Quote from: DreamyPickle on 11/11/2020 12:06 amWithout veering into politics: would it be possible to review or cancel the gateway and keep the rest of Artemis, meaning SLS and HLS?Plans were already made to land without the gateway and it's not clear if any of the HLS participants require it.There are already several international partners, so pretty unlikely I guess
Without veering into politics: would it be possible to review or cancel the gateway and keep the rest of Artemis, meaning SLS and HLS?Plans were already made to land without the gateway and it's not clear if any of the HLS participants require it.
If NASA had an HLS with enough delta-v in the works (like Constellation's 'Altair') they would not need a Gateway station at all. If Orion met a Lander in the Halo orbit that was 'fat with propellant', the crew could transfer to that and get down to the lunar surface. Perhaps the 'National Team' design with a big enough transfer element would fit the bill?However; such a beast would have to get out to the Halo orbit in three launches of Commercial rockets. Taking another SLS launch out of the critical path of the mission architecture would be a good thing. 2x launches of Vulcan-Centaur V with 6x solid motors could probably get that Lander out to the Moon. Or 1x Falcon Heavy and 2x Atlas V's.Also; without a Gateway, it would be difficult to implement a reusable Lander. So perhaps, at least the first two missions would have to use an expendable Lander?
If NASA had an HLS with enough delta-v in the works (like Constellation's 'Altair') they would not need a Gateway station at all. If Orion met a Lander in the Halo orbit that was 'fat with propellant', the crew could transfer to that and get down to the lunar surface.
... without a Gateway, it would be difficult to implement a reusable Lander.
That's not much of an advantage. You are better building redundant habitats on the Moon. In my view, the main advantage of Gateway is that it is its own destination, just like the ISS is.
Quote from: MATTBLAK on 11/11/2020 12:59 amIf NASA had an HLS with enough delta-v in the works (like Constellation's 'Altair') they would not need a Gateway station at all. If Orion met a Lander in the Halo orbit that was 'fat with propellant', the crew could transfer to that and get down to the lunar surface.The plan is to build an HLS with the delta-V to go between the halo orbit and the lunar surface, isn't it? The lander might have a single stage (SpaceX's Starship derivative) or two or three, but it would have the delta-V to take a crew from a halo orbit to the lunar surface and back.Quote... without a Gateway, it would be difficult to implement a reusable Lander.Why? While parked in a halo orbit, the lander needs to maintain thermal and attitude control and do some station keeping. Maybe docking it to a gateway helps with that, but it's really not obvious to me that a gateway is terribly valuable.My understanding of the value of a gateway is that it can mitigate one of the drawbacks of halo-orbit staging, namely the infrequent opportunities for return to Earth. Unlike LLO staging with adequate delta-V, staging in halo orbit may require a wait of several days before a trans-Earth window opens. In that case, a gateway station might serve as a backup for keeping a crew alive.
Gateway isn’t needed at all for the Moon.Gateway exists because of Mars. It’s a prototype Mars Transfer Vehicle, and the main reason to stage a lander from Gateway is it’s operational practice for doing the same thing at Mars.
Quote from: Robotbeat on 11/13/2020 08:47 pmGateway isn’t needed at all for the Moon.Gateway exists because of Mars. It’s a prototype Mars Transfer Vehicle, and the main reason to stage a lander from Gateway is it’s operational practice for doing the same thing at Mars.Your reason for Gateway is the first one that makes any sense to me. I don’t remember seeing it in print anywhere. Have you? If so please provide source.
Isn't the PPE derived from the asteroid redirect mission?
Quote from: DreamyPickle on 11/14/2020 09:16 pmIsn't the PPE derived from the asteroid redirect mission? Yes, it is.
Google deep space transport. It would be tested at Gateway.
Question: Have we seen a Gateway Systems Operations & Maintenance line item estimate yet?Note: I'd ask the person who posted the billion per year figure in a different media outlet's comment section directly for a source but he isn't talking to me because politics. If that isn't a made up figure I definitely have an NSF worthy opinion to post.
Quote from: RonM on 11/14/2020 12:49 amGoogle deep space transport. It would be tested at Gateway.Yes. Lunar Gateway is the former Deep Space Habitat with a new name tag slapped onto it.