### Author Topic: Countdown to new smallsat launchers  (Read 144921 times)

#### c4fusion

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##### Re: Countdown to new smallsat launchers
« Reply #400 on: 02/26/2018 05:22 am »
Quote from: Bananas_on_Mars
I did a quick calculation, a centrifugal launcher that supplies 2000m/s and has a 20m radius would mean about 20.000g...
Is that a decimal point or have you mis placed a comma? 20g is less than an ICBM warhead at burn out.  20 000g is more like those GPS guided artillery shells the USN is currently using.  Obviously both are possible but the latter needs a much more specialized skill set to build.  Likewise quite small increases in diameter can lower the centripetal g load quite a lot.

20k, on the order of an artillery shell.  It definitely seems unreasonable.  Even if your launch cost was much cheaper, it would require anyone who wanted to fly on their spinning death machine to overbuild their satellites, making them either less capable or increasing their weight...

Also gravity scales linearly with diameter for the given tangential speed.  I am guessing you were thinking of small decreases in tangential speed will decrease the g load a lot.

#### Bananas_on_Mars

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##### Re: Countdown to new smallsat launchers
« Reply #401 on: 02/26/2018 05:47 am »
Sorry, german here, it's Twenty thousand g, we use a point for separating thousands, and a comma for decimal point.

Didn't think about the audience here.
« Last Edit: 02/26/2018 05:49 am by Bananas_on_Mars »

#### john smith 19

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##### Re: Countdown to new smallsat launchers
« Reply #402 on: 02/26/2018 02:30 pm »
Sorry, german here, it's Twenty thousand g, we use a point for separating thousands, and a comma for decimal point.

Didn't think about the audience here.
That explains it.  It's tricky keeping track of all the cultural variances when numbers are concerned.

People have odd ideas about the g loads payloads experience. The Shuttle was designed to keep them below 3g, partly because it was expected to carry "Payload Specialists" who might have failed the full astronaut selection process.  That was more the exception than the rule. Most ELV's are designed to operated up to 5 or even 8gs towards the end of flight, when near empty.

So 20g would be a more heavily built payload than satellite builders are used to, but not excessively so. 20 000g  is much more specialized. It's true objects like laptops dropping from knee height to a hard floor can sustain a 1000g deceleration and still work it's not sustained acceleration, over a period of minutes.
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#### john smith 19

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##### Re: Countdown to new smallsat launchers
« Reply #403 on: 02/26/2018 02:41 pm »
20k, on the order of an artillery shell.  It definitely seems unreasonable.  Even if your launch cost was much cheaper, it would require anyone who wanted to fly on their spinning death machine to overbuild their satellites, making them either less capable or increasing their weight...
True, but not necessarily a show stopper. I guess it depends on how those loads compare to those on the funfair ride known as the "Wall of Death."

It also depends if the concept has any features that can offset the high g issues? For example, could it do multiple launches in a single day?
Quote from: c4fusion
Also gravity scales linearly with diameter for the given tangential speed.  I am guessing you were thinking of small decreases in tangential speed will decrease the g load a lot.
Yes. Anything that can cut down the peak acceleration has to be a key design parameter. The joker is bigger radius --> bigger volume to evacuate.
That said I get the impression that the difficulty of vacuum pumping rises exponentially with pressure dropped. 1Pa is  1/100 000 of Sea Level pressure but by UHV standards is still "high pressure."
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#### Bananas_on_Mars

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##### Re: Countdown to new smallsat launchers
« Reply #404 on: 02/26/2018 03:16 pm »
Did some other calculations.
If you limit acceleration to 10 g, you will need 1000m of a straight rail for a sled or similar to reach 2000m/s.

What if they're just using a spinning wheel that can accumulate rotational impuls over longer time, and when it's spinning fast enough they couple it to a winch to accelerate some sled?

No vacuum necessary for something like that...

Just some random thoughts to make sense of the little information we've got...
« Last Edit: 02/26/2018 03:16 pm by Bananas_on_Mars »

#### HMXHMX

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##### Re: Countdown to new smallsat launchers
« Reply #405 on: 02/26/2018 03:49 pm »
People – the name is SPIN-launch.  Think it through.

#### Asteroza

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##### Re: Countdown to new smallsat launchers
« Reply #406 on: 02/28/2018 01:28 am »
People – the name is SPIN-launch.  Think it through.

They're not going to do an atmospheric tether spin catapult?!? Right?

I read elsewhere, speculatively they are spin launching a light gas gun to a high altitude, then fire the projectile from the gun, and gun lands in a reusable fashion. Somewhat rube goldberg and probably not scalable, even if feasible.

