Semi-Cycling and the Martian Export Market - Philip Baldock - 2021 Mars Society Virtual Convention

Track Code: TE-3

Abstract:
Before a Mars colony can reach self-sustaining sizes it will find itself with a large population completely dependent on expensive technology imports from Earth. Somehow this must be paid for. This project suggests a novel approach towards dramatically decreasing export cost from the Mars system to Earth’s orbit. Using material from Deimos to make products instead of Mars itself and novel orbital manoeuvres (via L1 Halo orbit) requires around 5 times less delta v for exporting goods compared to launching from Mars’ surface, aided also by lower thrust requirements (fewer engines). For the other half of successful export to Earth, cheap aerocapture at Earth’s atmosphere, a large reusable nickel superalloy spacecraft (a "semi-cycler") travels with the freight to aerobrake just enough for elliptical orbital capture. Its large size permits aerobraking without the use of disposable heat shields and greatly simplifies maintenance. Inbound freight from Mars now captured in a steep ellipse and detached from the semi-cycler, this freight can then gently aerobrake without the semi-cycler over many passes until low Earth orbit is achieved. The detached aerobraking spacecraft follows a steep ellipse to Sun-Earth Lagrange point 1, loitering until the next launch window where it launches outbound to double as a cycler-style living space for Earth-Mars passengers, hence the name semi-cycler. Storing orbital energy at a Lagrange point enables minimal outbound fuel costs and launch date flexibility. Together, the semi-cycler and use of Martian Moons for source material may provide as much as 50 times lower export costs than shipping naively from the Martian surface, making an entire new industry possible. The export of thousands of tonnes of satellite components and other goods at a profit from Mars could thus enable much quicker development of a Mars colony.

From the 24th Annual International Mars Society Convention, held as a Virtual Convention worldwide on the Internet from October 14-17, 2021. The four-day International Mars Society Convention, held every year since 1998, brings together leading scientists, engineers, aerospace industry representatives, government policymakers and journalists to talk about the latest scientific discoveries, technological advances and political-economic developments that could help pave the way for a human mission to the planet Mars.

#MarsSociety #MarsSocCon2021

[alangknowles]

Best presentation so far.
Clear and consise.

[tonyruiter]

Great talk Philip, clear and well presented. My own takeaway\synopsis of the talk : A plausible way of using orbital mechanics and aerobraking (cycler) to transport material from Mars surface to future Earth industries in LEO for perhaps $55/kg.

[theOrionsarms]

Making things around Mars from raw materials of Deimos or Phobos makes sense, but that would be made from the beginning, I am thinking about starship in particular the plan is to send 100 tons of starship with 100 tons of payload and 230 tons of propellant, and not only for the beginning but forever and for always, why? If you send only starship with almost a empty tanks you could put 350 tons of payload and have the same mass of aerobreacking on Mars for capturing into orbit.

[regolith]

Excellent presentation of an excellent idea. Thought-provoking and plausible. Extra points for being devoid of silliness like “wet workshops”.

[MindeyI]

Another thing that Phobos and Deimos are useful for -- as in-orbit construction material for very large generation-ships to be sent out to other star systems. Who would pay for that? Well, those who want to go (the culture of explorers).

[bernardsegonnes]

When coming back from Mars or the Moon, why do you want to directly do a 'brutal' aerobreaking and land ?
Wouldn't it be safer/cheaper/reusable to tale more time, circle the Earth to slow down ? And land like if you came from the ISS ?

[THX..]

Part of Elon Musk's design philosophy is the best part is no part...IMO the best propellant is no propellant. The cheapest possible way to move cargo from Mars to Earth is to build mass drivers on Mars and Phobos. You use mass drivers to launch materials from Mars to Phobos, then from Phobos to Earth, the Moon, Lagrange points or wherever you like. Then the only propellant you need is to decelerate....Not sure a mass driver would work well on Earth due to our thick atmosphere, but a mass driver on the moon would work well to move cargo from the Moon back to Earth and on to Mars or wherever else in the solar system we want to send stuff.

[stevemickler]

Beam powered propulsion is hardly science fiction and can achieve high Isp and high thrust. A microwave or laser beam powers a AFMPD electric engine. Launch windows expand and trip times get much much shorter. If solar power sats in Mars orbit are used to power the colony they can also power surface to orbit shuttles, aircraft and surface vehicles. I stand amazed at the stunning failure to embrace this obviously superior technology.. Want to add that beam powered propulsion for shuttles could be an electric or directly beam heated ramjet so no propellant need be made.

[RicksPoker]

So it takes ~1 km/s to go from Mars L1 to Earth L1. But you still need to launch the manufactured goods from Mars surface to the Mars L1 halo orbit.

I see the advantage of doing this in two steps, (you can fill up your cycler at your leisure for one thing), but you still have the delta vee of the Mars launch to add into your costs.

If the author reads this, could you discuss?

Warm regards, Rick.