By R Anil Kumar
Bengaluru, December 23. The Indian Space Research Organisation (ISRO), has announced the drafting of its first ‘POEM’ (PSLV Orbital Experimental Module) specifically aimed at studying how life functions in space. This initiative, which is part of a broader effort to explore biological experiments in microgravity, will utilize the PSLV’s final stage, traditionally discarded as space debris, as a stable platform for scientific research.
India for the very first time is flying biological experiments into space using a homegrown rocket. The next launch of the Polar Satellite Launch Vehicle (PSLV) will see not one, but three biological experiments with living cells being rocketed into space. Keeping living things alive in the hostile near vacuum of space is a hugely challenging task.
India will fly living biological material from plants such as spinach, cowpea, and gut bacteria – three different experiments are being planned to be flown onboard the PSLV Orbital Experimental Module-4 (POEM-4).
The POEM platform is designed to conduct in-orbit experiments by repurposing the Polar Satellite Launch Vehicle’s (PSLV) PS4 stage. This allows for a more sustainable approach to space exploration by minimizing space debris while providing a valuable resource for scientific inquiry.
The upcoming missions under POEM will include experiments focusing on biological studies, such as the effects of microgravity on spinach cells.
This research aims to enhance understanding of life processes in space, which is crucial for future long-duration missions and potential human habitation beyond Earth.
POEM features advanced systems for navigation and control, enabling it to maintain stability in orbit. It is equipped with solar panels for power and various sensors to ensure precise orientation and operation during experiments.
ISRO’s initiative fosters collaboration between various stakeholders, including start-ups and academic institutions. By opening up access to this platform, ISRO aims to create a robust ecosystem that supports diverse scientific endeavours in space.
The success of the initial missions under POEM could pave the way for more complex experiments and technology demonstrations, further enhancing India’s capabilities in space research and exploration.
PS4-Orbital Experiment Module, designated as POEM, refers to the usage of the spent fourth stage of the Polar Synchronous Launch Vehicle (PSLV).
It provides an opportunity for the scientific community to carry out certain in-orbit microgravity experiments for an extended duration of up to three months using the POEM platform, which otherwise would end up as space debris immediately after the mission objective of injecting the primary payloads of the mission.
Such experimental payloads serve as precursor experiments to validate various proof-of-concept and enabling technologies for future missions.
PSLV-C60 SpaDeX mission is the fourth POEM Mission (in short POEM-4) in the series. A total of 24 payloads will be flown in this POEM-4 mission, of which 14 payloads are from ISRO/DOS centres and 10 payloads are from various Non-Government Entities (NGEs) comprising Academia and Start-ups that have been received through IN-SPACe.
This is a significant three-fold increase in the capacity of POEM as compared with the previous POEM-3 platform, wherein it had hosted only eight payloads. The following are the highlights of the 24 POEM-4 Payloads.
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R&D Payloads from ISRO/DOS
The 14 ISRO/DOS payloads from various ISRO centres and units consist of 5 payloads from Vikram Sarabhai Space Centre (VSSC, Thiruvananthapuram), 4 payloads from Space Physics Laboratory (SPL-VSSC), 3 payloads from ISRO Inertial Systems Unit (IISU-VSSC), 1 collaborative payload from SPL and IISU, and 1 payload from the Indian Institute of Space Science and Technology (IIST, Valiamala).
The 14 payloads from ISRO/DOS centres primarily focus on the validation of enabling technologies and proof-of-concepts as precursor experiments for future ISRO missions.
They include robotics experiments such as the Walking Robotic Arm through inch-worm walking from IISU, Debris Capture Robotic Manipulator from VSSC, sensor development such as Gradient Control Reaction Wheel Assembly from IISU, Multi-Sensor Inertial Reference System with in-house gyroscopes from IISU, MEMS-based High Angular Rate Sensor from VSSC, new electronics such as Lead Exempt Experimental System from VSSC, Highly Configurable Onboard Common Controller from SPL, space science experiments from SPL such as Electron Temperature Analyser, IDEA-V2 – suite of electron density, neutral wind and Langmuir probe, PLASDEM software model for ionospheric studies from SPL and IISU, Laser Firing Unit & Laser Initiation Pyro Unit from VSSC, Compact Research Module for Orbital Plant Studies from VSSC, and PILOT-G2 payload from IIST.
