Princeton University attempt at a suborbital space shot?

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jsdemar said:
It will be interesting to learn what they used as a second-stage ignition system, and why it failed. Sustainer came back under 'chute, from what I can tell.
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Coleman is using a kevlar 12" drogue as the main, so with the additional mass of the propellant the sustainer would have come in a bit hotter than planned.

Hopefully it didn't find a rock on impact.
 
Figure out what went wrong, why it didn't light, fix it, and launch it again. They deserve to launch it again having made it this far. They will earn it and I am proud for all of them. They came too far to simply give up.
 
jsdemar said:
It will be interesting to learn what they used as a second-stage ignition system
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Lots of detail in their FAA document: "The sustainer motor is ignited with a Rocketflite LLC MagFire2 electric match, a vacuum-tested, fluoroelastomer-based initiator developed for the
United States Navy. The electric match is fed through the forward closure of the sustainer motor, and is augmented with a confined black powder charge to ignite the surface of the propellant
grain at high altitude." They had an angle lockout so it may have simply never tried to ignite.

https://rockets.princeton.edu/spaceshot-technical-documentation
 
mikec said:
Lots of detail in their FAA document: "The sustainer motor is ignited with a Rocketflite LLC MagFire2 electric match, a vacuum-tested, fluoroelastomer-based initiator developed for the
United States Navy. The electric match is fed through the forward closure of the sustainer motor, and is augmented with a confined black powder charge to ignite the surface of the propellant
grain at high altitude." They had an angle lockout so it may have simply never tried to ignite.

https://rockets.princeton.edu/spaceshot-technical-documentation
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Fluoroelastomer, Mg Tef, a quick flash.
Black powder augmented, worse thing they could have used.
Red propellant, why? Low ISP and hard to light.

M
 
MClark said:
Red propellant, why? Low ISP and hard to light.

M
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Might have been a acceleration limit on airframe or avionics that lead them to pick a lower performance propellant. They likely did not know it was harder to light. Maybe they got focused on altitude predictions? And I'm not making fun of them. It can be as simple as we didn't know X. There are so many little detail oriented experience based practical things to this hobby that it's impossible for engineering student teams to know everything HPR. So a lot of small mistakes compared to hobbyists are made. I've heard people cuss commercial e-matches and call name brand companies garbage. If the winds aloft moved the rocket off course and changed its angle of attack far enough it wouldn't light anyways. It could be winds aloft and stability related. Maybe the coding parameters for ignition were too strict. It is wonderful news that they simply got their sustainer back. Insufficient voltage or amperage for ignitor to ignite. It could literally be anything but a stubborn propellant won't help if the ignitor is burnt. Anyways I don't want to judge them or speculate too much. They can change a reload or e-match method if needed. They are busy now.
 
I read some of the description on above link.
Was the booster not recovered? Is so the "recycle" period will be vast if a spare was not made.
 
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jsdemar said:
Second hand info: booster underperformed and the pitch angle didn't qualify for upper stage ignition.
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I know Coleman and have first hand information that at least partially disputes the above. However I will let Coleman comment if and when he wants to.

Andrew_ASC said:
Might have been a acceleration limit on airframe or avionics that lead them to pick a lower performance propellant. They likely did not know it was harder to light. Maybe they got focused on altitude predictions? And I'm not making fun of them. It can be as simple as we didn't know X. There are so many little detail oriented experience based practical things to this hobby that it's impossible for engineering student teams to know everything HPR. So a lot of small mistakes compared to hobbyists are made. I've heard people cuss commercial e-matches and call name brand companies garbage. If the winds aloft moved the rocket off course and changed its angle of attack far enough it wouldn't light anyways. It could be winds aloft and stability related. Maybe the coding parameters for ignition were too strict. It is wonderful news that they simply got their sustainer back. Insufficient voltage or amperage for ignitor to ignite. It could literally be anything but a stubborn propellant won't help if the ignitor is burnt. Anyways I don't want to judge them or speculate too much. They can change a reload or e-match method if needed. They are busy now.
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Andrew, as someone who works with College or in my case University students I agree with your generalization about hobbyists vs. College students. However this is one case where at least one member of the Princeton team has an abundance of hobbyist experience as well as a strong track record to back it up. I am speaking of Coleman Merchant.

I consider Coleman a friend and have flown with him several times over the last 4 years and while he would be the first to say that he has much to learn, as we all do, I would not characterize Coleman as an overly optimistic, impractical College student. Quite the contrary Coleman is one of the most practical grounded flyers I know and he is generally very thorough in his analysis. Not perfect but much better than most hobbyists I know, let alone the average rocketry team College student that I have witnessed.

No offense to College students as I always tune-in with genuine interest when they are up at bat.
 
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MClark said:
Red propellant, why? Low ISP and hard to light.
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It's a commercial motor. Look at the difference in impulse between the M1378 and the L2050 and it's very clear why they chose that motor. The M1378 is a pretty incredible motor.
 
Maxwelljets said:
It's a commercial motor. Look at the difference in impulse between the M1378 and the L2050 and it's very clear why they chose that motor. The M1378 is a pretty incredible motor.
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Yes, it's a 54mm baby M (5%) with an Isp=210s. Not a bad choice. But, red propellant is typically more difficult to light.
 
jsdemar said:
Yes, it's a 54mm baby M (5%) with an Isp=210s. Not a bad choice. But, red propellant is typically more difficult to light.
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There are no other 54mm M motors out there that are easier to light. Their design only really works with that particular motor.
 
Kudos for trying. What people forget is this was a extremely difficult thing to do. They've tried to do something that most of us won't even think of doing.

