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  (Source: DARPA)
DARPA's goal is to cut costs and increase convenience

The Defense Advanced Research Projects Agency (DARPA) is looking to create an unmanned vehicle for satellite launches that is faster, cheaper and more convenient than existing systems.

To do this, DARPA has introduced the Experimental Spaceplane (XS-1) program, which encourages the development of a fully reusable unmanned vehicle that would launch satellites into space. It would look, act, and cost more like a traditional plane. 

Current satellite launch technologies can cost hundreds of millions of dollars per flight, and can only fly a few times per year. To top it off, they typically require years of advanced scheduling. 

“We want to build off of proven technologies to create a reliable, cost-effective space delivery system with one-day turnaround,” said Jess Sponable, DARPA program manager heading XS-1. “How it’s configured, how it gets up and how it gets back are pretty much all on the table—we’re looking for the most creative yet practical solutions possible.”

The idea behind XS-1 is to have a vehicle that can operate from a clean pad, use only a small ground crew, and eliminate the need for costly specialized infrastructure.

Also ideal for XS-1 is a reusable first stage that would achieve hypersonic speeds at a suborbital altitude, and at that point, one or more expendable upper stages would detach and deploy a satellite into Low Earth Orbit. The reusable hypersonic aircraft would then make its way back to earth and be prepared for the next flight. 

The rapid turnaround between flights could be done through modular components, durable thermal protection systems and automatic launch/flight/recovery systems.

DARPA's goal is to develop a vehicle capable of flying 10 times in 10 days; reaching speeds of Mach 10+ at least once; launching a representative payload to orbit, and reducing the costs for small payloads by at least a factor of 10 to less than $5 million per flight.

Think you have what it takes to create what DARPA is looking for? The agency is holding an XS-1 Proposers’ Day on Monday, October 7, 2013. You must register to enter, and registration closes October 1. 

Source: DARPA



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RE: In other words
By 91TTZ on 9/18/2013 11:48:31 PM , Rating: 2
quote:
Then the Soviets launched Sputnik. We needed to put something into space too ASAP, the cost didn't matter. This eventually led to huge amounts of research dollars and time being invested in an ultimately inefficient method of putting things into space.


Actually a staged disposable rocket is the most efficient system that we have.

While the idea of a reusable spaceplane sounds great on paper it doesn't work well in reality. While you do get to reuse the spaceplane, you end up burning more aluminum and plastic in the form of solid rocket propellant than you get to bring back in the form of the spaceplane. It was also more expensive per launch than disposable rockets.

Long story short, you end up using more material and money trying to make your rocket system reusable.


RE: In other words
By Paj on 9/19/2013 8:15:54 AM , Rating: 2
Not necessarily. The main issue with multi-stage rockets is the weight of all the propellant you have to carry around. Multi stage rockets get around this by jettisoning weight as they rise higher.

The use of a combined air breathing jet/rocket engine is one avenue that is being explored. Take a look at the Skylon - its pretty amazing tech:

http://www.bbc.co.uk/news/science-environment-2333...

The key thing here is that it extracts the oxygen directly from the atmosphere, and cools the incoming air (which gets extremely hot travelling at hypersonic speeds)so it can be used to the engine. It then switches to a rocket-like mode to achieve escape velocity.


RE: In other words
By 91TTZ on 9/19/2013 2:13:03 PM , Rating: 2
While that definitely looks cool, I remember reading an article a while back that explains why air-breathing rockets or spaceplanes don't make sense. They said that the Space Shuttle was almost completely out of the atmosphere within 2 minutes, at which time it discards its solid rocket boosters. The rest of the time is spent accelerating so that it can gain enough velocity to achieve orbit.

A spaceplane would have to gain much of that speed within the atmosphere which presents other challenges. For one, it needs enough atmosphere to give the engine enough oxygen to work, but that atmosphere creates drag which reduces efficiency. Also, that drag creates heat so it limits the speed the aircraft can go without burning up. The Space Shuttle has to come in at a pretty shallow angle when it reenters the atmosphere so it can bleed off speed before it hits the denser air. Otherwise it would burn up.

If the team you linked to can find a way around these obstacles that would be awesome, since the spacecraft would be cheaper and more efficient.


RE: In other words
By JediJeb on 9/20/2013 6:07:57 PM , Rating: 2
quote:
The Space Shuttle has to come in at a pretty shallow angle when it reenters the atmosphere so it can bleed off speed before it hits the denser air. Otherwise it would burn up.


If the Shuttle had been designed to carry enough propellant to decelerate longer it could have gotten around the need for such a massive heat shield. If you can fire a rocket to decelerate to less than 5000mph before hitting atmosphere there would be far less heat generated upon reentry. The Shuttle used the cheap more efficient method of letting the atmospheric drag slow it down, but also needed to be protected from the heat that method generated. It only had to decelerate below orbital velocity and let gravity and friction do the rest.


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