Actually, it is rocket science Virgin Galactic
Posted by Unknown
on November 8, 2014
SPACE flight is difficult. It is also dangerous. Eighteen astronauts
and cosmonauts have died in flights organised by the American and Soviet
space programmes—and three others were killed in a fire during a
rehearsal on the ground. Numerous unmanned rockets have gone wrong as
well. Last week the lesson was hammered home again, on two separate
occasions.
On October 28th an uncrewed Antares rocket operated by Orbital
Sciences, a company contracted by NASA to fly supplies to the
International Space Station (ISS), blew itself up shortly after
launching from a pad in Virginia. The explosion rattled windows in a
town 11km (7 miles) away, but, fortunately, there were no casualties.
Three days later VSS Enterprise, a spaceplane
owned by Virgin Galactic, a firm that hopes to provide wealthy
thrill-seekers with flights to the edge of space, crashed during a test
flight over the Mojave desert (see picture). This time, the toll was
higher: one pilot was killed; the other survived but was badly hurt.
Crashes and explosions are not uncommon, especially with new rockets.
The accidents were unrelated. That both happened in the same week is
nothing more than an unfortunate coincidence. But it is, nevertheless,
an unwelcome blow for enthusiasts of the “New Space” industry, which
aims to use private companies and the discipline of fixed-price
contracts to cut the cost of getting into space.
With investigators still sifting through the wreckage and analysing
flight logs, it is too early to say what caused either crash. But
Orbital Sciences has indicated that the fault may lie with the engines
on its Antares rockets. They are half a century old, having been built
in the Soviet Union in the 1960s for use with the N1, an enormous rocket
that itself suffered four failures, including one launch-pad explosion,
before being abandoned. After the end of the cold war, a cache of the
engines was discovered sitting in a warehouse. Two such engines, after
refurbishment in America, are bolted to the bottom of every one of
Orbital Science’s Antares rockets. The firm had been planning to fit
more modern Russian engines to future versions. It is now likely to make
the switch sooner.
As for Virgin Galactic, armchair crash investigators had, to the
annoyance of Sir Richard Branson, the firm’s billionaire owner, also
talked up the possibility of an engine failure, especially since the
firm had recently altered the fuel mix burned by the spaceplane’s
rocket. But officials from America’s National Transportation Safety
Board (NTSB), which is investigating the crash, announced on November
2nd that they had found the fuel containers and the rocket intact.
The leading theory now is that the spaceplane broke apart under
aerodynamic stress. Virgin’s craft can fly in two configurations: a
low-drag arrangement when climbing into space, and a high-drag one used
to lose speed while descending. According to the NTSB, the high-drag
mode seems to have been engaged while the engine was still firing. If
that is correct, then the resulting forces could have caused the craft
to break up.
Orbital Sciences’s accident is embarrassing, but unlikely to harm it
too much. The firm, which was founded in 1982, has only a toe in the New
Space industry. Besides the Antares, it makes small satellites,
launches a variety of other rockets, and has contracts with the American
armed forces.
If anything, the accident is more embarrassing for NASA, which relies
on the private sector for launches more heavily than it did in its
glory days—often in the face of complaints in Congress. It has a $1.9
billion contract with Orbital to provide eight resupply trips to the ISS
(the failed launch was to have been the third). But any congressional
complaints are likely to be minimal. Partly, that is because, as a big,
established firm, Orbital has friends on Capitol Hill. And partly it is
because the accident will not seriously inconvenience the astronauts
aboard the station.
Even if the investigation unearths a fundamental problem with
Antares’s design, NASA has a similar contract with SpaceX, an upstart
rocketry firm founded by Elon Musk, an internet tycoon. SpaceX has
already completed four missions out of a planned 12. The next is
scheduled to launch in December. Ironically, Orbital’s accident may put
extra pressure on SpaceX. If its flight should fail too, Congress may
reasonably start complaining.
It is for Virgin Galactic that things look trickiest. The firm has no
government contracts. It is entirely reliant on investors and ticket
sales for cash. Those tickets cost $250,000 each and around 700 people
have put down deposits. The firm cannot collect the balance of the
money, though, until commercial flights begin. Its programme is already
behind schedule. Such flights were once due to start in 2008. Following
the change of rocket fuel, Virgin had hoped to begin flying paying
passengers next year. That now looks impossible. And the crash must make
many ticket holders wonder whether they really want to go. One who has
made his views known publicly, Wilson da Silva, an Australian science
journalist, still intends to fly. But around 20 others, the firm says,
have asked for refunds.
Although Virgin is aiming only to take passengers to the edge of
space (defined, somewhat arbitrarily, as beginning at 100km above the
Earth’s surface), and not into full-blown orbit, its technology is, in
many ways, trickier than the stuff operated by Orbital Sciences.
Compared with spaceplanes, conventional rockets are reasonably well
understood.
As George Whitesides, Virgin Galactic’s chief executive, pointed out
in an interview that took place before the crash, there have been around
100 space-launch vehicles in history, but only a handful of
rocketplanes, of which only two (the Space Shuttle and the X-15) have
flown in space with anyone on board. New technology is always tricky to
master; new rocket technology can be some of the trickiest of all.
Tagged as: Incident
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