You can also use that paper to calculate out in reverse the dry weight of the lander, as it posts the total delta-v available with a 20 metric ton CEV. Using those details, you reverse calculate that, to hit the 1911m/s total delta-v available with the 20.8 metric tons of fuel, of roughly 18.4 metric tons, or 39.2 metric tons fully loaded. This with MPCV would bring the total payload to 60.5 metric tons, too much for Delta IV's upper stage. *unless*You use the Centaur for both the final piece of the outgoing *and* the TLI. Having 1911 m/s, you find that it has ample delta-v for the need. ACES would further improve this, with it's better fuel fraction and fuel load.
The most recent rendering do show a tapered aft end.
Quote from: mike robel on 10/07/2011 07:17 pmThe most recent rendering do show a tapered aft end.Hey you are right! thank you. It almost looks like the taper matches the SRB skirt perfectly. It also looks like they are using the "squashed" 4/5 engine arrangement.
Did I read correctly that the current 5-Seg SRB design will only be used for the first 2 flights ? After that, ATK has a more "advanced" design, or we switch to LRBs. So that means we will have fired this design of the 5-Seg SRB more times on the ground than actually used as a booster. Who pays for the development of this new ATK design ?
Quote from: marsavian on 10/05/2011 04:04 pmThat's probably how it will pan out. Lunar and NEO can be done with Block 1A/CPS but any Mars or Martian Moon missions will take Block 2 as the reference hardware and that will be developed along with mission modules in the $3+bn budget. I suppose it's all part of ensuring the use of all the CxP hardware in development, the J-2X will be developed and then parked until the upper stage can be developed in the fixed budget.Yes.I predict the Block I will fly more than twice (maybe up to 4 times, since there are apparently about 16 RS-25Ds available, which would allow for 4 flights).So that already puts us into the 2023 - 2025 timeframe before we get Block IA. Plenty of time for political / mission focus shifts.As for the block IA, I predict we'll keep that at least until 2035.Finally, I predict that after the first two Block I flights with the current 5-segs, we will get an evaluation between different "Advanced Booster Options" (as planned), but in the end, they'll most likely stick with the ATK 5 seg boosters, for cost reasons, (unless some very effective and cheap LRBs become available or unless the 5 segs fail completely), with a vague promise of some sort of "improved booster" somewhere down the road. Just like with Shuttle, which was supposed to replace the RSRBs with something new (ASRB, 5-segs, even LRBs) several times during its lifetime...
That's probably how it will pan out. Lunar and NEO can be done with Block 1A/CPS but any Mars or Martian Moon missions will take Block 2 as the reference hardware and that will be developed along with mission modules in the $3+bn budget. I suppose it's all part of ensuring the use of all the CxP hardware in development, the J-2X will be developed and then parked until the upper stage can be developed in the fixed budget.
I predict the Block I will fly more than twice (maybe up to 4 times, since there are apparently about 16 RS-25Ds available, which would allow for 4 flights).So that already puts us into the 2023 - 2025 timeframe
Quote from: Lurker Steve on 10/05/2011 03:57 pmDid I read correctly that the current 5-Seg SRB design will only be used for the first 2 flights ? After that, ATK has a more "advanced" design, or we switch to LRBs. So that means we will have fired this design of the 5-Seg SRB more times on the ground than actually used as a booster. Who pays for the development of this new ATK design ? Yes, I noticed that too... Also note that they plan to allow the first sets of SRB's to sink the Atlantic-- not even recover for analysis... (so much for Jim's "manrated SRB's MUST be recovered and inspected for issues"). Pretty convenient way to ensure that you MUST get a fat development contract for NEW SRB's using new casings, if all the old reusable casings are in pieces on the bottom of the Atlantic... And of course with the core being DESIGNED around SRB's, LRB's will never get a fair shot... they'll be found to be "too expensive" to redesign the core and the LRB's versus the costs of SRB's, even a NEW SRB DESIGN, that utilizes the core unchanged... More thumbs on scales... SSDD... later! OL JR
As a non-rocket scientist, let me ask some questions :1) The current ATK 5-seg SRBs are designed with the same basic design of reusable casings that the Shuttle SRBs use. There is extra structural weight because the casings need to survive intact. There is a huge amount of labor to refurb the casings, but it is possible to reuse them.2) If we aren't reusing the SRBs, then some of that extra structral weight can be removed. Since the SRB become lighter by several tons, that extra weight can be translated into extra cargo the SLS could lift.3) Would these lighter SRBs have an increased thrust and/or ISP over the existing SRBs without reformulating the actual solid fuel ? 4) Without a re-formulation of the solid fuel, does this give ATK any additional advantage, other than being able to manufacture a less expensive SRB, due to the lighter structure / non-reusable design ? 5) If this comes down to purely a cost-based competition, with the vendor paying for all development of the improved booster, who wins: a pair of LRB boosters or a pair of ATK or Aerojet SRBs ?
