Meet Mars - The Fourth Planet in The Solar System
Last Updated: August 29, 2023
When thinking of other planets, it’s hard not to think of our red neighbor the next door down. Mars has fascinated us since ancient times and our endeavors into space have held Mars in our scopes time and time again for both remote observation and even direct observation.
In fact, our current goal is to send humans to Mars for the first time by the 2040s. So, what do we know about our red neighbor, Mars?
Introduction to Mars
Mars is the fourth planet from the Sun, orbiting at an average distance of about 142 million miles (228 million kilometers) or 1.52 AU while Earth is 1 AU away from the Sun. It is important to note that its orbit is not as circular as ours meaning that it ranges between 1.38 and 1.67 AU from the Sun throughout its orbit.
Although it has been observed in our sky since ancient times, it was first explored by a spacecraft in 1964 by Mariner 4’s flyby and then when we landed Viking 1 in 1975. Since then it has been explored by landers, rovers, and even probe satellites in orbit around the planet in addition to long-range observatories like telescopes.
Since it is only one stop away and a rocky planet with a more hospitable environment than Venus, it has been the subject of many different research missions delving into topics such as:
- The search for life (past or present off Earth)
- The evolution of Mars’s surface and atmosphere and the potential for similar evolution here on Earth
- The possibility of humans on Mars in the near future and using it as a testing ground and launch pad for other human space exploration misisons
- Developing new technologies for living and working in extreme environments
- Better understanding the formation and evolution of rocky planets
Size (equatorial circumference)
13,233.3 miles (21,296.9 km)
24,873.6 miles (40,030.2 km)
39,133,515,914 miles3 (163,115,609,799 km3)
259,875,159,532 miles (1,083,206,916,846 km3)
12.2 ft/s2 (3.71 m/s2)
32.041 ft/s2 (9.80665 m/s2)
246 lbs/ft3 (3.934 g/cm3)
344 lbs/ft3 (5.513 g/cm3)
1.41 x 1024 pounds (6.39 × 1023 kg)
1.3166 x 1025 pounds (5.97219 × 1024 kg)
All in all, Mars is 1.9 times smaller than Earth, or almost half the size. If Earth were the size of a nickel, Mars would be about as big as a raspberry. Its volume is about 15 percent. Its gravity is less than half of ours. Its density is about 72% of ours and its mass is about 11% of ours.
What’s the surface like?
Dry, rocky, and cold as it is a cold desert planet. At half an AU further away from the Sun than us on average, sunlight takes 13 minutes to reach its surface as opposed to the 8 minutes and 20 seconds it takes to reach us. This also means it’s not quite as bright or warm.
While it appears red due to the oxidation or rusting of iron in its rocks, regolith (Martian “soil”), and dust, the surface actually features a variety of colors including brown, gold, and tan, which we see in “close-up” images. The oxidized dust is easily swept up into the atmosphere and therefore from a distance (such as observing from Earth) appears mostly red.
While Mars has only about half the diameter of Earth, its surface has nearly the same area as Earth’s dry land. This surface, features volcanoes, impact craters, and crustal movement. It has also been heavily eroded and shaped by atmospheric conditions like dust storms.
What about its atmosphere?
Today, Mars’s atmosphere is much thinner than ours, meaning it loses more of the heat it receives from the Sun than us and it cannot offer much protection from impacts from meteorites, asteroids, and comets.
While our atmosphere is primarily Nitrogen and Oxygen, the atmosphere on Mars is mostly Carbon Dioxide (98%), Argon, and Nitrogen with only a small amount of Oxygen and water vapor. This means that spacesuits are required for humans to breathe on Mars. The air would also be hazy and red due to the amount of dust that is suspended in the air versus the blue on Earth.
Surface pressure was found to be equal to about 19 miles (30.5 kilometers) above Earth’s surface during Mariner 6’s flyby.
Is there a magnetic field?
We have found areas of the Martian crust in the southern hemisphere that are highly magnetized, indicating that there was a magnetic field 4 billion years.
However, Mars has no global magnetic field today. In fact, evidence suggests that this loss of magnetic field is intertwined with the loss of its atmosphere and surface water, all effects of some cataclysmic change in Mars’s ancient past.
Is there water?
Today there is water-ice in the polar regions and we have found evidence of briny water flow during seasonal melts. So, yes, there is water on Mars!
There is evidence to indicate there used to be massive bodies of liquid water on the surface of Mars in its ancient past, but those no longer exist today.
Days and Years or Rotation and Orbit
Mars is about half the size of Earth, but completes a full rotation in 24.6 hours. This means that its day is just slightly longer than our own.
With an average distance from the Sun of 142 million miles (228 million kilometers), Mars is 1.5 AU from the Sun, and takes 687 Earth days or 669.6 Mars days called sols to complete its orbit, again keeping in mind its eccentric orbit which varies greatly in distance from the Sun.
Formation and Geology
How did Mars form?
Similar to all other planets in our solar system, Mars formed about 4.5 billion years ago when the centrifugal gravitational forces of the Sun shortly after it started nuclear fusion pulled swirling gas and dust into larger clumps throughout the area that would become the solar system.
