NASA has selected a new group of potential astronauts, half of which are women, the space agency announced on Monday, saying that the new “space explorers” will be instrumental in pushing the boundaries of exploration in the solar system.

The group of NASA's newest astronaut trainees includes eight candidates, who were chosen from over 6,000 applicants -- the second largest number of applications NASA has ever received. What has been seen as a cause for celebration is that fact that four of the eight new candidates are women, the highest percentage of female astronaut candidates ever selected for a class.

NASA Selects 8 New Astronauts
NASA selects eight new astronauts. From the top left: Josh A. Cassada, Victor J. Glover, Tyler N. Hague, Christina M. Hammock, Nicole Aunapu Mann, Anne C. McClain, Jessica U. Meir and Andrew R. Morgan. NASA

On the high percentage of women candidates ever selected for a class, NASA's Janet Kavandi, a veteran astronaut and the director of Flight Crew Operations told Voice of America: "That was not by choice or by determination. We never determine how many people of each gender we're going to take, but these were the most qualified people of the ones that we interviewed. They earned every bit of the right to be there."

According to NASA, the eight candidates will be among those who will be the first to be launched from the U.S. on commercial American spacecraft since NASA’s space shuttle program came to an end two years back. The new group of astronauts will receive extensive technical training at space centers and remote locations around the world to prepare for missions to low-Earth orbit, an asteroid and Mars.

“They're excited about the science we are doing on the International Space Station and our plan to launch from the U.S. soil to there on spacecraft built by American companies. And they are ready to help lead the first human mission to an asteroid and then on to Mars,” NASA Administrator Charles Bolden said.

The four female astronaut candidates include a fighter pilot, a helicopter pilot, a National Oceanic and Atmospheric Administration, or NOAA, station chief and an assistant professor of Anesthesia at Harvard Medical School.

NASA said the new astronaut candidates will begin training at NASA's Johnson Space Center in Houston in August. The candidates from the Army, Navy, Air Force and Marines will be getting their military salaries as usual, while the civilians can earn between $64,724 and $141,715 a year, based on their education and experience.

The new candidates are likely to lead the first human mission to an asteroid in the 2020s, and then Mars. Also, they may be among the first to fly to the space station aboard commercial spacecraft launched from the U.S. as Russia ferries the astronauts at present, the Associated Press reported.

“These new space explorers asked to join NASA because they know we are doing big, bold things here -- developing missions to go farther into space than ever before,” Bolden said in a statement.

Take a look at the profiles of the women candidates here:

Christina M. Hammock: Hammock, 34, is the station chief at NOAA in American Samoa. She is from Jacksonville, N.C. and holds undergraduate and graduate degrees from North Carolina State University, Raleigh.

Nicole Aunapu Mann: Mann is a major in the Marine Corps and currently serves as an integrated product team lead at the U.S. Naval Air Station, Patuxent River in Maryland. She is 35 years old and a graduate of the U.S. Naval Academy and Stanford University.

Anne C. McClain: McClain, 34, is a major in the U.S. Army. She is an OH-58 helicopter pilot, and a recent graduate of the U.S. Naval Test Pilot School at Naval Air Station, Patuxent River. McClain has listed her hometown as Spokane, Wash.

Jessica U. Meir: Meir, a 35-year-old assistant professor of Anesthesia at Harvard Medical School, holds a Ph.D. from Scripps Institution of Oceanography at UCSD. Meir also has an advanced degree from the International Space University. She was an aquanaut in the NASA Extreme Environment Mission Operations, or NEEMO, program and flew on NASA’s parabolic flight aircraft as part of her study of how microgravity affects the human body.

The other four male candidates include a former naval aviator, an F/A-18 pilot, a graduate of the U.S. Air Force Academy and a graduate of the U.S. Military Academy, who has experience as an emergency physician and flight surgeon for the Army.

Here are the brief profiles:

Josh A. Cassada: Cassada, 39, is a former naval aviator who holds an undergraduate degree from Albion College, and advanced degrees from the University of Rochester, N.Y. Cassada is a physicist by training and hails from White Bear Lake, Minn. At present, he serves as the co-founder and Chief Technology Officer for Quantum Opus.

Victor J. Glover: 37-year-old Glover is a Lt. Commander in the U.S. Navy and hails from Pomona, Calif., and Prosper, Texas. He is an F/A-18 pilot and graduate of the U.S. Air Force Test Pilot School, Edwards, Calif. Glover holds degrees from California Polytechnic State University, San Luis Obispo, Calif.; Air University and the Naval Postgraduate School, Monterey, Calif. Currently, he serves as a Navy Legislative Fellow in the U.S. Congress.

Tyler N. (Nick) Hague: Hague, 37, is a Lt. Colonel in the U.S. Air Force and hails from Hoxie, Kan. He is a graduate of the U.S. Air Force Academy, Colorado Springs, Colo.; Massachusetts Institute of Technology, Cambridge, Mass. and the U.S. Air Force Test Pilot School, Edwards, Calif. Hague supports the Department of Defense as deputy chief of the joint improvised explosive device defeat organization.

Andrew R. Morgan: Morgan, 37, is a Major in the U.S. Army and has experience as an emergency physician and flight surgeon for the Army special operations community. Morgan is a graduate of the U.S. Military Academy at West Point, and earned a doctorate in medicine from the Uniformed Services University of the Health Sciences, Bethesda, Md. He hails from New Castle, Pa. and is currently completing a sports medicine fellowship.