Quote from: AC in NC on 11/03/2017 03:18 amThe booster decides to try to hit the ASDS if things look good.Are you implying by that that they start off with the ASDS off-target and move it in if all is good?? Better go read ... [snip] ... again...
The booster decides to try to hit the ASDS if things look good.
Quote from: octavo on 11/03/2017 05:25 amQuote from: CameronD on 11/03/2017 05:00 amQuote from: AC in NC on 11/03/2017 03:18 amQuote from: CameronD on 11/02/2017 09:49 pmWe've known about the requirement to splash a stage by moving out of the way ever since the first landing attempt - so it's not only a current feature, it's a primary one - and we've all seen what can happen after a bad (non-emergency) landing.The IIP is off the Landing Target until they are committed to the attempt. The booster decides to try to hit the ASDS if things look good. The ASDS doesn't decide to try to dodge the booster if things look bad.Are you implying by that that they start off with the ASDS off-target and move it in if all is good?? Better go read https://forum.nasaspaceflight.com/index.php?topic=39766.0 and especially http://forum.nasaspaceflight.com/index.php?topic=36326.0 again..No, the barge doesn't move at all. The booster changes its landing target to the preset asds coords once it is happy that a safe landing can be attempted.Right... This is determined when the landing burn starts. If the landing engine(s) starts, it will aim for the landing point. Otherwise the consensus is that it will continue in its trajectory and crash near it. The landing burn starts pretty high so it is able to do that.
Quote from: CameronD on 11/03/2017 05:00 amQuote from: AC in NC on 11/03/2017 03:18 amQuote from: CameronD on 11/02/2017 09:49 pmWe've known about the requirement to splash a stage by moving out of the way ever since the first landing attempt - so it's not only a current feature, it's a primary one - and we've all seen what can happen after a bad (non-emergency) landing.The IIP is off the Landing Target until they are committed to the attempt. The booster decides to try to hit the ASDS if things look good. The ASDS doesn't decide to try to dodge the booster if things look bad.Are you implying by that that they start off with the ASDS off-target and move it in if all is good?? Better go read https://forum.nasaspaceflight.com/index.php?topic=39766.0 and especially http://forum.nasaspaceflight.com/index.php?topic=36326.0 again..No, the barge doesn't move at all. The booster changes its landing target to the preset asds coords once it is happy that a safe landing can be attempted.
Quote from: AC in NC on 11/03/2017 03:18 amQuote from: CameronD on 11/02/2017 09:49 pmWe've known about the requirement to splash a stage by moving out of the way ever since the first landing attempt - so it's not only a current feature, it's a primary one - and we've all seen what can happen after a bad (non-emergency) landing.The IIP is off the Landing Target until they are committed to the attempt. The booster decides to try to hit the ASDS if things look good. The ASDS doesn't decide to try to dodge the booster if things look bad.Are you implying by that that they start off with the ASDS off-target and move it in if all is good?? Better go read https://forum.nasaspaceflight.com/index.php?topic=39766.0 and especially http://forum.nasaspaceflight.com/index.php?topic=36326.0 again..
Quote from: CameronD on 11/02/2017 09:49 pmWe've known about the requirement to splash a stage by moving out of the way ever since the first landing attempt - so it's not only a current feature, it's a primary one - and we've all seen what can happen after a bad (non-emergency) landing.The IIP is off the Landing Target until they are committed to the attempt. The booster decides to try to hit the ASDS if things look good. The ASDS doesn't decide to try to dodge the booster if things look bad.
We've known about the requirement to splash a stage by moving out of the way ever since the first landing attempt - so it's not only a current feature, it's a primary one - and we've all seen what can happen after a bad (non-emergency) landing.
Except this didn't work with SES-9. My bet is that the 3-engine burn attempt didn't allow for enough time to retarget after knowing they had 3 good engines, so it was a committed attempt from the get go. When the engine(s?) failed the impact point was already on the ASDS and so poor OCISLY got Falcon-Punched at high speed.