Mars Over Time
Our exploration of Mars has continued to show us that the barren cold desert we see today is not the way Mars has always been. In fact, evidence of various forms indicates that Mars used to be very similar to Earth, including having large bodies of liquid water on its surface, a thicker atmosphere, and a magnetic field. Something happened in its past that stripped all of those away. One of the main research interests in Mars is understanding what happened to turn a world very similar to ours to the Red Planet we see today.
As you may have already guessed, if Mars was similar to Earth in its past, it is also one of our greatest contenders for life in some form in the past, present, or future. This is a related topic that is of great interest to scientists and has fueled many of our past, present, and upcoming missions.
What is inside Mars? Is it similar to Earth?
Similar to its fellow terrestrial planets, Mars has a central core, rocky mantle, and solid crust. The ratios are where each planet differs.
Mars core: Between 930 and 1,300 miles (1,500 to 2,100 kilometers) in radius made of iron, nickel, and sulfur
Mars rocky mantle: Surrounding the core is the mantle between 770 and 1,170 miles (1,240 to 1,880 kilometers) thick
Mars crust: Above the mantle is a crust between 6 and 30 miles (10 to 50 kilometers) deep made of iron, magnesium, aluminum, calcium, and potassium
Mar features some of the most interesting topographical features in the solar system!
- Valles Marineris: a massive canyon system as long as the distance from California to New York (over 3,000 miles/ 4,800 kilometers!), 200 miles (320 kilometers) at its widest and 4.3 miles (7 kilometers) at its deepest. All in all, it’s about 10 times the size of the Grand Canyon.
- Olympus Mons: the largest mountain/ volcano in the solar system
- Ancient river valley networks, deltas, and lakebeds indicating the presence of liquid water in its past and a lot of it! In fact, some features suggest there were huge floods about 3.5 billion years ago.
- Polar Ice Caps: While the Martian atmosphere is too thin for liquid water to exist long, there is water-ice just under the surface in the polar regions and some of this flows down hillsides and crater walls in briny saly flows during seasonal melts
Thanks to all the exploration of Mars (explained in more detail later), there are several amazing resources to help you virtually explore the topography of the Red Planet.
- NASA Eyes on the Solar System- Mars
- NASA Visualization Technology Applications and Development (VTAD) 3D model of Mars
- NASA Solar System Exploration Mars Interactive module and Galleries
- NASA Mars 3D Resources
- NASA Solar System Treks
- Wikipedia Template: Features and artificial objects on Mars
Moons of Mars
Phobos is the bigger of the two and orbits closer to Mars. It has many craters and deep grooves. It is slowly moving toward Mars and will either crash into it or break apart from the stress in about 50 million years.
Deimos is about half the size of Phobos and orbits two and a half times further away than its brother. In contrast, Deimos is more irregularly shaped and covered in loose dirt which fills the craters, making it appear smoother.
While Mars currently has no rings, when Phobos crashes into Mars or breaks apart, it could create a dust ring.
Similar to how Mercury’s lack of atmosphere results in drastic temperature shifts from the day to night side, Mars also experiences temperature variations due to a thin atmosphere.
It can be as high as 70 degrees Fahrenheit (20 degrees Celsius) or as low as about -225 degrees Fahrenheit (-153 degrees Celsius). And this fluctuation doesn’t just apply to the day and night side. Heat escapes so easily from the planet that if you were standing on its surface on the equator at noon, it would be 75 degrees Fahrenheit or 24 degrees Celsius at your feet and 32 degrees Fahrenheit or 0 degrees Celsius at your head!
While the atmosphere is thin, there is weather on Mars, primarily in the form of dust storms. As mentioned earlier, the dust is easily picked up from the surface and when winds get strong enough, they can create practically planet-wide dust storms, covering virtually any surface features from view even from large telescopes. Even once these storms officially dissipate, it can be months before all of the dust settles.
Its axial tilt is slightly greater than Earth (25.2 versus our 23.44), creating distinct seasons with slightly more extreme differences. Similar to here on Earth, the season depends on which hemisphere you are in with the Northern Hemisphere having the opposite season as the Southern Hemisphere. Each season is longer since it takes Mars longer to orbit the Sun, but these seasons are not as evenly spread as they are here on Earth. While each season on Earth is about 3 months (a quarter of a year), seasons on Mars vary in length due to the more elliptical, erratic orbit causing it to vary much more in the distance from the Sun than we do here on Earth.
Northern (Hemisphere) Spring/ Southern (Hemisphere) Autumn: 194 sols (Mars days)
Northern Autumn/ Southern Spring: 142 sols
Northern Winter/ Southern Summer: 154 sols
Northern Summer/ Southern winter: 178 sols
Exploration of Mars
Mars has been the most intensely studied planet in the solar system besides Earth. Recorded observations of Mars date back to Ancient Egypt over 4,000 years ago, charting its movements in the night sky. Telescopes greatly increased our understanding of this planet, bringing to light amazing features that fueled our questions regarding life beyond Earth. But that wasn’t enough and as part of the space race, we began sending spacecraft to study Mars in more detail.
The following lists some of the relevant details about successful Mars missions. Failed missions such as Mariner 3, Mariner 8, Mars Observer, Mars Climate Orbiter, and Mars Polar Lander are not included.
