You could say that Venus is the forgotten world of the inner
solar system. Outshined, figuratively, by her superficially more interesting
brother Mars, Venus holds both the potential for microbial life and the
eventual potential of terraforming and human colonization. And, as I pointed
out in my video "Colonizing and Terraforming Venus" it has advantages
that Mars does not. But that forgotten status may soon change if a new space
probe targeting the planet is approved.
Its name is Venera D after the venerable soviet-era Russian
probes and landers of the 1970's and 80's that brought us the first pictures
from the surface of Venus. And while Venus has not been a high priority for
NASA, they have their eyes on Mars, RosCosmos has never lost interest in Venus
and hopefully will collaborate with NASA on this mission and once again visit
earth's sister world launching in 2025.
The mission, as planned right now, would include an orbiter
designed to study both the atmosphere and surface in detail from orbit using
powerful radar, but also to deploy a robust lander on the surface. And it would
need to be robust, the rough conditions of the surface have only allowed for
previous probes to survive for less than a few hours.
Possible additions to the mission include a drone designed
to cruise the clouds of Venus, a second micro orbiter for studying Venus'
magnetosphere, such as it is given that it basically borrows one from the sun,
and even a high altitude balloon.
There are many reasons to study Venus' atmosphere directly.
One reason is that for some unknown reason the atmosphere rotates significantly
faster than the planet does. This super-rotation was discovered by studying an
even stranger phenomenon. Within Venus' atmosphere there are dark streaks that
display some strange properties. After knowing about the streaks since the
1960's to this day we have no idea what they are or why they are there.
The streaks are odd. They should have long ago mixed in with
the atmosphere and disappeared. They have not. And, even stranger, they absorb
ultraviolet light which somewhat restricts what they could be made of. We know
nothing about their composition, but one possibility is that they are made up
of iron chloride. Think of it as a kind of atmospheric ice, sort of like ice
crystals in earth's atmosphere but in the much hotter conditions of Venus.
The problem with that theory is that the iron chloride would
need to be coming from the surface. The trouble is there doesn't appear to be a
way for that to happen, Venus' winds in the lower dense atmosphere are too
weak. It could also be some other chemical dissolved or partially dissolved in
Venus' atmosphere, but again, how it hasn't mixed in with the rest of the
atmosphere is unknown. Given that the explanations thus far aren't very good,
it's worth considering another possibility. Microbial life.
Microbes living in an atmosphere is nothing new. We find tons
of them in earth's atmosphere. More, while Venus is extraordinarily hot, one
area of it isn't. There is a region about 30 to 40 miles above the surface of
Venus where the temperature and atmospheric pressure is earth-like. This also
seems to be the location of the dark streaks. Intriguing indeed. And, oddly
enough earlier Venera missions did detect some kind of elongated particles in
the atmosphere that were about the right size for a bacterium.
But there's a huge hurdle. Venus' atmosphere is loaded with
sulfuric acid. This is nasty stuff that life would have a hard time with. That
is, unarmored life. Within Venus' atmosphere interesting molecules have been
found that are called S8 molecules. Made up of a ring of sulfur atoms, these
molecules are immune to the effects of sulfuric acid. If Venera's particles are
indeed bacteria, they could have incorporated S8 during their evolution and
essentially armored themselves.
Even more interesting is the fact that S8 does absorb
ultraviolet light, meaning that it could be the culprit for the streaks. It's
even been suggested that the presence of the S8 could be a direct result of
microbial life. Because of all of this, an investigation of the potential for
life in Venus' atmosphere is being looked at as one of the Venera D mission objectives.
Key to this however would be the drone. Balloons are hard to
maneuver, so to get to the layer where the bacteria might be you would need a
controllable aircraft. This is not so far fetched as you might think, it should
be easily possible to build a solar powered UAV filled with hydrogen as a sort
of hybrid balloon/airplane, something like a blimp.
Northrop Grumman has a concept for just such a vehicle.
Known as VAMP or the Venus Atmospheric Maneuverable Platform, it would be huge with a 180 foot wingspan and a mission
length of an entire year without ever landing. It would deploy from the orbiter
and fall like a leaf through Venus' atmosphere until reaching the optimum
altitude for the mission and then essentially fly anywhere in the atmosphere we
need to go with a 100 lb capacity for scientific instruments.
A final plan for the mission will be submitted at the end of
this month. An answer whether NASA and Roscosmos wish to accept the mission and
collaborate will come at the end of 2017 or sometime in 2018.
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