Quote from: Lee Jay on 04/16/2023 09:39 pmThe Scott Manley video on this has a really interesting tidbit."...I'm going to be getting on a plane to fly out in that direction, but I'm not going there. Believe it or not there's something cooler that I have to go to. I can't tell you what it is."WTH?If it’s cooler than the first Super Heavy launch, it better involve space aliens
The Scott Manley video on this has a really interesting tidbit."...I'm going to be getting on a plane to fly out in that direction, but I'm not going there. Believe it or not there's something cooler that I have to go to. I can't tell you what it is."WTH?
I'm an avid NSF content consumer. But I don't think any other content provider will deliver what Ellie delivered in this video; an interview with the Brownsville mayor involved in the entire journey of SpaceX in Boca Chica. And the mayor has a heartfelt recognition of what Starship means to her community and to the world (and to her son :-) Very much worth a view.
Quote from: oiorionsbelt on 04/16/2023 06:17 pmLooking at the SpaceX test flight timeline.Anyone know why the ships fuel/methane load starts before the LOX load? The boosters LOX loading and methane loading start at the same time.Just went to the SpaceX website to look at the timing. (Fueling is about 1 hour, if you want to watch the excitement build)Why is the flight diagram so god awful?Booster flies back, and only then performs the flip and then boost-back burn?Then it flies back, changes its mind, flies forward again (so why not just fly forward to begin with?)What's happening?
Looking at the SpaceX test flight timeline.Anyone know why the ships fuel/methane load starts before the LOX load? The boosters LOX loading and methane loading start at the same time.
I am shocked there hasn’t been more coverage about this but maybe that is by design with a late Friday approval and announcement. Keep it quiet in case of RUD.
I know it’s the first launch attempt and many things could happen to prevent liftoff.
Quote from: wannamoonbase on 04/16/2023 10:59 pmI know it’s the first launch attempt and many things could happen to prevent liftoff. Look for a local yokel in a boat that scrubs the launch.
Quote from: sebk on 04/16/2023 12:53 pmQuote from: edzieba on 04/15/2023 02:27 pmQuote from: sebk on 04/15/2023 01:44 pmNope. You are totally wrong.To have perigee below sea level and be able to do 3/4 of the circle around the Earth after standard rocket launch (Space-guns, X-30 NASP-like spaceplanes or other Sci-Fi solutions notwithstanding) you must have apogee at ~320km or higher. Otherwise your trajectory would be too shallow. Wrong. Impossible for a pure impulsive launch (e.g. space gun) but not for any real launch vehicle, which has tens of minutes of burn time, and outside the atmosphere can vector thrust arbitrarily. Whilst eccentricity and plane changes performed within the burn to orbit are expensive in terms of delta V, physics will not stop you. You can - for example - insert directly into an orbit with an apogee above your current altitude and descending, and thus never reach apogee.Wrong. As I wrote, this applies to everything behaving like a rocket. In fact, it'd be more doable with a space gun (realistically it must be either some type of EM gun or nuclear) than with a rocket: guns always have perigee below ground level, you must raise it later. And no rocket burns for tens of minutes. The longest ascent burns approaches 20m and it takes less than 1/10 of the full circle to ascent. Way too little to cut the exoatmospheric part of the flight below half circle which would be required to play games with lowering perigee without raising apogee.And yes, you can insert into an apogee of an orbit, that's not a problem at all (and rockets without upper stage restart capability did this in the past). The thing is, you can't then have the perigee not only under ground but even in the significant atmosphere (i.e. below 90km) and do a 270° around the Earth. If you wanted to go for less than half circle, then you're free to do so. But with 270° flight you're limited by the reality that perigee is necessarily 180° from the apogee. If you insert to an overhead apogee, your perigee will be at the antipode of your launch site, 180° away. Obviously, you're not doing 270° if your perigee is only 180° away and underground. It must be above the ground, and significantly at that.The way to have the lowest perigee (if this is your particular goal; it's not even Starship goal to begin with) while keeping apogee below the set level (235km here) is to have it roughly half-way between your splashdown/landing site and your launch site (give or take 5°). Apogee then must be about half way of your flight.Too many mental gymnastics going on in this thread. It is a suborbital ballistic trajectory, period.