Mission Log Dates
Mariner 4 (NASA)
Launch: Nov 28, 1964
1st successful flyby of Mars; Obtained the first close-up images of Mars
Flyby: July 15, 1965
took the first photos of another planet from deep space; closest approach at 6,118 miles (9,846 kilometers); 21 complete photos; clearly showed Mars as a barren planet, unlikely to harbor life as opposed to previous hopes
End: Dec 31, 1967
Launch: Feb. 25,1969
Designed to make a close flyby of Mars to study the atmosphere and surface for signs of life and develop technology for future mission
Preliminary imaging sessions: July 28, 1969
Flyby: July 31, 1969
at a distance of about 2,131 miles (3,429 kilometers); 24 near-encounter photos during a period of 17 minutes; recorded atmospheric pressure, composition, and temperatures
Eventually entered heliocentric orbit and stopped transmitting data
Mariner 7 (NASA)
Launch: March 27, 1969
Twin spacecraft to Mariner 6
Signal Lost/ Problems: July 30, 1969
Just 7 hours before Mariner 6 would be performing its flyby, contact was lost with Mariner 7’s high-gain antenna but connection was reestablished; Likely a micrometeoroid impact
Flyby: Aug. 5, 1969
Despite the damage, it made closest approach at about 2,130 miles (3,430 kilometers); captured 93 far-encounter and 33 near-encounter images of Mars with more topopgraphical details; temperature and pressure readings
End of contact
Mars 2 (Soviet)
Launch: May 19, 1971
The Soviet’s answer to the exploration of Mars; this mission consisted of an orbiter, lander, and rover
Mars Orbit Insertion and Attempted Landing: Nov. 27, 1971
Became second spacecraft to orbit another planet; parachute did not deploy, making them the first lander and rover to impact Mars when they crashed
Orbiter End: Aug. 22, 1972
After 362 orbits
Mars 3 (Soviet)
Launch: May 28, 1971
A twin to Mars 2 with an orbiter, lander, and rover
Orbit Insertion and Attempted Mars Landing: December 2, 1971
Third spacecraft to orbit another planet; first lander to make a soft landing on Mars; transmitted a “gray background with no details” and contact was lost 110 seconds after landing
Orbiter End: March 1972
Mariner 9 (NASA)
Launch: May 30, 1971
Twin to Mariner 8 which failed; 1st spacecraft to orbit another planet; 1st spacecraft to orbit Mars; primary goal: map 70% of the surface during first three months
Entered Mars Orbit: Nov. 14, 1971
Beat the Soviet Mars 2 which had an 11-day head start; became first spacecraft to orbit another world; dust storm inhibited photos
Images began returning: Jan. 2, 1972
Dust storm began subsiding and photos came back clearer including the system of parallel rilles over 1,100 miles (1,700 kilometers) across Mare Sirenum; countered the idea that Mars was geologically inert
All goals achieved: Feb. 11, 1972
Photos and measurements of Olympus Mons, Valles Marineris, and Phobos and Deimos; identified about 20 volcanoes
End: Oct. 27, 1972
Last contact; exhausted fuel; Mapped 85% of the surface at a resolution of 0.5 to 1 mile (1 to 2 kilometers), returning 7,329 photos, including at least 80 of Phobos and Deimos
Mars 4 (Soviet)
Launch: July 21, 1973
Failed to insert into orbit, but returned photos of Mars during flyby on Feb. 10, 1974
Mars 5 (Soviet)
Launch: July 25, 1973
Orbiter reached Mars on Feb. 12, 1974, but lost contact after 9 days in orbit (suspected micrometeoroid hit)
Mars 6 (Soviet)
Launch: Aug. 5, 1973
Flyby and lander with the flyby bus collecting data; lander lost contact upon landing on March 12, 1974
Mars 7 (Soviet)
Launch: Aug.9, 1973
Flyby and lander with the flyby bus collecting data and the lander separating prematurely, failing to enter the atmosphere on March 9, 1974
Viking 1 (NASA)
Launch: Aug 20, 1975
1st of a pair of complex deep space probes designed to reach Mars; orbiter and lander; issues with the first spacecraft caused the second spacecraft (Viking-B) to launch as Viking 1
Mars Orbit Insertion: June 19, 1976
Next day adjusted orbit and began analyzing the primary landing site, but concerns pushed the landing to a site on the western slopes of Chryse Planitia
Landing: July 20, 1976
1st successful landing on Mars; air samples during atmospheric entry; safely landed about 17 miles from planned target; immediately began taking high-quality photos in three colors of its surroundings including a panorama; temperature readings
Soil Samples: July 28, 1976
Robotic arm scooped up the first soil samples and analyzed them for evidence of life which were inconclusive with an unexpected abundance of sulfur
Extended missions: November 1976 to July 1980
Original Extended Mission: November 1976 to May 1978; Continuation Mission: May 1978 to July 1979; Survey Mission from July 1979 to July 1980
Mission Rename: January 1982
renamed the Thomas Mutch Memorial Station in honor of Thomas A. Mutch (1931-1980) the leader of the Viking imaging team who had died Oct. 6, 1980.
End: Nov 11, 1982
Lander stopped operating after a faulty command
Viking 2 (NASA)
Launch: Sept. 9, 1975
Viking-A spacecraft had a malfunction and therefore launched as Viking 2
Mars Orbit Insertion: Aug. 7, 1976
Photos of original landing site indicated concerns, prompting a change to Utopia Planitia near the edge of the polar ice cap
Landing: Sept. 3, 1976
About 4,000 miles from Viking 1; immediate photos showed a rockier, flatter site than Viking 1’s and panorama showed little horizon features
Soil Collections begin: Sept. 12, 1976
Similar analysis to Viking 1: inconclusive evidence of life existing or ever existing
All goals achieved: Nov. 16, 1976
NASA announced both Viking 1 and Viking 2 had successfully accomplished their goals and announced an the extended mission and “Continuation Mission” until July 1979.
