马一龙在AMA与网友的问答

前天看直播顺便浏览了一下这个链接，发现不少有趣的东西，下面摘取一些

Q：  Falcon Heavy. Some have speculated that at stage separation the Falcon Heavy center core is too far downrange and travelling too fast to be feasibly returned to the launch site. Could you go into some detail on whether you plan to use barge landings permanently for this core, expend it depending on the mission, or take the payload loss and boost back to the launch site?
A： Yes, the Falcon Heavy center core is seriously hauling a** at stage separation. We can bring it back to the launch site, but the boost back penalty is significant. If we also have to the plane change for geo missions from Cape inclination (28.5 deg) to equatorial, then a downrange platform landing is needed.
Q：What kind of mass ratio do your upper stages have?
A：With sub-cooled propellant, I think we can get the Falcon 9 upper stage mass ratio (excluding payload) to somewhere between 25 and 30. Another way of saying that is the upper stage would be close to 97% propellant by mass.
重猎鹰为了保障GTO载荷会选择海上平台着陆而不是飞回。2级会继续提高干质比，目标是做到25至30。


Q：Has the Raptor engine changed in its target thrust since the last number we have officially heard of 1.55Mlbf SL thrust?
A：Thrust to weight is optimizing for a surprisingly low thrust level, even when accounting for the added mass of plumbing and structure for many engines. Looks like a little over 230 metric tons (~500 klbf) of thrust per engine, but we will have a lot of them :)
Q：In your recent MIT talk , you mentioned that you didn't think 2nd stage recovery was possible for the Falcon 9. This is due to low fuel efficiency of kerosene fuel, and the high velocities needed for many payloads (high orbits like Geostationary orbit). However, you also said that full reusability would be possible for the Mars Colonial Transporter launch vehicle. What have you learned from flights of Falcon 9 that taught you a. that reuse of its second stage won't be possible and b. what you'll need to do differently with MCT to reuse its second stage.
A：Actually, we could make the 2nd stage of Falcon reusable and still have significant payload on Falcon Heavy, but I think our engineering resources are better spent moving on to the Mars system. MCT will have meaningfully higher specific impulse engines: 380 vs 345 vac Isp. For those unfamiliar, in the rocket world, that is a super gigantic difference for stages of roughly equivalent mass ratio (mass full to mass empty).
猛禽所谓的系列仍然类似梅林，真空版增大面积比，但是这点现在还不能确定。推力下调到230吨，但是推质比会高的出乎意料。地面比冲348秒，真空比冲380秒。

Q：There has been a lot of speculation over comments about exactly how much mass you are hoping to send to the Martian surface with the MCT (Mars Colonial Transporter). Can you tell us how much cargo you would like to be able to land on Mars with MCT, not including the mass of the MCT itself?
N：Goal is 100 metric tons of useful payload to the surface of Mars. This obviously requires a very big spaceship and booster system.
MCT目标还是100吨火星转移轨道载荷，看来N1后继有人

Ps：
还有一堆询问教育问题的，甚至有人直接问他的个人爱好
Q：1. What is your favorite airplane? 2. What is your favorite video game? 3. What is your favorite food? 4. If you consume alcohol, what is your favorite alcoholic drink?
A：1. SR-71 Hard to pick a favorite. 2. I tend to like FPS with a story, like Bioshock, Fallout or Mass Effect, but was also a big fan of Civ and Warcraft. 3. French and BBQ. 4. Whiskey.
最喜欢的灰机是黑鸟、喜欢FPS游戏（例如质量效应，还是文明和魔兽的铁杆粉丝）、爱吃法国料理和自助烧烤，喜欢喝威士忌

Q：Follow-up question: How much do you sleep per night, on average?
A：I actually measured this with my phone! Almost exactly 6 hours on average.
大概每天睡6个小时

Q：Would you ever consider becoming a politician?
A:Unlikely.
不会选择从政

前天看直播顺便浏览了一下这个链接，发现不少有趣的东西，下面摘取一些

Q：  Falcon Heavy. Some have speculated that at stage separation the Falcon Heavy center core is too far downrange and travelling too fast to be feasibly returned to the launch site. Could you go into some detail on whether you plan to use barge landings permanently for this core, expend it depending on the mission, or take the payload loss and boost back to the launch site?
A： Yes, the Falcon Heavy center core is seriously hauling a** at stage separation. We can bring it back to the launch site, but the boost back penalty is significant. If we also have to the plane change for geo missions from Cape inclination (28.5 deg) to equatorial, then a downrange platform landing is needed.
Q：What kind of mass ratio do your upper stages have?
A：With sub-cooled propellant, I think we can get the Falcon 9 upper stage mass ratio (excluding payload) to somewhere between 25 and 30. Another way of saying that is the upper stage would be close to 97% propellant by mass.
重猎鹰为了保障GTO载荷会选择海上平台着陆而不是飞回。2级会继续提高干质比，目标是做到25至30。


Q：Has the Raptor engine changed in its target thrust since the last number we have officially heard of 1.55Mlbf SL thrust?
A：Thrust to weight is optimizing for a surprisingly low thrust level, even when accounting for the added mass of plumbing and structure for many engines. Looks like a little over 230 metric tons (~500 klbf) of thrust per engine, but we will have a lot of them :)
Q：In your recent MIT talk , you mentioned that you didn't think 2nd stage recovery was possible for the Falcon 9. This is due to low fuel efficiency of kerosene fuel, and the high velocities needed for many payloads (high orbits like Geostationary orbit). However, you also said that full reusability would be possible for the Mars Colonial Transporter launch vehicle. What have you learned from flights of Falcon 9 that taught you a. that reuse of its second stage won't be possible and b. what you'll need to do differently with MCT to reuse its second stage.
A：Actually, we could make the 2nd stage of Falcon reusable and still have significant payload on Falcon Heavy, but I think our engineering resources are better spent moving on to the Mars system. MCT will have meaningfully higher specific impulse engines: 380 vs 345 vac Isp. For those unfamiliar, in the rocket world, that is a super gigantic difference for stages of roughly equivalent mass ratio (mass full to mass empty).
猛禽所谓的系列仍然类似梅林，真空版增大面积比，但是这点现在还不能确定。推力下调到230吨，但是推质比会高的出乎意料。地面比冲348秒，真空比冲380秒。

Q：There has been a lot of speculation over comments about exactly how much mass you are hoping to send to the Martian surface with the MCT (Mars Colonial Transporter). Can you tell us how much cargo you would like to be able to land on Mars with MCT, not including the mass of the MCT itself?
N：Goal is 100 metric tons of useful payload to the surface of Mars. This obviously requires a very big spaceship and booster system.
MCT目标还是100吨火星转移轨道载荷，看来N1后继有人

Ps：
还有一堆询问教育问题的，甚至有人直接问他的个人爱好
Q：1. What is your favorite airplane? 2. What is your favorite video game? 3. What is your favorite food? 4. If you consume alcohol, what is your favorite alcoholic drink?
A：1. SR-71 Hard to pick a favorite. 2. I tend to like FPS with a story, like Bioshock, Fallout or Mass Effect, but was also a big fan of Civ and Warcraft. 3. French and BBQ. 4. Whiskey.
最喜欢的灰机是黑鸟、喜欢FPS游戏（例如质量效应，还是文明和魔兽的铁杆粉丝）、爱吃法国料理和自助烧烤，喜欢喝威士忌

Q：Follow-up question: How much do you sleep per night, on average?
A：I actually measured this with my phone! Almost exactly 6 hours on average.
大概每天睡6个小时

Q：Would you ever consider becoming a politician?
A:Unlikely.
不会选择从政