All Questions
11
questions
21
votes
2
answers
23k
views
Why will Starlink satellites use krypton instead of xenon for electric propulsion?
The press kit for the first Falcon 9 Starlink launch and deployment of the first 60 satllites scheduled for May 15, 2019 says:
With a flat-panel design featuring multiple high-throughput antennas ...
- 149k
38
votes
6
answers
9k
views
Why did it take so long for methane to be used as a rocket propellant?
SpaceX have put methane on the map as a rocket fuel, but they weren't the first to consider its use. The first experiments in building a rocket engine that uses methane date back to 2007.
Now methane ...
- 128k
11
votes
1
answer
16k
views
How much fuel does the Falcon Heavy use? What is the price RP-1?
Does anyone know how much fuel the Falcon Heavy can hold, the RP-1 fuel and liquid oxygen as oxidizer, and how much of that will it use to get to a certain point?
I don't know how i would calculate ...
- 175
5
votes
1
answer
418
views
Why did the "Secretive SpaceX Zuma Launch" make a big "S" or yin-yang shape in the sky?
The Space.com article Strange Sky Spiral May Come from Secretive SpaceX Zuma Launch shows images from this Tweet and this tweet, the second of which was posted by Dr Marco Langbroek (@Marco_Langbroek):...
- 149k
15
votes
3
answers
6k
views
Is the supercooled LOX used in Falcon 9 Full Thrust a first?
One of the changes made to the Falcon 9 v1.1 Full Thrust was using supercooled liquid oxygen at 66 K (-340 F) as well as chilled RP-1.
I've seen various claims that this is a first in the industry. ...
- 773
4
votes
1
answer
4k
views
What is the spherical tank in this drawing of the BFS?
The big news in this article is the extremely large carbon-fiber fuel tank. However, the drawing in the article does not show it well. Instead what stands out like a sore thumb in the drawing is the ...
- 149k
8
votes
1
answer
754
views
SpaceX Falcon 9 Reusable first stage propellant for return
How much propellant is required to return the Falcon 9 Reusable's first stage after separation?
- 10.1k
4
votes
2
answers
552
views
How could a hydrazine and N2O4 cloud (or it's reactants) show up in weather radar?
Question: How could a hydrazine and N2O4 cloud (or it's reactants) show up in weather radar?
Tweet:
This is what an ‘anomaly’ looks like on weather radar.
Tweet (with GIF):
Dragon's static fire ...
- 149k
4
votes
0
answers
99
views
What is the icy formation on these rockets? [duplicate]
I've sometimes seen icy formations form and break off of spacecraft. In today's SpaceX launch, there are a couple examples (times based on video) at 51:55 where you can see it growing:
Two similar ...
- 1,144
4
votes
2
answers
9k
views
Calculate Falcon 9 CO2 emissions
Falcon 9 uses Merlin 1 Kerosene based engines. Are there 4 Merlin 1 engines? This seems simple to calculate:
Number of Merlin Engines x Merlin 1 fuel capacity(gallons) x Kerosene to CO2 Production.
...
- 43
3
votes
0
answers
201
views
Does Starship run on Slushies?
Cryogenic slush (a mixture of liquid and solid) can potentially store propellants at higher density than cryogenic liquid. For instance, hydrogen slush is 16-20% denser than liquid hydrogen. https://...
- 22.9k