As a reader of this column, you have a stake in a satellite that will be launched later this year. Our space correspondent explains.
We leave daylight behind as we descend the stairs into a long dimly lit corridor, lined with pipes, wires and ventilation ducts. Our footsteps echo on the concrete floor as aging fluorescent tubes flicker above us. Eventually, about midway down, we find the unmarked door we’re looking for. Here, in the unlikely surroundings of a windowless basement laboratory at Nasa Ames in California, a revolutionary spacecraft is taking shape.
Cornell University graduate student Zac Manchester has been lent this lab to develop KickSat. This 30cm- (12in-) long satellite will contain 200 even smaller satellites, he’s called sprites. Around the size of a couple of postage stamps, these are probably the smallest spacecraft ever developed.
Not only is the design of this space project unique but also the way it is being funded. Money for KickSat has been raised through the crowd-funding website Kickstarter and the sprites are allocated to the project’s supporters. Last year, BBC Future and the Space Boffins podcast paid the $300 on your behalf and I have travelled to meet Manchester to see what we are getting for our investment.
“I’d like to think of it as the people’s satellite,” says Manchester. “We’re pushing towards a personal satellite, where you can afford to put your own thing in space.”
The sprites look more circuit board than satellite but despite being just 3.5 cm (1.5in) square and only a few millimetres thick, they are packed with technology. “Half the board is taken up with a solar array, then there’s a microcontroller – like a little computer,” Manchester explains, holding one of the sprites carefully between his finger and thumb. “Then we have a radio transceiver and two sensors – a magnetometer and a gyroscope.” These instruments enable the devices to sense the Earth’s magnetic field and take readings of orientation and spin. “We want to see how these come out of the mother ship, KickSat, and how they’re spinning after that.”
This KickSat mother ship is made up of three 10 cm (4in) cubed units, known as Cubesats. One of these sections will contain the control systems for the spacecraft and the remaining two will carry the sprites. KickSat is designed to be launched as a “piggyback” payload alongside another satellite and, once released into orbit, the sprites will be ejected.
Manchester has used a 3D printer to create a full-sized copy of KickSat to demonstrate how it works. It looks a bit like a shoebox with a door at the end. “There’s a plunger mechanism that holds the 200 sprites in place,” he says. “When we trigger the deployment from the ground station, we’ll release the spring and the whole thing will pop out releasing the sprites into space.” He tips the box and mock-up plastic sprites scatter across the floor.
Unfortunately, it’s not quite that simple. As the sprites are solar powered, for them to function correctly, it is essential that when they are released they are pointing at the Sun. To achieve this, KickSat will be orientated towards the Sun before being spun around its axis, to allow centripetal force to propel the sprites away from each other as they spew out into space.
So they can radio back to Earth, it is also crucial that the antennas deploy correctly. These are made Nitinol or memory-metal – thin strands of wire that always revert to their original shape. These whiskers of metal will be coiled up tight within KickSat and spring out when they are released.
“The idea is that they’ll be attached to each board, coiled up in the footprint of the board, and when they pop out, the antennas will unfurl,” says Manchester. But with 200 sprites packed into a space just 10cm by 20cm, each with a tightly coiled length of wire attached, whoever packs them up is going to have a tough job on their hands. “That’s what undergrads are for,” jokes Manchester.
Funding the development of these remarkable satellites is only one aspect of KickSat supporters’ involvement. The most exciting part comes once the sprites make it into orbit. Each one will transmit a unique identification code – anything up to ten digits – that can be picked up by receivers on the ground. Anyone who builds a ground station will be able to track their own personal spacecraft as it orbits the Earth.
“You can choose what it transmits,” says Manchester. “We’re working on a ground station design that’s going to be as cheap as possible, so you’ll, in theory, be able to stick an antenna up on your roof and listen to your own satellite.”
As a non-commercial project, KickSat is being launched – for free – under Nasa’s Educational Launch of Nanosatellites programme. But the deadline is tight. Because of the low orbit the sprites are being ejected into (which means they will only last a few months before burning up in the Earth’s atmosphere), the project has been bumped up the waiting list and is currently due for launch in September this year alongside a SpaceX Dragon capsule destined for the International Space Station.
“The schedule is hectic,” admits Manchester. “We weren’t expecting to launch this soon. But we’ve got to meet the deadline…so we will.”
Although the motivation for many KickSat supporters is simply getting something with their name on it into space, Manchester hopes others will take inspiration from the project. “Right now this is more or less Sputnik on a chip,” he says. “I guarantee in a couple more years there will be way more things you can pack on these and you’ll be able to do a lot more with them.”
They will also become more affordable. Although the price of the components for a sprite comes in at just $25, if Nasa was not footing the bill for the launch, it would cost the equivalent of $1000 to get each one into orbit. But, as technology gets smaller, imagine a spacecraft half the size with twice the capability. “We’re talking a high school class putting one of these together and doing it as a project,” says Manchester. “By doing it first and putting everything out there in the public domain, other people can do it again.”
If the people’s satellite succeeds, then the potential is enormous. For the price of an iPhone, you could have your own spacecraft.
Welcome to the era of personal spaceflight.
We need suggestions for the unique identification code that our satellite will transmit. It can be up to ten characters (letters or numbers). Other than that, it is completely up to you. We will take ideas on the BBC Future Facebook page to help decide an eventual call sign. I should point out that this is not a competition, there are no prizes and we will make the final decision.
In the meantime, Manchester has sent me a working sprite and I am going to get started on building a ground station. Given that I last attempted an electronic circuit twenty-five years ago and still bare the scars from the resulting soldering accident, this should be an interesting experience. I’ll be soliciting help from some fellow space geeks and will keep you posted in my podcast and in this column as we, hopefully, progress. You can also follow Zac’s blog about the project.