Smallest rocket ever to carry satellite into orbit

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Winston

Lorenzo von Matterhorn
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Japanese sounding rocket claims record-breaking orbital launch - smallest rocket ever to carry satellite into orbit

https://www.nasaspaceflight.com/2018/02/japanese-rocket-record-borbital-launch/

All three stages of the SS-520 vehicle burn solid propellant. The first stage, the S-520, carries 1,587 kilograms (3,499 lb) of propellant, the second stage carries 325 kg (717 lb) and the third stage 78 kg (172 lb). The overall vehicle is 9.54 meters (31.3 feet) long, with a diameter of 52 centimeters (1.71 feet) and a total mass of about 2,600 kilograms (5,700 lb) at launch.

When it launched on Saturday, the SS-520 was expected to take less than four and a half minutes to reach orbit, with spacecraft separation timed for seven and a half minutes after liftoff. The rocket is spin-stabilized; as it ascends through the atmosphere fins at the base of the first stage impart a rolling motion which helps it to stay pointing in the correct direction.

The first stage burned for 31.7 seconds, during which time the vehicle reached an altitude of 26 kilometers (16 miles, 14 nautical miles) and a velocity of 2.0 kilometers per second (1.2 miles per second). After burnout the rocket coasted towards the apogee of its trajectory, shedding its nose cone 67 seconds into flight and the spent first stage one second later.

The interstage between the first and second stages houses rhumb line thrusters, which fire pulses timed to re-orient the rocket while it is still spinning. The thrusters began pulsing two and a half seconds after stage separation, and fire over a period of 47.1 seconds. Two minutes and 27 seconds into the flight – about half a minute after the thrusters have finished firing – the interstage will have jettisoned.

Two minutes and 37 seconds after liftoff, a check of the vehicle’s status will have been conducted. This serves two purposes: to ensure that the rocket is in good health and able to continue to orbit, and to determine the optimal time for second stage ignition. If the mission was continuing to plan, a command to enable second stage ignition and a revised ignition time will have been transmitted to the vehicle seven seconds later. Should it have been necessary to terminate the launch this command will not have been sent to the rocket, which prevents the second stage from igniting and the rocket would then fall into the drop zone that had been reserved for the first stage.

The exact timing of second stage ignition depends on the vehicle’s trajectory when the status check is undertaken, however the burn would have begun at around the three-minute mark in the flight and lasted for 24.4 seconds. After the burn ended, the second stage will have remained attached for about 30 seconds before it separated, with third stage ignition taking place three seconds after separation. The third stage burn is for 25.6 seconds, injecting itself and TRICOM-1R into orbit.

The SS-520 was expected to reach an orbit of approximately 180 by 1,500 kilometers (112 by 932 miles, 97 by 810 nautical miles), with inclination of 31 degrees. TRICOM-1R was to separate from the SS-520’s third stage seven minutes and thirty seconds after liftoff. Unusually for a CubeSat, TRICOM-1R does not use a deployment pod and separates directly from the rocket’s upper stage.

TRICOM-1R carries a store-and-forward communications payload and five small cameras that will return images of the Earth. The satellite was built by the University of Tokyo and was designed around the three-unit (3U) CubeSat form factor, although it is slightly larger than a standard 3U satellite due to its deployment mechanism and communications antennae. The satellite measures 11.1 by 11.1 by 34.6 centimeters (4.6 x 4.6 x 13.6 inches), including its antennae.


2018-02-03-022412.jpg


S-310/S-520/SS-520 (Sounding Rockets)

https://global.jaxa.jp/projects/rockets/s_rockets/

Japanese_sounding_rockets_shapes-01.jpg


TRICOM-1R

https://en.wikipedia.org/wiki/TRICOM-1R

[video=youtube;OeW-Qqu9-8U]https://www.youtube.com/watch?v=OeW-Qqu9-8U[/video]
 
Just curious about the following...

The rocket is spin-stabilized; as it ascends through the atmosphere fins at the base of the first stage impart a rolling motion which helps it to stay pointing in the correct direction.

The interstage between the first and second stages houses rhumb line thrusters, which fire pulses timed to re-orient the rocket while it is still spinning.

Just to make sure I understand - the rocket is rotating along its long axis (direction of flight). Thrusters orthoganal (at a right angle) to the axis of rotation are fired to adjust orbital trajectory. In theory, since the rocket is rotating, only one thruster would actually be needed.
 
[video=youtube;jBUFNgLrykc]https://www.youtube.com/watch?v=jBUFNgLrykc[/video]
 
Just to make sure I understand - the rocket is rotating along its long axis (direction of flight). Thrusters orthoganal (at a right angle) to the axis of rotation are fired to adjust orbital trajectory. In theory, since the rocket is rotating, only one thruster would actually be needed.