Quote from: Lars-J on 11/03/2017 08:51 pmQuote from: octavo on 11/03/2017 05:25 amQuote from: CameronD on 11/03/2017 05:00 amQuote from: AC in NC on 11/03/2017 03:18 amQuote from: CameronD on 11/02/2017 09:49 pmWe've known about the requirement to splash a stage by moving out of the way ever since the first landing attempt - so it's not only a current feature, it's a primary one - and we've all seen what can happen after a bad (non-emergency) landing.The IIP is off the Landing Target until they are committed to the attempt. The booster decides to try to hit the ASDS if things look good. The ASDS doesn't decide to try to dodge the booster if things look bad.Are you implying by that that they start off with the ASDS off-target and move it in if all is good?? Better go read https://forum.nasaspaceflight.com/index.php?topic=39766.0 and especially http://forum.nasaspaceflight.com/index.php?topic=36326.0 again..No, the barge doesn't move at all. The booster changes its landing target to the preset asds coords once it is happy that a safe landing can be attempted.Right... This is determined when the landing burn starts. If the landing engine(s) starts, it will aim for the landing point. Otherwise the consensus is that it will continue in its trajectory and crash near it. The landing burn starts pretty high so it is able to do that.Except this didn't work with SES-9. My bet is that the 3-engine burn attempt didn't allow for enough time to retarget after knowing they had 3 good engines, so it was a committed attempt from the get go. When the engine(s?) failed the impact point was already on the ASDS and so poor OCISLY got Falcon-Punched at high speed.
Quote from: Lars-J on 11/03/2017 08:51 pmRight... This is determined when the landing burn starts. If the landing engine(s) starts, it will aim for the landing point. Otherwise the consensus is that it will continue in its trajectory and crash near it. The landing burn starts pretty high so it is able to do that.Except this didn't work with SES-9. My bet is that the 3-engine burn attempt didn't allow for enough time to retarget after knowing they had 3 good engines, so it was a committed attempt from the get go. When the engine(s?) failed the impact point was already on the ASDS and so poor OCISLY got Falcon-Punched at high speed.
Right... This is determined when the landing burn starts. If the landing engine(s) starts, it will aim for the landing point. Otherwise the consensus is that it will continue in its trajectory and crash near it. The landing burn starts pretty high so it is able to do that.
I see this event as SpaceX willing to risk damage to the ASDS to prove they can hit the target even under extreme conditions. Which would help getting approval for land landing.
Quote from: Zed_Noir on 12/23/2017 03:46 amOr SpaceX can build a fleet of BFR sized ASDS floating platforms after where ever they chose as the first BFR pad. I think a floating platform to launch and land BFR/BFS is highly unlikely. Way more issues here. For a rocket that big, a floating platform would probably need to be huge, which would be really expensive.Fixed launch pads several miles offshore seem much more likely. These would have legs that physically connect with the ocean floor, with cables and pipelines connecting back to land. This arrangement is very typical in the oil and gas industry, so it would probably be relatively economical.Quote from: Zed_Noir on 12/23/2017 03:46 amEspecially if they start the P2P (point to point) service with the BFR.For this, Elon's presentation showed a small launch platform several miles offshore. This implies a fixed launch platform that's physically connected to the ocean floor. A floating platform for a BFR size rocket would probably need to be an order of magnitude larger.
Or SpaceX can build a fleet of BFR sized ASDS floating platforms after where ever they chose as the first BFR pad.
Especially if they start the P2P (point to point) service with the BFR.
If you look closely, we see an elongated rectangular platform, which could be interpreted as a sea-going barge, ie. longer than it is wide. It clearly is sitting on legs resting on the sea bottom, but that could easily make it a jack-up vessel, as I suggested above (and I think others have before). ]
QuoteIf you look closely, we see an elongated rectangular platform, which could be interpreted as a sea-going barge, ie. longer than it is wide. It clearly is sitting on legs resting on the sea bottom, but that could easily make it a jack-up vessel, as I suggested above (and I think others have before). ]I wasn’t sure what you were seeing, but when I looked at the posted picture I get it. It’s a pretty poor frame grab. What looks like legs are actually reflections in the water. The platform is at the sea surface like a barge with no legs showing.
One thing that bothers me about launching from off shore is the impact on marine life in the area of the launch pad. All of that thrust blasting directly into shallow water is going to cook anything close by. Not good if they start finding dolphins and endangered sea turtles washing up on the beach cooked......
One thing that bothers me about launching from off shore is the impact on marine life in the area of the launch pad. All of that thrust blasting directly into shallow water is going to cook anything close by.
