The Martian ice cap is like a cake with every layer telling a story. In this case, the story is one of climate change on Mars. http://www.nasa.gov/sites/default/files/thumbnails/image/pia23740.jpg

When Apollo 9 in March 1969 human spaceflight, it was the second crewed mission and the countdown to Apollo 11. http://www.nasa.gov/sites/default/files/thumbnails/image/20190301_as09-21-3206.jpg

Michun North is a program analyst, who helps manage finances for the Commercial Crew Program. http://www.nasa.gov/sites/default/files/thumbnails/image/michun_north_with_astronaut_suit_0.jpg

Expedition 63 crewmembers Chris Cassidy of NASA (left) and Anatoly Ivanishin (center) and Ivan Vagner of Roscosmos (right) pose for pictures in front of a Soyuz trainer. http://www.nasa.gov/sites/default/files/thumbnails/image/jsc2020e016220_0.jpg

With the USS John P. Murtha (LPD 26) in the distance, helicopters from the HSC-23 squadron fly by a test version of an Orion capsule during Underway Recover y Test-8 in the Pacific Ocean. http://www.nasa.gov/sites/default/files/thumbnails/image/urt_8.jpg

An alligator lurks in a marshy waterway at NASA's Kennedy Space Center in Florida. The center shares a border with the Merritt Island National Wildlife Refuge. http://www.nasa.gov/sites/default/files/thumbnails/image/alligator_in_waterway.jpg

Former astronaut Al Worden, command module pilot on the Apollo 15 lunar landing, passed away March 18, 2020, in Texas.​ http://www.nasa.gov/sites/default/files/thumbnails/image/71-h-1253.jpg

Michelle Lynde is an aerospace engineer who conducts aerodynamic analysis of configurations using Computational Fluid Dynamics tools, wind tunnel experiments and flight tests. http://www.nasa.gov/sites/default/files/thumbnails/image/lrc-2018-b701_p-00869.jpg

The central region of our galaxy, the Milky Way, contains an exotic collection of objects. http://www.nasa.gov/sites/default/files/thumbnails/image/milkyway.jpg

Christina Koch handles media bags that enable the manufacturing of organ-like tissues using the BioFabrication Facility (BFF), a 3-D biological printer on the International Space Station. http://www.nasa.gov/sites/default/files/thumbnails/image/iss061e093848_0.jpg

NASA’s new three-dimensional portrait of methane concentrations shows the world’s second largest contributor to greenhouse warming. http://www.nasa.gov/sites/default/files/thumbnails/image/fullglobe_asia_nobar.jpg

This photograph shows ripples in the surface of Denman Glacier in East Antarctica that throw shadows against the ice. http://www.nasa.gov/sites/default/files/thumbnails/image/denman20200325-nasa.jpg

Located about 21 million light-years from our galaxy in the constellation Canes Venatici, NGC 4618 has a diameter of about one-third that of our Milky Way. Together with its neighbor, NGC 4625, it forms an interacting galaxy pair, which means that the two galaxies are close enough to influence each other gravitationally. http://www.nasa.gov/sites/default/files/thumbnails/image/potw2012a.jpg

Today is National Doctors' Day! http://www.nasa.gov/sites/default/files/thumbnails/image/1472px-mae-jemison_1.jpg

In March 2017, Peggy Whitson broke the then-spacewalking record for female astronauts. http://www.nasa.gov/sites/default/files/thumbnails/image/iss050e028908_0.jpg

Appearing as strings of orange dots, the brightest sets of dots belong to asteroids Klotho and Lina. Both orbit out in the main asteroid belt between Mars and Jupiter. http://www.nasa.gov/sites/default/files/thumbnails/image/pia23589.jpg

This 2010 image from the Herschel Space Observatory shows dust clouds associated with the Rosette Nebula, a stellar nursery about 5,000 light-years from Earth in the Monoceros, or Unicorn, constellation. http://www.nasa.gov/sites/default/files/thumbnails/image/rosette_herschel_hi.jpg

This remarkable spiral galaxy, known as NGC 4651, may look serene and peaceful as it swirls in the vast, silent emptiness of space, but don’t be fooled — it keeps a violent secret. http://www.nasa.gov/sites/default/files/thumbnails/image/potw2013a.jpg

In this Hubble Space Telescope image, researchers has revisited one of Hubble's most iconic and popular images: the Eagle Nebula’s Pillars of Creation. http://www.nasa.gov/sites/default/files/thumbnails/image/heic1501b_0.jpg

Aboard the International Space Station, NASA astronaut Jessica Meir conducts cardiac research inside the Life Sciences Glovebox. http://www.nasa.gov/sites/default/files/thumbnails/image/iss062e115355_0.jpg