Explained: What Is ISRO's SSLV-D1 Mission? All About The SSLV Maiden Flight Taking Off On August 7

The SSLV-D1 mission is the first demonstration flight of SSLV, and will launch from Satish Dhawan Space Centre in Sriharikota, at 9:18 am IST on August 7. The primary payload is Microsat 2A or EOS-02.

Left: Small Satellite Launch Vehicle (SSLV). Right: Representative Photo. The maiden flight of SSLV is scheduled to take off on August 7, 2022. The primary payload of SSLV is Microsat 2A. A satellite named AzaadiSAT will also be launched into space as a co-passenger.

Source : ISRO

SSLV-D1 Mission: The maiden flight of India's Small Satellite Launch Vehicle (SSLV) is scheduled to take off on August 7, 2022, the Indian Space Research Organisation (ISRO) announced Monday. 

The mission, called SSLV-D1, is the first demonstration flight of the launch vehicle, and will take off from Satish Dhawan Space Centre in Sriharikota, at 9:18 am IST on August 7. 

The launch of the SSLV-D1/EOS-02 Mission is scheduled for Sunday, August 7, 2022, at 9:18 am (IST) from Satish Dhawan Space Centre (SDSC), Sriharikota. ISRO invites citizens to the Launch View Gallery at SDSC to witness the launch. Registration is open at https://t.co/J9jd8yDs4a pic.twitter.com/rq37VfSfXu

— ISRO (@isro) August 1, 2022

The primary payload of SSLV is an Earth Observation Satellite called Microsat 2A or EOS-02. A satellite named AzaadiSAT will also be launched into space as a co-passenger on India's latest launch vehicle. 

Over the years, ISRO has successfully realised five generations of launch vehicles, namely Satellite Launch Vehicle-3 (SLV-3), Augmented Satellite Launch Vehicle (ASLV), Polar Satellite Launch Vehicle (PSLV), Geosynchronous Satellite Launch Vehicle (GSLV), and GSLV Mark III. These launch vehicles have catered to national developmental needs, and enabled ISRO to develop and master critical technologies related to solid, liquid and cryogenic propulsion systems. 

ISRO developed SSLV to cater to the emerging global small satellite launch services market. SSLV has the capability to launch on demand. 

All About SSLV 

The Small Satellite Launch Vehicle (SSLV) is a three-stage launch vehicle configured with three solid propulsion stages and a terminal stage. A solid propulsion rocket stage uses solid propellants as the fuel. The terminal stage is a liquid propulsion-based Velocity Trimming Module (VTM). 

According to ISRO, SSLV has a diameter of 2.1 metres and a length of 34 metres. The liftoff mass of the launch vehicle is approximately 120 tonnes. The launch vehicle is capable of launching payloads weighing up to 500 kilograms to low-Earth orbit (LEO). 

The key features of SSLV are low cost, flexibility in accommodating multiple satellites, 'launch on demand' feasibility, low turnaround time (the time taken to complete a process), minimal launch infrastructure requirements, and increased production rate from industries. 

Also, SSLV has the minimum launch pad occupancy, which means that integration of the vehicle and subsequent launch can be completed within 24 hours. 

SSLV has multiple satellite mounting options for nanosatellites, micro satellites, and mini satellites. The launch vehicle can carry a single satellite weighing up to 500 kilograms to a 500-kilometre planar orbit. 

SSLV can carry payload weighing up to 300 kilograms to Sun-synchronous orbit (SSO). 

The Velocity Trimming Module (VLT) is equipped with a payload adapter. The first, second, and third stages are known as SS1, SS2, and SS3, respectively. 

According to Gunter's Space Page, the first stage of SSLV is related to the Agni-3 and Agni-5 IRBM (Intermediate-range ballistic missile) motors, but has a new design. 

The satellites will initially be launched atop SSLV from Satish Dhawan Space Centre. However, the third launch may take place from a new launch site being planned on the Indian West coast near Gujarat. 

SSLV will carry Microsat 2A and AzaadiSAT as payloads as part of the SSLV-D1 mission.

