– a website dedicated to space exploration, climate change and other topics

– maintained by Dr. Donald Rapp (

- Last updated March 9, 2013


C-60 as a propellant for electric propulsion

The current propellant of choice for ion thrusters is Xe. The purpose of this report is to present results of analyses that estimate the potential advantages of using C60 ("Buckminsterfullerene") as a replacement for Xe.

Initial mass in LEO for human Mars missions (2007)

All of the NASA preliminary plans for human missions to Mars involve transfer of some assets to Mars orbit, and some assets to the Mars surface. A widely accepted surrogate for estimating mission cost for future human missions to Mars is the required initial mass in low Earth orbit (IMLEO). This, in turn can be calculated for any specific mission design by estimating how much mass must be delivered to Mars orbit (MMO) and how much mass must be delivered to the Mars surface (MMS), and multiplying each figure by its appropriate "gear ratio:" mass required in LEO to deliver one mass unit to Mars orbit or the Mars surface.

In Situ Resource Utilization – Lunar and Mars (2008)

In situ resource utilization (ISRU) on the Moon or Mars is an approach for converting indigenous resources into various products (primarily propellants and life support consumables) that are needed for a space mission. Unfortunately, several years ago, NASA stopped funding Mars ISRU (which is practical) and is presently funding lunar ISRU (which appears to be impractical). Furthermore, NASA’s Mars Program does not seem to have any intention of exploiting these water resources for leveraging Mars surface missions.

Life support for human Mars missions (2007)

The requirements for life support for the lengthy excursions involved in Mars missions require further study. This paper makes rough estimates of macro requirements for a crew of six over Mars mission segments.

Lunar ISRU (2006)

It's all just a dream babe, a vacuum, a scheme babe, ... - Bob Dylan – If a committee is allowed to discuss a bad idea long enough, it will eventually adopt it because of all the work they put into it. - K. Kruickshank

Mars Life Support (2006)

Reviews JSC's optimistic estimates for life support for a human mission to Mars and brings them down to Earth (and Mars).

NASA Technology Blueprint (2003)

An official NASA document that provides a prioritized plan to develop technology for NASA missions. The purpose of this Blueprint was to document the technologies required to implement the future missions of the NASA Space Science Enterprise (SSE).

Precision Segmented Reflectors for Sub-Millimeter Astronomy (1992)

Describes how NASA spent $22 million from 1988 to 1992 in an attempt to develop technology for a so-called "large deploy(r)able reflector" - a submm telescope of 10-20 m diameter, and ended up with exactly nothing, and how I nearly got fired for criticizing it.

Propellant Depots in Space (2006)

A discussion of Griffin's proposal to establish propellant depots for space missions.

Radiation effects for human Mars missions (2007)

Describes challenges involved in coping with radiation in human missions to Mars. Radiation in space poses a threat to humans embarked on missions to the Moon or Mars.

Solar Energy on Mars (2005)

Everything you wanted to know about solar energy on Mars.

Solar Power Systems on the Moon (2007)

Everything you wanted to know about solar availability on the Moon and lunar power systems.

Space Solar Power (2007)

Astropolitics journal article on beamed solar power from space.

Space Solar Power, He-3 from the Moon for fusion, and Lunar ISRU (2007)

A report with three separate sections on beamed solar power from space (more detailed than Astropolitics paper), He-3 as a resource for fusion, and lunar ISRU.

Staging and Propellant Depots in Space (2006)

Analysis of proposal to use staging and propellant depots to enable a short-stay mission to Mars. It is shown that the short-stay mission remains impractical, despite claims made in theliterature.

Transporting Hydrogen in Space (2007)

Everything I knew in 2007 about space transportation and storage of hydrogen.

Water on Mars (2006)

Everything I knew in 2006 about water on Mars. Includes temperatures and solar energy onMars, theoretical models of ice stability on Mars, experimental data on detection of water on Mars, and requirements for liquid water on Mars.

NASA Goals for Mars Exploration

The fruitless search for life is a waste of time and taxpayer's money

Published Books:
Quantum Mechanics
by Donald Rapp 1971
Hardcover, 672 pages, Holt, Rinehart and Winston, ISBN 0030812941 (0-03-081294-1)
out of print
Statistical Mechanics
by Donald Rapp 1972
Hardcover, 330 pages, Holt, Rinehart and Winston, ISBN 0030856531 (0-03-085653-1) reprinted 2012
Solar Energy
by Donald Rapp 1981
Hardcover, 516 pages, Prentice-Hall, ISBN 0138222134 (0-13-822213-4)
out of print
Human Missions to Mars
Enabling Technologies for Exploring the Red Planet

Series: Springer Praxis Books
Subseries: Astronautical Engineering

Rapp, Donald
Jointly published with Praxis Publishing, UK
2008, XXXIV, 520 p.

Assessing Climate Change
Temperatures, Solar Radiation and Heat Balance

Series: Springer Praxis Books
Subseries: Environmental Sciences

Rapp, Donald

Jointly published with Praxis Publishing, UK
2nd ed. 2010, 410 p.
Ice Ages and Interglacials
Measurements, Interpretation, and Models 2nd edition

Series: Springer Praxis Books
Subseries: Environmental Sciences

Rapp, Donald

Jointly published with Praxis Publishing, UK
2nd ed. 2012, XX, 410 p. 188 illus., 26 in color.
The Climate Debate

Self published: November 2012

Bubbles, Booms, and Busts: The Rise and Fall of Financial Assets

Springer Copernicus Books 2009