# All Questions

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### Was Arthur J. Schwaniger one of very few US born NASA scientists using metric units?

Free-return trajectories were studied by Arthur Schwaniger of NASA in 1963 with reference to the Earth–Moon system. Those trajectories were used for the first Apollo missions. Mr. Schwaniger, who ...
2k views

### What is this spacecraft tethered to another spacecraft in LEO (vintage)

In the really nice video Brian Eno on Apollo at 03:40 there is (possibly Apollo-era but not necessarily Apollo) footage of a spacecraft tethered to another ...
206 views

### What does this humanoid silhouette on SpaceX's Starhopper represent?

The images below are from a NASA Spaceflight forum post and can be seen in @bolsachicagal's twitter and also in this NASASpaceFlight tweet. Question: What does this silhouette of a bipedal individual ...
424 views

### How “hard” did Apollo 12 turn left just before it landed?

This answer to How much were the LMs maneuvered to their landing points? includes Figure 34 from Floyd Bennett's 1972 Apollo Experience Report - Mission Planning for Lunar Descent and Ascent; NASA TN ...
34 views

### Mass/weight information about stage separation mechanism

How can I get mass/weight information about rocket stage separation mechanisms that are used in multi-stage rockets? I plan to create an excel table to compare stage separation mechanisms by weight ...
119 views

### Why did a phase mismatch between the Apollo 11 LM's RR and AGC generate a large numbers of interrupts?

A critical aspect of the cause of the famous 1202 and 1201 alarms reported by the Apollo Guidance Computer (AGC) during the decent of the Apollo 11 LM is that the rendezvous radar (RR) was using a "...
519 views

### How much were the LMs maneuvered to their landing points?

The story of the Apollo 11 landing includes Armstrong having to fly the LM beyond a boulder field at the automatically targeted site. Was this essentially continuing along the same track the LM had ...
255 views

### Why did Germany launch its spy satellites from Russia?

I just saw this article on a family of German recon sats https://en.wikipedia.org/wiki/SAR-Lupe They were all launched from Russia! Why? Why not an Ariane launch from French Guiana? I can ...
114 views

### Why do we not have ten small rovers on the Moon already? [closed]

We already did the develop and testing of Opportunity and Curiosity for 15 years. Why not crank out ten more, and put them on a Falcon heavy for the Moon's south pole?
91 views

### ESA's contribution to ISS: what has succeeded the ATV?

ESA's ATV cargo spacecraft was built and flown as part of ESA's contribution to the ISS operating cost. This program has ended. What has replaced it? Has ESA's financial contribution increased, or ...
86 views

### What exactly is a “Next Generation Lunar Reflector”? Difference in design and performance?

Space.com's 50 Years After Apollo, India Is Carrying a NASA Laser Reflector to the Moon (And It's Only the Start) is a little confusing because it talks about three retroreflectors: - Apollo era ...
51 views

### How can I calculate if a satellite is currently in sunlight or eclipse using pyEphem or Skyfield (preferred)?

I'd like to add this to some existing python scripts to model cubesat battery life and payload temperature but the math escapes me.
115 views

### How long will traces of the moon landings survive?

Inspired by this question: How long will traces of the moon landings (e.g. footsteps, the hardware) or other human activity on the moon approximately survive to be recognized as unambiguous evidence ...
71 views

### Impact of having two antennas on link budget calculations

I'm working on link budget of a cubesat mission that needs to have two dipole antennas that are perpendicular to each other. I want to know if having two antennas affect the link budget? losses, and ...
128 views

### What causes this diamond to appear from a single Raptor engine firing?

As seen on this video posted by Elon Musk https://twitter.com/elonmusk/status/1154629726914220032?s=19
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### Could Spacex build a starhopper (starship prototype) at Vandenburg, CA launch site?

I know Spacex is building a starhopper (starship prototype) in Texas and Florida. Could they also build a starhopper prototype at the Vandenburg, CA launch complex? I know Vandenburg is better for ...
142 views

### Does central Merlin have a different specific impulse?

On a Falcon 9 booster, does the central engine experience unique variations of its ISP due to its plume bordering the eight other plumes? If there is any influence, how does the ambient relative ...
25 views

### Orbital period from TLE data [duplicate]

Is there a way to calculate the orbital period from the Two Line Element (TLE) data?
2k views

### How were the LM astronauts supported during the moon landing and ascent? What were the max G's on them during these phases?

I understand that the LM astronauts descent trajectory had them flying feet first in a standing position during the descent to the lunar surface and again on ascent. But it seems there must have been ...
7k views

### Why did Saturn V not head straight to the moon?

This may seem a naive question, but as I understand it one of the reasons for the enormous energy expended by rockets is the extremely high speed (around 28,000kph) you need to reach to achieve a ...
74 views

### What is the process to verify the orbit of a satellite in a list of artificial earth satellites?

From the answers to What is the name of the 'register' that keeps track of all the satellites? we can see that there are more than three 'registers' of artificial satellites - starting with: The ...
552 views

### Does static fire reduce reliability?

I do understand that static fire helps discovering malfunctions, as explained in this answer. A launch exerts an important stress on rockets' engines (high temperature and pressure, vibrations,...) ...
373 views

### Why did they bother closing the hatch on the LM while doing EVA?

In the transcript of the Apollo 11 EVA on the Moon, Buzz Aldrin mentions closing the LM's hatch and being careful not to lock the two astronauts out. ...
80 views

### Solar system sized telescope and resolving details of the M87 black hole

In this video Katie Bouman mentions that an earth sized telescope needs to be used for getting images like the M87 Black Hole: Stellar distances are estimated using ...
96 views