All About EOS-02 (Microsat 2A)

Microsat 2A is a small Earth observing satellite developed by ISRO as a test payload for the maiden launch of SSLV. The satellite, also known as EOS-02, is based on Microsat-TD, which was also an Earth observing satellite. It was India's 100th satellite in space, and had the capacity to capture images at night.

Microsat 2A is expected to meet the increasing user demands of cartographic applications at cadastral level, and facilitate urban and rural management, coastal land use and regulation, mapping of utilities, and other geographic information system (GIS) applications, according to Gunter's Space Page. Cartography is the art of drawing maps, and a cadastral survey tracks and shows the boundary lines of privately owned real estate and public land. 

Microsat 2A carries two payloads, namely MWIR (Mid-Wave Infrared) and LWIR (Long-Wave Infrared) cameras.

The mass of Microsat 2A is 142 kilograms. The satellite will be placed into orbit at an altitude of 350 kilometres above sea level. The mission life of Microsat 2A is 10 months. It will be powered by two deployable solar arrays. 

Microsat 2A will be placed into the Sun-synchronous orbit. 

Earlier this year, Dr Jitendra Singh, Union Minister for Science and Technology, said in a written reply to the Rajya Sabha that EOS-02 is a technology demonstration satellite for various new technologies with applications that include agriculture, forestry, geology, miniaturised power electronics, hydrology, and reaction wheels, among others. 

EOS-02 was slated for launch in 2021, but the mission was delayed due to the Covid-19 pandemic.

All About AzaadiSAT

AzaadiSAT is an 11-kilogram satellite built by 750 girl students from 75 schools across India. The satellite, which will be launched into orbit as a co-passenger satellite on SSLV, has long range communication transponders, and selfie cameras that will click pictures of its own solar panels, the Indian National Space Promotion and Authorization Center (IN-SPACe) said in a tweet. IN-SPACe is an independent nodal agency under the Department of Space, Government of India, formed to allow space activities and the usage of department-owned facilities by non-governmental private entities (NGPEs). 

The Azaadisat is a student satellite carrying 75 femto experiments, selfie camera to click pictures of its own solar panels and LoRa (Long Range Communication) transponders.
It is expected to encourage girl students to take up STEM subjects. [3/3]

— IN-SPACe (@INSPACeIND) July 29, 2022

The AzaadiSAT project is part of the Azadi Ka Amrit Mahotsav celebrations. Azadi Ka Amrit Mahotsav is an initiative by the Government of India to celebrate and commemorate 75 years of India's independence. 

AzaadiSAT has a mission life of six months. The project is expected to encourage girl students to take up STEM (Science, Technology, Engineering, and Mathematics) subjects.

The satellite has been developed by Space Kidz India, an aerospace organisation creating young scientists for the country. The AzaadiSAT project is a first-of-its-kind space mission with an 'all women concept' to promote 'Women in STEM', a statement released by Space Kidz India said. 

IN-SPACe and Space Kidz India signed the Memorandum of Understanding (MoU) for AzaadiSAT on June 10.

IN-SPACe wrote in a tweet that 750 girl students from 75 schools across India will be “cheerfully looking at the maiden launch of India's latest launch vehicle SSLV, as it carries their AzaadiSat onboard as a co-passenger”.

Last month, Rifath Sharook, the chief technology officer at Space Kidz India, said on Twitter that the AzaadiSAT is a special mission in which the organisation provided 750 girl students the training to build 75 experimental payloads. 

This is a special mission planned for celebrating India's 75 Years of Independence with Azadi Ka Amrit Mahotsav. In this mission we have selected 750 girl student from 75 government schools from all the Indian states and provided training to build 75 experimental payloads.

— Rifath Shaarook (@rifath_shaarook) July 8, 2022

He further said that the students were provided with components and training to build basic sensors which can measure different space parameters. The experiments are integrated into the satellite and will fly to orbit, he added. The students are also building their own ground station to receive signals from the satellite.

Sharook further wrote that AzaadiSAT will enable low cost access to space in the future.