Launching a Sounding Rocket Payload

or
How to Spend $2,000,000 in Half an Hour

The Payload

Before the thought of lighting up a surplus defense rocket becomes reality, you've gotta have something that can not only stand the nine g's of lift-off, but might be more interesting than shooting up, say, a Kodak Instamatic. Therefore, let me describe some of the finer points of the payload we had.

Because our payload needs to be pointed to the sun, these two sensors: the Lockheed Intermediate Sun Sensor (LISS-left) and the Mean Acquisition Sun Sensor (MASS-right) find the brightest source of light and tell the Reaction Control System which way to squirt a short burst of gas such that the payload can find the sun. The MASS points to within 30 degrees wherease the LISS locks on and holds to within a tenth of an arc-second.

You may have noticed that there were many more holes in the Front Aperature Plate that didn't have any visible telescopes. Well, here are the remaining eleven Herschellian telescopes sitting in the rear of the payload. These are single-mirror parabolas which focus the light which falls on them to cameras in the middle of the payload. If you look carefully, you'll see an empty ring. There used to be a mirror there, but it was jarred out of it's retaining ring upon our soft "landing." Behind these mirrors sit all the electronics which communicate to the transceiver and control the on-board cameras. You can also see the tail end of the 155.0nm Ritchey-Chretien.

The Rest of the Payload

Up until now, I've only been showing you the telescope section, but there is much more needed to make the experiment sucessful.

This shows our entire payload hanging on the rail. From front to back we have:

The Nose Cone
Besides providing some better aerodynamics than the grille on my 1984 Olds, inside is a magnetometer which keeps track of the Earth's magnetic field and is yet another way to maintain accurate pointing. The nose cone is lost as soon as the magnetometer is needed. The magnetometer is lost upon re-entry.
The Ogive Recovery System (ORSA)
Immediately past that first seam is where the parachute is located. 'Nuff said.
The Spacecraft Pointing and Reaction Control System (SPARCS)
The next set of gold and silver bands houses the pneumatics required to point the payload. There are 8 nozzles (x and y, roll and yaw) as well as four "eyes". These "eyes" (one of which is covered by a grey pad) are for coarse pointing to the sun-- even before the MASS kicks in.
The S-19
The brown cylinder behind the SPARCS houses a gyroscope for pointing accuracy during launch (it can also be used during flight). At this moment in time, the four canard wings (attatched where the pieces of yellow tape are) are not yet put on the payload. These wings gimbal at the command of the S-19 and are used for pointing during ascent.
The Transceiver
The section which grows a bit going aft houses the electronics and antennae for communication.
Our Payload
Housed inside the wide section are our telescopes, cameras, LISS and MASS, and support electronics. By the way, the telescopes are pointed back towards the rocket engines. This makes sense once you realize that you cannot see through the Transceiver, S-19, SPARCS, ORSA and magnetometer too well....

The High Velocity Separation System

Looking back to the front of the payload, we can now see the High Velocity Separation Section (HVSS) as it tapers down and connects to the motor itself. The HVSS separates from the payload by having two explosive bolts release the collar which holds them together. Inside the HVSS are three VERY POWERFUL springs which then push the payload and motor apart. (Gee, doesn't Dennis look bored?)

The Rocket Motors

If you look carefully at the picture above, you'll see a bump on an otherwise smooth, black motor. That rectangular bump is a shaped charge. There is another on on the other side. If the control of the rocket is lost, or if a serious malfunction occurs, the charges are set off. This blows holes in the top of the motor, allowing exhaust gasses to escape out of the top of the motor as well as the bottom-- thus there is no net thrust left and the rocket begins falling back to Earth. Hopefully the ORSA will have time to deploy....

Here we see both the Black Brandt IX "sustainer" (black) rocket and the Terrier "booster" (white). Look closely, and you can see the pentagram of ignition wire which ignites the booster. The booster stage only lasts four seconds. The sustainer only requires another minute to get the payload up to 230km. Separating the booster from the sustainer during flight is an interesting process. First of all, the booster is not securely attatched to the sustainer. They are not bolted or strapped or glued together. The Black Brandt simply sits atop the booster and the force of the booster holds them together during the four second flight. If you look between the two motors, you see the yellow air brake fins. When the booster cuts off, air friction alone pushes the booster away from the sustainer.

The fins on the Black Brandt are skewed slightly so that the entire rocket begins to spin like a bullet out of the barrel of a gun. When the Black Brandt cuts off, the payload is spinning at four rounds per second. Needless to say, this makes taking data difficult. However, just before the HVSS pushes the dead motor away from the payload, the Yo-Yo Despin section releases two lead weights on cords wrapped around the HVSS and, just like a spinning skater letting out his arms, as the cords unwind, the rocket slows down its spin rate. SPARCS finishes the job and stops the rockets spinning completely.

Well, now that you know how to get your rocket off the ground, there's just one last thing to do before launch....

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