I checked the latest space news on Saturday with bated breath. NASA had a lot riding on this week’s Orion flight. In a climate of limited budgets and little real public enthusiasm, failure wasn’t an option.
The problem is where Orion goes next. By Cold War standards ambitions are vague; a couple more test flights, fly around the Moon or go to a captured asteroid by 2021-25, and then on to Mars some stage in the 2030s….eventually. Maybe. Both these aims and the time-frame stand at odds with Apollo-era determination when goals, budgets, public support and intent all meshed. I wouldn’t be surprised if Orion flounders before it gets much further, purely because of that mushiness vs public apathy vs budgetary realities.
Which is a pity, because it’s a good spacecraft and the flight on Saturday demonstrated – after two tragic ‘private enterprise’ failures – that the Apollo-era NASA ‘business model’, which rested on private contractors and commercial suppliers – still works. Rocket science is just that – it’s risky, difficult, and stretches materials science. Cutting corners, private-enterprise style, may save money. But when it comes to spaceflight there’s no room for error.
The other point is that Orion is not – as some critics suggest – a retrograde step. Sure, Orion looks like a 1960s capsule. But it isn’t – it’s stuffed with twenty-first century tech. Don’t be fooled by its 2002-era PowerPC 750FX-based computers, either; space computer hardware has to be well proven and rugged. If it fails at the wrong moment, you die. Armstrong and Aldrin’s Raytheon AGC fly-by-wire computer partly crashed when they were descending to the Moon in 1969. But not totally – and it was safe to land.
What’s driving the illusion of Orion being ‘retrograde’, I think, is that we’re conditioned to imagine space ‘progress’ as ‘advance’ from one-shot cone-shaped ‘capsules’, to multi-use winged spaceplanes designed to fly, literally, into space. They were the future, way back when. Except they weren’t. The problem is that the laws of physics don’t co-operate. Mass is everything in spaceflight – dry mass to fuel mass ratio, in particular. The Shuttle orbiter had to lug a LOT of mass into orbit that was useless up there – wings, tail, landing gear, hydraulics, heat shield and so forth. Dead loss for your fuel budget. And that’s apart from the risks of strapping the spaceplane to the side of its booster.
For anything beyond low-earth orbit, you need a vehicle that lacks the encumbrance of aircraft-style flight hardware – but which can still make an aero-braked descent to Earth, because it’s not practical to carry the fuel you need to slow down by rocket. Ideally the spacecraft also has to generate a certain amount of aerodynamic lift, both to steer the descent and to reduce deceleration forces on the crew. The resulting shape is specific, and Apollo, Orion, the Boeing CST-100 and Chelomei’s 1970s-Soviet era VA re-entry capsule all use virtually the same truncated cone design. McDonnell Douglas’ Gemini, Space X’s Dragon, the Soyuz and Shenzhou offer only minor variations on the theme.
Orion, in short, is a recognition of the physics of rocket-propelled spaceflight. Budgets permitting, the 2020s should bring a flurry of similar spacecraft into low-earth orbit – Space X’s Dragon and Boeing’s CST-100, servicing the space station. The Russians (hopefully) will be in on the mix with their late-generation Soyuz. And there’s the Chinese manned programme.
Beyond that, Orion will be on hand to fly to the Moon, a nearby asteroid, and eventually Mars. Orion will not, of course, fly by itself on long-duration missions. It’s good for 21 days in space – enough for an Apollo-type jaunt around the Moon – but for longer flights it’ll be docked to a habitat module. This mirrors the 1968 plan to send astronauts on a Venus flyby using Apollo hardware – the crew would have spent most of the 396 day flight inside a modified S-IVB stage, using the CSM only for the launch and re-entry phases.
Orion, similarly, will be docked with various habitats and propulsion stages depending on mission. The whole stack will become the ‘interplanetary spacecraft’. But all this assumes budget and enthusiasm, among other things (‘other things’ includes finding ways of dealing with radiation, of which more some other time). Bottom line is that state-run space efforts can be killed with the stroke of a political pen.
Perhaps the biggest challenge, then, will be re-selling the excitement of the space dream to a wider public, both in the US and beyond. And this, I think, is where the focus needs to be for the foreseeable future. Space flight is, after all, one of the greatest ventures in the history of the world.
Copyright © Matthew Wright 2014