Student cubesat demonstrates how to use a solar sail for satellite deorbit

Using cheap off-the-shelf parts students at Brown University have successfully tested a simple solar sail in space and shown how it can be used to de-orbit satellites efficiently and inexpensively.

They built a satellite on a shoestring budget and using off-the-shelf supplies available at most hardware stores. They even sent the satellite — which is powered by 48 Energizer AA batteries and a $20 microprocessor popular with robot hobbyists — into space about 10 months ago, hitching a ride on Elon Musk’s SpaceX rocket.

…The students added a 3D-printed drag sail made from Kapton polyimide film to the bread-loaf-sized cube satellite they built. Upon deployment at about 520 kilometers — well above the orbit of the International Space Station — the sail popped open like an umbrella and is helping to push the satellite back down to Earth sooner, according to initial data. In fact, the satellite is well below the other small devices that deployed with it. In early March, for instance, the satellite was at about 470 kilometers above the Earth while the other objects were still in orbit at about 500 kilometers or more.

Based on the data, it is expected the cubesat will burn up in the atmosphere in five years, not twenty-five or so predicted for the other cubesats launched to the same orbital elevation.

This experiment above all proves that most of the very expensive demo missions to test this kind of technology have been grossly over-budget. The entire cost of this student-built project was just $10,000, and it actually was more successful in proving this technology than a number of past solar sail projects that cost millions.

Test of solar sail for de-orbiting smallsat ends successfully

Capitalism in space: The Canadian company Space Flight Labs announced yesterday that its first test of a solar sail for de-orbiting a small satellite ended successfully last month.

The CanX-7 (Canadian Advanced Nanospace eXperiment-7) was a three-kilogram, 10x10x34cm satellite that was launched on September 26, 2016. The satellite was funded by the Defence Research and Development Canada, the Natural Sciences and Engineering Research Council, COM DEV Ltd. (now Honeywell), and the Canadian Space Agency.

According to SFL [Space Flight Labs] “the satellite successfully completed a seven-month aircraft tracking campaign before deploying its drag sails in May 2017 to demonstrate drag-sail based deorbiting.” SFL said it took five years for the drag sail to deorbit the satellite and without it the satellite wouldn’t have burned up in the atmosphere for roughly another 178 year.

When the four drag sails, each about one square meter in size, were deployed, engineers immediately measured an increase in the orbital decay rate. Though it still took five years to force a de-orbit, the system removed the satellite from orbit much sooner than otherwise.

The system is aimed at the smallsat market, satellites too small for other proposed removal methods that also might remain stranded in orbit for a very long time because of their small size.

French company raises €2 million to launch commercial solar sail

Capitalism in space: The French startup Gama has successfully raised €2 million to build and launch its first test solar sail, with the goal of eventually selling those sails for other interplanetary missions.

Gama plans to deploy a 73.3-sq-metre solar sail in a 550km-altitude orbit in October. It will be launched as an additional payload on a SpaceX rocket.

There have been a number of previous solar sail deployment tests by Nasa and the American space advocacy group the Planetary Society. However, the Japan Aerospace Exploration Agency had been the only organisation to successfully sail on sunlight. In 2010 it used a solar sail to power the experimental Ikaros (Interplanetary Kite-craft Accelerated by Radiation of the Sun) spacecraft to Venus.

If successful the company will follow with two more test missions in ’24 and ’25, first testing at higher orbit and testing in interplanetary space.

Using lasers to travel to the stars

The competition really heats up! A research team at the University of California, Santa Barbara (UCSB) has proposed that an array of space-based lasers can be used to accelerate a solar sail to speeds as much as 26% the speed of light, thus making interstellar travel possible.

[The] key breakthrough was the development of modular arrays of synchronized high-power lasers, fed by a common “seed laser.” The modularity removes the need for building powerful lasers as a single device, splitting them instead into manageable parts and powering the seed laser with relatively little energy. Lockheed Martin has recently exploited this advance to manufacture powerful new weapons for the US Army. In March last year, the aerospace and defense giant demonstrated a 30 kW laser weapon (and its devastating effect on a truck). By October, the laser’s power had already doubled to 60 kW and offered the option to reach 120 kW by linking two modules using off-the-shelf components.

The UCSB researchers refer to their own planned arrays as DE-STAR (Directed Energy System for Targeting of Asteroids and ExploRation), with a trailing number to denote their size. A DE-STAR-1 would be a square array 10 meters (33 ft) per side and about as powerful as Lockheed’s latest; at the other end of the spectrum, a DE-STAR-4 would be a 70 GW array covering a massive area of 100 square kilometers (39 square miles).

…Lubin stresses that even a relatively modest orbital array could offer interesting propulsion capabilities to CubeSats and nanosatellites headed beyond Earth orbit, and that useful initial tests would still be conducted on the ground first on one-meter (3-ft) arrays, gradually ramping up toward assembling small arrays in orbit. While even a small laser array could accelerate probes of all sizes, the larger 70-GW system would of course be the most powerful, capable of generating enough thrust to send a CubeSat probe to Mars in eight hours – or a much larger 10,000-kg (22,000-lb) craft to the same destination in a single month, down from a typical six to eight.

Further upgrades would make it possible to send a cubesate and its lightsail to Alpha Centuri in about fifteen years.

The important point here is that it appears that all the technology for building this already exists, or is relatively straightforward to develop.

LightSail successfully deploys solar sail

Engineers have confirmed that the cubesat prototype LightSail has successfully deployed its solar sails.

This is I think only the second time a solar sail has successfully deployed in space. More significant to me is the fact that it is the first time this kind of complex engineering test has been tried using a cubesat. If cubesats can begin to handle these kinds of tasks, unmanned satellite technology is going to take a gigantic leap forward.

LightSail back in business?

The Planetary Society’s solar sail engineering test called LightSail has re-established communications with the ground, allowing for the possibility that it can finally achieve its solar sail deployment, the main purpose of the mission.

I had previously reported that the sails had deployed, but a commenter correctly noted that only the panels have deployed, not the sails themselves, which need full battery power. The communications problem has been related to a battery charging problem. They are hoping that the batteries will get charged by mid-day today when they will try to deploy the sails.

NASA announces awards for three technology demonstration space missions

NASA has announced three awards for technology demonstration space missions, all set to fly within four years. More details here.

The three missions are:

  • A solar sail demonstration mission, flying a sail 38 by 38 meter sail.
  • A demonstration of in-space laser/optical communications technologies.
  • The use of a high-precision atomic clock in space.

I especially like the solar sail mission because of its long range possibilities, though the other technologies would probably be put to practical use more quickly.