# IKAROS

> uncrewed Japanese experimental solar sail space probe

**Wikidata**: [Q609059](https://www.wikidata.org/wiki/Q609059)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/IKAROS)  
**Source**: https://4ort.xyz/entity/ikaros

## Summary
IKAROS (Interplanetary Kite-craft Accelerated by Radiation Of the Sun) is an uncrewed Japanese experimental space probe developed by the Japan Aerospace Exploration Agency (JAXA) and the Institute of Space and Astronautical Science (ISAS). Launched in 2010, it served as a technology demonstration spacecraft to verify the viability of solar sail propulsion for interplanetary travel. The probe successfully deployed a 14-meter solar sail and completed a flyby of Venus.

## Key Facts
- **Launch Date:** May 20, 2010, at 21:58:22 from Yoshinobu Launch Complex Launch Pad 1.
- **Launch Vehicle:** H-IIA (specifically H-IIA-17), contracted by Mitsubishi Heavy Industries.
- **Operator:** Japan Aerospace Exploration Agency (JAXA).
- **Developer:** Institute of Space and Astronautical Science (ISAS).
- **Mass:** 308 kilograms (launch weight).
- **Dimensions:** The solar sail measures 14 meters in both length and width; the spacecraft body has a diameter of 1.6 meters and a height of 0.9 meters.
- **Propulsion:** Powered by a hybrid system utilizing a solar sail for propulsion and a spacecraft solar array for electric power.
- **Destination:** Venus (Flyby).
- **Capital Cost:** 1.3 million United States dollars (as of 2010).
- **Mission Termination:** May 15, 2025.

## FAQs
### Q: What was the primary purpose of the IKAROS mission?
A: IKAROS was designed as a technology demonstration spacecraft to test the capabilities of a solar sail. Its goal was to verify that a spacecraft could be propelled by the radiation pressure of sunlight without using traditional chemical fuel.

### Q: How did IKAROS generate power and propulsion?
A: The probe utilized a hybrid system. It used a 14-meter solar sail for spacecraft propulsion (accelerated by solar radiation) and was equipped with a spacecraft solar array to serve as its electric power source.

### Q: Did IKAROS successfully reach its target?
A: Yes, IKAROS successfully deployed its sail in June 2010 and performed a flyby of Venus on December 8, 2010, passing at a distance of 80,800 kilometers.

## Why It Matters
IKAROS represents a critical milestone in aerospace engineering as a practical demonstration of solar sail technology on an interplanetary scale. Developed by the Institute of Space and Astronautical Science (ISAS) and operated by JAXA, the probe addressed the longstanding challenge of fuel-efficient deep-space travel. By successfully utilizing radiation pressure for propulsion—a concept where photons from the sun exert force on a large sail—IKAROS proved that spacecraft can navigate the solar system without carrying heavy reserves of chemical propellant.

The mission's success provided valuable data on the deployment and durability of large membrane structures in space. Constructed from materials including polyimide, aluminium, and carbon-fiber-reinforced polymer, the sail also integrated thin-film solar cells for power generation, validating a hybrid energy model. The spacecraft's ability to maintain operations and navigate to Venus confirmed the viability of "kite-craft" mechanics, influencing the design philosophy of future deep-space probes seeking cost-effective and long-duration mission profiles. The mission formally concluded on May 15, 2025, after a mission duration of 1,826 days.

## Notable For
- **First Interplanetary Solar Sail:** Demonstrating the world's first successful use of a solar sail for interplanetary cruising.
- **Hybrid Propulsion Technology:** Integrating thin-film solar cells for electric power generation directly into the solar sail membrane.
- **Venus Flyby:** Successfully executing a flyby of Venus at a distance of 80,800 km just months after launch.
- **Rigorous Testing:** Utilizing a variety of advanced materials, including SAE 304 stainless steel and carbon-fiber-reinforced polymer, to withstand the space environment.
- **Cost Efficiency:** Achieving interplanetary demonstration with a capital cost of approximately 1.3 million USD.

## Body
### Development and Manufacturing
IKAROS was developed by the Institute of Space and Astronautical Science (ISAS) and manufactured by NEC Space Technologies. The project began with a design phase that concluded in 2007. The spacecraft was constructed to be lightweight, with a total launch mass of 308 kilograms. The structure utilizes a diverse range of materials, including aluminium, carbon-fiber-reinforced polymer, SAE 304 stainless steel, and polyimide, likely for the sail membrane and structural components.

### Specifications and Design
The spacecraft is classified as a "Small Scale Solar Powered Sail Demonstration Satellite." Its defining feature is a square solar sail measuring 14 meters in width and 14 meters in length. The main body of the probe is cylindrical, with a diameter of 1.6 meters and a height of 0.9 meters. The propulsion system is unique in that it combines the solar sail for thrust with a solar array for electrical power.

### Mission Chronology
The mission timeline is defined by several key milestones:
- **Launch:** IKAROS launched on May 20, 2010, at 21:58:22 UTC aboard an H-IIA-17 rocket from the Yoshinobu Launch Complex Launch Pad 1.
- **Deployment:** The solar sail was successfully deployed on June 20, 2010.
- **Venus Flyby:** On December 8, 2010, the probe performed a flyby of Venus, coming within 80,800 kilometers of the planet.
- **Loss of Signal:** Communication with the spacecraft was lost on May 20, 2015.
- **Mission End:** The formal mission termination date is recorded as May 15, 2025.

### Operational Context
The probe was launched alongside the Venus Climate Orbiter "Akatsuki" (though Akatsuki is not explicitly named in the source, the launch vehicle H-IIA-17 and date correspond to the shared mission profile found in the provided data regarding the launch vehicle H-IIA). The mission was operated by the Japan Aerospace Exploration Agency (JAXA), with launch services provided by Mitsubishi Heavy Industries. The total duration of the mission spanned 1,826 days.

## References

1. [Source](http://www.jspec.jaxa.jp/e/activity/ikaros.html)
2. [Source](https://www.eoportal.org/satellite-missions/ikaros)
3. [Source](https://darts.isas.jaxa.jp/en/missions/ikaros)
4. Jonathan's Space Report
5. [Source](https://spaceflightnow.com/h2a/akatsuki/100520ikaros/)
6. Freebase Data Dumps. 2013
7. Flight status of IKAROS deep space solar sail demonstrator
8. [Source](https://www.isas.jaxa.jp/home/IKAROS-blog/?itemid=783)
9. [Source](https://global.jaxa.jp/projects/sat/ikaros/topics.html#topics4743)
10. [Japan Aerospace Exploration Agency](https://www.isas.jaxa.jp/en/topics/004006.html)
11. [Source](https://global.jaxa.jp/projects/sas/ikaros/)