Quote from: luke strawwalker on 10/08/2011 05:56 amQuote from: Lurker Steve on 10/05/2011 03:57 pmDid I read correctly that the current 5-Seg SRB design will only be used for the first 2 flights ? After that, ATK has a more "advanced" design, or we switch to LRBs. So that means we will have fired this design of the 5-Seg SRB more times on the ground than actually used as a booster. Who pays for the development of this new ATK design ? Yes, I noticed that too... Also note that they plan to allow the first sets of SRB's to sink the Atlantic-- not even recover for analysis... (so much for Jim's "manrated SRB's MUST be recovered and inspected for issues"). Pretty convenient way to ensure that you MUST get a fat development contract for NEW SRB's using new casings, if all the old reusable casings are in pieces on the bottom of the Atlantic... And of course with the core being DESIGNED around SRB's, LRB's will never get a fair shot... they'll be found to be "too expensive" to redesign the core and the LRB's versus the costs of SRB's, even a NEW SRB DESIGN, that utilizes the core unchanged... More thumbs on scales... SSDD... later! OL JR It may be thumbs on scales, but it can and will bite them in the butt badly. They assume, incorrectly, that they are the only SRB company in the US, ignoring that there is another, and that other has built and fired SRB's which dwarf even the 5-segment of ATK.And there is a way to build LRB's to beat SRB's even while sticking to the SRB design and load demands, in short, without redesigning the core.
Quote from: Downix on 10/08/2011 07:47 amQuote from: luke strawwalker on 10/08/2011 05:56 amQuote from: Lurker Steve on 10/05/2011 03:57 pmDid I read correctly that the current 5-Seg SRB design will only be used for the first 2 flights ? After that, ATK has a more "advanced" design, or we switch to LRBs. So that means we will have fired this design of the 5-Seg SRB more times on the ground than actually used as a booster. Who pays for the development of this new ATK design ? Yes, I noticed that too... Also note that they plan to allow the first sets of SRB's to sink the Atlantic-- not even recover for analysis... (so much for Jim's "manrated SRB's MUST be recovered and inspected for issues"). Pretty convenient way to ensure that you MUST get a fat development contract for NEW SRB's using new casings, if all the old reusable casings are in pieces on the bottom of the Atlantic... And of course with the core being DESIGNED around SRB's, LRB's will never get a fair shot... they'll be found to be "too expensive" to redesign the core and the LRB's versus the costs of SRB's, even a NEW SRB DESIGN, that utilizes the core unchanged... More thumbs on scales... SSDD... later! OL JR It may be thumbs on scales, but it can and will bite them in the butt badly. They assume, incorrectly, that they are the only SRB company in the US, ignoring that there is another, and that other has built and fired SRB's which dwarf even the 5-segment of ATK.And there is a way to build LRB's to beat SRB's even while sticking to the SRB design and load demands, in short, without redesigning the core. I am not familiar with these other SRBs. Could you please provide some information or, at least the name, as I would like to do a little reading about them? Thanks.
