‘I just mean, you’re not going anywhere until you’ve had a full medical assessment.’

Dorothy opened her mouth to argue, but Sam interrupted her before she could speak, her expression making it perfectly clear that this wasn’t open for negotiation. ‘So as long as I’m Mission Controller then you’ll do things the way I want them done. That means a full medical before I declare you as fit to fly, understood?’

‘Fine.’ Dorothy nodded. ‘Understood.’

From across the cabin, Will was grinning like a Cheshire Cat.

Dorothy just wanted to smack him.

Over the next hour, Dorothy went through the most thorough medical examination she could ever remember. Heart rate and blood pressure were checked and rechecked, blood samples were drawn and sent for instant analysis, she was prodded and probed with all manner of sinister-looking instruments; brain function, liver function, kidney function … While those results were being collated, she’d undergone a hearing test, an eye test, a lung-capacity test.

Now she was on a treadmill, sensors taped all over her forehead and chest, an ECG beeping away alongside her, her breathing being monitored and regulated via an oxygen mask over her nose and mouth.

She was aching, irritated and exhausted.

To make matters worse, Will had been at one side of her briefing her in the details of take-off procedures, landing procedures, emergency evacuation procedures, whilst Sam had been on the other questioning her about her diet, how much exercise she took, how much sleep she was getting …

To cap it all, the television screen on the wall had been running a news story about how the Chinese were almost ready to launch their own intercept craft – the Long March 5B.

Finally her patience came to an end and she stopped running, bringing the treadmill to a halt.

‘What’s wrong?’ asked Will, concerned. ‘Are you feeling OK?’

‘Yes,’ snapped Dorothy, tearing off the oxygen mask. ‘I’m fine. I was fine before, and I’m fine now, and my ability to survive a crash landing on the Moon is not going to be affected by whether I’m currently getting my five-a-day. In the meantime the Chinese appear to be getting ready to start fuelling their probe so shall we just make a decision? Am I fit to fly or not?’

She stood there, breathing heavily, sweat soaking her shirt as Sam and Will stared at each other in silence. Then Sam nodded.

‘You’re fitter than women half your age. There’s nothing that indicates you will have any problem with the stresses of either lift off or re-entry. I’m going to instruct the flight team to start pre-launch checks. We should be good to go in about two hours.’