Cubesats: small satellites with great potential

three satellite images of the earth

Featured image: Cubesats will be released from the international space station. Credit: ESA / NASA-A. Barley

Smartphones have not only changed the world, they also change space. Over the past decades we have looked at how manufacturers furiously struggled to develop faster, leaner and high-quality components for use in the latest phones. But it appears that the growth of mobile components is also useful for the satellite company.

Since they were first proposed in 1999, a community has developed around the idea of ​​building satellites that are considerably smaller and cheaper to launch, partially built on the basis of newly classified components. The idea is that these & # 39; cubesats & # 39; can be sent to space, potentially dozens at a time, and piggyback on other space missions as secondary payloads.

On 12 June 2013, an Atlas rocket was fired from the air base Vandenberg in California with several satellites. The largest was a satellite communication satellite of seven tons – and the smallest were a few cubesats each weighing less than 2 kg, the AeroCube 5a and 5b.

A & # 39; camera phone in space & # 39;

Launched by the Aerospace Corporation, AeroCubes' primary mission was to test a new communication technology, but after their launch, Dee W Pack from The Aerospace Corporation was used differently. He used their built-in camera's to prove that cubesats are equally capable of making photos of the earth as full-sized satellites.

"The thought came to me that the small cameras that we had on some of our AeroCubes – our Aerospace cubesats – could be used at night," says Pack. Inspired by the incredible night photography of a colleague at the National Oceanic and Atmospheric Administration, and thinking of the impressive photography that astronaut Donald Pettit from the international space station managed to manage, he wanted to see how cubesats adapted.

The image on the left was taken by an astronaut aboard the international space station ISS; the two on the right were taken by the AeroCube cubesats

Technically, the built-in cameras are probably not even as high as the camera in your phone: "They are megapixel cameras, but they do not meet current standards because they were built a few years ago, and they are equipped with very cheap lenses, "explains Pack. "The trick is in pointing the satellite, so you can expose the small camera about 0.2 or 0.3 seconds and get a slightly longer exposure so that your image does not slip".

But this limited possibility does not mean that the cubesats cameras can not be usable, even compared to photography of the hugely expensive VIIRS, a full-sized infrared camera aboard a full-sized satellite. For certain applications, the camera on the AeroCubes is even better: not only is it full-color, but the satellites are in a lower lane. They can make images from the ground with a resolution of about 100 m for each pixel, instead of the 740m of VIIRS. This means that you can see individual streets – and that is exactly what you need if, for example, you want to monitor urban growth or light pollution.

Up-to-date footage

Another intriguing application currently under development is & # 39; GPS occultation & # 39 ;. The idea is that a cubesat can be used to receive GPS signals that have traveled through the earth's atmosphere, and to measure how the signals are broken, so that scientists can make even more accurate weather forecasts.

Perhaps the biggest advantage of using cubesats is that normal satellites can not replicate cheaply: & # 39; refresh rate & # 39 ;. Geostationary satellites, which maintain a fixed position relative to the earth, can only circle around the equator, which is not useful for aerial photography or other types of observations. Satellites photographing the earth must be in less regular lanes, which means that they will not always be above the same places – that is why Google Maps only refreshes its footage every few years. But this is only a problem if you only have one huge, expensive camera.

Close-up image of a cubesat being treated by an engineer

Their small size means that dozens of cubesats can be launched on one space mission. Credit: NASA

(Image: © Nasa)

Because cubesats are cheaper and easier to make, they are easier to launch massively – so you could have lots of satellites with lots of cameras, make more photos, and buzz more frequently over us.

"If you can get a large number of sensors in orbit around the earth, you start to get it […] almost real-time updates of what is happening at a certain point on the planet, and this has very interesting earth science applications in terms of being able to track changes [such as] the aftermath of severe weather conditions, "says Chris Baker, who runs NASA's Small Spacecraft Technology program, and also points to an intriguing future in which CubeSats can effectively become an early-warning system.

"It requires a certain degree of autonomy, but say that if the spacecraft can detect the initiation of that forest fire, it can alert assets on the ground, or possibly alert a larger alarm. [satellite] in a job [saying]: & # 39; Hey, there's something interesting here, turn your camera in this direction and take a picture with a higher resolution so we can see what's going on & # 39 ;. "

Less costs, less risk

The most exciting, however, is the second-order consequence of cheaper launches: faster innovation.

"Until recently, the aerospace industry was extremely risk-averse," said Rafael Jorda-Siquier, CEO of Open Cosmos, an Oxford-based space startup who wants to launch space for just £ 500,000 (about $ 650,000 or AU $ 900,000). He says that space technology has traditionally been stuck in what he calls a "vicious circle." calls.

"The more expensive the technology is, the more you want to test on the ground, so you can be sure it works," he says. "You end up with a huge satellite, [that’s] very expensive, all too much developed and in many cases with the help of old technology. In space, this usually means using outdated technologies and flying with microchips from the 1980s. "

Cubesats can short-circuit this cycle and upgrade space technology faster, because they can be built less costly and less money is at risk if they do not work or go wrong.

A concept image of the Orion capsule from NASA. Technology tested in cubesats can eventually be used to bring astronauts to Mars

A concept image of the Orion capsule from NASA. Technology tested in cubesats can eventually be used to bring astronauts to Mars

"The fact that some of these spacecraft deport fairly quickly is seen by some in the industry as an asset because they already have the next generation waiting for the launch," notes NASA's Chris Baker. And the best part? Technology masters on cubesats could ultimately help us to take us to Mars.

"The scale of what is possible on a small satellite is actually not so far removed from the scale required for a manned vehicle," says Baker, who is considering NASA's new Orion space capsule for people currently under development .

"Although that is a large spacecraft, most of the space is dedicated to humans, for example, a communication system that is on a cubesat would certainly be on the Orion crew, so there is the potential for the technologies being tested for small spacecraft to provide early and more frequent opportunities to test mission-building capabilities for human exploration. "

So maybe when people are finally on their way to Mars, they can be on the move thanks to a small push from a few rather small satellites.

James O & # 39; Malley tweets like @Psythor.

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