女生小视频

(Image: Spencer Wilson)

New 女生小视频 has a plan to beat ESA to Jupiter鈥檚 moon with our own low-budget CubeSat space probe. We鈥檒l be looking for alien life 鈥� who鈥檚 in?

WE鈥橰E normally a patient lot at New 女生小视频. We know science takes time. Even so, we鈥檝e been reporting on the possibility of life on Europa, Jupiter鈥檚 ice-encrusted moon, since the mid-1990s. Now, two decades on, we鈥檙e facing another 15 years or more until NASA or the European Space Agency visit it with a spacecraft capable of telling us more.

Frankly, we just can鈥檛 wait that long to see what鈥檚 out there. So we thought, why wait at all? It鈥檚 the 21st century. Who leaves it to governments or international space agencies to fulfil their dreams? This is the age of do-it-yourself, crowdsourced everything. Hence the New 女生小视频 mission to Europa. You鈥檙e welcome.

To the untrained eye, Europa looks like a wildly expensive destination. ESA鈥檚 , or JUICE, will make two dedicated fly-bys at an estimated cost of 鈧�1 billion. True, that includes a look at Jupiter, Callisto and Ganymede, but still. The price tag on NASA鈥檚 proposed mission is just as high.

Given these eye-watering estimates, you might be doubting whether anyone can crowdfund a space mission. Hey, it鈥檚 already been done. It鈥檚 exactly how more than 2000 space enthusiasts raised upwards of $160,000 to reboot an old NASA solar explorer mission called ISEE-3. It was enough for NASA to hand control of the craft to the rebooters. And not reluctantly, either: in September, NASA issued a report called 鈥溾�� that acknowledged the power of crowdfunding for space missions and called it 鈥渁 way to have citizens participate with NASA in a way never before possible鈥�. Thanks to platforms like Kickstarter and Rockethub, there is 鈥渁n opportunity for Americans from all walks of life to be an integral part of NASA鈥檚 team鈥�.

But maybe you鈥檙e not American. Maybe you don鈥檛 want to be on NASA鈥檚 team. Maybe you want to be on Team New 女生小视频. You will when we tell you our craft鈥檚 name. Let鈥檚 hear it for TEENSY: the Tiny Europa Explorer by New 女生小视频 and You.

You want some background before signing up? Well, there are good reasons to go to Europa. For a start there鈥檚 liquid water, lots of it. Starting with a few hints in early magnetic field measurements and progressing to certainty thanks to the Hubble Space Telescope, we now know it is there beneath the moon鈥檚 icy crust. No one is sure how deep the ice goes; it could be just a few kilometres thick, or anywhere up to 30 kilometres. But beneath it sits a huge ocean. Not only is it roughly twice the volume of Earth鈥檚 oceans, there鈥檚 evidence that these seas could contain the ingredients for life.

That comes from the curious criss-cross of scars on the moon鈥檚 surface that are believed to be a result of Jupiter鈥檚 gravity stretching and squeezing it. That creates heat, causing ice to melt and refreeze, and also generates convection currents in the water. This circulation would drag minerals up from the moon鈥檚 silicate mantle, producing a mix of chemicals that could nurture life. The moon even has a thin, oxygen-rich atmosphere that could help sustain living creatures and make Europan life not dissimilar to that of primordial Earth. 鈥淚t is a very good candidate when thinking of habitability or the existence of 鈥榣ife鈥� beyond the Earth,鈥� says Emma Bunce of the University of Leicester and a member of the JUICE science team.

And, amazingly, we might not even have to go under the ice crust to find it. At the end of last year, Hubble recorded images of vast water plumes shooting into space. The plumes were 200 kilometres high and our best estimates suggest that they fire out 3000 kilograms of water every second. That means if there is life in the Europan oceans, it could be detected by intercepting the plumes in a passing spacecraft. Our passing spacecraft. Surely you want to be involved with the first craft to fly through a water jet teeming with alien life?

鈥淪urely you want to be involved with the first craft to fly through a water jet containing alien life鈥�

Small is big

You鈥檙e probably wondering whether TEENSY could possibly do such amazing things, given 鈥� as the name suggests 鈥� its diminutive size. Not a problem: in space travel, small is the new big.

We鈥檙e talking CubeSats, standardised 10-centimetre cubic modules for building spacecraft. Their creators at California State University Polytechnic have been astonished at their popularity. CubeSats have been used to sample Earth鈥檚 atmosphere, monitor shipping and help detect earthquakes; more than 100 little boxes have been launched so far, and scores of missions are under construction. There are even stores, like the one run by Clyde Space, a CubeSat designer and manufacturer in Glasgow, UK, that allow you to . 鈥淭he technology is very well suited to a range of applications,鈥� says Chris Brunskill of the , a UK company that helps businesses take advantage of the country鈥檚 growing space industry.