Orbiter End: July 24, 1978
Lander End: April 12, 1980
End of transmission; In total, the two Viking orbiters returned 52,663 images of Mars including 4,500 photos of the two landing sites and mapped about 97% of the surface at a resolution of about 980 feet (300 meters) resolution
Mars Global Surveyor (NASA)
Launch: Nov 7, 1996
1st in NASA’s Mars Surveyor Program which planned probes to explore Mars every 26 months from 1996 to 2005; Orbiter mapped the entire surface of Mars in high resolution; Studied Martian atmosphere, climate, and geology
Mars Orbit Insertion: Sept. 12, 1997
One of its two solar panels did not fully deploy after launch, which would be used in aerobraking so the mission was delayed as they reconfigured
Pioneer of Aerobraking: Sept. 17, 1997, to Feb. 19, 1999
1st use of aerobraking to refine a spacecraft’s orbit; first round ended on October 11; second phase was Nov. 1997 to March 1998; third phase began Nov. 1998 to reduce orbit to about 280 miles (450 km)
Announcement of liquid water detected at or near the surface: June 22, 2000
Primary mission end: Feb. 1, 2001
83,000 images of Mars, more than all previous missions to Mars combined
End: Nov 21, 2006
Spent nine years in orbit above Mars; pioneered the use of aerobraking; sent more than 240,000 images; scouted landing sites for Spirit, Opportunity, and Curiosity rovers and Phoenix lander; served as communications relay
Mars Pathfinder (NASA)
Launch: Dec. 4, 1996
Lander and a separate remote-controlled rover to surface; the second of NASA’s Discovery missions to demonstrate innovative low-cost technologies and return geological, soil, magnetic property and atmospheric data
Mars Landing: July 4, 1997
Landed in Ares Vallis; was renamed the Sagan Memorial Station after the late astronomer and planetologist Carl Sagan.
Sojourner Rover: July 5 to 25 Sept. 1997
1st wheeled vehicle to be used on a planet other than Earth; covered hundreds of square miles, returned 550 photos, performed chemical analyses at 16 different locations; showed volcanic rock
End: Sept. 27, 1997
Pathfinder transmitted over 16,500 images and 8.5 million atmospheric and temperature measurements
2001 Mars Odyssey (NASA)
Launch: April 7, 2001
Goal was to analyze its surface and radiation hazards along with a chemical and mineralogical makeup to look for evidence of past or present water and volcanic activity
Mars Orbit Insertion: October 24, 2001
Utilized an unusual aerobraking maeuver to bring it closer and closer to the surface with each orbit until Jan. 30, 2002
Primary Science Mission: Feb. 2002-August 2004
1st global map of the amount and distribution of many chemical elements and minerals in surface; found large amounts of hydrogen, implying the presence of ice deeper below
Ongoing extended operations
Topographical data; found salts in locations where water was once abundant; created most accurate global map of Mars with 21,000 images; communications relay for rovers and landers; help identify potential landing sites and hazards; holds the record for the longest continually active spacecraft in orbit around another planet
Mars Express (ESA, UK, Italian Space Agency, and NASA)
Launch: June 2, 2003
Focused on exploring the atmosphere and surface of Mars from polar orbit; main objective is to search for sub-surface water from orbit
Mars Orbit Insertion: December 25, 2003
Beagle 2 Lander was lost on arrival
Launch: Jun 10, 2003
Together with Opportunity, they were the Mars Exploration Rover Mission of the Mars Exploration Program; main scientific objective was to search for tocks and to look for evidence of past water
Mars Landing: Jan. 4, 2004
Inside the Gusev crater; became known as Columbia Memorial Station
Extended missions: 2004-2010
Visited Bonneville Crater and explored the Columbia Hills
Storms almost end the mission: Summer 2007-Winter 2008
Dust storms in the summer and winter storms covered the solar panels, riskignthe mission if the batteries ran dry without additional power from the panel; in spring 2009 some wind blew off the dust and normal operations resumed
Spirit stuck: May 2009- January 2010
Wheel issues stranded Spirit and after numerous attempts to fix the problems, it was rreformulated as a stationary science platform
Lost contact: March 22,2010
With its current stationary status, a tilt was needed for the panels to access sunlight during the winter, but the tilt could not be achieved and so contact was lost
Attempted contacts end: May 25, 2011
After over 1,300 commands were sent, NASA officially concluded its recovery efforts; In total, Spirit had traveled about 4.8 miles (7.73 kilometers) for over 25 times its original intended lifetime
Launch: Jul 8, 2003
Launched about a month after twin Spirit
Mars landing: Jan. 25, 2004
Meridiani Planum within in an impactor crater named Eagle, on the other side of the planet from its twin; became known as the Challenger Memorial Station
