In about a dozen years, Martians could finally arrive on Earth. If it does, it's because we brought her here.
NASA and the European Space Agency are planning a bold mission to collect rock and soil samples from the surface of the red planet and transport them over 34 million miles of space – giving scientists an unprecedented opportunity to investigate what the Mars exists, and to look for evidence that the planet once harbored life. As previous missions have revealed signs of marshes and river deltas, scientists believe they could find the fossils of microscopic organisms that thrived in these lakes and rivers before the planet became the cold desert that it is today Returning samples from Mars starts with the launch of the Mars 2020 rover. As the Rover explores and gathers ground, NASA engineers will continue to develop the technology for the other two phases of the mission ̵
First of all, no one has ever fired a rocket from the surface of another planet. This is a very different scenario from when Apollo astronauts came home from the moon, which is only 238,900 miles away. In contrast to the ascent stage of the Apollo lunar module, the planned Mars Climbing Vehicle (MAV) must free itself from the gravitational pull of a planet, even if the force of attraction is only 38 percent of the earth's surface. And before the ascent vehicle starts home, it has to endure a series of bodily punishments.
First, the MAV is exposed as a payload on a lander on Mars' way to the rough ride of a launch from Earth. This is followed by a six- to nine-month flight through space in a fiery entrance to the Martian atmosphere, a supersonic descent and a not so soft landing culminates. After that, the vehicle will be sitting on the surface for half a year of Mars (equivalent to a full year on Earth) exposed to dust storms, ultraviolet radiation, and temperatures as low as minus 40 degrees Fahrenheit.
Another crucial difference to the Apollo missions: there will not be humans on the spaceship. And because it takes a few minutes for a program to reach Mars, even remote control is out of the question.
"We can not ride the joystick," says Paulo Younse, an engineer at NASA's Jet Propulsion Laboratory. "We can not communicate with him, and we do not have anyone on board, so it has to be automatic."
On February 18, 2021, the Mars 2020 rover lands in the 30-mile-wide Jezero Crater (pronounced "YEH-zuh-raw") and collects there samples in hermetically sealed Tubes cached and can be retrieved later. NASA thought about a landing pad for five years before settling on Jezero. Scientists believe that the crater was filled with a 820-foot-deep lake 4.1 to 3.5 billion years ago. Perhaps more exciting are the signs of a river delta. A delta is "extremely well-suited for obtaining biosignatures, evidence of life that might have existed in seawater or at the sediment-seawater interface, or possibly on things that lived in and flooded in the source region. The rover collects Samples of at least five different types of rocks, including clays and high potential carbonates, to preserve ancient life indicators, be it in the form of complex organic molecules or in the form of fossils of microbes. The search for samples is supported by a range of instruments, including SHERLOC (Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals), which uses spectrometers, an ultraviolet laser, and a camera to detect organic compounds. However, scientists say that this device will not be a substitute for the more sophisticated instruments on Earth, especially when it comes to distinguishing signs of life from chemical activities that might mimic organic processes.
"To really make the next big one If we want to understand Mars as a system, here are some examples," says Charles Edwards, JPL manager for the Mars Exploration Directorate. "Bringing these samples back to Earth can really unleash the power of all terrestrial laboratories and answer some of the questions we want to answer about life on Mars – whether it's extinct life or even existing life."
NASA and the European Space Agency have teamed up to plan later, as yet unscheduled, missions that will eventually complete the Mars sample return. After Mars 2020, the next step is to send another lander with a "fetch rover" and the Mars ascent car to the Jezero Crater. The Rover retrieves the tubes with the rock and soil samples cached by Mars 2020 and then loads them into the payload container of the MAV, a 17-pound cylinder the size of a volleyball. The MAV is then likely to autonomously raise from a horizontal to an upright takeoff position and take off to meet the third part of the mission, an Earth Return Orbiter.
The design requirements of the MAV make it the riskiest part of the mission. Ashley Karp, propulsion director and deputy head of the ascent vehicle at JPL, said the development of the rocket propulsion system was the most challenging technical challenge she had worked on during her seven-year career at NASA. "We have to fit into the entry, sink and landing system to get to Mars, and then be able to start the samples and deliver them to another system," says Karp. "So there are several interfaces."
The propulsion system requires fuel that can withstand the extreme temperatures of Mars while meeting the volume and weight requirements that enable the MAV to fit into a Marslander no heavier than about 880 pounds and no greater than about 10 feet , Over the past two decades, NASA engineers have been using multiple MAV propulsion concepts to discuss two options: a single-stage hybrid rocket engine and a two-stage solid rocket engine.
The main advantage of solid fuel rockets is that the technology is well understood, says Karp. In fact, they've been used on previous missions like Pathfinder, Spirit, and Opportunity to land on Mars. Solid fuel engines are less complex than liquid fuel engines, which require both a feed system and a pressure system or pumps. And because solid propellant is less corrosive and stable than liquid fuel, it can easily be stored for long periods of time.
