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Arrgh! It's not the cost of the fuel
"What's the cost of propellant from earth vs getting it from the moon?" always comes up in discussions of lunar water. Or the cost of near earth asteroid propellant vs earth propellant.Propellant is...
View ArticleWhat's the minimum spin hab?
This post was prompted by Robert Walker's comment: "I wonder what anyone here thinks about my idea for rotating carousels to provide gravity in the lunar colony? Not rotating entire hab, but just a...
View ArticleWho needs humans?
This is in response to Quantum G's question "Why do humans need to return to the Moon to get resources to make "consumables and propellant", if robots can be sent to do that instead?"Just let...
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EML2 plane change
Most of my models use circular coplanar orbits. But Jon Goff points out many asteroids have a healthy inclination. Departing for an asteroid from the moon's orbital plane often involves a big plane...
View ArticleTerraforming Mars vs Orbital Habs
Those who advocate Mars settlement like to say Mars can be terraformed. First I will take a look at what it would take to terraform Mars.How much air do we need to add to Mars?From NASA's Mars Fact...
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The most common delta V error
Patching ConicsTime and time again I've watched people patch conics by using straight addition and ignoring the Oberth benefit. It is a very easy mistake to make. I'll give an example of this error for...
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Murphy's reply
In general, Murphy's followers do not use math. Rather they appeal to Murphy's authority. I am making Mike Stasse and his friend Maponos the poster children for this fallacious argument.Is Murphy an...
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Reusable Earth Departure Stage
My notion of a reusable Earth Departure Stage (EDS) assumes a staging platform at Earth Moon Lagrange 2 (EML2). Propellent, water and air at EML2 might come from an carbonaceous asteroid parked in...
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Travel on airless worlds
When we get to other worlds how will we get from point A to B? There are no roads on Ceres. No rivers or oceans on the moon. No airports on Enceladus or even air for an airplane to glide on.Until...
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Travel on Airless Worlds Part II
This is a continuation of Travel on Airless Worlds where I looked at suborbital hops.The surface of airless worlds will be exposed to radiation so it's likely the inhabitants would live...
View ArticleKerbal Space Program
Lately this blog has been getting some hits from the Kerbal Space Program forum.This looks like a good game. It seems based on the patched conics approach to orbital mechanics. It's good to see a...
View ArticleSpace topics from Dr. Plata
Doug Plata recently suggested some possible space exploration topics. All of them are very interesting.Dr. Plata has good ideas and invests a great deal of time and effort looking at them. He's...
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Will I be banned from Nasa Space Flight Forum?
The largest space forum I know of is forum.nasaspaceflight.com. There are a lot of knowledgeable people who participate including a number of professional aerospace engineers.I enjoy this forum but in...
View ArticleClive Cussler - Two Thumbs Up
I was lamenting to a friend that science fiction is ignoring robotic advances and the near term possibilities they create. He replied "You must read Clive Cussler. I wouldn't call him a science fiction...
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Partial vs full reusability
This is a topic suggested by Doug Plata. What impact will partial reusability have on efforts to settle and exploit space?Reusable Booster stages.SpaceX is working on a reusable booster stage. This has...
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A spiral of tethers
First off let's look at the great granddaddy of vertical tethers, the Clarke tower.For a vertical tether in circular orbit, there's a point where the net acceleration is zero. Above that point, so...
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Potholes on the Interplanetary Superhighway.
Wikipedia describes the Interplanetary Transport Network as "… pathways through the Solar System that require very little energy for an object to follow." See this Wikipedia article. They also say...
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A Golden Escher tribute
Escher loved spirals, the Droste effect, and recursive stuff that suggests infinity.I was looking at a golden rectangle with a series of squares marked off and thought it'd make for a neat variation on...
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The Need for a Better Alpha
What the heck is Alpha?What Alpha am I talking about? A power source's ratio of mass to power. The first time I ran into this quantity was in a NASASpaceFlight discussion of VASIMR's 39 day trip to...
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EML2
Earth Moon Lagrange 2 or EML2 is one of 5 locations where earth's gravity, moon's gravity and so called centrifugal force all cancel out. It lies beyond the far side of the moon at about 7/6 of a lunar...
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