Stratos!
Posted: Thu Oct 18, 2018 4:16 am
Popular science fiction of the early 20th century depicted Venus as some
kind of wonderland of pleasantly warm temperatures, forests, swamps and
even dinosaurs. In 1950, the Hayden Planetarium at the American Natural
History Museum were soliciting reservations for the first space tourism
mission, well before the modern era of Blue Origins, SpaceX and Virgin
Galactic. All you had to do was supply your address and tick the box for
your preferred destination, which included Venus.
57841 Today, Venus is unlikely to be a dream destination for aspiring space
tourists. As revealed by numerous missions in the last few decades,
rather than being a paradise, the planet is a hellish world of infernal
temperatures, a corrosive toxic atmosphere and crushing pressures at
the surface. Despite this, NASA is currently working on a conceptual
manned mission to Venus, named the High Altitude Venus Operational
Concept – (HAVOC).
57842 But how is such a mission even possible? Temperatures on the planet's
surface (about 460°C) are in fact hotter than Mercury, even though
Venus is roughly double the distance from the sun. This is higher
than the melting point of many metals including bismuth and lead,
which may even fall as "snow" onto the higher mountain peaks. The
surface is a barren rocky landscape consisting of vast plains of
basaltic rock dotted with volcanic features, and several continent-
scale mountainous regions.
It is also geologically young, having undergone catastrophic
resurfacing events. Such extreme events are caused by the build up
of heat below the surface, eventually causing it to melt, release
heat and re-solidify. Certainly a scary prospect for any visitors.
Hovering in the atmosphere...
57843 Luckily, the idea behind NASA's new mission is not to land people
on the inhospitable surface, but to use the dense atmosphere as a
base for exploration. No actual date for a HAVOC type mission has
been publicly announced yet. This mission is a long term plan and
will rely on small test missions to be successful first. Such a
mission is actually possible, right now, with current technology.
The plan is to use airships which can stay aloft in the upper
atmosphere for extended periods of time.
Is surprising as it may seem, the upper atmosphere of Venus is
the most Earth-like location in the solar system. Between altitudes
of 50km and 60km, the pressure and temperature can be compared to
regions of the Earth's lower atmosphere. The atmospheric pressure
in the Venusian atmosphere at 55km is about half that of the pressure
at sea level on Earth. In fact you would be fine without a pressure
suit, as this is roughly equivalent to the air pressure you would
encounter at the summit of Mount Kilimanjaro. Nor would you need
to insulate yourself as the temperature here ranges between 20°C
and 30°C.
The atmosphere above this altitude is also dense enough to protect
astronauts from ionising radiation from space. The closer proximity
of the sun provides an even greater abundance of available solar
radiation than on Earth, which can be used to generate power
(approximately 1.4 times greater).
The conceptual airship would float around the planet, being blown
by the wind. It could, usefully, be filled with a breathable gas
mixture such as oxygen and nitrogen, providing buoyancy. This is
possible because breathable air is less dense than the Venusian
atmosphere and, as result, would be a lifting gas. The Venusian
atmosphere is comprised of 97% carbon dioxide, about 3% nitrogen
and trace amounts of other gases. It famously contains a sprinkling
of sulphuric acid which forms dense clouds and is a major contributor
to its visible brightness when viewed from Earth. In fact the planet
reflects some 75% of the light that falls onto it from the sun. This
highly reflective cloud layer exists between 45km and 65km, with a haze
of sulphuric acid droplets underneath down to about 30km. As such, an
airship design would need to be resistant to the corrosive effect of
this acid.
Luckily we already have the technology required to overcome the problem
of acidity. Several commercially available materials, including teflon
and a number of plastics, have a high acidic resistance and could be used
for the outer envelope of the airship. Considering all these factors,
conceivably you could go for a walk on a platform outside the airship,
carrying only your air supply and wearing a chemical hazard suit.
kind of wonderland of pleasantly warm temperatures, forests, swamps and
even dinosaurs. In 1950, the Hayden Planetarium at the American Natural
History Museum were soliciting reservations for the first space tourism
mission, well before the modern era of Blue Origins, SpaceX and Virgin
Galactic. All you had to do was supply your address and tick the box for
your preferred destination, which included Venus.
57841 Today, Venus is unlikely to be a dream destination for aspiring space
tourists. As revealed by numerous missions in the last few decades,
rather than being a paradise, the planet is a hellish world of infernal
temperatures, a corrosive toxic atmosphere and crushing pressures at
the surface. Despite this, NASA is currently working on a conceptual
manned mission to Venus, named the High Altitude Venus Operational
Concept – (HAVOC).
57842 But how is such a mission even possible? Temperatures on the planet's
surface (about 460°C) are in fact hotter than Mercury, even though
Venus is roughly double the distance from the sun. This is higher
than the melting point of many metals including bismuth and lead,
which may even fall as "snow" onto the higher mountain peaks. The
surface is a barren rocky landscape consisting of vast plains of
basaltic rock dotted with volcanic features, and several continent-
scale mountainous regions.
It is also geologically young, having undergone catastrophic
resurfacing events. Such extreme events are caused by the build up
of heat below the surface, eventually causing it to melt, release
heat and re-solidify. Certainly a scary prospect for any visitors.
Hovering in the atmosphere...
57843 Luckily, the idea behind NASA's new mission is not to land people
on the inhospitable surface, but to use the dense atmosphere as a
base for exploration. No actual date for a HAVOC type mission has
been publicly announced yet. This mission is a long term plan and
will rely on small test missions to be successful first. Such a
mission is actually possible, right now, with current technology.
The plan is to use airships which can stay aloft in the upper
atmosphere for extended periods of time.
Is surprising as it may seem, the upper atmosphere of Venus is
the most Earth-like location in the solar system. Between altitudes
of 50km and 60km, the pressure and temperature can be compared to
regions of the Earth's lower atmosphere. The atmospheric pressure
in the Venusian atmosphere at 55km is about half that of the pressure
at sea level on Earth. In fact you would be fine without a pressure
suit, as this is roughly equivalent to the air pressure you would
encounter at the summit of Mount Kilimanjaro. Nor would you need
to insulate yourself as the temperature here ranges between 20°C
and 30°C.
The atmosphere above this altitude is also dense enough to protect
astronauts from ionising radiation from space. The closer proximity
of the sun provides an even greater abundance of available solar
radiation than on Earth, which can be used to generate power
(approximately 1.4 times greater).
The conceptual airship would float around the planet, being blown
by the wind. It could, usefully, be filled with a breathable gas
mixture such as oxygen and nitrogen, providing buoyancy. This is
possible because breathable air is less dense than the Venusian
atmosphere and, as result, would be a lifting gas. The Venusian
atmosphere is comprised of 97% carbon dioxide, about 3% nitrogen
and trace amounts of other gases. It famously contains a sprinkling
of sulphuric acid which forms dense clouds and is a major contributor
to its visible brightness when viewed from Earth. In fact the planet
reflects some 75% of the light that falls onto it from the sun. This
highly reflective cloud layer exists between 45km and 65km, with a haze
of sulphuric acid droplets underneath down to about 30km. As such, an
airship design would need to be resistant to the corrosive effect of
this acid.
Luckily we already have the technology required to overcome the problem
of acidity. Several commercially available materials, including teflon
and a number of plastics, have a high acidic resistance and could be used
for the outer envelope of the airship. Considering all these factors,
conceivably you could go for a walk on a platform outside the airship,
carrying only your air supply and wearing a chemical hazard suit.