After seven months and about 300 million miles, the Mars 2020 Perseverance rover landed on the Red Planet on February 18 for a primary mission span of at least one Martian year (687 Earth days).
NASA chose Jezero Crater as the landing site for Perseverance. Scientists believe the area was once flooded with water and was home to an ancient river delta. Conceivably, microbial life could have lived in Jezero during one or more of these wet times. If so, signs of their remains might be found in lakebed or shoreline sediments. Scientists will study how the region formed and evolved, seek signs of past life, and collect samples of Mars rock and soil that might preserve these signs.
And while Perseverance was designed to find evidence of ancient life, it will also be implementing technologies that could enable future life — human life — to exist on Mars.
First Leg of a Round Trip
Perseverance is the first leg of a round trip to Mars. The verification of ancient life on Mars carries an enormous burden of proof. Perseverance is the first rover to bring a sample caching system to Mars in order to package promising samples for return to Earth by a future mission.
Rather than pulverizing rock the way the drill on the Curiosity rover does, Perseverance's drill will cut intact rock cores that are about the size of a piece of chalk and will place them in sample tubes. The tubes carried in the belly of Perseverance are about the size and shape of a standard lab test tube. Made chiefly of titanium, each sample tube weighs less than 2 ounces. A white exterior coating guards against heating by the Sun potentially changing the chemical composition of the samples after Perseverance deposits the tubes on the surface of Mars. Laser-etched serial numbers on the exterior will help the team identify the tubes and their contents.
As Perseverance investigates Mars, mission scientists will determine when and where it will drill for samples. This cargo will be packaged in the tubes with the most intricate and technologically advanced mechanism ever sent into space: the Sample Caching System. Of the tubes aboard Perseverance, up to 38 are destined to be filled with Martian rock and regolith. The other five are “witness tubes” that have been loaded with materials geared to capture molecular and particulate contaminants. They will be opened one at a time on Mars to witness the ambient environment primarily near sample collection sites, cataloging any Earthly impurities or contaminants from the spacecraft that may be present during sample collection.
NASA and the European Space Agency (ESA) are studying a retrieval mission that would include a NASA-led Sample Retrieval Lander that would launch the retrieved samples into Mars orbit and an ESA-led Earth Return Orbiter that would rendezvous with the samples in Mars orbit and bring them back to Earth.
As currently envisioned, the lander launches in 2026 and arrives at Mars in 2028, touching down close to Perseverance near Jezero Crater. It deposits the fetch rover on Mars to pick up the stashed samples and transfer them to the rocket. Another option is for Perseverance to retain some of its samples and deliver them directly to the rocket. The rocket would then become the first ever to launch off another planet, transporting the sample return container into orbit around Mars, where the orbiter will capture the sealed sample container and return to Earth in the early 2030s.
The Ingenuity Mars Helicopter is ready for its debut. The 4-pound helicopter — a combination of specially designed components and off-the-shelf parts — is stowed on Perseverance's belly and receives its charge from the rover's power supply. Once Ingenuity is deployed on Mars’ surface, its batteries will be charged solely by the helicopter's own solar panel.
The small craft will have a 30-Martian-day (31-Earth-day) experimental flight-test window beginning this spring. For the very first flight, the helicopter will take off a few feet from the ground, hover in the air for about 20 to 30 seconds, and land. The helicopter flies on its own without human control. It must take off, fly, and land with minimal commands from Earth sent in advance.
After that, the team will attempt additional experimental flights of incrementally farther distance and greater altitude. After the helicopter completes its technology demonstration, Perseverance will continue its scientific mission.
If it succeeds, Ingenuity will prove that powered, controlled flight by an aircraft can be achieved at Mars, enabling future Mars missions to potentially add an aerial dimension to their explorations with second-generation rotorcraft.
A Device with “MOXIE”
One of the hardest things about sending astronauts to Mars will be getting them home. Launching a rocket off the surface of the Red Planet will require industrial quantities of oxygen, which, along with rocket fuel, makes up propellant. A crew of four would need about 55,000 pounds (25 metric tons) of it to produce thrust from 15,000 pounds (7 metric tons) of rocket fuel. But instead of shipping all that oxygen, what if the crew could make it out of thin (Martian) air?
The Mars Oxygen In-situ Resource Utilization Experiment (MOXIE) instrument stands apart from Perseverance's primary science. One of the rover's main purposes is capturing returnable rock samples that could carry signs of ancient microbial life. While Perseverance has a suite of instruments geared toward helping achieve that goal, MOXIE is focused solely on the engineering required for future human exploration efforts.
Since the dawn of the space age, researchers have talked about in-situ resource utilization (ISRU). Think of it as living off the land and using what's available in the local environment — that includes things like finding water ice that could be melted for use; sheltering in caves; or generating oxygen for rocket propellant and, of course, breathing. Rocket propellant is the heaviest consumable resource that astronauts will need, so being able to produce oxygen at their destination would make the first crewed trip to Mars easier, safer, and cheaper.
Mars’ atmosphere poses a major challenge for human life but is well suited for oxygen production. It's only 1% as thick as Earth's atmosphere but it is 95% carbon dioxide, which contains oxygen. MOXIE pulls in that air with a pump, then uses an electrochemical process to separate one oxygen atom from each molecule of carbon dioxide, leaving carbon monoxide as a byproduct. As the gases flow through the system, they are analyzed to check how much oxygen has been produced, how pure it is, and how efficiently the system is working. All the gases are vented back into the atmosphere after each experiment is run.
