NASA Space Place – Doing Science with a Spacecraft’s Signal

Poster’s Note: One of the many under-appreciated aspects of NASA is the extent to which it publishes quality science content for children and Ph.D.’s alike. NASA Space Place has been providing general audience articles for quite some time that are freely available for download and republishing. Your tax dollars help promote science! The following article was provided for reprinting in October, 2012.

By David Doody

2013february2_spaceplaceMariner 2 to Venus, the first interplanetary flight, was launched August 27 fifty years ago. This was a time when scientists were first learning that Venus might not harbor jungles under its thick atmosphere after all. A Russian scientist had discovered that atmosphere during the rare Venus transit of 1761, because of the effects of sunlight from behind.

Mariner 2 proved interplanetary flight was possible, and our ability to take close-up images of other planets would be richly rewarding in scientific return. But it also meant we could use the spacecraft itself as a “light” source, planting it behind an object of our choosing and making direct measurements.

Mariner 4 did the first occultation experiment of this sort when it passed behind Mars as seen from Earth in July 1965. But, instead of visible light from the Sun, this occultation experiment used the spacecraft’s approximately 2-GHz radio signal.

The Mariner 4 experiment revealed Mars’ thin atmosphere. Since then, successful radio science occultation experiments have been conducted at every planet and many large moons. And another one is on schedule to investigate Pluto and its companion Charon, when the New Horizons spacecraft flies by in July 2015. Also, during that flyby, a different kind of radio science experiment will investigate the gravitational field.

The most recent radio science occultation experiment took place September 2, 2012, when the Cassini spacecraft carried its three transmitters behind Saturn. These three different frequencies are all kept precisely “in tune” with one another, based on a reference frequency sent from Earth. Compared to observations of the free space for calibration just before ingress to occultation, the experiment makes it possible to tease out a wide variety of components in Saturn’s ionosphere and atmosphere.

Occultation experiments comprise only one of many categories of radio science experiments. Others include tests of General Relativity, studying the solar corona, mapping gravity fields, determining mass, and more. They all rely on NASA’s Deep Space Network to capture the signals, which are then archived and studied.

Find out more about spacecraft science experiments in “Basics of Space Flight,” a website and book by this author, www2.jpl.nasa.gov/basics. Kids can learn all about NASA’s Deep Space Network by playing the “Uplink-Downlink” game at spaceplace.nasa.gov/dsn-game.

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Caption: In this poster art of Mariner 4, you can see the parabolic reflector atop the spacecraft bus. Like the reflector inside a flashlight, it sends a beam of electromagnetic energy in a particular direction. Credit: NASA/JPL/Corby Waste. Click to see full-size version.

About NASA Space Place

The goal of the NASA Space Place is “to inform, inspire, and involve children in the excitement of science, technology, and space exploration.” More information is available at their website: http://spaceplace.nasa.gov/

Rockland Astronomy Club Hosts NEAF 2013!

Greetings fellow astrophiles!

Barlow Bob (Rockland Astronomy Club member and Solar Observing guru) has sent an official invitation to NEAF 2013, hosted at Rockland Community College in Suffern, NY (a leisurely 4 hour drive from Syracuse). Celebrating its 22nd Anniversary, NEAF is an annual two-day event featuring speakers, solar observing (neafsolar.com), workshops, and vendors, vendors, vendors!

At present, Ryan Goodson (representing New Moon Telescopes) and I are confirmed Syracuse attendees. As NEAF is THE vendor-focused daytime event in our area, it serves as a focal point (no pun intended) for many other local societies to attend and see other amateur astronomers they don’t get to see all year (and it even happens in the daytime, so you actually get to see what your nighttime cohorts look like).

I spent a large portion of NEAF 2011 attending the many astrophotography lectures (a highlight for me being Alan Friedman’s explanation of how he processed the print I later purchased) and accessorizing my own scope (“Ruby”) with Televue eyepieces. NEAF 2012 was a surgical strike with another observer looking to purchase his first high-end refracting telescope (also for imaging). In both cases – and amateur astronomers will recognize this point immediately – it is very difficult to find one location that has on display so much high-end equipment for your (1) direct questioning of vendors, (2) indirect questioning of happy (or not-so-happy) owners, and (3) general viewing pleasure. While we stress the importance of starting observing with nothing more than binoculars and a good star chart, amateur astronomy can become a VERY expensive habit depending on where you want to focus (no pun intended) your observational study. Beyond the educational lectures and workshops, NEAF provides you direct access to a wealth of equipment and information that is hard to collect from web searches alone.

So, if you’re fortunate enough to be collecting a refund on April 15th (or have been smart and saved up all year for a pilgrimage to the Televue booth), consider attending the largest indoor event in East Coast amateur astronomy.

Information about NEAF 2013 can be found at its website: www.rocklandastronomy.com/neaf/index.html.

Show Hours:

* Sat. April 20 – 8:30AM to 6:00PM
* Sun. April 21 – 10:00AM to 6:00PM

Ticket Prices (at the door):

* $20.00 for adults (one day)
* $35.00 for two-day admission ticket
* Under 16 free with parent

Parking:

* FREE parking for more than 1,000 cars and RV’s

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ABOVE: a Dobsonian with everything on it!

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ABOVE: 1/2 of the vendors at NEAF 2012.

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ABOVE: more than just astronomy equipment for sale!

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ABOVE: view of the 2012 Solar Star Party.

Beaver Lake Nature Center Hosts The First Official CNYO Lecture & Observing Session – The Guiding And Wandering Stars

CNYO is delighted to have our first scheduled lecture of the year occur at Beaver Lake Nature Center in Baldwinsville, NY. In a change from the last three lectures hosted at Beaver Lake, there will be NO indoor lecture session. We’ll be running the entire discussion from the central yard in front of the main building, starting the lecture near the setting of the Sun and driving the discussion of Constellations and planets as they appear to our dark-adapting eyes.

The Guiding And Wandering Stars –
Key Northern Constellations And Planet Observation

Thursday, April 25 (Rain Date: Thursday, May 2nd), 7:30 p.m.

Age Range: There are no age requirements, but please be aware (and make children aware) that fragile and expensive observing equipment will be present.

Description:The Constellations have been with us for thousands of years, but you only have a few good clear nights each month to memorize their positions as they slowly move across the sky! This outdoor lecture by the CNY Observers (www.cnyo.org) will briefly describe the history and importance of the Constellations as mythological, agricultural, and navigational guides, then will describe a simple system to begin to learn their relative positions. At the same time, Jupiter and Saturn are on opposite sides of the Southern sky, making excellent targets for binocular and telescope observing.

Admission

$3 per car • $15 per bus
Free for Friends of Beaver Lake

Contact

8477 East Mud Lake Road
Baldwinsville, NY 13027
T: (315) 638-2519
BLNC@ongov.net