Flight Question getting into orbit?

[Urwumpe]

cause if it said miles per hour for speed and feet then id know what my altitude should be. the real nasa dose not use kilometers they use feet and miles per hour.

Real NASA also uses meters, kilometers and meters per second since almost three decades. Only the manned spaceflight part of NASA is still unable to use it because of "contractors not being able to follow the new standards". It is a poor excuse, but it exists.

All unmanned NASA projects are actually using metric system since the early 1990s, cooperations with ESA had both metric and customary units since the 1970s.

ESA uses ONLY the SI system, JAXA AFAIR as well. The BBC Spaceflight journalism group uses Furlongs, supertankers and McLaren Sportscars or EE Lightnings as units.

---------- Post added at 03:31 PM ---------- Previous post was at 03:30 PM ----------

so what i should do is use the deltaglider and practice practice practice till i get it right of getting in and out of orbit then move on?

Until you reached enlightenment, yes. If you can predict correctly what will happen, and if TransX or IMFD are no problem for you, you can try more.

 

[Spacethingy]

so what i should do is use the deltaglider and practice practice practice till i get it right of getting in and out of orbit then move on?

Pretty much so.

Try Dan Steph's Delta Glider IV addon. It's got a fully automated ascend-to-orbit autopilot that's a bit of a cheat, but is dead useful for working out how exactly you do get into orbit.

The Orbiter manual's got some good rules/procedures too.

 

[rocketdued]

ok i'll give the delta glider a try.

 

[garyw]

The BBC Spaceflight journalism group uses Furlongs, supertankers and McLaren Sportscars or EE Lightnings as units.

As well as whales and double-decker buses. Fuel is measured in olympic sized swiming pools.

Rocketdued, You can use Orbiter in anyway you like but you'll find it a lot easier if you start out with the DG, learn the basics, especially learn what the Orbit MFD says and take it from here.

Personally, I write my own mission checklists as this helps me plan a mission and work out what I need to do as each stage. It also helps me to make sure that the vehicle is doing what it's supposed to be doing and I don't end up docking with the nose cone closed!

 

[jedidia]

Try Dan Steph's Delta Glider IV addon.

actually, I found the standard DG the optimal beginners craft: plenty of power (i.e. plenty of forgivness), unbreakable, works without checklists, and most important, does NOT have autopilots. Which I think is essential for a beginner to really figure out stuff (and it isn't that hard if you do your reading. I remember achieving orbit on 3rd attempt following a step-by-step tutorial, and then having another two fails trying without tutorial, until I really got the hang of it).

Go play in space is great to get a feel for the mechanics too. All in all, it's 50% reading and 50% try and error that makes your orbital mechanics 101.

 

[rocketdued]

oh ok. i seen that thing. i'll give the one a try. i had it once befor but i lost it in computer world:lol:

 

[Urwumpe]

Another note: For civil aircraft simulations feet and knots make sense, because the maximum altitude you can fly to legally is 69,000 ft. More is not displayed properly by pressure altimeters. It is a grown system (The USSR used kilometers and km/h), but it works.

In spaceflight, the fun begins at 340,000 ft. or 340 kft. Geostationary orbit is in 42164 km distance to the center of Earth. Or 26353 US miles. Or 22559.7 nautical miles. It doesn't really matter. Using kilometers just makes more sense in the big picture: Most important constants and physical models use SI units. if you would want to convert a non-spherical gravity model from SI units to US customary models, things will explode in mathematics.

So...what you want is basically just converting something, that operates in SI units under the hood, to US customary units, because of a strange preference, since you sure as hell can't imagine 26353 miles better than 42164 km. It makes no sense.

Also converting from miles per hour to feet per second is a major pain in the thrust section, which even NASA does not do in actual operations. In SI units, you can quickly go from kilometers per second to meters per second by just multiplying with 1000. kilometers per hour are not used in spaceflight, since it is a completely useless figure that only popular science writers need.

 

[rocketdued]

oh ok.

 

[Rtyh-12]

The main point of getting in orbit is getting enough altitude to get outside the atmosphere and enough horizontal speed to "fall around" the Earth. An altitude of more than 200 km is usually enough. The speed is lower the higher you go but for low altitudes a speed of 7.800-7.500 km/s is OK for a round enough orbit. A good example is the International Space Station (ISS) which orbits at 350 km and 7.800 km/s IIRC. In a spaceship like the DeltaGlider you usually go high, and then level out when you get enough altitude. I usually go at about 50-70 degrees upward, I start to level out slowly at about 90 km up. Then I just keep on burnin' until my apoapsis (highest point of the orbit, ApA parameter in Orbit MFD) reaches 350 km, which is my target altitude. I'm almost done by that point, but my orbit still intersects the denser part of the atmosphere, and that means that I'll burn up. That's why, when I reach my apoapsis, I turn prograde (forward in orbit, Orbiter includes an autopilot that keeps prograde direction for you, see the buttons on the panel or the [ shortcut key on the keyboard) and just burn until my periapsis (lowest point of an orbit, PeA parameter in Orbit MFD) reaches 350 km (or whatever my target altitude is). After that, I am in orbit and I can relax a little...

Hope this clears up everything for you! Happy orbiting!

P.S.:If you don't see the PeA or ApA parameters, but instead see the PeD and ApD parameters, press the Dst button of the MFD. PeA/ApA shows the altitude, while PeD/ApD shows the distance from the planet center.

 

[Wishbone]

7800 km/s => 7800 m/s. At 7800 km/s one is feeling relativistic effects already...

 

[rocketdued]

ohok.

 

[Rtyh-12]

:facepalm:

Epic fail...sorry for any confusion...

 

[rocketdued]

:lol: who failed?

 

[Urwumpe]

If you are talking about GPS, you measure relativistic effects already at the 7 km/s at which the satellites travel... the clock drift by relativity means about 1 meter of inaccuracy in your position estimate.

But at 7800 km/s you could see Einstein wave at you.

 

[rocketdued]

:lol: ok. yeah i got the gps figured out so far

 

[Rtyh-12]

If you are talking about GPS, you measure relativistic effects already at the 7 km/s at which the satellites travel... the clock drift by relativity means about 1 meter of inaccuracy in your position estimate.

:nono:11 km/day:facts:

 

[Urwumpe]

:nono:11 km/day:facts:

11 km/day? what do you measure, teenage glaciers? :lol:

The error in pseudo-range is about 10 km/day, but not the error in the least-square position estimate from four or more pseudo-ranges - that is about one meter in the worst case.

 

[Sky Captain]

With default shuttle (scenario Atlantis sattellite launch) it is possible to achieve relatively stable ~160 x500 km orbit without even using the OMS and a little bit of fuel left in ET.

 

[Urwumpe]

With default shuttle (scenario Atlantis sattellite launch) it is possible to achieve relatively stable ~160 x500 km orbit without even using the OMS and a little bit of fuel left in ET.

If you throttle down soon enough, you should even get a slightly higher perigee, the only limiting factor is that you have to climb high enough until cutoff.

 

[Sky Captain]

Yeah, I give it another try and this time I reached 240x540 km orbit in single SSME burn with 38 tons of fuel left in ET. I guess the default shuttle is a bit overpowered.