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| Credit: NASA |
After more than 20
years of neglect, the planet Venus is once more drawing NASA's eye for
ambitious new missions.
A Venusian dream
expedition for some scientists would include nothing short of an exploration
flotilla ? a ground robot, planetary airplane and orbiting manned spacecraft.
The potential mission to Venus could investigate its surface from up-close for
the first time in several decades, a NASA scientist said. [Photos: The
surface of Venus.]
"Recently there
has been a renaissance in looking at proposals to study Venus," researcher
Geoffrey A. Landis at NASA's John Glenn Research Center in Ohio told SPACE.com.
"One very good reason is that there has been a renewed interest in study
of the atmospheres and climates of planets, and ? being the planet that is most
like the Earth in size ? learning more about the atmosphere
of Venus may help us learn more about the atmosphere (and climate) of the
Earth."
NASA is expected to
hold its first meeting to discuss potential
new Venus missions in early August, Landis said.
There hasn't been a
dedicated U.S. mission sent to Venus since the Magellan probe in 1989, but that
doesn't mean the planet has not seen its share of visitors.
The European Space
Agency currently has an orbiter called Venus Express circling Venus, and Japan
launched its spacecraft Akatsuki (Japanese for "Dawn") toward the
planet in May. Several NASA probes have flown by Venus in the last 20 years,
but only as a pit stop on the way to other planets in the solar system.
Venus also saw
visiting probe from the United States and Russia the 1960s, '70s and '80s, even
some landings on the Venusian surface. But those probes were extremely
short-lived because of the crushing pressure and extreme heat of Venus'
atmosphere.
Bring humans to Venus
And after two decades
of technological advancements, an extended robotic landing on Venus is now
possible, Landis said. Today's high-temperature electronics, power and cooling
systems could allow a ground probe to explore for longer than two hours.
The last spacecraft
to land on Venus was Russia's Venera 14, which touched down on Venus in March
1982 and survived for 57 minutes ? nearly twice its expected design lifetime,
according to NASA records.
But humans from Earth
will still likely not step foot on the hellish
Venus surface, where the temperature is hotter than most ovens ? about 870
degrees Fahrenheit (465 degrees Celsius) ? and the atmospheric pressure is
about 90 times that of the Earth.
"Venus is so
hostile that we're not likely to land humans on it anytime in the foreseeable
future," Landis said.
But scientists still
have a technique up their sleeves that could allow humans to explore Venus
virtually via "teleoperation" of a remote-controlled probe from
inside an orbiting spaceship.
By connecting
astronauts to real-time visual and tactile data streamed by the robot, the
system can allow astronauts to interact with the Venusian environment without
the time-lag of controlling a robot from Earth, Landis said.
There are still some
challenges for astronauts even if they don't set foot on Venus.
Venus explorers
orbiting the planet would still need radiation and heat protection from the
effects of orbiting a little closer to the sun. In addition, a source of
artificial gravity may be necessary to counteract the loss of bone mass
expected for astronauts living for long periods in weightlessness.
"Fortunately,
we are learning a lot about long-duration habitation in space from the
International Space Station, and by the time we're ready to send this mission,
most of the difficult questions will be better understood, and many of the
technologies chosen," Landis said.
Dusting off a
solar plane
Another
possible component of the mission may involve resurrecting a solar-powered
airplane concept to traverse the planet's thick and "tremendously
exciting" atmosphere, Landis said.
Since
Venus resembles the surface of Earth when it first formed, the thick carbon
dioxide covering Venus could tell us a lot about our own planet's evolution, he
added. A compact plane that could unfold during entry could be a vital probe to
record conditions from inside Venus' atmosphere.
The
project was cancelled years ago, but not before engineers completed enough work
to be confident it would work in the atmosphere of another world.
Initially conceived
for Mars aerial exploration, the solar-powered planetary airplane would work
especially well for Venus because the planet takes 243 Earth days to complete
a single Venusian day.
"Venus rotates
so slowly that we could essentially fly forever because the airplane can fly
faster than the speed it rotates and then stay in sunlight all the time. It
never runs out of fuel, or energy," Landis said.
Venus' long days do
come with a price: high winds that would challenge the plane's flight limits.
In theory, the
plane's speed would be a mere 10 mph (16 kph). But once immersed in the
atmosphere of Venus, the aircraft would have to battle wind speeds of around
200 mph (321 kph) in order to keep in the sun.
So the speed required
to compensate would be pretty high for solar airplanes but slower than a
typical airliner, Landis said.
There's an
aerodynamic challenge, too. In the earlier studies, engineers had to work hard
to pack as many solar panels as possible onto wings yet still minimize drag.
"Turns out the
interesting thing about the solar plane is that the bigger you make the wing
the more power you get," Landis said.
- See
Beneath the Clouds of Venus, Venus
Postcards
- Video:
Venus Robotic Mission Animations
- Oceans
on Venus Might Have Been Habitable
