# MarCO-B

> one of a pair of 6U CubeSats launched on the Mars 2020 mission

**Wikidata**: [Q103851690](https://www.wikidata.org/wiki/Q103851690)  
**Source**: https://4ort.xyz/entity/marco-b

## Summary
MarCO-B (Mars Cube One-B), nicknamed WALL-E, is one of two 6U CubeSats launched in 2018 as part of NASA's Mars 2020 mission to demonstrate the feasibility of small satellites for interplanetary communication. It successfully relayed data from the InSight lander during its Mars flyby, marking a historic first for CubeSats in deep space.

## Key Facts
- **Launch Date**: May 5, 2018, at 11:05:01 UTC aboard an Atlas V 401 rocket (AV-078) from Vandenberg Space Launch Complex 3 East.
- **Operator/Manufacturer**: Jet Propulsion Laboratory (JPL).
- **Dimensions**: 24.3 cm width, 36.6 cm height, 11.8 cm length (spacecraft bus).
- **Mass**: 13.7 kg (launch weight).
- **COSPAR ID**: 2018-042C.
- **Significant Events**: Mars flyby on November 26, 2018; signal loss on December 29, 2018.
- **Orbit**: Heliocentric trajectory post-Mars flyby.

## FAQs
### Q: What was the primary purpose of MarCO-B?
A: MarCO-B served as a technology demonstrator to test CubeSat communication capabilities in deep space, relaying data from NASA's InSight lander during its descent to Mars.

### Q: Why is it nicknamed WALL-E?
A: The nickname "WALL-E" references the Pixar animated film character, chosen alongside its twin MarCO-A ("EVE") for their robotic roles in supporting the Mars mission.

### Q: Is MarCO-B still operational?
A: No. Communication with MarCO-B was lost on December 29, 2018, after it completed its primary mission objectives.

## Why It Matters
MarCO-B played a pivotal role in advancing small spacecraft technology by proving that low-cost CubeSats could operate effectively in interplanetary space. Its success demonstrated the potential for CubeSats to support critical communication roles during high-risk planetary missions, reducing reliance on larger, more expensive systems. This milestone opened doors for future missions to leverage CubeSats for tasks like real-time data relay, enhancing the efficiency and flexibility of space exploration.

## Notable For
- First CubeSats to travel to Mars and successfully transmit data from another spacecraft during atmospheric entry.
- Successfully demonstrated X-band communication in deep space.
- Operated autonomously for the majority of its 7-month journey to Mars.
- Part of the first mission to use CubeSats for interplanetary communication support.

## Body
### Launch and Mission Overview
MarCO-B launched on May 5, 2018, alongside the InSight lander and its twin MarCO-A, aboard a United Launch Alliance Atlas V 401 rocket (AV-078). The primary mission was to relay telemetry data from InSight during its landing on Mars on November 26, 2018. Both CubeSats flew by Mars at a distance of approximately 1,750 miles (2,800 km) and continued into heliocentric orbits.

### Design and Specifications
- **Structure**: 6U CubeSat (6 units of 10 cm³ each).
- **Dimensions**: 24.3 cm × 36.6 cm × 11.8 cm (spacecraft bus).
- **Mass**: 13.7 kg at launch.
- **Propulsion**: None; coasted to Mars using solar-electric power for systems.

### Communication Role
MarCO-B used an X-band transmitter to send data directly to Earth during InSight's landing, providing real-time updates. This capability reduced latency compared to traditional relay satellites like the Mars Reconnaissance Orbiter.

### Post-Mission Status
After completing its primary mission, MarCO-B continued transmitting for 12 days post-flyby. NASA declared an end to the mission on December 29, 2018, after losing contact, likely due to battery depletion or system failure. The CubeSat remains in a stable heliocentric orbit.

## References

1. [Source](https://space.skyrocket.de/doc_sdat/marco.htm)
2. Jonathan's Space Report
3. [Source](https://issfd.org/ISSFD_2019/ISSFD_2019_AIAC18_Martin-mur-Tomas.pdf)
4. [Source](https://www.jpl.nasa.gov/news/news.php?feature=7327)
5. [Source](https://earthsky.org/space/eve-wall-e-cubesats-1st-mars-image)
6. [Source](https://www.planetary.org/articles/so-long-marco)