#### Lars-J

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##### Re: Countdown to new smallsat launchers
« Reply #407 on: 02/28/2018 07:08 am »
This (spinlaunch)  is one of those concept that sound more and more bonkers the more you read about it. It’s a complete non-starter in every practical sense. If they can get funding, it will be an interesting failure. Mark my words. Prove me wrong!

#### Robotbeat

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##### Re: Countdown to new smallsat launchers
« Reply #408 on: 02/28/2018 11:32 am »
People – the name is SPIN-launch.  Think it through.

They're not going to do an atmospheric tether spin catapult?!? Right?

I read elsewhere, speculatively they are spin launching a light gas gun to a high altitude, then fire the projectile from the gun, and gun lands in a reusable fashion. Somewhat rube goldberg and probably not scalable, even if feasible.
Who said the spinning would be done in atmosphere? It’s definitely not a gun, BTW.
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#### Robotbeat

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##### Re: Countdown to new smallsat launchers
« Reply #409 on: 02/28/2018 11:32 am »
This (spinlaunch)  is one of those concept that sound more and more bonkers the more you read about it. It’s a complete non-starter in every practical sense. If they can get funding, it will be an interesting failure. Mark my words. Prove me wrong!
Of course, but it’d be super cool to watch, so shush, you! 😂
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To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

#### Bananas_on_Mars

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##### Re: Countdown to new smallsat launchers
« Reply #410 on: 03/05/2018 04:33 pm »
an interview from Max Haot from a new rocket company called LAUNCHER that's based in New York.

A little bit different approach, but pretty appealing IMO.

and a bare homepage
« Last Edit: 03/05/2018 04:36 pm by Bananas_on_Mars »

#### Markstark

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##### Re: Countdown to new smallsat launchers
« Reply #411 on: 03/05/2018 04:54 pm »
an interview from Max Haot from a new rocket company called LAUNCHER that's based in New York.

A little bit different approach, but pretty appealing IMO.

and a bare homepage
Wow. 9 years to orbit. I appreciate the realism in their timeline. I hope the team is making income from other jobs.
« Last Edit: 03/05/2018 04:54 pm by Markstark »

#### Bananas_on_Mars

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##### Re: Countdown to new smallsat launchers
« Reply #412 on: 03/05/2018 05:01 pm »
Yes, i fear they might be a little late to the show, but if their plans work out only partially, they might still be able to make a living by selling their engines... though their plans are quite ambitious, developing a RP1 ORSC with about 10 mio \$...

#### Markstark

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##### Re: Countdown to new smallsat launchers
« Reply #413 on: 03/05/2018 05:08 pm »
Yes, i fear they might be a little late to the show, but if their plans work out only partially, they might still be able to make a living by selling their engines... though their plans are quite ambitious, developing a RP1 ORSC with about 10 mio \$...
Good point! There should be room for engine suppliers for companies that prefer COTS components were like ABL Space Systems

#### FutureSpaceTourist

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##### Re: Countdown to new smallsat launchers
« Reply #414 on: 03/15/2018 09:09 pm »
Quote
New Engine-1 🔥 from today - 6 second run followed by a 15 second run. Next week - 30+ goal.

#### FutureSpaceTourist

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##### Re: Countdown to new smallsat launchers
« Reply #415 on: 03/20/2018 06:15 am »
Quote
Smallsat launch providers face pricing pressure from Chinese vehicles
by Jeff Foust — March 19, 2018

WASHINGTON — Companies that are developing small launch vehicles or who provide rideshare launch services say they expect new Chinese launch vehicles to drive down launch prices, raising concerns among some of unfair competition.

http://spacenews.com/smallsat-launch-providers-face-pricing-pressure-from-chinese-vehicles/

#### Bananas_on_Mars

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##### Re: Countdown to new smallsat launchers
« Reply #416 on: 03/30/2018 12:49 pm »

#### Bananas_on_Mars

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##### Re: Countdown to new smallsat launchers
« Reply #417 on: 04/02/2018 05:53 pm »
And another short video from the "Launcher" control room for their test stand.

#### Katana

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##### Re: Countdown to new smallsat launchers
« Reply #418 on: 04/06/2018 04:04 pm »
Quote
Smallsat launch providers face pricing pressure from Chinese vehicles
by Jeff Foust — March 19, 2018

WASHINGTON — Companies that are developing small launch vehicles or who provide rideshare launch services say they expect new Chinese launch vehicles to drive down launch prices, raising concerns among some of unfair competition.

http://spacenews.com/smallsat-launch-providers-face-pricing-pressure-from-chinese-vehicles/
No ITAR?

#### Steven Pietrobon

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