TESS (spacecraft)

TESS (spacecraft)
Name	TESS
Mission type	Astronomy
Operator	NASA, Massachusetts Institute of Technology, Smithsonian Astrophysical Observatory
COSPAR ID	2018-049A
SATCAT	43500
Manufacturer	Orbital ATK, MIT Lincoln Laboratory
Launch date	2018-04-18
Launch rocket	Falcon 9
Launch site	Cape Canaveral Space Force Station
Disposal type	Deep space
Orbit	P/2 resonant orbit
Instruments	4 × wide-field CCD cameras

TESS (spacecraft) is a NASA-funded space telescope developed by the Massachusetts Institute of Technology and partners to perform an all-sky survey for exoplanets using the transit method. Building on heritage from Kepler (spacecraft), Hubble Space Telescope, and ground-based facilities such as Very Large Telescope and Keck Observatory, it is designed to discover small planets around bright, nearby stars suitable for follow-up by observatories including James Webb Space Telescope and Atmospheric Remote-sensing Infrared Exoplanet Large-survey. The mission is led by the NASA Goddard Space Flight Center in collaboration with multiple institutions.

Overview

TESS is a medium-class mission selected under the Explorer program administered by NASA Jet Propulsion Laboratory and built with contributions from MIT's Kavli Institute, NASA Ames Research Center, and industry partners. Its primary payload comprises four identical wide-field cameras using charge-coupled devices developed by MIT Lincoln Laboratory and electronics similar to those used on Spitzer Space Telescope and Kepler. The spacecraft operates in an unusual high-eccentricity, long-period orbit achieved using a Falcon 9 launch and a lunar gravity assist, allowing long, stable observing sectors without frequent Earth occultations.

Mission Objectives

Primary objectives include identifying transiting exoplanets around the nearest and brightest stars to enable atmospheric characterization by James Webb Space Telescope and ground-based spectrographs at Very Large Telescope, Subaru Telescope, and Magellan Observatory. Secondary goals include providing data for asteroseismology studies connected to European Space Agency projects and for time-domain astronomy coordinated with facilities like LSST and Fermi Gamma-ray Space Telescope. The mission supports community-driven science through the Mikulski Archive for Space Telescopes and partnerships with institutions such as Harvard–Smithsonian Center for Astrophysics.

Spacecraft Design and Instruments

The bus, manufactured by Orbital ATK, carries four wide-field cameras each with a 24° × 24° field of view, totaling about 24° × 96° instantaneous sky coverage. Each camera uses a lens assembly and four 2048 × 2048 CCDs produced by MIT Lincoln Laboratory, cooled by passive radiators developed with Ball Aerospace. Onboard avionics derive heritage from systems used on International Space Station resupply vehicles and incorporate high-speed solid-state recorders similar to those on Mars Reconnaissance Orbiter. The guidance system uses reaction wheels and star trackers tested on missions such as Kepler (spacecraft) and Gaia, while communications use the Deep Space Network and ground stations at Canberra Deep Space Communication Complex for science data downlink.

Launch and Orbit

TESS launched aboard a Falcon 9 from Cape Canaveral Space Force Station on 2018-04-18, placing it into an initial low Earth parking orbit before a trans-lunar injection and a lunar flyby. The lunar gravity assist placed the spacecraft into a stable, highly elliptical 13.7-day orbit in a 2:1 resonance with the Moon, similar in purpose to orbits used by missions like ARTEMIS and resonant trajectories studied for Europa Clipper. This orbit minimizes eclipse durations and provides long, uninterrupted observing sectors roughly 27 days each, enabling continuous photometric monitoring.

Science Operations and Data Processing

Science operations are managed by teams at MIT and the Smithsonian Astrophysical Observatory with scheduling coordinated through the Mission Operations Center at NASA Goddard Space Flight Center. Data are processed by the Science Processing Operations Center using pipelines descended from Kepler's algorithms, performing image calibration, cosmic-ray rejection, and transit detection with automated vetting and community follow-up coordination. Processed light curves and target pixel files are archived at the Mikulski Archive for Space Telescopes and distributed to the community, enabling coordinated campaigns with James Webb Space Telescope, Hubble Space Telescope, and ground-based observatories including Keck Observatory and European Southern Observatory.

Key Discoveries and Impact

TESS has discovered thousands of candidate exoplanets and hundreds of confirmed planets including notable systems around bright stars such as those in the Pi Mensae and LHS 3844 systems, facilitating atmospheric studies and mass measurements via radial velocity observations with HARPS, HIRES, and ESPRESSO. Discoveries include small, rocky worlds, sub-Neptunes, and multi-planet systems that have reframed occurrence-rate estimates originally informed by Kepler. TESS data have enabled asteroseismic investigations linking stellar structure to planet properties, contributed to transient detections including supernovae and variable stars studied by Pan-STARRS and Zwicky Transient Facility, and supported citizen science projects via platforms such as Zooniverse.

Mission Status and Extensions

Following its primary two-year survey, the mission was extended for additional sky coverage and longer baseline observations to improve detection sensitivity and characterize longer-period planets, with operations and funding renewed by NASA and collaborators including NOIRLab and international partners. Extended mission plans include focused observations of select sectors for multi-year monitoring, coordination with James Webb Space Telescope for follow-up, and synergy with upcoming observatories like Extremely Large Telescope, PLATO (spacecraft), and Roman Space Telescope. As of the latest phase, the spacecraft continues to operate, delivering high-quality photometry and enabling exoplanet science across the astronomical community.

Category:NASA satellites Category:Exoplanet search projects Category:Space telescopes