Tag Archives: nanosatellites

Watching a nanosized space rocket under a microscope

That is a silent video depicting the research. For anyone who may be puzzled, there’s an Aug. 8, 2016 news item on Nanowerk featuring the research announcement from Michigan Technological University (Note: A link has been removed),

Researchers at the University of Maryland and Michigan Technological University have operated a tiny proposed satellite ion rocket under a microscope to see how it works (Nanotechnology, “Radiation-induced solidification of ionic liquid under extreme electric field”).

The rocket, called an electrospray thruster, is a drop of molten salt. When electricity is applied, it creates a field on the tip of the droplet, until ions begin streaming off the end. The force created by the rocket is less than the weight of a human hair, but in the vacuum of space it is enough to push a small object forward with a constant acceleration. Many of these tiny thrusters packed together could propel a spacecraft over great distances, maybe even to the nearest exoplanet, and they are particularly useful for Earth-orbiting nanosatellites, which can be as small as a shoe box. These thrusters are currently being tested on the European Space Agency’s LISA Pathfinder, which hopes to poise objects in space so precisely that they would only be disturbed by gravitational waves.

An Aug, 8, 2016 Michigan Technological University news release on EurekAlert, which originated the news item, explains further,

these droplet engines have a problem: sometimes they form needle-like spikes that disrupt the way the thruster works – they get in the way of the ions flowing outward and turn the liquid to a gel. Lyon B. King and Kurt Terhune, mechanical engineers at Michigan Tech, wanted to find out how this actually happens.

“The challenge is making measurements of features as small as a few molecules in the presence of a strong electric field, which is why we turned to John Cumings at the University of Maryland,” King says, explaining Cumings is known for his work with challenging materials and that they needed to look for a needle in a haystack. “Getting a close look at these droplets is like looking through a straw to find a penny somewhere on the floor of a room–and if that penny moves out of view, like the tip of the molten salt needles do–then you have to start searching for it all over again.”

At the Advanced Imaging and Microscopy Lab at the University of Maryland, Cumings put the tiny thruster in a transmission electron microscope – an advanced scope that can see things down to millionths of a meter. They watched as the droplet elongated and sharpened to a point, and then started emitting ions. Then the tree-like defects began to appear.

The researchers say that figuring out why these branched structures grow could help prevent them from forming. The problem occurs when high-energy electrons, like those used in the microscope’s imaging beam, impact the fluid causing damage to the molecules that they strike. This damages the molten salt’s molecular structure, so it thickens into a gel and no longer flows properly.

“We were able to watch the dendritic structures accumulate in real time,” says Kurt Terhune, a mechanical engineering graduate student and the study’s lead author. “The specific mechanism still needs to be investigated, but this could have importance for spacecraft in high-radiation environments.”

He adds that the microscope’s electron beam is more powerful than natural settings, but the gelling effect could affect the lifetime of electrospray thrusters in low-Earth and geosynchronous orbit.

Here’s a link to and a citation for the paper,

Radiation-induced solidification of ionic liquid under extreme electric field by Kurt J Terhune, Lyon B King, Kai He, and John Cumings. Nanotechnology, Volume 27, Number 37 DOI: http://dx.doi.org/10.1088/0957-4484/27/37/375701 Published 3 August 2016

© 2016 IOP Publishing Ltd

This paper is behind a paywall.

Canada’s ‘nano’satellites to gaze upon luminous stars

The launch (from Yasny, Russia) of two car battery-sized satellites happened on June 18, 2014 at 15:11:11 Eastern Daylight Time according to a June 18, 2014 University of Montreal (Université de Montréal) news release (also on EurekAlert).