Quote from: edzieba on 04/15/2023 02:27 pmQuote from: sebk on 04/15/2023 01:44 pmNope. You are totally wrong.To have perigee below sea level and be able to do 3/4 of the circle around the Earth after standard rocket launch (Space-guns, X-30 NASP-like spaceplanes or other Sci-Fi solutions notwithstanding) you must have apogee at ~320km or higher. Otherwise your trajectory would be too shallow. Wrong. Impossible for a pure impulsive launch (e.g. space gun) but not for any real launch vehicle, which has tens of minutes of burn time, and outside the atmosphere can vector thrust arbitrarily. Whilst eccentricity and plane changes performed within the burn to orbit are expensive in terms of delta V, physics will not stop you. You can - for example - insert directly into an orbit with an apogee above your current altitude and descending, and thus never reach apogee.Wrong. As I wrote, this applies to everything behaving like a rocket. In fact, it'd be more doable with a space gun (realistically it must be either some type of EM gun or nuclear) than with a rocket: guns always have perigee below ground level, you must raise it later. And no rocket burns for tens of minutes. The longest ascent burns approaches 20m and it takes less than 1/10 of the full circle to ascent. Way too little to cut the exoatmospheric part of the flight below half circle which would be required to play games with lowering perigee without raising apogee.And yes, you can insert into an apogee of an orbit, that's not a problem at all (and rockets without upper stage restart capability did this in the past). The thing is, you can't then have the perigee not only under ground but even in the significant atmosphere (i.e. below 90km) and do a 270° around the Earth. If you wanted to go for less than half circle, then you're free to do so. But with 270° flight you're limited by the reality that perigee is necessarily 180° from the apogee. If you insert to an overhead apogee, your perigee will be at the antipode of your launch site, 180° away. Obviously, you're not doing 270° if your perigee is only 180° away and underground. It must be above the ground, and significantly at that.The way to have the lowest perigee (if this is your particular goal; it's not even Starship goal to begin with) while keeping apogee below the set level (235km here) is to have it roughly half-way between your splashdown/landing site and your launch site (give or take 5°). Apogee then must be about half way of your flight.
Quote from: sebk on 04/15/2023 01:44 pmNope. You are totally wrong.To have perigee below sea level and be able to do 3/4 of the circle around the Earth after standard rocket launch (Space-guns, X-30 NASP-like spaceplanes or other Sci-Fi solutions notwithstanding) you must have apogee at ~320km or higher. Otherwise your trajectory would be too shallow. Wrong. Impossible for a pure impulsive launch (e.g. space gun) but not for any real launch vehicle, which has tens of minutes of burn time, and outside the atmosphere can vector thrust arbitrarily. Whilst eccentricity and plane changes performed within the burn to orbit are expensive in terms of delta V, physics will not stop you. You can - for example - insert directly into an orbit with an apogee above your current altitude and descending, and thus never reach apogee.
Nope. You are totally wrong.To have perigee below sea level and be able to do 3/4 of the circle around the Earth after standard rocket launch (Space-guns, X-30 NASP-like spaceplanes or other Sci-Fi solutions notwithstanding) you must have apogee at ~320km or higher. Otherwise your trajectory would be too shallow.
Quote from: Lee Jay on 04/16/2023 09:39 pmThe Scott Manley video on this has a really interesting tidbit."...I'm going to be getting on a plane to fly out in that direction, but I'm not going there. Believe it or not there's something cooler that I have to go to. I can't tell you what it is."WTH?Perhaps the 38th Colorado Space Symposium? It runs April 17-20th. He may have already purchased admission to the event.https://www.spacesymposium.org/
Quote from: Lee Jay on 04/16/2023 09:39 pmThe Scott Manley video on this has a really interesting tidbit."...I'm going to be getting on a plane to fly out in that direction, but I'm not going there. Believe it or not there's something cooler that I have to go to. I can't tell you what it is."WTH?Clearly the Blue Origin factory tour.
Oh god NOOOO it's baaaaack, and with untrimmed quotes
Rand Simberg: Has SpaceX provided a planned trajectory?Jonathan McDowell: No, but there are enough clues in the NOTAMs, the timelines, and some FAA statements to infer one.Simberg: To what degree of precision? (And accuracy)?McDowell: perigee is between 40 and 60 km with fairly high confidence.apogee is between 200 and 245 km. inclination is 26.3 +- 0.1 deg.
No, I would say it will be "marginally orbital". For true orbital, I require perigee > 80 km.
