Elon Musk’s Plan to Settle Mars [R.Zubrin]

By Dr. Robert Zubrin, National Review, 02.22.20

Last week my wife Hope and I traveled to Boca Chica, Texas, to meet with Elon Musk. While we talked inside the SpaceX onsite headquarters, a mariachi band played outside, providing entertainment for long lines of people queued up to apply for multiple categories of jobs building craft to take humans to Mars. Hundreds were already hired and at work in the complex. Soon there will be thousands.

Musk calls his design the “Starship.” It’s a methane/oxygen-driven, stainless-steel, two-stage-to-orbit rocket with a payload capacity equal to the Saturn V booster that sent Apollo astronauts to the Moon. The Saturn V, however, was expendable, with each unit destroyed in the course of a single use. Starship will be fully reusable, like an airliner, and therefore promises a radical reduction in payload-delivery costs.

Starship has yet to be demonstrated. Yet here was Musk, building not the first experimental ship to prove the concept but, as we witnessed touring the place the next day, a shipyard and a fleet. Is he mad? According to conventional aerospace-industry thinking he certainly is. But there is a method to his madness.

I have known Musk for some two decades now. In 2001, I was among those who helped convince him to make Mars his calling. His plan is based to a significant degree on my own work, which is generally known as the Mars Direct plan. Published in 1990 and elaborated in detail in 1996 in my book The Case for Mars, Mars Direct was a radical break with previous NASA thinking on how human Mars missions might be accomplished. But Musk’s Starship plan is far more radical still.

With the exception of a period in the 1990s when NASA, under the guidance of Mike Griffin, the associate administrator for exploration, did embrace an expanded version of Mars Direct, the space agency has stuck with a paradigm set forth by Wernher von Braun in a number of variations between 1948 and 1969. According to those ideas, orbital stations should first be built, providing platforms for on-orbit construction of giant interplanetary spaceships using advanced propulsion systems, which would travel from Earth orbit (or currently, rather more absurdly, lunar orbit) to Mars orbit. Departing from these orbital motherships, small landing craft could take crews down to the Martian surface to plant the flag, make a few footprints, and then return to orbit after a short stay.

In contrast, both Mars Direct and the Starship plan use direct flights from Earth orbit to the surface of Mars, with direct return from the surface to Earth using methane/oxygen propellant made on the Red Planet from local materials. Both plans shun any need for orbital infrastructure, orbital construction, interplanetary motherships, specialized small landing craft, or advanced propulsion. Both involve long duration stays on Mars from the very first mission. For both, the central purpose of the mission is not to fly to Mars but to accomplish something serious there.

But there is a difference. In Mars Direct, the modest earth-return vehicle and the crew’s habitation module both stage off the booster that delivers them to orbit, landing on the Red Planet with a combined useful-habitation-plus-payload-mass of about 40 tons. In Musk’s plan, a Starship is flown to orbit and then refueled there by six tanker Starships, after which the whole ship is flown the Mars, delivering a useful habitation-plus-payload mass of as much as 200 tons. So, while the Mars Direct plan might send crews of four to six astronauts at a time to the Red Planet, a Starship could accommodate 50 or more.

Musk’s plan offers more mission capability than Mars Direct does, but that capability comes with a price. Specifically, if the crew is to come back, you need to refuel a Starship, which needs about 1,000 tons of propellant. In the Mars Direct plan, the much more modest earth-return vehicle sent to the Red Planet in advance of the crew requires only 100 tons. The Mars surface-power and other base requirements needed to support Starship operations are a factor of ten higher than those needed to implement Mars Direct.

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