NASA’s GRACE-FO Satellites Turn On Their Lasers To Find Each Other In Earth’s Orbit


About three weeks after their launch, the twin climate-monitoring satellites that NASA deployed in Earth’s orbit have switched on their powerful lasers for the first time, showing that their systems are shipshape.

As reported by the Inquisitr, the twin GRACE-FO satellites (short for Gravity Recovery and Climate Experiment Follow-On) soared to the skies on May 22 atop a SpaceX Falcon 9 rocket.

Their first goal was to position themselves over our planet at a distance of roughly 137 miles (220 kilometers) from one another, so that they could later act as a single instrument and measure the variations in Earth’s gravitational field as it produces changes in the distance between them.

Having already maneuvered themselves into the designated position, the two GRACE-FO satellites successfully fired their lasers on June 13 to search for one another, NASA announced at the beginning of the week.

In order to pull this off, the tiny spacecraft have achieved something truly amazing — a genuine feat of engineering that Gerhard Heinzel, from the Max Planck Institute for Gravitational Physics (Albert Einstein Institute) in Hanover, Germany, described as “mind-boggling.”

Managed by NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California, in collaboration with the German institute, the GRACE-FO satellites are equipped with a laser ranging interferometer (LRI) instrument — a piece of demonstration technology meant to prove that it can lead to significantly more accurate measurements during future satellite missions, Engadget reported earlier today.

In order to find each other, the small satellites had to point their lasers at a specific location on the surface of their twin — a coin-sized hole that the LRI had to hit from the 137-mile distance “while both spacecraft race around Earth at 27,000 kilometers an hour [16,000 miles per hour],” said Heinzel.

Not only did the LRI perform up to par, but it also succeeded in linking up the two satellites on the very first try, noted Christopher Woodruff, head of the LRI mission operations at JPL.

The LRI also “delivered its first intersatellite range data at a later downlink that day,” enabling the two spacecraft to beam their first range data back to the ground team, stated NASA officials.

LRI Instrument Manager Kirk McKenzie of JPL commented on the significance of this demonstration technology.

“The LRI is a breakthrough for precision distance measurements in space. It’s the first inter-spacecraft laser interferometer and the culmination of about a decade of NASA- and German-funded research and development.”

The GRACE-FO ground team will now spend several weeks to months fine-tuning the satellites’ laser instruments and making sure they can decode the data that the spacecraft are transmitting.

As the Inquisitr previously reported, the GRACE-FO satellites are tasked with taking accurate readings of Earth’s gravity field with both their microwave ranging interferometers — the instruments of the original GRACE satellites, which operated from 2002 until last year — and the new-generation LRI.

These measurements will allow the spacecraft to detect the monthly movements of water, ice, and crust on our planet and help scientists keep track of the thinning ice sheets, the rising sea levels, and the flow of magma beneath Earth’s surface.