Catapult to Orbit - SpinLaunch

[Spacescifi]

3 hours ago, sevenperforce said:

I suggest you spend some time reading about skyhooks.

 

Yeah... watched a video on space tethers... I presume same thing no?

 

I think an orbital version of spin launch would be superior... inasmuch you only need the arm and you already have vacuum outside so no disk.

Put enough of these in orbits and they become the 'roads' and 'intersections' of the solar system.

 

Transfer windows to them would still matter though,  so travel time would only be optimal when the spin arms were close enough... I am speaking of interplanetary spin launch satelites.

Edited December 7, 2021 by Spacescifi

[DDE]

The term "skyhook" seems weird and diluted. I've seen it applied to downright space elevators.

[grawl]

1 hour ago, Spacescifi said:

[...]

Put enough of these in orbits and they become the 'roads' and 'intersections' of the solar system.

 

Transfer windows to them would still matter though,  so travel time would only be optimal when the spin arms were close enough... I am speaking of interplanetary spin launch satelites.

That would be one... interesting... ride !

[Spacescifi]

41 minutes ago, grawl said:

That would be one... interesting... ride !

Sure... kind of requires a more mature manned space presence though since:

1. You need to launch all of that first. Would take years or decades to get all of it in place.

2 . Ideally manned craft would have enough water to submerse the crew while spinning. Thus they can spin at higher gees without injury or death.

3. Also centripetal spinning for gravity will be necessary on ALL manned spacecraft. Cannot likely survive the high spin of spin launch satelites otherwise I presume. Or at least without injury. I know the human body weakens at zero g, and I do not know what going from microgravity to 7 gees of spin would do to a person who has had microgravity for months. I suspect nothing good.

 

Edited December 7, 2021 by Spacescifi

[sevenperforce]

28 minutes ago, Spacescifi said:

Ideally manned craft would have enough water to submerse the crew while spinning. Thus they can spin at higher gees without injury or death.

Completely unnecessary. Skyhooks are very, very long; long enough that you don’t need high gees for a good launch. 

[JoeSchmuckatelli]

35 minutes ago, sevenperforce said:

Completely unnecessary. Skyhooks are very, very long; long enough that you don’t need high gees for a good launch. 

So you have this very long, ungodly strong line whipping down to the atmosphere and around to just as far above the atmosphere... How long does it take before you completely obliterate some satellite?  Or all that cross its path? 

You are basically going to need a completely clean orbital path the diameter of the circle, aren't you? 

[sevenperforce]

22 minutes ago, JoeSchmuckatelli said:

So you have this very long, ungodly strong line whipping down to the atmosphere and around to just as far above the atmosphere... How long does it take before you completely obliterate some satellite?  Or all that cross its path? 

You are basically going to need a completely clean orbital path the diameter of the circle, aren't you? 

Satellites are small and space is big. It’s not a significant issue. 

Most orbital skyhook designs utilize relatively low orbital paths with solar-electric propulsion modules at each end and at the center of mass. 
 

[JoeSchmuckatelli]

4 minutes ago, sevenperforce said:

Satellites are small and space is big. It’s not a significant issue. 

Most orbital skyhook designs utilize relatively low orbital paths with solar-electric propulsion modules at each end and at the center of mass. 
 

Most satellites are small and contained within the space defined by their own volume & solar panels.  Maybe the size of a football field for ISS.  And yeah, I get 'big sky, little bullet' but instead of dozens to hundreds of meters for average to large satellites - we are talking a line measured in kilometers, aren't we?

[kerbiloid]

If a space pirate has a hook glove and a jetpack, he doesn't need long tethers.

He can be maneuvering, grappling the objects and bring them to his ship by the hook, then catch the tether with another hand.

Also the glove hook can be extendable and use its own thin cable, to pull the pirate to the aim, grappled by the hook. Also it can be shot.

[Shpaget]

SpinLaunch seems to have signed some sort of deal with NASA to yeet a 3 meter long payload on a suborbital test at about Mach 2. Landing using a parachute.

