The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radio navigation system owned by the United States government and operated by the United States Space Force. It is one of the global navigation satellite systems (GNSS) that provide geolocation and time information to a GPS receiver anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites. It does not require the user to transmit any data, and operates independently of any telephonic or Internet reception, though these technologies can enhance the usefulness of the GPS positioning information. It provides critical positioning capabilities to military, civil, and commercial users around the world. Although the United States government created, controls and maintains the GPS system, it is freely accessible to anyone with a GPS receiver.
Galileo is a global navigation satellite system (GNSS) that went live in 2016, created by the European Union through the European Space Agency (ESA), operated by the European Union Agency for the Space Programme (EUSPA), headquartered in Prague, Czechia, with two ground operations centres in Fucino, Italy, and Oberpfaffenhofen, Germany. The €10 billion project is named after the Italian astronomer Galileo Galilei.
GLONASS is a Russian satellite navigation system operating as part of a radionavigation-satellite service. It provides an alternative to Global Positioning System (GPS) and is the second navigational system in operation with global coverage and of comparable precision.
The Ka band is a portion of the microwave part of the electromagnetic spectrum defined as frequencies in the range 26.5–40 gigahertz (GHz), i.e. wavelengths from slightly over one centimeter down to 7.5 millimeters. The band is called Ka, short for "K-above" because it is the upper part of the original NATO K band, which was split into three bands because of the presence of the atmospheric water vapor resonance peak at 22.24 GHz (1.35 cm), which made the center unusable for long range transmission. The 30/20 GHz band is used in communications satellite uplinks in either the 27.5 GHz or 31 GHz bands, and in high-resolution, close-range targeting radars aboard military airplanes. Some frequencies in this radio band are used for vehicle speed detection by law enforcement. The Kepler Mission used this frequency range to downlink the scientific data collected by the space telescope.
A satellite navigation or satnav system is a system that uses satellites to provide autonomous geopositioning. A satellite navigation system with global coverage is termed global navigation satellite system (GNSS). As of 2023, four global systems are operational: the United States's Global Positioning System (GPS), Russia's Global Navigation Satellite System (GLONASS), China's BeiDou Navigation Satellite System, and the European Space Agency's Galileo.
The International Cospas-Sarsat Programme is a satellite-aided search and rescue (SAR) initiative. It is organized as a treaty-based, nonprofit, intergovernmental, humanitarian cooperative of 45 nations and agencies. It is dedicated to detecting and locating emergency locator radio beacons activated by persons, aircraft or vessels in distress, and forwarding this alert information to authorities that can take action for rescue. Member countries support the distribution of distress alerts using a constellation of around 65 satellites orbiting the Earth which carry transponders and signal processors capable of locating an emergency beacon anywhere on Earth transmitting on the Cospas-Sarsat frequency of 406 MHz.
The Space Test Program (STP) is the primary provider of spaceflight for the United States Department of Defense (DoD) space science and technology community. STP is managed by a group within the Advanced Systems and Development Directorate, a directorate of the Space and Missile Systems Center of the United States Space Force. STP provides spaceflight via the International Space Station (ISS), piggybacks, secondary payloads and dedicated launch services.
Radio occultation (RO) is a remote sensing technique used for measuring the physical properties of a planetary atmosphere or ring system. Other satellite carriers onboard GNSS-Radio occultation include CHAMP (satellite), GRACE and GRACE-FO, MetOp and the recently launched COSMIC-2.
Planet Labs PBC is a publicly held American Earth imaging company based in San Francisco, California. Their goal is to image the entirety of the Earth daily to monitor changes and pinpoint trends.
COSMIC-2 also known as FORMOSAT-7, is the constellation of satellites for meteorology, ionosphere, climatology, and space weather research. FORMOSAT-7 is a joint US-Taiwanese project including National Space Organization (NSPO) on the Taiwanese side and the National Oceanic and Atmospheric Administration (NOAA) and the United States Air Force (USAF) on the US side. FORMOSAT-7 is the successor of FORMOSAT-3 The six satellites of the constellation were launched 25 June 2019 on a Falcon Heavy rocket. They reached their designated mission orbits in February 2021, after eighteen months of gradual orbital adjustments. Full operational capability was achieved in October 2021.
Spire Global, Inc. is a space-to-cloud data and analytics company that specializes in the tracking of global data sets powered by a large constellation of nanosatellites, such as the tracking of maritime, aviation and weather patterns.
Starlink is a satellite internet constellation operated by private aerospace company SpaceX, providing coverage to over 71 countries. It also aims for global mobile phone service after 2023.
ÑuSat satellite series, is a series of Argentinean commercial Earth observation satellites. They form the Aleph-1 constellation, which is designed, built and operated by Satellogic.
ELA-4, is a launch pad and associated facilities at the Centre Spatial Guyanais in French Guiana located along the Route de l'Espace in the Roche Christine site, between ELA-3 and ELS launch facilities. The complex is composed of a launch pad with mobile gantry, an horizontal assembly building and a dedicated launch operations building. ELA-4 is operated by Arianespace as part of the Ariane 6 program. As of November 2022 the first launch is scheduled for the fourth quarter of 2023.
Paz is a Spanish Earth observation and reconnaissance satellite launched on 22 February 2018. It is Spain's first spy satellite. The satellite is operated by Hisdesat. Paz was previously referred to as SEOSAR.
The European Union Agency for the Space Programme (EUSPA) is a space agency, managing the European Union Space Programme as one of the agencies of the European Union (EU). It was initially created as the European Global Navigation Satellite Systems Supervisory Authority (GSA) in 2004, reorganised into the European Global Navigation Satellite Systems Agency in 2010, and established in its current form on May 12, 2021. EUSPA is a separate entity from the European Space Agency (ESA), although the two entities work together closely.
This article documents expected notable spaceflight events during the year 2025.
The Sentinel-6 Michael Freilich (S6MF) is a radar altimeter satellite developed in partnership between several European and American organizations. It is part of the Jason satellite series and is named after Michael Freilich. S6MF includes synthetic-aperture radar altimetry techniques to improve ocean topography measurements, in addition to rivers and lakes. The spacecraft entered service in mid 2021 and is expected to operate for 5.5 years.
