This is strangely enough related to Gateway:https://twitter.com/ninjaneergirl/status/1521140828759986177
When we looked for the proper orbit for @NASA_Gateway, we were fortunate to have options. We could go high or low, but what if we could have the best of both, where we had both easy surface access and fuel efficiency? Enter the near-rectilinear halo orbit...
A spacecraft in low lunar orbit follows a circular or elliptical path very close to the lunar surface, completing an orbit every two hours. Transit between Gateway and the lunar surface would be quite simple in a low lunar orbit given their proximity, but because of the Moon’s gravity, more propellant is required to maintain the orbit. Therefore, low lunar orbit is not very efficient for Gateway’s planned long-term presence at the Moon – at least 15 years.
I think that NASA's argument is that they didn't want to put Gateway in LLO anyways because it would require too much propellant to maintain it there.
Quote from: yg1968 on 05/24/2022 12:21 amI think that NASA's argument is that they didn't want to put Gateway in LLO anyways because it would require too much propellant to maintain it there.The mascon issue becomes negligible above 100km, vice the 3000km to 70000km Gateway altitude on its NRHO. Even below 100km, there are frozen lunar orbits at four inclinations where mascon and other effects cancel each other out. IIRC, there is even one around 85 degrees that passes over the poles.
What struck me most about this strange presentation of the Lunar Gateway is that Northrop Grumman decided to copy my rendering of an internal Russian lunar lander concept that I created for Popular Mechanics around 2015. Try find differences: https://russianspaceweb.com/lvpk.html
The Capstone mission might be in jeopardy after launch. Communication died not long after separating from its launcher. I hope for the best, but I bring this up here because the mission was largely meant to test the orbit Gateway might occupy.
Quote from: redliox on 07/05/2022 07:04 pmThe Capstone mission might be in jeopardy after launch. Communication died not long after separating from its launcher. I hope for the best, but I bring this up here because the mission was largely meant to test the orbit Gateway might occupy.Update for CAPSTONE. Apparently communication is restored, although the cause of the outage hasn't been determined yet.
the spacecraft operations team attempted to access diagnostic data on the spacecraft’s radio and sent an improperly formatted command that made the radio inoperable. The spacecraft fault detection system should have immediately rebooted the radio but did not because of a fault in the spacecraft flight software.CAPSTONE’s autonomous flight software system eventually cleared the fault and brought the spacecraft back into communication with the ground, allowing the team to implement recovery procedures and begin commanding the spacecraft again.
Another day at the office, this time looking at the structure for HALO getting welded with NASA's Jim Free, including a look through the CBM hatches... I've tapped it now a couple dozen times when clocking in every morning https://mobile.twitter.com/NASA_Gateway/status/1549490404697014275https://mobile.twitter.com/JimFree/status/1549460016402276353
Another day at the office, this time looking at the structure for HALO getting welded with NASA's Jim Free, including a look through the CBM hatches... I've tapped it now a couple dozen times when clocking in every morning
Given the news today of the Russians leaving the ISS and the more recent articles stating that an ISS replacement won't be ready by 2030, would it be time to re-evaluate whether the Lunar Gateway in a NRHO orbit makes sense? Instead could you just put it into LEO, and have it be a staging point for Lunar missions from there? That way we could use the Crew Dragon and Starliner to get astronauts there. I searched around on this forum before asking this and a lot of the posts on the Gateway are hostile. Also included a link to a debate b/w Robert Zubrin and Greg Autry which is an interesting watch. I'm just wondering the Gateway in LEO if this is a viable alternative or if keeping it in NHRO is still a better option. Or would another option be to just ad more modules to the Gateway in NRHO and have people there full time starting around 2030 when the ISS reaches its end of life?