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Rocket Labs mean business, Brits stick pin in Mars map, and Japan celebrates HTV-7’s dive into the atmosphere

Neil Barnes Silver badge
Alien

penetrating two metres into the surface of the red planet in search of signs of life.

"You bastard, that *hurt*. Earth-shattering kaboom time, I think."

cray74 Silver badge

Hippy-friendly hybrid-electric rocket motors

I'm still boggling at the use of electric turbopumps on the Rocket Lab's Electron, but if you only need 1 megawatt (those 9 engines are tiny) for about 2 minutes then that's about 33kWh and not too bad.

The engineering and development advantages are interesting. You entirely eliminate all the turbomachinery of the fuel pumps, so that makes development easier. You're not diverting propellant to run turbines, so the engine can gain efficiency without the plumbing complications of a staged combustion engine.

The drawback is a heavy battery pack, but it'll be lighter than an electric car's because you don't care about reusability and good recharging characteristics.

I wonder how electric pumps would scale to larger rockets that use turbopumps in the tens of megawatts.

Vulch

Re: Hippy-friendly hybrid-electric rocket motors

The pumps use a number of battery packs and as each one is depleted it is jettisoned, lightening the load.

asphytxtc

Re: Hippy-friendly hybrid-electric rocket motors

> I wonder how electric pumps would scale to larger rockets that use turbopumps in the tens of megawatts.

Short answer is, they just don't.. Specific energy of the power source, and weight of the machinery, are going to be hugely limiting factors. The energy density of say RP-1/LOX is just so much better and turbopumps just produce a massive amount of power given their relative weight, something no electric motor can come close to as it scales up, using any current or projected technology.

Rutherford made a great choice using electric for the Electron, it hugely simplifies the engine design (and probably hugely increases reliability to boot) but electrically driven engines will never be more efficient than a more traditional turbopump driven engine.

The gains here are in simplicity, not efficiency, basically.

cray74 Silver badge

Re: Hippy-friendly hybrid-electric rocket motors

and as each one is depleted it is jettisoned

Cool, I didn't know that.

Semtex451 Silver badge
Unhappy

Blighty picks a nice spot for a picnic on Mars

I'm still crying over Beagle2

David Nash Silver badge

120 launches a year?

Seems optimistic?

moooooooo

Re: 120 launches a year?

they're actually aiming for one per week. Their license is actually for one every 72 hours.

Keith Oborn

Ooh err missus--

"Rocket Labs launched six satellites into the nether"

So they've reached Uranus then?

Sorry-

Alister Silver badge

Re: Ooh err missus--

Bloody stupid computer autocorrect that doesn't recognise the word ether.

AI - yeah, right...

Jan 0

Re: Ooh err missus--

> Bloody stupid computer autocorrect that doesn't recognise the word ether.

Maybe it's clever enough to realise that you weren't writing about an organic reagent, but not clever enough to think you meant "æther".

marknzl

Business Socks

No comments on the Flight of the Concords reference?

Sorry that handle is already taken. Silver badge

Re: Business Socks

I was expecting the mission name to link to youtube. Missed opportunity Reg!

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