Mass Value Report for May 2025

How is the path to building an interplanetary civilisation looking?

Last week we saw the ninth test flight of Starship, and an update from Elon Musk on the SpaceX plan for colonising Mars. Neither part of the Flight 9 vehicle fully completed its flight, and thus were not able to collect all the data that was needed, but did demonstrate the second ascent of a previously flown Superheavy booster. A similar mission will have to be reflown in a few weeks, delaying fully orbital flights.

This did not dampen the ambitions of the company regarding this program though. I recommend watching the full presentation here on X.

The figures for future flight rates presented were truly astonishing. The aim of 5 ships in 2026 is ambitious (I believe they will have 1-2 myself), but beyond that shows an incredible growth rate:

I’ve estimated LEO mass based on a 100 tonne dry mass, 25 tonne propellant for landing, and 200 tonne payload. I use 4,000m/s as the Δv for a fast Mars transfer. The phenomenal output of Falcon rockets is barely visible compared to what SpaceX are targeting for just 8 years from now. It would represent a compounding 96% growth rate year on year if achieved. They can fall short of this substantially, and still have another revolution in launch on their hands and the capability to start building a Mars base.

Are these plans too grandiose in the context of the recent failures in the test program? How are 500 Starships going to reach Mars if one hasn’t yet reached Earth orbit? Obviously the current issues need to be fixed, and fixed quickly if the 2026 window is going to be used for an unmanned attempt at Mars. But the simple record of test flights doesn’t show the sum of what is going on at SpaceX. The development of Raptor 3 has been proceeding and will improve the performance, and hopefully the reliability, of the vehicle. A second, more robust, launch tower is under construction at Boca Chica which can enable a faster cadence, and a third one is under construction at Kennedy Space Centre. It has been a disappointing first half of the year for anybody invested in the success of Starship, but I still think its a case of when and not if SpaceX solves the issues with the vehicle.

Given that the dates for Starship milestones have already slipped somewhat, some people may be frustrated at the pace of the program. The chart below might put things into perspective though. It shows the delay since the prior launch of every vehicle in this payload class (arguably the Shuttle belongs on here, if you include the orbiter mass in its payload, but that would complicate it too much)

Even with delays, Starship flights are proceeding at a rate comparable to those of the Saturn V at the peak of the Apollo program. I have marked the 3-4 week range that Musk has suggested for future cadence, and it doesn’t seem unreasonable they could reach that based on past performance. If this program appears slow to anybody, its only because its slow for SpaceX.

Blue Origin’s Big Plans

On orbit propellant transfer is not an idea unique to SpaceX - Blue Origin are also racing to develop the technology for their own interplanetary plans. A presentation last week gave some specific about the two versions of the Blue Moon lander, and a new transfer vehicle.