Mars Sample Return
The Mars Sample Return campaign kicked off with the launch of the Mars 2020 Perseverance Rover on 30 July 2020. This multi-stage campaign is a joint effort between NASA and the European Space Agency (ESA) to return martian samples to Earth by the mid 2030s.
The campaign will take place in three stages:
Stage 1: Collection of Martian Samples
Perseverance landed on Mars on 18 February 2021. It is currently collecting samples of martian rock and soil to bring back to Earth for analysis. The rover is also tasked with searching for signs of ancient life to understand the past habitability of Mars.
Stage 2: Return to Earth of Martian Samples
Bringing the samples back to Earth involves a multi-spacecraft approach. NASA’s Sample Retrieval Lander will collect the martian samples from Perseverance. Once collected, the Mars Ascent Vehicle will launch the samples off Mars and into orbit where ESA’S Earth Return Orbiter will catch, store, and return them to Earth.
Stage 3: Analysis of Martian Samples
When the samples get to Earth, scientists around the world will have opportunities to work with the samples in state-of-the-art laboratories. The return of carefully selected samples from Mars has been a long-term goal of the planetary community. The diverse set of martian samples collected by Perseverance could help scientists understand if ancient life ever existed on Mars.
Other Mars Sample Return Missions
Tianwen-3
China is planning its own mission to return samples from Mars to Earth in the early 2030s. The Tianwen-3 mission will be launched in two parts:
- A lander and ascent vehicle that will touch down, collect samples and send them into Mars orbit
- An orbiter and sample return module that will capture the samples in orbit and bring them back to Earth.
Martian Moons eXploration (MMX)
The Japanese Space Agency (JAXA) is sending the Martian Moons eXploration (MMX) mission to explore the two moons of Mars, Phobos and Deimos. MMX consists of an orbiter, lander and sample return module, and aims to return the first samples from Phobos to Earth in the early 2030s. The mission is a collaboration with NASA, ESA, the German Space Agency (DLR) and the French Space Agency (CNES), with international partners providing instrumentation, testing facilities and ground support.
The mission aims to help scientists resolve questions about the origin of the moons. The two main theories are that Phobos and Deimos are either captured asteroids or debris from a large impact with Mars. Samples from Phobos and Deimos returned by MMX will also hold clues to the composition of the martian surface, since the moons will have accumulated material ejected from impacts with Mars over billions of years.
Perseverance
Perseverance is currently the largest and heaviest rover ever sent to Mars. The design is based on the Mars Science Laboratory’s rover Curiosity. At around 2 meters high and 3 meters wide, Perseverance is about the size of a small car.
![](https://www.europlanet-society.org/wp-content/uploads/2021/06/1-PIA23764-RoverNamePlateonMars-1024x576.png)
Perseverance has four main science objectives:
1. Looking for Habitability
Perseverance will study the geology of the landing site and surrounding area to identify past martian environments that may have been life-friendly.
2. Seeking Biosignatures
Perseverance will look for signs of past microbial life in environments that may once have been habitable, particularly in rocks containing minerals with properties that help preserve signs of life.
3. Caching Samples
Perseverance will collect scientifically valuable rock and soil samples and deposit them carefully on the martian surface and in the rover’s belly so that they can be brought back to Earth by future missions.
4. Preparing for Humans
Perseverance will test technologies that use natural resources on Mars that could be used in future human exploration of the Red Planet.
Deep Dive: Science Goals and Instruments of Perseverance
Science Goals
The strategy for exploring Mars has developed over the last 50 years. Each successful mission has contributed to our overall understanding of Mars and, with each new bit of knowledge, the focus of exploration has shifted.
Most of the past missions to Mars have focused on the strategies of ‘following the water’ and ‘exploring martian habitability’. The surface of Mars is currently cold, dry and bathed in damaging cosmic and solar radiation, so it is unlikely that live organisms will be found at Perseverance’s landing site, Jezero Crater. However, Jezero once held a deep lake and river delta, so is a promising site to look for Perseverance to achieve its strategic aim of ‘seeking signs of past life’.