Hybrid rockets that store the oxidant as a liquid or gas and the fuel as a solid are a more difficult problem to solve. Since 1933, when the Soviet Union launched a rocket that combined liquid oxygen and a solid form of gasoline, engineers tinkered with constructions. Unlike solid rockets, where oxidant and fuel are already combined into a single fuel, hybrid rockets are difficult to safely achieve high thrust because the solid component does not burn fast enough when the liquid oxidizer is sprayed separately during flight. Despite the less developed technology, NASA believes that the potential benefits of a hybrid rocket for a Mars mission are too numerous to ignore. Once a solid rocket is detonated, it must remain lit. A hybrid offers more maneuvering options as it can be throttled, shut down, and restarted in flight.
NASA is optimistic about a hybrid due to a new fuel with a higher burn rate. It is a paraffin called SP7, a waxy solid made from a mixture of saturated hydrocarbons. The oxidant is called MON25 – a liquid oxidizer containing 25 percent mixed oxides of nitrogen.
The problem with a conventional solid propellant is that the extreme temperatures on Mars can cause it to rupture on ignition and possibly explode. If NASA opted for a solid-fuel rocket motor, the lander would have to devote significant effort to keep the MAV warm. In contrast, the waxy SP7 used in a hybrid rocket motor can remain structurally stable under large temperature variations, and the MON25 oxidizer has a freeze point of minus 67 degrees Fahrenheit, which also provides a lot of latitude for the temperature range that is expected Jezero Crater between the landing of the MAV on Mars and the takeoff of a whole earth year later.
At the end of April, the hybrid rocket passed a crucial threshold: a successful ignition at minus four degrees Fahrenheit. "It was the first demonstration that it actually works," says Karp. Two more tests were carried out at the end of July. The first test tested the rocket's quick-fire system for a second fire and a new rocket nozzle, and the second test tested a redesigned SP7 formulation.
Regardless of which MAV design is chosen, autonomous guidance, navigation, and control technologies are required to achieve proper Mars orbit for the Earth Return Orbiter to find. For Evan Anzalone, a naval and navigational engineer at the Marshall Space Flight Center, the initial challenge would be to determine the initial conditions before take-off, exactly where the MAV is on the surface in relation to its destination lane and in which direction it points (his attitude). The attitude of the rocket is determined not only by the direction in which its nose cone points, but also by the rotation speed of the planet and the local gravity.
"The better we can measure these things, the better we can figure out how our original attitude is," says Anzalone. "The problem can be solved, and we have done it with big vehicles, but when you come to this smaller size, you have to do it all autonomously, with a long delay for any kind of orders and coffers."
Anzalone and his colleagues are studying two approaches to guidance, control, and navigation, one called the "open loop," where the rocket is essentially preprogrammed to fly a particular trajectory. "They just give orders to their actuators and go," Anzalone says it's a relatively easy way to launch a rocket, but it carries risks – for example, if the MAV-bearing Mars Lander lands at the Jezero Crater, so the rocket's attitude is only one degree off, then an open guidance system would come along Starting this initial error and the MAV would not reach its destination lane.  In contrast, the other option is the closed-loop guidance, which is a very complicated one second system. In this approach, the missile monitors its position, thrust and velocity during flight, and adjusts where it aligns its nozzle to optimize its trajectory.
Once the MAV reaches the specified orbit, it should release the capsule containing the samples. The Earth The Return Orbiter, which is aligned in the same orbit, would sneak into it at a closing rate of about two inches per second. Probably, the sample container is bright and may have symbols that resemble QR codes, says Paulo Younse, the JPL engineer who designs the detection and restraint system. These features would allow cameras aboard the orbiter to find the destination easier. Up to a distance of 328 feet, air traffic controllers could monitor the approach and possibly make course corrections before the rendezvous. After that, however, "everything is on board [and] the spaceship will fly by itself," says Jeffrey Umland, chief engineer for NASA's current InSight mission to Mars and staff at the capture and containment system.
"We have. That's a very valuable thing, and it has a certain inertia," says Younse. "It moves and turns slowly. The challenge now is to capture this thing in an orbit with a robot, bring it into our system, and package it in a container so we can seal it and bring it back to Earth. We have never done anything so complicated.
While the European Space Agency is developing the Earth Return Orbiter, JPL's engineers design the capture and restraint system aboard the spacecraft.
At the front of this system would be a fishing cone with a series of sensors that would detect when the bin is full. At this point, a lid would quickly close (within two seconds) over the top of the cone, before the container has the chance to hit the back of the cone and hop back into space. "Imagine it more or less as a mousetrap, but we fly to the mouse," says Umland.
Inside the cone, a mechanical arm attached to a paddle swings over the container and pushes it backward of the capture cone and into a containment. Another device, possibly a type of wiper mechanism, would sweep the container to align it so that the sample tubes are stored right-side up with respect to the spacecraft's heat shield. Mission planners believe the hermetic seals on the pipes would have the best chance of survival if they turned away from the direction of travel on reentry and on Earth, possibly at a landing pad in the Utah desert.
This is not science fiction writers have traditionally imagined that Martians will arrive on Earth. If this succeeds, however, we could finally get evidence of life in another world.