Dust storms: Summer 2007
Science indefinitely suspended as it braved the storm; back in action to enter Victoria Crater Sept. 11, 2007
Milestone: May 20, 2010
Broke the Longest Continuous Operation on Mars record held by Viking 1
Another milestone: May 16, 2013
Broke the Farthest distance traveled by any NASA vehicle on another celestial body record set by the Apollo 17 Lunar Roving Vehicle in December 1972
Another Milestone: March 25, 2015
First Human enterprise to exceed marathon distance of travel on another world
Steppest slope driven by a rover on Mars: March 10, 2016
Near the crest of Knudsen crater, drove at a tilt of 32 degrees; broke Opportunity’s record
Planet wide dust storm: June 2018
Last signal heard on June 10, 2018
End: Feb 13, 2019
Operatied for almost 15 years; explored Martian surface and investigated the geology and mineralogy; Discovered evidence of past water-related environments; exceeded its intended life expectancy by 60 times and traveled over 28 miles (45 km)
Mars Reconnaissance Orbiter/ MRO (NASA)
Launch: Aug 12, 2005
Goals were to map the surface at least partially for future landing sites
Mars Orbit Insertion: March 10, 2006
Aerobraking and engine burns between April 7 and Sept. 11, 2006 to get in final position
Studying Martian surface, atmosphere, and climate; Detected underground ice deposits and served as a communications relay for Mars missions; 2nd longest-lived spacecraft to orbit Mars
Launch: Aug 4, 2007
Goals were to study the history of water in all phases, search for habitable zones, and assessing the biological potential of the ice-soil boundary
Mars Landing: May 25, 2008
Mars Reconaissance Orbiter, 2001 Mars Odyssey, and Mars Express observed atmospheric entry; first time one spacecraft photographed another during a planetary landing; 1st successful landing of a stationary soft-lander on Mars since Viking 2
End: Nov 2, 2008
Lander confirmed the presence of water ice near the Martian pole; Analyzed Martian soil and investigated the potential habitability of Mars; winter severely damaged solar panels, even visible from MRO
Curiosity/ Mars Science Laboratory (NASA)
Launch: Nov 26, 2011
Rover investigating Martian climate, geology, and potential habitability; Car-sized rover about as tall as a basketball player with a 7-foot (2-meter) arm
Mars Landing: Aug. 6, 2012
Gale Crater; named Bradbury Landing site after author of “The Martian Chronicles”
First drive on mars: Aug. 29, 2012
Began exploring and excavating and analyizing samples
Main mission objective found: March 2013
Found evidence of a past environment well suited for supporting microbial life
Discovered evidence of past habitable environments and collected data on Mars’ geological history and potential for ancient life
Softtware update: April 2023
Helps the rover drive faster and reduce wear on the wheels, think while driving, and more
Mars Orbiter Mission (India)
Launch: Nov. 5, 2013
Orbit Insertion: Sept. 24, 2014
End: Sept. 27, 2022
Mars Atmospheric and Volatile EvolutioN/ MAVEN (NASA)
Nov. 18, 2013
Second mission in Mars Scout program; Martian atmosphere measurements to understand climate change on Mars from the past to today; 1st mission dedicated to studying Mars’ upper atmosphere
Mars Orbit Insertion: Sept. 21, 2014
Orbit shift: Feb. 2019
Shifted to a lower orbit to take on additional responsibilities as communications data relay station, particularly for the Mars 2020 rover
Studying how and the rate at which gases are lost to space today to understand the past changes both in the atmosphere and the climate, geology, and geochemistry over time; first spacecraft to make direct measurements of Martian atmosphere; communications relay support for landers and rovers on Mars; designed for 2 years, but has enough fuel to operate through 2030
ExoMars 2016 (ESA and other partnerships including NASA)
Launch:March 14, 2016
Series of missions designed to understand if life ever existed on Mars: Trace Gas Orbiter (TGO) and Schiaparelli Landing Demo
Mars Orbit Insertion: October 19, 2016
Schiaparelli EDL Demonstration Module lost contact shortly before touchdown
Designed to monitor “marsquakes” to better understand Mars’ interior, formation, and activity; brought the first seismometer to Mars; recorded “sounds” of Martian winds for the first time
Mars landing: Nov. 26, 2018
Technology demonstration of Mars Cube/ MarCo CubeSats (microsatellites) deployed in deep space (first of its kind as all previous CubeSats have orbited Earth); launched with Insight lander; the twin satellites were nicknamed EVE and WALL-E after characters from Pixar’s “WALL-E” movie
MarCo End: Nov. 26, 2018
MarCo served as communications relay during Insight’s landing, sending data at each stage in near-real-time; also took images of Mars and performed simple radio science in addition to sending Insight’s first image;WALL-E was last heard from on Dec. 29, 2018; EVE on Jan. 4, 2019.
