NASA lands nuclear-powered, laser-armed, one-tonne rover on Mars

The Curiosity rover has been travelling for 10 months and made a safe touchdown this morning.

At 6:30am BST, NASA's Curiosity rover touched down on Mars, making it the seventh successful attempt to land a man-made object on the planet, and the largest such object yet.

Following its launch from Cape Canaveral in November last year, the mission has covered the 563 million kilometer distance without concern, but the most dangerous aspect of the trip was always going to be the last seven minutes of the descent to Mars. The Martian atmosphere is thin enough that it isn't capable of slowing objects travelling at interplanetary velocity down enough for them to make a safe landing, while being thick enough that the friction is capable of doing serious damage to an unprotected craft.

Once the rover hit the atmosphere, it had to execute a complicated series of manouvers, first deploying a massive parachute, then rocket thrusters, and then, at the very end, hovering just above the surface and lowering the car-sized rover down on nylon strings. And it had to do all of this without any aid from the control room on Earth, due to the 14 minutes it takes for radio signals from Mars to reach earth. So by the time we heard that the rover had hit the atmosphere, it had actually been sitting on the planet – dead or alive – for seven minutes.

NASA's video explaining the "seven minutes of terror" – unfortunately officially called "EDL", for "entry, descending, landing" – conveys the sheer scale of the challenge:

Now that it has arrived, the rover's first task is to explore Gale crater, its landing site. The crater contains a number of interesting geological features, including what appears to be a 5km high mountain formed out of sedimentary rock, which would make it one of the largest artifacts of running water on Mars.

But that preliminary mission is unlikely to be the rover's only one. NASA's increasingly successful missions to send rovers to Mars have been typified by the flexibility which the mobile design offers. The Pathfinder mission, which deposited a lander (a stationary craft) and a rover (named Sojourner) on Mars in 1997, was intended to last a week to a month, but ended up returning usable data for three. The follow-up rovers, Spirit and Opportunity, landed in 2004 with 90 days of planned experiments. Spirit eventually got stuck in late 2009 and stopped sending signals back to Earth in 2010, while its twin Opportunity is still active, 3,026 days after its mission was supposed to end.

But Curiosity is a different scale of mission – literally. While Sojourner was 65cm long and weighed 10.5kg, and Spirit and Opportunity 1.6m and 180kg, Curiosity is over 3m long and weighs almost a tonne. Rather than being powered by solar panels, which runs the risk of outages during dust storms and the Martian night, it contains a plutonium battery, which generates heat to be turned into electricity. It also has a laser which can burn holes in rocks from up to 7 meters away, in case of attack to analyse the chemical composition of the planet, and sensors which detect visible light, x-rays, neutrons and ultraviolet radiation, all for science. In essence, NASA has landed a nuclear power, laser-armed SUV on Mars for one fifth the cost of the Olympics. Oh, and it tweets.

 

The Mars rover family. Pictured, clockwise from bottom left: models of Sojourner, Spirit/Opportunity, two human males, and Curiosity. Photograph: NASA

Alex Hern is a technology reporter for the Guardian. He was formerly staff writer at the New Statesman. You should follow Alex on Twitter.

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Doing a Radiohead: how to disappear online

The band has performed an online Houdini in advance of its ninth album – but it’s harder than it looks. 

At the beginning of May, the band Radiohead’s web presence – well, its Twitter, Facebook, and website, at least – went offline.

Lead singer Thom Yorke has repeatedly criticised streaming, and the future of online music in general, and it's clear that his opinion fed into this month's decision to reject social media in favour of sending individual cards to the band's fans in the post. 

However, it’s also a clever publicity stunt in the run up to the rumoured release of the band's ninth album, since it plays into a growing paranoia around the lives we live online, and quite how permanent they are. In reality, though, Radiohead has done a pretty terrible job of disappearing from the internet. Its Facebook and Twitter accounts still exist, and widely available caching services actually mean you can still see Radiohead.com if you so wish. 

These are the steps you’d need to take to really disappear from the internet (and never be found).

Delete your acccounts

Radiohead may have deleted its posts on Facebook and Twitter, but its accounts – and, therefore user data – still exist on the sites. If this was a serious move away from an online presence, as opposed to a stunt, you’d want to delete your account entirely.

The site justdelete.me rates sites according to how easy they make it to delete your data. If you only hold accounts with “easy” rated sites, like Airbnb, Goodreads and Google, you’ll be able to delete your account through what justdelete.me calls a “simple process”. JustDelete.me also links you directly to the (sometimes difficult-to-find) account deletion pages.

Failing that, delete what you can

If, however, you’re a member of sites that don’t allow you to delete your account like Blogger, Couchsurfing or Wordpress, you may be stuck with your account for good. However, you should at least be able to delete posts and any biographical information on your profile.

If this bothers you, but you want to create an account with these sites, Justdelete.me also offers a “fake identity generator” which spits out fake names and other details to use in the signup process.

Go to Google

Search results are the hardest thing to erase, especially if they’re on sites which published your details without your permission. However, thanks to the European Commission “Right to be forgotten” ruling in 2014, you can now ask that certain search results be deleted using this online form.  

Ditch your smartphone

Smartphones tend to track your location and communicate with app and web servers constantly. For true privacy, you’d want to either disconnect your phone from all accounts (including iCloud or Google) or else get a basic phone which does not connect to the internet.

Give out your passwords

The artist Mark Farid decided in October 2015 to live without a digital footprint until April 2016, but was aghast when he realised quite how often our data is collected by our devices. As a result, he decided to live without bank accounts, use a phone without internet connectivity, and use an unregistered Oyster.

When I saw him speak at an event just before his off-grid experiment was due to begin, he announced that he would also be handing out the passwords to all his online accounts to the public. The kind of “bad data” which randomly hacked accounts would show would actually make him less traceable than a radio silence – a bit like how words written over other words mask them more than simply erasing them or scribbling on them would.

Accept that it probably won’t work

Even if you managed all this, the likelihood is that some of your daily activities would still leave a trace online. Most jobs require internet activity, if not an internet presence. Bank accounts are, let's face it, fairly necessary. And even Radiohead will, I’m willing to bet, reappear on the internet soon after their album arrives.

Barbara Speed is a technology and digital culture writer at the New Statesman and a staff writer at CityMetric.