This electrochemical conversion requires high temperatures — about 1,470 °F (800 °C) — in order to work. To manage those high temperatures, MOXIE, which is a little larger than a toaster, features a variety of heat-tolerant materials. Special 3D-printed nickel alloy parts heat and cool the gases flowing through the instrument, while super-light insulation called aerogel holds in the heat to minimize the power needed to keep it at operating temperatures. The outside of MOXIE is coated in a thin layer of gold, which is an excellent reflector of infrared heat and keeps those blistering temperatures from radiating into other parts of Perseverance.
A full-scale MOXIE system on Mars might be a bit larger than a household stove and weigh around 2,200 pounds — almost as much as Perseverance itself. Work is ongoing to develop a prototype for one in the near future. MOXIE is expected to run about ten times over the course of one Mars year (two Earth years), allowing NASA to watch how well it works in varying seasons. The results will inform the design of future oxygen generators.
Before astronauts can get to Mars, they'll be faced with a critical question: What should they wear on Mars where the thin atmosphere allows more radiation from the Sun and cosmic rays to reach the ground? To determine that, Perseverance is carrying the first samples of spacesuit material ever sent to the Red Planet.
While the rover collects rock and soil samples for future return to Earth, five small pieces of spacesuit material will be studied by an instrument called SHER-LOC (Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals). The materials, including a piece of helmet visor, are embedded alongside a fragment of a Martian meteorite in SHERLOC.
The materials are ortho-fabric — consisting of Nomex, Gore-Tex, and Kevlar — Vectran, which is used in spacesuit gloves, Teflon, and polycarbonate for helmet visors. These materials would be used for the outer layer of a suit that will be exposed to the most radiation.
On Mars, radiation will break down the chemical composition of the materials, weakening their tensile strength. SHER-LOC will help determine how long the materials will last. The device is designed to determine the composition of the Mars rocks the rover collects — the same can be done with spacesuit materials.
A Roving Meteorologist
Mars is about to get a new stream of weather reports. As Perseverance scours Jezero Crater for signs of ancient microbial life, it will provide key atmospheric data that will help enable future astronauts to the Red Planet to survive in a world with no breathable oxygen, freezing temperatures, planet-wide dust storms, and intense radiation from the Sun.
The instrument behind the weather data is the Mars Environmental Dynamics Analyzer (MEDA). Part of its goal is to gather the basics: temperature, wind speed and direction, pressure, and relative humidity. Models of the temperature at Perseverance's landing site range from an average of -126 °F (-88 °C) at night to about -9 °F (-23 °C) in the afternoon.
Together with weather instruments aboard NASA's Curiosity rover and InSight lander, the three spacecraft will create the first meteorological network on another planet.
But a key difference between MEDA and its predecessors is that it will also measure the amount, shape, and size of dust particles in the Martian atmosphere. Dust is a big consideration for any surface mission on Mars. It gets all over everything including spacecraft and any solar panels they may have. It also drives chemical processes both on the surface and in the atmosphere, and it affects temperature and weather. The Perseverance team wants to learn more about these interactions; doing so will help the team planning operations for the Ingenuity Mars helicopter as well.
On Earth, the atmosphere — along with Earth's magnetic field — shields us from radiation. But there is no global magnetic field at Mars, so measuring dust and radiation go hand in hand, especially for spacesuit design. Radiation is probably the most extreme condition for the astronauts, so the suits protecting the astronauts from this radiation will be crucial.
To take its measurements, MEDA will wake itself up each hour, day and night, whether Perseverance is roving or napping. That will create a nearly constant stream of information to help fill the gaps
3D-Printed Metal Parts on Mars
Perseverance is carrying 11 metal parts made with 3D printing; of those, five are in the Planetary Instrument for X-ray Lithochemistry (PIXL) instrument. PIXL shares space with other tools in the rotating turret at the end of the rover's robotic arm. To make the instrument as light as possible, NASA designed PIXL's two-piece titanium shell, a mounting frame, and two support struts that secure the shell to the end of the arm to be hollow and extremely thin. In fact, the parts, which were 3D-printed, have three or four times less mass than if they'd been produced conventionally.
Perseverance's six other 3D-printed parts can be found in MOXIE, which houses six heat exchangers — palm-sized nickel-alloy plates that protect key parts of the instrument from the effects of high temperatures. While a conventionally machined heat exchanger would need to be made out of two parts and welded together, MOXIE's were each 3D-printed as a single piece.
Space Lasers on Mars
When the Apollo astronauts landed on the Moon, they brought devices with them called retroreflectors, which are essentially small arrays of mirrors. The plan was for scientists on Earth to aim lasers at them and calculate the time it took for the beams to return. This provided exceptionally precise measurements of the Moon's orbit and shape including how it changed slightly based on Earth's gravitational pull.
To perform similar experiments on Mars, Perseverance carries the palm-sized Laser Retroreflector Array (LaRA). While there is currently no laser in the works for this sort of Mars research, the device is geared toward the future: Reflectors like these could one day enable scientists conducting what is called laser-ranging research to measure the position of a rover on the Martian surface, test Einstein's theory of general relativity, and help make future landings on the Red Planet more precise.
For more details on the Mars 2020 mission and the Perseverance rover, visit here.