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Unanswered Questions

17
votes
0answers
980 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 ...
14
votes
0answers
99 views

What satellites can I receive Images from with a radio?

Are there any satellites that I can receive image data streams with an SDR and antenna? I already know about NOAA 15, 18, 19 and METEOR - M 2. Are there any other radio satellites that I can access ...
14
votes
1answer
706 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-...
12
votes
0answers
543 views

Why can't Falcon Heavy accelerate deep space payloads as fast as Atlas V and Delta Heavy?

A Falcon Heavy with an expendable core costs $95M and lifts 2.5x as much to GTO as the Atlas V. It's Pluto injection orbit payload is nearly half of the Atlas V's GTO payload. In the answer to this ...
12
votes
0answers
331 views

How often are space launches substantially delayed by protests physically at the launch site?

Update: Following a one month loss of launch capability, from Spaceflight Now, April 25, 2017; Operations resume at European-run launch base in French Guiana: Protest leaders demanded more 3 ...
11
votes
0answers
203 views

What orbital inclinations will be launched into from Scotland?

It has recently been announced that the A'Mhoine peninsula in Sutherland, Scotland will be host to the United Kingdom's first vertical launch site (assuming they can get anything done with just £30m ...
10
votes
2answers
362 views

Why do most Measurements in Space use km?

I understand the use of metric, the real question is: with how vast space truly is, why do we not use other prefixes like we do for computer memory? 1kilometer = 1,000 meters (...
10
votes
0answers
95 views

When have secondary payloads damaged the primary payload of a launcher?

Primary payload customers have traditionally been cautious when allowing secondary payloads on the same launcher. For example, a secondary payload is not trusted to have its own chemical propulsion ...
9
votes
0answers
159 views

How is Dragon-v2 prepared for being docked for months at ISS?

The Dragon spacecraft is being certified for manned spaceflight. If it's to replace Soyuz, though, it will have to serve as an escape pod for the crew. The current delivery missions are proving its ...
9
votes
0answers
132 views

Has SpaceX ever done a hot restart of a 2nd stage?

Another question highlighted this Space X 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 ...
9
votes
0answers
130 views

What happened to the Atlas IV?

I was recently reading up on the Atlas rocket family, and I noticed that for some reason the numbering went from the Atlas 3 straight to the Atlas 5. Why did they skip number 4? I am familiar enough ...
9
votes
0answers
190 views

What were some of the first two stage rockets flown?

The first US two stage rocket was bumper, a combination of a german V2 liquid fuel rocket with an US second stage. The Soviet Union had the R-1 and R-2 based on the V-2. In this list, the R-7 is the ...
9
votes
0answers
867 views

How does JAXA's “Int-Ball” manage airflow to optimally navigate inside the ISS?

above: From the BBC's Japan's zero-gravity space drone sends first pictures from ISS. This is JAXA's GEM internal ball camera, or "Int-Ball". Kawaii! It looks like it uses a three axis attitude ...
9
votes
0answers
964 views

How does the efficacy of solar cells on Mars compare with Earth?

Mars gets less than half the light that we get on Earth and there are dust storms, but the atmosphere is much thinner and there are no clouds. After all factors have been considered, how effective are ...
9
votes
0answers
185 views

Would it be possible to “ride the wave” on Venus?

Update: Newly published paper in Nature Geoscience Atmospheric mountain wave generation on Venus and its influence on the solid planet’s rotation rate has open-access links in Science News, ...

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