Ivan:
What battery technology is favored here? Thermal batteries can provide a
lot of power for a minute or two, but are expensive. Is some lithium
chemistry the best choice? Or are these a combination of a battery and a
super-capacitor?
Bill
On Thu, Jul 8, 2021 at 12:52 AM Ivan Vuletich <ivan.vuletich@xxxxxxxxxxxx>
wrote:
My understanding is that electric pumps make sense on a smaller rocket.
You trade the expense of developing a small turbo pump for the expense of
developing a custom high power battery pack, which for RocketLab was a
better problem to have.
Mass wise, the engine minus the batteries is pretty light, I've picked up
a prototype with one hand. According to wiki, the dry weight of the engine
is 35 kg, I'm pretty sure that is without the batteries.
https://en.wikipedia.org/wiki/Rutherford_(rocket_engine)
One advantage of batteries is their modularity, if you take a look the
1:03 mark in the video, you can see a pair of 2nd stage batteries being
jettisoned during the 2nd stage burn.
https://www.youtube.com/watch?v=7OepuqFfUdk
Ivan
On 8/07/2021 9:33, William Claybaugh wrote:
That’s an interesting topic:
Why do electric pumps make sense? Is it smaller rockets only? Do they
need thermal batteries to get sufficient power? Do they save money on
operating costs or just on development and production?
Bill
On Wed, Jul 7, 2021 at 5:27 PM David Arnold <davida@xxxxxxxxx> wrote:
And as for rockets -- remember them? :-) -- electric and hydrogen havetheir niches, especially in space. For ordinary launchers, though, sure
looks like LOX/hydrocarbon is the way to bet (with the caveat, again, that
the hydrocarbons might eventually be biofuels or synfuels).
RocketLab’s electric pumps might be said to constitute a “hybrid”
approach?
d
