Just Passing By

Because the amount of energy necessary for an interplanetary flight is available from practical launch vehicles, spacecraft often use a planet’s gravity to provide some of the energy needed for final trajectories. Properly executed, one or more gravity assist flybys can be enough to change a spacecraft’s speed and direction so it can enter orbit around another world or fly off into the Kuiper Belt or even interstellar space.

This view of Earth was captured in 2007 on the second of three Earth flybys made by ESA’s comet-chasing Rosetta spacecraft on its ten year journey to Comet 67P/Churyumov-Gerasimenko.

Image Credit: ESA

Fermi’s Spriagraph

Fermi's Motion Produces a Study in SpirographThe Fermi Gamma-ray Space Telescope orbits the Earth every 95 minutes, it’s scans building up increasingly more complex views of the universe with every circuit. The image above was put together from eight frames from a movie showing over 4 years’ position and exposure data recorded by Fermi‘s Large Area Telescope (LAT) into a single snapshot. The pattern reflects the various motions of the spacecraft, including its orbit around Earth, the precession of its orbital plane, and the manner in which the LAT nods north and south on alternate orbits.

The LAT sweeps across the entire sky every three hours, capturing the highest-energy form of light—gamma rays—from sources across the universe. Those sources range from supermassive black holes billions of light-years away to objects in our own galaxy, such as X-ray binaries, supernova remnants, and pulsars.

Image Credit: NASA/DoE

From the Far Side

Four weeks after the Chinese Chang’e 4 spacecraft landed on the far side of the Moon, the Lunar Reconnaissance Orbiter approached the landing site from the east, rolled 70 degrees to the west, and snapped this view of Chang’e 4. The large crater in the center (just right and below arrows) is about 440 m across.

Image Credit: NASA / GSFC / ASU

Dust Survives a Supernova

This artist’s concept illustrates Supernova 1987A as the powerful blast wave passes through its outer ring and destroys most of its dust, before the dust re-forms or grows rapidly. Observations by SOFIA, a Boeing 747SP jetliner modified to carry a 106-inch diameter telescope, reveal that such dust — which makes up the building blocks of stars and planets — can re-form or grow immediately after the catastrophic damage caused by the supernova’s blast wave.

Video Credit: NASA