Together, the satellites are known as the BRITE-Constellation, standing for BRIght Target Explorer. “BRITE-Constellation will monitor for long stretches of time the brightness and colour variations of most of the brightest stars visible to the eye in the night sky. These stars include some of the most massive and luminous stars in the Galaxy, many of which are precursors to supernova explosions. This project will contribute to unprecedented advances in our understanding of such stars and the life cycles of the current and future generations of stars,” said Professor Moffat [Anthony Moffat, of the University of Montreal and the Centre for Research in Astrophysics of Quebec], who is the scientific mission lead for the Canadian contribution to BRITE and current chair of the international executive science team.

Here’s what the satellites (BRITE-Constellatio) are looking for (from the news release),

Luminous stars dominate the ecology of the Universe. “During their relatively brief lives, massive luminous stars gradually eject enriched gas into the interstellar medium, adding heavy elements critical to the formation of future stars, terrestrial planets and organics. In their spectacular deaths as supernova explosions, massive stars violently inject even more crucial ingredients into the mix. The first generation of massive stars in the history of the Universe may have laid the imprint for all future stellar history,” Moffat explained. “Yet, massive stars – rapidly spinning and with radiation fields whose pressure resists gravity itself – are arguably the least understood, despite being the brightest members of the familiar constellations of the night sky.” Other less-massive stars, including stars similar to our own Sun, also contribute to the ecology of the Universe, but only at the end of their lives, when they brighten by factors of a thousand and shed off their tenuous outer layers.

BRITE-Constellation is both a multinational effort and a Canadian bi-provincial effort,

BRITE-Constellation is in fact a multinational effort that relies on pioneering Canadian space technology and a partnership with Austrian and Polish space researchers – the three countries act as equal partners. Canada’s participation was made possible thanks to an investment of $4.07 million by the Canadian Space Agency. The two new Canadian satellites are joining two Austrian satellites and a Polish satellite already in orbit; the final Polish satellite will be launched in August [2014?].

All six satellites were designed by the University of Toronto Institute for Aerospace Studies – Space Flight Laboratory, who also built the Canadian pair. The satellites were in fact named “BRITE Toronto” and “BRITE Montreal” after the University of Toronto and the University of Montreal, who play a major role in the mission.  “BRITE-Constellation will exploit and enhance recent Canadian advances in precise attitude control that have opened up for space science  the domain of very low cost, miniature spacecraft, allowing a scientific return that otherwise would have had price tags 10 to 100 times higher,” Moffat said. “This will actually be the first network of satellites devoted to a fundamental problem in astrophysics.”

Is it my imagination or is there a lot more Canada/Canadian being included in news releases from the academic community these days? In fact, I made a similar comment in my June 10, 2014 posting about TRIUMF, Canada’s National Laboratory for Particle and Nuclear Physics where I noted we might not need to honk our own horns quite so loudly.

One final comment, ‘nano’satellites have been launched before as per my Aug. 6, 2012 posting,

The nanosatellites referred to in the Aug.2, 2012 news release on EurekALert aren’t strictly speaking nano since they are measured in inches and weigh approximately eight pounds. I guess by comparison with a standard-sized satellite, CINEMA, one of 11 CubeSats, seems nano-sized. From the news release,

Eleven tiny satellites called CubeSats will accompany a spy satellite into Earth orbit on Friday, Aug. 3, inaugurating a new type of inexpensive, modular nanosatellite designed to piggyback aboard other NASA missions. [emphasis mine]

One of the 11 will be CINEMA (CubeSat for Ions, Neutrals, Electrons, & MAgnetic fields), an 8-pound, shoebox-sized package which was built over a period of three years by 45 students from the University of California, Berkeley, Kyung Hee University in Korea, Imperial College London, Inter-American University of Puerto Rico, and University of Puerto Rico, Mayaguez.

This 2012 project had a very different focus from this Austrian-Canadian-Polish effort. From the University of Montreal news release,

The nanosatellites will be able to explore a wide range of astrophysical questions. “The constellation could detect exoplanetary transits around other stars, putting our own planetary system in context, or the pulsations of red giants, which will enable us to test and refine our models regarding the eventual fate of our Sun,” Moffatt explained.

Good luck!