Scratching the Surface on Planetary Society list!

The Planetary Society’s Emily Lakdawalla publishes an annual list of recommended children’s books about space. Scratching the Surface made it onto this year’s list!

I’m honored to be included with all these other great titles.

Fire from space

The Bighorn Fire has been burning in the mountains near Generation Mars HQ for almost a month. You can see the edge of the city along the bottom and left sides of this image.

It’s an interesting experience to watch a DC-10, flown like a crop duster, painting orange stripes across your mountains, as smoke from the fireline advances toward your city. This satellite image really brings home just how massive this fire is.

How many people?

This is an interesting paper estimating the minimum number of people required for a self-sufficient colony on Mars. Using a mathematical model to estimate work time requirements vs. work time capacity, the researchers come up with a surprisingly low number: 110.

In the forthcoming second book of the Generation Mars series, I peg the colony population at around 5000, so I think I’m good there.


A new study suggests lightning may be weak or nonexistent in Martian dust storms. Researchers vibrated basalt grains at various atmospheric pressures to test their ability to build up charge.

Lightning in a dust storm plays a role in my forthcoming book, Air: Generation Mars, Book One. Hard science fiction is a moving target. Still, the fictional strike in question is weak and only damaging to electrical equipment, so I think it’s plausible.


Launch day

In about two hours, if the weather allows, SpaceX will be launching two astronauts in a Crew Dragon capsule to the ISS for the first time. This is a big deal.

Nine years ago, I watched the last shuttle launch with my kids. The oldest was three years old, and the other was one, so they have no recollection of this. Since then, they have grown to awareness in a world in which the US is incapable of launching its own astronauts into space.

This launch means that will now change. But this launch goes beyond just returning human-launch capability to US soil. That’s cool and all, but focusing on it is a bit short-sighted. This launch marks a turning point in humankind’s relation to space.

SpaceX, with its rapid development of Cargo Dragon, Falcon 9, and Falcon Heavy, has managed to decrease the cost of getting things to space by orders of magnitude. When it is possible to launch lots of stuff cheaply, we’ll launch lots of stuff. Now, with Crew Dragon, SpaceX is going to do that for humans. And when it becomes possible to launch lots of humans cheaply, we’ll launch lots of humans.

Lots of humans and lots of stuff in space means, well, it could mean anything. But mostly, it’s a critical step toward becoming a space-faring civilization. And that’s why this is a big deal.

Keep your eyes up (SpaceX Demo-2)

A year and a couple months ago, I wrote  about the SpaceX Demo-1 mission and why it was so important. That mission successfully sent an uncrewed Crew Dragon capsule to the ISS and returned it to Earth. Then, a little over a month later, a Crew Dragon exploded unexpectedly during a static fire test of its abort thrusters. This delayed a crewed mission, while SpaceX investigated the cause and made corresponding changes to the capsule. As is often and quite accurately said: space is hard.

But the wait is over. Wednesday afternoon (May 27, 2020), at 4:33 EDT, SpaceX will launch Demo-2 to the ISS. Aboard that capsule will be two astronauts, Robert Behnken and Douglas Hurley, the first launched from US soil since the final shuttle launch (STS-135) in 2011.

Keep your eyes up. Times are weird right now, but we will get through this pandemic. And when we come out the other side, we will be well on the way to becoming the space-faring civilization that we are destined to be. Wednesday’s launch is a big step on the path. I urge you to watch the launch, if for no other reason than as a reminder that history is bigger than the mess we’re in right now.

Image: SpaceX

Lava tubes

“This would be the first time any of the children saw the surface. The colonists had built underground, using existing caves and lava tubes where possible, building and burying structures where necessary. This was to protect themselves from solar and cosmic radiation. On Earth, the atmosphere and magnetic field serve this purpose. But Mars has little of either, so dirt and rock filled the role.”
– from Scratching the Surface: Generation Mars, Prelude

A new paper explores lava tubes in the Hellas Planitia as possible habitats for humans.

Middle Grade Treasures

Parents with young readers!

Sixteen authors, including yours truly, have teamed up to offer their books at a discount for a month (April 25 – May 25).

There are some great titles on this list. Please take a look!

Geology of the Moon

The USGS recently released a comprehensive geologic map of the Moon.


Digital versions available at