|Names||Nano-Japan Astrometry Satellite Mission for Infrared Exploration|
|Mission type||Astrometric observatory|
|Mission duration||Planned: 2 years|
|Manufacturer||NAOJ / ISSL|
|Launch mass||35 kg (77 lb)|
|Dimensions||50.8 × 50.8 × 51.2 cm (20.0 × 20.0 × 20.2 in)|
|Perigee altitude||800 km (500 mi)|
|Apogee altitude||800 km (500 mi)|
|Diameter||5.25 cm (2.07 in)|
|Focal length||167 cm (66 in)|
The Nano-Japan Astrometry Satellite Mission for Infrared Exploration (Nano-JASMINE) is an astrometric microsatellite developed by the National Astronomical Observatory of Japan, with contributions by the University of Tokyo's Intelligent Space Systems Laboratory. As of 2015[update], the satellite was planned for launch together with CHEOPS (Characterising Exoplanets Satellite) in 2019. However, this launch took place (in December 2019) without Nano-JASMINE as one of the three piggyback payloads. Some sources name 2021 as the launch year of the satellite.
Nano-JASMINE is a microsatellite measuring 50.8 by 50.8 by 51.2 centimetres (20.0 by 20.0 by 20.2 in) and weighing approximately 35 kilograms (77 lb). It carries a small, 5.25-centimetre (2.07 in) Ritchey–Chrétien telescope that will make observations in the infrared spectrum, allowing for easier observation toward the centre of the Milky Way. Its exterior is covered with GaAs solar cells providing approximately 20 watts of power. Due to limited bandwidth, Nano-JASMINE will employ a Star Image Extractor (SIE) for onboard raw image processing that will extract and transmit only specific object data.
Nano-JASMINE is Japan's first and the world's third astrometric survey spacecraft, following Hipparcos (1989) and Gaia (2013), both launched by the European Space Agency (ESA). It is the pathfinder in a planned series of three spacecraft of increasing size and capability; the second is JASMINE (originally and officially still called "Small-JASMINE") with a 30-centimetre (12 in) telescope, and the third with an 80-centimetre (31 in) telescope.
The spacecraft is designed to have an astrometric accuracy (2–3 mas for stars brighter than 7.5 magnitude) comparable to Hipparcos (1 mas). Nano-JASMINE should be able to detect approximately four times the number of stars as Hipparcos. Given the time difference between these missions, combining the data sets of Nano-JASMINE and Hipparcos will constrain the positions of stars whose current positions are poorly known owing to uncertainty in their motion since being measured by Hipparcos, and should provide an order-of-magnitude increase in the accuracy of proper motion measurements (approximately 0.1 mas/year; 0.2 mas/year for stars brighter than 9 magnitude).
Nano-JASMINE had been scheduled for launch aboard a Tsyklon-4 rocket from the Brazilian Space Agency's Alcântara Launch Center (CLA). The launch was originally contracted for August 2011, but was delayed to the November 2013 to March 2014 time frame. Various issues have held back its launch, first due to delays in both the construction of the launch site and development of the launch vehicle, and later due to Brazil backing out of the Tsyklon-4 partnership with Ukraine leading to the rocket's indefinite hold. In March 2015, talks to arrange a flight for Nano-JASMINE began between NAOJ and ESA. It was to be launched as a piggyback payload with CHEOPS on a Soyuz rocket in 2019. As of late 2020, the launch of Nano-JASMINE is foreseen in 2021.