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Re:USC Student Rocket Group Shatters International Amateur S... by Haugsevje on Tuesday December 03, 2024 @08:58AM (#42306050)
Are they as high up that it could start orbiting?
Re:USC Student Rocket Group Shatters International Amateur S... by nordsieck on Tuesday December 03, 2024 @09:01AM (#42306081)
> Are they as high up that it could start orbiting?

1. No

2. Orbit is more about speed than height. You have to get high enough that the atmosphere doesn't aggressively degrade your velocity, but the key is to hit ~8km/s, although that number changes depending on your altitude.

edit: 30km/s -> 8km/s

Re:USC Student Rocket Group Shatters International Amateur S... by zamadatix on Tuesday December 03, 2024 @09:19AM (#42306279)
30 km/s is ~the speed at which Earth orbits the Sun. For orbiting Earth you just need a mere <8 km/s.
Re:USC Student Rocket Group Shatters International Amateur S... by nordsieck on Tuesday December 03, 2024 @09:43AM (#42306585)
Thanks for the correction.
Re:USC Student Rocket Group Shatters International Amateur S... by phaedrus on Tuesday December 03, 2024 @09:00AM (#42306072)
Orbiting has more to do with velocity than altitude.
Re:USC Student Rocket Group Shatters International Amateur S... by jvanderbot on Tuesday December 03, 2024 @09:02AM (#42306088)
Specifically, you need to be moving approx 10 km/s which 22,000 mph or mach 30.
Re:USC Student Rocket Group Shatters International Amateur S... by laverya on Tuesday December 03, 2024 @06:25PM (#42312841)
You only need to be moving ~7.5-8km/s, but getting to orbit tends to take 9.5-10km/s of total delta-v due to needing to ascend, aerodynamic drag, and other losses.
Re:USC Student Rocket Group Shatters International Amateur S... by Haugsevje on Tuesday December 03, 2024 @09:04AM (#42306112)
Ahh yes, of course! I guess they are not high enough for geo stationary orbit?
Re:USC Student Rocket Group Shatters International Amateur S... by pavon on Tuesday December 03, 2024 @10:37AM (#42307269)
Even for geostationary you still need to gain a ton of horizontal velocity, more than LEO. You are staying over the same spot on the earth, but the earth is rotating and you need to match that same angular velocity. Being at a higher altitude you need a faster linear velocity to match that angular velocity, since you have a larger circle to travel in the same amount of time.
Re:USC Student Rocket Group Shatters International Amateur S... by marcyb5st on Tuesday December 03, 2024 @09:11AM (#42306186)
Geo stationary orbit is 36000 km give or take.

Orbiting however is more about radial velocity. You are sort of constantly falling towards Earth, but you are moving so fast that you always miss it and so you end up orbiting it. A great animation on the subject: https://www.reddit.com/r/Damnthatsinteresting/comments/1btbn...

Re:USC Student Rocket Group Shatters International Amateur S... by jadyoyster on Tuesday December 03, 2024 @09:10AM (#42306174)
Even if they were high enough they would just fall back to earth. There are lots of videos explaining orbit, this one looks good: https://www.youtube.com/watch?v=bcvnfQlz1x4
Re:USC Student Rocket Group Shatters International Amateur S... by Haugsevje on Tuesday December 03, 2024 @09:22AM (#42306306)
That's a very clarifying video! Suddenly i remembered my pre-college physics:)