Unanswered Questions
1,155 questions with no upvoted or accepted answers
21
votes
0answers
1k views
Where is the TEA-TEB stored for the Merlin engines onboard Falcon 9?
The Merlin 1D engines can restart up to four times, they use the pyrophoric mixture of TEA-TEB (Triethylaluminum-Triethylborane) to ignite the engines. My question is where is this stored in the ...
15
votes
0answers
315 views
Has SpaceX ever done a hot restart of a 2nd stage?
Another question highlighted this SpaceX commentary for the GRACE-FO launch:
Now in order to fly an efficient trajectory for both of the payloads, we’re actually now running the second stage engine ...
14
votes
1answer
863 views
What is the value of the cross-track angle between the two designated CRS-4 first stage recovery zones?
For the SpaceX Falcon 9 launch on its Dragon/CRS-4 cargo delivery mission to the International Space Station, according to Spaceflight 101, two downrange safety zones have been identified:
The SpX-...
13
votes
0answers
280 views
How did “the kid” (John Meisenheimer) calculate that there was a wave in the jet stream and Explorer 1 would be okay to launch?
The tough but timely question NASA at sIxty years, will there be a new moonshot mandate? links to the NASA YouTube video NASA 60th: How It All Began which shows a lot of really nice, historical file ...
12
votes
0answers
217 views
Does the FAA still license the people who fold human-rated reentry parachutes?
One of the links in the question International Orange? is the History.com article The Amazing Handmade Tech That Powered Apollo 11’s Moon Voyage which says of Apollo capsule re-entry and landing ...
11
votes
0answers
100 views
Launch to orbit delta-v penalty from Venus compared to Earth?
Thinking about the no atmosphere caveat here made me think of Venus, which is the opposite of no atmosphere for solid/rocky bodies in our solar system.
Earth's low orbital velocity is about 7.8 km/s. ...
11
votes
0answers
135 views
At what surface gravity can't astronauts do full steps anymore?
We know that on the Moon in ~1/6 g the Apollo astronauts couldn't make full steps because they jumped with each step. At what surface gravity could you walk more like on Earth and at what gravity ...
11
votes
1answer
450 views
Documented economics of STS Solid Rocket Booster reuse?
I often see the claim that the Shuttle SRBs cost as much to recover & refurb as it would to build a new one. I've probably even parroted this claim myself.
But, are there any actual studies or ...
11
votes
0answers
578 views
How strong is the electric charge capacity of Martian dust storms?
In my answer to What would it feel like to be in a Martian dust storm? I assert that Martian dust storms would be best avoided, and as one of the reasons (besides carrying corrosive chemicals like ...
11
votes
0answers
150 views
How does increased environmental radiation affect medication potency, long and short term?
The issue of the effects of radiation on medication potency is not only important for long term stays in the ISS, but also very important for longer duration journeys and even for colonization.
One ...
10
votes
0answers
168 views
Are there any possible methods for keeping surface water on mars?
I've been reading this wikipedia article on terraforming mars. One of the major issues with terraforming mars is essential molecules and elements escaping the planet. There have been several ...
10
votes
0answers
711 views
Why NASA's sudden renewed (apparently) interest in Wax hybrid engines? Which property is so attractive now?
update:
This answer links to Larry Russel Kellogg which links to NASA Tests Environmentally Friendly Rocket Fuel where images of Test firing of new Paraffin-Based Fuel at NASA Ames Research Center 1/...
9
votes
0answers
100 views
Have there ever been any incidents where something valuable was unintentionally throw out with the trash?
In "What do astronauts do with their trash on the ISS?", a commentor asked the title question and was encouraged to make it a new question, but apparently never did.
The linked question is referring ...
9
votes
0answers
94 views
What is the current location of Link-built Apollo Mission Simulators?
There seems to be confusion about the final disposition of, and even the number of, Apollo Mission Simulators built by Link Flight Simulation Division. This question is not about any simulator built ...
9
votes
0answers
96 views
Detailed information about the Soyuz descent module connection box?
Anyone have some detailed information about how all this connectors, located in the soyuz descent module?
Are they used only when they setup the Soyuz or they are ...
