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Elon Musk's SpaceX to build 'Grasshopper' hover-rocket



 
 
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  #51  
Old October 12th 11, 11:33 PM posted to sci.space.policy
Dr J R Stockton[_132_]
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Default Elon Musk's SpaceX to build 'Grasshopper' hover-rocket

In sci.space.policy message
, Mon, 10 Oct 2011 19:00:54, Brian Thorn
posted:

On Mon, 10 Oct 2011 16:12:45 +0100, Dr J R Stockton
wrote:


The US Government seems more likely to
go broke than the telecoms industry.


No, it isn't. Ask Iridium about that, which went broke and was bailed
out by the government (DoD). Teledesic had a contract for lots of
Delta III launches, too. They went kaput.



Iridium was only a small part of the telecoms industry, most of which is
not even in the United States. But the USA has just the one Federal
Government. The USG is quite capable of following where the Greeks are
leading.



But I am not considering ISS or polar missions.


The problem is that the market simply isn't big enough to justify a
GEO-bound-only launch site. With the big satellites lasting well over
a decade and costing hundreds of millions of dollars each, replacement
launches are few and far between. Having a 50% cheaper launcher is not
going to create double or triple the demand for GEO comsats. And would
SpaceX be able to reach 50% cheaper while paying for all new launch
infrastructure/processing/range at South Padre Island, or an aircraft
carrier in the Atlantic? Mr. Musk is good, but he's not *that* good.


Judging by his ability to build rockets, he should be able to build and
operate launch sites for 10% of what a NASA site would cost. In effect,
he's doing that already at CCAFS.


BTW, I checked the North Shore of the Gulf of Mexico in Google Maps. A
lot of wildlife refuges, but not continuous. A lot of residential, but
not continuous. In between, unused shore-land.

Given the size of Falcon 1 (one), and noting that there is a railway
line beside his works, ISTM a pity that (AFAIK) he didn't get it to
launch from a train.

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  #52  
Old October 13th 11, 12:10 AM posted to sci.space.policy
Rick Jones
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Default Elon Musk's SpaceX to build 'Grasshopper' hover-rocket

Brian Thorn wrote:
No, it isn't. Ask Iridium about that, which went broke and was
bailed out by the government (DoD).


I thought that Iridium went through a "proper" bankruptcy and that the
folks who picked-up the assets on the cheap were then able to sustain
operations based in no small part on contracts with the
U.S. Government?

http://en.wikipedia.org/wiki/Iridium...ations#History

rick jones
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  #53  
Old October 13th 11, 12:52 AM posted to sci.space.policy
Brian Thorn[_2_]
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Default Elon Musk's SpaceX to build 'Grasshopper' hover-rocket

On Wed, 12 Oct 2011 23:33:07 +0100, Dr J R Stockton
wrote:


Iridium was only a small part of the telecoms industry, most of which is
not even in the United States. But the USA has just the one Federal
Government. The USG is quite capable of following where the Greeks are
leading.


Perhaps, but in that case we're talking an economic calamity that
dwarfs the Great Depression. I don't see the telecom industry
remaining particularly strong in such an event.

Judging by his ability to build rockets, he should be able to build and
operate launch sites for 10% of what a NASA site would cost. In effect,
he's doing that already at CCAFS.


No, he really isn't. He's paying to use the existing Cape
infrastructure, especially power, communications, tracking range and
payload processing facilities. And his pad is one of the two old Titan
IV pads, so he didn't start from scratch like he'll have to do
elsewhere. The same is true at Vandenberg, by the way, where he is
again using an old Titan pad. Starting over in Texas is going to be
considerably more expensive.

Brian
  #54  
Old October 13th 11, 08:40 PM posted to sci.space.policy
Mike DiCenso
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Default Elon Musk's SpaceX to build 'Grasshopper' hover-rocket

On Oct 12, 4:52*pm, Brian Thorn wrote:
No, he really isn't. He's paying to use the existing Cape
infrastructure, especially power, communications, tracking range and
payload processing facilities. And his pad is one of the two old Titan
IV pads, so he didn't start from scratch like he'll have to do
elsewhere. The same is true at Vandenberg, by the way, where he is
again using an old Titan pad. Starting over in Texas is going to be
considerably more expensive.


