Quote from: Proponent on 09/29/2017 11:15 amQuote from: TrevorMonty on 09/28/2017 06:36 pmThe only way to match SLS BLEO capabilities with smaller LV is by distributed launch, which is whole new technology to be developed and proven. Even then the EELVs in 2010 would've been to small, something in 35-50t class would be need. Commercially developed DL and 3 vehicles in this class are now in development, only 5-7yrs to late.This is the same fallacy in another form: you identify one weakness of a non-heavy-lift approach and conclude that heavy lift is better. The fact remains that there is as yet literally no technical justification for SLS.The same can be said to your argument "The fact remains that there is as yet literally no technical justification for SLS". Technical justification? That is as subjective a "fact" as any.
Quote from: TrevorMonty on 09/28/2017 06:36 pmThe only way to match SLS BLEO capabilities with smaller LV is by distributed launch, which is whole new technology to be developed and proven. Even then the EELVs in 2010 would've been to small, something in 35-50t class would be need. Commercially developed DL and 3 vehicles in this class are now in development, only 5-7yrs to late.This is the same fallacy in another form: you identify one weakness of a non-heavy-lift approach and conclude that heavy lift is better. The fact remains that there is as yet literally no technical justification for SLS.
The only way to match SLS BLEO capabilities with smaller LV is by distributed launch, which is whole new technology to be developed and proven. Even then the EELVs in 2010 would've been to small, something in 35-50t class would be need. Commercially developed DL and 3 vehicles in this class are now in development, only 5-7yrs to late.
Quote from: edkyle99 on 09/26/2017 03:49 amQuote from: ZachF on 09/25/2017 11:14 pmhttps://forum.nasaspaceflight.com/index.php?topic=43641.0The entire global LV business is $5.5 billion/year... That we're spending $4 billion/year just to develop SLS/Orion is a titanic waste of money.Even $1.5-2 billion a year is equal to 1/4 to 1/3 of the global LV business by $, for about one launch per year.The SLS/Orion budget would be for SLS *and* Orion - launch plus payload, so obviously launch would not cost $1.5-2 billion per year. It would cost half as much or less, for the equivalent mass capability of roughly 6-8 big expendable launch vehicles or 12-14 medium size launchers. Since 2007 inclusive, only ten launches out of the 853 total launches worldwide have gone beyond Earth orbit. Those payloads weighed a combined 20.3 tonnes. SLS 1B could do half-again as much mass beyond Earth orbit in one launch, and probably for less money than those 10 launches. - Ed KyleCould do, but will not do as no such payload exists and will not exist given the path NASA has chosen for developing a deep space outpost.
Quote from: ZachF on 09/25/2017 11:14 pmhttps://forum.nasaspaceflight.com/index.php?topic=43641.0The entire global LV business is $5.5 billion/year... That we're spending $4 billion/year just to develop SLS/Orion is a titanic waste of money.Even $1.5-2 billion a year is equal to 1/4 to 1/3 of the global LV business by $, for about one launch per year.The SLS/Orion budget would be for SLS *and* Orion - launch plus payload, so obviously launch would not cost $1.5-2 billion per year. It would cost half as much or less, for the equivalent mass capability of roughly 6-8 big expendable launch vehicles or 12-14 medium size launchers. Since 2007 inclusive, only ten launches out of the 853 total launches worldwide have gone beyond Earth orbit. Those payloads weighed a combined 20.3 tonnes. SLS 1B could do half-again as much mass beyond Earth orbit in one launch, and probably for less money than those 10 launches. - Ed Kyle
https://forum.nasaspaceflight.com/index.php?topic=43641.0The entire global LV business is $5.5 billion/year... That we're spending $4 billion/year just to develop SLS/Orion is a titanic waste of money.Even $1.5-2 billion a year is equal to 1/4 to 1/3 of the global LV business by $, for about one launch per year.
SLS is a bit of an Ouroboros....
To support lunar operations the DSG does not need an airlock, just two docking ports.
NASA needs to duck political meddling, possibly by getting extra features included in additional modules.
If there is significant messing around with the habitation modules requirements NASA can simply buy and fit a B330 from Bigelow as a 'temporary' measure.
The ACES lander does not have a heat shield so it cannot reenter. To be reusable therefore the lander needs leaving in either lunar orbit or LEO.
and at the present time there is no where in space they can be refuelled
A second ACES transfer stage that pushes a capsule, able to reenter, to DSG permits manned Moon landings.
Quote from: A_M_Swallow on 09/30/2017 03:25 am{snip}and at the present time there is no where in space they can be refuelledFor reasons of flight safety, I don't see that place being the DSG. NASA is not going to attach large tanks of pressurized, temperature-sensitive propellants to a man-tended station like DSG.And there probably won't be a place (or places) for refueling in space some time to come. Until there is sufficient demand, it doesn't make sense to invest in a propellant depots. One-off upper stages or maybe robotic servicers will do the work until then.
