News from space transport.
Launches, milestones and background from the world of space transport.
How Many Satellites Are in Medium Earth Orbit? GPS, Galileo and O3b mPOWER
An overview of the main satellite systems in medium Earth orbit (MEO), how many satellites GPS, Galileo and O3b mPOWER use and at which altitudes they fly.
Heliosynchronous Orbit: What It Means and Why Earth Observation Depends on It
What a heliosynchronous (sun-synchronous) orbit is, how it keeps a satellite at the same local time, typical altitudes and the example of NASA’s Terra satellite.
Mars Lagrange Points: What They Are and Why They Matter for Mars Communications
Where the Sun–Mars Lagrange points are, what Mars Trojan asteroids are and how Lagrange points could help avoid communication blackouts between Earth and Mars.
LEO, MEO and GEO Satellites Compared: Altitudes, Uses and Examples
What LEO, MEO and GEO mean, at which altitudes these orbits lie and what satellites in each orbit are used for, with examples from ISS, GPS, Galileo and O3b mPOWER.
Vega-C Launches FLEX and Sentinel-3C: Europe's First Dual Launch on Vega-C
ESA's FLEX Earth Explorer and the Copernicus Sentinel-3C satellite launched together on Vega-C flight VV30. FLEX will measure how plants photosynthesise from orbit.
ESA Picks ICEYE and Leonardo to Design Europe's Governmental Earth Observation Service
ESA has awarded two parallel architecture studies for the EU's future Earth Observation Governmental Service (EOGS). The results are expected in 2027, and the programme is plann…
Ariane 6 Launches MTG-I2: Europe's Third-Generation Weather Satellite System Is Complete
The second Meteosat Third Generation Imager lifted off on Ariane 6 flight VA270. Once commissioned, the three-satellite MTG system will deliver images over Europe every 2.5 minu…
LEO, SSO, MEO, GEO: The Most Important Satellite Orbits Explained
Which orbit does a satellite need? We explain low Earth orbit, sun-synchronous orbit, medium Earth orbit, geostationary orbit and the Lagrange points, with the key numbers for e…
Delta-v Explained: The Currency of Spaceflight
What delta-v is, how much it takes to reach orbit and why it is the key figure when comparing launch options and orbits.