[AR] Re: hydrogen and oxygen propellant produced on Mars
- From: Ken Hollis <gandalf@xxxxxxxxxxx>
- To: arocket@xxxxxxxxxxxxx, Arocket List <arocket@xxxxxxxxxxxxx>
- Date: Tue, 20 Jun 2017 16:25:04 -0700 (GMT-07:00)
Greetings and Salutations:
From: Henry Spencer <hspencer@xxxxxxxxxxxxx>
On Tue, 20 Jun 2017, John Dom wrote:
As for returning to Earth will the H2 & O2 propellant produced in situ
require liquefaction (cooling) in its tanks on Mars? Or could the gaseous
state Isp suffice?
Gaseous-state Isp is potentially actually slightly better, because there's
a bit more thermal energy in the propellants at the start. The problem is
the terribly low density, which makes for poor engine T/W and impossibly
heavy tanks. A one-cubic-meter tank holds about 70kg of LH2, but even at
1500psi, only about 8kg of GH2 at 25degC.
Is it a consideration to use Hydrogen Fusion instead of a chemical rocket? With
Hydrogen fusion you may need quite a bit less.
NASA paper (I know, it is a theoretical) says that gives better Isp than
chemical, see:
https://1drv.ms/f/s!AsoLDJx_szsuj_EcIUsz3h-5kO3wHg
NASA Paper --> Fusion_Driven_Rocket_716077main_Slough_2011_PhI.pdf
From what I can tell the fusion products from Hydrogen do not leave radioactive
debris.
Ken
Other related posts:
