Record flight is step toward HYPERSONIC SPACE AIRSHIP
Ion-drive dirigibles to orbit from aerial 'Dark Sky' base
Behold the Mach 20 hypersonic hybrid ion rocket semi-rigid airship!
The underlying concepts at least of the surface-to-base craft and the Dark Sky outposts themselves seem to be feasible, but JP Aerospace has understandably yet to really do much in the way of flight tests on the mighty orbital rocket airships. Are they really feasible? Can massive gossamer envelopes full of helium gradually boost themselves up to Mach 20+ using slow-acting electrical ion drives (such as those used to keep low-flying satellites up to orbital speed despite drag from the upper traces of the atmosphere)? Even though there's very little air up there, surely a giant, hypersonic rocket airship is a big ask.
Powell recently gave an interview on the subject to nextbigfuture.com, in which he points out that upper-atmosphere weather balloons have already achieved Mach 10 as long ago as the 1960s, so that in his view Mach 20 isn't impossible with modern materials. In fact in his judgement what's called for is not a super-low-thrust but ultra-efficient ion drive, nor a conventional chemical rocket, but rather a hybrid of the two - which he describes as "the most efficient chemical rocket ever, or the least efficient ion rocket". The key issue will be whether enough electrical power can be stored at a low enough weight - either using fuel cells or batteries, solar panels can't do the job - to get the ships up to orbital poke. One cunning aspect of the plan is that the ships will not need any heat shield for re-entry as they will slow down so gradually (using drag in the evanescent upper atmosphere) that no appreciable heating will result.
Powell and his crew certainly don't lack for ambition. The idea is that the mighty Dark Sky floating spaceports would also carry telecoms equipment and tourist hotels to generate additional revenue on top of that gleaned from orbital launch. Their analysis suggests that the hypersonic airships could haul cargo into space for as little as $100 per pound in the near term and eventually just $1 per pound - and Powell sees manned flights to the Dark Sky region as soon as 2013, and permanent inhabited bases there from 2021. He says that JP Aerospace never makes a flight unless it will pay for itself, with revenue coming so far from advertising, telecoms experiments and aerospace tests for companies such as Lockheed.
It's interesting stuff, but progress has been slow - 33 years after commencement Powell and Co and are still doing small unmanned tests on the more achievable parts of their scheme. Larger craft such as the "Ascenders" - more like the massive V-shaped craft envisaged for the future ground-to-Dark Sky leg - are not flying at the moment. We probably shouldn't hold our breath waiting for the hypersonic space airships.
Even so, Powell's team is plainly one to watch, especially in light of the Reg's own aspirations in the rockoon/ballocket space plane arena. ®
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