Aerotech Space Challenge

[cwbullet]

I can get to here:
https://www.rocketmotorparts.com/page/motor-assembly-drawings

But trying to get to any of the drawings still shows

Odd. It comes up for me. I wonder if it is a local or regional name server issue.

 

[SolarYellow]

It's been under discussion in the AeroTech thread for a couple days. I wish they'd get it sorted, as I would like to download several drawings.

 

[AeroTech]

It's been under discussion in the AeroTech thread for a couple days. I wish they'd get it sorted, as I would like to download several drawings.

It appears to be fixed now.

 

[SolarYellow]

It appears to be fixed now.

Working for me. Thanks!

 

[Cooperr]

@AeroTech are the space challenge rules available?

 

[VernK]

What sort of tracking data is going to be required to prove a flight has successfully crossed the 100km altitude for this prize?

 

[AeroTech]

@AeroTech are the space challenge rules available?

Not yet but soon.

 

[AeroTech]

What sort of tracking data is going to be required to prove a flight has successfully crossed the 100km altitude for this prize?

It will be something like this:

“Rockets must use two or more NAR and TRA-recognized onboard altimeters for altitude determination. The altimeters must agree to within 2% of each other and the average of them will be used to determine the final altitude. Rockets reporting only one altitude will be disqualified.“

 

[rcktnut]

View attachment 626880

Just came across this....interesting, but I'm not sure if it can be done with only 40,960 N-s

 

[Neutronium95]

It will be something like this:

“Rockets must use two or more NAR and TRA-recognized onboard altimeters for altitude determination. The altimeters must agree to within 2% of each other and the average of them will be used to determine the final altitude. Rockets reporting only one altitude will be disqualified.“

That's not going to work. Barometric altimeters aren't going to give accurate data above 100k feet. Tripoli requires GPS verification for records above 30k MSL, and the only GPS unit that works at 100km is the Multitronix Kate. And while Kate is massively capable, it's so large and so expensive that requiring two would make the challenge significantly harder and more expensive.

It should be possible to derive a relatively accurate apogee with a GPS unit that's limited to 80km, since there's almost no drag, so it's a pretty simple mechanics calculation.

 

[Reinhard]

It should be possible to derive a relatively accurate apogee with a GPS unit that's limited to 80km, since there's almost no drag, so it's a pretty simple mechanics calculation.

A rocket that reaches 100km+ will be passing the 80km mark at 626m/s+. That's above the current limits for export controlled GNSS receivers of 600m/s (see the USML: 22 CFR part 121, Category XII (d)(2)(iv), which I guess is the US implementation of MTCR Annex 11.A.3.b.1.). Most GNSS receivers will observe even stricter standards like the historic CoCom limit of 1000knots (515 m/s). The last time I looked, u-blox observed a 500m/s limit.

In other words, with a 80km limited receiver, there will be no data from the micro-gravity portion of the flight that can be extrapolated for a reasonably accurate apogee determination.

Reinhard

 

[Zertyme]

A rocket that reaches 100km+ will be passing the 80km mark at 626m/s+. That's above the current limits for export controlled GNSS receivers of 600m/s (see the USML: 22 CFR part 121, Category XII (d)(2)(iv), which I guess is the US implementation of MTCR Annex 11.A.3.b.1.). Most GNSS receivers will observe even stricter standards like the historic CoCom limit of 1000knots (515 m/s). The last time I looked, u-blox observed a 500m/s limit.

In other words, with a 80km limited receiver, there will be no data from the micro-gravity portion of the flight that can be extrapolated for a reasonably accurate apogee determination.

Reinhard

I have found a few, easily available modules that have a maximum altitude above 100km (but still a velocity limit of around 500-600m/s).
Those should allow for GNSS altitude verification above 100km. A friend of mine is planning on doing GNSS testing using a GNSS simulator to verify those dynamic constraints. I'll also do a few launch tests to verify the modules' performances in real flights. I'll share the results once everything is tested.

 

[VernK]

I have found a few, easily available modules that have a maximum altitude above 100km (but still a velocity limit of around 500-600m/s).

Some of those GPS units may require to be reset once the speed drops below 500m/s. In order words, a cold start is needed and the GPS will have to reacquire and relock onto the satellites as it is coasting up toward apogee. To know when to reset it, the velocity derived from an accelerometer could be used. It then becomes a race to see if the GPS will relock in time to capture apogee. Good luck. The Kate GPS does not require this reset procedure. It will automatically resume reporting valid GPS data the instant the velocity drops below 500m/s.

 

[VernK]

It will be something like this: “Rockets must use two or more NAR and TRA-recognized onboard altimeters for altitude determination. ..."

Aerotech can certainly do whatever they want since this is their contest. However, I suggest they consider adopting the same rules as are used for TRA altitude records. Those rules require GPS be used for altitudes above 30K feet MSL. Those rules also allow a single GPS system to be used for the flight. Obviously, that is why I like this idea. It would allow a flyer to use a single Kate system for this contest. In my opinion, requiring a second altimeter with an additional GPS unit is really over constraining the flyer. Makes it even more difficult to reach 100 km given the motors required for this flight. GPS accuracy is plenty good enough even coming from a single unit.

 

[RocketMan3D]

I really, REALLY wish I was
1 18+
2 had a L3
3 had money
So I could compete ahhh well

Ps does anyone that is competing need a side kick?

Me too.

 

[NTP2]

Me too.

We can form team “we should not be competing but we are stubborn”