Quote from: TrevorMonty on 07/10/2018 07:39 pmWatch video. Launches to 500km SSO from Vandenburg, probably as secondary payload.At 585Kg it could do future launches on new small LVs eg Firefly and Relativity. To big for Launcherone.With landed mass about 185kg (burns over 400kg fuel) should be able to deliver reasonable size payload.Which video?400/585 is not a high enough prop mass fraction to get to the lunar surface from SSO. It would need to be sent considerably higher by the LV, at least to GTO apogee.
Watch video. Launches to 500km SSO from Vandenburg, probably as secondary payload.At 585Kg it could do future launches on new small LVs eg Firefly and Relativity. To big for Launcherone.With landed mass about 185kg (burns over 400kg fuel) should be able to deliver reasonable size payload.
Quote from: envy887 on 07/10/2018 07:46 pmQuote from: TrevorMonty on 07/10/2018 07:39 pmWatch video. Launches to 500km SSO from Vandenburg, probably as secondary payload.At 585Kg it could do future launches on new small LVs eg Firefly and Relativity. To big for Launcherone.With landed mass about 185kg (burns over 400kg fuel) should be able to deliver reasonable size payload.Which video?400/585 is not a high enough prop mass fraction to get to the lunar surface from SSO. It would need to be sent considerably higher by the LV, at least to GTO apogee.Read article and watch video.www.bbc.co.uk/news/world-middle-east-44777305As we now know its going from florida as secondary on F9. Seems like lander is flexible on depart orbits, SSO or GTO.
Quote from: TrevorMonty on 07/11/2018 10:13 amQuote from: envy887 on 07/10/2018 07:46 pmQuote from: TrevorMonty on 07/10/2018 07:39 pmWatch video. Launches to 500km SSO from Vandenburg, probably as secondary payload.At 585Kg it could do future launches on new small LVs eg Firefly and Relativity. To big for Launcherone.With landed mass about 185kg (burns over 400kg fuel) should be able to deliver reasonable size payload.Which video?400/585 is not a high enough prop mass fraction to get to the lunar surface from SSO. It would need to be sent considerably higher by the LV, at least to GTO apogee.Read article and watch video.www.bbc.co.uk/news/world-middle-east-44777305As we now know its going from florida as secondary on F9. Seems like lander is flexible on depart orbits, SSO or GTO.Direct video link (from 2015) However, the prop mass fraction give is not enough. With storable props, 400 kg will only give ~3,600 m/s and it needs about 6,000 m/s from SSO. The difference is almost exactly a GTO insertion, about 2,500 m/s. Either it needs more propellant, or the upper stage to restart and put it in higher orbit. The 40,000 km apogee first phasing orbit described in the video would be perfect.
Quote from: TrevorMonty on 07/10/2018 07:39 pmWatch video. Launches to 500km SSO from Vandenburg, probably as secondary payload.Do you mean this video? The one that shows Sparrow deploying from the base of the second stage! I wouldn't trust anything that video shows. By the way, best of luck to SpaceIL on the landing attempt, but they'll need India to fail with Chandrayan 2 this October in order to be fourth, otherwise Israel will end up fifth if India succeeds.
Watch video. Launches to 500km SSO from Vandenburg, probably as secondary payload.
If you want to last as long as possible during the lunar day (meaning 14 Earth days) you want to land as soon as is feasible after sunrise. For a given landing site there will be just a day or two in each month when the illumination is right for a landing. The moment of sunrise is probably not ideal, more likely they would be planning to land 10 or 20 hours after sunrise. Map that to a specific site and you have your need for precision (not a few seconds, obviously, I think that's just for dramatic effect). The sites being considered as of 18 months ago were described here:https://www.hou.usra.edu/meetings/lpsc2017/pdf/1914.pdf(LPSC abstract)Considering lighting, this might suggest the Wohler site for that date. Note that the Reiner Gamma site from the 2015 video shown above does not meet their thermal requirements now.
Bridenstine also met with SpaceIL, the former Google Lunar X Prize team that is continuing to develop its lander even though the prize purse expired in March. SpaceIL announced July 10 that it is planning to launch its lunar lander as a secondary payload on a SpaceX Falcon 9 in December, deploying into a supersynchronous transfer orbit that it will gradually raise until it can maneuver into lunar orbit. SpaceIL said their planned landing date is Feb. 13, 2019.
A Supersynchronous Transfer Orbit (STO) is not the same as a Sun-Synchronous Orbit (SSO). A STO is a type of GTO where the apogee goes beyond the GEO altitude.
This is a good example of why certain people (like Musk) hate acronyms.