Category Archives: Orbital Dynamics

Manned Circumnavigation of the Inner Solar System

Posted on April 27, 2026 by Kirk Sorensen

In 1969, a Bellcomm engineer named A. A. VanderVeen published a paper describing a family of trajectories so elegant they seem almost accidental. Fifty-five years later, the most attractive instance of that trajectory family departs Earth in August 2034. This … Continue reading →

Posted in Bigelow Aerospace, Commercial Space, Mars, Orbital Dynamics, Space Exploration, Space Tethers, Variable Gravity | 7 Comments

Queqiao, first use of the powered lunar swingby

Posted on April 19, 2026 by Kirk Sorensen

In 2006, no one had flown the powered lunar swingby to EML2. In 2018, the Chinese did it, and they cited Farquhar while they were doing it. For 20 years I’ve been entranced by the astrodynamic advantages of the Earth-Moon … Continue reading →

Posted in ESAS, Lunar Exploration and Development, Orbital Dynamics | Leave a comment

Gateway is gone, do we need a lunar station?

Posted on April 15, 2026 by Kirk Sorensen

NASA just canceled the Lunar Gateway — the first space station ever planned for EML2. That’s worth reflecting on, because the case for a station at that location has never been stronger. In my previous post I laid out the … Continue reading →

Posted in ESAS, Lunar Commerce, Lunar Exploration and Development, Orbital Dynamics, Propellant Depots, Reusable Lunar Landers, Space Development | Leave a comment

GEO Orbital Debris Mitigation Paper Excerpts

Posted on April 7, 2022 by Kirk Sorensen

Back in 2006, I helped a high-school student (Daniel Rodrigues) who was interested in momentum-exchange tethers to write a paper for a high-school class about a concept for a tether that would remove spent geosynchronous satellites from their orbits quickly, … Continue reading →

Posted in Orbital Debris Remediation/Mitigation, Orbital Dynamics, Space Tethers | 1 Comment

An Updated Propellant Depot Taxonomy Part VI: Roving Depots

Posted on February 22, 2021 by Jonathan Goff

In the last post in this series, I discussed the idea of large-scale depots for human spaceflight applications, which operate in fixed, low-orbits. While the final post in this series will investigate human spaceflight depots that operate in fixed higher … Continue reading →

Posted in Commercial Space, ISRU, Launch Vehicles, Lunar Exploration and Development, Mars, NASA, NEOs, Orbital Dynamics, Propellant Depots, Space Development, Space Exploration, Space Transportation, ULA, Venus | 10 Comments

An Updated Propellant Depot Taxonomy Part V: Human Spaceflight Fixed Depots (Low-Orbit)

Posted on February 16, 2021 by Jonathan Goff

For this next depot taxonomy post, we’ll finally be talking about what people usually think about when they hear the term orbital propellant depot — larger, cryogenic refueling facilities, focused on enabling large-scale human spaceflight missions, performed by a diverse … Continue reading →

Posted in Blue Origin, Commercial Space, Launch Vehicles, Lunar Commerce, Lunar Exploration and Development, Mars, NEOs, Orbital Dynamics, Propellant Depots, RLV Markets, Space Development, Space Exploration, Space Transportation, SpaceX, ULA, Venus | Tagged , , , , , , , | 13 Comments

An Updated Propellant Depot Taxonomy Part IV: Smallsat Launcher Refueling Depots

Posted on November 14, 2020 by Jonathan Goff

After a brief hiatus, I’d like to continue this series with the type of depot I’ve spent the most time thinking about over the last several years, and the first type of depot that really fits the mold of what … Continue reading →

Posted in Launch Vehicles, Lunar Exploration and Development, Orbital Dynamics, Propellant Depots, Space Exploration, Space Transportation, SpaceX, ULA, Venus | Tagged , , , , , , | 6 Comments

An Updated Propellant Depot Taxonomy Part III: GEO Depots

Posted on September 18, 2020 by Jonathan Goff

Of the six depot types I’ll be describing in this series, GEO Depots are probably the least fully-baked of the concepts for me, mostly because I’ve only had limited involvement in the traditional GEO satellite world. But I wanted to … Continue reading →

Posted in Orbital Dynamics, Propellant Depots, Satellite Servicing, Space Transportation | Tagged , , , , , | 6 Comments

An Updated Propellant Depot Taxonomy

Posted on September 15, 2020 by Jonathan Goff

After way too many years in the wilderness, the concept of orbital propellant depots and in-space refueling in general, are finally beginning to be taken seriously again in public circles. A couple of examples include: Elon’s announcement that he is … Continue reading →

Posted in Commercial Space, ISRU, Lunar Commerce, Lunar Exploration and Development, Mars, NASA, Orbital Dynamics, Propellant Depots, Space Development, Space Exploration, Space Transportation, Venus | Leave a comment

FISO Telecon Lecture on LEO Propellant Depots for Interplanetary Smallsat Launch

Posted on November 28, 2018 by Jonathan Goff

Today I gave a lecture on the Future In-Space Operations Telecon Series on the idea of using LEO propellant depots for interplanetary smallsat missions. Here’s a link to the archive page, which has both the presentation itself and an .mp3 … Continue reading →

Posted in Commercial Space, Lunar Commerce, Mars, Orbital Dynamics, Propellant Depots, Space Transportation, SpaceX, ULA | 6 Comments