‘Mole’ Probe mission start: Feb. 28, 2019
Mission was to burrow into the surface to take the planet’s internal temperature and provide more detailed data on the core, mantle, and crust
1st “marsquake” detected: April 6, 2019
Recorded another 730 within the next year
‘Mole’ ended its journey: January 2021
Digging proved to be more of a challenge than expected as it tended to clump, depriving probe of the friction needed to hammer effectively; after multiple attempts with little progress, the mission was ended
Insight End: Dec. 15, 2022
Lost contact, ran out of energy
Hope Orbiter/ Emirates Mars Mission (United Arab Emirates)
Launch: July 19, 2020
Arrived at Mars: Feb. 9, 2021; still operational
Launch: July 23, 2020
Orbiter, lander, and Zhurong rover
Mars Orbit Insertion: Feb. 10, 2021
Landed on Mars: May 14, 2021
Drives on Mars: May 22, 2021
Deployed Zhurong, making it the second nation to land a rover on Mars successfully
Mars 2020 Mission/ Perseverance and Ingenuity Helicopter (NASA)
Launch: Jul 30, 2020
The mission designated Mars 2020 was designed to explore the Jezero Crater, search for signs of past microbial life, collect samples for future return to Earth, and demonstrate new technologies; Conducted detailed investigations of geology, climate, and astrobiology, and carried out the first-ever powered flight on another planet
Mars Landing: Feb. 18, 2021
As of late August 2023, Perseverance has collected 20 of the 38 expected rock samples; over 520,980 photos have been collected
Mars Sample Return (NASA and ESA)
Planned launches: 2027 (orbiter) and 2028 (lander)
A Sample Retrieval Lander will land near or in Jezero Crater (where Perseverance is), bringing a small rocket where the Perseverance samples will be loaded to be sent back to Earth, providing the first collected and returned Martian samples to Earth in 2033
ExoMars 2022/2028 (ESA with other organizations)
Planned launch: 2028
Continuing the 2016 ExoMars mission, this was originally scheduled for 2022 but has been moved for a targeted launch in 2028; It will feature the Rosalind Frankling Rover and work with the TGO to maintain communications; it will be the first European rover
To sum up, Mars has been greatly explored and today, NASA’s current monitoring of Mars includes spacecraft:
- On the ground: landers and rovers including Perseverance, Curiosity exploring Mount Sharp in Gale Crater, Insight probing the interior of Mars from the Elysium Planitia
- In the air: the Ingenuity helicopter was taken to Mars by Perseverance and has made over 50 flights in the Martian atmosphere since it marked the landmark of the first aircraft in history to make a powered, controlled flight on another planet
- In orbit: NASA has three spacecraft in orbit, studying Mars: Mars Reconnaissance Orbiter, Mars Odyssey, and MAVEN
Current international Mars missions include:
- The Hope orbiter from the United Arab Emirates at Mars since Feb. 9, 2021
- China’s Tianwen-1 mission arrived on Feb. 10, 2021, including an orbiter, a lander, and a rover. In May 2021, Zhurong Mars rover touched down, making it only the second nation to do so.
- ESA missions: ExoMars Trace Gas Orbiter and Mars Express
- India: Mars Orbiter Mission (MOM) orbiting Mars since 2014
Explore all of these in real time in Mars Now.
Mars in Popular Culture
No other planet has quite captivated us like Mars. The red dot fascinated our ancient ancestors who bestowed upon it the names of their gods, often relating to war, including the Roman name we use today. Since we first discovered canal-like features on the Martian surface in the late 1800s, many dreamed of intelligent species on the Red Planet, which they believed might be a water world to explain the canals.
Mars in Mythology
The Red Planet was named by the ancient Romans after their god of war since the striking color was so reminiscent of blood. In fact, many other cultures named it relating to the color or related to the feelings or associations with this color. The Egyptians called it “Her Desher” which means “the red one”.
Mars in Literature
Mars has been a setting in fiction since at least the mid-1600s and is easily the most portrayed planet in a myriad of ways in various forms of fiction. Some of the most popular or noteworthy of these works include:
- The 1656 work Itinerarium exstaticum by Athanasius Kircher
- The anonymously published 1839 novel A Fantastical Excursion into the Planets
- Gulliver’s Travels by Jonathan Swift features astronomers studying the moons of Mars over a hundred years before we actually discovered them
- The 1903 novel The Certainty of a Future Life in Mars by Louis Pope Gratacap
- The Barsoom/ John Carter of Mars Series by Edgar Ric Burroughs
- The 1897 novel The War of the Worlds by H. G. Wells
- The 1950 novel The Martian Chronicles by Ray Bradbury
- Joe Haldeman’s 2008 novel Marsbound
- Stranger in a Strange Land by Robert Heinlein
Mars in TV, Film, and Radio
It would be remiss of me not to mention the 1938 radio drama, “The War of the Worlds” which some listeners who really believed the world was being invaded by Martians. While it would be quite exhaustive to list all the movies, tv shows, and more that feature Mars or inhabitants of Mars, here are some famous and notable titles:
- Total Recall (1990 and 2012)
- “The Expanse” TV series based on the novel series by the same name
- The Martian (2015) easily one of the best space and astronaut movies focuses on a stranded astronaut who has to survive on the Red Planet (based on the 2014 book of the same title by Andy Weir)
- Mars Attacks! (1996)
- John Carter (2012)
- War of the Worlds (1953 and 2005) and War of the Worlds 2 (2008)
- Mission to Mars (2000)
- Invaders from Mars (1953 and 1986)
- Robsinson Crusoe on Mars (1964)
- Abbott and Costello Go to Mars (1953)
- Flash Gordon: Mars Attacks the World (1938)
- Marvin the Martian has been a mainstay of the Looney Tunes since 1948 (his design is based on the Hoplite style of armor usually worn by the Roman god)
- “My Favorite Martian” TV Series
Mars in Comics
What’s a better home for Mars than in comic books? Between superheroes and far-off adventures, comic books create the perfect media for imagining the red planet. Here are just a few of the numerous examples of Mars in comics:
- Mars is a 1984 American comic series focused on a group of explorers and engineers sent to Mars to terraform it
- Various John Carter Comics of the famous John Carter from Edgar Rice Burroughs including: John Carter, Warlord of Mars (1977), John Carter: The Gods of Mars (2011-2012), and John Carter of Mars: A Princess of Mars (2011-2012)
- Mars has a rich history within the Marvel universe ranging from ancient aliens who seeded it with light to invasions that Captain America and Golden Girl must thwart to alien space ships and races on and around Mars including the mutant nation of Arakko.
