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SpinLaunch



 
 
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  #1  
Old February 25th 18, 02:21 AM posted to sci.space.policy
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Posts: 687
Default SpinLaunch

"SpinLaunch is raising $30 million to use large centrifuges to power catapult to
launch payloads into space. They use large centrifuges to store energy and will
then rapidly transfer that momentum into a catapult to send a payload to space at
up to 4,800 kilometers per hour (3,000 mph). If successful, the acceleration
architecture is projected to be both lower cost and use much less power, with the
price of a single space launch reduced to under US$500,000."

See:

https://www.nextbigfuture.com/2018/0...er-launch.html


Feasible?
  #3  
Old February 25th 18, 03:51 PM posted to sci.space.policy
Jeff Findley[_6_]
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Posts: 2,307
Default SpinLaunch

In article ,
says...

"SpinLaunch is raising $30 million to use large centrifuges to power catapult to
launch payloads into space. They use large centrifuges to store energy and will
then rapidly transfer that momentum into a catapult to send a payload to space at
up to 4,800 kilometers per hour (3,000 mph). If successful, the acceleration
architecture is projected to be both lower cost and use much less power, with the
price of a single space launch reduced to under US$500,000."

See:

https://www.nextbigfuture.com/2018/0...er-launch.html


Feasible?


Maybe. But quite challenging. At the high acceleration required by
this approach, the projectile must be fairly hardened. Also, at the
high low altitude speeds this thing will be traveling, atmospheric
heating is an issue. And finally, even if the catapult can get it to
orbital altitude and velocity, it will never get into orbit without a
rocket engine to circularize the orbit.

From the projectile's point of view, this isn't much different than the
past "gun launch" proposals. Pretty much all of the same issues apply.

Jeff
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  #4  
Old February 25th 18, 05:32 PM posted to sci.space.policy
Alain Fournier[_3_]
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Posts: 548
Default SpinLaunch

On Feb/25/2018 at 9:51 AM, Jeff Findley wrote :
In article ,
says...

"SpinLaunch is raising $30 million to use large centrifuges to power catapult to
launch payloads into space. They use large centrifuges to store energy and will
then rapidly transfer that momentum into a catapult to send a payload to space at
up to 4,800 kilometers per hour (3,000 mph). If successful, the acceleration
architecture is projected to be both lower cost and use much less power, with the
price of a single space launch reduced to under US$500,000."

See:

https://www.nextbigfuture.com/2018/0...er-launch.html


Feasible?


Maybe. But quite challenging. At the high acceleration required by
this approach, the projectile must be fairly hardened. Also, at the
high low altitude speeds this thing will be traveling, atmospheric
heating is an issue. And finally, even if the catapult can get it to
orbital altitude and velocity, it will never get into orbit without a
rocket engine to circularize the orbit.

From the projectile's point of view, this isn't much different than the
past "gun launch" proposals. Pretty much all of the same issues apply.

Jeff



The issues of gun launch apply to SpinLaunch. But SpinLaunch has some
issues of its own. Having a payload at very high speed spinning in
the launch apparatus without tearing apart the whole thing would be
quite a challenge.

I might be wrong but I suspect those proposing SpinLaunch are aware of
the problems. Their business plan is probably more about collecting
investors money than about putting anything in orbit.


Alain Fournier
  #5  
Old February 28th 18, 01:09 AM posted to sci.space.policy
Greg \(Strider\) Moore
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Posts: 752
Default SpinLaunch

wrote in message
...

"SpinLaunch is raising $30 million to use large centrifuges to power
catapult to
launch payloads into space. They use large centrifuges to store energy and
will
then rapidly transfer that momentum into a catapult to send a payload to
space at
up to 4,800 kilometers per hour (3,000 mph). If successful, the
acceleration
architecture is projected to be both lower cost and use much less power,
with the
price of a single space launch reduced to under US$500,000."

See:

https://www.nextbigfuture.com/2018/0...er-launch.html


Feasible?


Is strikes me that someone has read The Brick Moon by Edward Everett Hale.


