All Questions
18,616
questions
-6
votes
1
answer
168
views
Windmills in Space [closed]
What if we put a windmill like we use now in space like on moon or a space station so its attached to the surface and since we have no wind we use air tanks in the blades to rotate, everytime it slows ...
3
votes
2
answers
214
views
What did I see? Multiple "satellite" flares
I came across this page this evening after witnessing around 15 what looked to be satellite flares in the same region of sky within about ten minutes. All of the objects flared multiple times with a ...
- 31
12
votes
3
answers
5k
views
What assumptions were made about the sphericity of the Moon for the Apollo program?
I've just been reading about the Apollo program.
Apollo 8 seems to have gone into a fairly circular lunar orbit 69 miles at perigee.
Apollo 10 was pretty much similar, although they dipped down with ...
- 343
3
votes
1
answer
226
views
Where can I find the video of Apollo 16 floodlight mistaken with a UFO?
So, a few years ago (2004) NASA showed that a picture of a supposed UFO captured by the Apollo 16 astronauts through the window of the Command Module was in fact the floodlight protruding from the ...
- 2,501
1
vote
0
answers
79
views
How many tonnes of cargo are stored on the International Space Station?
I think I read somewhere that SpaceX's Starship should carry 100 tonnes to the moon, and that this amount of mass was greater than the total cargo on the ISS, but I can't find a reference confirming ...
- 713
17
votes
1
answer
2k
views
Why does the Psyche Spacecraft use cold gas thrusters?
In a recent article on SpaceNews they write
[There exist] nitrogen cold-gas thrusters that orient the spacecraft.
This seems like an odd choice for me, considering it is a multi year mission that ...
- 3,566
4
votes
1
answer
255
views
What is the significance of a heat flux value of 1135 W/m^2 when jettisoning the payload fairing? [duplicate]
I have seen that many rockets jettison their payload fairing at an altitude where the aerothermal heatflux is leass than or equal to 1135 W/m^2. What is the reason behind considering this particular ...
- 41
2
votes
1
answer
128
views
Can I move Hyperion to Mars with fusion rockets?
I'm working on a SciFi story set roughly in 2100 that takes place both on the moon and Mars. One plot point hinges on terraforming Mars, the biggest stumbling block being its lack of water and ...
6
votes
1
answer
258
views
How does NASA ensure nobody else communicates with probes? [duplicate]
We often hear about how various parts of Voyager have been turned off or on, or how course corrections have been made.
How does NASA know that nobody else on Earth can send instructions to a probe? It ...
- 163
1
vote
1
answer
72
views
LEO Satellite Service / Coverage Time Calculation for a Ground User
I want to determine the time interval during which a ground user is in the coverage of a particular LEO satellite. I only have knowledge of the user's geographical location and the satellite's TLE (...
- 43
2
votes
1
answer
72
views
TLE propagation, I don't understand which time should I use in (t - t_0)?
I'm trying to plot ground tracks with the help of TLE data. However, there are some equations that contain "times", and I can't understand which time I should use and format. Like for ...
- 43
1
vote
1
answer
65
views
Gibbs' method and position vectors' reference frame
As mentioned on this website https://www.studeersnel.nl/nl/document/technische-universiteit-delft/flight-orbital-mechanics-and-propulsion/chapter-05-preliminary-orbit-determination/4604099, we need to ...
- 13
6
votes
4
answers
335
views
Deorbit ISS vs. Preserve ISS as raw materials for ISM?
Recent news:
NASA Seeks Proposals from US Industry for Station Deorbit Spacecraft (ISS)
NASA has released a request for proposal from U.S. industry for the U.S. Deorbit Vehicle (USDV), a spacecraft ...
- 161
1
vote
0
answers
192
views
Fastest time to Moon for Starship
What is the fastest time to the Moon possible with Starship in the near future, assuming there is orbital refueling?
Is sustained acceleration and then deceleration possible at say 0.25G, to reduce ...
- 313
0
votes
0
answers
82
views
How to read .eph (GPS Ephemeris binary data) sent by the receiver
My GPS receiver can share ephemeris info as binary data. The queried data is having .eph format. I tried to open it in Notepad but seems unreadable (gibberish). Is there any specific software to open ...
- 1
0
votes
0
answers
48
views
Hypersonic dynamic shift in large vs. small lifting bodies
Background:
Lifting bodies have been tested at small scales, though not during re-entry. For instance: the NASA HL10
Such Lifting-Body designs are seemingly here to stay with craft such as Dreamchaser ...
- 991
3
votes
3
answers
997
views
Would orbital ring platforms affect the orbit of a planet?
