Proper engineering? Is it not proper engineering when a spacecraft temporarily modifies its pressure vessel by attaching a space station or another spacecraft to it?
Quote from: laszlo on 06/24/2012 03:57 pmProper engineering? Is it not proper engineering when a spacecraft temporarily modifies its pressure vessel by attaching a space station or another spacecraft to it?The basic vessel integrity is not changed.
LIDS is a doorway. How often do doors get thrown away after a single use?
Quote from: A_M_Swallow on 06/24/2012 11:23 pmLIDS is a doorway. How often do doors get thrown away after a single use?Every Soyuz and Progress launch?
Quote from: A_M_Swallow on 06/24/2012 11:23 pmLIDS is a doorway. How often do doors get thrown away after a single use?Most doorways don't have to be protected from hash enviroments. If dreamchaser had a cargo bay like the shuttle it would make sense to reuse, but hanging outside like that, it maybe better to discard.
Quote from: pathfinder_01 on 06/24/2012 11:57 pmQuote from: A_M_Swallow on 06/24/2012 11:23 pmLIDS is a doorway. How often do doors get thrown away after a single use?Most doorways don't have to be protected from hash enviroments. If dreamchaser had a cargo bay like the shuttle it would make sense to reuse, but hanging outside like that, it maybe better to discard.Isn't that essentially what Elon said? That it was less expensive to replace than refurbish?
Quote from: Lee Jay on 06/24/2012 11:48 pmQuote from: A_M_Swallow on 06/24/2012 11:23 pmLIDS is a doorway. How often do doors get thrown away after a single use?Every Soyuz and Progress launch?Thank you Lee Jay.How did the Shuttle connection work, did the refurbishment require extensive re-build or did USA build new connectors for every launch?
Quote from: clongton on 06/25/2012 12:02 amQuote from: pathfinder_01 on 06/24/2012 11:57 pmQuote from: A_M_Swallow on 06/24/2012 11:23 pmLIDS is a doorway. How often do doors get thrown away after a single use?Most doorways don't have to be protected from hash enviroments. If dreamchaser had a cargo bay like the shuttle it would make sense to reuse, but hanging outside like that, it maybe better to discard.Isn't that essentially what Elon said? That it was less expensive to replace than refurbish?I thought so too, but I can't find the post that quotes Elon as saying that, Is there a post or statement from Boeing on how they intend to deal with LIDS on the CST-100?
Quote from: BrightLight on 06/24/2012 11:56 pmQuote from: Lee Jay on 06/24/2012 11:48 pmQuote from: A_M_Swallow on 06/24/2012 11:23 pmLIDS is a doorway. How often do doors get thrown away after a single use?Every Soyuz and Progress launch?Thank you Lee Jay.How did the Shuttle connection work, did the refurbishment require extensive re-build or did USA build new connectors for every launch?I don't know about how much refurb got done, but I'm reasonably confident that the ODS wasn't replaced after each flight.
Quote from: BrightLight on 06/25/2012 12:06 amQuote from: clongton on 06/25/2012 12:02 amQuote from: pathfinder_01 on 06/24/2012 11:57 pmQuote from: A_M_Swallow on 06/24/2012 11:23 pmLIDS is a doorway. How often do doors get thrown away after a single use?Most doorways don't have to be protected from hash enviroments. If dreamchaser had a cargo bay like the shuttle it would make sense to reuse, but hanging outside like that, it maybe better to discard.Isn't that essentially what Elon said? That it was less expensive to replace than refurbish?I thought so too, but I can't find the post that quotes Elon as saying that, Is there a post or statement from Boeing on how they intend to deal with LIDS on the CST-100?CST-100 uses careful arrangement and a forward heat shield.
