All Questions

7
votes
1answer
53 views

Asteroid impact on the Moon: which effects cause the flash?

It is most likely that there was an impact on the Moon during yesterday's lunar eclipse. I am trying to get some more understanding of this so that I could maybe do a more detailed video on this ...
4
votes
0answers
59 views

What are the effects of orbital reflectors and advertising on scientific observation?

There's a couple of startups and initiatives which are proposing "space billboards" which have been getting a lot of bad press recently. Most of the proposals involve a bunch of cubesats with large ...
4
votes
2answers
214 views

How did Lunokhod 1 become lost in 1971; in what ways did astronomers “look for it” after that?

The Smithsonian Magazine article Lost Soviet Reflector Found on the Moon says: There are actually five retroreflectors on the Moon: three placed by Apollo astronauts and two that sit atop Soviet ...
1
vote
0answers
16 views

Hohmann transfer trajectory and “porkchop plot”

The “porkchop plot” for a spacecraft flying from Earth to Mars would show contours of equal characteristic energy against combinations of launch date and arrival date. Assuming the spacecraft has ...
1
vote
1answer
21 views

Could Hubble observe the night side of the Moon?

IIUC the Hubble space telescope cannot observe the Sun lit side of the Moon. And Hubble is never pointed closer than 90 degrees towards the Sun. But this still allows for observing the night side of ...
0
votes
0answers
7 views

how to get true anomaly using subsatellite point (latitude)

I am working on an application which is using an orbit propagator. I have a satellite which sets its latitude using this orbit propagator. I want to change the latitude of the satellite by a new value,...
4
votes
1answer
428 views

Rotating in orbit?

Reading this question (Is the cupola, on the inside of the ISS, cold or warm to the touch?) prompted me to wonder about an object in orbit's orientation as it orbits its host object. For example, ...
3
votes
1answer
75 views

Is it possible to protect a Cubesat's electronics from 100g of acceleration?

I am currently researching the feasibility of setting up a coilgun that launches Cubesats for a paper. 1 cubesat per launch total payload mass <100kg.
3
votes
2answers
78 views

How would you move in low gravity without a suit?

Assuming your in a habitable environment, how would you move on a planet or moon with significantly less gravity without the encumbering EVA suit?
18
votes
6answers
8k views

Why can't they just drop a solar winch down from a shuttle and have planes fly up and clip things on?

Why can't they just drop a solar winch down from a shuttle and have planes fly up and clip things on? I know of the idea to have a space lift but the cable necessary is too expensive. Why can't we ...
1
vote
1answer
64 views

What are the limitations of monopropellant RCS thrusters in a re-useable spacecraft?

I understand the disadvantage of monopropellant is mainly dependent on the life of the catalyst. There is a possibility of catalyst failure due to it being subjected to catalytic poison and catalytic ...
0
votes
1answer
42 views

Help with my tensor tension; how to derive and calculate this rigid body gravity gradient torque?

Tensors make me tense. Imagine a long thin rod in a circular orbit. The gravity gradient will produce a net torque on the rod whenever it is not oriented parallel, or perpendicular to the radius ...
1
vote
2answers
214 views

What technical challenges would be playing this LP in (actual) space?

In the NYTimes article Third Man Records Sends a Vinyl Record Into Space an LP record player was designed and built to be flown in a balloon. It seems to have achieved only about 28.5 km which is ...
0
votes
1answer
124 views

How much does a swing-by change the orbit of the planet?

A friend of mine told me that one Voyager swing-by moved the orbit of Jupiter a foot closer to the sun. I understand that Jupiter was slowed by the gravity assist, but I figured it would be minuscule ...
1
vote
1answer
48 views

Was there once a semi-serious space-art project planning to use solar reflectors to put a spot of light on the crescent Moon?

Reading the question What are the effects of orbital reflectors and advertising on scientific observation and orbital debris? I am reminded of a story I read a while ago about an even in the past, ...
1
vote
1answer
47 views

What psychiatric and psychological tests do people need to pass to become astronauts?

I am writing a short film about an astronaut during re-entry to earth. Part of the conflict I wrote is that the astronaut could not pass the mental tests required. Could anyone tell me any tests ...
39
votes
7answers
2k views

How do we know the Apollo Moon landings are real?

Since about 1976, conspiracy theories denying the Moon landing and claiming it was all faked have cropped up. As a website devoted to answering questions about space exploration, we receive questions ...
15
votes
3answers
4k views

Why was the engine of the launch vehicle recently tested in Iran “not a very good missile engine”?

