Nasa scientists were celebrating last night as their latest mission – the Mars Atmosphere and Volatile Evolution probe, or Maven for short – successfully entered into a stable orbit around the fourth planet from the Sun.
Maven was launched from Cape Canaveral on 18 November 2013, meaning yesterday’s arrivel marked the end of a journey of almost exactly ten months. For the next six weeks the craft will run a series of tests to make sure all of its instruments are working fine, and then begins the main mission: for one (Earth) year, Maven will study the top layers of Mars’ atmosphere and ionosphere. In this sense it’s similar to some of the climate satellites in orbit around the Earth, but the key objective with Maven is to answer a specific question: where the hell did all the air go?
When the planets first formed, we’re pretty sure that Mars had an atmosphere comparable to the Earth’s – that is, it was dense enough for liquid water to run freely across the surface, in oceans and rivers, carving out canyons and shorelines that we can still see today. That was millions of years ago, however, and today Mars is a snowball. There’s plenty of water ice at the poles, but as long as the atmosphere is so weak – at less than one per cent of the density of Earth’s – there’s no chance of those ancient bodies of water being reborn. (Recent pictures of dark “streaks” down the sides of some gullies may be evidence of brief summer flows of salty water, but the debate over whether this is a) even a liquid, and b) if a liquid, water, is ongoing.)
Maven’s going to do something quite exciting when its main mission begins – its orbit is going to be a huge ellipse, with the furthest point from the Martian surface being 6,300km and the closest at 150km. At five points over the course of the primary mission, Maven will be made to dip even lower towards the surface of the planet, as low as 125km, where it will take as many measurements of the upper atmosphere at possible. It’ll try to figure out how fast Mars is losing its atmosphere (it’s mostly carbon dioxide at this point) to space, stripped away by the solar wind, and scientists can then extrapolate back from those readings to figure out how long ago it was since it was relatively Earth-like. Our atmosphere is protected by our planet’s magnetic, molten iron core, which Mars doesn’t have, and nor does it have active volcanoes to replace the gases it loses. When Mars lost these traits – or whether it ever had them – is one of the more fundamental scientific questions regarding the Red Planet.
Much of our obsession with exploring Mars is related to the idea that it used to be like Earth, and therefore there’s maybe life there (dead and fossilised, of course, but still). There’s even the idea that microbial life originally evolved on Mars while the young Earth was undergoing a tumultuous combination of meteorites and volcanoes, and that it was then carried by an asteroid inwards to seed the third planet while the fourth froze. The chance of proving this is extraodinary slim, but the chance of proving it was possible is a far bit higher. At the very least, Mars seems to be the default choice for a future space colony, and knowing as much as possible about our future second home seems a wise scientific investment.
This partly explains why Mars is currently so busy, as, including Maven, there are now six active missions there. There are the two robot rovers Curiosity and Opportunity, and then there are the three other orbiters: Mars Odyssey (in orbit since 2001, studying surface ice and acting as a communications relay for other missions), Mars Express (2003, mapping the surface and studying the atmosphere, brother of the failed Beagle 2 lander) and the Mars Reconnaissance Orbiter (a mapping satellite, and a main source for Google Mars). And, remarkably, in two days we can expect another probe to arrive in Martian orbit – Mangalyaan, the first Mars mission by the state space agency of India, the India Space Research Organisation (Isro).
Mission controllers in Bangalore are currently getting Mangalyaan ready to slow down, having successfully tested its thrusters and other systems, and when it arrives it will take some pictures and analyse the gassy molecules floating around on the edge of the atmosphere. However, the mission is conceived as a study in interplanetary travel more than anything, as Isro will be only the fourth space agency (after Nasa, Roscosmos and the ESA) to make it to Mars. This is especially impressive considering that funding for the $25m probe was only approved in August 2012, after initial planning began in 2010. Assuming it’s successful, Isro expects to send a more significant, scientifically-capable follow-up within the next five years.
In a way, it’s possible to see the near-simultaneous arrivals of Maven and Mangalyaan at Mars as symbolic of wider changes happening in the space industry. The current international system of cooperation between the major space agencies of the world, as best seen in the International Space Station, is breaking down somewhat under the realities of geopolitical competition. This isn’t to say that agencies still aren’t helping each other – Mangalyaan wouldn’t have got as far as it did if it weren’t for Nasa providing help with communications and navigation – but it’s becoming easier for agencies like Isro to think of doing things alone. Space is exciting, and something to be proud of, and as an emerging global power India has every right to develop its own capability. (As does China, which has rapidly come to surpass Russia as the second-most capable space-faring nation.)
Meanwhile, Nasa has contracted private companies SpaceX and Boeing to create the next generation of vessel for ferrying astronauts to and from the ISS so it isn’t entirely reliant on Russia-owned and -made Soyuz craft; and Russia has said that when the current ISS mission expires in 2020 it wants to break off its segments and build its own new station, by itself. Japan and the European Union are also making impressive progress, while other large nations like Brazil will surely join the party within the next few decades, too. We shouldn’t be surprised that America’s two-decade dominance of space is being challenged at the same time as a bunch of other nations are fancying themselves equally legitimate great powers in the political arena. It’s great for international prestige, after all, and the technological and scientific benefits aren’t to be ignored.
Interestingly, both Mangalyaan and Maven were threatened by the US federal government’s shutdown in 2013. With Maven, two days of lost work almost threatened a delay of 14 months due to a missed launch window, and Nasa had to request emergency funding simply because Maven is so crucial to keeping communications open with other missions on Mars like Curiosity. Mangalyaan, which relies on communications help from Nasa, also had its launch threatened. It kind of reflects how Nasa isn’t the major national obsession it once was in America – and how nations who rely on the US for help, have an incentive not to be threatened by domestic carelessness.