All Questions

3
votes
0answers
12 views

Why are images from DSCOVR EPIC unavailable for certain dates?

I am in love with the images available at https://epic.gsfc.nasa.gov/ taken from the DSCOVR satellite. I am curious though as to why some dates are unavailable to select. The calendar date picker ...
2
votes
1answer
41 views

Did Apollo-11 astronauts rehearse their photoshoots on Earth?

After asking Have astronauts in space suits ever taken selfies? If so, how? I started to think about the photo below, and especially the cropped and rotated section, where I always get confused by ...
0
votes
0answers
8 views

Has VLBI been done using any space-based receivers besides Spektr-R?

As discussed in Infrared space interferometry - Why isn't it being done? the space-based radiotelescope Spektr-R has been used in Very Long Baseline Interferometry or VLBI. See also What are Spectr-R'...
1
vote
0answers
16 views

How is Spektr-R doing these days?

Under the question What are Spectr-R's major contributions to radio astronomy that could not have been done from Earth? there is a new comment that points (again) to the BBC News article Spektr-R: ...
2
votes
3answers
60 views

How many spy satellites could be destroyed before the debris field would be too massive to launch moon or mars manned missions?

Obviously this is very statistical. Basically I'm looking for an order of magnitude. One geostationary satellite would cause a pinball effect or would it be more like 10 satellites? I'm concerned ...
1
vote
1answer
96 views

Why does this satellite collision debris field look like a big “X”?

This answer to the question Whats the protocol if two satellites collide? shows the image below, and I don't understand the shape. I would have expected two "jets" of debris, each projecting roughly ...
6
votes
1answer
108 views

Which rockets use(d) solid-fuel upper stages?

The Antares is unusual in that it's using solid-fuel in the second stage. I was surprised about that and a couple of questions immediately popped up which are already covered on this site: How can a ...
0
votes
0answers
35 views

How were the geodetic and geocentric latitudes of the Space Shuttle defined and calculated?

The image below is cropped from https://i.stack.imgur.com/4XFaJ.jpg as described in this answer. It shows a geographic state of a space shuttle at a given instant in time. There is only one value for ...
3
votes
0answers
42 views

How do you find the temperature of an orbiting aluminum sheet 10x10 cm

I'm trying to find the temperature of a CubeSat in orbit at 140km. I'm trying to use the Stefan-Boltzmann law but don't know how to incorporate the energy from sunlight. I'm using this as a check for ...
4
votes
1answer
137 views

What is the most expensive part of a rocket?

I want to say fuel is, but this Question Why isn't stainless steel used for rocket engines? has got me thinking about cost in the long run. What part commonly found on most rockets cost the most ...
2
votes
1answer
60 views

How would a hybrid rocket work?

How does a solid fuel liquid oxidizer hybrid rocket work? How do they throttle them up and down? Virgin Galactic plans to use a hybrid engine, and I was also wondering how they were planning to store ...
21
votes
7answers
3k views

How would a mousetrap for use in space work?

To the question If mice escaped on the International Space Station, could they live and thrive? both the answer and comments point out that while mice escaped from an experiment might survive a while ...
5
votes
1answer
105 views

What influence did Arthur C. Clarke have on early satellite development?

Partially inspired by this uhoh question on SciFi.SE In writing up my answer, I came across this interview Clarke gave to NPR in 2008 where this quote is made While Clarke came up with the idea of ...
3
votes
2answers
120 views

What is the lowest latency achievable in reliable Earth - Moon communications?

I know that radio waves travel at the speed of light in vacuum so the minimal latency to communicate between Earth and Moon would be about 1.25 second each way. This latency figure will then increase ...
5
votes
2answers
161 views

Fast spining solar cells to clear Martian dust possible?

I've seen a fast spinning glass wheel used in front of a camera to clear away water, dust or ice. Could Solar panels be made circular and spin to clear dust off of them in the same way may? Could ...
2
votes
2answers
103 views

Could electricty be generated from a Martian dust storm?

This helicopter is producing static electricity from the blades moving through the dusty air. Along with the electricity provided by wind generators could additional power be created this way from ...
3
votes
2answers
2k views

Can we see the USA flag on the Moon from Earth? [duplicate]

Is it possible one day to see landing site flags on the Moon from Earth or from space without having to land using a telescope as technology progresses? Highly Related: Were the Apollo lunar ...
4
votes
2answers
47 views

Where can I find examples of orbital state vectors?

