Re: [PLUG] OT: 7 minutes of terror, Curiosity landing on Mars 01:30 EDT Monday

[Walt Mankowski <waltman@pobox.com>]

You're of course right that the speed of light is a constant, but
you're off by more than an order of magnitude in your guess about the
lag.

The distance between Earth and Mars varies between about 35 million
and 400 million km depending on where each planet happens to be in its
orbit [1].  Since light travels about 300,000 km/sec, that works out
to between roughly 2 minutes and 22 minutes, respectively.  Right now
Mars is about in the middle between those two extremes, and signals
from Curiosity are taking about 14 minutes to reach Earth.

Walt

1. http://www.space.com/16875-how-far-away-is-mars.html

On Mon, Aug 06, 2012 at 07:18:07PM -0700, Bob Schwier wrote:
> 
> 
> --- On Sat, 8/4/12, Nicholas Gasparovich <nick@gasponet.com> wrote:
> 
> Thirty second lag at best.  The speed of light is not going to change for you.  As old as Ron, graduated from Wheaton High (Wheaton MD) the same year.  Served on Independence.  Uncle sent me to defend the Med and not Nam.  Anyway, I'm old and gravity sucks so ending my life on a one way trip to a dream is not a bad idea.
> bs  
> 
> As long as Mars has FIOS, then I'm all aboard, lol
> -Nick
> On Aug 4, 2012 7:17 PM, "Ron Kaye Jr" <rekaye1005@verizon.net> wrote:
> 
>  the americans have gotten very good at this process.
> 
> but the russians have not fared so well.
> 
> 
> 
> are you prepared to volunteer for the 1st manned flight.
> 
> apparently you get to mars, with no plans for coming back.
> 
> 
> 
> i share your enthusiam for space exploration.
> 
> i had just graduated from springfield high in 1969.
> 
> my friends and i were touring the US in a trailer.
> 
> i was visiting my cousin, on a huge naval vessel in san diego,
> 
> first week of august.
> 
> 
> 
> neil armstrong became the symbol of the greatest accomplishment of mankind.
> 
> it was an exciting time.
> 
> we need to reengage as a nation in this inspirational activity
> 
> 
> 
> Ron Kaye Jr
> 
> 914-7294734
> 
> 
> 
> On 08/04/12, Lee H. Marzke wrote:
> 
> 
> 
> 
> 
> FYI,
> 
> 
> 
> NASA's Curiosity is scheduled to land on Mars at 01:30 EDT early Monday morning
> 
> (Aug 6, 2012) after traveling over 500,000 miles. It's mission is to understand the
> 
> 'habitability of Mars". In other words are their conditions that could have ever supported
> 
> life on Mars ( not specifically looking for life itself )
> 
> 
> 
> View it at NASA TV: Live coverage begin 6PM EDT Sunday
> 
> http://www.ustream.tv/nasa
> 
> 
> 
> 
> 
> Re-entry (called the 7 minutes of terror ) begins with Curiosity hitting the atmosphere
> 
> at 13,200 Mph and using a combination of head shields, and supersonic drogue chute
> 
> to slow to 200mph, and retro rockets for the rest of the way. The rover is actually
> 
> lowered on a 'sky-crane' to hang 7.5 meters below the rocket platform, and when
> 
> the rover touches, the cables are severed and the rocket platform flies away from the rover to
> 
> crash a short distance away. This keeps the level of dust and debris at the landing site
> 
> to acceptable levels.
> 
> 
> 
> Landing is scheduled into Gale crater which has central 3-mile high mountain peak.
> 
> 
> 
> Three satellites that have been in orbit around Mars since NASA:Odyssey:2001
> 
> ESA:MarsExpress:2003,
> 
>  NASA:MRO:2006, etc. will relay the spacecraft signals back to earth.
> 
> The communication will need to switch between these relay stations
> 
> during re-entry, and it's possible that communication will be lost for
> 
> for part or all of the re-entry. Communication
> 
> delay is 14 minutes for the signal to reach earth from Mars, so when we get the signal
> 
> that re-entry is beginning, the spacecraft's fate will have already happened 7 minutes
> 
> prior.
> 
> 
> 
> The landing results may be known immediately at landing, or delayed up to three
> 
> days if communication is lost.
> 
> 
> 
> Lee
> 
> 
> 
> --
> 
> 
> 
> "Between subtle shading and the absence of light lies the nuance of iqlusion..." - Kryptos
> 
> 
> 
> Lee Marzke, lee@marzke.net http://marzke.net/lee/
> 
> IT Consultant, VMware, VCenter, SAN storage, infrastructure, SW CM
> 
> 
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> 
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