Why cant the Falcon Heavy fly in a straight line to orbit?

[Jcc]

Isn't straight line orbit an oxymoron?

Yes. Yes it is.

[DecoLV]

OK, I'm going to slightly bend the trajectory of this thread by asking a related question of my own. Can you achieve orbit via direct rendevous?

Try this. The space shuttle is orbiting at 115 miles, payload bay toward Earth. Freedom 7 with Alan Shepard is launched at the perfect moment so that the peak of the capsule's path (115 miles) intersects with the shuttle. The Mercury capsule flies into the cargo bay where is it seized by [insert relevant technology here] and captured. Mercury Freedom 7 and Al Shepard are now in orbit. Without an Atlas.

Right?

[WmThomas]

The space shuttle in your example would be decelerated by the capsule. Whether the united vehicles would stay in orbit is an open question.

[AS-503]

OK, I'm going to slightly bend the trajectory of this thread by asking a related question of my own. Can you achieve orbit via direct rendevous?

Try this. The space shuttle is orbiting at 115 miles, payload bay toward Earth. Freedom 7 with Alan Shepard is launched at the perfect moment so that the peak of the capsule's path (115 miles) intersects with the shuttle. The Mercury capsule flies into the cargo bay where is it seized by [insert relevant technology here] and captured. Mercury Freedom 7 and Al Shepard are now in orbit. Without an Atlas.

Right?

Okay, I'll drive my pickup truck by you at 17,500 MPH and you just hop in when I drive by;)



 

Read this: https://what-if.xkcd.com/58/

[NovaSilisko]

OK, I'm going to slightly bend the trajectory of this thread by asking a related question of my own. Can you achieve orbit via direct rendevous?

Try this. The space shuttle is orbiting at 115 miles, payload bay toward Earth. Freedom 7 with Alan Shepard is launched at the perfect moment so that the peak of the capsule's path (115 miles) intersects with the shuttle. The Mercury capsule flies into the cargo bay where is it seized by [insert relevant technology here] and captured. Mercury Freedom 7 and Al Shepard are now in orbit. Without an Atlas.

Right?

The Shuttle impacts poor Freedom 7 and Al with a relative velocity comparable to the shuttle's orbital velocity. Both are blasted apart in an instant. A small meteor shower occurs slightly downrange of the cape as bits of Freedom 7 burn up in the atmosphere.

The cloud of debris in orbit from the Shuttle renders LEO unusable for some time.

Program subsequently cancelled due to being "a really terrible idea"







...however.

If you were to perhaps fire a grappling hook out of the payload bay in a retrograde direction, kept the cable unspooling at 8 km/s, latched the hook onto the Mercury capsule, and then slowly reversed the unspooling to winch it in, you could indeed drag the capsule to orbit, at the expense of some of the Shuttle's orbital velocity.

All the mass allocated to the gigantic hypervelocity winch system means however that the Shuttle couldn't carry any deorbit propellant, and the stack reenters on its own after a few weeks due to orbital decay.

This program was also cancelled.

^{(I wonder if this would work for slower speed flybys of asteroids for sample return? Fire a scooper on a long cable at the asteroid when flying past at something like 500 m/s, then unlatch it from the asteroid and yank the thing out before slowly winching it back in)}

[Lee Jay]

OK, I'm going to slightly bend the trajectory of this thread by asking a related question of my own. Can you achieve orbit via direct rendevous?

Try this. The space shuttle is orbiting at 115 miles, payload bay toward Earth. Freedom 7 with Alan Shepard is launched at the perfect moment so that the peak of the capsule's path (115 miles) intersects with the shuttle. The Mercury capsule flies into the cargo bay where is it seized by [insert relevant technology here] and captured. Mercury Freedom 7 and Al Shepard are now in orbit. Without an Atlas.

Right?

The Shuttle impacts poor Freedom 7 and Al with a relative velocity comparable to the shuttle's orbital velocity. Both are blasted apart in an instant. A small meteor shower occurs slightly downrange of the cape as bits of Freedom 7 burn up in the atmosphere.

The cloud of debris in orbit from the Shuttle renders LEO unusable for some time.

Program subsequently cancelled due to being "a really terrible idea"

If I understood the question asked, Freedom 7 would be orbital via direct insertion.  Assuming apogee is the same but perigee is lower, there would still be a relative velocity, but it would be no where near orbital velocity.

[NovaSilisko]

If I understood the question asked, Freedom 7 would be orbital via direct insertion.  Assuming apogee is the same but perigee is lower, there would still be a relative velocity, but it would be no where near orbital velocity.

