Buzz Aldrin Books

Mission to Mars

MY VISION for SPACE EXPLORATION

With Leonard David, National Geographic Books, Multnomah County Central Library, 629.4553 A3658m 2013

MoreLater, still pondering this book

Dr. Aldrin wants humans to explore Mars. His approach is more rational than most, beginning with teleoperation of robots from Phobos. The mid-term goal still seems to be a permanent and self-sustaining human settlements (p181). Given that it took 4 billion years for evolution to produce our "better of most possible worlds", and a vast interconnected global economy to send a tiny amount of hardware into space (so far), it is difficult to conceive of how a second survivable world can be created on inhospitable Mars.

His timeline for the buildup to this starts before the book was written, after a meeting with President Obama in 2010. Obama's speech saying "by 2025, we expect new spacecraft designed for long journeys ...". In 2017, as I write this, the politician's claims remain grandiose but the progress tiny. Such developments require far more time than a US presidential administration, and every new administration arrives with new speeches and new campaign contributors to fund. Reset the clock, choose different goals, make bigger claims than predecessors, spend more, accomplish little.

Aldrin is correct that a second manned race to the Moon is a waste of time and money. But the Moon is valuable for many kinds of research, and economic development. Throughout history, exploration was soon followed by economic exploitation. If we skip the exploitation part, what justifies the continuing expenditure? The great explorations of the past were driven by profit and power.

On page 20, Aldrin calls for a reusable booster - !SpaceX reused a booster early in 2017, and we will find out how that actually affects the bottom line when Elon Musk runs out of rich folks willing to invest without dividends. Musk seemingly claims he will go to Mars in his Dragon capsule, but even Aldrin's cyclers may be too cramped for this very long journey.

Aldrin hopes for cyclers in 2029, a Phobos visit in 2033 (last color plate) ... starting with a Constellation replacement in 2010. Didn't happen, restart the clock 7 years later. If we have any sort of orbital crew vehicle by the end of 2017, and the cadence of this illustration holds, we might reach the orbit of Mars in 2040, and travel to the surface and back years later, when Musk is in his 70s. Musk may make a attempt to Mars decades sooner, but unless there are miraculous biological advances soon, he will die in the attempt.

Aldrin's schedule is ambitious as well; Mars is 1000 times further away, and the journey will take 70 times as long as Apollo. We will need a lot of capability in place to support the eventual arrival of humans. Phobos is a good first goal; the delta V to Mars surface and back is around 9 km/s, a significant fraction of an Earth/Moon mission with no Mars-local infrastructure to support it.

The best idea in the book is synchronous cyclers, space habitats with shielding and infrastructure to support astronauts between Earth and Mars orbit. The cyclers will still need to be supplied with consumables and propellant, ditto for the Mars outpost at the other end. They will also require "escape velocity plus" delta V to reach at both ends, plus additional thrust on the cycler itself to keep it in an orbit that synchonizes with both Earth and Mars.

I don't expect Dr. Aldrin to agree, but launch loops capable of putting megatons into high orbit would be a good way to assemble a cycler and launch it into its interplanetary cycle, and would have enough delta V to supply a cycler directly as it flies by near Earth. A 5 tonne launch loop could make many launches towards the steadily changing position and velocity of the cycler, with many chances for error ... or cumulative success, assembling kilotonnes of components for cyclers. In time, experience and automation will reduce those errors.

• How much? Gathering material to build a cycler will require many 5 tonne launches from multiple loops. If the sum of the launches are spaced 20 seconds apart, and leave Earth at 2.5 km/s, then the components are spaced 50 km apart. If the cycler assembles over 4 months (10 million seconds) on the way to Mars, and we allow up to 500 m/s delta V to advance or retard each component compared to the whole, AND (handwaving warning!) the 24 hour turn of the launch loop perigee can be accomodated somehow, then we can "close up" this constellation of components over a distance of 5 million kilometers to each side. That is 1e7/50 times 5 tonnes or 1 million tonnes.
• This is probably WAY too optimistic - the Earth does indeed turn, and so the "launch window per day" may be 10% of the whole, and other problems may add another factor of 10; we might have only 10,000 tonnes to work with. Much of that will be propellant, which with proper design will double as shielding. So will food, and so will the excrement made from that food.

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Page 154-157 of the book discusses telepresence in hopeful words. Me mentions UT Austin astronomer Dan Lester as a champion of exploration telepresence, and S. Fred Singer as an advocate of surface landers controlled from Phobos or Diemos via relay satellites. From Phobos, I figure that to be a 39000 km, 130 millisecond round trip, as opposed to a 0.7 hour round trip from Earth; an excellent opportunity for telepresence. If we develop 2.7 second predictive-adaptive telepresence from Earth to Moon, and 50 millisecond lunar orbit-to-surface telepresence, we will have excellent tools to do this.

Namedrops

• p002 Ares/Constellation, Altair lander
• p019 Sierra Nevada Dream Chaser
• p021 Starcraft Boosters, Hubert Davis, flyback booster
• p023 Orion spacecraft by Lockheed-Martin, mostly disposable, Aldrin:-(
• p029 Unified Space Vision p31 human presence on Mars by 2035
• p032 launch Orion on Delta IV, cancel Ares
• p034 early sketch of Aldrin cycler - James Longuski Purdue, Damon Landau JPL
• p037 Aldrin XM, exploration module, up to 3 years p38 2018 one year flyby of 46P/Wirtanen
• p038 2019/20 2001 GP2, 2021 99942 Apophis (250m, possible 2036 impact, 2029 diversion mission)
• p041 Buzz Basics: Aerocapture, Radiation Protection, Closed Loop Life Support

• p046 United Strategic Space Enterprise think tank, ShareSpace raffle, International Space University, Bigelow Aerospace inflatables

• p051 Space tourism, p54 Zero Gravity Corporation parabola flights
• p063 Bigelow inflatible 2100 m³, 2x ISS
  • khl: if ISS is 1050 m³, typical crew of 6, that is 175 m³ per astronaut
  • khl: "Space Ship Earth" is 5.1e14 m², 7.38 billion people, scale height 8500 meters, so that is 5.9e8 m³ per person. If we limit "Earth Space" to moderately inhabited land (10% WAG) and 3 meters vertically, that is 207

32 m³ per person. My (underpopulated) house, including basement business/lab/library, is 320 m³ per inhabitant. So, space station is as crowded as a family home, but vastly smaller than the biosphere that surrounds all family homes, per inhabitant. How much room do people need? Biosphere 2 was 2.5e4 m³ per inhabitant, and lethally inadequate to support them. Though some (who have never built a closed environment) believe they can do am uch better job.

• p124 B612 Rusty Schweikert Sentinel NEO finder