Scramjet's death plunge puts solar probe on hold

NASA has postponed this week’s launch of its HESSI solar flare probe while
experts work out why an experimental hypersonic aircraft launched on a similar
Pegasus rocket failed last weekend.

NASA had to destroy what could have been the world’s fastest jet aircraft,
the X-43a, just minutes before it was due to attempt a Mach 7 flight. The X-43a
is powered by an air-breathing jet engine called a supersonic combustion ramjet,
or “scramjet”. Instead of using compressor blades, a ramjet uses its speed to
compress oxygen from the atmosphere. A scramjet does this at supersonic speeds
and burns hydrogen fuel.…