Aditya-L1

Aditya-L1

Aditya-L1 in deployed configuration
Mission type	Solar observation
Operator	ISRO
COSPAR ID	{{#property:P247}}
Website	www.isro.gov.in/Aditya_L1.html
Mission duration	5.2 years (planned) 2 years, 11 months and 6 days (elapsed)
Spacecraft properties
Spacecraft	PSLV-XL/C-57
Spacecraft type	PSLV
Bus	I-1K
Manufacturer	ISRO / IUCAA / IIA
Launch mass	1,475 kg (3,252 lb)
Payload mass	244 kg (538 lb)
Start of mission
Launch date	2 September 2023 (2023-09-02), 11:50 IST (06:20 UTC)
Rocket	PSLV-XL
Launch site	Satish Dhawan Space Centre
Contractor	ISRO
Orbital parameters
Reference system	Sun–Earth L1 orbit
Regime	Halo orbit
Period	177.86 days
Epoch	January 2024 (planned)
Mission Insignia

Aditya-L1 (/ɑːd̪it̪jə/) is a coronagraphy spacecraft to study the solar atmosphere, designed and developed by the Indian Space Research Organisation (ISRO) and various other Indian research institutes. It will be orbiting at about 1.5 million km from Earth in a halo orbit around the L1 Lagrange point between the Earth and the Sun where it will study the solar atmosphere, solar magnetic storms, and their impact on the environment around the Earth.

It is the first Indian mission dedicated to observing the Sun. Nigar Shaji is the project's director. Aditya-L1 was launched aboard the PSLV C57 at 11:50 IST on 2 September 2023, ten days after the successful landing of ISRO's Moon mission, Chandrayaan-3. It successfully achieved its intended orbit nearly an hour later, and separated from its fourth stage at 12:57 IST. It is projected to reach its designated orbit at the L1 point approximately 127 days after its launch.

Science objectives

The main objectives of Aditya L1 are:

• To observe the dynamics of the Sun's chromosphere and corona:
  • To study chromospheric and coronal heating, the physics of partially ionised plasma, of coronal mass ejections (CMEs) and their origins, of the coronal magnetic field and heat transfer mechanisms, and flare exchanges
• To observe of the physical particle environment around its position
• To determine the sequence of processes in multiple layers below the corona that lead to solar eruptions
• To study space weather, and the origin, composition and dynamics of solar wind

History

Aditya-L1 in stowed configuration

Aditya-L1 in deployed configuration

Aditya was conceptualised in January 2008 by the Advisory Committee for Space Sciences (ADCOS). It was initially envisaged as a small 400 kg (880 lb) satellite in a Low Earth Orbit (800 km) with a coronagraph to study the solar corona. An experimental budget of ₹3 crore was allocated for the financial year 2016–2017. The scope of the mission has since been expanded and it became a comprehensive solar and space environment observatory to be placed at Lagrange point L1, hence the mission was renamed "Aditya-L1". As of July 2019, the mission has an allocated cost of ₹378 crores excluding launch costs.

Naming

"Aditya" is named after Surya and the Adityas, the Hindu deities representing the Sun. The "L1" designation denotes Lagrange point 1, the spacecraft's destination between the Sun and Earth.

Overview

Lagrange points in the Sun–Earth system (not to scale) – a small object at any one of the five points will hold its relative position.

The Aditya-L1 mission will take around 109 Earth days after launch to reach the halo orbit around the L1 point, which is about 1,500,000 km (930,000 mi) from Earth. The spacecraft is planned to remain in the halo orbit for its mission duration while being maintained at a stationkeeping Δv of 0.2–4 m/s per year. The 1,500 kg (3,300 lb) satellite carries seven science payloads with various objectives, including instruments to measure coronal heating, solar wind acceleration, coronal magnetometry, origin and monitoring of near-UV solar radiation (which drives Earth's upper atmospheric dynamics and global climate), coupling of the solar photosphere to the chromosphere and corona, and in-situ characterisations of the space environment around Earth by measuring energetic particle fluxes and magnetic fields of the solar wind, and solar magnetic storms.

Aditya-L1 will provide observations of the sun's photosphere, chromosphere and corona. Its scientific payloads must be placed outside the interference from the Earth's magnetic field and hence could not have been useful in the low Earth orbit as proposed in the original Aditya mission concept.

One of the major unsolved problems in the field of solar physics is coronal heating. The upper atmosphere of the Sun has a temperature of 1,000,000 K (1,000,000 °C; 1,800,000 °F) whereas the lower atmosphere is just 6,000 K (5,730 °C; 10,340 °F). In addition, it is not understood exactly how the Sun's radiation affects the dynamics of the Earth's atmosphere on a shorter as well as a longer time scale. The mission will obtain near-simultaneous images of the different layers of the Sun's atmosphere, which will reveal the ways in which energy is channeled and transferred from one layer to another. Thus, the Aditya-L1 mission will enable a comprehensive understanding of the dynamical processes of the Sun and address some of the outstanding problems in solar physics and heliophysics.

