Quote from: KelvinZero on 10/02/2017 01:30 amHmmm.. I just had a whole bunch of ideas of creating an area of calm water where the docking part is.. then I realised, we must do this all the time. Eg nice quiet bays. Has anyone ever done this for floating platforms before?Cruise ships use stabilizing systems designed to minimize seasickness of passengers. Also, the deeper the below-surface draft of a ship, the more stable it can be, as I understand things. Still, none of these ships have passengers sitting within the nose of a 350 foot tall rocket atop them! - Ed Kyle
Hmmm.. I just had a whole bunch of ideas of creating an area of calm water where the docking part is.. then I realised, we must do this all the time. Eg nice quiet bays. Has anyone ever done this for floating platforms before?
Cruise ships use stabilizing systems designed to minimize seasickness of passengers. Also, the deeper the below-surface draft of a ship, the more stable it can be, as I understand things. Still, none of these ships have passengers sitting within the nose of a 350 foot tall rocket atop them!
http://dynamic-positioning.com/proceedings/dp2003/design_berkeley.pdfQuoteThe Mobile Offshore Base (MOB) is a large, self-propelled, floating, pre-positioned ocean structure formed of three to five modules and reaching up to 1,500 meters in length. It must accommodate the landing and take-off of C-17 conventional aircraft, host 3000 troops, carry 10 million gallons of fuel and provide 3 million square feet of internal configurable storage. The alignment of the modules is maintained through the use of slew-able thrusters and/or connectors. Plenty of room for passengers, methane, LOX, and commuter aircrafts to carry the passengers. A C-17 is as big as an A350 or 787. add some shopping malls, hotels, and other goodies.
The Mobile Offshore Base (MOB) is a large, self-propelled, floating, pre-positioned ocean structure formed of three to five modules and reaching up to 1,500 meters in length. It must accommodate the landing and take-off of C-17 conventional aircraft, host 3000 troops, carry 10 million gallons of fuel and provide 3 million square feet of internal configurable storage. The alignment of the modules is maintained through the use of slew-able thrusters and/or connectors.
...* doesn't the BFS suffer the same problem that the Space Shuttle suffered, which was that you are essentially launching a mini space station into orbit on every launch? Why not separate people and cargo?I know, I know, Elon's idea is that the people are the cargo, but that's barely true for commercial aviation today, in a context where ships carry everything heavy. In a context where his ride is the only ride, I have to believe there will be a huge amount more cargo than people.
Quote from: IainMcClatchie on 10/01/2017 04:01 am...* doesn't the BFS suffer the same problem that the Space Shuttle suffered, which was that you are essentially launching a mini space station into orbit on every launch? Why not separate people and cargo?I know, I know, Elon's idea is that the people are the cargo, but that's barely true for commercial aviation today, in a context where ships carry everything heavy. In a context where his ride is the only ride, I have to believe there will be a huge amount more cargo than people.Why not do both? Modern container ships have comfortable accommodations for up to 12 passengers, there are also conventional cargo freighters that have passenger accommodations. If the spaceship was taking cargo or crew to the ISS (or equivalent), lot's of room for space tourists, who get to see the ISS before heading out on their orbital excursion (or cis-lunar excursion).
Or, water depth permitting, use one or several adjacent jack-up rigs. Their legs would sit on the sea floor providing a very solid, yet still mobile if needed, platform.
if you suspend a large mass on 3 long cables 100's of meters below a floating mass it acts as a 100's m long rigid keel preventing almost all pitching and rocking. The keel cables can be wound in for ease of transport.
The current design can barely maintain it's position in rough seas. It can't get out of the way of an incoming rocket without at least a few minutes of warning, and that's assuming they can remotely retarget the ASDS (no reason they couldn't if they wanted to, just might not be a current feature).
You guys might be forgetting that, whilst it indeed needs to be a stable platform for landing, this ASDS must also be able to move quickly in an emergency - out of the way of an incoming rock(et).The current design achieves this in spades; the above suggestions possibly not so much..
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.
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.
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: biosehnsucht on 11/02/2017 09:35 pmThe current design can barely maintain it's position in rough seas. It can't get out of the way of an incoming rocket without at least a few minutes of warning, and that's assuming they can remotely retarget the ASDS (no reason they couldn't if they wanted to, just might not be a current feature).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.Truth is (a) they may have less than a few minutes warning and (b) they certainly can re-target the ASDS from the support ship - that's how they set the position now, once the tow is released.
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.