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  #6  
Old February 28th 18, 02:09 AM posted to sci.space.policy
Sylvia Else
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Posts: 1,063
Default SpinLaunch

On 26/02/2018 3:32 AM, Alain Fournier wrote:
On Feb/25/2018 at 9:51 AM, Jeff Findley wrote :
In article ,
says...

"SpinLaunch is raising $30 million to use large centrifuges to power
catapult to
launch payloads into space. They use large centrifuges to store
energy and will
then rapidly transfer that momentum into a catapult to send a payload
to space at
up to 4,800 kilometers per hour (3,000 mph). If successful, the
acceleration
architecture is projected to be both lower cost and use much less
power, with the
price of a single space launch reduced to under US$500,000."

See:

https://www.nextbigfuture.com/2018/0...er-launch.html



Feasible?


Maybe. But quite challenging. At the high acceleration required by
this approach, the projectile must be fairly hardened. Also, at the
high low altitude speeds this thing will be traveling, atmospheric
heating is an issue. And finally, even if the catapult can get it to
orbital altitude and velocity, it will never get into orbit without a
rocket engine to circularize the orbit.

From the projectile's point of view, this isn't much different than the
past "gun launch" proposals. Pretty much all of the same issues apply.

Jeff



The issues of gun launch apply to SpinLaunch. But SpinLaunch has some
issues of its own. Having a payload at very high speed spinning in
the launch apparatus without tearing apart the whole thing would be
quite a challenge.

I might be wrong but I suspect those proposing SpinLaunch are aware of
the problems. Their business plan is probably more about collecting
investors money than about putting anything in orbit.

The issues are mentioned in the three page paper linked from the
article. They comment, amongst other things, that missiles have
electronics that has to stand 20,000g. No doubt that's true, but having
to design complete spacecraft to such a specification would be
demanding, and would surely hugely increase their mass. I don't see this
as being practical.

Sylvia.

  #7  
Old March 1st 18, 11:05 PM posted to sci.space.policy
David Spain
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Posts: 2,901
Default SpinLaunch

These g loads are tremendous. I'd like to see the rocket motor that
could survive them (10,000 g) to provide the needed kick at apogee.

I'd also like to see some of the engineering needed to do that in a ring
that isn't evacuated, or under near vacum.

To date the one I know of that could operate at high G load was the
solid fuel Sprint missile, at it *only* accelerated at 100g! Down two
whole orders of magnitude.

But then there was the HIBEX missile at 400G also solid fueled
star-grained FDN-80. Still both of these are down two orders of
magnitude from 10,000g.

https://en.wikipedia.org/wiki/Sprint_%28missile%29

Excerpt from para. 2:

Sprint accelerated at 100 g, reaching a speed of Mach 10 in 5 seconds. Such a high velocity at relatively low altitudes created skin temperatures up to 6200 °F (3400 °C), requiring an ablative shield to dissipate the heat.[1][2] The high temperature caused a plasma to form around the missile, requiring extremely powerful radio signals to reach it for guidance.


Plasma during atmopheric ascent, also while accelerating in a non-evac
ring or rail. Fun also to consider.

I think mag-lev rail guns would be more useful for getting things off
the airless moon rather than the Earth. Just a hunch. I think rockets
are safe for now.

If you are looking for cheap lift, why not a water fueled, laser & steam
driven rocket?

For all that, the upcoming methalox approaches are going to be a
challenge to beat....

Dave
  #8  
Old March 1st 18, 11:17 PM posted to sci.space.policy
David Spain
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Posts: 2,901
Default SpinLaunch

On 3/1/2018 5:05 PM, David Spain wrote:
These g loads are tremendous. I'd like to see the rocket motor that
could survive them (10,000 g) to provide the needed kick at apogee.


Even if you are using a evacuated launch tube, you'll be pulling
tremendous negative g's when slamming into the atmosphere at launch
point. Maybe that's the bulk of the g load? Oops I see I misread the g
load originally by a factor of 4 to 6x. So make that 40-60,000g's.

Yah.

Dave
 




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