Look, up in the sky! Moon Occults Mars, 2020-02-18

Occultation of Mars by the Moon, 2003-07-17.
Original photo © 2003 Andrew Chaikin.

On the morning of February 18th, 2020, observers in most of North America will be able to see the waning crescent Moon pass in front of (occult) the planet Mars.  The photo at the right, taken by Andrew Chaikin during the 2003 lunar occultation of Mars, is more dramatic than this event will appear through a telescope.  In the 2003 occultation, Mars was just 0.48 astronomical units (AU) from the Earth, while this time Mars will be at distance of 1.81 AU, 3.8 times farther away and correspondingly smaller and dimmer.  Still, Mars will shine at magnitude 1.2, one of the brightest “stars” in the sky, and its reddish hue will stand out against the colourless Moon.

Lunar occultation of Mars, 2020-02-18This map shows the visibility of the occultation.  The occultation will be visible in the area delimited by the cyan shape at the top and the multicoloured curve at the bottom.  The event will thus be visible in most of North America (except for Alaska and the far north of Canada), Central America, and the Caribbean.  In the area of the loop at the top left, covering part of the American northwest and western Canada, the Moon will rise with the occultation already in progress, but observers will be able to see Mars emerge from behind the Moon’s dark limb at its conclusion.... [Read More]



Lawrence Meyers, a writer unknown to me, took a shot at SpaceX, along with other enterprises operating in murky financial territory such as Uber and Tesla.  I took umbrage at his snark about SpaceX, but care less about the other targets of his moralistic ire.  To me, SpaceX is a prime motivator for my desire to live, not forever, but exceptionally long enough to see the inspiring fruits of all those engineers’ labors.  I don’t comment online much, but Townhall is pretty mellow, so I left the following comment on this article: https://townhall.com/columnists/lawrencemeyers/2019/11/23/corrupt-values-will-eventually-implode-silicon-valley-n2556696

“Tesla is a toy manufacturer, but SpaceX has serious accomplishments and is on track with its huge satellite program for space-based internet and with its stupendous rocket engineering. Tesla is in a niche market for a simple commodity, but SpaceX is blasting our path to interplanetary exploration, and is inspiring. Tesla, Uber and all other such mundane enterprises are in the bailiwick of “a fool and his money are soon parted” territory. No tears or outrage from me. On the other hand Falcon Heavy’s maiden flight gave me goosebumps and a lump in my throat. Let all those who maunder on about SpaceX try flying to the Moon before they carp about the process.”  Who else loves SpaceX here?


Book Review: Public Loneliness

“Public Loneliness” by Gerald BrennanThis is the second book in the author’s “Altered Space” series of alternative histories of the cold war space race. Each stand-alone story explores a space mission which did not take place, but could have, given the technology and political circumstances at the time. The first, Zero Phase, asks what might have happened had Apollo 13’s service module oxygen tank waited to explode until after the lunar module had landed on the Moon. The third, Island of Clouds, tells the story of a Venus fly-by mission using Apollo-derived hardware in 1972.

The present short book (120 pages in paperback edition) is the tale of a Soviet circumlunar mission piloted by Yuri Gagarin in October 1967, to celebrate the 50th anniversary of the Bolshevik revolution and the tenth anniversary of the launch of Sputnik. As with all of the Altered Space stories, this could have happened: in the 1960s, the Soviet Union had two manned lunar programmes, each using entirely different hardware. The lunar landing project was based on the N1 rocket, a modified Soyuz spacecraft called the 7K-LOK, and the LK one-man lunar lander. The Zond project aimed at a manned lunar fly-by mission (the spacecraft would loop around the Moon and return to Earth on a “free return trajectory” without entering lunar orbit). Zond missions would launch on the Proton booster with a crew of one or two cosmonauts flying around the Moon in a spacecraft designated Soyuz 7K-L1, which was stripped down by removal of the orbital module (forcing the crew to endure the entire trip in the cramped launch/descent module) and equipped for the lunar mission by the addition of a high gain antenna, navigation system, and a heat shield capable of handling the velocity of entry from a lunar mission.... [Read More]


Sixty Years Ago: First to the Moon

Luna 2, Soviet lunar impact spacecraftLast July, we celebrated Apollo 11, which performed the first manned landing on the Moon on July 20th, 1969.  This month marks the sixtieth anniversary of the first landing on the Moon, and the first spacecraft from Earth to touch another body in the solar system.

On September 12th, 1959, the Soviet Union launched Luna 2 toward the Moon.  This was the fifth Soviet attempt to launch a spacecraft to impact the Moon.  The first three failed during launch.  The fourth, Luna 1, missed the Moon by 5965 km and went into orbit around the Sun.  Luna 2, an identical spacecraft, was launched on a direct trajectory to the Moon by a booster designated 8K72, which used the R-7 ballistic missile (the same type which launched Sputnik) to launch an upper stage called Block E, which boosted the spacecraft toward the Moon.  The launch used a direct trajectory, Jules Verne-style, which did not enter either Earth or Moon orbit, but instead travelled directly from launch to impact on the lunar surface.... [Read More]


Vikram: India to the Moon

Indian Chandrayaan/Vikram lunar landerYou may recall that back on 2019-04-11 we covered the attempt by Israeli non-profit company SpaceIL to land its Beresheet spacecraft on the Moon.  The landing occurred, but with an impact velocity much greater than the hoped-for soft touchdown, dashing Israel’s hope to be fourth country to soft land on the Moon and, incidentally, thwarting plans for the tardigrade conquest of Earth’s natural satellite.