Payloads

The instruments of Aditya-L1 are tuned to observe the solar atmosphere, mainly the chromosphere and corona. In-situ instruments will observe the local environment at L1. There are seven payloads on-board, with four for remote sensing of the Sun and three for in-situ observation. The payloads have been developed by different laboratories in the country with close collaborations of various ISRO centres.

Type	Sl.No	Payload	Capability	Laboratories
Remote Sensing Payloads	1	Visible Emission Line Coronagraph (VELC)	Corona Imaging and spectroscopy	Indian Institute of Astrophysics, Bangalore
	2	Solar Ultraviolet Imaging Telescope (SUIT)	Photosphere and chromosphere imaging-narrow and broadband	Inter University Centre for Astronomy & Astrophysics, Pune
	3	Solar Low Energy X-ray Spectrometer (SoLEXS)	Soft X-ray spectrometer: Sun-as-a-star observation	U R Rao Satellite Centre, Bangalore
	4	High Energy L1 Orbiting X-ray Spectrometer(HEL1OS)	Hard X-ray spectrometer: Sun-as-a-star observation
In-situ Payloads	5	Aditya Solar wind Particle Experiment (ASPEX)	Solar wind and Particle analyzer: Protons and heavier ions with directions	Physical Research Laboratory, Ahmedabad
	6	Plasma Analyser Package For Aditya (PAPA)	Solar wind and Particle Analyzer: Electrons and Heavier Ions with directions	Space Physics Laboratory, Vikram Sarabhai Space Centre, Thiruvananthapuram
	7	Advanced Tri-axial High Resolution Digital Magnetometers	In-situ magnetic field (Bx, By and Bz).	Laboratory for Electro Optics Systems, Bangalore

Mission Profile

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Flight Sequence of PSLV-C57

Launch

On 2 September 2023, at 11:50 IST, the Polar Satellite Launch Vehicle (PSLV-C57) accomplished a successful launch of the Aditya-L1 from the Second Launch Pad of the Satish Dhawan Space Centre (SDSC) located in Sriharikota.

Aditya-L1, following a flight duration of 63 minutes and 20 seconds, achieved a successful injection into an elliptical orbit around the Earth at 12:54 IST.

Aditya-L1 is scheduled to undergo a series of four Earth-bound orbital maneuvres prior to its injection to a transfer orbit towards the L1 Lagrange point. It is projected to reach its designated orbit at the L1 point approximately 127 days after its launch.

Orbit raising burns

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Trajectory of PSLV-C57/Aditya L1 Mission

First orbit raising burn

On 3 September 2023, the Aditya-L1 performed its first Earth-bound maneuver, raising its orbit to a 245 km (152 mi) into 22,459 km (13,955 mi) orbit.

Second orbit raising burn

On 5 September 2023, Aditya-L1 performed its second Earth-bound maneuver, raising its orbit to a 282 km (175 mi) into 40,225 km (24,995 mi) orbit.

Third orbit raising burn

On 10 September 2023, Aditya-L1 performed its third Earth-bound maneuver, raising its orbit to a 296 km (184 mi) into 71,767 km (44,594 mi) orbit.

Fourth orbit raising burn

On 15 September 2023, Aditya-L1 performed its fourth Earth-bound maneuver, raising its original orbit to a 256 km (159 mi) into 121,973 km (75,791 mi) orbit. This is the last of such maneuvers, being directly followed by the Trans-Lagrangian 1 Injection, bound to take place on 19 September.

Trans-Lagrangian 1 Injection

On 19 September 2023, Aditya-L1 performed its last maneuver around Earth to escape its orbit and headed towards the Lagrange 1 point. It will take at least 4 months to further reach its destination, 1.5 million kilometers away.

On 30 September 2023, Aditya-L1 had escaped the Earth’s sphere of influence and is en route to the Lagrange 1 point.

Mission stages and maneuvers

Stage and Sequence	Date/Time	Time (IST)	Periapsis	Apoapsis	Orbital Period	Ref.
Launch
Earth Orbit Insertion	2 September 2023	12:54 p.m	235 km (146 mi)	19,500 km (12,100 mi)	22 hours, 46 minutes
Earth Bound Maneuvers
Earth Bound Maneuver 1	3 September 2023	11:40 a.m.	245 km (152 mi)	22,459 km (13,955 mi)	39 hours, 20 minutes
Earth Bound Maneuver 2	5 September 2023	3:00 a.m	282 km (175 mi)	40,225 km (24,995 mi)	4 days, 23 hours and 30 minutes
Earth Bound Maneuver 3	10 September 2023	2:30 am	296 km (184 mi)	71,767 km (44,594 mi)	4 days, 23 hours and 45 minutes
Earth Bound Maneuver 4	15 September 2023	2:15 am	256 km (159 mi)	121,973 km (75,791 mi)	3 days, 23 hours and 45 minutes
Trans-Lagrangian Point 1 Injection	19 September 2023	2:00 am
Halo orbit injection
Halo orbit insertion	January 2024

Team

• Nigar Shaji - Project director
• Sankarasubramanian K - Principal scientist of the mission

See also

• Lagrange point
• Solar space missions
• Solar Orbiter
• Parker Solar Probe
• ISRO

External links

• ISRO page for Aditya-L1