April 5, 2020

30.03.11: Welcome to Mercury!

A new resident has taken up orbit around the solar system’s inner most-world. Fresh from orbital insertion earlier this month, NASA’s Messenger spacecraft opened its eyes and began relaying images that have been a web sensation over the past 24 hours. Messenger is currently 6 light minutes from Earth; its looping orbit takes it from a periapsis of about 200 km to apsis at 1,500 km.

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A Messier Marathon.

Spring is deep sky season. As the weather becomes more temperate and the daylight/nighttime balance sits roughly equal worldwide, telescopes at star parties begin to sprout up like springtime daffodils. Now is the time to nab that obscure cluster, or attempt to spy that faint planetary nebula. We here at Astroguyz always try to spot one new object every observing session… but have you ever tried to see all the Messier objects… in one night?

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19.01.11: A Valentine’s Day Flyby.

One down, and one to go… next month, NASA intends to perform another first; the first follow up flyby of a cometary nucleus. The spacecraft is Stardust, and the comet is Tempel 1. Today’s mission briefing gave a glimpse of the action that is in store. Launched in February, 1999 Stardust has performed an array of firsts, including the first sample return from Comet Wild 2 in 2004, and one of the highest re-entry velocities ever attempted during its successful sample return in 2006.

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02.06.10: Dawn-A New Way to Explore the Solar System.

An asteroid-bound spacecraft is also blazing a trail for technologies of the future. Dawn, NASA’s asteroid rendezvous mission blasted off from Cape Canaveral September 27th, 2007 enroute to explore the asteroids Ceres and Vesta starting next year. But unlike previous solar system missions, Dawn is able to do something that most interplanetary spacecraft can’t; change trajectories. Older traditional chemical rockets rely on their initial imparted thrust to get them on their way, but once that’s applied, the course is set. Beyond gravitational sling-shotting, little can be done to adjust their overall orbital paths, and you can’t park in orbit and visit interesting bodies, a major drawback. Dawn instead utilizes ion thrust engines. These provide a low thrust over a long period of time, rather than a chemical rockets’ high thrust in a short period of time. Although it requires Dawn a lengthy period to build up speed, its Xenon-solar powered drives ultimately win the race where specific impulse is concerned. This also enables it to carry a relatively light load of propellant. In fact, Dawn carries enough Xenon propellant for over 5 years of use. First proposed by none other than American rocket pioneer Robert Goddard in 1906, Ion based propulsion was first tested in 1959 at NASA, and utilized in the first  spacecraft aboard SERT-1 in 1964, and then more famously aboard Deep Space 1 in 1998. Many science fiction fans will remember the reference to ion drives in the original Star Trek episode “Spock’s Brain,” and the lineage can no doubt be traced further back in pulp Sci-Fi literature. Other spacecraft, such as the heroic Hayabusa returning to Earth next week and the proposed LISA Pathfinder, also utilize ion technology. Ion drive is well suited for asteroid exploration due to their low gravity fields, but in time missions bound for the major planets and moons could sport ion drives, as well. What Dawn will find as it nears the two asteroids is waiting to be seen; Vesta is a rocky terrestrial-type asteroid which may resemble early proto-solar material that formed rocky worlds like the Earth, and Ceres may even harbor a Europa-style environment, complete with ice enshrouded oceans! Dawn is scheduled to orbit Vesta for a year starting in July, 2011, and arrive at Ceres in February 2015. Perhaps, history will record that it was the ion-drive that truly opened up space exploration, and was ultimately how the solar system was won!

Review: How to Build a Habitable Planet by James Kasting.

Some years ago, a book entitled Rare Earth was published amid much controversy. The central thesis of this work was that events that led to the eventual habitability and diversity of life and intelligence on Earth were so improbable, as be near to impossible to replicate elsewhere in our galaxy. The book marked a sort of change in thinking in the realm of exobiology, one from “intelligent civilizations are everywhere” championed by the late Carl Sagan to the concept that we may be the only ones, if not the first.

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27.01.10: As Titan Turns.

Think that this winter is brutal here on Earth? As February is about to set in, we here at Astroguyz invite you to contemplate the seasons on Titan, the largest moon of Saturn. At over 3,000 miles in diameter, Titan is larger than some planets, and possesses an opaque hydro carbon smog veil of an atmosphere. There, a balmy summer day might reach 290°F on the thermometer, and sunshine is a dim murk at best. Scientists have recently found out that this seemingly dismal world is in fact a dynamic place, and a world well worth further scrutiny. The Cassini spacescraft has already conducted fly-bys of the mysterious moon since its orbital insertion in 2004, and even deposited the Huygens probe, which still stands as the most distant soft landing of a manned spacecraft ever made. Now, scientists Emily Schaller of the University of Hawaii and Henry Roe of the Lowell Observatory have been successful in tracking storms in Titan’s turbulent atmosphere. Like Earth, Titan is one of the very few rocky worlds in the solar system that possesses a hydrological cycle and weather. On Titan, however, it rains liquid methane and pools of ammonia dot the surface of this bizarre world. Using the 3-meter Infra-red Telescope Facility, Schaller and Roe monitored Titan 138 nights over 2.2 years in the 2.1 micron range, using the much more sensitive Gemini North telescope also on Mauna Kea for follow up observations when things started to look interesting. Titan is a tough target to image; at its best, it presents a disk no more than 0.8” in diameter. The 2008 storm pictured about demonstrates that Titan is indeed a changing world, one that deserves further examination. Cassini has already performed another flyby of Titan earlier this month on January 12th as part of its mission extension.

Review: The Quiet War by Paul McAuley.

One all-pervasive theme that waxes and wanes in the sci-fi genre more than warrior-maidens’ hemlines is the role of warfare in the future of humanity. This concept swings from the space war operas spawned in the pulp era of the 30-40s to the doctrine of a “shinny happy future” as an antidote to the Cold War era. War seems to be on the upswing again, perhaps as an extension of the human condition and the impact of the current Global War on Terrorism on the popular psyche. The Quiet War by Paul McAuley and out this month by Pyr Books takes the concept of warfare out into the Solar System of the semi- near future. [Read more...]