Op-ed: Without the Moon, There is No Mars
In the spacefaring community, we are facing a question like one that was asked 58 years ago, after a young, optimistic, and visionary US President issued an impossible challenge: send humans to the Moon and back in a timespan of just eight years. Their question was: “how do we go to the Moon?” Our question today, which we ask as twenty and thirty year olds just like they were, is: “how do we go to Mars?” This time, however, we ask this question without the timeframe and inspiring rhetoric set forth by John F. Kennedy.
For our grandparents, the answers were not what they expected at first. Lunar orbit rendezvous was viewed with serious skepticism, but it ultimately proved to be the most effective and economical plan. The Apollo model as a whole was daunting: placing two initially unattached spacecraft on top of a single rocket, more than four times taller and 100 times more powerful than the only human-rated rocket at the time, then leaving one person in Lunar orbit while the other two spend more than a day on the Moon’s surface. Remember, this was conceptualized in the context of Alan Shepard’s 15 minute cannon-shot on a Redstone rocket that had only been tested three times in that configuration. That was point A. The Moon was point B.
Now we have a new point A and point B, but this adventure has more facets thanks to decades of discovering what we don’t know about space. The International Space Station has been a vital asset for discovering and working the problems of long-duration spaceflight. With astronauts like Scott Kelly and Mikhail Kornienko spending a continuous year in space, researchers have acquired knowledge of the detrimental effects freefall has on the human body over an extended period of time. Long-term psychological experiments have been carried out with volunteers staying in a “Mars habitat” together for upwards of a year. Spaceflight contractors and firms are designing vehicles that fly different types of mission profiles to Mars. The aerospace sector stands fairly confident that the hardware and software can be developed for the trip. On the other hand, orbital technology is revealing information about Earth that scientists have not predicted, innovating methods to learn about other planets without astronauts even being necessary. Despite all that, there is an elephant in the room.
We still don’t entirely know how to live on a planet that is hostile to life.
Apollo 17 still holds the record for the longest stay on another world, at just over three days. They relied entirely on supplies like oxygen and water packed onboard their tiny spacecraft. It only took three days to get to the Moon, and three days to get back over to Earth.
The Moon is Earth’s next door neighbor. We can walk over in a few minutes, borrow a cup of sugar and talk for a minute, and return home just as quick as we arrived. Mars, however, is in another neighborhood. It may take 20 minutes to walk there, we would stay for a dinner party, and then another 20 minutes to walk home. That is, unless we drive over in five minutes, but that technology doesn’t practically exist yet. Mars lives in an entirely different orbit than the Earth/Moon system.
The Moon is always the same rough distance from Earth:
Top-down view - the Earth/Moon system, displaying the actual orbit of the Moon (solid line) and its average distance (dotted line). The Moon’s average distance is ~384,000 kilometers from Earth. (Image: Brian Koberlein, courtesy of EarthSky)
As another planet in our star system, Mars has its own orbit, virtually unattached to Earth, meaning it can be on the other side of the Sun:
Top-down view - the orbits of Earth and Mars around the Sun. At their closest possible approach, or “closest opposition,” Earth and Mars are still ~55 Million kilometers apart. Planet sizes not to scale. (Image: University of Oregon)
The safest and most fuel efficient way to Mars is a nine month Hohmann transfer, followed by over a year at Mars, and then another nine month trip back to Earth. The fastest and most dangerous way, which requires tenfold more fuel for every orbital insertion, is a journey of three months between the planets, with the first opportunity to return to Earth just one month after arriving at Mars. Despite the cost and peril of this trajectory, it is still a consideration.
Either way, we are facing much longer than just three days on a different planet, and a mere week and a half off Earth altogether.
We can’t currently send 3+ people on a three year round trip, including more than a year on Mars, with current knowledge on the workings of long-duration space stations. The technology depicted in sci-fi like The Martian or Interstellar is far from reality. We have yet to design and build a Mars lander, habitat station, spacesuit, rover, tools, waste disposal, toiletries, cleaners, sustainable food supplies, oxygen, air scrubbers, etc. The list continues far beyond my expertise.
A consistently underrated item of importance is food. In all previous spaceflights by any agency, food is sent from Earth, either with the crew or onboard an uncrewed supply vessel. For a three year round trip to Mars, packing onboard three meals a day for at least three people is not economical. For three people, that is 9,855 meals. If each meal weighs, say, a kilogram, it adds nearly ten tonnes of mass/weight, not counting extra passengers and contingency supplies. There is also the problem that food loses nutritional value over time. Other problems of this magnitude make Mars further away than it seems.
The Apollo program had its limitations as well. They designed and built spacecraft, rockets, tools, spacesuits, and the like; but they didn’t know how these concepts and procedures would actually work on a real space mission, even with the predictions of engineers and results of Earth-bound simulations.
