AFAIK there are no stats for damage to satellites on the Shuttle. It never happened.
Quote from: Space OurSoul on 12/17/2015 08:18 pmIt is designed to cruise (at Mach 3) on bypass ram engines alone, enabling intact abort to a wide range of destinations late in the launch phase even with both sets of rockets out of action.Well I have been interested in Skylon for a long time and never come across that gem of info before. That's quite something. With all main engines out it can still propel itself with the bypass ramjets? Is this a fact?
It is designed to cruise (at Mach 3) on bypass ram engines alone, enabling intact abort to a wide range of destinations late in the launch phase even with both sets of rockets out of action.
Uh, how far would it hobble Skylon operators to ban traditional toxic hypergols in payloads? Considering all the moves to electric thrusters as it is, what specific scenarios end up essentially needing hypergolic propellants? The missions that come to mind is any kind of short, high thrust scenario where a solid kick stage is undesirable, so some manned systems perhaps?
Well I have been interested in Skylon for a long time and never come across that gem of info before. That's quite something. With all main engines out it can still propel itself with the bypass ramjets? Is this a fact?
Quote from: john smith 19 on 12/18/2015 09:24 amAFAIK there are no stats for damage to satellites on the Shuttle. It never happened. No stats are required for shuttle. The payloads were just required to survive an abort landing. The capability to be operable after an abort landing is s different story.
1. IIRC the 4 satellites of the Cluster mission that flew on the first Ariane 5 were re flown after recovery from the Guyianan jungle.2. I would expect most Skylon failure modes to be more benign (in terms of acceleration and heating) than a 1st stage engine explosion and subsequent ELV RUD.
I don't think so. Do you have a source for that claim ? I think they were completely destroyed and new spacecrafts had to be build.
Quote from: Asteroza on 12/16/2015 03:46 amUh, how far would it hobble Skylon operators to ban traditional toxic hypergols in payloads? Considering all the moves to electric thrusters as it is, what specific scenarios end up essentially needing hypergolic propellants? The missions that come to mind is any kind of short, high thrust scenario where a solid kick stage is undesirable, so some manned systems perhaps?There isn't "all the moves", it has only been GEO comsats that have done it. The issue is for attitude control and not orbit changing. Most spacecraft need thrusters with more power than electric ones.
They compute only a one-off count, not a recylce of the acquisition each 10 launches. Basically, it is like buying one skylon and using it 200 times, or buying a falcon 9 and using it 200 times. which is wrong.
Quote from: francesco nicoli on 12/16/2015 03:05 pmThey compute only a one-off count, not a recylce of the acquisition each 10 launches. Basically, it is like buying one skylon and using it 200 times, or buying a falcon 9 and using it 200 times. which is wrong. Where does the assumption that a F9 first stage will only have a life of 10 flights come from? Is this a SpaceX number?
Quote from: Vultur on 12/24/2015 06:15 pmQuote from: francesco nicoli on 12/16/2015 03:05 pmThey compute only a one-off count, not a recylce of the acquisition each 10 launches. Basically, it is like buying one skylon and using it 200 times, or buying a falcon 9 and using it 200 times. which is wrong. Where does the assumption that a F9 first stage will only have a life of 10 flights come from? Is this a SpaceX number?Indeed, last I heard Elon Musk was optimistic that a booster could be launched 20 times before major refurbishment would be necessary (like taking the stage apart and cleaning and checking every piece of it). I do not remember anything about 10 being the limit (even with refurbishment).
Quote from: Elmar Moelzer on 12/24/2015 10:57 pmIndeed, last I heard Elon Musk was optimistic that a booster could be launched 20 times before major refurbishment would be necessary (like taking the stage apart and cleaning and checking every piece of it). I do not remember anything about 10 being the limit (even with refurbishment).Probably his usual excessive optimism.
Indeed, last I heard Elon Musk was optimistic that a booster could be launched 20 times before major refurbishment would be necessary (like taking the stage apart and cleaning and checking every piece of it). I do not remember anything about 10 being the limit (even with refurbishment).
Quote from: Archibald on 12/24/2015 09:47 amI don't think so. Do you have a source for that claim ? I think they were completely destroyed and new spacecrafts had to be build. Yes new spacecraft were built; IIRC at least one was made using spare parts from the first mission which is perhaps the source of confusion.
Yeah. You'd have to talk spacecraft manufacturers into using less toxic propellants like hydrogen peroxide/something, hydrogen peroxide and the new "green" monoprops instead of hydrazine family/N2O4 and hydrazine.
Probably there is no hard limit to what could be done.
Well, so far he has done everything he claimed he would do... taking a bit longer than anticipated but he did it.
Also I am sure that this estimate is based on their experiences gained during their engine test program and the grasshopper tests. So if he is not the one who is in the position to make a prediction about this, who is?
Upper stage reuse of the F9 (and FH) has also been abandoned.
True, but the question of Skylon's ability to attract enough investment to be built, and profitability if it is built and works, is strongly affected by what other reusable launch vehicles/systems are around.