Maybe next time....
 
I have found that the Loki red reload very hard to light. Much harder then Aerotech's redline and much harder then the other Loki reloads.
 
cbrarick said:
Kudos for trying. What people forget is this was a extremely difficult thing to do. They've tried to do something that most of us won't even think of doing.
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For a first try at a high altitude student-build rocket, it was an excellent project. The limitations of using commercial motors added some challenges. And launching this early at Spaceport America, with the high upper-level winds, made it very difficult (not worth trying, IMO).

A follow-up report would be very helpful for those planning such flights in the future. RASAero II with the wind profile and best-estimate of the rocket mass&moments would be interesting to compare with the flight data.

Also, it would be interesting to see how the onboard IMU performed and if it correctly qualified the 2nd-stage ignition.
 
From their Facebook page:

"We had a successful launch at 0939 MDT yesterday. After a successful boost phase of the first stage, the second stage igniter failed to initiate the upper stage motor. The second stage then reached about 50,000 ft.

We also apologize for the interruption in the live stream Spaceport America due to network issues.

Nevertheless, all other systems performed nominally leading to a perfect recovery of the sustainer 2 miles away. We are very happy with the vehicle’s performance: the full stack reached and survived max-Q at booster burnout, thermal protection surfaces acted as expected, and all onboard electronics performed perfectly. According to our trajectory analysis, we would have likely reached outer space if the second stage had ignited. More data and video will follow.

We look forward to making another attempt in the future, building off lessons learned in both the construction and launch phases of the project!"
 
I love student projects. No matter how bad the failure it will be spun into being successful.
Try doing that in the real world.

M
 
MClark said:
I love student projects. No matter how bad the failure it will be spun into being successful.
Try doing that in the real world.

M
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No corporate failure is too big for corporate spin. I can't see this as any different.

Edit to add, looks like Pit beat me to it.
 
mpitfield said:
That is precisely how winners do things in "the real world". They don't dwell on mistakes, they don't beat themselves up they learn from them and move forward.
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No, it is not the way it is done in the real World. A contract has specific deliverables with performance requirements. You miss those and you don't get paid. If you misrepresent your abilities or results, you may get sued.

Learning from mistakes is ok for students and corporate internal R&D. The better approach is to learn best practices, follow a good engineering process, and minimize problems.
 
I don't think all this carping about how they wrote a Facebook post reflects very well on our community. They tried and it was a credible effort IMHO. Let's wait and see what the after-action details look like.
 
MClark said:
I love student projects. No matter how bad the failure it will be spun into being successful.
Try doing that in the real world.

M
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Does shitting on other people's efforts make you feel good about yourself?
 
jsdemar said:
No, it is not the way it is done in the real World. A contract has specific deliverables with performance requirements. You miss those and you don't get paid. If you misrepresent your abilities or results, you may get sued.

Learning from mistakes is ok for students and corporate internal R&D. The better approach is to learn best practices, follow a good engineering process, and minimize problems.
Click to expand...

You're conflating the context of my response with something larger.

I was simply pointing out that there is nothing wrong with putting a positive spin on this as there were arguably many more "successful" components to their efforts vs. "failed" and that by highlighting the failings is not a good formula to move things forward. And that in the real world, or world of business if you want to draw business into the discussion, a positive attitude helps on may levels.
 
mpitfield said:
You're conflating the context of my response with something larger.

I was simply pointing out that there is nothing wrong with putting a positive spin on this as there were arguably many more "successful" components to their efforts vs. "failed" and that by highlighting the failings is not a good formula to move things forward. And that in the real world, or world of business if you want to draw business into the discussion, a positive attitude helps on may levels.
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Fair enough. But your reply was already on the context of technical success in the business World, replying to Mark's point.

"Winning" for a student project like this is to learn new skills, make a good impression on potential employers, and impress sponsors for the next group's fundraising. They seem to have succeeded.
 
MClark said:
I love student projects. No matter how bad the failure it will be spun into being successful.
Try doing that in the real world.

M
Click to expand...

Seemed less like spin and more like "this is what worked, this is what didn't"

Since they're not filling a contract, and are planning to learn from this and attempt again, in a process of learning.... Who cares that they're trying to remain upbeat in the face of failure? I'd be more disappointed if they posted the anger and defeat they're likely feeling right now, and you'd be jumping on them for an unprofessional/emotional response.

I love peoples comments on student projects. No matter what the kids do or say, you can jump all over them.
 
DavidMcCann said:
Seemed less like spin and more like "this is what worked, this is what didn't"

Since they're not filling a contract, and are planning to learn from this and attempt again, in a process of learning.... Who cares that they're trying to remain upbeat in the face of failure? I'd be more disappointed if they posted the anger and defeat they're likely feeling right now, and you'd be jumping on them for an unprofessional/emotional response.

I love peoples comments on student projects. No matter what the kids do or say, you can jump all over them.
Click to expand...

I think most of the responses here have been positive. I'd like to see it return to the technical aspects of the project to the benefit of others contemplating such things.

With that said, it's not surprising that people will be critical when a group presents themselves as already succeeding even before the test flight takes place. (See their website). There also has to be some latitude to allow people to be critical of the technical details in their design to allow improvements, before and after the flight.
 
jsdemar said:
And launching this early at Spaceport America, with the high upper-level winds, made it very difficult (not worth trying, IMO).
Click to expand...
Their FAA waiver application had a lot of detail about upper-level winds at this date. What's your specific concern? Their predict from average winds had the sustainer landing about 8 nautical miles from the launch site.
 

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