Dive Deeper
- 🚀 What Space Missions Have Visited Mercury?
- 🔭 Mariner 10: The First to Visit Mercury
- 🛰️ MESSENGER: Mercury’s First Full-Time Orbiter
- 🌌 BepiColombo: The Ongoing European-Japanese Mission
- 📅 Why Are Mercury Missions So Rare?
- 🎯 Final Thoughts
- 📚 References
🚀 What Space Missions Have Visited Mercury?
Photo Credit: NASA
Mercury is the closest planet to the Sun, but it has not been visited very often. In fact, only three major missions have ever traveled to Mercury:
- Mariner 10 (NASA, 1973–1975)
- MESSENGER (NASA, 2004–2015)
- BepiColombo (ESA and JAXA, launched 2018, arriving 2025)
Each of these missions has helped scientists learn more about this small, mysterious planet. From its rocky surface to its giant metal core, space missions have unlocked many secrets we could never discover from Earth.
🔭 Mariner 10: The First to Visit Mercury
Mariner 10 was the first spacecraft to visit Mercury. Launched by NASA in 1973, it used a technique called a gravity assist to swing past Venus and then reach Mercury.
What It Did:
- Flew by Mercury three times in 1974 and 1975
- Took the first close-up pictures of Mercury’s surface
- Discovered that Mercury has a magnetic field
- Mapped about 45% of the planet’s surface
Before Mariner 10, scientists thought Mercury might be very similar to Earth’s Moon. After its flybys, they learned that Mercury had a giant iron core, a thin atmosphere, and some unusual landforms like scarps (huge cliffs caused by the planet shrinking).
🛰️ Fun Fact: Mariner 10 was also the first spacecraft to use gravity from one planet to reach another—a trick now used by many space missions [1].
🛰️ MESSENGER: Mercury’s First Full-Time Orbiter
MESSENGER (short for MErcury Surface, Space ENvironment, GEochemistry, and Ranging) was NASA’s second mission to Mercury and the first to go into orbit around the planet.
- Launched: 2004
- Orbited Mercury: 2011 to 2015
- Crushed into Mercury: April 30, 2015 (planned crash)
What It Discovered:
- Mapped 100% of Mercury’s surface
- Found water ice in craters near the poles
- Studied Mercury’s thin atmosphere (exosphere)
- Collected data on the planet’s internal structure and gravity
MESSENGER’s tools helped scientists understand that Mercury’s core is even larger than expected and may be partly liquid. It also found evidence of past volcanic activity and bright materials (possibly salts) on the surface.
📊 Stat: MESSENGER completed over 4,000 orbits and sent back more than 277,000 images of Mercury [2].
🌌 BepiColombo: The Ongoing European-Japanese Mission
BepiColombo is a joint mission by the European Space Agency (ESA) and Japan Aerospace Exploration Agency (JAXA). It was launched in 2018 and is expected to arrive at Mercury in December 2025.
Mission Goals:
- Study Mercury’s magnetic field
- Learn about the planet’s core and mantle
- Understand how Mercury evolved
- Examine its polar regions and strange geology
BepiColombo has already done several flybys of Earth, Venus, and Mercury to slow down and enter Mercury’s orbit. Once it arrives, it will split into two spacecraft:
- Mercury Planetary Orbiter (MPO) – managed by ESA
- Mercury Magnetospheric Orbiter (MMO) – managed by JAXA
Each orbiter will study a different part of Mercury’s environment—from its rocky surface to the way it interacts with the Sun’s solar wind.
🌠 Cool Fact: BepiColombo is named after Giuseppe “Bepi” Colombo, an Italian scientist who helped plan Mariner 10’s path [3].
📅 Why Are Mercury Missions So Rare?
Sending a spacecraft to Mercury is much harder than it sounds. Here’s why:
| Challenge | Explanation |
|---|---|
| Too close to the Sun | The Sun’s gravity pulls spacecraft faster, making it hard to slow down at Mercury. |
| High temperatures | Equipment must survive extreme heat (up to 700°F). |
| Fuel demands | It takes more fuel to slow down than to speed up. |
| Long travel time | Even though Mercury is close, missions can take 6–7 years to arrive. |
Because of these challenges, space agencies plan carefully and spend years developing the technology needed for Mercury missions.
🎯 Final Thoughts
So far, only three major space missions have visited Mercury—Mariner 10, MESSENGER, and BepiColombo. Each one has revealed amazing new facts about this tiny planet. We’ve learned about its iron core, volcanoes, magnetic field, and even water ice—all from robotic explorers.
As BepiColombo gets closer to its destination, we can expect even more discoveries. Mercury might be small and tough to reach, but it holds big secrets that help us understand how planets like Earth formed.
📚 References
- NASA – Mariner 10 Mission: https://solarsystem.nasa.gov/missions/mariner-10/overview/
- NASA – MESSENGER Mission Details: https://messenger.jhuapl.edu/
- ESA – BepiColombo Mission Overview: https://www.esa.int/Science_Exploration/Space_Science/BepiColombo
- JAXA – Mercury Magnetospheric Orbiter: https://global.jaxa.jp/projects/sat/mmo/
- Solomon, S.C., et al. “MESSENGER Mission to Mercury.” Science, 2001.