Op 6-2-2018 om 06:02 schreef Mike McCants via Seesat-l: > There is a press kit at: > > http://www.spacex.com/sites/spacex/files/falconheavypresskit_v1.pdf > > This gives a timeline which includes: > > 00:03:15 2nd stage engine starts > 00:08:31 2nd stage engine cutoff (SECO-1) > > and > > 00:28:22 2nd stage engine restarts > 00:28:52 2nd stage engine cutoff (SECO-2) > > I would guess that the 5 minute burn will simply get the payload > into low Earth orbit. > > Then the 30 second burn will circularlize that orbit. > > The orbit could be anything between 200 to 400 miles. Elon Musk has stated that the 6-hour coasting is to demonstrate the ability of the Falcon Heavy to directly insert into GEO. Note that Musk has also said something about a risk posed by 6 hour long coasting in the Van Allen belt. So it will not coast in LEO. So in my reading of the press kit, it would be an initial ascend into LEO (at say ~200 km altitude apogee) towards its first nodal crossing: and the burn 00:28:52 after launch would then correspond to an insertion burn into something GTO-like at the first nodal crossing, over Africa (the timing agrees to a burn at the first nodal crossing for an ~200 km initial orbit insert). So something (*very approximately only*) like this 200 * 36000 km GTO orbit: FALCON H SECO 2 option 1 1 70000U 18999A 18037.79087963 .00000000 00000-0 00000-0 0 04 2 70000 023.4400 077.4998 7311824 000.5329 359.9906 02.26675333 07 The problem with this, as Jonathan McDowell has pointed out, is that a 3rd boost into heliocentric orbit after 6 hours (half an orbit) near 01:00 UT at apogee of such a GTO-like orbit, would boost it into the inner solar system, not out towards Mars orbit. Unless they boost 180 degrees opposite to the orbital direction of movement at that moment (but that would be odd). So Jonathan's proposal of a lower ~200 x 20000 km orbit and 3rd burn around 00:50 UT into heliocentric Mars-bound orbit at perigee of this alternative orbit, after one full revolution, might be an option. Something (*very approximate only*) like this: FALCON H SECO 2 option 2 1 70001U 18999A 18037.79087963 .00000000 00000-0 00000-0 0 05 2 70001 023.4400 077.4998 6006829 000.5329 359.9829 04.10387945 01 This would also have it coast through the center of the Van Allen belt. After the 3rd boost, the resulting heliocentric orbit would then be an Apollo orbit, something *extremely approximately only* like this, based on the average of the 380-450 million km earth distance mentioned by Musk: Tp 2458156.53472 q 0.986 AU a 1.37 AU e 0.28 i 0.0-1.5 om 360.0 node 137.938 Q 1.75 AU Note: this is all conjecture and certainly not accurately enough to point a telescope at the heliocentric departure orbit. - Marco ----- Dr Marco Langbroek - SatTrackCam Leiden, the Netherlands. e-mail: sattrackcam_at_langbroek.org Cospar 4353 (Leiden): 52.15412 N, 4.49081 E (WGS84), +0 m ASL Cospar 4355 (Cronesteyn): 52.13878 N, 4.49937 E (WGS84), -2 m ASL Station (b)log: http://sattrackcam.blogspot.com Twitter: _at_Marco_Langbroek ----- _______________________________________________ Seesat-l mailing list http://mailman.satobs.org/mailman/listinfo/seesat-lReceived on Tue Feb 06 2018 - 06:37:50 UTC
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