Quote from: Dappa on 06/24/2012 11:59 amQuote from: Danderman on 06/23/2012 03:11 pmAtlas 4xx has a limit of about 20,000 lbs for payload. Does the DreamChaser really have such a low weight?The DC might not actually have such a low weight. There are several factors that could benefit the (required) performance. - No payload faring, reducing weight on the Atlas.- Altlas 402 (x02?), not the 401 we are used to. Better performance to LEO because of the dual engine Centaur.- DC might do an OMS-2 or even an OMS-1 style burn, lowering the dV requirement on the Atlas.Its a structural loads issue, not a payload performance issue. Atlas 4xx actually can orbit more mass than it can lift with 2 RL-10s in the Centaur.
Quote from: Danderman on 06/23/2012 03:11 pmAtlas 4xx has a limit of about 20,000 lbs for payload. Does the DreamChaser really have such a low weight?The DC might not actually have such a low weight. There are several factors that could benefit the (required) performance. - No payload faring, reducing weight on the Atlas.- Altlas 402 (x02?), not the 401 we are used to. Better performance to LEO because of the dual engine Centaur.- DC might do an OMS-2 or even an OMS-1 style burn, lowering the dV requirement on the Atlas.
Atlas 4xx has a limit of about 20,000 lbs for payload. Does the DreamChaser really have such a low weight?
Quote from: erioladastra on 06/25/2012 01:28 amQuote from: BrightLight on 06/25/2012 12:06 amQuote from: clongton on 06/25/2012 12:02 amQuote from: pathfinder_01 on 06/24/2012 11:57 pmQuote from: A_M_Swallow on 06/24/2012 11:23 pmLIDS is a doorway. How often do doors get thrown away after a single use?Most doorways don't have to be protected from hash enviroments. If dreamchaser had a cargo bay like the shuttle it would make sense to reuse, but hanging outside like that, it maybe better to discard.Isn't that essentially what Elon said? That it was less expensive to replace than refurbish?I thought so too, but I can't find the post that quotes Elon as saying that, Is there a post or statement from Boeing on how they intend to deal with LIDS on the CST-100?CST-100 uses careful arrangement and a forward heat shield.CST-100 was baselined as APAS, with possible replacement with NDS (NASA docking system) depending on development schedules. The fwd heat shield protects the Navigation and Rendezvous sensors. CST does not plan on major refurbishment of the APAS between flights.
Quote from: dbooker on 06/23/2012 03:28 pmI read another article that said the Dream Chaser was going to have thousands of tiles. It doesn't seem like it is going to be very cost efficient totally replacing all damaged tiles, even if only scratched. Remember DC is many times smaller than Shuttle (as my visit yesterday to Udvar Hazy drove home in abundance)....
I read another article that said the Dream Chaser was going to have thousands of tiles. It doesn't seem like it is going to be very cost efficient totally replacing all damaged tiles, even if only scratched.
Quite a good point. Even with identical tiles, servicing the TPS on Dreamchaser should be at least an order of magnitude easier. And because Dream Chaser is much smaller and just getting started now, they can improve the techniques, perhaps build a better version of Dream Chaser later on (with larger tiles for less servicing? even a totally different TPS concept?) with improved turnaround capability.I don't really buy a lot of the advantages of Dream Chaser, but its reusable TPS is potentially a significant advantage.
Quote from: Robotbeat on 06/25/2012 06:08 pmQuite a good point. Even with identical tiles, servicing the TPS on Dreamchaser should be at least an order of magnitude easier. And because Dream Chaser is much smaller and just getting started now, they can improve the techniques, perhaps build a better version of Dream Chaser later on (with larger tiles for less servicing? even a totally different TPS concept?) with improved turnaround capability.I don't really buy a lot of the advantages of Dream Chaser, but its reusable TPS is potentially a significant advantage.I was under the impression that Dreamchaser used a heat shield "shoe" that uses an ablative substance:
I was under the impression that it largely used reusable tiles. Certainly the hottest parts (if not ablative) would be RCC pieces (really expensive, but can be in single large pieces and should be reusable...).I must admit the impression was formed quite a while ago and things may have changed.