The NPR News item What's Iran Up To With Recent Rocket Launch Attempt? by NPR's Geoff Brumfiel, about a recent launch test in Iran includes the following: Earlier this week, Iran attempted to ...
1
vote
1answer
94 views

Who were the major manufacturers of the Apollo 11 rocket — STILL ALIVE?

Organizing an exhibition around photographs from the 1969 launch and wanted to invite manufacturers.
1
vote
1answer
49 views

Why did the S5.2/9D21 rocket engine engine have pyrocharges?

In a recent question, an answer showed a diagram of a Soviet S5.2/9D21 rocket engine. According to the diagram, there are four pyrocharges (3, 7, 24, and 27) in the engine. What is the purpose/...
10
votes
0answers
297 views
+100

How are the Voyagers' thrusters configured in a novel way to minimize accelerations along Earth-spacecraft axis?

I've just read in Eshleman et al 1977 Radio Science Investigations with Voyager that the voyagers have: ...a novel attitude-control thruster configuration that minimizes accelerations along the ...
15
votes
4answers
5k views

Are there any known reasons why there are no spaceports in the European Union?

As far as I know, there are no spaceports in the European Union. Why is it so?
17
votes
2answers
11k views

Apollo communication between the Earth and Moon

How was it possible for astronauts to send back tv/radio signals to earth from the moon? I have just been teaching my son about waves behavior and understand that radio waves are reflected back to ...
6
votes
0answers
154 views

What is the smallest launch vehicle that has put a satellite in a geostationary orbit?

Minotaur V might become a candidate for the smallest current launcher to put a payload in GEO, but it has only launched LADEE yet. The first satellite in GEO seems to have been Syncom 1 which launched ...
1
vote
1answer
477 views

Will JAXA try again to launch TRICOM-1 with the “world's smallest orbital rocket” SS-520-4 again?

From the Spaceflight 101 article Experimental Launch of World’s Smallest Orbital Space Rocket ends in Failure: SS-520-4 lifted off from the Uchinoura Space Center in Japan’s Kagoshima prefecture at ...
9
votes
2answers
2k views

What is/was the smallest orbital launch system, by total mass?

What is (or was, if it's no longer in use) the system with lowest launch mass, capable of putting (any) payload in (or reaching) LEO? "How small" did we get with orbital flights? (and yes, I realize ...
-1
votes
2answers
585 views

Does SpaceX plan to enhance/change the genome of space colonists to speed up the adaptation process to the living conditions on Mars? [closed]

My understanding of biology is that all living organisms adapt to the environment around them. I would even say the environment shapes the very essence of an organism. Gravity alone is a huge factor ...
4
votes
0answers
59 views

Falcon 9 2nd stage pusher; how far does it continue to extend as it accelerates separation?

I've just watched Scott Manley's video SpaceX's Water Landing Reveals Rocket "Secrets" (or, What We Learned from CRS-16) (again) and he mentions the second stage "pusher" in the center of the view (...
3
votes
1answer
91 views

Help with Scott Manley's rigid body dynamics narration

I've just watched Scott Manley's video SpaceX's Water Landing Reveals Rocket "Secrets" (or, What We Learned from CRS-16) (again) and there's some rigid body dynamics in there where I'm not sure I am ...
1
vote
0answers
64 views

What is wrong with my orbit sim equations? How can I fix them?

Edit: Partial question: The object now moves in an ellipse like it's supposed to, but it orbits around a different point than I intend. How can I make it orbit around a particular object at a point? ...
10
votes
1answer
138 views

How will SpaceX Starship deploy its payload?

Most modern orbital launchers like the SpaceX Falcon9 have their payload at the front covered by a fairing which splits in half, ejecting the fairings and exposing the payload for deployment. With ...
1
vote
1answer
169 views

How much fuel would the Starship need to LAND 100,000kg on Earth?

The SpaceX's Starship is in orbit, empty payload. Magically, 100,000kg of payload appears inside the ship, setting aside all the logistical questions of how it got there. Now it needs to deorbit and ...
11
votes
1answer
1k views

What is this red gas at the exhaust of the Long March 3B rocket during liftoff?

