Starship is Still Not Understood

“Starship matters. It’s not just a really big rocket, like any other rocket on steroids. It’s a continuing and dedicated attempt to achieve the “Holy Grail” of rocketry, a fully and rapidly reusable orbital class rocket that can be mass manufactured. It is intended to enable a conveyor belt logistical capacity to Low Earth Orbit (LEO) comparable to the Berlin Airlift. That is, Starship is a powerful logistical system that puts launch below the API.

Starship is designed to be able to launch bulk cargo into LEO in >100 T chunks for <$10m per launch, and up to thousands of launches per year. By refilling in LEO, a fully loaded deep space Starship can transport >100 T of bulk cargo anywhere in the solar system, including the surface of the Moon or Mars, for <$100m per Starship. Starship is intended to be able to transport a million tonnes of cargo to the surface of Mars in just ten launch windows, in addition to serving other incidental destinations, such as maintaining the Starlink constellation or building a big base at the Lunar south pole.”

-Casey Handmer, “Starship is Still Not Understood.” October 28, 2021.

A Drake Equation for Alien Artifacts

“I propose a version of the Drake Equation for Lurkers on near-Earth objects. By using it, one can compare a Search for Extraterrestrial Artifacts (SETA) strategy of exploring for artifacts to the conventional listening-to-stars SETI strategy, which has thus far found no artificial signals of technological origin. In contrast, SETA offers a new perspective, a new opportunity: discovering past and present visits to the near-Earth vicinity by ET space probes.”

—Paul Gilster, “A Drake Equation for Alien Artifacts.” April 20, 2021.

Imagine an alien civilization finding the Voyager space probes a billion years in the future. Over the span of cosmic time, how many other civilizations managed the same? What is the typical civilizational life span of those civilizations capable of doing it?

Then, there is the question of how many would have survived and developed far enough to place probes in nearby stars with environments conducive to life?

The Space Resource Report: 2020

China dominates. Asteroid mining dies but attends its own funeral. Reusable rockets lower the cost and increase access to space. The Moon, Mars, and asteroids all get new survey maps for water resources. Water-based thrusters perform well in orbit. Asteroids are blasted and samples collected. Space mining gets more legal scaffolding. The Moon gets one new rover and two new craters.

The aim of this document is to highlight the major developments surrounding space resources in 2019, with an eye towards following these developments through 2020 and beyond. Let’s get down to the science, business, policy, and real technology developments that will invigorate humanity’s expansion into space.

-David Rich, Joshua Schertz and Adam Hugo, “The Space Resource Report: 2020.” Janurary 24, 2020.

Fairly comprehensive overview. Worth checking out if you have any interest in this topic.

Aerospike Engines

“[A rocket engine] is a heat and pressure machine whose end goal is to convert…heat and pressure into workable thrust. The more that gets converted the better. This conversion is usually done by a large bell nozzle…

The further down the nozzle you go, the lower the pressure and temperature of the exhaust gets and the more it’s exchanged for higher and higher exhaust velocities. So in general, you want this nozzle to be as big as possible in order for it to convert as much of that energy as possible. 

Only one problem. When the exhaust pressure at the end of the nozzle gets below the pressure of the outside ambient air surrounding, the ambient air actually starts to squeeze in on the exhaust gas. Lower the pressure too much and the ambient air will squeeze in on the exhaust so much that it will actually start to peel the exhaust off the nozzle walls and form random shock waves and spikes that will tear apart the engine. So what if you turned an engine inside out and made it so the ambient air pressure is actually pushing the exhaust IN against the nozzle instead of squeezing the exhaust away from the nozzle.”

—Tim Dodd, “Are Aerospike Engines Better than Traditional Rocket Engines?” Everyday Astronaut. October 18, 2019.

I’d never heard of aerospike engines before. This seems like a good introduction.

NASA Image and Video Library

You can browse NASA’s Image and Video Library online; you can also access it via NASA’s API. Through that interface, you can search by caption, keyword, location, photographer, year created, and other fields; in return, you get structured data on each media file. The library was launched two years ago, bringing together more than 140,000 images, videos, and audio files that had previously been spread across dozens of separate collections.