3 ms·
It only takes 2 km/s to get to 100 km altitude on a ballistic hop. But the gravity pulls you down. It takes a 8 km/s horizontal velocity just to stay in orbit.
by Gravityloss 11y ago
It only takes 2 km/s to get to 100 km altitude on a ballistic hop. But the gravity pulls you down.
It takes a 8 km/s horizontal velocity just to stay in orbit. That is in addition to the 2 km/s to just get to the right altitude.
So just by speed ratios orbit is 5x the difficulty of a space hop. In reality rocket scaling is exponential (you need more fuel to carry more fuel...)
Anyway, I do think nowadays "amateurs" actually could build orbital rockets with budgets in the low millions class. Modern electronics and GPS make it a bit easier than a few decades ago.
- idlewords 11y agoGPS receivers have US-government mandated speed and altitude cutoffs to prevent this scenario. A nice writeup on bypassing them is here: http://www.wired.com/2013/09/bypassin-us-gps-limits-for-active-guided-rockets/ http://www.wired.com/2013/09/bypassin-us-gps-limits-for-acti...
- sbierwagen 11y agoUS-government mandated GPS receivers "capable of providing navigation information at speeds in excess of 600 m/s" are actually covered under the Missile Technology Control Regime. (category II 11.A.3.b.1) http://www.mtcr.info/english/MTCR-April2011-Technical-Annex.pdf http://www.mtcr.info/english/MTCR-April2011-Technical-Annex.... The MTCR has 34 members, basically the G20 minus China and India. Since the MTCR doesn't have any provisions for enforcement, (It's "an informal and voluntary partnership") its US equivalent is the International Traffic In Arms Regulations Act. (Category XV, Section c, if you want to read how the US statute words it. In imperial units, of course, just to make things simple.)
- rory096 11y agoHere's a great graphic on delta-v needed to get all over the solar system (including various orbits), by the way. https://i.imgur.com/SqdzxzF.png https://i.imgur.com/SqdzxzF.png
- rbanffy 11y agoIt's a toll map. :-)