Payloads and Experiments form NGEs
The 10 payloads from NGEs consist of the study of various spectra of science and engineering, such as growth of plant callus in space from Amity University (Mumbai), Green Monopropellant-based Propulsion System thrusters from M/s Bellatrix Aerospace (Bengaluru), another Green propulsion (Hydrogen Peroxide) based 1.1 N thruster from M/s Manastu Space Technologies Pvt. Ltd. (Mumbai), generation, capture, and processing of Synthetic Aperture Radar (SAR) images from M/s GalaxEye Space Solutions Pvt. Ltd. (Bengaluru), MEMS-based Inertial Measurement Unit (IMU) sensors and ARM-based microcontrollers for attitude measurement from MIT WPU (Pune), demonstration of operational capability of the onboard UHF transmitter by establishing a reliable communication link with the ISTRAC-ISRO ground station from M/s Nspace Tech (Andhra Pradesh), in-orbit demonstration of SAR in a CubeSat form factor from M/s Piersight Space (Ahmedabad), measurement of growth kinetics of a gut bacterium in space from RV College of Engineering (Bengaluru), providing Amateur Radio Satellite services globally from SJC Institute of Technology (Karnataka) in collaboration with UPARC (Upagraha Amateur Radio Clubsat, URSC-ISRO), and India’s first Artificial Intelligence Lab (AI lab) in space from M/s TakeMe2Space (Hyderabad).
The brief description and functionality of each of the 24 payloads onboard POEM-4 of the PSLV-C60 mission, not listed in order of merit, are provided below:
A. 14 R& D Payloads from ISRO/DOS Centres
- RRM-TD: Walking Robotic Arm
Relocatable Robotic Manipulator-Technology Demonstrator (RRM-TD), also known as the Walking Robotic Arm, is India’s first space robotic manipulator with walking capability, developed by IISU.
It is a 7 Degree of Freedom (DoF) robotic arm that will perform re-location through inch-worm walking to defined targets on the POEM-4 platform.
This experiment will demonstrate a large workspace for in-orbit servicing with robotic manipulators comprising indigenous robotic joints and arm controllers, a grappling mechanism and standardised adaptor with power and data transfer, cameras for eye-in-hand operation, and advanced software architecture with obstacle-aware motion planning and several layers of safety features deployed on a high-compute processor.
The experiment will serve as a precursor technology demonstrator for certain robotic technologies of Bharatiya Antariksh Station (BAS), such as end-on-end walking, microgravity operation of robotic arms, vision-based 6DoF pose estimation, visual inspection of stages, robotic manipulation through visual serving and compliance control, harness-free operation using power and data grappling fixtures, Tele-operation, and Digital Twin.
- Debris Capture Robotic Manipulator
Developed by VSSC, the objective of this experiment is to demonstrate the capturing of tethered debris by a robotic manipulator using visual serving and object motion prediction in the space environment.
It also includes the demonstration of a parallel end-effector for object capture and manipulation. Upon successful demonstration of the first experiment, the robotic manipulator will be capable of capturing free-floating debris and refuelling tethered and free-floating spacecraft in future POEM missions.
- Reaction Wheel Assembly (RWA)
The payload is developed by IISU. The objective of the payload is to study the attitude stabilisation of the POEM platform.
It consists of three Reaction Wheels of 0.02 Nm torque and 5 Nms (at 10,000 Rotations per minute) momentum storage capacity, and three independent FPGA-based MIL-STD-1553B interface automotive-grade Wheel Drive Electronics (WDE) integral to the wheels.
The Wheel Drive Electronics module for POEM-4 consists of a single PCB containing Brushless DC motor (BLDC) control circuits, FPGAs, and secondary power management ICs.
- Multi-Sensor Inertial Reference System (MIRS)
The MIRS payload is developed by IISU. The objectives of the payload are technology demonstration and performance evaluation of newly developed miniaturised inertial sensors in space.
The sensors include ISRO Coriolis Resonating Gyro-Digital (ICRG-D), Tuning Fork Gyroscopes (TFG), Advanced Geomagnetic Sensors (AGS), and an Electronic Dosimeter.
