Astro-G
Cancelled radio satellite
title: "Astro-G" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["satellites-of-japan", "cancelled-spacecraft", "radio-telescopes", "space-telescopes"] description: "Cancelled radio satellite" topic_path: "science/astronomy" source: "https://en.wikipedia.org/wiki/Astro-G" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0
::summary Cancelled radio satellite ::
::data[format=table title="Infobox spaceflight"]
| Field | Value |
|---|---|
| name | ASTRO-G |
| names_list | VSOP-2 |
| operator | JAXA |
| mission_type | Radio astronomy |
| mission_duration | Cancelled |
| orbit_reference | Geocentric (planned) |
| orbit_periapsis | 1000 km |
| orbit_apoapsis | 25000 km |
| apsis | gee |
| programme | ASTRO program |
| previous_mission | Akari (ASTRO-F) |
| next_mission | Hitomi (ASTRO-H) |
| :: |
| name = ASTRO-G | names_list = VSOP-2 | operator = JAXA | mission_type = Radio astronomy | mission_duration = Cancelled
| orbit_reference = Geocentric (planned) | orbit_periapsis = 1000 km | orbit_apoapsis = 25000 km | apsis = gee
| programme = ASTRO program | previous_mission = Akari (ASTRO-F) | next_mission = Hitomi (ASTRO-H)
ASTRO-G (also known as VSOP-2, and very rarely called VSOP-B) was a planned radio telescope satellite by JAXA. It was expected to be launched into elliptic orbit around Earth (apogee height 25,000 km, perigee height 1,000 km).
History
Astro-G was selected in February 2006 against the competition of a proposed new X-Ray astronomy mission (NeXT) and a proposed solar sail mission to Jupiter. Funding started from FY 2007 with a budget of 12 billion yen, around 100 million US dollars. It was planned to be launched in 2012 but technical difficulty with the dish antenna as well as budget constraints led to putting development on hold for fiscal year 2010. Eventually the project was canceled in 2011 for the increased cost and the difficulty of achieving science goals.
It was planned to feature a 9 m diameter dish antenna to observe in 8, 22 and 43 GHz bands, and was to be used in combination with ground radio telescopes to perform Very Long Baseline Interferometry. It was expected to achieve ten times higher resolution and ten times higher sensitivity than its predecessor HALCA.
Science targets
Key science :
- Jet structure, collimation and acceleration regions
- Structure of accretion disks around AGN
- Structure of magnetic fields in protostars
Other science targets:
- Galactic masers in star-forming region
- Extragalactic Megamasers
- Radio quiet quasars
- X-ray binaries, SNR, gravitational lenses etc.
References
References
- (May 10, 2007). link. [[Yomiuri Shimbun]]
- link
- link. (2010)
- (August 24, 2011). "電波天文衛星（ASTRO‐G）の状況について（報告資料）". [[Japan Aerospace Exploration Agency]].
- link. Ministry of Education, Culture, Sports, Science and Technology. (November 30, 2011)
- Saito, Hirobumi. (2010). "Advanced Space Technologies in Space Science Missions - Space VLBI Mission ASTRO-G Project as an Example -". Transactions of the Japan Society for Aeronautical and Space Sciences, Aerospace Technology Japan.
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