NASA wants to send a manned mission to Venus. Cool

A man photographs the transit of Venus across the sun. Image: Getty.

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.

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).

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.

Venus was once an Earth twin. Image: NASA.

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

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.

As 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 (approximately 1.4 times greater), which can be used to generate power.

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 per cent carbon dioxide, about 3 per cent 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 per cent 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.

Life on Venus?

The surface of Venus has been mapped from orbit by radar on the US Magellan mission. However, only a few locations on the surface have ever been visited, by the series of Venera missions of Soviet probes in the late 1970s. These probes returned the first – and so far only – images of the Venusian surface. Certainly surface conditions seem utterly inhospitable to any kind of life.

Venus as seen by Magellan. Image: NASA.

The upper atmosphere is a different story however. Certain kinds of extremophile organisms already exist on Earth which could withstand the conditions in the atmosphere at the altitude at which HAVOC would fly. Species such as Acidianus infernus can be found in highly acidic volcanic lakes in Iceland and Italy. Airborne microbes have also been found to exist in Earth’s clouds. None of this proves that life exists in the Venusian atmosphere, but it is a possibility that could be investigated by a mission like HAVOC.

The current climatic conditions and composition of the atmosphere are the result of a runaway greenhouse effect (an extreme greenhouse effect that cannot be reversed), which transformed the planet from a hospitable Earth-like “twin” world in its early history. While we do not currently expect Earth to undergo a similarly extreme scenario, it does demonstrate that dramatic changes to a planetary climate can happen when certain physical conditions arise.


By testing our current climate models using the extremes seen on Venus we can more accurately determine how various climate forcing effects can lead to dramatic changes. Venus therefore provides us with a means to test the extremes of our current climate modelling, with all the inherent implications for the ecological health of our own planet.

We still know relatively little about Venus, despite it being our nearest planetary neighbour. Ultimately, learning how two very similar planets can have such different pasts will help us understand the evolution of the solar system and perhaps even that of other star systems.

The Conversation

Gareth Dorrian, Post Doctoral Research Associate in Space Science, Nottingham Trent University and Ian Whittaker, Lecturer, Nottingham Trent University.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

 
 
 
 

Covid-19 is highlighting cities' unequal access to green space

In the UK, Londoners are most likely to rely on their local park for green space, and have the best access to parks. (Leon Neal/Getty Images)

As coronavirus lockdowns ease, people are flooding back to parks – but not everyone has easy access to green space in their city.

Statistics from Google show that park attendance in countries across the globe has shot up as people have been allowed to move around their cities again.

This is especially true in urban areas, where densely populated neighbourhoods limit the size of private green space – meaning residents have to go to the park to get in touch with nature. Readers from England can use our interactive tool below to find out how much green space people have access to in their area, and how it compares to the rest of the country.

 

Prime Minister Boris Johnson’s announcement Monday that people are allowed to mingle in parks and gardens with groups of up to six people was partially following what people were doing already.

Data from mobile phones show people have been returning to parks across the UK, and also across Europe, as weather improves and lockdown eases.

People have been returning to parks across the world

Stay-at-home requirements were eased in Italy on 4 May, which led to a flood of people returning to parks.

France eased restrictions on 1 May, and the UK eased up slightly on 13 May, allowing people to sit down in public places so long as they remain socially distanced.

Other countries have seen park attendance rise without major easing of lockdown – including Canada, Spain, and the US (although states there have individual rules and some have eased restrictions).

In some countries, people never really stopped going to parks.

Authorities in the Netherlands and Germany were not as strict as other countries about their citizens visiting local parks during lockdown, while Sweden has famously been avoiding placing many restrictions on people’s daily lives.


There is a growing body of evidence to suggest that access to green space has major benefits for public health.

A recent study by researchers at the University of Exeter found that spending time in the garden is linked to similar benefits for health and wellbeing as living in wealthy areas.

People with access to a private garden also had higher psychological wellbeing, and those with an outdoor space such as a yard were more likely to meet physical activity guidelines than those without access to outdoor space. 

Separate UK research has found that living with a regular view of a green space provides health benefits worth £300 per person per year.

Access is not shared equally, however, which has important implications for equality under lockdown, and the spread of disease.

Statistics from the UK show that one in eight households has no garden, making access to parks more important.

There is a geographic inequality here. Londoners, who have the least access to private gardens, are most likely to rely on their local park for green space, and have the best access to parks. 

However the high population in the capital means that on the whole, green space per person is lower – an issue for people living in densely populated cities everywhere.

There is also an occupational inequality.

Those on low pay – including in what are statistically classed as “semi-skilled” and “unskilled” manual occupations, casual workers and those who are unemployed – are almost three times as likely as those in managerial, administrative, professional occupations to be without a garden, meaning they rely more heavily on their local park.

Britain’s parks and fields are also at significant risk of development, according to new research by the Fields in Trust charity, which shows the number of people living further than a 10-minute walk from a public park rising by 5% over the next five years. That loss of green spaces is likely to impact disadvantaged communities the most, the researchers say.

This is borne out by looking at the parts of the country that have private gardens.

The least deprived areas have the largest gardens

Though the relationship is not crystal clear, it shows at the top end: Those living in the least deprived areas have the largest private green space.

Although the risk of catching coronavirus is lower outdoors, spending time in parks among other people is undoubtedly more risky when it comes to transmitting or catching the virus than spending time in your own outdoor space. 

Access to green space is therefore another example – along with the ability to work from home and death rates – of how the burden of the pandemic has not been equally shouldered by all.

Michael Goodier is a data reporter at New Statesman Media Group, and Josh Rayman is a graphics and data visualisation developer at New Statesman Media Group.