Thanks Jim, 1. I saw that FBO reference when googling the story but forgot to post the link. And via twitter AerojetRocketdyne clarified that yes, this is a 3rd stage that would fly on top of a Centaur or DCSS to provide deep space maneuvers.2. I also asked them if this was just a study result, or if this was something they were actually going to be building. Look forward to seeing the details when they come out.~Jon
Quote from: jongoff on 07/09/2014 06:23 pmThanks Jim, 1. I saw that FBO reference when googling the story but forgot to post the link. And via twitter AerojetRocketdyne clarified that yes, this is a 3rd stage that would fly on top of a Centaur or DCSS to provide deep space maneuvers.2. I also asked them if this was just a study result, or if this was something they were actually going to be building. Look forward to seeing the details when they come out.~Jon1. I believe it is for more C3 vs deep space maneuvers. Much like the STAR-48 on PNH.
2. I guess that is up to NASA and what they want to do with the study.With the demise of the Delta II, there is no more ability to provide spin stabilized STAR motors for high energy missions.
With the demise of the Delta II, there is no more ability to provide spin stabilized STAR motors for high energy missions.
I thought New Horizons used an Atlas v551 with a Star 48B on top...
1. Solar Probe Plus has apparently porked above an Atlas 551 plus a Star 48x,2. which led NASA to commission ATK to customize and tweak the Star 48 to a Star 48GXV configuration, and even that wasn't enough. I would think this upper stage contract was in the works long before the crisis with SP+, but it illustrates the need perfectly.3. As far as Solar Probe Plus goes, the article indicates they've decided to bump to either a DIVH or FH. Either pray for a large influx of cash for the DIVH, or pray the Falcon Heavy magically launches enough before the launch date to earn a NASA Category 3 certification. Seems like a NASA Science Mission Directorate nightmare, given how tightly they are squeezing their hundred millions these days.4. Also no mention about trying to reduce weight--again, no doubt they've tried everything they can think of, but it seems to me compared to the cost of upgrading to a Delta IV Heavy, some really exotic and draconian measures could still be preferred.Edit: this article says "could enable Solar Probe Plus" so I wonder if it does indeed outperform the Star 48GXV, or if they were using that phrase generically to refer to the baseline mission without the weight gain that painted them into a corner.
Quote from: a_langwich on 07/29/2014 02:29 am1. Solar Probe Plus has apparently porked above an Atlas 551 plus a Star 48x,2. which led NASA to commission ATK to customize and tweak the Star 48 to a Star 48GXV configuration, and even that wasn't enough. I would think this upper stage contract was in the works long before the crisis with SP+, but it illustrates the need perfectly.3. As far as Solar Probe Plus goes, the article indicates they've decided to bump to either a DIVH or FH. Either pray for a large influx of cash for the DIVH, or pray the Falcon Heavy magically launches enough before the launch date to earn a NASA Category 3 certification. Seems like a NASA Science Mission Directorate nightmare, given how tightly they are squeezing their hundred millions these days.4. Also no mention about trying to reduce weight--again, no doubt they've tried everything they can think of, but it seems to me compared to the cost of upgrading to a Delta IV Heavy, some really exotic and draconian measures could still be preferred.Edit: this article says "could enable Solar Probe Plus" so I wonder if it does indeed outperform the Star 48GXV, or if they were using that phrase generically to refer to the baseline mission without the weight gain that painted them into a corner.1. Has nothing to do with weight, it is the C3, which the 551 can't achieve.2. NASA did no such thing. That is ATK's own work3. RFP for launch services already went out4. See #1.
I thought APL commissioned the GXV development?
1. Has nothing to do with weight, it is the C3, which the 551 can't achieve.2. NASA did no such thing. That is ATK's own work3. RFP for launch services already went out4. See #1.
Quote from: Jim on 07/09/2014 06:31 pmWith the demise of the Delta II, there is no more ability to provide spin stabilized STAR motors for high energy missions. The study statement of work does not include the words "solid" or "liquid", so I suppose that either are options for this job. My guess would be that solids would be a strong contender, either on a spin table or with ACS 3-axis control, but the requirement for a common stage to cover a range of launch vehicles might force use of storable liquid. I suppose I should sit down with the SOW example, with its specific delta-v requirements and mass limits. The answer is probably right there in black and white. - Ed Kyle
Quote from: edkyle99 on 07/10/2014 02:56 amQuote from: Jim on 07/09/2014 06:31 pmWith the demise of the Delta II, there is no more ability to provide spin stabilized STAR motors for high energy missions. The study statement of work does not include the words "solid" or "liquid", so I suppose that either are options for this job. My guess would be that solids would be a strong contender, either on a spin table or with ACS 3-axis control, but the requirement for a common stage to cover a range of launch vehicles might force use of storable liquid. I suppose I should sit down with the SOW example, with its specific delta-v requirements and mass limits. The answer is probably right there in black and white. - Ed KyleThe "green" propellant for GPIM is the AF-315ME HAN-based liquid propellant. Though, that particular propellant can be thought of as a solid prop with water as the binder.
Do you mean it's a colloidal kind of mix? No settling or storage problems? Is the engine still pump fed? Does that affect wear on pumps? Did you mention a while back that combustion temps were a problem for some of these green propellants?