If we built an orbiting platform of sufficient mass (let's say, made from harvested asteroids) that was anchored at both poles of the planet it surrounded, would such an addition to the planet's mass ...
- 31
10
votes
1
answer
2k
views
Packing Osiris Rex capsule after landing
What was the procedure for packaging SRC Osiris Rex after landing? How to keep it clean, with no dust or sand? Why was it not packed on a clean surface like a table?
- 101
-4
votes
1
answer
221
views
How does SpaceX prevent fuel from cluttering together in zero G [closed]
What is the solution to stop fuel inside starship collecting in center of the tank during zero G flight? Here is a rough sketch of starship with rudimentary diaphragm system to control flow of fuel ...
2
votes
0
answers
180
views
Escaping Earth - how could one attempt to find the best solution to this trajectory optimization problem in practice?
If there is a satellite in low Earth orbit, with a limited delta-v budget (but high enough to escape Earth) and limited delta-v-rate (thrust), how could one find an acceleration schedule and ...
- 171
1
vote
0
answers
42
views
Surface Resource Distribution Across the Orbits of the Saturnian Moons
I've posted questions before related to ISRU and/or resource harvesting in the Saturn system, given how low the velocity change is for inter-moon transfer.
What resources are available to turn into ...
- 991
3
votes
1
answer
151
views
Can a ship's thrusters amplify a gravity assist?
If a ship successfully absorbs a planet's kinetic energy to increase its speed, can it add to that speed by firing its thrusters? Thank you very much.
- 31
2
votes
1
answer
122
views
GMAT LEO spacecraft simulation
I started using GMAT, I have to design an LEO of an AEOLUS Satellite and I have the TLE of the launching. My question is how do I plug the TLE numbers into the spacecraft section (Keplerian element ...
- 21
9
votes
1
answer
3k
views
What are the movable-plastic-bag-looking things on the nose of Shuttle?
I was watching the last launch of Space Shuttle Atlantis (STS-132) and noticed some objects that moved during the launch. I was curious about what these objects were and why they were positioned that ...
- 501
8
votes
1
answer
192
views
First water deluge system?
Does anyone know what the first use of a water deluge system was?
I've done some light googling and discovered that the Titan II ICBM rocket silos (first built in 1962) used a water deluge system, but ...
- 171
11
votes
4
answers
6k
views
Why would astronauts need a wristwatch and a separate timer?
Watching this image used in this question
Why would astronauts in SpaceX's Crew Dragon need two separate timing devices: one portable digital timer, and one wristwatch, rather than carrying into orbit ...
- 4,218
0
votes
0
answers
155
views
Live_ISS_Stream stopped?
so I've come across this video, 11 hours of ISS transmissions during 2021 ASAT incident by Russia. The description says the footage was archived from this IBM stream site, so I've looked to see if it ...
- 39
30
votes
1
answer
7k
views
Reasons behind Soviets Using Prolog Programming Language for Buran Space Shuttle?
I was reading a post related to the operating system of American Space Shuttles, then wondered what might Soviets have used. I found a CIA document and several forums saying that Prolog was used in ...
- 501
2
votes
0
answers
84
views
Non-Cryogenic Propellant Transfer
I know there are programs like the Rocket Lab CryoSat, but I was wondering if there have been any tests of non-cryo propellant transfer?
I know the Space Station refuels with a storable hypergol, but ...
- 991
1
vote
1
answer
265
views
What network does the Chandra X-ray Observatory satellite use to communicate with Earth while staying in its orbit?
From a NASA fun facts website How do satellites communicate?:
How do satellites communicate?
Satellites communicate by using radio waves to send signals to the
antennas on the Earth. The antennas ...
1
vote
0
answers
60
views
How to access satellite & debris data categorised by intended purpose?
I'm working on an art project which requires satellite data (active, inactive, as well as debris), so I was on Space Track. Does the NORAD ID or some other field help retrieve information about the ...
- 11
10
votes
1
answer
2k
views
What is the name of NASA's program to prevent back-contamination by crews returning to Earth?
I remember reading a Wikipedia article that in the initial years of space exploration NASA had a standing crew of bulldozers to bury any landing site or research facility exploring material from ...
- 499
2
votes
1
answer
196
views
How does JUICE navigate autonomously
Introduction
To kick things off, I'd like to introduce myself as a 23-year-old novice learner when it comes to space exploration but I've been listening to astronomy-specific podcasts since 2022 and I'...
- 23
1
vote
1
answer
191
views
how to procure a Launch vehicle for injecting a cubesat into LEO at LOW COST?
Me and my team are working on sending Cubesats just beyond the Karmann line. For which we obviously need a launch vehicle and would like to procure one or if possible build one. If any aerospace ...
