Almost 3,000 operational spacecraft orbit our Earth. This number is growing constantly, thanks to cheaper materials and smaller satellites.

Having this many satellites in orbit can create problems, including space junk and the way they change our view of the night sky. But satellites provide a vital service.

Many people are familiar with GPS, which helps us navigate. Some may know satellites provide crucial data for our weather forecasts. But satellites affect our lives in many different ways—and some of these may surprise you.

1. Spending money

Whether you pay for your morning coffee using a contactless payment, Google Pay, or even with cash withdrawn from an ATM, none of it would be possible without satellites. In fact, all financial transactions—from multimillion pound stock market transactions, to your monthly Netflix subscription – rely on satellite location and timing services for security.

Global navigation satellite systems orbit about 20,000km above the surface of the Earth and continually communicate with phones and computers to tell them precisely where they are and what time it is.

A new study out this month suggests that Jupiter's Trojan asteroids may be more peculiar than previously thought. The Trojan asteroids are rocky objects which orbit the sun just ahead of and just behind the gas giant, in gravitational sweet spots known as Lagrange points. The swarm ahead of Jupiter, known as the L4 (Greek) group, is slightly larger than the L5 (Trojan) swarm behind, but until now, astronomers believed that there was otherwise little differentiation between the two swarms. The paper released this month appears to change that.

The research team, using data from the Asteroid Terrestrial-impact Last Alert System (ATLAS) based in Hawaii, has discovered unexpected variations in the shape of the Trojans. This new study suggests that objects in the L4 population are actually more elongated than those in the L5 population, on average.

Why does this matter? Well, the difference "may imply a different collisional evolution within each cloud," the paper suggests. The L4 swarm's larger population means objects within it have had had more opportunities to collide with one another. As one Trojan slams into another, larger objects are worn down or broken into smaller pieces.

Millie Hughes-Fulford, a trailblazing astronaut and scientist who became the first female payload specialist to fly in space for NASA, died following a yearslong battle with cancer, her family said. She was 75.

Hughes-Fulford was selected by NASA for its astronaut program in 1983 and five years later, in June 1991, spent nine days in orbit on the shuttle Columbia, conducting experiments on the effect of space travel on humans as part of the agency's first mission dedicated to biomedical studies, STS-40. She and her crew mates circled the Earth 146 times.

The research shaped the rest of her career and upon her return she established the Hughes-Fulford Laboratory at the San Francisco VA Healthcare System, which worked to understand the mechanisms that regulate cell growth in mammals.

"She came back to her world as a scientist and carried this experience of having flown in space and that became a unique filter through which she passed all of her scientific work," said Dr. Mike Barratt, a NASA flight surgeon assigned to Columbia, told the San Francisco Chronicle.

The laboratory was active right up through Hughes-Fulford's own seven-year battle with lymphoma. She died Feb. 2, at her San Francisco home. Her death was confirmed by her granddaughter, Kira Herzog of Mill Valle.

A spacecraft from the United Arab Emirates was set to swing into orbit around Mars in the Arab world's first interplanetary mission Tuesday, the first of three robotic explorers arriving at the red planet over the next week and a half.

The orbiter, called Amal, Arabic for Hope, traveled 300 million miles in nearly seven months to get to Mars with the goal of mapping its atmosphere throughout each season.

A combination orbiter and lander from China is close behind, scheduled to reach the planet on Wednesday. It will circle Mars until the rover separates and attempts to land on the surface in May to look for signs of ancient life.

A rover from the U.S.