Spacewalking astronauts launched a tiny Peruvian research satellite Monday off the International Space Station, setting it loose on a mission to observe Earth.

Expedition 40 Flight spacewalkers Alexander Skvortsov and Oleg Artemyev marked the official start of their planned 6.5-hour spacewalk when they stepped out of the International Space Station (ISS) at 10:02 a.m. EDT on Monday.

NASA Television is providing live coverage of the spacewalk.

The four-inch, two-pound nanosatellite - named Chasqui after Incan messengers - sailed 260 miles above Earth and as planned, cleared the vicinity of the ISS.

"One, two, three," someone called out in Russian as Artemiev let go of the satellite, The Associated Press (AP) reported.

The satellite was designed to take pictures of the Earth with a pair of cameras, which will then be transmitted to a ground station, as well as measure temperature and pressure. The project is part of an effort by the National University of Engineering in Peru to gain experience in satellite, communication and information technologies, according to a NASA news release. A Russian cargo ship delivered the device earlier this year.

Skvortsov and Artemyev will also install the EXPOSE-R2 experiment package - a European Space Agency-sponsored suite of experiments - on a section of the Zvezda service module, a communication systems antenna they set up during their first spacewalk on June 19.

"The package includes two astrobiology studies that will investigate biomaterials and extremophiles - organisms that are tolerant of environmental extremes. Results from these experiments may contribute to life-detection strategies for future robotic exploration of Mars," NASA wrote in the news release.

In addition, the spacewalkers are slated to retrieve several science packages designed to subject a variety of materials to the harsh environment of space.

US spacewalks, however, are currently on hold due to issues with the batteries built into the astronauts' spacesuits. NASA hoped to resume spacewalks this month after a yearlong investigation into the matter, but delayed the activity until autumn when replacement batteries can be delivered to the space station, the AP reported.