7
votes
1
answer
219
views
When you burn retrograde, will you reach periapsis sooner or later?
Say you have two spacecraft in identical orbits. Say at a point after apoapsis and before periapsis one of the spacecraft burns retrograde to lower its periapsis, and the other spacecraft does nothing ...
1
vote
0
answers
80
views
How to approximate the force generated by Falcon 9 grid fins?
I'm interested in approximating the force generated by the grid fins on a Falcon 9 rocket during its descent phase. However, I currently lack specific data and equations for this calculation. Can ...
1
vote
1
answer
158
views
Could a skyhook with double pendulum catch a payload with zero velocity?
It's my understanding the the tip of a rotating skyhook would be travelling at ~3.6 km/s (Mach 10), which presents a major problem.
Could this be overcome by attaching a second, smaller, also rotating ...
- 119
6
votes
1
answer
175
views
Comparing Japan's SLIM and India's Chandrayaan-3 trajectories
I was reading this SpaceNews article on the launch, which states:
SLIM won’t be taking a direct route to the moon. After a lunar transfer orbit burn, it will make a lunar flyby, heading into a wide ...
- 1,329
4
votes
1
answer
116
views
Geo satellite - antenna gain contours to heat map in STK
I am using STK to show antenna gain contours on the ground from a transmitter on a sensor on a geo bird that is tracking a receiver on the ground. With good resolution I can create great images that ...
- 41
4
votes
0
answers
119
views
Atomic oxygen and UV Radiation qualification tests for a cubesat
I'm the Assembly, Integration and Verification Engineer of a cubesat project developed by students. Currently I'm trying to create the specifications for our payloads upcoming (mon)atomic oxygen (ATOX)...
0
votes
1
answer
80
views
Semi-Cryogenic HTP/LH2 engine?
Also see HTP as oxidizer for main propulsion
(for more info on history of H2O2/HTP in rocketry)
Note: HTP and H2O2 will be used interchangeably
I know the Black Arrow LV (The first orbital lipstick) ...
- 991
7
votes
2
answers
435
views
What are these things on the side of the GSLV Mk 3 SRBs?
Circled in green
Images found by looking up “gslv mk 3”
1
vote
1
answer
100
views
Meeus on the Positions of the Satellites of Jupiter
Ex. 44.a of Meeus Astronomical Algorithm, Second Edition, provide the position of the Galileans on December 16 1992 at 0h UT (p.311/488).
Procedure 1:
For Io, in terms of the Jupiter's equatorial ...
- 31
1
vote
0
answers
86
views
How do you find the burn-time of a specific solid rocket fuel?
I read this post about finding the propellant mass needed to reach a specific altitude: How do you find the propellant mass needed to reach an inputted altitude?(altitude at end of burn plus altitude ...
- 11
3
votes
1
answer
118
views
How will the DAVINCI probe manage its temperature during the descent to Venus' surface?
The DAVINCI mission, arriving at Venus in 2031, includes a probe that will collect data as it descends through the planet's atmosphere.
The descent will take about an hour and Stephanie Getty, deputy ...
- 2,451
2
votes
0
answers
79
views
Semi-interdependant Jovian Colony [closed]
Given the low $\Delta v$ needed to transfer between the moons of Jupiter even just between the Galilean large moons, and the distribution of heavier molecules and atoms towards the inner system (Io + ...
- 991
2
votes
1
answer
83
views
Combustion stability for the second stage of Sea Dragon
I was listening to a video about SHLV's (Super Heavy Launch Vehicles), and Sea Dragon's first stage engine was mentioned.
In terms of combustions stability, the suggested fix would be large combustion ...
- 991
2
votes
0
answers
50
views
What is the A in the mass flow rate formula for solid rocket propellants? How do I get the chamber pressure? [closed]
I believe the mass flow rate formula for solid rocket motors is:$$\dot{m}=p_pA_br$$ What is $A_b$ in this case. Is it the cross-sectional area of the hole in the grain? What is there is a nozzle? What ...
- 221
4
votes
1
answer
62
views
Could you see a probe or space ship with a DS4G ion propulsion thruster with a telescope? Would you need IR or UV?
I'm wondering what would be observable to an astronomer if one knew where to look for a distant space craft with a powerful ion engine such as a Dual-Stage 4-Grid (DS4G) electrostatic thruster. In the ...
- 141
15
votes
4
answers
4k
views
Do all artificial satellites have engines?
Novice question. A few days ago I watched a TV documentary about Virgin Orbit’s failed mission earlier this year to send satellites into orbit from Spaceport Cornwall. One of the satellites shown ...
- 253