I'm currently trying to write a program that can calculate orbital trajectories. The goal is to take any orbital state vector (position, velocity) and convert it into Keplerian orbital elements, or ...
2
votes
1answer
129 views

Does sunlight warm an astronaut's face during a spacewalk?

I understand astronauts' helmets have dichroic optical filters to protect from many different frequencies of EM radiation. Do the filters prevent the astronaut from feeling warmth on their skin when ...
3
votes
2answers
121 views

Were there any spacecraft not configured for a spacewalk?

Since the first spacewalks were preformed, have there been any spacecraft that didn't allow for a spacewalk?
11
votes
2answers
2k views

Apollo command module space walk?

Could the Apollo astronauts have done an eva, from the Command Module, during the flight to or from the Moon?
12
votes
1answer
2k views

Why did the Falcon Heavy center core fall off the ASDS OCISLY barge?

On the second flight of the Falcon Heavy, they successfully landed the side cores at LZ-1 and LZ-2, and the center core downrange on the ASDS Of Course I Still Love You. Reports have come in that ...
10
votes
1answer
460 views

If mice escaped on the International Space Station, could they live and thrive?

The SciNews video Mice aboard the International Space Station is fun to watch for those tired of the same old rocket launch videos. Behavior of mice aboard the International Space Station 20 ...
1
vote
0answers
65 views

Could the BFR Tanker be used as an artificial gravity counterweight for interplanetary travel?

An alternative storyline to the Mars transport architecture: Tankers refuel starship, last Tanker gets mounted on the Starship for the Mars orbital injection burn, once on a Martian trajectory tanker ...
5
votes
2answers
100 views

Flat-spin transition manoeuvre: why is the angular momentum not constant?

In an article by Rahn and Barba, in which a flat-spin transition manoeuvre is investigated, the following figure is presented: I'm trying to reproduce this figure by integrating the following coupled ...
0
votes
1answer
56 views

Does the arrow in this SOHO trajectory animation point heliocentric prograde, or towards the Sun?

This answer links to this NASA page. The first video shows the two STEREO spacecraft use two and three passes by the Moon to leave Earth orbit and enter into an orbit around the sun. Below is a GIF ...
6
votes
1answer
340 views

Does the US Navy guard SpaceX drone ships and make sure bad actors don't abscond with critical technology on the high seas?

SpaceX loses the center core of its Falcon Heavy rocket due to choppy seas While I thought my question How vulnerable could space launch vehicles be to a “lone gunman”? was just my tangential ...
2
votes
1answer
82 views

How would 2 spacecraft be launched to be in sync in opposite directions?

How would 1 spacecraft be launched to have a prograde orbit and the another be launched retrograde to have a mirrored orbital path around the sun or otherwise? Would the 2 spacecraft launch together ...
1
vote
1answer
52 views

How would 2 JWSTs make stereo pictures?

Could 2 JWST be launched in opposite directions to provide stereo vision? Would a stereo picture provide any benefit? https://space.stackexchange.com/a/35402/18879 Related: How will JWST manage ...
12
votes
2answers
1k views

Temperature of a satellite orbiting in low Earth orbit

I am working on a project for science fair that involves a deployable component that will not be heated on a CubeSat. I am trying to find data for the skin temperature of a satellite (or the ISS) over ...
3
votes
0answers
67 views

How do they know some lakes on Titan are 100 meters deep?

JPL News item NASA's Cassini Reveals Surprises with Titan's Lakes NASA's Solar System Dynamics New item Cassini Reveals Surprises with Titan's Lakes point out that some lakes on Titan have been ...
1
vote
0answers
45 views

Details about traveling from EM-L2 to SE-L1

Would the optimal time to launch be when the Moon was on the opposite side of the Earth from the Sun. What direction would be optimal leaving EM-L2, radially away from the moon? Is the last line of ...
4
votes
1answer
136 views
+100

Is TESS really lost? What does Celestrak mean exactly?

From this answer to the question What artificial satellite has the farthest orbit around the Earth?: I found the following "far out" spacecraft: TESS (Transiting Exoplanet Survey Satellite) ...
29
votes
6answers
8k views

Why aren't air breathing engines used as small first stages?

