The Indian Space Research Organisation (ISRO) is preparing to launch its Aspides mission in 2025 to study the mysteries of the Sun’s corona. The Aspides spacecraft will observe the corona to understand the origins of the high temperature of the solar atmosphere and the acceleration of the solar wind.
Origins and Goals of the Aspides Mission
- Aspides stands for “Studying Solar Particle Events and Solar Irradiance”
- Proposed by ISRO in late 2021 and approved in early 2022
- Will be ISRO’s first space weather focused mission
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Key goals
- Understand heating of the corona and acceleration of solar wind
- Study origin, evolution and propagation of Coronal Mass Ejections (CMEs)
- Measure solar radiance fluctuations
Key Payloads and Instruments
- Visible Emission Line Coronagraph (VELC): Will image the corona from 1.05 to 3 solar radii in visible light
- Ultraviolet Imaging Telescope (UVIT): Will image the chromosphere in UV light
- Solar Low-Frequency Radio Spectrometer (SLFRS): Will measure solar radio bursts
- Solar Wind Analyzer (SWAN): Will measure properties of solar wind particles
- X-ray Photometer (XP): Will measure X-ray flux from the Sun
- Magnetometer: Will measure magnetic field in solar wind
Launch Details
- Launch planned for Q3 2025 on GSLV Mk III rocket
- Will be inserted into a halo orbit around Sun-Earth L1 Lagrangian point
- Designed for 5 years of operations
Understanding the Corona’s Mysteries
The key mysteries about the solar corona that Aspides will study:
Extreme Heating of Corona
- Corona is 200-500 times hotter than solar surface, while its atmosphere gets cooler farther from the surface
- Heating mechanisms not fully understood – wave heating and magnetic reconnections play a role
- Aspides observations will help discriminate between theoretical heating models
Acceleration of Solar Wind
- Fast solar wind streams originate from coronal holes, but acceleration mechanisms unclear
- UVIT, SLFRS and SWAN will trace solar wind acceleration regions
Propagation of Coronal Mass Ejections
- CMEs drive space weather effects on Earth – can damage satellites and disrupt power grids
- Aspides will observe their initiation and propagation in corona
Solar Irradiance Variations
- Solar output fluctuations impact Earth’s climate and satellite drag over orbits
- XP will measure total and spectral solar irradiance with high accuracy
Aspides instruments and key parameters
| Instrument | Key Parameters to Measure | Investigation Goals |
| VELC | Visible light corona images from 1.05-3 solar radius | Corona structure dynamics for CME studies |
| UVIT | Chromospheric images in UV bands | Connection between photosphere, chromosphere and corona |
| SLFRS | Radio bursts from sun | Particle acceleration regions for solar wind, CME origins |
| SWAN | Velocity distribution functions of solar wind particles | Solar wind acceleration mechanisms |
| XP | Total and spectral solar irradiance | Solar variability and impact on climate, satellite drag |
| Magnetometer | Magnetic field in solar wind | Mapping CME magnetic structures |
Aspides and Future ISRO Solar Missions
If Aspides meets its mission goals of unraveling mysteries surrounding the corona, it will pave the way for ISRO’s more advanced future solar missions:
- Solar-C: Proposed solar orbiter with ESA collaboration for launch in 2031
- Aditya-L2: Next generation L2 observatory for chromosphere, corona studies
- Aditya-L1: First Indian solar space weather monitoring mission at L1
Recent Developments
- In December 2022, ISRO successfully tested the Visible Emission Line Coronagraph (VELC) payload at ISRO’s VRL lab in India. The tests validated the payload’s imaging performance meet mission requirements.
- In January 2023, the Ultraviolet Imaging Telescope (UVIT) was integrated with the Aspides satellite structure at ISRO Satellite Centre. Post integration tests verified its alignment and performance.
- The spacecraft structure and propulsion system was readied by February 2023. Integration of payloads and tests are underway at satellite center.
- ISRO is building multiple ground stations to support Aspides – New tracking stations were added in Mauritius, Bhutan and Indonesia in 2022-23 timeframe.
- The High Throughput Satellite Communication System crossed an important milestone in Feb 2023, it will form vital communication links for Aspides mission’s high data rates.
- In ASPIN nano-satellite project, all college teams building cube satellite payloads concluded design reviews and started integration & testing of flight hardware in early 2023.
- GSLV Mk3 rocket identified for launch underwent engine testing in Jan 2023. Its cryo stage was tested in February 2023 for validation.
The roadmap from Aspides to these ambitious future missions will cement India’s position at the forefront of global solar physics research, while enhancing indigenous space weather prediction capabilities crucial for the safety of our space assets and critical infrastructure on Earth.
