Nasa is shaking up its Artemis mission to the moon, cancelling a multibillion-dollar Boeing upgrade to the centrepiece SLS rocket and slotting in a test flight closer to Earth as the programme remains beset by delays and cost overruns. The changes announced on Friday mean that Nasa is essentially swapping the actual moon landing for an additional test mission staged closer to Earth – while insisting the 2028 deadline for a lunar touchdown remains unchanged. Artemis III, which was supposed to be...