Is this NASA page correct?

I was wondering about Jason-3 being launched from Vandeberg and was
looking up orbital inclination - if I recall correctly that satellite
is to be at 60-odd degrees. If I've understood things correctly, that
means the launch will not be all that out over the Pacific, but I may
not have understood things correctly...

Anyway, along the way I came across
http://earthobservatory.nasa.gov/Fea...OrbitsCatalog/ which has a
paragraph which reads:


Achieving and Maintaining Orbit
Launch

The amount of energy required to launch a satellite into orbit
depends on the location of the launch site and how high and how
inclined the orbit is. Satellites in high Earth orbit require the
most energy to reach their destination. Satellites in a highly
inclined orbit, such as a polar orbit, take more energy than a
satellite that circles the Earth over the equator. A satellite
with a low inclination can use the Earth’s rotation to help boost
it into orbit. The International Space Station orbits at an
inclination of 51.6397 degrees to make it easier for the Space
Shuttle and Russian rockets to reach it. A polar-orbiting
satellite, on the other hand, gets no help from Earth’s momentum,
and so requires more energy to reach the same altitude.

That last sentence in particular caught my attention. I thought that
reaching a given altitude was always the same quantity of energy
necessary from the rocket, and that it was achieving orbital velocity
that differed based on the orbit and launch site?

rick jones
--
I don't interest myself in "why." I think more often in terms of
"when," sometimes "where;" always "how much." - Joubert
these opinions are mine, all mine; HPE might not want them anyway...
feel free to post, OR email to rick.jones2 in hpe.com but NOT BOTH...

On 1/15/2016 6:11 PM, Rick Jones wrote :
I was wondering about Jason-3 being launched from Vandeberg and was
looking up orbital inclination - if I recall correctly that satellite
is to be at 60-odd degrees. If I've understood things correctly, that
means the launch will not be all that out over the Pacific, but I may
not have understood things correctly...

Anyway, along the way I came across
http://earthobservatory.nasa.gov/Fea...OrbitsCatalog/ which has a
paragraph which reads:


Achieving and Maintaining Orbit
Launch

The amount of energy required to launch a satellite into orbit
depends on the location of the launch site and how high and how
inclined the orbit is. Satellites in high Earth orbit require the
most energy to reach their destination. Satellites in a highly
inclined orbit, such as a polar orbit, take more energy than a
satellite that circles the Earth over the equator. A satellite
with a low inclination can use the Earth’s rotation to help boost
it into orbit. The International Space Station orbits at an
inclination of 51.6397 degrees to make it easier for the Space
Shuttle and Russian rockets to reach it. A polar-orbiting
satellite, on the other hand, gets no help from Earth’s momentum,
and so requires more energy to reach the same altitude.

That last sentence in particular caught my attention. I thought that
reaching a given altitude was always the same quantity of energy
necessary from the rocket, and that it was achieving orbital velocity
that differed based on the orbit and launch site?

The altitude of the orbit depends on orbital velocity.


Alain Fournier

In article , says...

The amount of energy required to launch a satellite into orbit
depends on the location of the launch site and how high and how
inclined the orbit is. Satellites in high Earth orbit require the
most energy to reach their destination. Satellites in a highly
inclined orbit, such as a polar orbit, take more energy than a
satellite that circles the Earth over the equator. A satellite
with a low inclination can use the Earth?s rotation to help boost
it into orbit. The International Space Station orbits at an
inclination of 51.6397 degrees to make it easier for the Space
Shuttle and Russian rockets to reach it. A polar-orbiting
satellite, on the other hand, gets no help from Earth?s momentum,
and so requires more energy to reach the same altitude.

That last sentence in particular caught my attention. I thought that
reaching a given altitude was always the same quantity of energy
necessary from the rocket, and that it was achieving orbital velocity
that differed based on the orbit and launch site?

Generally launches from the US try very hard to *not* fly over land
(i.e. populated areas) just in case the launch fails and rocket parts
including toxic chemicals come raining down.

Because of the earth's rotation, launching from the east coast into an
orbit that is in (generally) an eastward direction takes less energy
than if one were to launch from the west coast in a (generally) westward
direction.

Here is an awesome (old) graphic showing this for space shuttle
launches. Even though the shuttle never launched from Vandenberg Air
Force Base, this information is still applicable to other launches from
that site.

Space Shuttle Launch Sites - Azimuths and Inclinations
http://i.stack.imgur.com/JwFty.jpg

Jeff
--
"the perennial claim that hypersonic airbreathing propulsion would
magically make space launch cheaper is nonsense -- LOX is much cheaper
than advanced airbreathing engines, and so are the tanks to put it in
and the extra thrust to carry it." - Henry Spencer

In article , says...

On 1/15/2016 6:11 PM, Rick Jones wrote :

That last sentence in particular caught my attention. I thought that
reaching a given altitude was always the same quantity of energy
necessary from the rocket, and that it was achieving orbital velocity
that differed based on the orbit and launch site?