Perseverance will also collect samples of martian rock and regolith that will be brought to Earth for analysis in terrestrial laboratories.
Instruments
![Annotated image of NASA Perseverance Rover](https://www.europlanet-society.org/wp-content/uploads/2021/02/25045_Perseverance_Mars_Rover_Instrument_Labels-web-1024x578.jpg)
Perseverance is equipped with seven scientific instruments that allow the rover to investigate the geology, atmosphere and environmental conditions of Mars, as well as to detect any biosignatures that may indicate life was once present at Jezero.
Cameras
There are two main camera systems on Perseverance: Mastcam-Z and SuperCam.
The dual Mastcam-Z cameras are the ‘eyes’ of Perseverance. This mast-mounted system can take high-definition colour panoramic images and videos of the martian surface. The cameras can look 360-degrees around the rover and create 3D images and videos. Mastcam-Z can also zoom into the fine details of distant objects, making it easier for scientists to find interesting rocks to target. As well as helping to guide the rover over the martian terrain, Mastcam-Z helps scientists to determine the mineralogy of the surface of Mars.
SuperCam is located on the ‘head’ of Perseverance. Its combination of a camera and laser allows scientists to look at features in rocks and determine their chemical composition. With a range of over 7 metres, SuperCam can analyse rocks that may be out of reach of Perseverance’s robotic arm.
In total, the rover has 23 cameras for engineering, science, and entry, descent and landing purposes.
Weather Station
The Mars Environmental Dynamics Analyser (MEDA) is Perseverance’s onboard weather station. MEDA’s sensors measure the temperature, pressure, humidity, radiation, and wind speed and direction on Mars. MEDA also monitors martian dust by measuring the size and shape of dust grains. The daily weather and radiation reports provided by MEDA will help prepare for future human missions to Mars.
Spectrometers
At the end of its robotic arm, Perseverance carries two spectrometers, which are tools for determining the chemical elements that make up rocks.
The Planetary Instrument for X-ray Lithochemistry (PIXL) spectrometer uses X-rays for fine-scale analysis of chemical elements. PIXL also contains a camera that can see objects as small as a grain of salt. The pairing of a spectrometer and camera allows scientists to look for textures and chemical signatures left by past microbial life.
The Scanning Habitable Environments with Raman and Luminescence for organics and chemicals (SHERLOC) is the first spectrometer of its kind to be sent to Mars. SHERLOC uses a ultraviolet laser to analyse minerals and detect organic compounds that have been altered by water and may preserve biosignatures of past life. Just like the fictional character, Sherlock Holmes, SHERLOC has a side-kick called WATSON, a camera that takes close-up colour images of rock and dust grains, and also supports Perseverance’s other instruments.
Radar
The Radar Imager for Mars’ Subsurface Experiment (RIMFAX) is located at the rear of the rover. RIMFAX uses radar waves to penetrate the martian surface to see geological features in the subsurface. The radar can reach depths of more than 10 meters and can detect ice, water, and brines (salty water). This will help scientists understand what is below the martian surface and investigate rocks and (potentially) fluids that have been buried over time.
Technology Demonstration
To help prepare for future human missions to Mars, scientists need to know if there are natural resources in the martian environment that could be used for life support and fuel. The martian atmosphere contains only about 0.13% oxygen, so human missions will need to find a reliable supply of oxygen for breathing.
The Mars Oxygen In-Situ Resource Utilisation Experiment (MOXIE) is a technology demonstrator carried by Perseverance. It is designed to produce oxygen by splitting carbon dioxide molecules from the martian atmosphere into its constituent parts. Over 16 operational cycles, MOXIE successfully generated 122 grams of oxygen. These results could pave the way for a scaled-up life-support system for future astronauts and the production of oxygen for use as rocket fuel.
Ingenuity Helicopter
NASA’s Mars helicopter, Ingenuity, made history on 19 April 2021 by completing the first powered and controlled flight on another planet.