Mach 6 test later this year.

https://techcrunch.com/2022/04/06/spinlaunch-scores-nasa-test-mission-to-demonstrate-its-unique-launch-method/?guccounter=1&guce_referrer=aHR0cHM6Ly9lbi53aWtpcGVkaWEub3JnLw&guce_referrer_sig=AQAAAJnLpVqzVWpYhVVxUdk6m6ZzJ_vcqB7-DtOxclaLBRDSVD9HHRWWgEsvQpO4VDu7l0hbgqh0gqLphklv9Kd_fozgEgk0j-1217Wo6u0CXNTJJw76VSHB5MEZkwCd0R4mbheHM0m8tKl4Bq9PKCzuG5QsIv0TwjMIxCc1G80aX2Zm

 

[darthgently]

20 minutes ago, Shpaget said:

SpinLaunch seems to have signed some sort of deal with NASA to yeet a 3 meter long payload

Of all the ways one might deorbit space junk I think small targeted "deorbiters" via something like SpinLaunch might actually be by far the most feasible from a financial POV.  The payloads wouldn't need to be very big and would never be manned or have fragile payloads so the acceleration would never be an issue (if deorbiters were designed right).   If SpinLaunch could be deployed on a repurposed container ship for example they could have hundreds, if not thousands, of "deorbiters" in storage and take their time launching from various latitudes to match targeted orbits of debris with much less need to change planes in orbit as often

Edited April 15, 2022 by darthgently

[darthgently]

On 12/7/2021 at 8:24 PM, sevenperforce said:

Satellites are small and space is big. It’s not a significant issue. 

Most orbital skyhook designs utilize relatively low orbital paths with solar-electric propulsion modules at each end and at the center of mass. 
 

I can't imagine the advances in materials science required to make a sky hook work in something like Earth's atmosphere and weather.  Hurricanes would wreak havoc on a skyhook

[JoeSchmuckatelli]

3 minutes ago, darthgently said:

I can't imagine the advances in materials science required to make a sky hook work in something like Earth's atmosphere and weather.  Hurricanes would wreak havoc on a skyhook

The harmonics alone... 

Back to the space Elevator I wonder what frequency it would vibrate at (and whether the earth would sing) 

Edited April 15, 2022 by JoeSchmuckatelli

[darthgently]

Skyhooks and elevators make a lot more sense on bodies without atmospheres.   Feasible

[wumpus]

Scott Manley had an interesting comment that the "paper" spinlaunch launch vehicle is roughly same size as Rocket Lab's Electron, and rough the same payload.  But anything spin launch compatible needs to handle the g-forces.  The tradeoff between rocket engines and heat shields doesn't seem to be a good one.

He repeated that he didn't think that physics was Spinlaunches big problem.  They will likely have far more economical ones.  Granted, both fall under the category of "engineering".

[StrandedonEarth]

On 4/15/2022 at 10:05 AM, darthgently said:

I can't imagine the advances in materials science required to make a sky hook work in something like Earth's atmosphere and weather.  Hurricanes would wreak havoc on a skyhook

I didn't think Skyhooks were supposed to reach that low? Perhaps as low as 30 miles, well above the weather?  Wiki says 100km or higher...

https://en.wikipedia.org/wiki/Skyhook_(structure)

[sevenperforce]

7 hours ago, StrandedonEarth said:

On 4/15/2022 at 1:05 PM, darthgently said:

I can't imagine the advances in materials science required to make a sky hook work in something like Earth's atmosphere and weather.  Hurricanes would wreak havoc on a skyhook

I didn't think Skyhooks were supposed to reach that low? Perhaps as low as 30 miles, well above the weather?  Wiki says 100km or higher...

https://en.wikipedia.org/wiki/Skyhook_(structure)

Yes, correct. Skyhooks don’t come down to the surface by any means. And you spin the skyhook end-over-end in the same direction as the orbit, so the end that enters the atmosphere is moving quite slow compared to orbital velocity. 

