The 2026 Nasa budget proposal would slash around US$6 billion (£4.4 billion) in funding. This is a huge reduction, amounting to around 25% of recent Nasa budgets. The savings would mainly come from Nasa science programmes, potentially devastating high profile missions and international collaborations. However, the budget proposal also represents an intentional redirection of Nasa’s focus by government through resource allocation. The state has long supported the development of a robust commercial space sector, and this budget is a further step in that direction. Congress will have the final say and the cost to science could be high if the budget goes through without major amendments. One casualty could be Mars Sample Return (MSR), a joint endeavour with the European Space Agency that is intended to retrieve Martian soil and rock collected by the Perseverance rover and deliver it to laboratories on Earth. An audit of MSR released in February 2024, suggested that the mission’s overall cost could exceed US$7.5 billion (£5.6 billion). The timescale for the mission was also slipping into the 2040s. Nasa …