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By Doug Millard on

Up In The Air?

Recently I received an email alerting me to the launch of the United States Air Force’s X-37B spaceplane, a winged, unmanned mini-shuttle capable of reaching orbit and then returning autonomously to Earth.

Earlier that day I had been looking at 1960s military wave rider wind-tunnel models at the Science Museum’s main store.

Two waverider wind tunnel configurations trailing pressure sensor cables
Two waverider wind tunnel configurations trailing pressure sensor cables (V. Carroll)

A wave rider is a particular design of aerodynamic wing – for planes and missiles travelling at hypersonic speeds (at least five times the speed of sound) – in which air trapped beneath the vehicle’s underside actually enhances its performance (no classroom jokes, please).

Problem is, such designs – some were incorporated in the massive XB-70 ‘Valkyrie’ bomber, have never really worked that well.

XB-70A bomber used some wave rider features, 1965 (NASA)

Sunday’s paper carried another story, this time about the launch of the United States Defence Advanced Research Project’s Agency’s (DARPA) HTV-2 or Hypersonic Test Vehicle-2:  an unmanned, rocket-launched, manoeuvrable, hypersonic air vehicle that glides through the Earth’s atmosphere at incredibly fast speeds—up to Mach 20.
On the way home last night I dipped into David Edgerton’s ‘The Shock of the Old’ in which he suggests that some of today’s aerospace technologies are little changed from those of forty and fifty years ago… and still not all they are made out to be.

I expect the latest launches from the USAF and DARPA will also fizzle and pop towards cancellation, like many of their predecessors, their high velocity achievements still only inching us forward at incrementally slow rates.

But, if the novel technologies touted – aerodynamic shape… thermal protection structures… autonomous hypersonic navigation guidance and control systems… prove  truly effective then, just perhaps, we are about to enter a new era of prompt global reach and swift access to space with all the implications that holds.