I am wondering why we don't use jet engines as first stages. Most small rockets, like the Electron, can lift off with a small thrust. In the Electron's case, 192 kN. Why can't we replace the 9 ...
2
votes
0answers
63 views

Space-X Canaveral launch question

In the past, I could see space shuttle launches from my front door on the gulf coast of Pinellas County by looking due east on a clear day or night. I have tried to catch Space-X launches a couple ...
1
vote
0answers
32 views

Are geostationary orbits impacted by changes to earths magnetic field?

Would geostationary satellites be pushed to different orbits by changes in the magnetic filed or even more so by shifting poles or even a reversal?
1
vote
1answer
76 views

What kind of signal Voyager 1 is sending to us?

I was reading on wiki about Voyager 1 mission and I found very interesting! One thing I did not manage to find: what is the signal Voyager 1 is sending to us? Is it simply a sinewave or something more ...
1
vote
0answers
78 views

What would be payload capacity of reusable Falcon 9 if there was no atmosphere on Earth?

Reading this question and answers, I wondered what would happen if there was no atmosphere, everything else being the same on Earth. What would be the payload capacity to LEO of Falcon 9 in reusable ...
17
votes
2answers
3k views

What are the pros and cons of Aerospike nosecones?

Some rockets, mainly (only?) ICBMs have Aerospike nosecones Why are they preferred in lieu of traditional nose cones? Illustrations: An aerospike nosecone on a trident ICBM Video including the ...
3
votes
3answers
208 views

How good is Stratolaunch vs Falcon9 as a first stage?

With the Stratolaunch flying this week I was interested in seeing how good it was compared to a Falcon9. I figured comparing energy contribution would make sense. The stats as best I can find: ...
6
votes
2answers
246 views

Do we know why communications with Beresheet and NASA were lost during the attempted landing of the Moon lander?

I was watching the livestream of the SpaceIL team when they were attempting to land Beresheet on the Moon. As near as I can remember, at around an altitude of 15km above the surface, the SpaceIL ...
1
vote
0answers
45 views

Operator access to a cube satellite or any educational satellite

I would like to have free or low-cost access to an existing CubeSat (educational satellite) for educational purposes. I wish to familiarise myself with the end to end command & control activities, ...
4
votes
2answers
76 views

Payload Specialist Training

How rigorous was training for Space Shuttle payload specialists? These astronauts were not selected from the normal astronaut pipeline, but instead were people with clout (politicians), PR ...
-4
votes
0answers
58 views

Apollo 11 Mission to the Moon [duplicate]

Where are the stars in the Apollo 11 photographs. It look unnatural without stars with a black celestial background.
5
votes
0answers
541 views

Why does the Event Horizon Telescope (EHT) not include telescopes from Africa, Asia or Australia? [migrated]

The Event Horizon Telescope seems to include these radio telescopes currently: Image by European Southern Observatory (ESO)/O. Furtak; CC-BY 4.0-licensed, see the source on Wikipedia Commons and the ...
3
votes
0answers
54 views

What is the physics behind a rocket landing on a celestial body with an atmosphere?

I would like to know the different physics concept I would need to land a rocket being in orbit. I know the timing is important to leave it, how can one find this out ? Then how to compute the ...
0
votes
1answer
123 views

What is the most promising interstellar propulsion method? [on hold]

What interstellar propulsion system has the highest potential for being the safest, most efficient, and can get around to the nearest stars, within a human lifetime (say reach 20–50% the speed of ...
5
votes
1answer
133 views

Can Amateur Rocketeers use Liquid Nitrogen Dioxide as oxidizer?

I was reading similar question as mine here. But no one talked about Nitrogen Dioxide (NO2). Its boiling point is 21C. So easy to store. But how easy it is to handle compared to Hydrogen Peroxide or ...
3
votes
0answers
61 views

Are these two length scales in FH exhaust plumes real, understood, and distinct?

The Ars Technica article We can admit it—we’re dazzled by the controlled fury of the Falcon Heavy includes a beautiful photo of the exhaust plume produced by the 27 engines of a Falcon Heavy launch. ...
2
votes
2answers
134 views

Delta V to get to the Sun-Earth Lagrange Point 1?

For any of these starting positions, GEO, GTO, EM-L2 or EM-L4/5, which would require the least delta-V to get to Sun-Earth L1? How much delta-V would it require? Would this chart help in identifying ...

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