- Lead Exempt Experimental System (LEXS)
This payload is developed by VSSC in line with the trending shift in the electronics industry towards Restriction of Hazardous Substances (RoHS) components and processes.
In LEXS, a DC-DC Converter is realised using lead-free (RoHS-compliant) components and processes.
The objective is to demonstrate and assess the reliability and functionality of an RoHS-compliant system in a microgravity environment.
- MEMS-based Rate Sensor
MEMS Rate Sensor is developed by VSSC to meet the high angular rates that were likely to be experienced by the Crew Module in the Air-Drop Test, Pad-Abort Test, and CARE missions.
MEMS Rate Sensors have been inducted into the Lead Exempt Experimental System (LEXS) payload in POEM-4.
The primary objectives of the payload are to measure angular rates along three axes, study the sensor’s behaviour in space, and validate its performance with the LEXS payload.
- Payload Common Onboard Computer (P-COC)
P-COC is developed by SPL. It is a highly configurable and programmable onboard controller suitable for interfacing with various types of sensors (passive, active, and smart) and their front-end electronics (FEE) for conducting scientific experiments onboard sounding rockets, the POEM platform, and spacecraft for Earth and planetary missions. In the POEM-4 mission, the P-COC is used to control and operate IDEA-V2 payloads (ENWi, LP, and ETA).
- Electron Temperature Analyser (ETA)
The Electron Temperature Analyser (ETA) instrument is developed by SPL for in-situ measurement of electron temperature and electron density of planetary ionospheres.
ETA measurements onboard POEM-4 will be used to investigate the spatio-temporal variation of electron temperature and electron density in the low-latitude F-region ionosphere due to the plasma fountain effect, and it will help to demonstrate and validate the concept and capability of the instrument.
- Electron Density and Neutral Wind (ENWi)
The ENWi is one part of the IDEA-V2 payload developed by SPL for ionospheric studies.
Two ENWi payloads onboard POEM-4 will measure ion and electron drifts in two perpendicular directions along the orbit. It has two modes – Ion and Electron mode of operations.
In Ion mode, ENWi will monitor ion density, irregularity, and ion drift, while in Electron mode, electron density, irregularity, and electron drift will be measured.
ENWi will also study the generation processes and day-to-day variability of nighttime ionization irregularities/layers using simultaneous measurements of multiple ionospheric parameters and day-to-day variability of the Equatorial Ionization Anomaly.
- Langmuir Probe (LP)
The LP is the other part of the IDEA-V2 payload developed by SPL for ionospheric studies.
The configuration of three cylindrical Langmuir Probes (LPs) inside IDEA-V2 enables various measurements of ionospheric properties, such as electron temperature using 1-LP in sweep mode to derive the electron density, estimating the electric field using a 2-LP configuration, and estimating absolute electron density with a 3-LP configuration.
- Ionosphere TEC Measurement using NavIC (PLASDEM)
This payload is jointly developed by SPL and IISU. The objective is to measure the Plasmaspheric Electron Content and its longitudinal variations using a dual-frequency NavIC receiver onboard POEM-4, primarily over the Indian region (NavIC regional coverage).
It also uses carrier phase measurements from NavIC signals for ionosphere delay/TEC measurement. The plasmasphere of the Earth’s atmosphere is not well-characterized due to a lack of sufficient measurements in the region of ~350 km altitude.
This is one of the first attempts to use an onboard receiver with NavIC L1 and L5 frequencies for ionospheric delay measurement to study the plasmasphere.
- Laser Firing Unit (LFU) and Laser Initiation Pyro Unit (LIP)
This payload, developed by VSSC, demonstrates an in-orbit initiation test of Pyro technique thrusters using a laser-based firing unit, in comparison to conventional electrical firing circuits.
The unit offers reduced power requirements, lower overall weight and size, a reduction in the number of execution modules and package harness, and enhanced safety features.
- Compact Research Module for Orbital Plant Studies (CROPS)
The CROPS payload, developed by VSSC, is envisioned as a multi-phase platform to develop and evolve ISRO’s capabilities for growing and sustaining flora in extraterrestrial environments.