As a non-rocket scientist, let me ask some questions :1) The current ATK 5-seg SRBs are designed with the same basic design of reusable casings that the Shuttle SRBs use. There is extra structural weight because the casings need to survive intact. There is a huge amount of labor to refurb the casings, but it is possible to reuse them.
2) If we aren't reusing the SRBs, then some of that extra structral weight can be removed. Since the SRB become lighter by several tons, that extra weight can be translated into extra cargo the SLS could lift.
<snip>5) If this comes down to purely a cost-based competition, with the vendor paying for all development of the improved booster, who wins: a pair of LRB boosters or a pair of ATK or Aerojet SRBs ?
Quote from: Lurker Steve on 10/08/2011 04:12 pmAs a non-rocket scientist, let me ask some questions :1) The current ATK 5-seg SRBs are designed with the same basic design of reusable casings that the Shuttle SRBs use. There is extra structural weight because the casings need to survive intact. There is a huge amount of labor to refurb the casings, but it is possible to reuse them.SRB casings need to be heavy because of the large pressures the must withstand. I doubt that dropping the re-usability requirement by itself would make them much lighter.
That's not to say, however, that SRBs can't be made lighter by building them of different materials.
“Our vision is we’ll have an interface that’s generic, and we’ll be able to carry potentially different boosters and change them out as needed,” Gerstenmaier told a session of the International Astronautical Congress here Thursday. “So we could go compete in the future, maybe downsize if something’s easier for a mission that requires less thrust. We have some variability there, so if we do our job right, we’ll have the ability to change the boosters that sit on the side. That’s our ultimate goal. We’re not going to pick one.”
“It turns out that to get to the 130 metric tons, we’re going to have to redesign the five-segment booster as well,” Gerstenmaier says. “We have to go to potentially a composite case, away from our steel case to save some weight, and we might need to make a propellant change to use the more energetic propellant that sits in the solid rocket motor. So even if we go continuous solids, we’re going to have to make a pretty significant change to the solid-rocket booster segment.”
Quote from: Proponent on 10/06/2011 04:39 pmQuote from: Khadgars on 10/06/2011 05:39 amQuoteDesignating the launch vehicle requirements (for a new launch vehicle) before having the mission scope/policy/plan/blah done is bass-ackwards. ...The STS had no specific mission really until ISS and it flew for 30 years. Are not all missions designed around the launch vehicles and not the other way around (Apollo era aside)?STS had a mission: it was sold as a general-purpose space truck ...If that qualifies as a "mission", then SLS has a mission. It's being sold as a general-purpose space heavly lifter that will be large enough to handle all possible BLEO manned missions that may come up in the next 3 decades, as well as any heavy loads that would go up to LEO during that time.It's as much of a mission as STS had up front, and STS flew for 30 years.As I've warned people on the forum before, be careful with this "we can't have a rocket without a defined mission" argument. Saturn had a defined mission from it's inception, STS did not. STS had multiple purposes, but not a definate mission it was developed for. Saturn was developed for a single mission. And once that mission was achieved, it went on the scrap heap ... Since STS didn't have a singular "mission", but rather a "purpose", it continued to function in that purpose for 30 years.I'm just saying given the history of rockets with missions and rockets without, then rocket without a mission had a much longer life than the rocket with a mission...
Quote from: Khadgars on 10/06/2011 05:39 amQuoteDesignating the launch vehicle requirements (for a new launch vehicle) before having the mission scope/policy/plan/blah done is bass-ackwards. ...The STS had no specific mission really until ISS and it flew for 30 years. Are not all missions designed around the launch vehicles and not the other way around (Apollo era aside)?STS had a mission: it was sold as a general-purpose space truck ...