- Similarly, it has also been utilized throughout the DC universe. There are various arcs with invading Martians of various types. It is often most well-known for the Skrulls, particularly the Martian Manhunter J’onn J’onnzz the only peaceful member of his war-like race of conquerors with psionic and shapeshifting abilities. Supergirl even uses Viking 1 as part of her plans to trick Lex Luthor.
- War of the Worlds has been adapted multiple times, first by “Classics Illustrated” in 1955, but other publishers include Marvel, Eternity, and Dark Horse
Mars in Video Games
The popularity of Mars as a sci-fi setting has translated to video games as well. A few notable examples include:
- The Red Faction games
- The 2014 game Destiny
- The Doom games
- Call of Duty: Infinite Warfare
- Daffy Duck: the Marvin Missions
- Mars Rising
- Mass Effect 3
- Surviving Mars
- Monuments of Mars
Mars in Music
Besides the famous bombastic Mars, the Bringer of War sequence in Gustav Holst’s suite The Planets, Mars has also been used in music in a variety of ways, including artist names, including
- The Rise and Fall of Ziggy Stardust and the Spiders of Mars by David Bowie
- Bruno Mars: pop artist
- Charlie Mars: country and folk pop artist
- Thirty Seconds to Mars band
- “Life on Mars” song from David Bowie’s Hunky Dory album
You could also check out the sounds of Mars from NASA
Mars word associations
Did you know Tuesday is actually Mars Day? The ancient Babylonians first created the week and each of the seven days was named for one of the seven known moving bodies in the sky (the sun, the moon, Mars, Mercury, Venus, Jupiter, and Saturn).
While English may not seem to keep this tradition, Tuesday is actually for Tyr, the Norse god of war, or “Tews” the English version. Other languages have kept a more noticeable link to Mars Day such as Mardi in French, Martedi in Italian, and Martes in Spanish.
Did you know the month of March is also named after Mars? While January 1st is New Year’s Day in most cultures today, from Roman times until recent centuries, March was the new year, because it was seen as a time of renewal, of spring from winter. The Romans named this first month of the year after their god of war because the spring weather meant battles could begin.
Observing Mars in the Night Sky
In planetary observing, there are a couple of important terms to remember since we have to consider the location of the desired planet, the Sun, and the Earth to understand how and when the planet will be visible and how. First, astronomers typically group the planets into two subsets to determine their viewing schedule:
Superior Planets: those past Earth going away from the Sun meaning Mars and beyond
Inferior Planets: the two planets closer to the Sun than the Earth (Mercury and Venus)
Then we look at the location of the desired planet, Earth, and the Sun with a few line-ups that determine their visibility:
Planetary Opposition occurs when a planet is directly opposite the Earth from the Sun meaning that they line up with the Earth between the Sun and the other planet. This is typically the best time to view the planets as it is when they will appear the brightest since the planet is the closest to Earth and fully illuminated by the Sun. Only superior planets experience oppositions while inferior planets experience 2 conjunctions. Very close oppositions for Mars occur every 15 to 17 years.
Planetary conjunction occurs when a planet is directly in line with the Sun from the Earth meaning the Sun lies directly in between the 2 planets for superior planets. For superior planets, like Mars, we see the following interactions.
- Superior Conjunction is when the planet is on the opposite side of the Sun from the Earth (behind the Sun from our perspective). The planet appears as a full disk like a full Moon, but smaller since it is further away.
- Inferior Conjunction is when the planet is on the same side of the Sun as the Earth.
Greatest Elongation is when the planet is at its greatest observed angle between it and the Sun when viewed from the Earth. This occurs both in the eastern and western sky. Otherwise, it is too close to the Sun and you can harm your eyes by staring close at the Sun. Make sure that you have a solar filter on telescopes or binoculars to protect yourself.
Quadrature: An elongation of 90° and a planet can be at either the eastern or western quadrature, depending on if the planet lies to the east or the west of the Sun when viewed from the Earth.
Closest Approach: When Mars is closest to Earth. There are many factors to consider here including the fact that both our orbits are not perfectly circular, but rather elliptical or egg-shaped, and more so with Mars. In addition, both of our orbits are tilted. Closest Approach is an ideal time to view Mars typically as it will appear brighter, especially when it lines up with Opposition.
However, with all the variables of our orbits, not all closest approaches are equal. Some will be better than others depending on how the factors line up. In addition, despite the common hoax that is often circulated, Mars will never be as big as our full moon in the night sky. Closest Approaches are also utilized for launching spacecraft to Mars as it takes advantage of the shortest distance between us.
Opposition is the best time to view Mars and other superior planets. The last Mars close approach and opposition was December 2022 and the next will be January 12, 2025 at a distance of 59,703,892 miles (96,084,100 km). Be sure to mark it on your calendar for some good Mars observing.
