NASA has achieved another milestone.
Perseverance's robotic arm and drill were used to drill into rocks and extract samples. It took a 6 cm (2in) rock core and sealed it in a tube. This is the first robotic spacecraft to collect a sample from another planet. It will return to Earth with a separate spacecraft.
We now wait for the return of the sample.
The complexity of missions to Mars is increasing. It has been 45 years since Viking 1, Mars' first lander, reached the surface. It spent six years at Chryse Planitia, collecting soil samples and looking for signs of life. Nearly all scientists agree that the creature didn't find any signs that life existed (although some still believe that Viking 1s labeled release experiment did show signs of life). It did however characterize the Martian soils and atmosphere. It also discovered striking evidence that liquid water had flowed over the planet's surface in its ancient past.
Take a look at the progress Mars exploration has made since then.
This infographic displays the locations of all successful missions to Mars. Image credit: The Planetary Society
Complex engineering, technology, as well as mission design are the keys to success in Perseverance's mission. It was built upon the success of MSL Curiosity and previous NASA rover missions. It is more ambitious than any of its predecessors, as it collects samples from Mars and stores them on the surface in preparation for its eventual return to Earth.
Perseverance carries 43 sample tubes. The 38 tubes are for samples and five are witness tubes. These tubes were pre-launched with materials and used to collect molecular and particulate contaminants at sampling locations. According to NASA, they are designed to catalog any impurities or contaminants that may have traveled with the tube from Earth. Each tube can contain a sample either of a liquid or of a gas.
Martian rock is an ancient rock. It is not geologically active so it doesn't produce any new rocks. There is no plate-tectonics and its volcanoes remain inactive. Jezero Crater is where Perseverance works in the Isidis Planitia Impact basin. These rocks date back to the Mars Noachian Period, which spanned from approximately 4.1 billion to about 3.7 billion years ago. Because Mars was very different back then, rocks from this period are ideal targets for the search to find life.
The climate was hotter and the atmosphere was thicker. It is possible that there was even rainfall. NASA says the rovers' first sample came from South Stah in Mars Jezero Crater. It may have some of the oldest and most deep rocks in the gigantic crater. Perseverance could be sampling rocks at South Stah that contain fossilized evidence of ancient microbial activity on Mars.
This image was taken by NASA's Mars Perseverance rover using its onboard Right Navigation Camera. It is located high up on the rovers mast, and assists in driving. This image was taken Aug. 27, 2021 (Sol. 185). Credits: NASA/JPL-Caltech.
Geologists are very proud of the fact that they can bring samples from Mars back to Earth. When it comes to studying samples, Earthly laboratories have better equipment than the Perseverance Rover. While the Perseverance Rover continues its mission, we will continue to develop better and more cutting-edge technologies. Technology will be even more advanced by the time that the samples reach Earth. We don't know what we can learn from the Martian samples.
Here is Perseverance's first Mars rock sample from its tube. This was before sealing. Image Credit: NASA/JPL-Caltech
The samples will not arrive on Earth for several years. Perseverance will continue collecting samples for many years as part of the sample-return mission.
However, getting the valuable samples back to Earth isn't an easy task. It is a separate mission that will retrieve the samples and return them to Earth. This mission is very complex. This mission involves multiple spacecraft as well as multiple space agencies. It is a proposal mission at this stage.
Since I was a graduate student, I dreamed about having Mars samples to analyze.
NASA and the ESA are working together to complete the sample return mission. Although many details remain to be finalized, the agencies have reached an agreement on the overall architecture. A spacecraft consisting of a lander and a rover would be launched to Mars in July 2026. It also included an ascent rocket. The lander would then deploy the sample gathering robot to collect samples once it reached the surface in 2028. Perseverance could also retrieve samples if it is still operational at the time.
After all the samples have been collected, they will be placed in a sample return capsule inside the ascent rocket. In 2026, an additional spacecraft, called the Earth-return orbiter and designed and built by ESA, will launch from Earth. It will reach a low Martian orbit in July 2028. The ascent rocket carrying the capsule's sample return capsule will then be launched into orbit.
The rocket and Earth-return orbiter will rendezvous at low Mars orbit. A robotic arm on the return orbiter can take the sample capsule from the rocket. The samples will then be placed into an Earth return capsule, and they will be returned to Earth in the 2031 Mars/Earth transfer window.
An infographic that shows the elements of the Mars Sample Return program. Credit: ESA
All of this must work. It is not easy to get all the spacecraft launched safely and landed safely. The rendezvous between the orbiter and the ascent rocket is also a challenge. There are many other obstacles that might not be apparent.
Extreme temperatures are one of the main obstacles. To protect samples from contamination, the return capsule must be sealed and sterilized. The capsule will be sealed by the team who designed it. Brazing is a method that uses heat to bond metal pieces together. It also sterilizes everything. However, samples must be protected from excessive heat. For obvious reasons, the idea is to not expose the samples to temperatures greater than those on Mars.
One of our greatest technical challenges is being inches from metal melting at around 1,000 degrees Fahrenheit (538 degrees Celsius). We have to keep these remarkable Mars samples below the highest temperature they could have experienced on Mars. This is approximately 86 degrees Fahrenheit (30 degree Celsius), Brendan Feehan, Goddard systems engineer for ESA's orbiter. Our brazing solution has shown promising results.
Meenakshi Wadhwa is the principal scientist behind the Mars Sample Return program and is very excited about getting these ancient samples into laboratories here on Earth. Wadhwa stated that she has dreamed about having Mars samples to analyze ever since she was a graduate student. Once they have been returned, the collection of these well-documented specimens will allow us to eventually analyze them in the most prestigious laboratories on Earth.
The samples once they arrive on Earth will be analysed and re-analyzed over the next decades. This is what happened with lunar rocks that were brought back from Moon by the Apollo missions. Scientists continue to learn more about them as we develop new technology tools to study them.
This will also be true for these Martian samples. If the sample return mission succeeds.