Designed as a fully automated system, a 5 to 7-day experiment is planned to demonstrate seed germination and plant sustenance until the two-leaf stage in a microgravity environment.
The experiment plans to grow eight cowpea seeds in a closed-box environment with active thermal control. Passive measurements, including camera imaging, O2 and CO2 concentrations, relative humidity (RH), temperature, and soil moisture monitoring, are available for plant growth and monitoring.
- PILOT-G2 (GRACE)
The PILOT-G2 payload, developed by IIST, aims to space-qualify certain critical in-house technologies for small satellites. These include the qualification of the CubeSat UHF communication board, designed to ensure secure and efficient reception of commands from ground stations in space, in-orbit reprogramming of FPGA with non-volatile memory over the On-Board Computer (OBC) ensuring adaptability for post-launch updates, and the Geiger-Müller Counter (GMC) payload.
The GMC payload is engineered to detect high-energy radiations, including alpha particles (≥2.5 MeV), beta particles (50-150 keV), and gamma/X-rays (≥40 keV). This payload will help study the space radiation environment and its impact on satellite operations.
B. 10 Payloads from NGEs (Academia and Start-ups)
- Amity Plant Experimental Module in Space (APEMS)
The APEMS payload is developed by Amity University, Mumbai, and is designed to study growth-related changes in plant callus using the ‘Spinacia oleracea’ model under microgravity (space environment) and Earth gravity (natural environment).
Two parallel experiments will be carried out simultaneously—one on POEM-4 in space and one on the ground at Amity University.
The sunlight and nutrients required for the plant callus will be simulated using LEDs inside the module, with nutrients supplied by a gel medium.
If the green callus dies, it changes colour. The coloration and horizontal growth of the plant will be captured by a camera placed on top of the module.
Additionally, pressure, humidity, and CO2 sensors are integrated into the imaging and sensor unit of the payload.
The experiment’s outcome will provide insights into how higher plants sense the direction of gravity and light, and ameliorate itself to respond, to gravitational stress, and regulate their direction of growth, a basic need for boosting plant growth on Earth and during prolonged spaceflight missions.
- BGS ARPIT (Amateur Radio Payload for Information Transmission)
The BGS ARPIT payload is developed by SJC Institute of Technology, Karnataka.
It is a multimode message transmitter payload that can transmit audio, text, and image messages from a satellite to the ground using FM modulation and the VHF band.
It is designed to provide amateur radio satellite services globally.
This innovative payload serves as an educational outreach tool, catering to students, start-ups, and the burgeoning Indian space sector while commemorating India’s 75th Independence year.
The payload is realised under a collaborative effort between SJC Institute of Technology and UPARC (Upagraha Amateur Radio Club) at URSC.
- RVSat-1
The RVSat-1 payload is developed by RV College of Engineering, Bengaluru, and aims to perform a microbiological experiment under microgravity conditions in Low Earth Orbit.
RVSat-1 will measure the growth kinetics of a gut bacterium, ‘Bacteroides thetaiotaomicron,’ in space and generate a comprehensive growth curve of the bacterium under space conditions, supplemented with prebiotics, and compare it with Earth-based data.
This experiment provides valuable data for understanding human physiology in space and astronaut health and well-being during crewed missions.
The data collected from the experiment has diverse applications such as the development of effective antibiotics against resistant strains, waste management, recycling and bioremediation processes critical for space exploration.
- Green Propulsion: RUDRA 1.0 HPGP
This payload is developed by Bellatrix Aerospace Pvt. Ltd., Bengaluru.
RUDRA 1.0 HPGP is an enhanced version of the RUDRA 0.3 HPGP payload flown in POEM-3. It delivers a nominal thrust of 1 N with a specific impulse of 220 seconds.
The primary objectives of the RUDRA 1.0 HPGP payload are to demonstrate a high-performance Green Propulsion System, sustain steady-state thruster firing for a minimum of 50 seconds, and monitor the thermal profile of the propulsion system.