While watching today's live stream of the launch of the China National Space Administration (CNSA) Long March 3B rocket carrying Chang'e 3 lunar exploration probe and the Yutu rover to the Moon, @...
9
votes
2answers
608 views

If China wanted to hush the purpose of a space launch, can it be inferred outside of China?

What I had in mind is that China's territory is rather large and they could place a launch site deep within its territory. Flow of information is tightly controlled as it is with the Great Firewall of ...
19
votes
3answers
7k views

How can Mars have dust storms with such a thin atmosphere?

Mars, as I understand, has a very thin atmosphere. However, it still has weather like this: What causes the thin atmosphere to move fast enough to cause such a monster wave of dust?
3
votes
1answer
47 views

Luna artificial satellite eclipses

Have we been able to see the shadow on the Moon's surface of any artificial satellites that orbit the Moon?
5
votes
2answers
300 views

What forms of water ice have been observed and verified in the solar system?

The cool plot in this answer (from here) got me thinking about the more than sixteen distinct forms of ice, and how many of them have been actually seen to occur naturally in the solar system. There ...
1
vote
1answer
35 views

What lateral and rotational accelerations can a spacecraft achieve?

I've found information like the Space Shuttle Orbiter has so many thrusters each generating so much force to maneuver "with redundancy" in orbit. But without knowing something like how many thrusters ...
4
votes
1answer
66 views

Launch window for the Apollo Lunar Module?

If something would have gone wrong after a successful Moon landing requiring to ascent as soon as possible, what about the launch window for the lunar rendezvous maneuver? Could they ascent at any ...
5
votes
3answers
272 views

Has any man-made satellite or space vehicle ever been hit by a natural meteoroid?

For precision I'm excluding artificial meteoroids and satellite debris (which is discussed in another question) of all kinds. I'm also considering collisions large enough to produce a noticeable ...
3
votes
1answer
181 views

What did New Horizons photograph that was close enough to be out of focus?

The picture below shows a Kuiper Belt object and a number of stars. It was recently taken by the New Horizons probe and published by NASA. The arrow points at the KBO and the rest of the bright ...
3
votes
0answers
32 views

Cost of an earth observation cubesat satellite like Planet-s Doves?

With the Cubesat standard and more and more components being available off the shelf, this should really bring down the price of building a (simple) earth observation platform. I am curious how low a ...
1
vote
0answers
39 views

What causes these plume features on Delta IV Heavy?

Just catching up on the Jan 19th launch of NROL-71 on board the Delta IV Heavy and I noticed these very prominent features in the exhaust plumes, beginning around the time the centre core is throttled ...
5
votes
0answers
233 views

How well can the ISS attitude control system detect periods of astronaut activity?

The question Why doesn't ISS start to spin if people walk inside? is a good one partly because it has attracted several good, informative answers. One of them is particularly intriguing because it ...
-2
votes
2answers
91 views

Why didn’t the astronauts on the moon ever get out of breath? Even while running, or falling down?

My question is, even with the demand of learning how to walk and all the falls and and bumbling around of the astronauts, they never ran outta breath? Maybe in the newer missions they caught this and ...
10
votes
2answers
3k views

Why will the Orion system land on water, while the Soyuz lands on land?

I wonder why the Orion Multi-Purpose Crew Vehicle will only allow ocean landings while the Soyuz spacecraft is capable of landing on land? Also, what mode of landings does the Chinese space program ...
40
votes
5answers
11k views

Why haven't more spacecraft/satellites been hit by debris?

It is touted by the media that space is becoming more dangerous and risky due to an increase in space debris. Why haven't more craft been hit by the debris? I presume that it is not at a critical ...
2
votes
1answer
186 views

Is there a space-certification procedure used by commercial spacecraft manufactures for electronic components?

For electronic components at the level of say electrolytic capacitors, ethernet connectors connectors, and possibly in the future fiber optic connectors/electrical signal interfaces are there well ...
5
votes
0answers
39 views

Does NASA still plan for the Mars Ascent Vehicle to burn wax from the surface to orbit?

The NASA news item From Pedicures to the Peregrine Rocket, Paraffin Wax Proves Its Worth says: The paraffin-based fuel also works under challenging environmental conditions, like the very low ...
6
votes
0answers
281 views

Why NASA's sudden (apparently) interest in Wax hybrid engines? Which property is so attractive now?

I've just read the NASA news item From Pedicures to the Peregrine Rocket, Paraffin Wax Proves Its Worth. The project started when researchers at Stanford discovered that paraffin fuel burns three ...

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