They can't sign a contract now for something that may or may not be available or certified for launch.
Quote from: newpylong on 03/19/2015 11:57 amThey can't sign a contract now for something that may or may not be available or certified for launch. Actually, yes, they can. SpaceX/JASON-3, Atlas V/MRO & Pluto New Horizons, and OSC/OCO are perfect examples. All three were contracted before certification.
Interesting that so much propulsive energy will be needed to take the probe near the Sun, given that it will be falling into the Sun's gravity well. Was the same true for Messenger?
Wow, a Star-48 on a D-IVH--that's noteworthy in itself. Is the need for such a big LV due to the mass of the spacecraft?
Quote from: deltaV on 04/26/2014 07:55 amNASA is beginning the process of procuring a launch vehicle for solar probe plus: https://www.fbo.gov/?s=opportunity&mode=form&id=3060e9441252d36ffceae289a1fef314&tab=core&_cview=0 . The mass is 685 kg and the C3 is 154 km^2/s^2. I believe this is beyond what Falcon 9 can handle, even with a kick stage. The solicitation requires "at least one successful flight of the common launch vehicle configuration...prior to the proposal due date, which is anticipated to be September 2014," and Falcon Heavy isn't expected to launch until 2015, so it looks like SpaceX will not be eligible to bid. Presumably an Atlas will win.It wouldn't be an Atlas because such a solicitation is not needed to buy an Atlas. Atlas is already on the NLS II contract.
NASA is beginning the process of procuring a launch vehicle for solar probe plus: https://www.fbo.gov/?s=opportunity&mode=form&id=3060e9441252d36ffceae289a1fef314&tab=core&_cview=0 . The mass is 685 kg and the C3 is 154 km^2/s^2. I believe this is beyond what Falcon 9 can handle, even with a kick stage. The solicitation requires "at least one successful flight of the common launch vehicle configuration...prior to the proposal due date, which is anticipated to be September 2014," and Falcon Heavy isn't expected to launch until 2015, so it looks like SpaceX will not be eligible to bid. Presumably an Atlas will win.
I find, so I share:https://dnnpro.outer.jhuapl.edu/Portals/35/ISSFD24_Paper_Release/ISSFD24_Paper_S6-2_Guo.pdfQuoteThe launch energy is much higher than most interplanetary missions and requires a powerful three-stage launch system. The maximum launch C3 over the 20-day launch period is 154 km2/s2. The baseline launch system is an EELV (Evolved Expendable Launch Vehicle) Delta IV Heavy class launch vehicle with a standard Star 48 BV upper stage. During the Phase B development, an EELV Atlas V 551 launch vehicle was assumed. The recent switch to the more powerful Delta IV Heavy class launch vehicle will allow for more launch mass and increase spacecraft mass margin for the Phase C development.They were playing around with an enhanced Star-48 at one point (trying to keep it on Atlas).
The launch energy is much higher than most interplanetary missions and requires a powerful three-stage launch system. The maximum launch C3 over the 20-day launch period is 154 km2/s2. The baseline launch system is an EELV (Evolved Expendable Launch Vehicle) Delta IV Heavy class launch vehicle with a standard Star 48 BV upper stage. During the Phase B development, an EELV Atlas V 551 launch vehicle was assumed. The recent switch to the more powerful Delta IV Heavy class launch vehicle will allow for more launch mass and increase spacecraft mass margin for the Phase C development.
I presume, the Star-48 will be a Star-48BV version. The development of the Star-48GXV, which was to be used with Solar Probe on the originally planned Atlas-V(551), has been stopped to to high costs.
Quote from: Skyrocket on 03/19/2015 02:15 pmI presume, the Star-48 will be a Star-48BV version. The development of the Star-48GXV, which was to be used with Solar Probe on the originally planned Atlas-V(551), has been stopped to to high costs.Has there been any news or explanation as to why the Star-48GXV development became too expensive?And how expensive is too expensive?My (limited) understanding is that Star-48 motors are mature technology.
Quote from: zubenelgenubi on 03/19/2015 03:00 pmQuote from: Skyrocket on 03/19/2015 02:15 pmI presume, the Star-48 will be a Star-48BV version. The development of the Star-48GXV, which was to be used with Solar Probe on the originally planned Atlas-V(551), has been stopped to to high costs.Has there been any news or explanation as to why the Star-48GXV development became too expensive?And how expensive is too expensive?My (limited) understanding is that Star-48 motors are mature technology.Only Star-48's with fixed nozzles are mature.