The Moon was a giant leap, not a daredevil canyon jump. Apollo took risks, but it was not cavalier. Putting people in Apollo spacecraft and sending them to the Moon on the first try was neither safe nor reasonable. They needed to attempt orbital rendezvous, EVAs, long-duration flight, orbital transfers, and tool use in a practical, relatively safe environment to prove their viability. Before Apollo, the Gemini program’s function was to bridge the gap to the Moon, as well as the four Apollo test flights that preceded Apollo 11. Think of Gemini 8, when an unanticipated thruster issue almost cost the lives of Neil Armstrong and Dave Scott; and think of Gemini 9, when Gene Cernan discovered EVAs aren’t as easy as Ed White’s brief excursion made them look. These are only the more immediately dangerous malfunctions that occurred in Gemini. If something of this magnitude goes wrong with the technology for a Mars mission, the crew will need to get back to Earth many times quicker than interplanetary orbital mechanics can allow.
And so, how do we live on the surface of a different planet, and smooth out the risks of a Mars mission? What will bridge our gap? We continue exploring the Moon.
It’s a perfect staging ground, just as low-Earth orbit was in the Gemini program. In terms of how to live on the surface of a hostile planet, the Moon has more in common with Mars than Earth does. It is geologically dead, has less gravity, and no magnetosphere, air, water, or natural familiarity to humans. It floats hundreds of thousands of kilometers away from the nearest Earthling. It requires a spacecraft and launch vehicle to visit. Should there be an emergency, astronauts can punch out and return home in just three days.
Apollo 17 moonwalker and geologist Harrison Schmitt speaks about risk management at the Earthrising Apollo 8 Gala in Hutchinson, KS. He also mentions the average age of the mission control team.
A Moon program will help manage risk. Gemini and the four Apollo test flights did not eliminate the possibility of a problem in future missions, and neither will a Moon program for future Mars missions. However, the bridge programs did reduce the amount of unanticipated problems. As shown by missions like Gemini 8 and 9, and even Apollo 13, the unanticipated problems seem to be the closest calls.
Some say that the first Mars mission should be a one-way trip - that making it to the surface sooner is more important than taking the time to include a way home. Others say that orbital cyclers could be developed to ferry supplies and people back and forth on a reliable timetable. Some even say that civilian volunteers could participate in this permanent settlement. These suggestions seem rather extreme.
I must make clear that I am not an alarmist on the risks of a Mars program. Bridge programs are important, but could be seen by settlement advocates to be costly in hardware and patience. At some point, in the same spirit as Schmitt’s statement at the Earthrising gala, large risk will be involved in a Mars mission regardless of preparation. That point conceded, I posit that much is awaiting to be learned on the surface of the Moon, not only exciting and fantastic discoveries about the Moon itself, but also discoveries about testing and improving our Mars prototypes and hypotheses on a sensible and patient schedule.
The hardest aspects of this Moon program are public support and facing the backlash of settlement advocates. Even in the space community, some believe there is no use in revisiting the Moon; but these beliefs are in the context of the Moon as a destination, not a waypoint. Obviously, there is much to be discovered on the Moon that is unrelated to Mars; but to explain it as such to the taxpayers and lawmakers would ensure that boots will touch neither the Moon nor Mars in the near future. Instead, we must make clear that without the Moon, there is no Mars.
ad meliora
Check out exact dates/times for interplanetary travel using this website:
http://clowder.net/hop/railroad/sched.html
Images and videos courtesy of the Author, except where noted otherwise.
Cover Image: Apollo 17’s lunar rover at Station 8 in the Sculptured Hills, Taurus-Littrow Valley. The East Massif stands in the background. (Photo: NASA AS17-146-22402)
BIBLIOGRAPHY/Suggested Reading:
Aldrin, Buzz, and Leonard David. Mission to Mars: My Vision for Space Exploration. Washington, DC: National Geographic, 2015.
Bennett, Douglas. Polaris Project Evening Star. Dept of Physics and Astronomy, Iowa State University. 2000-2001. http://www.polaris.iastate.edu/EveningStar/Unit7/unit7_sub3.htm.
Burrows, William E. This New Ocean: The Story of the First Space Age. New York: Random House, 1998.
Kelly, Scott, and Margaret Lazarus Dean. Endurance: My Year in Space, A Lifetime of Discovery. New York: Vintage Books, 2018.
Kurson, Robert, Arnold Aldritch, Jerry Bostick, Walt Cunningham, Charles Dietrich, Charlie Duke, Fred Haise, Charles Lewis, Jack Lousma, Jim Lovell, William Moon, Harrison Schmitt, Michael Staab, Frank Van Rensselaer, and Milt Windler. "Earthrising Panel." Lecture, Earthrising: A Celebration of Apollo 8, Kansas State Fairgrounds, Hutchinson, Kansas, December 01, 2018.
Manning, Rob, and William L. Simon. Mars Rover Curiosity. Washington, DC: Smithsonian Books, 2014.
Massa, Gioia. "VEGGIE Program." Lecture, Gioia Massa, NASA Astrobotanist, Florida Southern College, Lakeland, Florida, November 27, 2017. (My article here)
Schmitt, Harrison. Return to the Moon: Exploration, Enterprise, and Energy in the Human Settlement of Space. New York, NY: Praxis Publishing, 2006.
