Quote from: yg1968 on 08/13/2014 06:56 pmOn a more positive note (from the same article), it looks like ESA has resolved the SM's excess weight issue:QuoteESA’s assurances followed a May 19 preliminary design review where Airbus officials showed they had resolved the module’s excess weight.I thought the main issue was with the command module weight and its parachutes. How much overweight was the SM?
On a more positive note (from the same article), it looks like ESA has resolved the SM's excess weight issue:QuoteESA’s assurances followed a May 19 preliminary design review where Airbus officials showed they had resolved the module’s excess weight.
ESA’s assurances followed a May 19 preliminary design review where Airbus officials showed they had resolved the module’s excess weight.
Umm... Didn't Apollo use the same strategy? Actually using the same engine, too?
Quote from: simpl simon on 05/26/2014 08:57 pmNo.The large engine nozzle in the centre (ex-Shuttle OMS engine) is for ascent abort situations. The smaller engines around the perimeter are for in-space delta-V manoeuvres (e.g. lunar orbit insertion, trans-Earth injection).And anyway, ESA's lunar lander has been cancelled.The OMS Engine? For Ascent Abort? Holy cats, anybody thought about what that's going to do to the oxidixer tank right beneith that thing? I guess they want to save a bit of money on the self destruct of teh stack if they have to do an ascent abort. Use the OMS engine to start a chain reaction explosion as it tries to get away from the rocket! Did they at LEAST put a flame deflector on top of the tank to avoid the inevitable BOOM?
No.The large engine nozzle in the centre (ex-Shuttle OMS engine) is for ascent abort situations. The smaller engines around the perimeter are for in-space delta-V manoeuvres (e.g. lunar orbit insertion, trans-Earth injection).And anyway, ESA's lunar lander has been cancelled.
Quote from: pippin on 08/13/2014 07:41 pmUmm... Didn't Apollo use the same strategy? Actually using the same engine, too?It did, but consider - the SLA panels created a decent amount of physical separation between the upper dome of the propellant tanks, even disregarding the presence or absence of an LM underneath. Of course, that being said, I can't imagine that the effect of the SPS firing off into an LM ascent stage loaded with hypergolic propellants would be too gentle.But either way, it beats the alternative of remaining attached to an off-trajectory booster or one that is in the process of rapid, unplanned disassembly ...
Might not the sudden, violent depressurisation of the tank wouldn't result it high-speed debris striking Orion?
Quote from: Proponent on 08/16/2014 04:26 amMight not the sudden, violent depressurisation of the tank wouldn't result it high-speed debris striking Orion?Depressurization of the dome of the stage below?Well first, the tank is at or near depletion, so whatever is left is low pressurant gas.
Quote from: robertross on 08/16/2014 04:27 pmQuote from: Proponent on 08/16/2014 04:26 amMight not the sudden, violent depressurisation of the tank wouldn't result it high-speed debris striking Orion?Depressurization of the dome of the stage below?Well first, the tank is at or near depletion, so whatever is left is low pressurant gas. How...? In most late ascent abort scenarios after LAS jettison, the upper stage will be completely FULL - where the SLS core has not been staged yet.
Or is it the plan to drag the Orion LAS almost all the way to orbit?
How...? In most late ascent abort scenarios after LAS jettison, the upper stage will be completely FULL - where the SLS core has not been staged yet.
I'm not suggesting that the people involved don't know what they are doing - I was merely pointing out that there will be a significant portion of the ascent between 1) LAS ejection and 2) SLS core stage burnout. In that time period, the SM abort engine would indeed be firing on top off a fully loaded iCPS(?) stage.
Multi-Purpose Crew Vehicle European Service Module(MPCV-ESM)Recovery measures were implemented to get back ontrack for FM1 shipment date of March 2017. The massnon-compliance has been improved, and the remainingover mass is considered manageable. Savings have beenidentified with a new concept of a bellow water tank.Deletion of a Command (and) Monitoring Unit shouldallow a further saving. Clarification on Thermal ControlSystem mass increase and assessment of an alternativeradiator layout is under way. The MPCV mission data forthe ESM design and verification were baselined. The CrewModule Adapter SM mechanical interface design wasagreed. The MPCV PDR is scheduled for 15 May with allintermediate milestones achieved.
Wont be a big deal, look at the 2:30 mark of this video showing a Titan II upper stage firing right at the first stage, it collapses but doesnt explode
The old Constellation plan had the Orion LAS jettisoned shortly after first and second stage separation. I'm assuming the same concept will apply to SLS. It's probably not needed in case of a problem with the second stage.
Quote from: RonM on 08/16/2014 08:20 pmThe old Constellation plan had the Orion LAS jettisoned shortly after first and second stage separation. I'm assuming the same concept will apply to SLS. It's probably not needed in case of a problem with the second stage.The LAS is ejected at T+330s, during the core stage burn. FromS. Creech, J. Holladay and D. Jones, "SLS dual use upper stage (DUUS) opportunities," NASA, Apr. 2013.http://ntrs.nasa.gov/search.jsp?R=20130013953