# Rockets and human power: Correlation Prices it moves with, and why Source page: https://www.materialinsights.org/energy/e_rockets/correlation/ Rocket launch cost depends on reusability, engines and airframe materials far more than propellant. Bicycles and human power run on food, so their energy links to crop prices, while frames use aluminium, steel and carbon fibre. No public price Rockets and human power has no public monthly price series: Launches priced per mission; bicycles are consumer goods with no single index. #### What its price moves with Energy [Exp Explosives and propellants](https://www.materialinsights.org/energy/e_propellants/)Fuel Rockets burn propellants such as kerosene, liquid hydrogen, methane and solid fuel mixtures. Propellant is a modest part of launch cost, so cheaper launches come from reusing rockets rather than cheaper fuel. Rockets have no price series, so no statistics are shown. Not enough overlapping price history to measure. Chemical [O2 Oxygen](https://www.materialinsights.org/chemicals/oxygen/)Oxidiser Most liquid rockets carry liquid oxygen, made by air separation plants that also supply steel mills and hospitals. Oxygen is cheap per launch, but large launch programmes need dedicated supply near the pads. Not enough overlapping price history to measure. Chemical [H2 Hydrogen](https://www.materialinsights.org/chemicals/hydrogen/)Upper stage fuel Liquid hydrogen gives the highest efficiency of common rocket fuels and powers many upper stages. It is costly to make and store very cold, and supply comes from the same plants serving industry. Not enough overlapping price history to measure. Energy [Ref Refining and reforming](https://www.materialinsights.org/energy/e_refining/)Kerosene supply Many first stages burn RP-1, a highly refined kerosene made in refineries from crude oil. Its price follows oil and refining margins, but fuel is a small part of launch cost, so this link matters little to launch prices. Not enough overlapping price history to measure. Commodity [Al Aluminium](https://www.materialinsights.org/commodities/aluminum/)Airframe and frames Rocket tanks use aluminium-lithium alloys, and many bicycle frames are aluminium. Both rely on aluminium sheet and tube, whose price follows electricity costs at smelters and global industrial demand. Lighter alloys raise payload, so aerospace grades carry a premium. Not enough overlapping price history to measure. Energy [Mu Muscle power](https://www.materialinsights.org/energy/e_muscle/)Human power Cycling turns food energy into motion through human muscle, one of the most efficient forms of transport. Its fuel cost is the price of food, linking this energy use to crops rather than to fuel markets. No public price for muscle power, so the link is explained in words only. How to read these numbers **Correlation of monthly changes** (the number in the coloured pill) compares how much each price moved, month by month, since 2006 or the first month both series exist. It runs from −1 to +1: near +1 the two usually rise and fall in the same months, near 0 there is no link, and a negative number means they tend to move in opposite directions. Above 0.7 is strong, 0.4 to 0.7 moderate, 0.2 to 0.4 weak. **12-month changes** compare year-on-year moves, which shows whether two prices share the same cycles even when the month-to-month noise differs. **Price function** is a straight-line fit of the two prices on logarithmic scales: price ≈ k × (partner price)^β. β is how much this price moves, in per cent, for a 1% move in the partner over the whole period, and R² is the share of the variation the fit explains. Two prices that both drift up with inflation can fit well without any real link, so read it together with the monthly correlation. **Lead or lag** checks whether the monthly correlation is clearly higher when one price is shifted by 1 to 6 months. Correlation is not cause. The reasons on each card explain the economic link; the numbers show how strongly it has shown up in prices. Proxy series are US producer price indexes or related prices and can blur the real link. Data: World Bank Commodity Price Data (Pink Sheet), October 2026; US Bureau of Labor Statistics producer price indexes, IMF primary commodity prices and US EIA prices via FRED, Federal Reserve Bank of St. Louis, retrieved November 2026. Calculations by this site. ## Other sections - [Summary](https://www.materialinsights.org/energy/e_rockets/index.md) - [Overview](https://www.materialinsights.org/energy/e_rockets/overview/index.md) - [Science and limits](https://www.materialinsights.org/energy/e_rockets/science/index.md) - [Value chain](https://www.materialinsights.org/energy/e_rockets/valuechain/index.md) - [Unit economics](https://www.materialinsights.org/energy/e_rockets/economics/index.md) - [Engineering methods](https://www.materialinsights.org/energy/e_rockets/methods/index.md) - [Equipment and suppliers](https://www.materialinsights.org/energy/e_rockets/equipment/index.md) - [Relationships](https://www.materialinsights.org/energy/e_rockets/links/index.md)