Their appeal lies in the standardisation: you stuff the cubes with cheap, off-the-shelf components that will perform a unique task. But externally they are all identical, which makes launch easy and reliable 鈥� even if you choose to connect two or three together, as is now becoming common. 鈥淵ou can go to a launch provider with a CubeSat and they know there鈥檒l be no issues, which is very different from a bespoke satellite,鈥� Brunskill says.

Traditional launch is on a rocket equipped with a Poly-PicoSatellite Orbital Deployer, or P-POD. Once in low Earth orbit, it throws a bunch of CubeSats out into space to do their work. There鈥檚 a new alternative, though 鈥� you can put your CubeSat on a Soyuz or SpaceX craft bound for the . There, an astronaut will kick it out into space for you.

It鈥檚 surprisingly cheap. We鈥檝e been told it will cost about 鈧�130,000 to have an ISS astronaut throw a couple of kilograms out of the airlock. New 女生小视频 has over four million readers worldwide; divided between us that鈥檚 pennies.

Of course there鈥檚 the 500 million kilometre plus journey to Jupiter. This is a new frontier for CubeSats: the standard procedure is for the module to sit in low Earth orbit for just a few days before it is allowed to fall back to Earth.

But moving away from Earth shouldn鈥檛 be a problem. As for a propulsion system, 鈥淚f you have a can of deodorant 鈥� some kind of pressurised canister 鈥� that鈥檚 essentially it,鈥� says Adam Masters of Imperial College London, who鈥檚 also on the JUICE team.

Mission control

We can probably do a bit better than a spray can. Take Benjamin Longmier鈥檚 CubeSat xenon engine, for example. Longmier, who works at the University of Michigan, starts his engine by ionising xenon gas to form a plasma. Once that plasma has formed, an electric field accelerates it towards the back of the CubeSat, pushing the craft forward.

Longmier鈥檚 thrusters give about 10 watts of power. It鈥檚 not a lot 鈥� about two cellphones鈥� worth, as he puts it 鈥� but it would be enough to get to Europa eventually. About a year after a launch into a low Earth orbit, it would be capable of around 17 kilometres a second. 鈥淭hat means it could go just about anywhere in the solar system,鈥� Longmier says.

An alternative would be Martin Tajmar鈥檚 field emission electric propulsion engine. It uses liquid metal as a propellant and is just 1 centimetre in diameter. 鈥淵ou apply a voltage and it generates an ion beam,鈥� says Tajmar, who works at the Technical University in Dresden, Germany. 鈥淚t鈥檚 small but highly capable: you can generate thrusts from a few microNewtons to tens of microNewtons. For a small satellite this is a lot.鈥�

One advantage is its efficiency 鈥� more than 90 per cent of the propellant generates thrust. 鈥淭hat鈥檚 an order of magnitude above pulse plasma thrusters,鈥� Tajmar says.

So better than a spray can, then. But is it better than the hot new technology of solar sailing? This uses nothing more than the gentle pressure exerted by sunlight to cruise through space. With a solar sail, there鈥檚 no propellant to carry and no worries about it running out.

The power does diminish as you get further from the sun, but if TEENSY has already accelerated to the speed it needs, there鈥檚 nothing to stop it sailing on to Europa, in theory. The Japanese IKAROS probe has already shown that solar sailing to another planet is possible. Although not a CubeSat, it glided past Venus in December 2010 and is still on its way through the solar system.

A CubeSat could set sail, too. If the Planetary Society can successfully crowdfund its module, it is scheduled to launch in May 2016 and it will have four ultra-thin mylar sheets that unfurl beyond low Earth orbit. 鈥淪ending a CubeSat to Jupiter is not unrealistic,鈥� says of Armagh Observatory in the UK, 鈥渂ut you do have to be innovative.鈥� He estimates that TEENSY could reach Jupiter in 5 to 10 years.

So we have power to boldly go, but nobody has operated a CubeSat in deep space. Can it be done? The people behind think so. It has no launch date as yet, but INSPIRE aims to demonstrate that a CubeSat can communicate, navigate and perform useful functions beyond low Earth orbit. 鈥淲e have a mission objective of reaching at least 1.5 million kilometres,鈥� says mission leader Andrew Klesh. 鈥淥ur minimal objective is 400,000 kilometres, that鈥檚 lunar distance from Earth.鈥�

So far, so good. Assuming TEENSY can get from the drawing board all the way to Europa, what equipment should she be carrying?

