APOD: Atlas V Launches TDRS-K (2013 Feb 01)

APOD Robot · Post by **APOD Robot** » Fri Feb 01, 2013 5:06 am

Atlas V Launches TDRS-K

Explanation: Beyond a fertile field of satellite communication antennas at Kennedy Space Center, an Atlas V rocket streaks into orbit in this long exposure photograph. In the thoughtfully composed image recorded on the evening of January 30, the antennas in the foreground bring to mind the rocket's payload, a Tracking and Data Relay Satellite (TDRS; sounds like TEE-dress). This TDRS-K is the first in a next-generation series adding to the constellation of NASA's communication satellites. Operating from geosynchronous orbit 22,300 miles (36,000 kilometers) above planet Earth, the network of TDRS satellites relays communications, data, and commands between spacecraft and ground stations. Formerly the TDRS network provided communications for space shuttle missions. In fact, many TDRS satellites were ferried as far as low Earth orbit on space shuttles. The TDRS network continues to support major spacecraft like the International Space Station, the Hubble Space Telescope, and the Fermi Gamma-ray Space Telescope.

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Beyond · Post by **Beyond** » Fri Feb 01, 2013 5:41 am

LOOK! up in the sky, it's a... it's a... it's a TEE-dress

henrystar · Post by **henrystar** » Fri Feb 01, 2013 10:25 am

"The TDRS network continues to support major spacecraft like the International Space Station, the Hubble Space Telescope, and the Fermi Gamma-ray Space Telescope." That, I think, is not what is meant. What is meant is, "The TDRS network continues to support major spacecraft such as the International Space Station, the Hubble Space Telescope, and the Fermi Gamma-ray Space Telescope. In other words, TDRS actually supports HST, not just spacecraft that happen to be similar to HST; HST itself is supported.

Boomer12k · Post by **Boomer12k** » Fri Feb 01, 2013 11:24 am

Nice picture, interesting perspective.

:---[===] *

neufer · Post by **neufer** » Fri Feb 01, 2013 4:30 pm

henrystar wrote:
"The TDRS network continues to support major spacecraft like the International Space Station, the Hubble Space Telescope, and the Fermi Gamma-ray Space Telescope."

That, I think, is not what is meant.

What is meant is, "The TDRS network continues to support major spacecraft such as the International Space Station, the Hubble Space Telescope, and the Fermi Gamma-ray Space Telescope.

In other words, TDRS actually supports HST, not just spacecraft that happen to be similar to HST; HST itself is supported.

<<Exempli gratia, "for the sake of example" (usually shortened in English to "for example"),
is commonly abbreviated "e.g."; in this usage it is sometimes followed by a comma, depending on style.>>

http://www.urbandictionary.com/define.php?term=egg%20on%20your%20face wrote:
<<e.g.g on your face: To be extremely embarrassed.

Usually the embarassment is the result of one's own actions.

Not sure of the origin, but it may come from when clowns are at a circus and they have eggs thrown at them because of their goofy acts or when actors had eggs thrown at them performing in plays a couple of centuries ago.>>

Keyman · Post by **Keyman** » Fri Feb 01, 2013 4:43 pm

Wow. You grammarian dudes. Chill. You're being, such as, real picky.

neufer · Post by **neufer** » Fri Feb 01, 2013 5:11 pm

Keyman wrote:
Wow. You grammarian dudes. Chill. You're being, such as, real picky.

Like totally, Man! Duh!

(I know bystander is probably going to give me a ticket or something but...)

http://en.wikipedia.org/wiki/Valley_girl#Sociolect wrote:
Click to play embedded YouTube video.
<<Valley girl is a stereotype depicting a socio-economic and ethnic class of white women characterized by the colloquial California English dialect Valleyspeak and vapid materialism. The term originally referred to an ever increasing swell of semi-affluent and affluent middle-class and upper-middle class girls living in the early 1980s Los Angeles bedroom communities of San Fernando Valley. In time the traits and behaviors spread across the United States and abroad, metamorphosizing into a caricature of unapologetically spoiled "ditzes" and "airheads" more interested in shopping, personal appearance and social status than intellectual development or personal accomplishment. A sociolect associated with Valley Girls termed “Valspeak” spread across the United States during the 1980s and 1990s, heavily populating high-school teenage female slang throughout. Qualifiers such as “like”, “whatever”, “way”, "as if!", “totally”, and “duh” were interjected in the middle of phrases and sentences as emphasizers. Narrative sentences were often spoken as if questions using a high rising terminal. Heavily accented words were spoken with high variation in pitch combined with very open or nasal vowel sounds.>>

LocalColor · Post by **LocalColor** » Fri Feb 01, 2013 5:30 pm

Very interesting photo. Curious about the exposure and camera settings.

