#Did wallops rocket launch full#
#Did wallops rocket launch series#

Regardless of what we have said so far, an increase in payload capacity of one tonne from a base payload of around ten tonnes seems fairly useful. However, we do not observe any significant advantage from increasing the altitude of the launch site, which turns out to be negligible in effect. This means that we can observe the gains available by using a more efficient engine nozzle, which provides more delta V for the same amount of propellant, and the relative reduction in air resistance. Horizontal velocities of objects compared with LEO orbital velocity. In this example, the new, slightly-enlarged nozzle would achieve 380 seconds of specific impulse at the launch site and 420 s in vacuum, compared with 360 and 412 seconds respectively, obtained by the standard RS-68A engine on the real Delta IV Medium. This means that we could increase the size of our nozzle, which could in turn offer a few percent more efficiency on the rocket’s first stage. At this altitude, the atmosphere is already 40% less dense than it is at sea level. In this scenario, we choose to place a new launch pad at the top of Pikes Peak, because it is close to the workforce, it has a paved road all the way to the top of the mountain, and is fairly high up with a summit at 4,302 m (14,114 feet). Since we now have the Rocky Mountains in our “back yard”, why should we not choose a new launch site for the Delta IV Medium, with no solid rocket boosters? (Yes, we do know that this rocket is retired from flight, but it is a useful example for us to use.) To try to minimize the change for any existing launch provider, let us pretend that we are United Launch Alliance (ULA) from the United States, whose headquarters are in Colorado, not too far from Denver. Let us imagine for a moment that we do want to launch from the top of a mountain. Illustration of flow separation inside a rocket nozzle. This means that at sea level, where the pressure is nominally 1 bar (by definition), the exhaust is rarely below 0.4 bar at the exit of the nozzle, so that we can avoid flow separation. (Credit: Chris Carlson / Associated Press) Falcon 9 second stage with single vacuum-optimized Merlin engine (Credit: SpaceX)Īs a general rule of thumb, it is not a good idea to have the pressure at the exit of your nozzle be lower than about 40% of the pressure of the air surrounding you. Falcon 9 first stage with sea level Merlin engines

The videos show that it is almost as wide as the entire rocket. During stage separation, it is clear how wide that upper stage nozzle is.

This is able to fit 9 sea level engines on the first stage, but only one vacuum engine on the upper stage.

It is really clear to be able to see the difference between a sea level engine and a vacuum engine by looking at the 3.7 m diameter on the Falcon 9 rocket. This can cause flow separation at the exit of the nozzle, and that could damage the engine. Nozzle SizeĪ larger nozzle can lower the pressure of the exhaust below the ambient air pressure, especially if it is at sea level where the ambient air pressure is highest. Illustration of a vacuum-optimized engine and nozzle. This article is also available in the form of a video on our YouTube channel Everyday Astronaut. In the next video and article, we will discuss some other questions such as “why not use other technologies, such as jet engines, to help make rocket launch systems more efficient?”, or how about launching from aircraft, or using magnetic levitation systems to help “throw” rockets like a catapult.

#Did wallops rocket launch series#

Having said all of that, this is the first video and article in a short series of two. We will review the issues involved in launching from the tops of mountains, or from being close to the equator, and we will attempt to work out why we don’t tend to see this happening very often, if at all.īefore we dive in, however, we should recommend that you have already seen Everyday Astronaut’s video and article “The Difference Between Space And Orbit”, as these discuss where “space” starts, the Kármán line, apogee and perigee, and a few other terms that we might find helpful to understand. In this video and article, we will look at the physics of launching rockets from different locations on Earth.

#Did wallops rocket launch full#

Why are we not taking full advantage of the planet that we’re living on? It is offering us free energy, isn’t it? How much difference in performance is there in launching a rocket from different locations? In this article Flight profile of an equatorial launch to Low Earth Orbit (LEO).