QuoteDesignating the launch vehicle requirements (for a new launch vehicle) before having the mission scope/policy/plan/blah done is bass-ackwards. ...The STS had no specific mission really until ISS and it flew for 30 years. Are not all missions designed around the launch vehicles and not the other way around (Apollo era aside)?
Designating the launch vehicle requirements (for a new launch vehicle) before having the mission scope/policy/plan/blah done is bass-ackwards. ...
Quote“It turns out that to get to the 130 metric tons, we’re going to have to redesign the five-segment booster as well,” Gerstenmaier says. “We have to go to potentially a composite case, away from our steel case to save some weight, and we might need to make a propellant change to use the more energetic propellant that sits in the solid rocket motor. So even if we go continuous solids, we’re going to have to make a pretty significant change to the solid-rocket booster segment.”
Quote from: Proponent on 10/06/2011 04:39 pmQuote from: Khadgars on 10/06/2011 05:39 amQuoteDesignating the launch vehicle requirements (for a new launch vehicle) before having the mission scope/policy/plan/blah done is bass-ackwards. That I pointed that out is not off-topic; your asking for mission plans for anything without SLS was off-topic."Hey guys, I'm going to go order curtains from the store, then I'll measure my windows!"EDIT:I mean, don't get me wrong, I'm glad we're finally measuring the windows, even if we ordered the curtains already.The STS had no specific mission really until ISS and it flew for 30 years. Are not all missions designed around the launch vehicles and not the other way around (Apollo era aside)? Edit: Meant STS not SLSSTS had a mission: it was sold as a general-purpose space truck that would eliminate the need for any other launch vehicles except perhaps for the very smallest. By the time of the Challenger accident it had become obvious that STS could not fulfill that role.If that qualifies as a "mission", then SLS has a mission. It's being sold as a general-purpose space heavly lifter that will be large enough to handle all possible BLEO manned missions that may come up in the next 3 decades, as well as any heavy loads that would go up to LEO during that time.
Quote from: Khadgars on 10/06/2011 05:39 amQuoteDesignating the launch vehicle requirements (for a new launch vehicle) before having the mission scope/policy/plan/blah done is bass-ackwards. That I pointed that out is not off-topic; your asking for mission plans for anything without SLS was off-topic."Hey guys, I'm going to go order curtains from the store, then I'll measure my windows!"EDIT:I mean, don't get me wrong, I'm glad we're finally measuring the windows, even if we ordered the curtains already.The STS had no specific mission really until ISS and it flew for 30 years. Are not all missions designed around the launch vehicles and not the other way around (Apollo era aside)? Edit: Meant STS not SLSSTS had a mission: it was sold as a general-purpose space truck that would eliminate the need for any other launch vehicles except perhaps for the very smallest. By the time of the Challenger accident it had become obvious that STS could not fulfill that role.
QuoteDesignating the launch vehicle requirements (for a new launch vehicle) before having the mission scope/policy/plan/blah done is bass-ackwards. That I pointed that out is not off-topic; your asking for mission plans for anything without SLS was off-topic."Hey guys, I'm going to go order curtains from the store, then I'll measure my windows!"EDIT:I mean, don't get me wrong, I'm glad we're finally measuring the windows, even if we ordered the curtains already.The STS had no specific mission really until ISS and it flew for 30 years. Are not all missions designed around the launch vehicles and not the other way around (Apollo era aside)? Edit: Meant STS not SLS
Designating the launch vehicle requirements (for a new launch vehicle) before having the mission scope/policy/plan/blah done is bass-ackwards. That I pointed that out is not off-topic; your asking for mission plans for anything without SLS was off-topic."Hey guys, I'm going to go order curtains from the store, then I'll measure my windows!"EDIT:I mean, don't get me wrong, I'm glad we're finally measuring the windows, even if we ordered the curtains already.
I'm just saying given the history of rockets with missions and rockets without, then rocket without a mission had a much long lift than the rocket with a mission...