The big space agencies have already outlined what they鈥檇 like to do. Their list includes examining what Jupiter鈥檚 radiation does to the Europan environment; measuring the thickness of the ice crust and examining its surface features; identifying a suitable landing site for a future mission and, of course, sampling the ocean.

The kind of tools needed for these tasks are quite daunting 鈥� and heavy. So far, 11 have been selected by the big missions. Among them are: an ice-penetrating radar, an infrared spectrometer, a topographic imager, a mass spectrometer, a magnetometer, an antenna for radio gravity tracking, a high resolution camera and a thermal imager.

It鈥檚 hard to imagine packing all that into a CubeSat. So we are going to have to make some difficult decisions.

The ideal ice-penetrating radar, one that can see at depths of 30 kilometres, has a mass of 42 kilograms. A bit big, then. Even if we downsize to one that penetrates 3 kilometres, according to , it would still be 12 kilograms. So maybe we could leave measuring the thickness of Europa鈥檚 ice crust to the latecomers.

Likewise with an infrared spectrometer for examining the composition of the icy surface, which weighs in at 19 kilograms. But a mass spectrometer, to analyse molecules captured from a plume of water and gas, could require as little as 7 kilograms of the allowance. That seems OK. We could couple that with a 4-kilogram camera 鈥� sorry, topographic imager 鈥� that will give us close-up pictures of the surface and maybe show where a future mission could land.

So, with 11 kilograms of instruments we could hope to encounter a plume for analysis, and photograph the moon鈥檚 surface. And that鈥檚 just with the kit around at the moment. 鈥淭here鈥檚 a lot of drive to make instruments smaller, motivated by the potential of the CubeSat platform,鈥� says Masters.

Flagship missions like Europa Clipper and JUICE have to use tried and trusted, entirely reliable technology. But we could gamble, and take something like MAGIC, the tiny magnetoresistive magnetometer developed by researchers at Imperial College London to measure the magnetic field in low Earth orbit. It鈥檚 not quite up to the sensitivity we鈥檇 want for Europa, but it has and there鈥檚 still time to develop it further before launch.

We鈥檙e confident we can get some useful instruments on board, then. There is just one problem remaining. How are we going to find out what TEENSY has discovered?

鈥淐ommunication from there back to Earth? With an antenna the size of a pencil?鈥� Tajmar actually laughs out loud at the idea. 鈥淣ot a chance!鈥� he says. This could be a fatal flaw. Klesh has thought this issue through for the INSPIRE project, and doesn鈥檛 exactly inspire confidence. 鈥淥ur communications link holds strong well past 1.5 million kilometres, but we will reduce our data rate accordingly as we get further and further away,鈥� he says. After that, they will only send what is absolutely critical. 鈥淎t some point, we will drift further away from Earth than we might be able to communicate, but this will be well beyond our mission objectives.鈥� Those objectives, remember, top out at 1.5 million kilometres. Europa is nearly 400 times that distance from Earth.

Strength in numbers

We could rely on the rapid rate of progress in CubeSat and space technology to come to our rescue, but really, we can鈥檛 stake everything on that. We have to find a realistic solution 鈥� and there is one. It鈥檚 not ideal, but it looks like the only option at the moment. We have to wait for NASA to arrive at Europa, with CubeSats.

In October, the Jet Propulsion Laboratory in California announced it was considering taking an extra load aboard the Europa Clipper: a bunch of CubeSats that would making measurements from multiple views. Although there鈥檚 no guarantee any CubeSats will make it onto the Europa Clipper, they are worth investigating, says project manager Barry Goldstein. 鈥淭hey鈥檝e been showing significant promise in their ability to adapt for deep space missions,鈥� he says. 鈥淭hat doesn鈥檛 mean we鈥檝e proven it, but it鈥檚 certainly a good thing to have in your hip pocket.鈥�

If they make it on board, those sats will have to upload their data to the Clipper, which would have a powerful enough antenna to beam it all back to Earth. And if NASA鈥檚 CubeSats can talk to the Clipper, so can ours.

As soon as the mothership arrives, TEENSY can wake from an energy-conserving hibernation and relay our hard-won data back to Earth. That can happen before the Clipper mission has gathered a scrap of its own data. So, although we would be later than we鈥檇 like in delivering the news of life on Europa, our TEENSY would still be the first to detect it. That鈥檚 good enough, isn鈥檛 it? Who鈥檚 in?

This article appeared in print under the headline 鈥淏y Jupiter, we really can go to Europa鈥