420 magical seconds in space

Dec 19, 2011 By Sara Perrin
Credit: 2011 EPFL

(PhysOrg.com) -- A new tool to calculate the orientation of a satellite with respect to the Earth, developed by EPFL students, will be on board a European Space Agency rocket scheduled to launch in March 2012. This will be an opportunity to test the tool in ideal microgravity conditions.

An elegant , developed by a group of ten EPFL students, will take flight next March on a rocket launched in Sweden. The product of more than a year’s work, it was accepted by the (ESA) after a lengthy selection process.

The project offers a new method to calculate the of a with respect to the . This is a very important function, because whether the goal is telecommunications or taking pictures, satellites need to be pointed precisely towards Earth to work optimally.

The – called the Gravity Gradient Earth Sensor - measures the gradient of gravitational forces, in other words, the rate at which gravity decreases as you go further away from the center of the Earth. Very thin, precise sensors developed in EPFL’s Microsystems for Space Technologies Lab in Neuchâtel can capture changes as small as a tenth of a nanometer, the order of magnitude of a single atom.

Finding the Earth

The problem is simple: as was experienced by SwissCube, a satellite launched into orbit can end up tumbling around in all directions. How can it position itself? The solution is instinctive: find the Earth, and orient itself accordingly!

“Up to now, optical sensors were used to find Earth using infrared emissions,” explains Hervé Meyer, a scientist in EPFL’s . “But that’s a very sensitive technique, which must be installed on the exterior of the satellite. It’s thus very exposed and very fragile. The tool we’re developing is protected, inside the satellite.”

It’s impossible to test the precision of the new tool under terrestrial conditions, because the effects of gravity are too strong. It can only be tested in microgravity conditions, where the forces of the gravity field still exist, but are much weaker. To attain these conditions, the tool can be placed on a rocket launched into a parabolic flight trajectory. The rocket that will carry the four test sensors, enclosed in a ten-centimeter cube resembling the SwissCube picosatellite, will fly up to an altitude of 100 km.

Concrete and rewarding

The rocket’s flight will last about 13 minutes, but it will only be in microgravity conditions for about 420 seconds. The team will have to make the most of this valuable time to take all the data they need. In particular, they’ll be measuring the effects of acceleration and rotation.

“It’s a very concrete and rewarding project that taught students a lot not only about how an institution like ESA functions, but also about how to work in a multidisciplinary team, with people coming from fields like microengineering, electronics and materials science,” notes Muriel Richard, senior scientist in EPFL’s Space Center. The Space Center offers regular technical and logistical guidance for student projects in space technologies.

Explore further: Bright points in Sun's atmosphere mark patterns deep in its interior

Provided by Ecole Polytechnique Federale de Lausanne

4.8 /5 (6 votes)
add to favorites email to friend print save as pdf

Related Stories

UMaine students test wireless sensors on rocket

Apr 27, 2011

Five University of Maine students participated in a recent launch process as a rocket loaded with wireless sensors the students developed in a UMaine lab blasted off in California’s Mojave Desert.

Iridium Next Prepares to Ride the Falcon

Apr 14, 2011

To date, Iridium NEXT is the largest commercial space launch contract with any single entity. All total, the contract is worth an estimated $492M. Iridium Communications Inc. signed into a deal with Space ...

Space mission tells of Antarctic melt

Sep 13, 2011

(PhysOrg.com) -- A team of researchers from The Australian National University has been selected from a competitive field to participate in NASA’s Gravity Recovery and Climate Experiment (GRACE) Science ...

Hylas-1 ready for service

Mar 25, 2011

It’s all systems go for Hylas-1, the first satellite created specifically to deliver broadband access to European consumers. Since its launch in November, Hylas has performed well throughout its testing ...

Recommended for you

Astronauts to reveal sobering data on asteroid impacts

18 hours ago

This Earth Day, Tuesday, April 22, three former NASA astronauts will present new evidence that our planet has experienced many more large-scale asteroid impacts over the past decade than previously thought… ...

Rosetta instrument commissioning continues

19 hours ago

We're now in week four of six dedicated to commissioning Rosetta's science instruments after the long hibernation period, with the majority now having completed at least a first initial switch on.

Astronaut salary

19 hours ago

Talk about a high-flying career! Being a government astronaut means you have the chance to go into space and take part in some neat projects—such as going on spacewalks, moving robotic arms and doing science ...

Red moon at night; stargazer's delight

Apr 16, 2014

Monday night's lunar eclipse proved just as delightful as expected to those able to view it. On the East Coast, cloudy skies may have gotten in the way, but at the National Science Foundation's National Optical ...

User comments : 0

More news stories

Cosmologists weigh cosmic filaments and voids

(Phys.org) —Cosmologists have established that much of the stuff of the universe is made of dark matter, a mysterious, invisible substance that can't be directly detected but which exerts a gravitational ...

Hubble image: A cross-section of the universe

An image of a galaxy cluster taken by the NASA/ESA Hubble Space Telescope gives a remarkable cross-section of the Universe, showing objects at different distances and stages in cosmic history. They range ...

Scientists tether lionfish to Cayman reefs

Research done by U.S. scientists in the Cayman Islands suggests that native predators can be trained to gobble up invasive lionfish that colonize regional reefs and voraciously prey on juvenile marine creatures.

Leeches help save woman's ear after pit bull mauling

(HealthDay)—A pit bull attack in July 2013 left a 19-year-old woman with her left ear ripped from her head, leaving an open wound. After preserving the ear, the surgical team started with a reconnection ...