Getting to space without rockets

In summary, there are many ways to increase the velocity of a spacecraft to overcome Earth's gravitational field and reach orbit, but the most practical seems to be using a balloon to achieve altitude and then using a spacecraft to pick up the balloon at a high altitude.
  • #1
Mfo
2
0
Hi guys,
Wacky idea,
Could we use a combination of balloons and spacecraft to place objects into orbit?

A balloon could be used to attain altitude and reduce air resistance but the problem faced is that we need to reach a high velocity to escape the Earth's gravitational field. The problem is velocity, a source of velocity is needed to impart on our platform at a high altitude.
Could we use something from space to impart the velocity to our object?

Why can't we use the moons slingshot to impart a large increase in velocity on any spacecraft which can then be used to pick up our platform at a high altitude and give it the necessary escape velocity?

This piggy back craft could be re used and slingshot around the moon again to increase the velocity for another.

Is this a stupid idea?
 
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  • #2
The idea of lifting stuff into orbit has lots of appeal, but slingshotting a spacecraft down into the atmosphere to pick up an object seems impractical. The maximum altitude of balloons is about 20-25miles, still well within the atmosphere, so the pickup vehicle would be wrapped in plasma from air friction, which makes it tough for it to find the target or to steer to it. Even more difficult, an object coming back from the moon would be moving at about 25,000 mph at the time of encounter, which makes for a very jerky pickup.
There has been some conceptual designs involving tethers (think space elevator) that involve geostationary tethers that dangle down into the upper atmosphere. The idea is that a rocket payload can be attached as the rocket is reaching its peak altitude, when there is minimal relative motion between the payload and the tether.
It is energetically much cheaper to just reach an altitude than to also speed up to orbital velocity.
 
  • #4
There's work being done on an "Airship to Orbit" in Rancho Cordova, California by a group called JP Aerospace. They are planning on using a ion/hybrid rocket motor mashup to provide propulsion. If it works, it'd be a quantum leap in capability. MY only question is how they intend to run a hybrid motor at any power level for the 5 days they estimate it would take to make the orbital insertion. A small liquid fuel rocket? Sure, just use a highly reliable fuel pump and a large fuel supply. The hybrid motor's got me scratching my head over how they plan on getting the required endurance.

There's a LOT of ideas on how to make it to orbit without a rocket; it's just that the cost is usually higher than the cost of continuing the existing "legacy" technology of expendable launch vehicles. If someone can come up with a way to break that cycle, the aerospace industry will beat a highway to their door. :)
 
  • #5
Why your idea of balloons wouldn't work is because the physical property that makes a balloon go up in the air is density. So the density of the system you are trying to float up through the atmosphere must simply be lower than that of the atmosphere. It wouldn't work because the air density decreases with altitude. http://upload.wikimedia.org/wikiped...omparison_US_standard_atmosphere_1962.svg.png

and second because most probably a system that we are interested in putting in the atmosphere is surely denser.
Now what they do is heat the air inside the balloon to reach a lower density. but if we want to reach the stratosphere for example, the amount of heat you would have to add to the air control volume in your balloon wouldn't seem so efficient I suppose, in addition to having to find a material to withstand a high temperature.
 
  • #6
The JP Aerospace concept seems ambitious in the extreme, think of a vehicle bigger than the Disney Magic cruise ship, much much lighter than air and driven to hypersonic speed at 200-400,000 ft altitude. Truly a project to push the state of the art for materials and structures, not to mention propulsion. My guess is that that kind of material would make a conventional reusable single stage to orbit vehicle quite practical, bypassing the need for balloons.
 

1. How is it possible to reach space without using rockets?

There are a few methods for getting to space without rockets, including space elevators, electromagnetic catapults, and air launch systems.

2. What is a space elevator and how does it work?

A space elevator is a proposed method for reaching space by using a long cable anchored to the Earth's surface and extending into space. The cable is held in place by the Earth's gravity and can be used to transport people and cargo into space.

3. What is an electromagnetic catapult and how does it work?

An electromagnetic catapult, also known as a mass driver, is a method for launching objects into space using electromagnets. The object is accelerated along a track until it reaches escape velocity and is launched into space.

4. How does an air launch system work?

An air launch system involves launching a spacecraft from a high-altitude aircraft. The aircraft carries the spacecraft to a high altitude and then releases it, allowing the spacecraft to use its own rockets to reach space.

5. What are the potential benefits of using alternative methods for getting to space?

Using alternative methods for getting to space can greatly reduce the cost and environmental impact of space travel. It can also open up new possibilities for space exploration and commercial activities in space.

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