Quote from: Steve D on 01/03/2018 03:53 pmOne thing that bothers me about launching from off shore is the impact on marine life in the area of the launch pad. All of that thrust blasting directly into shallow water is going to cook anything close by. This is one thing you can pretty much ignore as a concern.The rocket 'only' burns ten or twenty tons of methane while clearing the tower, this is enough to only heat to boiling 1000 tons of water.Or 10m*10m*10m - around the same scale as the launchpad. It will heat a 100m*100m*10m patch on average by 1C. (this assumes that all heat is efficiently transferred to water, which it will not be, and that this is the case for the first several seconds, and no water boils)Close enough to the rocket to be thermally damaging will be extremely sonically damaging.
Quote from: speedevil on 01/03/2018 05:23 pmQuote from: Steve D on 01/03/2018 03:53 pmOne thing that bothers me about launching from off shore is the impact on marine life in the area of the launch pad. All of that thrust blasting directly into shallow water is going to cook anything close by. This is one thing you can pretty much ignore as a concern.The rocket 'only' burns ten or twenty tons of methane while clearing the tower, this is enough to only heat to boiling 1000 tons of water.Or 10m*10m*10m - around the same scale as the launchpad. It will heat a 100m*100m*10m patch on average by 1C. (this assumes that all heat is efficiently transferred to water, which it will not be, and that this is the case for the first several seconds, and no water boils)Close enough to the rocket to be thermally damaging will be extremely sonically damaging.This. It'll be the noise killing wildlife, not the heat.
Quote from: Steve D on 01/03/2018 03:53 pmOne thing that bothers me about launching from off shore is the impact on marine life in the area of the launch pad. All of that thrust blasting directly into shallow water is going to cook anything close by. Not good if they start finding dolphins and endangered sea turtles washing up on the beach cooked......Er what? They won't be directing the exhaust straight in to the water, surely?I'm not a fan of the offshore pad, at least initially anyway. Its expensive just putting in a 5 mile causeway and launch pad....
Quote from: whitelancer64 on 01/03/2018 05:53 pmQuote from: speedevil on 01/03/2018 05:23 pmQuote from: Steve D on 01/03/2018 03:53 pmOne thing that bothers me about launching from off shore is the impact on marine life in the area of the launch pad. All of that thrust blasting directly into shallow water is going to cook anything close by. This is one thing you can pretty much ignore as a concern.The rocket 'only' burns ten or twenty tons of methane while clearing the tower, this is enough to only heat to boiling 1000 tons of water.Or 10m*10m*10m - around the same scale as the launchpad. It will heat a 100m*100m*10m patch on average by 1C. (this assumes that all heat is efficiently transferred to water, which it will not be, and that this is the case for the first several seconds, and no water boils)Close enough to the rocket to be thermally damaging will be extremely sonically damaging.This. It'll be the noise killing wildlife, not the heat.Well, dead is dead. I wonder if they plan on installing blast deflectors to divert the flame off to the side instead of straight down. It may help to minimize the affect of all of the noise and heat. But if endangered sea turtles which do nest in the area get killed you can be sure that the environmentalists will shut them down. Sea life is attracted to structures such as this. I have been diving on quite a few oil rigs off the Texas coast and they all have large amounts of fish and corals growing on them.
Quote from: JamesH65 on 01/03/2018 05:13 pmQuote from: Steve D on 01/03/2018 03:53 pmOne thing that bothers me about launching from off shore is the impact on marine life in the area of the launch pad. All of that thrust blasting directly into shallow water is going to cook anything close by. Not good if they start finding dolphins and endangered sea turtles washing up on the beach cooked......Er what? They won't be directing the exhaust straight in to the water, surely?I'm not a fan of the offshore pad, at least initially anyway. Its expensive just putting in a 5 mile causeway and launch pad....I haven’t seen any mention or reason for a causeway. What’s shown is like an ASDS but larger and set up for BFR launches as well as landings. That would be MUCH cheaper and more scalable than any land based launchpad where most of limitations, cost and time would be about local impact. Seaplatforms could be built in shipyards and towed into place.
how do you get the BFS to the pad? I'd expect its going to need to come back to dry land for all the initial flights.
How do you get the fuel to the pad?
Quote from: Steve D on 01/03/2018 03:53 pmOne thing that bothers me about launching from off shore is the impact on marine life in the area of the launch pad. All of that thrust blasting directly into shallow water is going to cook anything close by. Not good if they start finding dolphins and endangered sea turtles washing up on the beach cooked......Er what? They won't be directing the exhaust straight in to the water, surely?