From Earth to orbit using a single-stage rocket

[Cripplecreek]

New Mexico-based ARCA Space Corporation has announced that it is developing the world's first Single Stage to Orbit (SSTO) launch vehicle that can deliver both a small payload and itself into low Earth orbit, at a cost of about US$1 million per launch. Dubbed the Haas 2CA after the 16th century rocket pioneer Conrad Haas, the new booster uses a linear aerospike engine instead of conventional bell-shaped rocket engines to do away with multiple stages.

Getting into space is a very complicated affair. To put a payload, like a satellite, into orbit means shooting it out of the atmosphere at about 18,000 mph (29,000 km/h). This takes significant energy in the form of rocket propellant, which must be held inside a rocket and burned by the rocket engine. Unfortunately, that means adding more fuel to lift the rocket, its engine and the original fuel, then more fuel to lift all that, then more fuel to lift that fuel.

http://newatlas.com/single-stage-rocket/48710/



Mo pics

http://newatlas.com/single-stage-rocket/48710/#gallery

[geronl]

Seems like, at some point, it would be lifting a lot of dead weight

[Cripplecreek]

Seems like, at some point, it would be lifting a lot of dead weight

It appears to be a fairly small rocket for lifting small satellites.

[Joe Wooten]

I'll believe they have one when I see it put a satellite in orbit.

[r9etb]

Seems like, at some point, it would be lifting a lot of dead weight

It is.  That's the whole logic around staging.  Of the stack of rocket, fuel, and payload on the launch pad, over 90% of that goes into the rocket, and the great majority of that is fuel -- the payload is tiny  by comparison.  The more structure you have to drag along, the more fuel you have to launch with.  So you get rid of all the excess weight as soon as you can -- i.e., as soon as the first-stage tanks are empty.

The key to an SSTO mission is to create a system that is very light -- the structure, tanks, and engine don't impose too great a mass penalty.  You're still going to have to launch with a butt-load of fuel, though.

[catfish1957]

Question for any local astrophysicist here.  This has always made me wonder.

Even though the moon has 1/6 the gravity of earth, I still always wondered how the lunar lander was able to launch into orbit with what appears to be a relatively small source of thrust.  Lack of atmospheric drag? 

[r9etb]

Hmmmm.... I have to wonder about the following:

The principle behind the aerospike is that the air itself acts as the missing half of the rocket bell, containing the hot gases as they leave the combustion chamber. This means that as the rocket flies higher, the thinner air holds the gases less tightly and they spread out more as if the rocket bell has gradually grown larger.

Granted it's been a long time since I've had any courses on nozzle design, but this seems like the exact opposite of what you want.  The nozzle extensions on modern upper stages are designed to keep the exhaust contained and flowing in the right direction.

[Suppressed]

Question for any local astrophysicist here.  This has always made me wonder.

Even though the moon has 1/6 the gravity of earth, I still always wondered how the lunar lander was able to launch into orbit with what appears to be a relatively small source of thrust.  Lack of atmospheric drag?

I'm not an astrophysicist, but perhaps you'll indulge my atttempt at an answer.  I had the same question when I was a lad.

In addition to the atmospheric drag issue, and the difference in gravity, consider what was being lifted.  The Lunar Module Ascent Stage was tiny....only about 5 tons.  Compare that to the full Saturn V launching from earth, which was more than 3000 tons.  The Ascent engine (APS) was small but powerful for its size. 

(Admittedly, these numbers might be off some, and I don't have time to look stuff up right now...but the ballpark should be right.) 

[r9etb]

Question for any local astrophysicist here.  This has always made me wonder.

Even though the moon has 1/6 the gravity of earth, I still always wondered how the lunar lander was able to launch into orbit with what appears to be a relatively small source of thrust.  Lack of atmospheric drag?

In part, yes.  But also, orbital velocity around the moon is only about 1600 m/sec (at 200 km altitude).  By comparison, you need about 7800 m/sec to get into low Earth orbit.  So it's a lot less difficult on the moon.

It still required about 2400 kg of propellant in the LM ascent stage, but that's actually a pretty compact amount of mass.  It was a lot harder (took a lot more fuel) to do the whole "land on a tail of fire" thing.

[Cripplecreek]

I'm not an astrophysicist, but perhaps you'll indulge my atttempt at an answer.  I had the same question when I was a lad.

In addition to the atmospheric drag issue, and the difference in gravity, consider what was being lifted.  The Lunar Module Ascent Stage was tiny....only about 5 tons.  Compare that to the full Saturn V launching from earth, which was more than 3000 tons.  The Ascent engine (APS) was small but powerful for its size. 

(Admittedly, these numbers might be off some, and I don't have time to look stuff up right now...but the ballpark should be right.)

The low gravity vacuum environment sure makes the moon a great place to launch deep apace missions. Launching a Saturn V from the moon would mean some serious speed. (However you'll have to slow down to avoid overshooting your destination)

[r9etb]

The low gravity vacuum environment sure makes the moon a great place to launch deep apace missions. Launching a Saturn V from the moon would mean some serious speed. (However you'll have to slow down to avoid overshooting your destination)

Look up "patched conic" trajectory planning. 

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