Photo courtesy of Orbex

The carbon footprint of launching the new Orbex Prime space rocket will be up to 96% lower than comparable space launch programmes, a new scientific study has revealed.

Prime is poised to become one of the most environmentally-friendly orbital launch vehicles ever built, as it will use renewable, ultra-low-carbon bio-fuel and is designed to be reusable.

The company is also committing to offsetting all emissions from the rocket and its launch operations, ensuring every launch is carbon neutral from Space Hub Sutherland, the carbon-neutral Spaceport in the North of Scotland.

The new study by the University of Exeter calculated that a single Orbex Prime launch would produce up to 86% less emissions than a similar-size vertical launch vehicle powered by fossil fuels. This gulf in emissions is primarily due to the similar-size vehicle emitting high levels of black carbon, the particulate matter formed by the incomplete combustion of fuels containing carbon — and a major contributor to climate change when emitted from rocket engines into the stratosphere.

The study also compared the carbon footprint of launching Prime with that of a rocket that is horizontally-launched from a carrier aircraft. In this comparison, the direct launch emissions required by Prime was as much as 96% lower than the horizontally-launched vehicle.

Orbex CEO Chris Larmour said: “Orbex will be the first commercial orbital space launch company to use a renewable, carbon-friendly fuel. We believe it is time to move away from the use of heavily polluting fossil fuels now that more-efficient, sustainable alternatives are readily available, and we hope to see much tighter regulations coming into force.

“As the world prepares to attend the COP26 climate change conference in Glasgow, we have already moved decisively to a fully sustainable solution that avoids the massive carbon emissions profiles of old-fashioned fossil-fuelled launch solutions.”

According to the study by the University of Exeter, a single launch of the Orbex Prime rocket would result in total emissions of 13.8 tonnes of CO₂e. This includes the direct emissions from the launch, the indirect emissions created from the production of the propellent fuels required (biopropane and liquid oxygen), and the radiative forcing (RF) effects of non-CO₂ emissions at high altitude. The carbon footprint is comparable to the average emissions created by one single person in the UK each year.

Orbital space launches using fossil fuels create enormous amounts of black carbon in the upper atmosphere. Annually the amount created by around 120 space launches is equivalent to the black carbon emissions from the entire global aviation industry. Orbex’s solution almost entirely eliminates black carbon emissions.

A key factor in the environmental credentials of Prime is its innovative choice of fuel. The BioLPG used by Orbex for Prime is sourced from Calor, the UK’s leading BioLPG supplier, that produces the propane as a by-product from the waste and residual material from renewable diesel production.

As a result, the Greenhouse Gas (GHG) factor for BioLPG is 90% lower than a fossil-based fuel such as RP-1, the highly-refined form of Kerosene typically used as rocket fuel.

Dr Xiaoyu Yan, of the Environment and Sustainability Institute at the University of Exeter, said: “The UK space industry has a key role to play in combating climate change, for example by launching satellites that can monitor environmental changes on Earth — but such benefits must be weighed against the environmental impact of space launches, which by their nature can be highly carbon intensive.

“Our study shows that the launch operation planned by Orbex can result in a significantly lower carbon footprint compared to the other launch scenarios considered in our analysis.”