Super Low Altitude Test Satellite (SLATS) or Tsubame was a

JAXA The is the Japanese national air and space agency. Through the merger of three previously independent organizations, JAXA was formed on 1 October 2003. JAXA is responsible for research, technology development and launch of satellites into o ...

satellite intended to demonstrate operations in very low Earth orbit (VLEO, below 200 km), using

ion engine An ion thruster, ion drive, or ion engine is a form of electric propulsion used for spacecraft propulsion. An ion thruster creates a cloud of positive ions from a neutral gas by ionizing it to extract some electrons from its atoms. The ions ...

s to counteract aerodynamic drag from the

Earth's atmosphere The atmosphere of Earth is composed of a layer of gas mixture that surrounds the Earth's planetary surface (both lands and oceans), known collectively as air, with variable quantities of suspended aerosols and particulates (which create weathe ...

which is substantial at such lower

orbital altitude A geocentric orbit, Earth-centered orbit, or Earth orbit involves any object orbiting Earth, such as the Moon or artificial satellites. In 1997, NASA estimated there were approximately 2,465 artificial satellite payloads orbiting Earth and 6,21 ...

s. It was launched on 23 December 2017, and decommissioned on 1 October 2019. The spacecraft was equipped with sensors to determine

atomic oxygen There are several known allotropes of oxygen. The most familiar is molecular oxygen (), present at significant levels in Earth's atmosphere and also known as dioxygen or triplet oxygen. Another is the highly reactive ozone (). Others are: * Atomic ...

density, an exposure facility to measure material degradation in the 200 km orbit, and a small camera. Initial designs had conventional, though slightly canted,

solar panel A solar panel is a device that converts sunlight into electricity by using photovoltaic (PV) cells. PV cells are made of materials that produce excited electrons when exposed to light. These electrons flow through a circuit and produce direct ...

s (compare to the aerodynamic shape and on-body solar panels of

GOCE The Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) was the first of European Space Agency, ESA's Living Planet Programme satellite, heavy satellites intended to map in unprecedented detail the Earth's gravity field. The spacecr ...

, which flew in a 255 km orbit). SLATS's nickname ''Tsubame'' is Japanese for

barn swallow The barn swallow (''Hirundo rustica'') is the most widespread species of swallow in the world, occurring on all continents, with vagrants reported even in Antarctica. It is a distinctive passerine bird with blue upperparts and a long, deeply f ...

. According to JAXA the name was chosen because the thin, elongated satellite in super low orbit with its set of solar array wings was reminiscent of a swallow flying low to the ground. SLATS was launched 23 December 2017 on a H-IIA rocket alongside the

GCOM-C GCOM (Global Change Observation Mission), is a JAXA project of long-term observation of Earth environmental changes. As a part of Japan's contributions to GEOSS (Global Earth Observation System of Systems), GCOM will be continued for 10 to 15 year ...

(Shikisai) satellite to a 630 km orbit, followed by orbit-lowering manoeuvres by a combination of chemical propulsion and

aerobraking Aerobraking is a spaceflight maneuver that reduces the high point of an elliptical orbit (apoapsis) by flying the vehicle through the atmosphere at the low point of the orbit (periapsis). The resulting drag slows the spacecraft. Aerobraking is ...

, with final operation at an altitude below 180 km. SLATS was operated at 7 altitudes: 271.5 and 216.8 km each for 38 days, and 250, 240, 230, 181.1 and 167.4 km each for 7 days. At 167.4 km the RCS thrusters were used in addition to the ion thruster to maintain altitude. The operation of the satellite was finished on 30 September 2019, and it was decommissioned in orbit on 1 October 2019 by terminating the communication radio and power. The satellite deorbited 1 October 2019. On 30 December 2019,

Guinness World Records ''Guinness World Records'', known from its inception in 1955 until 1999 as ''The Guinness Book of Records'' and in previous United States editions as ''The Guinness Book of World Records'', is a British reference book published annually, list ...

recognized Tsubame's achievement, which reached the lowest altitude ever among Earth observation satellites.The Japan Times, Japan's low altitude satellite Tsubame registered in Guinness World Records
30 December 2019

References

External links

JAXA SLATS page
, has images and more details
JAXA Space Technology Directorate I SLATS page
Satellites of Japan Satellites in very low Earth orbit Spacecraft launched in 2017 2017 in Japan Spacecraft launched by H-II rockets Spacecraft decommissioned in 2019 {{Japan-spacecraft-stub