket Rundown, 2 April 2019, URL:


The information compiled and edited in this article was provided by Herbert J. Kramer from his documentation of: "Observation of the Earth and Its Environment: Survey of Missions and Sensors" (Springer Verlag) as well as many other sources after the publication of the 4th edition in 2002. - Comments and corrections to this article are always welcome for further updates (