# Deimos and Phobos Interior Explorer

> ESA spaceflight mission concept to study the moons of Mars

**Wikidata**: [Q60756012](https://www.wikidata.org/wiki/Q60756012)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Deimos_and_Phobos_Interior_Explorer)  
**Source**: https://4ort.xyz/entity/deimos-and-phobos-interior-explorer

## Summary
Deimos and Phobos Interior Explorer (DePhine) is an abandoned European Space Agency concept for a space probe that would have orbited Mars to study its two small moons. Proposed in 2016, the mission was designed to investigate the interior structure and origin of Deimos and Phobos.

## Key Facts
- Inception year: 2016
- Sponsoring agency: European Space Agency (ESA)
- Mission type: Space probe and orbiter targeting Mars
- Target destinations: Deimos and Phobos, the two natural satellites of Mars
- Status: Abandoned project
- Alternate name: DePhine
- Only documented in English-language sources (1 Wikipedia sitelink)

## FAQs
### Q: What was the main goal of the Deimos and Phobos Interior Explorer?
A: The mission concept aimed to study the interior structure and composition of Mars' two moons to better understand their formation and evolution.

### Q: Why was it called "DePhine"?
A: DePhine is a contraction of "Deimos and Phobos Interior Explorer," making it easier to reference in technical documents and discussions.

### Q: Is DePhine still an active mission?
A: No, DePhine remains a concept study that was never approved for development or launch, classifying it as an abandoned project.

### Q: What kind of spacecraft was DePhine supposed to be?
A: It was designed as both a space probe (non-Earth orbiting robotic spacecraft) and an orbiter that would circle Mars to study its moons.

## Why It Matters
While DePhine never progressed beyond the concept phase, it represents ESA's scientific interest in understanding Mars' enigmatic moons. Deimos and Phobos are among the smallest natural satellites in the solar system, and their origins remain debated—are they captured asteroids or remnants of a giant impact? A dedicated mission like DePhine would have provided crucial data about their internal structure, surface composition, and potential resources. Such investigations are vital for future Mars exploration, as the moons could serve as stepping stones for human missions or as sources of scientific discovery about the early solar system. The concept also demonstrates ESA's long-term strategic thinking about Mars exploration beyond just the planet itself.

## Notable For
- One of the few proposed missions specifically dedicated to studying both Martian moons
- Represents ESA's consideration of missions beyond Mars surface exploration
- Concept emerged during a period of renewed international interest in Mars' moons (mid-2010s)
- Demonstrates the agency's scientific interest in small body exploration within the Mars system

## Body
### Mission Concept and Objectives
The Deimos and Phobos Interior Explorer emerged from ESA's studies of potential missions to expand Mars system science. As an orbiter concept, the spacecraft would have remained in Mars orbit while conducting detailed investigations of both moons, rather than landing on either body.

### Scientific Context
Deimos and Phobos are among the most mysterious objects in the solar system. Their small size—Phobos is 22.2 km across at its widest, Deimos just 12.6 km—makes them difficult targets for observation from Earth or Mars orbit. A dedicated mission would have provided unprecedented detail about their composition and structure.

### Project Status
The mission concept was proposed in 2016 but never advanced to the development phase. It remains classified as an abandoned project within ESA's mission portfolio, with no current plans for revival or implementation.