### What is the meaning of the ROSCOSMOS logo?

ROSCOSMOS is the Russian state corporation for space exploration. Its logo is below. What is the official meaning or significance of the parts of the logo? ROSCOSMOS' main launch site (Baikonur ...
1k views

### What are/were the Customs requirements for astronauts?

When the Apollo 11 astronauts returned to US territory they famously went through US Customs where they listed "moon" as part of their flight routing: Was that a one-off? What are procedures today? ...
67 views

### Feasibilities and challenges of these Orion + commercial lunar lander scenarios? [closed]

Suppose that US politicians want to fund a moon mission without SLS, using only hardware that is working now in 2019, using Orion together with some future moon lander supplied by the private sector. ...
120 views

### Has an IV even been performed or attempted in space?

As many of you likely know, IV's are an important part of modern medicine. As more and more people go into space for longer periods, I would imagine it may become necessary for an IV to be ...
191 views

### How will SpaceX's Starship accommodate its 100 passengers from the effects of micro-gravity?

According to this Wikipedia article, Starship will take on average 115 days (3.8 months) to get to Mars and 150 days maximum (4.9 months). with an average trip time to Mars of approximately 115 ...
147 views

### Which unit system was used by german rocket scientists at NASA for calculations?

There were numerous german rocket scientists at NASA, see wikipedia 1, 2. They were used to the metric system which they used when working for the V-2 at Penemünde. But what unit system did they use ...
142 views

### Is vertical assembly worth the cost (Ariane 6)

Very recently, ESA released a new video showing the proposed Ariane 6 rocket being assembled. This mostly takes place in a large 'moveable gantry' building where the payload is placed on top of the ...
120 views

### What is the name of the 'register' that keeps track of all the satellites?

I imagine there must be a list of all the satellites ever launched and their coordinates. I can't find it on Google. My question is: What is the name of the 'register' that keeps track of all the ...
102 views

### What do these three historical IBM staff at NASA insignias designate?

The question Where are these historical IBM + Apollo related locations within NASA? What do these computers do? shows four images. Three of them show different IBM insignias on shirts of IBM staff. ...
126 views

### Where are these historical IBM + Apollo related locations within NASA? What do these computers do?

In the Fortune Magazine video IBM's Moonshot: Past and Future with the notes BM’s John Kelly reflects on Apollo 11’s historic mission and looks forward to what future technology will accomplish. ...
139 views

### What was the purpose of a Boyd Bolt?

The Apollo Lunar Surface Experiments Package (ALSEP) used a kind of spring-loaded bolt called a "Boyd Bolt", named after its inventor. There is a NASA page on it here. Can someone explain in plain ...
94 views

### Do satellites inject into a Hohmann transfer orbit in Low Earth Orbit or in Solar orbit?

Lets say we have a satellite wanting to go to Mars. Do satellites such as MAVEN inject into a Hohmann transfer orbit while in Earth's orbit, or do they go out of Earth's Sphere of Influence into solar ...
26 views

### Soyuz reentry acceleration profile with timing

I am looking for reentry Soyuz acceleration profile with timing. I was able to find graphs for ascent, but failed to find anything related with descent. The only thing I've got is Andreas Mogensen ...
180 views

### Does Chandrayaan 2 use gravity assist?

All of the descriptions I've seen online describing Chandrayaan-2's path to the Moon either explicitly or implicitly describe it involving a "gravity assist": The spacecraft will make use of the ...
25 views

### Rotation matrix from J2000 to ITRF2008

I want to rotate a vector from the inertial J2000 frame into ITRF2008. I am using the NASA SPICE library, which provides a rotation matrix from J2000 to ITRF93 (they plan to upgrade the library to a ...
1k views

### Were the Apollo broadcasts recorded locally on the LM?

I've previously asked about how the recordings from the Apollo missions were originally recorded, and then transcribed; but I forgot about the video as well! It's well known that for some of the ...
57 views

### How do you calculate the ∆v required to increase apoapsis to a certain height?

To calculate the ∆v needed to increase our apoapsis from a low orbit of 100km to 400km, we find the velocity at 100km using the semi major axis (which is 250km, in this case), and then find the ...
76 views

### What are the historical fastest and longest time between take off and orbit insertion?

The question is restricted to payloads having described at least 2 orbits. When watching launches, it appears that between launch and orbit insertion, the typical time interval is few minutes (...
2k views

### Was US film used in Luna 3?

This site claims that the USSR's Luna 3 probe, the first to photograph the far side of the moon, used special radiation and temperature hardened film taken from downed US spy balloons. Is this true? ...
14k views

### Why did NASA use U.S customary units?

NASA was using U.S customary units (inches, feet, nautical miles, pounds, tons, US gallons etc.) during the Mercury and Apollo programmes, and beyond. There are significant disadvantages to using U.S ...
8k views

### Are rockets faster than airplanes?

Rockets are fast. Faster than anything else somebody could fly with - at least intuitively to me. But - airplanes are fast too. A rocket typically flies vertically, an airplane mostly horizontally. ...
39 views

### What are the differences between various solar weather terms?

In preparation for my own possible question on solar weather, I searched for past questions on the topic. The past questions suggest that I am not the only person who is confused about the ...
38 views

### How to plot conic from Lambert solver

I am trying to solve for an optimal multi-gravity assist trajectory from Earth to Saturn using Matlab. I have already solved for the departure and arrival velocities from and to each planet using a ...
104 views

### why dose reentry speed need to be so fast [duplicate]

I have been wondering this since I was a kid. watching films of capsules and shuttles heating up and all that tile trouble and work that went into all. I would always wonder why they dont slow down ...