[darthgently]

Test launch, supersonic

Edited April 19, 2022 by darthgently

[HebaruSan]

A tour of the facility and review of some technical details:

Notables:

• Carbon fiber everywhere
• Their vacuum chamber is cheaper because they only need one-millionth the depressurization of typical aerospace vacuum chambers that need space-like conditions rather than just a lot less drag and heating
• The plans call for a one-way fast airlock at the exit to protect the still-spinning tether from atmospheric pressure, and they demonstrated how the inner door would slam shut as soon as the payload passes it
• They're releasing a counterweight simultaneously to keep the rig balanced after launch, but they hope to replace this with another payload fired right after the first as the opposite arm reaches the exit
• Regenerative braking of the tether after launch (planned)
• Deceleration from drag expected to be about 2 g when it hits the air, 1 g 5 seconds after that. 0.2 g after 15 seconds; total drag losses projected to be 150 m/s
• They're reluctant to reveal anything about the release mechanism, supposedly so they can patent it

[magnemoe]

3 hours ago, HebaruSan said:

A tour of the facility and review of some technical details:

Notables:

• Carbon fiber everywhere
• Their vacuum chamber is cheaper because they only need one-millionth the depressurization of typical aerospace vacuum chambers that need space-like conditions rather than just a lot less drag and heating
• The plans call for a one-way fast airlock at the exit to protect the still-spinning tether from atmospheric pressure, and they demonstrated how the inner door would slam shut as soon as the payload passes it
• They're releasing a counterweight simultaneously to keep the rig balanced after launch, but they hope to replace this with another payload fired right after the first as the opposite arm reaches the exit
• Regenerative braking of the tether after launch (planned)
• Deceleration from drag expected to be about 2 g when it hits the air, 1 g 5 seconds after that. 0.2 g after 15 seconds; total drag losses projected to be 150 m/s
• They're reluctant to reveal anything about the release mechanism, supposedly so they can patent it

Not having aerospace vacuum chamber makes obvious sense, your are reducing drag not emulating space to test for vacuum welding 

With the counterweight I assume the other side also reach the wall unlike shown in this preview shot. Have two rails close to the sidewall, this run outside the hole for the  exit tube.
Lift counterweight a cm above the rail and spin up. release the payload and the counterweight, the counterweight is still connected to the bar.
You could magnets here to brake.

Recover the aerodynamic shell like falcon 9 fairing? 

You still have the rotation of the payload after release but with you might be able to cancel out some of this releasing the front attachment first? 
For an fast closing door, well how about an rotating dish with an oval hole in it? You would want an second door for an good seal but that could be slower, Not that they uses however. 

 

[JoeSchmuckatelli]

I look at that - and I'm reminded of the problems with commercially viable Tesla Turbines; supersonic RPM and materials science.

[wumpus]

3 hours ago, JoeSchmuckatelli said:

I look at that - and I'm reminded of the problems with commercially viable Tesla Turbines; supersonic RPM and materials science.

Don't forget the scaling issues.  Scale it down and your aero drag increases, meaning even more mass for you heatshield.  Scale it up and all your materials strength issues get worse (mostly in the launcher).  I think at some point Scott Manley was talking about this and noted that the heat shield needed for spin launch was similar in mass to the electron rocket (not sure which stages he was talking about), which might make the initial system pretty useless (depending on the cadence they get).

And don't forget all the g-forces on your rocket that you would get in an equally long cannon/railgun to orbit, only sideways.

I think the real issue is the timing.  They need a huge cadence, but since they have such a small launcher they aren't likely to make a profit sending less g-sensitive stuff (fuel?) to orbit en mass.  I'd have to assume that now is the moment to strike (any later and they wouldn't be able to bootstrap their way to a larger launcher), but it still doesn't seem like there ever was going to be a window for this type of thing.

[Gargamel]

On 8/6/2022 at 11:59 AM, HebaruSan said:

A tour of the facility and review of some technical details:

Watched that today, and it's quite a love song for the system.   It really turned my opinion around from cautious skeptic to "hey, maybe this really can work".    It's long, but worth the watch.  They do cover quite a few of the details that we've gone back and forth over here. 

[StrandedonEarth]

 

[Shpaget]

1U cubesat!*

*May violate mass guidelines.

 

Four years to build the big yeeter? Good luck, I suppose.