January 19 

19 January 2006

Artist's concept of New Horizons. Credit: JHUAPL/SwRI

New Horizons, the first spacecraft to explore the dwarf planet Pluto, was launched from Cape Canaveral at 19:00 UT on January 19, 2006, on an Atlas V 551 booster with a Star 48B third stage directly into an interplanetary trajectory. New Horizons flew by Jupiter in February 2007, Pluto on July 14, 2015, and the Kuiper belt object (486958) Arrokoth on January 1, 2019. It is the fifth space probe to achieve the escape velocity needed to leave the Solar System. 

   The primary objectives of the mission are to characterize the global geology and morphology and map the surface composition of Pluto and Charon and characterize the neutral atmosphere of Pluto and its escape rate. Other objectives include studying the time variability of Pluto's surface and atmosphere, imaging Pluto and Charon in stereo, mapping the terminators and composition of selected areas of Pluto and Charon at high-resolution, characterizing Pluto's upper atmosphere, ionosphere, energetic particle environment, and solar wind interaction, searching for an atmosphere around Charon and characterizing its energetic particle environment, refining bulk parameters, orbits, and bolometric Bond albedos of Pluto and Charon, searching for additional satellites and rings, and characterizing one or more Kuiper Belt Objects. 

New Horizons in the clean room at KSC’s Payload Hazardous Servicing Facility. Credit: NASA

   The spacecraft has the shape of a thick triangle (0.68 x 2.11 x 2.74 m) with a cylindrical radiothermal generator (RTG) protruding from one vertex in the plane of the triangle and a 2.1 m high-gain radio dish antenna affixed to one flank side. An aluminum central cylinder supports surrounding honeycomb panels. The central cylinder acts as the payload adapter fitting and houses the propellant tank. The 465 kg launch mass included 80 kg of propellant. The entire structure is covered in thermal multi-layer insulating blankets and thermal control is further achieved by electrical dissipation and RTG waste heat, thermal louvers, and external shunt plates. Communication from Pluto was via X-band at a rate of 600 bps through the high gain antenna to a 70-m DSN dish. There are also two low gain antennas for communications within 5 au and a medium gain antenna with uplink capability to 50 au. The RTG provided approximately 228 W at encounter in 2015. Hydrazine monopropellant is used for propulsion via four 4.4 N thrusters and twelve 0.8 N thrusters, a delta-V capability of 290 m/s was available after launch. The hydrazine is stored in a titanium tank separated from the gaseous nitrogen pressurant by a girth-mounted diaphragm. The spacecraft has both 3-axis stabilized and spin-stabilized modes. Star cameras are mounted on the side of the spacecraft for navigation.

Launch of New Horizons: NASA

   The 31 kg science payload package requires 21 W of power and consists of seven scientific instruments. The Long Range Reconnaisance Imager (LORRI) consists of a visible light, high-resolution CCD Imager. The Ralph instrument is composed of two parts, a visible CCD imager (MVIC) and a near-infrared imaging spectrometer (LEISA). The Alice instrument is an ultraviolet imaging spectrometer. The plasma and high energy particle spectrometer suite (PAM) consists of SWAP, a toroidal electrostatic analyzer and retarding potential analyzer, and PEPSSI, a time-of-flight ion and electron sensor. The Radio Science Experiment (REX) will use an ultrastable oscillator to conduct radio science investigations. A student-built dust counter (SDC) will make dust measurements in the outer solar system.

Pluto's image taken by New Horizons on July 14, 2015, from a range of 35,445 kilometers. Credit: Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute/Alex Parker

© 2026, Andrew Mirecki

19 January 2024

SLIM lander on the lunar surface captured by the LEV-2 (SORA-Q) rover. Credit: JAXA / TOMY / Sony Group Corporation / Doshisha University

Japanese Smart Lander for Investigating Moon (SLIM) spacecraft landed near Shioli crater on the Moon on January 19, 2024. Despite an engine failure that caused it to land on its side at a 90-degree angle, the spacecraft survived three lunar nights, operating until its last contact on April 28, 2024.

   SLIM launched on September 6, 2023, at 23:42:11 UT as a ride-share payload with the XRISM mission on an H2A booster from the Tanegashima Space Center in Japan. All systems were reported nominal after upper stage separation putting it on a four month journey to lunar orbit. It made a close approach, 5000 km altitude, of the Moon on October 4 at 6:47 UT and continued on an elliptical orbit that brought it back to the Moon on December 25, 2023. A thruster firing put it into a 600 x 4000 km altitude lunar polar orbit with a period of approximately 6.4 hours at 07:51 UT.

Artist's impression of the SLIM lander in lunar orbit. Credit: JAXA

   Over the course of about a month it trimmed its orbit into a circular, 600 x 600 km orbit, and then lowered its perilune to 15 km. A powered descent phase brought it down to 3.5 km altitude, at 15:00 UT on January 19, 2024. Using the onboard camera, the spacecraft position with respect to the surface was determined. It then entered the vertical descent phase, descending towards the surface. At the end of this phase, it began a program of obstacle detection, to avoid any hazards at the landing site. The propulsion system failure occurred at an altitude of approximately 50 m when the nozzle broke off and thrust was reduced in one of the two main engines. At about 3 meters altitude the engines cut off and the lander dropped to the surface, at approximately 15:20 UT at 25.2510 E, 13.3160 S. The landed mass was about 210 kg, landing objective was to be within 100 meters of the target point, the ejecta blanket of Shioli crater.

Image of the lunar surface taken by the SLIM lander at an altitude of around 50 meters. The nozzle section, detached and falling from the SLIM main engine, has been confirmed. Credit: JAXA

   Following landing, signals were sent from and received by SLIM, but the solar cells were not charging the batteries. Although SLIM landed successfully after one of the thrusters failed at about 50 meters altitude, its solar panels ended up facing westward. (The Sun was in the east at the time of landing.) Only limited battery power was available for a few hours. SLIM was powered down at 17:57 UT when the batteries reached 12%. The LEV-1 and LEV-2 rovers successfully deployed. On January 28, sunshine reached a point where it struck the solar panels, providing power, and SLIM resumed operations and communications until lunar night. 

   Telemetry was received after the first lunar night ended and the Sun reached the solar panels, on February 25, although the Sun set on March 1 and the spacecraft was put back to sleep. The spacecraft was again operable after its second lunar night when Sun hit the solar panels on March 26, and SLIM was able to take images and send telemetry. After surviving its third lunar night, SLIM operated until its last contact on April 28, 2024. The mission was declared over on August 23 after numerous unsuccessful attempts to contact the lander. 

Left: image of the lunar surface captured by the navigation camera onboard SLIM after landing. Right: A lunar surface scan mosaic image captured by the multi-band camera onboard SLIM. The grey area on the right of the mosaic lacks data due to the discontinuation of scanning operation. Credit: JAXA / Ritsumeikan University / University of Aizu.

© 2026, Andrew Mirecki