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-   -   What "weed need" is a space mission! (https://www.mersenneforum.org/showthread.php?t=17609)

only_human 2015-05-06 06:35

[URL="http://qz.com/398306/watch-the-moon-wobble-its-way-through-all-of-2015-in-this-nasa-video/"]Watch the moon wobble its way through all of 2015 in this NASA video[/URL]
[QUOTE]Thanks to NASA’s Lunar Reconnaissance Orbiter, a satellite that has orbited the moon since 2009, we can see what that wobble will look like for all of 2015 in the span of five minutes. The video also shows the moon’s phases—[strike]in other words, changes in its visibility due to shadows cast on the moon by the Earth.[/strike]

The video shows the moon at hourly intervals, compressing a month into 24 seconds. All in all, about 59% of the moon is visible from Earth over the course of a year, rather than just the half that would be visible if libration did not occur.
[/QUOTE]
[YOUTUBE]30BUS6AslRo[/YOUTUBE]

Nick 2015-06-14 11:31

[QUOTE=Nick;397562]From today, the European Space Agency is listening to see whether the comet lander Philae starts transmitting again.

ESA Rosetta project blog entry: [URL]http://blogs.esa.int/rosetta/2015/03/10/waiting-for-a-signal-from-philae/[/URL][/QUOTE]
The European Space Agency (ESA) says its comet lander, Philae, has just woken up and contacted Earth.

Press article: [URL]http://www.bbc.com/news/science-environment-33126885[/URL]

Uncwilly 2015-06-14 13:33

[QUOTE=Nick;404050]The European Space Agency (ESA) says its comet lander, Philae, has just woken up and contacted Earth.[/QUOTE]:skiing:

xilman 2015-06-14 13:46

[QUOTE=only_human;401823]
[quote]rather than just the half that would be visible if libration did not occur.[/quote]
[/QUOTE]Just spotted this claim. Surely it must be false? The moon is relatively close to the earth and the parallax shift over an earth's diameter (i.e. the difference between moonrise and moonset) is appreciable. Consequently more than 50% must be visble from this effect alone.

retina 2015-06-14 14:01

What are the chances of getting [url=https://en.wikipedia.org/wiki/New_Horizons]New Horizons[/url] to take another [url=https://en.wikipedia.org/wiki/Family_Portrait_%28Voyager%29]family portrait[/url]?

chalsall 2015-06-24 13:38

[URL="http://www.extremetech.com/extreme/208803-spacex-will-try-landing-a-falcon-9-rocket-on-a-drone-ship-again-this-sunday"]SpaceX will try landing a Falcon 9 rocket on a drone ship again this Sunday[/URL].

only_human 2015-06-28 03:59

This article about tomorrow's SpaceX landing attempt explains how the last two attempts failed:
[QUOTE]During the first try in January, the rocket ran out of hydraulic fluid needed to maneuver small, foldable steering fins. The rocket, which is as tall as a 14-story building, crashed into the landing platform and exploded.

SpaceX tried again to land a Falcon in April and nearly nailed it. The supersonic descent through the atmosphere was successful, but about 10 seconds before touchdown a valve that was controlling the rocket’s final braking burn had a glitch that caused it to throttle down a few seconds later than planned. The 67,000-pound stage, now traveling at nearly 200 mph, lost control for a moment. It recovered, but not in time to prevent the rocket from tipping over, causing another fireball.[/QUOTE]

chalsall 2015-06-28 14:25

Shit!
 
Boom!

only_human 2015-06-28 23:21

The time of flight is possibly slightly after [URL="https://en.wikipedia.org/wiki/Max_Q"]Max Q[/URL]:
[QUOTE]During a normal Space Shuttle launch, for example, max Q occurred at an altitude of approximately 11 km (35,000 ft).[1] The three Space Shuttle Main Engines were throttled back to about 60-70% of their rated thrust (depending on payload) as the dynamic pressure approached max Q;[2] combined with the propellant perforation design of the solid rocket boosters, which reduced the thrust at max Q by one third after 50 seconds of burn, the total stresses on the vehicle were kept to a safe level.[/QUOTE]

A GIF of the SpaceX rocket launch that I looked at has as an inset data info window stating that the rocket was at Max Q.
[url]http://www.popularmechanics.com/space/rockets/a16226/space-third-barge-landing-fail/[/url]

[url]http://spacexstats.com/faq.php[/url]
[QUOTE]How fast is Falcon 9 going when it reaches Max-Q?
This is dependent on the payload being carried, but only slightly. It is generally travelling between Mach 1 & Mach 2 at roughly ~78 seconds into its flight.[/QUOTE]
The next scheduled SpaceX resupply mission is in September. I didn't look at other providers schedules.
[url]http://spacexstats.com/upcoming.php[/url]
[QUOTE]2 Sep 2015 SpaceX CRS-8 NASA Falcon 9 v1.1 SLC-40, Florida
The eighth cargo resupply mission of Dragon to the ISS. Notably, Bigelow Aerospace will provide the BEAM inflatable module as unpressurized cargo to be attached to the station.[/QUOTE]

The video footage places the rocket even closer to the Max Q event time than the above factoid indicated.
[url]https://youtube.com/watch?v=YlrqgCwEzQ4[/url]
[YouTube]YlrqgCwEzQ4[/YouTube]

chalsall 2015-06-28 23:32

[QUOTE=only_human;404959]A GIF of the SpaceX rocket launch that I looked at has as an inset data info window stating that the rocket was at Max Q. [url]http://www.popularmechanics.com/space/rockets/a16226/space-third-barge-landing-fail/[/url][/QUOTE]

The problem appears to have been with the LOX tank in the second stage (according to a "tweat" by Musk). If you watch the video carefully you can see that the initial explosion occurs near the front of the "stack". The first stage continues to thrust away for a couple of additional seconds before it also explodes.

A very sad day.

Dubslow 2015-07-01 06:24

Wasn't the rocket (and stage 1) deliberately exploded (either by a computer or the range officer)?


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