Author Archives: Chris Stelter

Space-based Bitcoin Mining

Preface: if you’re a bitcoin expert, gird your loins because I’m probably going to be making a LOT of technical errors in this post. So: space based solar power, but instead of beaming the power to Earth, we mine bitcoin … Continue reading

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Energy needed to get to orbit using various fuels from various planets.

EDIT: I made a big mistake on how I calculate bulk density. I’ll fix it. EDIT AGAIN: I fixed it. I think. I will pick stoichiometric mixes, oxygen as oxidizer and fuels of hydrogen, methane, and carbon monoxide. The three … Continue reading

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Working full time on the Martian surface is within US Radiation Worker limits

The US Radiation Worker annual radiation limit is 5 rem, or 50mSv/year. Divided into the 2000 annual working hours, that’s 0.025mSv/hour. The Mars Curiosity rover measured an average dosage on Mars of 0.67mSv/day at about -4km altitude. That’s 0.028mSv/hour. If … Continue reading

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Homo Cosmicus: Vestibular Implants

EDIT: David Birchler mentioned in the comments that an implant is not required. The technology is called galvanic vestibular stimulation and it can stimulate the sensation of pitch, roll, and yaw. Since surgery is not required, it sounds like this … Continue reading

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Perfectly energy-efficient rocket vehicle

So I was watching a video of a talk by Geoffrey Landis (my old mentor when I was an intern at Glenn), and he made a very interesting point. If you’re trying to maximize energy efficiency for a rocket and … Continue reading

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Reusable Falcon Heavy payload (upper stage staging velocity)

Jon and I were discussing the recent Falcon Heavy payload numbers. Expendable performance to GTO is supposed to be 22 tons (metric, same for the rest of this post). Given how aggressive that is, and given the history of Falcon … Continue reading

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Fundamental cost of putting stuff in orbit: theoretical minimum vs RLV

What is the minimum energy of orbit, and how does that compare to the energy in a chemical rocket’s propellant? Accessing a 150km LEO orbit requires first the energy to get to 150km. That’s roughly (in Energy/mass, or J/kg, aka … Continue reading

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New (?) ideas for utilizing space for business: hypergravity for athletic training

(Note, I had previously written this along with the isotope separation, but wanted to give that idea a chance for discussion first.) Another possible use for hypergravity is for training humans. A big 2-gee facility on Earth would be expensive … Continue reading

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New (?) ideas for utilizing space for business: hypergravity for isotopic enrichment

One night, as I was putting my daughter to bed and waiting for her to fall asleep, I tried to think of some new markets for space utilization. We often hear about attempts to find industrial uses for microgravity for … Continue reading

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SBSP for electric aircraft, cont.

Chris speaking. Along with Jon, I’ve given a lot of thought to this specific application of space-based solar power (SBSP). Yes, there are thousands of aircraft in the air at any one time, but I find this to be one … Continue reading

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