{snip}and at the present time there is no where in space they can be refuelled
QuoteA second ACES transfer stage that pushes a capsule, able to reenter, to DSG permits manned Moon landings.Now we're back to the airlock, which doesn't come online until 2026 or later.
Back in 2010 the concept of doing an RTLS of a an orbital-class rocket booster also seemed to be an impossible concept. And yes, it was suggested by that same eccentric billionaire (with the difference that Elon wasn't a billionaire back then).
Per waiting on the new EM-1 date.L2 info shows they are deciding between the "best case" date of December 2019 and a "risk informed" date of Q2 (around May) 2020 for EM-1.
Quote from: Chris Bergin on 10/14/2017 01:55 pmPer waiting on the new EM-1 date.L2 info shows they are deciding between the "best case" date of December 2019 and a "risk informed" date of Q2 (around May) 2020 for EM-1.This is getting way beyond ridiculous. We are talking a 3 year delay from the originally NASA-targeted launch date and almost 4 years of delay from the mandated-by-law launch date.What the h*ll is the delay this time? It can't be all ESM related.
If NASA really is scheduling a possible EM-1 date of May 2020, the hard minimum 30 month duration for pad rework prior to EM-2 would put EM-2 at NET Oct 2022.
I'm still curious about Europa Clipper's launch between EM-1 and EM-2. How vulnerable will it be if either of the Orion launches are delayed? It still seems to be poised to play guinea pig for the EUS before the crew ride it themselves.
Quote from: woods170 on 10/14/2017 07:07 pmQuote from: Chris Bergin on 10/14/2017 01:55 pmPer waiting on the new EM-1 date.L2 info shows they are deciding between the "best case" date of December 2019 and a "risk informed" date of Q2 (around May) 2020 for EM-1.This is getting way beyond ridiculous. We are talking a 3 year delay from the originally NASA-targeted launch date and almost 4 years of delay from the mandated-by-law launch date.What the h*ll is the delay this time? It can't be all ESM related.Actually, most of it is. The ESM delivery date keeps sliding. Some of the delays were related to the friction stir weld issues (ie, core stage) and some were driven by software, but by and large the more recent slips are driven by ESM delivery.
There's always a blame game. The Orion end of the stack blamed Ares I during the CxP schedule stretch and it turned out it was mainly their end. I think we all remember the flapping over Thurst Oscillation, which was overplayed. Orion's continual changes were feeding down to Ares I, not the other way around. Orion said they had to keep changing because Ares I couldn't lift it. Back and forth. Probably needed better project management. ESM certainly gets a lot of the blame. I think a lot of that is valid when they have to send an ESM minus some of its tanks just to protect some schedule.
In September, the agency said in a statement that it would announce a new target date for EM-1 in October, citing the need to account for a range of issues, including progress on the European-built Orion service module and shutdowns at NASA centers from hurricanes in August and September.However, an update in October is increasingly unlikely. “Within a few weeks, I think [NASA Acting Administrator Robert Lightfoot] intends to codify whatever that date is going to be,” Todd May, director of NASA’s Marshall Space Flight Center, said in remarks at the American Astronautical Society’s Wernher von Braun Memorial Symposium here Oct. 25.Bill Hill, deputy associate administrator for exploration systems development at NASA, offered a similar assessment. “Probably in the next month, maybe sooner,” he said in an interview.
The management problems abound for the SLS/Orion/GSE projects.https://spacepolicyonline.com/news/gao-warns-nasa-to-avoid-management-mistakes-like-those-that-led-to-columbia-tragedy/My primary worry about the NASA upper management is that they seem to be cut off from what is really happening at the lower levels and are in the dark about schedule and possibly even costs (since schedule and costs are two peas in the same pod) but hopefully not about safety. But this latest GAO report gives questions even about that aspect.Some of that is having less control and insight into the actual activities than they normally would have over the contractors because of the changes in the contracts to help supposedly reduce costs. It was a risk. One that seems to have bitten them. But this is not to say that even if they had the improved control and insight that the end result would be any different. There is evidence including the nature of the problems that have plagued the program that no other action other than what was taken would have resulted in any better schedule outcome. But going forward in a more tightly interdependent task schedule this loser coupling may pose schedule risks that can cause it's own problems. Too many players, contractors, NASA centers, even independent NASA project managers that just coordinate their activities and are not really controlled except at the NASA Director's level. The main problem is 3 separate congressional budget lines which makes 3 separate independent project mangers that manage their separate projects independently and only abide by the interface control documentation existing between them.