MargaritaMc · Post by **MargaritaMc** » Fri Feb 01, 2013 5:50 pm

I've looked and looked at this Apod, trying to work out why, if it is going up to an orbit of 20,000+miles, the trail doesn't continue straight up. Why does the J curve happen?

There is probably an absolutely obvious answer - but I promise that I won't respond with Duh!

Margarita

Chris Peterson · Post by **Chris Peterson** » Fri Feb 01, 2013 6:12 pm

MargaritaMc wrote:I've looked and looked at this Apod, trying to work out why, if it is going up to an orbit of 20,000+miles, the trail doesn't continue straight up. Why does the J curve happen?

It's not "J" shaped- that's a projection illusion created by the position of the photographer. Rockets designed to place satellites in orbit can't just go straight up, however. After liftoff, they start adding a sideways component. This is typically to the east (to take advantage of Earth's rotation), with other components to minimize the fuel required in additional burns needed to place the satellite in its final orbit (in this case, a geostationary orbit). You can picture this as the rocket "merging" with the final orbit, as opposed to climbing to the correct height and then executing a 90° turn.

BPCooper · Post by **BPCooper** » Fri Feb 01, 2013 7:01 pm

Thanks for the comments.

When a rocket launches, it arcs downrange and heads parallel to Earth's surface for the most part (far more so than it gains altitude). From the position near the launch site, the rocket appears to head up and then out towards the horizon, thus in photos looking like it is going "down."

This exposure is about 4 minutes 45 seconds but begins about 2 minutes before liftoff. The crazy yellow color cast on the dishes is from some old, nearby lights that were yellow-green in color.

neufer · Post by **neufer** » Fri Feb 01, 2013 7:19 pm

: [b][color=#0000FF][size=150]Space Shuttle Nominal Launch Trajectory[/size][/color][/b]

MargaritaMc wrote:
I've looked and looked at this Apod, trying to work out why, if it is going up to an orbit of 20,000+miles, the trail doesn't continue straight up. Why does the J curve happen?

Once a rocket is safely above the Earth's turbulent boundary layer (i.e., the first mile) it starts working on gaining sufficient horizonal momentum so as to go into a low Earth orbit (LEO) by 100 miles altitude.

It only takes ~1/40 (=100 miles/4000 miles) escape velocity energy to lift a rocket up to an altitude of 100 miles; however, it require ~1/2 escape velocity energy to actually go into orbit at that altitude.

From low Earth orbit (LEO) a rocket can go into any higher orbit
or it can go to the moon and beyond.

: [b][color=#0000FF][size=150]Space Shuttle Nominal Launch Trajectory[/size][/color][/b] [url=http://www.aerospaceweb.org/question/spacecraft/q0278.shtml]and Return To Launch Site abort profile[/url]

Click to play embedded YouTube video.

MargaritaMc · Post by **MargaritaMc** » Sat Feb 02, 2013 9:49 am

Thank you for all those informative responses - most appreciated by this newbie.

The Wikipedia article on Escape Velocity says,

On the surface of the Earth, the escape velocity is about 11.2 kilometers per second (~6.96 mi/s), which is approximately 34 times the speed of sound (Mach 34) and several times the muzzle velocity of a rifle bullet (up to 1.7 km/s). However, at 9,000 km altitude in "space", it is slightly less than 7.1 km/s.
http://en.m.wikipedia.org/wiki/Escape_v ... #section_1

Which I found pretty astounding.

By the way - does the '~' ( which I've coloured purple in the quote above) stand for 'approximately' or 'that is' - or something else entirely?

The difficulty with symbols is that they are difficult to look up in dictionaries or to Google, if you don't know how they are said!

And what about the double wavy lines in this, which refers to something to do with Lagrangean points? (I'm looking up orbits of various space telescopes, so it is slightly connected to this thread)

Margarita

MargaritaMc · Post by **MargaritaMc** » Sat Feb 02, 2013 1:39 pm

http://en.m.wikipedia.org/wiki/List_of_ ... al_symbols

I am replying to my own question!

Wikipedia has a full list of the symbols used in maths at the link above.
Margarita

Starship Asterisk*

APOD: Atlas V Launches TDRS-K (2013 Feb 01)

APOD: Atlas V Launches TDRS-K (2013 Feb 01)

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Exempli gratia

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