It’s worth noting that Mars is one of the five planets that can be seen without a telescope.
How to find Mars in the night sky?
Like many other astronomical objects, Mars will not always be visible. Since we passed the last opposition and closest approach in December 2022, Mars has been slowly fading away both in magnitude and whether or not it will be up in the night sky in your location.
For instance, while in late August you should still be able to spy it in the western sky in the early evenings, it will be gone in October, overpowered by the sunset’s glare. It’ll pass behind the sun on November 18, but will be back in the east before sunrise, in early 2024.
Be sure to check out star charts and apps when wanting to spy Mars or other planets. They will all lie in the ecliptic band across the sky, which the sun, moon, and the zodiac constellations pass through, making it often easier to starhop from more noticeable landmarks to the red planet (just make sure it’s not Antares in Scorpius!).
Mars is a fantastic astronomical object for telescope observing, with features to spy. For more information on how to view Mars with a telescope, check out our Observing Mars with a Telescope guide. Check out all of our planetary observation guides for more information on how to observe our celestial neighbors.
We also have planetary conjunctions when a planet appears close to another astronomical object (typically another planet) in the night sky.
Solar conjunction: Nov. 11 to Nov. 25 where Mars will be so close to the Sun it will be invisible to us, making communication with our spacecraft around or on it difficult as data will be inevitably lost. No new commands are given during this time and many instruments will be turned off.
We had a Mercury-Mars conjunction on Autsut 13, but the next upcoming ones are all in 2024.
January 27, 2024: Mercury-Mars
February 22, 2024: Venus-Mars
April 10, 2024: Mars-Saturn
April 29, 2024: Mars-Neptune
July 15, 2024: Mars-Uranus
August 14, 2024: Mars-Jupiter
Since Mars does not lie between us and the Sun, we will not see it pass in front of the Sun from our perspective, creating the opportunity for a transit event.
Summary and Future Prospects
Mars has fascinated us since ancient times and continues to do so. Its close proximity and less toxic environment than Venus has allowed us to explore it up close in orbit, on the surface, and even in the Martian air.
This Red neighbor used to be strikingly similar to us but now lies as a barren icy desert, prompting questions about its evolution and how ours might be on a similar path. Research concerning Mars will continue with an eventual goal of putting humans on the surface by the 2040s, possibly eventually providing at least some of our descendants with a second home or waystation for other human space exploration missions.
Fun Facts About Mars
- Mars is the only planet in our solar system to be completely inhabited by robots!
- According to NASA, if the Sun were as tall as a typical front door, Earth would be a dime and Mars would be an aspirin tablet.
- Phobos and Deimos, the two moons of Mars meaning Fear/ Panic and Dread/ Terror. Some versions say they are the sons of Ares (the greek counterpart of Mars) while other versions say they are the horses that pulled the chariot of Ares.
- Due to the reduced gravity on Mars, you could jump almost three times higher!
- Mars is home to Olympus Mons, the highest mountain in the solar system and 3 times higher than Mount Everest!
- Due to its thin atmosphere allowing heat to escape, your feet could be experiencing spring temperatures while your head experience winter!
Information & Quick Facts
- Discovery: Mars has been known since ancient times and has been observed by many cultures throughout history.
- Name origin: Named after the Roman god of war
- Type: Terrestrial/Rocky
- Category: Inner/Inferior planet
- Diameter: 6,779 km (0.53 times that of Earth)
- Mass: 6.39 x 10^23 kg (0.107 times that of Earth)
- Average distance from the Sun: 238.69 million km (1.52 AU)
- Orbital period (year): 687 Earth days
- Orbital velocity: 24.077 km/s (14.995 miles/s)
- Rotation period (day): 24.6 Earth hours (1.03 Earth days)
- Surface gravity: 3.721 m/s² (0.38 g)
- Surface temperature: -87 to -5 °C (-125 to 23 °F)
- Atmosphere: 96% carbon dioxide, 1.9% argon, 2.6% molecular nitrogen and trace amounts of oxygen, and carbon monoxide.
- Surface features: Volcanoes, mountains, valleys, and impact craters
- Number of natural satellites (moons): 2 (Phobos and Deimos)
- Ring System: None
- Magnetic field: None
- Surface pressure: 6.518 millibars (0.6% of Earth’s at sea level)
- Reflectivity (albedo): Low (about 0.16)
- Exploratory missions: More than 50.
- How long does it take for sunlight to reach it: 13.4 minutes
- Stargazing observability: Very easy
- Planetary protection: Category 3
- Habitability: Not currently habitable for known forms of life, but has potential for future habitability through terraforming or the use of underground shelter.
- Potential for human colonization: Moderate to high
- Evidence of current life: None detected to this day.
Sarah Hoffschwelle is a freelance writer who covers a combination of topics including astronomy, general science and STEM, self-development, art, and societal commentary. In the past, Sarah worked in educational nonprofits providing free-choice learning experiences for audiences ages 2-99. As a lifelong space nerd, she loves sharing the universe with others through her words. She currently writes on Medium at https://medium.com/@sarah-marie and authors self-help and children’s books.
I have compiled 50 questions and answers about Perseverance, a remotely operated robotic vehicle designed to search for signs of ancient life on planet Mars.