The test will last 2 minutes and will cost 350 million dollars
Like for the amazing Concorde, the supersonic airliner that was
retired in 2003, 34 years from its first flight and after 27 years of
uninterrupted service, retirement is also raising its head for the
even more famous Space Shuttle, the spacecraft par excellence that
marked the era of orbital flights. The shuttle’s successor will take
off for the first time next summer, in July, from NASA’s Kennedy Space
Center in Florida. The American space agency has stated that the Ares
I-X, a prototype of the new generation of spacecraft, will make its
first flight at just over 40 kilometers above the Earth, in a test
that will last two minutes overall, but which will cost NASA 350
million dollars. The test should perfect the first stage of the
vehicle and the phase of re-entry to the atmosphere using parachutes.
With this launch, American scientists hope to discover whether the
rocket is in effect stable and safe during launch, the main worry with
this craft, so that it can be used in future for manned flights. The
first astronauts will use the Ares for a space flight no earlier than
2015. NASA works hard on future generations of space rockets but news
of the first launch is a clear signal of its will to accelerate the
program in light of the cuts on all “inefficient” expenditures
promised by Barack Obama’s new administration . NASA will probably
keep its shuttles in operation until the debut of the new American
manned carrier in 2015 to avoid a 5-year loss of launch autonomy, but
doing so could cost 11 billion dollars. Such a choice would involve
high risks for the astronauts and would damage (for technical and
economic reasons) the Constellation program for a return to the Moon
in 2020.
There is much talk about extending the operation of space shuttles
beyond 2010, especially as the loss of launch autonomy would result in
American dependency on Russian Soyuz vehicles for at least five years
in order to send American astronauts to the international space
station. Regarding the Ares 1 vehicle, the successor to the shuttle
for piloted flights, even chiefs of NASA and Lockheed Martin, who make
the 1st stage, recognize that problems exist, and suggest that a final
decision has yet to be made on its future. At the same time, the
vehicle, which ought to guarantee a leap in quality for the safety of
US astronauts, is overshadowed by increasing doubts of a political and
economic nature relating to delays in testing, increase in costs and
the direction that the newlyelected president Barack Obama wishes to
impose on the
American space program. «We have a lot of data on the performance of
the solid stage, thanks to the shuttles - we were told by Herbert
Shivers, NASA Deputy Director of Safety and Mission Assurance at the
Marshall Space Flight Center - and a test flight will give us a better
understanding of its performance in this new design. We will make the
decisions on Ares 1 afterwards. We are certainly not going to put
people on board a vehicle that we don’t know inside out». A statement
that represents a significant change compared with the solid position
that NASA and its director Michael Griffin appeared to have regarding
the Ares 1 vehicle, presented as a jewel of economic efficiency (the
design is based on reuse of technologies already in use on the shuttle
and the Saturn lunar spacecraft, like the first solid stage derived
from the boosters of the space shuttle) and safety (according to the
NASA axiom: technology already tested on approximately 240 boosters =
safe technology). Therefore, no longer an irrevocable choice: «At the
moment we are working on Ares 1 and, based on what we learn, we will
make the decision», Shivers repeated.
Besides, because of its shape, thin and long at the bottom, and
wide and heavy at the top (earning it the nickname “the stick” within
NASA itself), many believe that Ares 1 will have serious order check
problems. «It’s a problem of design and dynamics that the engineers
are examining», confirmed Michael Saemisch, head of the “reusable
space transport systems” sector of Lockheed Martin. «The solid fuel
engines - he explained - have, on the other hand, demonstrated great
reliability in the shuttle missions, and besides, solid fuel engines
are simpler and therefore safer than liquid fuel engines, which
require a lot of valves and moving parts. That’s why NASA has gone for
this type of engine for Ares 1». «Certainly - he continued - vibration
is a big problem that is still to be resolved, and various solutions
are being studied both for Ares and for the Orion capsule. But I would
not say that Ares 1 is not safe. We are becoming more confident as we
go on». However, we asked, is it not the case that the solid fuel
engine also has the disadvantage that it cannot be switched off if the
launch is aborted ?… «This is true - said Saemish - and we are working
on an emergency system which, in the event of problems, will remove
the capsule and the astronauts from the launch vehicle. The problem is
that at the moment we have excessive acceleration, which could not be
tolerated by the astronauts». Although this is news, which did not
even emerge when tests on the rescue tower were carried out at the end
of November, it is however clear that Ares 1 would be a real space
“shaker” for the astronauts in the Orion capsule on top of it. The
solid fuel engines in fact generate strong vibroacoustic oscillations,
which certainly do no good to the rocket, the electronics, the
cryogenic components of the second stage and, not least, to the
astronauts. In fact, if Ares ever sees the light of day, the
astronauts will be subjected to vibrations of up to 0.5 G, which would
make it impossible - for example - to read the instruments (it would
be like trying to read the data on your GPS navigator while driving
along a road with loose cobblestones). To reduce these vibrations to
at least 0.25G (acceptable for reading the instrumentation) two routes
can be taken: an active route, intervening in the design of the first
stage, and in this direction new configurations of the interstages and
the engine have been proposed, amongst other things; and a passive
route, introducing shockabsorbers, with an increase in weight, which
will inevitably impact the performance of the rocket, probably making
it unusable for the lunar missions for which it was also designed. We
should remember that the choice to use solid fuel boosters also
involves greater accelerations with a greater G load for those on
board. In addition, their power cannot be modulated in order to
optimize the flight stages (or, more precisely, it can be modulated,
but only beforehand with variations in the mix, and only to a relative
extent).
Thirdly, and this is one of the major problems in the case of a manned
vehicle, the solid fuel propulsor cannot be switched off in the event
of an emergency (this makes the stages from ignition of the shuttle up
to the release of the boosters risky, for example); and this gives
rise to the above-mentioned problems also in the creation of a rescue
tower, which would have to work by accelerating from a rocket that is
itself in full acceleration. Barack Obama’s arrival at the White House
also has an impact on the fate of Ares 1., In a document from last
August Obama embraced the plan to return to the Moon in 2020 and
implied the necessity to accelerate the development of new manned
vehicles to replace the shuttle, but without ever mentioning either
Ares or the Orion capsule. The transition commission for NASA has, on
the other hand, mentioned the possibility of making the existing Delta
IV and Atlas V manned. Since the Government Accountability Office (GAO),
a bipartisan Congress group, in a document issued on November 6,
identified the retirement of the shuttle as one of the 13 most urgent
issues to be resolved in the first year of the Obama presidency, it is
likely that we will not have to wait very long to discover the future
of Ares 1, of the shuttles and of the Constellation program.
Erika Laganà
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