Well, I was interpreting it as being launched by a Redstone rocket into a steep suborbital trajectory with the apogee at the Shuttle's orbital altitude, not unlike the actual Mercury suborbital flights. It would a bit less than orbital velocity though, unless you launched the capsule north or south.

[kch]

OK, I'm going to slightly bend the trajectory of this thread by asking a related question of my own. Can you achieve orbit via direct rendevous?

Try this. The space shuttle is orbiting at 115 miles, payload bay toward Earth. Freedom 7 with Alan Shepard is launched at the perfect moment so that the peak of the capsule's path (115 miles) intersects with the shuttle. The Mercury capsule flies into the cargo bay where is it seized by [insert relevant technology here] and captured. Mercury Freedom 7 and Al Shepard are now in orbit. Without an Atlas.

Right?

Okay, I'll drive my pickup truck by you at 17,500 MPH and you just hop in when I drive by;)



 

Read this: https://what-if.xkcd.com/58/

Yup.  Basically, [SPLAT] and resulting pieces-parts all over Hades ... nasty.  Wouldn't wish that on my worst enema. 

[Patchouli]

Oh and I recommend both Kerbal Space and Orbiter to any and all.

Kerbal is a wonderful simulator if you'd like a layman's model. Apart from the fact that very few of the physics are scaled accurately (the game is designed to be playable, after all), and appears to have a slightly differing comprehension of mass, relativity, the light barrier, conservation of momentum, newtonian principles, ecetera, it serves as a majestic introduction to the wonders of real-world spaceflight. Barring a few reasonable balance reductions (that can easily be modded back in), such as simplified aerodynamics, aerobreaking and… ah, none-incendary meteoric re-entries,

Orbiter is older than much of the ISS, a number of prominent STS missions and that SpaceX thing we all know and love, yet is still without equal. However, it only models Newtonian physics, and is heavily unpermissive of in game craft design, which is much of Kerbal's thrill.

(I personally advocate Kerbal).

I played with Orbiter before KSP.

Probably why I made it to orbit in KSP on my third try.

As for learning basic orbital mechanics I learn about them when I was 13 by reading books and watching educational programs.
I remember in science class being taught about Newton's cannon.

[puetzk]

If you were to perhaps fire a grappling hook out of the payload bay in a retrograde direction, kept the cable unspooling at 8 km/s, latched the hook onto the Mercury capsule, and then slowly reversed the unspooling to winch it in, you could indeed drag the capsule to orbit, at the expense of some of the Shuttle's orbital velocity.

All the mass allocated to the gigantic hypervelocity winch system means however that the Shuttle couldn't carry any deorbit propellant, and the stack reenters on its own after a few weeks due to orbital decay.

This program was also cancelled.

^{(I wonder if this would work for slower speed flybys of asteroids for sample return? Fire a scooper on a long cable at the asteroid when flying past at something like 500 m/s, then unlatch it from the asteroid and yank the thing out before slowly winching it back in)}

Designed in a slightly more workable fashion, this is known the Rotovator or momentum exchange tether

[GORDAP]

I guess there is one way that you could launch 'straight up' and achieve Earth orbit:  Launch from the equator on a trajectory that looks like straight up to an observer near by on the surface, and which tops out at exactly geosync height.

I think you'd have to accelerate eastward to make this happen, and it wouldn't be a particularly fuel efficient way to get to geosync orbit, but again I think it would look like a launch straight up to orbit, right?

[Nomadd]

 This can't be right. All you have to do to get from one place to another in space is look for where you want to go and scoot over in an MMU. I know because I saw it in Gravity.

[Dave G]

Isn't straight line orbit an oxymoron?

Yes. Yes it is.

According to Einstein, all orbits are straight lines, but gravity warps space-time to make them appear elliptical.

Of course, that's about as useful as anything else in this thread...

[matthewkantar]

 Straight up, bee line to a place near where the moon will be when you get there. slingshot around the moon so that you go near where the earth will be when you get there, aero braking, thrusters, blah blah, kabam,  earth orbit.

Worst thread ever maybe?

Matthew

[andrewsdanj]

I guess there is one way that you could launch 'straight up' and achieve Earth orbit:  Launch from the equator on a trajectory that looks like straight up to an observer near by on the surface, and which tops out at exactly geosync height.

I think you'd have to accelerate eastward to make this happen, and it wouldn't be a particularly fuel efficient way to get to geosync orbit, but again I think it would look like a launch straight up to orbit, right?

So...... a space elevator without the elevator? :-)

[DecoLV]

"Second star to the right, and straight on 'til morning."









Well, someone had to say it. 

[CuddlyRocket]

OK, this thread appears to have morphed into a general Q&A thread about orbits and there's a dedicated Q&A Section of the forum for that. Locked.