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Rocket Launch in New Zealand Brings Quick, Cheap Space Access

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Re: Rocket Launch in New Zealand Brings Quick, Cheap Space Access

#71

Post by dtkav »

gok wrote: post #55

Very cool, but is there really a future for tiny expendable rockets in a world of big reusable ones?

IMHO it's a slightly different market. Dedicated launch allows you to do things like replenish an existing constellation, or go to weird orbits, because you have a say over where the rocket is going. Also it removes a big coordination overhead, and could be more "on demand".

Then again, a reusable rocket on a regular cadence to sun-synchronous orbit could probably serve the earth-imaging market pretty effectively.

Re: Rocket Launch in New Zealand Brings Quick, Cheap Space Access

#72

Post by masklinn »

baybal2 wrote: post #43
rsynnott wrote: post #40

Earlier quoted context omitted.

They probably mean hydrazine. The Russian Proton rocket uses it, though it’s being discontinued. This isn’t a uniquely Russian oddity, by the way; the European Ariane IV and US Titan IV were still in use into the last decade.

UDMH is not hydrazine, and is said to be worse as it doesn't biodegrade as readily as hydrazine. UDMH, hydrazine, and MMH are all very different beasts.

UDMH and MMH are both hydrazine derivatives, classified as hydrazines, and either picked or mixed (Aerozine 50 is a 50/50 mix of hydrazine and UDMH) depending on the specific chemical and performance tradeoffs you want to make.

UDMH, hydrazine and MMH are slightly different beasts.

Re: Rocket Launch in New Zealand Brings Quick, Cheap Space Access

#73

Post by rocqua »

2trill2spill wrote: post #52

My favorite thing about Rocket Lab is the rocket engine they use[1]. By replacing the turbopump with a electric motor they were able to remove one of the single most complicated and expensive parts of a rocket engine. As battery densities keep increasing we should see electrically fed engines being used on bigger and bigger rockets. [1]: https://en.wikipedia.org/wiki/Rutherford_(rocket_engine)

As I recall, it remains the case that rocket engines get worse performance with an electric fuel pump.

Electric has two issues. First of all, the energy density (after controlling for efficiency of electric motors / turbo pumps) is lower than that of rocket fuel. Second of all, an empty battery weighs as much as a full one, whereas used fuel no longer weighs down the rocket.

Re: Rocket Launch in New Zealand Brings Quick, Cheap Space Access

#74

Post by wolf550e »

rocqua wrote: post #73
2trill2spill wrote: post #52

My favorite thing about Rocket Lab is the rocket engine they use[1]. By replacing the turbopump with a electric motor they were able to remove one of the single most complicated and expensive parts of a rocket engine. As battery densities keep increasing we should see electrically fed engines being used on bigger and bigger rockets. [1]: https://en.wikipedia.org/wiki/Rutherford_(rocket_engine)

As I recall, it remains the case that rocket engines get worse performance with an electric fuel pump. Electric has two issues. First of all, the energy density (after controlling for efficiency of electric motors / turbo pumps) is lower than that of rocket fuel. Second of all, an empty battery weighs as much as a full one, whereas used fuel no longer weighs down the rocket.

They disconnect and dump the battery mid-flight on ascent to not carry the mass of the empty battery, which might be counted as half a stage in rocket terminology (like https://en.wikipedia.org/wiki/SM-65_Atlas)

See: https://www.youtube.com/watch?v=sPwMuUxSrcA&t=1625

Re: Rocket Launch in New Zealand Brings Quick, Cheap Space Access

#76

Post by greglindahl »

curuinor wrote: post #61
peatmoss wrote: post #2

The years I spent in New Zealand painted a vivid picture of a society of doers. I think there’s something to the idea that this comes in part from being a landmass the size of Colorado, with not much more than 4 million people, with the freedom and requirements to maintain the infrastructure of being a sovereign nation. Seeing a NZ rocket launch condures an image of a small group of doers dreaming big. Way to go NZ!

Wait, isn't Rocket Lab an american company, and they're just locating the rocket in NZ? Founders were Kiwis but HQ is in California...

The rocket uses a fair amount of ITAR-restricted technology, which means that they needed a pretty robust US-based organization and engine manufacturing. The company also sold a bunch of suborbital rocket launches to the US government before they raised money to build an orbital rocket. And the money mostly came from US-based VCs. All of these details feed into the company HQ being in the US, but a majority of their employees appear to be in NZ.

Re: Rocket Launch in New Zealand Brings Quick, Cheap Space Access

#77

Post by devindotcom »

FlyingSideKick wrote: post #75

While this is fantastic news on one hand, it is concerning that cheap launches will lead to so much debris in low earth orbit that future generations will find it difficult to orbit without significant risk of micrometeorite strikes.

Rocket Lab is being pretty good about this. Their rocket designs are super low waste compared with older ones. It's one of Peter Beck's pet issues.

Re: Rocket Launch in New Zealand Brings Quick, Cheap Space Access

#78

Post by Kye »

Gravityloss wrote: post #59
village-idiot wrote: post #22

The most impressive thing about their rockets are the motors they use. All modern liquid rocket motors use turbo pumps to pressurize liquid fuel and drive it into the combustion chamber. All other rockets use some fuel to run a turbine that powers the pumps, with the variations being how that entire system is piped together. The Rocket Lab motor, Rutherford, uses a lithium ion battery and electric motor to power the…

A fuel burning turbine is much more mass efficient than a lithium battery powered one. And hence also makes the whole vehicle more fuel efficient. But a turbine is much harder to develop and manufacture. Especially at small scale, the turbine is also inefficient so it has less advantage to a battery there. It wouldn't make sense to run the Falcon 9 pumps with batteries.

I wonder how a hybrid approach like they do with freight trains would work. Generate electricity with energy-dense fuel, then use that to drive electric motors.

Re: Rocket Launch in New Zealand Brings Quick, Cheap Space Access

#79

Post by Kye »

breischl wrote: post #26
Waterluvian wrote: post #16

Earlier quoted context omitted.

I just had a daydream of Satellites as a Service. "give us a docker image extending our base image, no larger than x MB delta, and we will run it on a chosen satellite for a certain time slice for $y" I can see that future. Even if purely as a learning tool for students.

Would the satellites have some known set of sensors or something like that? Just trying to figure out what would be the point, other than just the coolness of running code in spaaaaaaaace.

Raspberry Pi In The Sky

Re: Rocket Launch in New Zealand Brings Quick, Cheap Space Access

#80

Post by Kye »

SEJeff wrote: post #23
pferde wrote: post #12

Earlier quoted context omitted.

Hopefully, soon it will be "just another AZ".

How would you name that? space-west-1? Cardinal directions are sort of irrelevant.

A formula describing its path across the latitude/longitude graph.
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