If the thruster were directly in line with the CG (across the airframe from it) this statement would be true. Unfortunately the CG moves as the fuel burns so having a single thruster as a concept is good, but they would need at least two to keep the forces from causing coning on the airframe. The required control loop would be quite wicked too.

The spin stabilisation only works for a certain amount of time. The spin eventually degenerates to an end-over-end tumble, as the most stable rotation axis is the one with the highest moment of inertia. I don't have a feel for how long this would take to occur.
 
If the thruster were directly in line with the CG (across the airframe from it) this statement would be true. Unfortunately the CG moves as the fuel burns so having a single thruster as a concept is good, but they would need at least two to keep the forces from causing coning on the airframe. The required control loop would be quite wicked too.

The spin stabilisation only works for a certain amount of time. The spin eventually degenerates to an end-over-end tumble, as the most stable rotation axis is the one with the highest moment of inertia. I don't have a feel for how long this would take to occur.

Even if level with the Cg, a single spin inducing thruster would result in some translation. Firing two simultaneously eliminates that.


Steve Shannon
 
Reading this page more closely, it seems to be saying the spin stabilization on the upper stages was inherited from the fin-induced spin of the first stage:

https://spaceflight101.com/japan-ss-520-5-launch-success/

It seems to be saying thrusters on the second stage were only for doing the pitch over and for attitude correction for the desired orbit. If that is so, then for a first, basic level flight where we just want to get to orbit, we could have the spin stabilization on the upper stages be induced by the first stage fins. For the pitch over, this might be accomplished by just giving the second stage a spring-loaded push on just one edge at stage separation.

Bob Clark
 
Who's "we"?

If you're talking about your idea to launch cubesats with O8000s, there are a few gaps in your logic. If you want help I can point them out for you.
 
Who's "we"?

If you're talking about your idea to launch cubesats with O8000s, there are a few gaps in your logic. If you want help I can point them out for you.

I’m always interested in further discussion of the topic. Looking at the delta-v’s, amateur or student teams can produce a rocket with the necessary delta-v to orbit by using staging, carbon composite casings, and vacuum optimized nozzles for the upper stages. The only thing needed is to give the upper stages spin or active stabilization under the high altitude, near vacuum conditions where fins are ineffective.

That article on the SS-520 appears to be saying the needed stabilization for the upper stages can be induced by the spin arising from the fins on the first stage.

Bob Clark
 
I’m always interested in further discussion of the topic. Looking at the delta-v’s, amateur or student teams can produce a rocket with the necessary delta-v to orbit by using staging, carbon composite casings, and vacuum optimized nozzles for the upper stages. The only thing needed is to give the upper stages spin or active stabilization under the high altitude, near vacuum conditions where fins are ineffective.

That article on the SS-520 appears to be saying the needed stabilization for the upper stages can be induced by the spin arising from the fins on the first stage.

Bob Clark

My first question is why you guessed 260 s for Isp. CTI in fact publishes Isp numbers for all of its motors, and they only claim 220 s:
https://pro38.com/products/pro150/motor/MotorData.php?prodid=40960O8000-P

If those of you interested in having on-topic discussions want us to continue this chat via PM, I'm happy to.
 
I’m always interested in further discussion of the topic. Looking at the delta-v’s, amateur or student teams can produce a rocket with the necessary delta-v to orbit by using staging, carbon composite casings, and vacuum optimized nozzles for the upper stages. The only thing needed is to give the upper stages spin or active stabilization under the high altitude, near vacuum conditions where fins are ineffective.

That article on the SS-520 appears to be saying the needed stabilization for the upper stages can be induced by the spin arising from the fins on the first stage.

Bob Clark
I'm going to be real honest for a sec: everyone on AR and TRF has been telling you you're missing huge pieces for the better part of 6mos.

Unless you have some startling new revelation, could you please slow down beating this drum? Show some actual work instead of just hijacking every tangentially related thread.

Regards,
-dh.
 
I'm going to be real honest for a sec: everyone on AR and TRF has been telling you you're missing huge pieces for the better part of 6mos.

Unless you have some startling new revelation, could you please slow down beating this drum? Show some actual work instead of just hijacking every tangentially related thread.

Regards,
-dh.

You have to crawl before you walk, and walk before you run. The amateur and student teams have to do a flight to ca. 100k feet before they do a suborbital flight, and do a suborbital flight, before they do an orbital flight. The USC rocket propulsion lab already succeeded in doing a flight to 100k feet last year. They now plan to do a flight to suborbital space next month:

https://www.uscrpl.com/traveler-iii/

If they succeed, other university teams can emulate their methods to also make a suborbital flight.
Understandable then for the university teams once they succeed with the flight to suborbital space to want to aim higher to orbital space.
A simple delta-v calculation shows it should be possible. But there’s a load of numerical simulation, practical design, and ground testing that needs to be done before the theory can be put in practice.

Bob Clark
 
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