Now, it’s India’s turn.  Today, on 2019-09-06, India’s Vikram lander is scheduled to attempt a soft landing on the Moon between craters Manzinus C and Simpelius N near 70.9° south latitude, the southernmost point of any Moon landing.  The lander is part of the Chandrayaan-2 mission, which was launched on 2019-07-22 by the Indian Space Research Organisation from the Satish Dhawan Space Centre.  If the landing is successful, the lander will deliver a solar-powered rover, Pragyan, to the surface.  The main Chandrayaan spacecraft will study the Moon from a high-inclination 100 km orbit; it released the lander on Monday at 07:45 UTC.... [Read More]


This Week’s Book Review – Final Frontier

I write a weekly book review for the Daily News of Galveston County. (It is not the biggest daily newspaper in Texas, but it is the oldest.) After my review appears on Sunday, I post the previous week’s review here on Sunday.

Book Review

The Moon can make for entertaining science fiction

By MARK LARDAS... [Read More]


Saturday Night Science: The Case for Space

“The Case for Space” by Robert ZubrinFifty years ago, with the successful landing of Apollo 11 on the Moon, it appeared that the road to the expansion of human activity from its cradle on Earth into the immensely larger arena of the solar system was open. The infrastructure built for Project Apollo, including that in the original 1963 development plan for the Merritt Island area could support Saturn V launches every two weeks. Equipped with nuclear-powered upper stages (under active development by Project NERVA, and accommodated in plans for a Nuclear Assembly Building near the Vehicle Assembly Building), the launchers and support facilities were more than adequate to support construction of a large space station in Earth orbit, a permanently-occupied base on the Moon, exploration of near-Earth asteroids, and manned landings on Mars in the 1980s.

But this was not to be. Those envisioning this optimistic future fundamentally misunderstood the motivation for Project Apollo. It was not about, and never was about, opening the space frontier. Instead, it was a battle for prestige in the Cold War and, once won (indeed, well before the Moon landing), the budget necessary to support such an extravagant program (which threw away skyscraper-sized rockets with every launch), began to evaporate. NASA was ready to do the Buck Rogers stuff, but Washington wasn’t about to come up with the bucks to pay for it. In 1965 and 1966, the NASA budget peaked at over 4% of all federal government spending. By calendar year 1969, when Apollo 11 landed on the Moon, it had already fallen to 2.31% of the federal budget, and with relatively small year to year variations, has settled at around one half of one percent of the federal budget in recent years. Apart from a small band of space enthusiasts, there is no public clamour for increasing NASA’s budget (which is consistently over-estimated by the public as a much larger fraction of federal spending than it actually receives), and there is no prospect for a political consensus emerging to fund an increase.... [Read More]


This Week’s Book Review – Moon Tracks

I write a weekly book review for the Daily News of Galveston County. (It is not the biggest daily newspaper in Texas, but it is the oldest.) My review normally appears Wednesdays. When it appears, I post the review here on the following Sunday.... [Read More]


Beresheet: Israel to the Moon

The Beresheet spacecraft, built by Israeli non-profit company SpaceIL, is scheduled to land on the Moon today.  Landing operations are expected to begin around 19:00 UTC (you can see a UTC clock in the right side of the title bar of this site).  Landing is planned for a site in the north of Mare Serenetatis, on the north-east part of the near side of the Moon, within a 15 km area known to have little rubble or rugged terrain.  Here is a preview of the landing process from SpaceIL.

... [Read More]


A Meteor Hits the Moon During the Eclipse

Meteor impact on the Moon, 2019-01-21During the recent lunar eclipse (the date on which it occurred depends upon your time zone: mid-eclipse was at 05:12 UTC on 2019-01-21, while the eclipse occurred on the evening of January 20th in western hemisphere time zones) several amateur astronomers capturing the eclipse on video observed a flash of light, just a single video frame, near the limb of the eclipsed Moon just at the beginning of the umbral phase.

The fact that three observers in different locations have so far reported the same flash excludes other explanations such as a reflection off an Earth satellite or a “point meteor” burning up in the Earth’s atmosphere on a trajectory pointed directly at the observer.... [Read More]


Chang’e 4 (嫦娥四号) Lands on the Far Side of the Moon

Chang'e 4 landing site on the far side of the MoonAt 02:26 UTC on 2019-01-03, the Chinese Chang’e 4 (嫦娥四号) soft lander and rover touched down in the Von Kármán crater on the far side of the Moon.  This is the first soft landing on the far side of the Moon, which is never visible from the Earth.  Here is a video including animation of the landing and actual images captured during the descent and of the surface after landing.

... [Read More]


TOTD 2018-03-30: The Moon, Up Close and Personal

Since 1994, Fourmilab’s Earth and Moon Viewer has provided custom views of the Earth and Moon from a variety of viewpoints, using imagery databases which have evolved over the years from primitive images to gigabyte-scale mosaics collected by spacecraft.  Views were originally restricted to the Earth, but fifteen years ago, in April 2003, the ability to view the Moon was added, using the global imagery collected by the Clementine orbiter.  These data were wonderful for the time, providing full-globe topography and albedo databases with a resolution of 1440×720 pixels.  This allowed viewing the Moon as a whole or modest zooms into localities, but when you zoomed in close the results were…disappointing.  Here is the crater Copernicus viewed from an altitude of 10 km using the Clementine data.

Moon, Copernicus crater, 10 km altitude, Clementine data... [Read More]