How long does it take to get to Mars?

Mars is the most habitable planet in the Solar System after Earth. But how long does it take to get to Mars? Depending on the technology, the red planet’s position, and some other things, somewhere between 150 to 300 days.

Once every two years or so, Mars and Earth reach their closest points, with the red planet being as close as 55 million kilometers / 34 million miles.

Many space agencies have taken advantage of this orbital alignment and sent many spacecraft to Mars. The journey usually takes between 150 to 300 days, depending on the speed of the launch, the alignment, and the length of the trip.

Another critical factor is how much fuel the agencies are willing to burn to get there. The more fuel they have at their disposal, the shorter the travel time.

Journeys

In 1964, the first spacecraft sent to Mars, named Mariner 4, successfully reached the red planet in just 228 days. NASA sent it on November 28, 1964, and it arrived on July 14, 1965.

Here is a list of other successful missions and their flight time:

  • Mariner 6 – 1969 – 155 days – a flyby
  • Mariner 7 – 1969 – 128 days – a flyby
  • Mariner 9  – 1971 – 168 days – First spacecraft to orbit Mars
  • Viking 1 – 1975 – 304 days – First U.S craft to land on Mars
  • Viking 2 – 1975 – 333 days – Orbiter & Lander
  • Mars Global Surveyor – 1996 – 308 days
  • Mars Pathfinder – 1996 – 212 days
  • Mars Odyssey – 2001 – 200 days
  • Mars Express Orbiter – 2003 – 201 days
  • Mars Reconnaissance Orbiter – 2005 – 210 days
  • Phoenix Lander – 2008 – 295 days
  • Mars Science Laboratory – 2011 – 254 days
  • Curiosity Lander – 2012 – 253 days

There are many more than the list mentioned above. Some have failed to reach the red planet; others are still there to this day, and they are gathering information.

Why does the journey to Mars take so long?

Theoretically, a spacecraft is usually traveling at 20.000 km / 12.427 mi per hour, and thus it should reach the red planet in about 115 days, but this isn’t the case.

This is because both Mars and Earth are orbiting around the Sun. A direct traveling path is impossible since Mars is also moving. Thus agencies usually launch their spacecraft in the direction of where Mars is going to be.

Another constraint is fuel. The needed fuel for a direct path would be too much, an almost impossible amount. NASA engineers use a method of travel called a Hohmann Transfer Orbit – or a Minimum Energy Transfer Orbit – to send a spacecraft towards Mars using the least amount of fuel.

This technique was proposed since 1925 by Walter Hohmann. It involves boosting the orbit of the spacecraft so that it’s following a larger orbit around the Sun than Earth. This will eventually intersect with the orbit of Mars at the exact moment. To use even less fuel, you just take longer to raise your orbit and increase the journey towards the red planet.

Other Methods of Decreasing Time Travel

It is clear that in the future, we want to send people to Mars; however, the length of the journey might pose a longterm health risk to astronauts due to space radiation.

Solar storms are also a huge risk factor since they could kill unprotected astronauts in just a few hours. Decreasing the time travel is essential for a successful human-crewed mission to Mars. Here are some ideas that scientists are working on to solve this issue:

Nuclear Rockets

Nuclear rockets heat a working fluid like hydrogen, for example, to intense temperatures in a nuclear reactor and then blasts it out at high velocities creating a thrust.

Since nuclear fuels are energetically denser than chemical rockets, a higher thrust velocity is possible with less fuel. Some propose that the nuclear rockets could decrease the travel time to Mars down to about seven months.

Magnetoplasma Rockets

This technology, called Variable Specific Impulse Magnetoplasma Rocket or VASIMR – is an electromagnetic thruster that uses radio waves to ionize and heat a propellant.

The ionized gas called plasma can be magnetically thrust out of the back of a spacecraft at high velocities. A former astronaut named Franklin Diaz pioneered the development of this technology.

A prototype is expected to be on the International Space Station to help maintain its altitude above Earth. If such a technology would be used on the mission to Mars, a VASIMR rocket could reduce the travel time down to five months.

Antimatter Rockets

This is the most extreme proposal on the list. Antimatter is created in particle accelerators, and it is the densest fuel one could use. When atoms of matter and antimatter meet, they transform into pure energy.

This was predicted by Albert Einstein’s famous equation, E = mc2. Only 10 milligrams of antimatter would be needed to propel a human mission to Mars in only 45 days. Though it is a small amount, to produce 10 milligrams of antimatter would cost around $250 million.

Future Missions to Mars

Many astrobiology missions are planned for the red planet, including the Mars 2020 and Rosalind Franklin rovers. They have the task of taking soil samples and return them to Earth for further analysis. 

If we look into Mars’s history, it is one of the most actively observed planets in the Solar System, and chances are it will remain so for a long time.

Did you know?

  • Mars is around 50% farther from the Sun than Earth.
  • You would need around six Mars-sized planets to fill the volume of Earth.
  • The red world is the outermost terrestrial planet in the Solar System, outside Earth’s orbit.
  • If you wanted to fill the Sun with Mars-sized planets, you would need around 7 million of them.
  • If you were on the surface of Mars, the Sun would appear half its size in the sky compared to how it is seen on Earth.
  • A Martian year is almost twice as long as an Earth year.

Sources:

  1. Wikipedia
  2. NASA
  3. Universetoday
  4. Space

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