The payload is completely assembled and packaged in a compact 3U form factor. It comprises an in-house-developed Propellant Tank Assembly (with an indigenous diaphragm), a Thrust Chamber Assembly, Bellatrix Proprietary Green Monopropellant, Bellatrix Proprietary High-Performance Catalyst, a Universal Propulsion Control Unit (UPCU), and an in-house-developed Flow Control Valve.
The package is thermally stable and will operate in both Pulsed Mode and Steady State Mode.
- Green Propulsion Thruster: VYOM-2U
The VYOM-2U payload is developed by Manastu Space Technologies Private Limited, Mumbai.
The payload aims to demonstrate a thruster based on monopropellant, formulated as a blend of hydrogen peroxide and in-house additives, with the goal of providing a safer and higher-performing alternative to hydrazine for space applications.
The Hydrogen Peroxide-based thruster is designed with a thrust range of 1.1 N, a specific impulse of >250 seconds, a total impulse of >1200 Ns, and a maximum continuous firing time of 1000 seconds.
- SAR Imaging Demonstration Payload (GLX-SQ)
The GLX-SQ payload is developed by GalaxEye Space Solutions Private Limited, Bengaluru. This payload demonstrates the generation, capture, and processing of Synthetic Aperture Radar (SAR) images in a space environment.
The payload aims to complete image processing and compression in under 10 minutes, reducing 400 MB of raw data to less than 1.5 MB.
By showcasing the effective combination of hardware and software components, this technology demonstration mission lays the groundwork for future SAR + EO missions, advancing the field of remote sensing with innovations.
- Varuna
The Varuna payload is developed by Piersight Space, Ahmedabad. It is an in-orbit demonstration of a Synthetic Aperture Radar (SAR) in a CubeSat form factor. Varuna is equipped with seven advanced subsystems, engineered for optimal performance.
The objectives of the Varuna payload are to deploy and verify the performance of an indigenously developed reflectarray antenna in orbit, test various subsystems of SAR, including the Software-Defined Radar and Radio (SDRR), Solid State Power Amplifier (SSPA), Reflectarray Antenna and Feed, Reflectarray Deployable Mechanisms, and qualify the X-Band Radio for data downlink.
This mission marks initial step towards establishing a constellation of SAR and Automatic Identification System (AIS) satellites, aiming to provide persistent, near real-time monitoring of all human and industrial activity at sea.
- Swetchasat
The Swetchasat payload is developed by Nspace Tech, Andhra Pradesh. The primary aim of the payload is to demonstrate the operational capability of the onboard UHF transmitter by establishing a reliable communication link with the ISRO Telemetry and Tracking Command (ISTRAC) ground station.
The payload functions in two modes: storage mode for environmental data collection and transmission mode for telemetry downlink.
It provides comprehensive monitoring of ionospheric parameters. Designed for advanced space missions, the 1U form-factor payload integrates a UHF transmitter tailored for downlink-only communication, operating within the UHF amateur bands (435–438 MHz).
The Electrical Power System, environmental sensor board, communication module, payload chassis, and antenna are all indigenously designed and developed by Nspace Tech.
- MEMS-based Inertial Measurement Unit: STeRG-P1.0
The STeRG-P1.0 payload is developed by MIT WPU, Pune. This payload is designed to test and analyse the performance of four commercial-off-the-shelf (COTS) MEMS-based 9-axis IMU sensors and ARM-based microcontrollers for attitude determination and efficient data processing.
The payload incorporates innovative data filtration techniques for improved accuracy, as well as high-resolution data acquisition and storage techniques.
- MOI-TD
The MOI-TD payload is a technology demonstrator AI lab in space, developed by TakeMe2Space, Hyderabad. The mission demonstrates real-time data processing for Earth observation.
The demonstration involves the in-orbit uplink of three Machine Learning (ML) models, in-orbit computation, and downlinking of inferences.
The mission also characterises subsystems such as Air Torquer, Magnetorquer, Reaction Wheel, Sun Sensor, Spectral Sensor, Camera, Onboard Computer (OBC), and Flexible Solar Cells. Custom AI-based applications are uploaded from the ground station to MOI-TD, and post-execution, the results are downlinked to the ground station.
AI techniques will be used to detect and capture daylight and nighttime Earth pictures with optimal sharpness and to process the camera feed in real time.
(Images Source: ISRO)
