# Why is this rocket transparent, and why is there a nozzle in the nose, pointing up?

This tough question links to the NASA YouTube video NASA 60th: How It All Began which shows a lot of really nice, historical file footage and stills.

At about 01:56 there is a still of an engineer standing next to what looks like a sounding rocket, or a model of one, that is transparent. Behind the engineer is an inflatable, metallized balloon, smaller, but similar to the ones shown in the question Did Echo 2 remain spherical without requiring gas pressure? If so, how is this known to be true?, and it looks like an un-inflated balloon is stowed in a compartment of the transparent rocket as well.

Most likely, the rocket is transparent because it is just a model, but I am still wondering what that thing is that looks like a nozzle, pointing up, in the cone.

below: Screen shot from the NASA YouTube video NASA 60th: How It All Began.

Click for full size.

• The outside shape of that model looks like Explorer 1 but the contents don't match that satellite. They don't match Echo 1 either. – Hobbes Jul 30 '18 at 10:49

That is a model of a Vanguard nosecone / third stage with an "IGY magnetometer satellite" at the top. The sphere is the "Sub-Satellite", a precursor of Project Echo.

Sad ending: It blew up in the launch attempt of the Vanguard SLV-5 vehicle.

Another picture of the model is found in the same document (source linked below).

Source

The official NASA history of Project Vanguard also calls it a "magnetometer". (page 226)

The final, real-world payload may not have looked like this model. It may have looked more like Vanguard 3 shown in the answer to this question: This BBC photo does not show a replica of Vanguard-1, what might it be?

• Thanks, I will dig into this after coffee. I'm guessing IGY is International Geophysical Year where nailing the Earth's oblateness through orbital tracking was one of the major goals, and the Fischer Ellipsoid of 1960 was a result, but I'll start to read up on the importance of magnetometers as well. To double check, this i.stack.imgur.com/pKSwx.jpg is an "IGY magnetometer satellite"? – uhoh Jul 30 '18 at 23:29
• That's what the source document calls it, but I think it's an early design model. The flight models seem to be "spheres with a cylinder attached" like Vanguard 3. I notice quite a few subtle differences between the model in the question and the one in the answer. – Organic Marble Jul 30 '18 at 23:35