Category Archives: Space Exploration

We Are Going

John F. Lindner April 29, 2023 9:08 PM

After half a century confined to low-Earth orbit, and as soon as late next year, humans will once again leave Earth and voyage to Moon. The reality of this exciting adventure crystallized earlier this month when NASA announced the diverse … Continue reading →

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Triple EVA

John F. Lindner February 16, 2023 11:15 PM

Since the mid 1960s, all space walks or extra-vehicular activities (EVAs) have involved just one or two astronauts — except once. In May 1992, on the STS-49 mission, the crew of the space shuttle Endeavour was attempting to rescue a stranded communications … Continue reading →

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Artemis Is the Sister of Apollo

John F. Lindner November 16, 2022 11:40 PM

I stayed up late last night and early this morning to watch the successful uncrewed launch of Artemis 1. In Greek tradition, Artemis was the twin sister of Apollo, and the Artemis program hopes to return humans — including the … Continue reading →

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Zero-G Indicator

John F. Lindner October 11, 2022 2:12 PM

When Crew 5 rocketed to orbit last week aboard the SpaceX Dragon “Endurance” bound for the International Space Station, I was curious to see their zero-gravity indicator. A tradition SpaceX crews have adopted from Russian cosmonauts, the zero-g indicator is usually a … Continue reading →

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For the dinosaurs!

John F. Lindner September 26, 2022 8:26 PM

The dinosaurs didn’t have a space program, but we do. I just watched live the first kinetic-impact asteroid-redirection test as NASA’s Double Asteroid Redirection Test spacecraft collided with the asteroid-moon Dimorphos of the asteroid Didymos. Below is the last image … Continue reading →

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GRAVITY and Gravity

John F. Lindner June 23, 2022 9:34 AM

In Alfonso Cuarón‘s Oscar-winning 2013 movie GRAVITY, actress Sandra Bullock‘s Dr. Ryan Stone makes an emergency entrance into an abruptly abandoned International Space Station. This month, European Space Agency astronaut Samantha Cristoforetti recreated this scene onboard the space station, as in … Continue reading →

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Diffraction Limited

John F. Lindner March 17, 2022 11:41 AM

Yesterday, Webb optical telescope element manager Lee Feinberg said “We made the right telescope” while reporting that its focus has reached the  diffraction limit of 0.7 arcseconds at the infrared wavelength of 2 microns. (For comparison, from Earth, Luna subtends … Continue reading →

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Halo Orbit

John F. Lindner February 7, 2022 5:43 PM

The Webb telescope has fully deployed and arrived at its halo orbit about the second Earth-Sun Lagrange point. But how can it orbit an empty point in space? In the accompanying animated sequence of inertial space diagrams, a star (red) … Continue reading →

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Merlin & Raptor

John F. Lindner January 1, 2022 10:21 PM

The turbopump is the heart of most liquid-fueled rocket engines. Gas generator engines tap off and burn a little propellant to drive a turbine, which turns a centrifugal pump, which rapidly pushes the fuel and oxidizer to the combustion chamber, after the cryogenic … Continue reading →

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Astronomy Christmas Gift

John F. Lindner December 25, 2021 5:11 PM

I awoke early this Christmas morning to watch the successful launch of the James Webb Space Telescope. I remember the genesis of the telescope a quarter of a century ago when it was called the Next Generation Space Telescope. (The … Continue reading →

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