Author Topic: Long term storage of LOX and LCH4 in orbit  (Read 9067 times)

Offline TrevorMonty

Re: Long term storage of LOX and LCH4 in orbit
« Reply #60 on: 07/04/2018 01:16 AM »
I'd have thought you would want the station higher, not lower, so that it requires less station keeping fuel. But I suppose if launch costs plummet, you expect station keeping fuel to be cheap.

Lower depot orbit more fuel something like BFR can deliver per launch. The difference between 500km and 250km for BFR could be few tons. Ideally lot more than extra station keeping fuel needed between launches. Higher flight rate lower orbit can be.

There is no reason depot can't vary its orbit depending on demand. If there are no fuel deliveries for few months, then raise its orbit.






Offline johnfwhitesell

  • Full Member
  • ***
  • Posts: 306
  • Liked: 97
  • Likes Given: 193
Re: Long term storage of LOX and LCH4 in orbit
« Reply #61 on: 07/04/2018 11:59 AM »
Lower depot orbit more fuel something like BFR can deliver per launch.

Lower also means you need more fuel to get to GTO.

Online LMT

  • Lake Matthew Team
  • Full Member
  • ****
  • Posts: 470
    • Lake Matthew
  • Liked: 50
  • Likes Given: 0
Re: Long term storage of LOX and LCH4 in orbit
« Reply #62 on: 07/04/2018 12:46 PM »
I'd have thought you would want the station higher, not lower, so that it requires less station keeping fuel...

...250km...extra station keeping fuel needed...

ISEP is station-keeping without fuel, or rather, propellant.  ISEP kN thrust would enable long-term fleet storage of LOX and LCH4 in equatorial VLEO. 

The article authors see benefits in an equatorial LEO waystation.  For example:

Quote
"Since the equatorial location offers simple ascent and reentry operations with minimal propellant expenditures and a low-radiation in-orbit environment for humans, this solution could really catch on."

The authors overlooked ISEP when making their case for a LEO waystation, but we see how ISEP gives that case an extra boost [pun].

--

Or we could ignore ISEP.  But I think a forum devoting 11 threads to the so-called "EmDrive" should welcome the straightforward physics of F=BIL.   ::)
« Last Edit: 07/04/2018 01:49 PM by LMT »

Tags: