All Questions
17,180
questions
3
votes
1
answer
17
views
What makes aluminum aerospace grade?
So what is aerospace grade aluminum? Aerospace grade and regular aluminum or both aluminum. Do they have a different composition or strength? What makes one aerospace grade?
1
vote
1
answer
27
views
Is there any chance that Opportunity survived, but NASA kept pinging it at the wrong time?
In 2018, NASA's beloved little Opportunity (oppy) was declared dead after a dust storm "killed" it. It may still be OK, but when NASA began recovery effort, they pinged oppy when it was ...
- 69
2
votes
0
answers
44
views
How does US crewed launch abort coverage "jump" the ocean in an instant?
As I understand things, the Commercial Crew Program stipulates full abort coverage from pad to orbit. An abort to the middle of the Atlantic ocean is understandably not acceptable.
Watching the OFT-2 ...
- 8,115
1
vote
0
answers
12
views
NASA GMAT Hardware in the Loop testing
We are currently evaluating various Mission Analysis & Simulation tools, one of which is NASA's GMAT (2020). One of our requirements is for the tool to support HITL testing. However, i am unable ...
- 111
0
votes
0
answers
21
views
Between two spacecraft, differential phase measurements are used to achieve high relative bearing accuracy. How is this done?
Based on my understanding, as spacecraft A transmits a signal to spacecraft B, multiple receivers on spacecraft B receive the signal. When spacecraft B changes its orientation, the phase differentials ...
- 1
2
votes
1
answer
67
views
How many times has SpaceX reused Falcon 9 first stage until now? [closed]
How many times has SpaceX reused Falcon 9 first stage until now?
Not about the possibility. I want to know the current progress with the Falcon 9 first stage.
- 21
8
votes
1
answer
561
views
Why was the Atlas V's SRB kept attached for 1 minute after burnout in the OFT-2 mission?
In Boeing's OFT-2 mission, an Atlas V is the launch vehicle. The solid rocket booster burns out at T+ 1:35 minutes, but the boosters are jettisoned at T+ 2:40 minutes. Why are the boosters not ...
- 2,251
1
vote
0
answers
97
views
Why is my C++ code for an orbit propagator wrong?
I tried making an orbit propagator C++ code. Its values seem to be propagating evenly but still I get a straight line orbit instead of an elliptical one. Why?
...
0
votes
1
answer
52
views
How to calculate the max mass and speed of an asteroid capturable by gravity assist?
After reading this question and the answers, I am wondering about the limits of slingshot method to capture an asteroid into a planet orbit.
Is it possible to calculate if an asteroid can be captured ...
- 2,605
0
votes
0
answers
39
views
How do I convert from one local NED frame to another?
A little bit of background in case you are interested. I am running a re-entry simulation, and I am dealing with two different reference frames. The one with the higher fidelity dynamics is in the ...
- 1
2
votes
1
answer
96
views
How to plot a satellite's orbit around Earth in MATLAB?
Given orbit height, mass and initial velocity how should I plot a satellite's orbit in MATLAB? I was hoping to use verlet integration (I need to implement a solver) possibly the velocity-verlet. I ...
- 23
0
votes
0
answers
37
views
Alodine on Spacecraft External Surfaces?
What type of alodine is used for external coatings on satellites, if necessary? Is it type 1 (hex chromate) or type 2? Is there a disadvantage using type 1?
- 1
10
votes
6
answers
4k
views
How could 99942 Apophis, in 2029, be captured and brought into a low Earth orbit?
I'm currently attempting to plan out a mission where, in 2029, during Apophis's close approach to Earth, a rocket is sent up to intercept Apophis and decelerate it, making it orbit the Earth. At it's ...
- 111
5
votes
2
answers
1k
views
Are nozzle plugs taken out before launch or are they ejected upon ignition?
Inspired by this question. For most orbital launch vehicles, do their engines have nozzle plugs installed and what happen to them at launch? Are they manually removed during the prelaunch/rollout or ...
- 2,174
7
votes
2
answers
300
views
Helium balloon as a rocket
This question is not about rockoons, which are rockets using balloons as launch platforms to start from a greater altitude. This question asks about using the balloon itself as the rocket, like a toy ...
- 1,612
2
votes
0
answers
60
views
After one year exploring Jezero's crater floor, (why) hasn't there been any investigation into the presence of all the trace elements with PIXL?
PIXL instrument chart sample Credit:NASA/JPL-CALTECH
Of course PIXL has been used already in Jezero crater, but as far as I know only to identify mineral compositions and textures, as described in ...
- 7,052
4
votes
1
answer
67
views
Low-thrust maneuver validation in GMAT
I'm working on a LEO-to-LEO transfer with low-thrust propulsion. I've generated a control sequence with a direct optimization implemented by me and I would like to use GMAT to validate the maneuver.
I ...
- 41
6
votes
3
answers
110
views
Is crater counting accurate for relative dating between celestial bodies?
This Planetary Society article explains how crater density per unit area on the lunar surface helps identify what regions are older/younger than others. It also mentions that this chronology can be ...
- 445
4
votes
0
answers
44
views
Is there a significant reason why pintle injectors are only used in single configuration?
All of the resources I've managed to track down thus far about pintle injectors concern engines which only use a single, large central pintle for the entirety (or vast majority) of propellant supply ...
- 493
3
votes
1
answer
418
views
What's this inside the RD-0120?
There is a decent shot of the RD-0120's inside in this video:
I guess it's something covering the injector plate or even the combustion chamber since the SSME's injector looks very differently:
Also,...
- 5,351
5
votes
1
answer
332
views
How to find the hyperbolic angle given the mean anomaly?
I'm modelling a hyperbolic gravity assist trajectory around Jupiter and trying to calculate the coordinates for each hour interval before/after passing periapsis.
I've calculated $M_h = 0.0176$ is the ...
- 53
2
votes
0
answers
55
views
Which is the primary spacecraft in a conjunction?
I ask the question in the title because I cannot find a clear answer.
It seems that in collision avoidance, the primary spacecraft is always more accurately known then the secondary. But I think this ...
3
votes
0
answers
153
views
Why "quiet cruise" of a spacecraft would cost NASA 30 mln $ a year?
The 2022 Planetary Decadal Survey (Chapter 22) states that "quiet cruise" phase of an interplanetary spacecraft will cost about 30 million dollars a year for NASA. "Quiet cruise" ...
- 8,436
7
votes
3
answers
245
views
Can something like SpinLaunch actually work?
Can something like SpinLaunch actually work?
It appears that Spinlaunch attempts to accelerate a capsule to very high speeds and then basically throw it into space.
A regular rocket is moving slowest ...
- 395
5
votes
2
answers
286
views
Where can I find an up-to-date report on the Hubble Telescope's orbital history and current altitude?
I haven't been able to find a current report on the state of Hubble's orbital decay and I'm hoping someone can direct me to that info. The satellite tracker sites just present an average or estimate ...
- 51
0
votes
2
answers
148
views
Can a human base jump to earth from a satellite? [duplicate]
Only Felix Baumgartner managed to parachute from a helium balloon in the stratosphere is about as close as it gets.
But is it technically possible to do so from an orbiting satellite? Advantages is ...
- 425
11
votes
1
answer
1k
views
Does the Merlin vacuum engine on SpaceX's Falcon 9 gimbal?
SpaceX uses the Merlin Vacuum engine on the second stage of the Falcon 9 launch vehicle. Does the merlin vacuum engine gimbal or does the second stage uses only nitrogen cold gas thrusters for ...
- 2,251
18
votes
5
answers
11k
views
Why doesn’t NASA build its rockets using graphene?
Graphene would be a great material to build a rocket out of. Graphene is extremely thin. One single atom thin layer of graphene can withstand 15 000 000 pascal . A square meter of this material only ...
- 270
7
votes
1
answer
307
views
How far is the solar system's center of mass from the sun? [duplicate]
We often say that the planets orbit the sun. But, in reality, they orbit the solar system's collective center of mass. How far is that point from the center of the sun?
2
votes
1
answer
70
views
How does one calculate the look angle for non-geo satellites (i.e. LEO, HEO, etc.)
I'm trying to find a way to calculate look angles to not just GEO satellites, but LEO, MEO, and HEO sats. The only calculator I've found myself is here, which was referenced for a similar problem on ...
- 61
6
votes
1
answer
162
views
Can we use magnets to land a spaceship (Starship)?
Can we use magnets to land a spaceship (Starship)?
We could give the landing legs a magnetic flat surface or something and then the controller can reduce the magnetic strength or in other words, ...
4
votes
0
answers
105
views
Was Apollo 8 lunar orbit entry speed intentional at 7,777 ft/s?
When Apollo 8 first went behind the back side of the Moon, it was traveling at 7,777 feet per second (https://history.nasa.gov/afj/ap08fj/12day3_lunar_encounter.html). Was the speed being all 7s (the ...
- 41
0
votes
1
answer
123
views
Could we launch from the moon to another planetary body? [closed]
Would it be possible with currently rocket technology or technology towards the end of its development (ex. SLS, Starship, New Glenn, etc.) to launch from the moon. Of course, we would send down a ...
0
votes
0
answers
95
views
What artificial satellite has the closest stable orbit around the Earth? [closed]
What is the closest Earth orbiting satellite?
What is it's speed
What is it's purpose?
What is it's altitude?
0
votes
1
answer
198
views
Can we launch from the moon?
Would it be possible with currently rocket technology or technology towards the end of its development (ex. SLS, Starship, New Glenn, etc.) to launch from the moon. Of course, we would send down a ...
1
vote
0
answers
62
views
Why is most of mission control in Houston? [duplicate]
They were already making a mission control at Cape Canaveral, and then decided to move some, but not all, of it to Houston. Why? Wouldn't it make more sense to have the entire mission control in one ...
6
votes
1
answer
74
views
Apollo ALSEP RTG shorting switch to prevent overheat of the RTG?
I found these lines in the Apollo 14 Lunar Surface Journal:
116:07:37 Mitchell: Houston, the current reading is 8.
116:07:42 McCandless: Understand 8 amperes before pressing the
(shorting) switch.
...
- 46k
4
votes
1
answer
107
views
What was this stationary, then moving light point seen at daylight?
While lying on the garden couch looking straight up I noticed a point light directly above me, similar to a star. This surprised me as it was about an hour before sunset and the sky was still bright. ...
4
votes
0
answers
99
views
Can JWST come in for a pit stop? Is the fuel supply on JWST adequate for a transfer to an Earth Moon libration point to allow repairs?
The James Webb Space Telescope is generally considered unserviceable. This is primarily due to its location. Is it possible for the JWST to use a low energy heteroclinic transfer to reposition itself ...
- 6,410
8
votes
1
answer
740
views
What is the purpose of the shrouds surrounding these rocket engines?
While researching the purpose of some rocket engine components, I came across several images of perforated shrouds surrounding the combustion chambers of rocket engines.
I was highly curious about ...
- 103
3
votes
0
answers
60
views
short duration of crew 4 mission
I am wondering why the crew 4 mission is (for the moment) only planned for 4 and half months and not the usual 6-6.5 months? Thanks.
- 371
6
votes
0
answers
137
views
Will a watermelon decompose on the Moon?
If someone placed a watermelon or any other type of fruit on the Moon, will it decompose?
3
votes
1
answer
148
views
Where is the gas generator on the RS-68?
Wikipedia notes that the RS-68 uses a gas generator cycle. I've already seen a couple of photos of the RS-68 and I do not see any gas generator exhaust pipe or a pipe leading into the nozzle. So where ...
- 2,174
1
vote
1
answer
88
views
What is Rocket Lab Electron's dry mass?
Does anyone know how heavy Rocket Lab's Electron rocket is without fuel? Or do you by chance have any information about the fuel capacity of the first and second stage? I'm trying to model its flight ...
- 13
4
votes
1
answer
157
views
Do monopropellants have a characteristic length?
I was reading about calculating thrust chamber geometry, and a key tool seems to be the characteristic length, L*. The engine I'm modelling (hypothetically! please don't take down the question) uses ...
-3
votes
0
answers
101
views
Why doesn't New Shepard lift off at T=0 seconds? [duplicate]
I have seen New Shepard lift off at T+07 seconds and not at (or close to) T=00 seconds. Most of the rockets to the best of my knowledge lift-off exactly (or around) T=00 seconds. Engine ignition takes ...
3
votes
1
answer
83
views
Why did the "Running out of Toes" mission fail?
On May 15, 2021, Rocket Lab's Electron failed in the "Running Out of Toes" mission. The first stage had a nominal flight. Then, from looking at the launch video published by Rocket Lab, the ...
2
votes
1
answer
170
views
Why did the Hyperbola-1 launch fail in February 2021?
There is no launch video and very little data published about the launch. Considering how the maiden flight was successful, and it does appear that they made any design changes, what went wrong? Why ...
1
vote
1
answer
149
views
What is the point of having a central rocket engine when it receives performance losses?
Recently I asked this question about center engine performance and received an excellent answer from @OrganicMarble. The first sentence of the answer is
If anything, the flow field interactions hurt ...
- 2,174
7
votes
0
answers
88
views
What are the negatives associated with Thrust-augmented Nozzles aka Afterburning Rocket Engines?
An interesting comment here introduced me to the concept of Thrust-augmented Nozzles aka Afterburning Rocket Engines. The pubs I've read on it so far introduce the concept as a way to provide good ...
- 157k