And that's not the only existing infrastructure Musk is making use of.
The test firings of the Falcon 9 stages were all conducted using what
remained of defunct Beal Aerospace's old test stands and facilities in
McGregor, Texas, which were originally intended for the never-built
BA-2 rocket. So if Musk had to build all that on his own, not simply
buy up and modify someone else's, he'd have had to spend much more,
and take more time than he already has.
-Mike
  #55  
Old October 17th 11, 05:28 PM posted to sci.space.policy,sci.space.history,sci.astro,sci.physics
Robert Clark
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Default Elon Musk's SpaceX to build 'Grasshopper' hover-rocket

On Oct 2, 7:17*pm, Robert Clark wrote:
*A couple of suggestions for the reusable version of the Falcon 9.
First, model it on the DC-X. In the SpaceX video of the proposed
reusable launcher the first and second stages have the same straight
sides of the expendable versions. But having sloping sides helps to
protect the sides of the vehicle during reentry as well as increasing
aerodynamic stability during reentry.
Note that as long as the cross-section remains circular for a conical
shaped stage you should still get the high tankage ratio that obtains
for cylindrical tanks:

...
The second model for the reusable Falcon 9 stages would be on the
ESA's proposed Intermediate eXperimental Vehicle (IXV):

Article:
Europe Aims to Launch Robotic Mini-Shuttle By 2020.
Rob Coppinger, SPACE.com ContributorDate: 13 June 2011 Time: 02:58 PM
EThttp://www.space.com/11948-robot-spa...hing-2020.html

This does not use the powered landing of the DC-X but rather uses a
glided landing via its lifting body shape. SpaceX does not like the
use of wings for landing because of the extra weight. But this design
would not have wings. It would have larger thermal protection weight
because the horizontal underside would have to be covered, whereas in
the DC-X mode only the base has to be covered. However, it would make
up for this in not requiring fuel for the powered landing.
In this case because the stages would have to maintain the aerodynamic
shape, they could not be stacked as for serial staging. Parallel
staging would have to be used. Once again this means the separate
stages could be used as SSTO's.


Another possible lifting-body shape for reusable Falcon 9 stages might
be of the Japanese HYFLEX hypersonic test vehicle:

Hypersonic Flight Experiment "HYFLEX".
http://www.jaxa.jp/projects/rockets/hyflex/index_e.html

HYFLEX.
http://www.rocket.jaxa.jp/fstrc/0c02.html

This was successfully tested all the way back in 1996 at a Mach 15
reentry speed.
It's roughly cylindrical shape would mean you would lose a relatively
small degree on the mass efficiency of cylindrically shaped tanks.
However, rather than redesigning the tanks you might want to just use
a composite aeroshell on the usual Falcon 9 stages. A conical
aeroshell for example was used on the DC-X.
This would make the reusable Falcon 9 more quickly and easily to be
implemented. The mass of the aeroshell though would contribute to the
mass lost from payload.
As with the above cases, if used with altitude compensating nozzles
on the Merlins or with existing high efficiency engines with just
their standard nozzles, these HYFLEX-shaped stages could also be
SSTO's.


Bob Clark
  #56  
Old November 19th 11, 12:47 PM posted to sci.space.policy
Dr J R Stockton[_14_]
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Posts: 16
Default Elon Musk's SpaceX to build 'Grasshopper' hover-rocket

On Oct 3, 6:26*pm, Dr J R Stockton
wrote:

...
launch from the Texas coast,
...


Some here disliked that idea. It appears (as I thought at the time)
that Elon Musk does not.

See for example
http://spaceflightnow.com/news/n1111/18spacexlaunchsite/.

Better, though, to buy an island in the Mouths of the Amazon; or to
rent space in CSG (E.M. no would probably appreciate the cooking
better there).

--
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