The altitude of the orbit depends on orbital velocity.

Yes, but you did not explain how the earth's rotation can either help or
hinder attaining that orbital velocity. That is the key here.

Launch a rocket from a spinning planet
http://spaceplace.nasa.gov/launch-windows/en/

Jeff
--
"the perennial claim that hypersonic airbreathing propulsion would
magically make space launch cheaper is nonsense -- LOX is much cheaper
than advanced airbreathing engines, and so are the tanks to put it in
and the extra thrust to carry it." - Henry Spencer

On Sat, 16 Jan 2016 11:21:38 -0500, Jeff Findley
wrote:


Here is an awesome (old) graphic showing this for space shuttle
launches. Even though the shuttle never launched from Vandenberg Air
Force Base, this information is still applicable to other launches from
that site.

Space Shuttle Launch Sites - Azimuths and Inclinations
http://i.stack.imgur.com/JwFty.jpg

Note that the "SRB impact" zone for Vandenberg is way off. Like 500
miles off.

Brian

"Brian T." wrote in message
...

On Sat, 16 Jan 2016 11:21:38 -0500, Jeff Findley
wrote:


Here is an awesome (old) graphic showing this for space shuttle
launches. Even though the shuttle never launched from Vandenberg Air
Force Base, this information is still applicable to other launches from
that site.

Space Shuttle Launch Sites - Azimuths and Inclinations
http://i.stack.imgur.com/JwFty.jpg

Note that the "SRB impact" zone for Vandenberg is way off. Like 500
miles off.

Brian

Weren't the fiberwound SRBs supposed to burn longer, meaning a further
downrange impact point?

--
Greg D. Moore http://greenmountainsoftware.wordpress.com/
CEO QuiCR: Quick, Crowdsourced Responses. http://www.quicr.net

"Fred J. McCall" wrote in message
...

"Greg \(Strider\) Moore" wrote:


Weren't the fiberwound SRBs supposed to burn longer, meaning a further
downrange impact point?


I don't know if they burned longer, but the cases were much lighter
and so they would land further downrange due to reduced dry mass
giving an increase in delta-V.



Yeah, either way, I'm thinking they ended up further downrange.
Not if it's 500 miles though (and not sure how you can tell from that
graphic that it's 500 miles :-)


--
Greg D. Moore http://greenmountainsoftware.wordpress.com/
CEO QuiCR: Quick, Crowdsourced Responses. http://www.quicr.net

In article ,
says...

"Fred J. McCall" wrote in message
...

"Greg \(Strider\) Moore" wrote:


Weren't the fiberwound SRBs supposed to burn longer, meaning a further
downrange impact point?


I don't know if they burned longer, but the cases were much lighter
and so they would land further downrange due to reduced dry mass
giving an increase in delta-V.



Yeah, either way, I'm thinking they ended up further downrange.
Not if it's 500 miles though (and not sure how you can tell from that
graphic that it's 500 miles :-)

I'm not sure where this graphic originally came from. I was only using
it to show why launch inclinations are what they are for Vandenberg
versus KSC/Cape Canaveral. In other words, the "don't overfly land"
constraint.

Jeff
--
"the perennial claim that hypersonic airbreathing propulsion would
magically make space launch cheaper is nonsense -- LOX is much cheaper
than advanced airbreathing engines, and so are the tanks to put it in
and the extra thrust to carry it." - Henry Spencer

On Sun, 24 Jan 2016 10:15:58 -0500, Jeff Findley
wrote:


Yeah, either way, I'm thinking they ended up further downrange.
Not if it's 500 miles though (and not sure how you can tell from that
graphic that it's 500 miles :-)

I'm not sure where this graphic originally came from. I was only using
it to show why launch inclinations are what they are for Vandenberg
versus KSC/Cape Canaveral. In other words, the "don't overfly land"
constraint.

It is a good illustration for the launch azimuth restrictions, but
someone seriously botched the SRB impact distance.

I missed it the first time I looked at it, but the "SRB Impact" arc
for Kennedy is equally wrong.

The SRB splashdown area was about 150 miles from KSC, which on a
high-inclination (northeast) flight was off Jacksonville, Florida.
(Not coincidentally, more or less the same place SpaceX parks its
barge on CRS flights.) This illustraion shows it off, roughly,
Norfolk, Virgnia.

Brian

On Thu, 04 Feb 2016 00:52:09 -0700, Fred J. McCall
wrote:


The SRB splashdown area was about 150 miles from KSC, which on a
high-inclination (northeast) flight was off Jacksonville, Florida.
(Not coincidentally, more or less the same place SpaceX parks its
barge on CRS flights.) This illustraion shows it off, roughly,
Norfolk, Virgnia.


I didn't look at it, but SRB splashdown range is nominally around 120
nautical miles, so the 150 mile SRB impact range seems about right.

Agreed, but the illustration shows it at 600 miles or so.

Brian