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).[1]


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.[2][3] Eventually the project was canceled in 2011 for the increased cost and the difficulty of achieving science goals.[4][5]

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.[6] It was expected to achieve ten times higher resolution and ten times higher sensitivity than its predecessor HALCA.

Science targets

Key science :

Other science targets:

See also


  1. ^ 電波天文衛星「アストロG」 [Radio astronomy satellite "Astro G"]. Yomiuri Shimbun (in Japanese). May 10, 2007. Archived from the original on May 13, 2007.
  2. ^ 事業番号3-34 (PDF) (in Japanese). Archived from the original (PDF) on November 22, 2009. Retrieved March 9, 2010.
  3. ^ 10-1.平成22年度予算案の概要 [FY 2010 Overview of budget: Strengthening of research and development capabilities] (PDF) (in Japanese). 2010. Archived (PDF) from the original on July 22, 2011. Retrieved March 9, 2010.
  4. ^ "電波天文衛星(ASTRO‐G)の状況について(報告資料)" (in Japanese). Japan Aerospace Exploration Agency. August 24, 2011. Archived from the original on February 26, 2012. Retrieved February 5, 2012.
  5. ^ 平成23年宇宙開発委員会(第35回) 配付資料 (in Japanese). Ministry of Education, Culture, Sports, Science and Technology. November 30, 2011. Retrieved February 5, 2012.
  6. ^ Saito, Hirobumi; Sakai, Shin-ichiro; Higuchi, Ken; Kishimoto, Naoko; Takeuchi, Hiroshi; Yoshihara, Keisuke; Asaki, Yoshiharu; Tsuboi, Masato; Murata, Yasuhiro; Kobayashi, Hideyuki (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. 8 (ists27): To_4_33–To_4_41. doi:10.2322/tastj.8.To_4_33.