![](https://www.europlanet-society.org/wp-content/uploads/2021/06/heli-movement-far-1024x576.gif)
During its first flight, Ingenuity ascended 3 meters from the martian surface, hovered in the thin atmosphere and completed a turn, before touching back down. By the end of its mission in January 2024, Ingenuity had completed 72 flights spanning over two hours of flying, travelling 17 kilometres in distance, and reaching heights of 24 metres above the martian surface.
Ingenuity’s main job was to demonstrate a potential new way to explore Mars from the air. Its success has helped to understand how future rovers could work with aerial crafts to benefit missions.
Since the martian atmosphere is significantly less dense than Earth’s atmosphere, Ingenuity was designed with a mass of just 1.8 kilogrammes. The helicopter’s two 1.2-metre-long carbon fibre blades could spin at up to 2,400 revolutions per minute (around six times faster than helicopter blades spin on Earth) giving Ingenuity the power to lift off the martian surface.
Ingenuity was also designed to fly autonomously. The flight-plans were sent in advance, as the 11-minute communication delays between Earth and Mars meant that the helicopter could not be controlled ‘live’.
Future aerial crafts could investigate martian terrain that rovers may not be able to reach, carry science instruments, and could even help future astronauts explore Mars. They may also play a role in bringing the samples collected by Perseverance back to Earth.
Returning the Samples
The processes of returning the samples collected by the Mars 2020 rover Perseverance safely back to Earth relies on a complex mission structure involving numerous spacecraft.
Sample Retrieval Lander
A Sample Retrieval Lander is planned to land in or close to Jezero Crater to fetch the martian samples collected by Perseverance. In the current architecture, this lander would carry NASA’s Mars Ascent Vehicle, the sample return container, two Sample Recovery Helicopters, and ESA’s Sample Transfer Arm. It would be the biggest lander ever sent to Mars.
Perseverance would drive to the Sample Retrieval Lander and the Sample Transfer Arm would transfer the sample tubes from the Perseverance’s belly into the Orbiting Sample container.
Sample Recovery Helicopters
In the event that Perseverance would be unable to deliver the primary samples to the Sample Retrieval Lander, two Sample Recovery Helicopters would fly and land close to the sample tube cache. The rotorcraft would drive on wheels to retrieve one sample tube at a time, then fly back to the Sample Retrieval Lander. The Sample Transfer Arm would stow the tubes in the Orbiting Sample container. The helicopters would repeat the process for all sample tubes selected for recovery.
Mars Ascent Vehicle
The Mars Ascent Vehicle, built by NASA, would transport the martian samples inside the Orbiting Sample container into orbit. The Mars Ascent Vehicle would be thrown into the air by the lander, after which its rocket would ignite for the first launch from another planet. Once in orbit, the basket-ball-sized Orbiting Sample would be released, intercepted and captured by ESA’s Earth Return Orbiter.
Earth Return Orbiter
ESA’s Earth Return Orbiter would capture the Orbiting Sampleusing NASA’s Capture, Containment, and Return System(CCRS). Once safely inside the Earth Return Orbiter, the Orbiting Sample would be closed, sterilised and sealed inside the Earth Entry System to create a secure containment barrier.
To ensure further protection of the terrestrial environment, around a week before the Earth Return Orbiter arrives back at Earth, a full system safety check will be performed to ensure the containment barriers have not been breached, as well as avoiding contamination to the terrestrial environment when the Earth Entry System lands on the Earth’s surface.
Earth Entry System
Three years after reaching Mars, Earth Return Orbiter would spend two years changing its orbit to make its way back to Earth. Once the orbiter is around three days away from the Earth it would release the Earth Entry System to Earth where it would land and be transported to a specialised Sample Receiving Facility.
References
https://sci.esa.int/web/mars-express/-/55481-the-ages-of-mars
In Depth | Mars – NASA Solar System Exploration
Carr, M. H. and Head, J. W. 2010. Geologic History of Mars. Earth and Planetary Science Letters, 294, pp.185-203.